Network Working Group                                      S. Nandakumar
Internet-Draft                                               C. Jennings
Intended status: Informational                                     Cisco
Expires: February 13, 2015                               August 12, 2014


                           SDP for the WebRTC
                     draft-nandakumar-rtcweb-sdp-05

Abstract

   The Web Real-Time Communication [WebRTC] working group is charged to
   provide protocol support for direct interactive rich communication
   using audio, video and data between two peers' web browsers.  With in
   the WebRTC framework, Session Description protocol (SDP) [RFC4566] is
   used for negotiating session capabilities between the peers.  Such a
   negotiation happens based on the SDP Offer/Answer exchange mechanism
   described in the RFC 3264 [RFC3264].

   This document provides an informational reference in describing the
   role of SDP and the Offer/Answer exchange mechanism for the most
   common WebRTC use-cases.

   This SDP examples provided in this document is still a work in
   progress, but it aims to align closest to the evolving standards
   work.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 13, 2015.








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Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  SDP and the WebRTC  . . . . . . . . . . . . . . . . . . . . .   3
   4.  Offer/Answer and the WebRTC . . . . . . . . . . . . . . . . .   4
   5.  WebRTC Session Description Examples . . . . . . . . . . . . .   5
     5.1.  Some Conventions  . . . . . . . . . . . . . . . . . . . .   5
     5.2.  Basic Examples  . . . . . . . . . . . . . . . . . . . . .   7
       5.2.1.  Two-Way Audio Only Session  . . . . . . . . . . . . .   7
       5.2.2.  Two-Way Audio/Video Session . . . . . . . . . . . . .  10
       5.2.3.  Two-Way Data Only Session . . . . . . . . . . . . . .  15
       5.2.4.  Audio Call On Hold  . . . . . . . . . . . . . . . . .  17
       5.2.5.  Audio with DTMF Session . . . . . . . . . . . . . . .  20
       5.2.6.  One Way Audio/Video Session - Document Camera . . . .  25
       5.2.7.  Audio, Video Session with BUNDLE Support Unknown  . .  29
       5.2.8.  Audio, Video and Data Session . . . . . . . . . . . .  36
       5.2.9.  Two-Way Audio,Video w/BUNDLE Unsupported  . . . . . .  41
       5.2.10. Audio, Video BUNDLED but Data Not BUNDLED . . . . . .  46
       5.2.11. Audio Only then Add Video and BUNDLE  . . . . . . . .  50
     5.3.  MultiResolution, RTX, FEC Examples  . . . . . . . . . . .  57
       5.3.1.  Sendonly Simulcast w/2 cameras and 2 encodings per
               camera  . . . . . . . . . . . . . . . . . . . . . . .  57
       5.3.2.  Successful SVC Video Stream . . . . . . . . . . . . .  64
       5.3.3.  Successful Simulcast Video Streams with Retransmisson  68
       5.3.4.  Successful 1-way Simulcast with 2 resolutions and RTX
               - One resolution rejected . . . . . . . . . . . . . .  73
       5.3.5.  Simulcast Video Stream with Forward Error Correction   78
     5.4.  Others  . . . . . . . . . . . . . . . . . . . . . . . . .  83
       5.4.1.  Audio Session - Voice Activity Detection  . . . . . .  83
       5.4.2.  Audio Conference - Voice Activity Detection . . . . .  86
       5.4.3.  Successful legacy Interop Fallaback with bundle-only   89
       5.4.4.  Legacy Interop with RTP/AVP profile . . . . . . . . .  94



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   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  99
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  99
   8.  Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .  99
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . . 100
     9.1.  Normative References  . . . . . . . . . . . . . . . . . . 100
     9.2.  Informative References  . . . . . . . . . . . . . . . . . 100
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 104

1.  Introduction

   Javascript Session Exchange Protocol(JSEP) [JSEP] specifies a generic
   protocol needed to generate [RFC3264] Offers and Answers negotiated
   between the WebRTC peers for setting up, updating and tearing down a
   WebRTC session.  For this purpose, SDP is used to construct [RFC3264]
   Offers/Answers for describing (media and non-media) streams as
   appropriate for the recipients of the session description to
   participate in the session.

   The remainder of this document is organized as follows: Section 3 and
   4 provides an overview of SDP and the Offer/Answer exchange
   mechanism.  Section 5 provides sample SDP generated for the most
   common WebRTC use-cases.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
   "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be
   interpreted as described in [RFC2119].

3.  SDP and the WebRTC

   The purpose of this section is to provide a general overview of SDP
   and its components.  For a more in-depth understanding, the readers
   are advised to refer to [RFC4566].

   The Session Description Protocol (SDP) [RFC4566] describes multimedia
   sessions, which can contain audio, video, whiteboard, fax, modem, and
   other streams.  SDP provides a general purpose, standard
   representation to describe various aspects of multimedia session such
   as media capabilities, transport addresses and related metadata in a
   transport agnostic manner, for the purposes of session announcement,
   session invitation and parameter negotiation.

   As of today SDP is widely used in the context of Session Initiation
   Protocol [RFC3261], Real-time Transport Protocol [RFC3550] and Real-
   time Streaming Protocol applications [RFC2326].





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   Below figure introduces high-level breakup of SDP into components
   that semantically describe a multimedia session, in our case, a
   WebRTC session [WebRTC].  It by no means captures everything about
   SDP and hence, should be used for informational purposes only.

   [WebRTC] proposes JavaScript application to fully specify and control
   the signaling plane of a multimedia session as described in the JSEP
   specification [JSEP].  JSEP provides mechanisms to create session
   characterization and media definition information to conduct the
   session based on SDP exchanges.

   In this context, SDP serves two purposes:

   1.  Provide grammatical structure syntactically.

   2.  Semantically convey partipant's intention and capabilities
       required to successfully negotiate a session.

4.  Offer/Answer and the WebRTC

   This section introduces SDP Offer/Answer Exchange mechanism mandated
   by WebRTC for negotiating session capabilities while setting up,
   updating and tearing down a WebRTC session.  This section is
   intentionally brief in nature and interested readers are recommended
   to refer [RFC3264] for specific details on the protocol operation.

   The Offer/Answer [RFC3264] model specifies rule for the bilateral
   exchange of Session Description Protocol (SDP) messages for creation
   of multimedia streams.  It defines protocol with involved
   participants exchanging desired session characteristics from each
   others perspective constructed as SDP to negotiate the session
   between them.

   In the most basic form,the protocol operation begins by one of the
   participants sending an initial SDP Offer describing its intent to
   start a multimedia communication session.  The participant receiving
   the offer MAY generate an SDP Answer accepting the offer or it MAY
   reject the offer.  If the session is accepted the Offer/Answer model
   guarantees a common view of the multimedia session between the
   participants.

   At any time, either participant MAY generate a new SDP offer that
   updates the session in progress.

   With in the context of WebRTC, the Offer/Answer model defines the
   state-machinery for WebRTC peers to negotiate session descriptions
   between them during the initial setup stages as well as for eventual
   session updates.  Javascript Session Establishment Protocol



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   specification [JSEP] for WebRTC provides the mechanism for generating
   [RFC3264] SDP Offers and Answers in order for both sides of the
   session to agree upon details such as list of media formats to be
   sent/received, bandwidth information, crypto parameters, transport
   parameters, for example.

5.  WebRTC Session Description Examples

   A typical web based real-time multimedia communication session can be
   characterized as below:

   o  It has zero or more Audio only, Video only or Audio/Video RTP
      Sessions,

   o  MAY contain zero or more non-media data sessions,

   o  All the sessions are secured with DTLS-SRTP,

   o  Supports NAT traversal using ICE mechanism,

   o  Provides RTCP based feedback mechanisms,

   o  Sessions can be over IPv4-only, IPv6-only, dual-stack based
      clients.

5.1.  Some Conventions

   The examples given in this document follow the conventions listed
   below:

   o  In all the examples, Alice and Bob are assumed to be the WebRTC
      peers.

   o  [draft-ietf-mmusic-sdp-bundle-negotiation] support for
      multiplexing several media streams on a single underlying
      transport is enabled by default unless explicitly specified
      otherwise.

   o  Call flow diagrams that accompany the use-cases capture only the
      prominent aspects of the system behavior and intentionally is not
      detailed to improve readability.

   o  The SDP examples deviate from actual on-the-wire SDP notation in
      several ways.  This is done to facilitate readability and to
      conform to the restrictions imposed by the RFC formatting rules.

      *  Any SDP line that is indented (compared to the initial line in
         the SDP block) is a continuation of the preceding line.  The



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         line break and indent are to be interpreted as a single space
         character.

      *  Empty lines in any SDP example are inserted to make functional
         divisions in the SDP clearer, and are not actually part of the
         SDP syntax.

      *  Excepting the above two conventions, line endings are to be
         interpreted as <CR><LF> pairs (that is, an ASCII 13 followed by
         an ASCII 10).

   o  Against each SDP line, pointers to the appropriate RFCs are
      provide for further information reference.  Also an attempt has
      been made to provide explanatory notes to enable better
      understanding of the SDP usage, wherever appropriate.

   o  Following SDP details are common across all the use-cases defined
      in this document unless mentioned otherwise.

      *  DTLS fingerprint for SRTP (a=fingerprint)

      *  RTP/RTCP Multiplexing (a=rtcp-mux)

      *  RTCP Feedback support (a=rtcp-fb)

      *  Host and server-reflexive candidate lines (a=candidate)

      *  SRTP Setup framework parameters (a=setup)

      *  RTCP attribute (a=rtcp)

      *  RTP header extension indicating audio-levels from client to the
         mixer

      For more details, readers are recommended to refer to the
      Javascript Session Exchange Protocol(JSEP) [JSEP] specification.

   o  The term "Session" is used rather loosely in this document to
      refer to either a "Communication Session" or a "RTP Session" or a
      "RTP Stream" depending on the context.

   o  Payload type 109 is usually used for OPUS, 99 for H.264 and 120
      for VP8 in most of the examples to maintain uniformity.

   o  In the actual use that values that represent SSRCs, ICE candidate
      foundations, WebRTC Mediastream and MediaStreamTrack Ids can be
      much larger and random than the ones shown in the examples.




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      [OPEN ISSUE-1]: SDP Examples for Data Channel, Simulcast, SVC are
      still being discussed and doesn't represent the final solution.

      [OPEN ISSUE-2]: API surface for controlling BUNDLE, TRICKLE-ICE
      are ignored for the time being.

5.2.  Basic Examples

5.2.1.  Two-Way Audio Only Session

   This common scenario shows SDP for secure Two-way audio session with
   Alice offering Opus, PCMU, PCMA and Bob accepting all the audio
   codecs offered.

   title 2-Way Audio Only Session

   participant Alice as Alice
   participant Bob as Bob

   Alice->Bob: Offer(Audio:Opus,PCMU,PCMA)
   Bob->Alice: Answer(Audio:Opus,PCMU,PCMA)
   Alice<->Bob: Two-way Opus Audio (preferred codec)

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | 0 8                                  |                            |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus Codec 48khz, 2  |
   |                                      | channels                   |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |



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   |                                      | us] - Opus packetization   |
   |                                      | of 20ms                    |
   | a=rtpmap:0 PCMU/8000                 | [RFC3551] PCMU Audio Codec |
   | a=rtpmap:8 PCMA/8000                 | [RFC3551] PCMA Audio Codec |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464] Alice supports   |
   | hdrext:ssrc-audio-level              | RTP header extension to    |
   |                                      | indicate audio levels      |
   | a=sendrecv                           | [RFC3264] - Alice can send |
   |                                      | and recv audio             |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761] - Alice can      |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 54609                 |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=ice-ufrag:074c6550                 | [RFC5245] - ICE user       |
   |                                      | fragment                   |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245] - ICE password   |
   | f08a068                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245] - RTP Host       |
   | 192.168.1.4 54609 typ host           | Candidate                  |
   | a=candidate:1 1 UDP  694302207       | [RFC5245] - RTP Server     |
   | 24.23.204.141 54609 typ srflx raddr  | Reflexive ICE Candidate    |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245] - RTCP Host      |
   | 192.168.1.4 64678 typ host           | Candidate                  |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245] - RTCP Server    |
   | 24.23.204.141 64678 typ srflx raddr  | Reflexive Candidate        |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104] - Indicates NACK |
   |                                      | RTCP feedback support      |
   | a=ssrc:12345 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506] - Alice intends  |
   |                                      | to use reduced size RTCP   |
   |                                      | for this session           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 1: 5.2.1 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |



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   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | 0 8                                  |                            |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] Opus Codec             |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us] Packetization of 20ms  |
   | a=rtpmap:0 PCMU/8000                 | [RFC3551] PCMU Audio Codec |
   | a=rtpmap:8 PCMA/8000                 | [RFC3551] PCMA Audio Codec |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464] Bob supports     |
   | hdrext:ssrc-audio-level              | audio level RTP header     |
   |                                      | extension as well          |
   | a=sendrecv                           | [RFC3264] - Bob can send   |
   |                                      | and recv audio             |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761] - Bob can        |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 49203                 |
   | a=fingerprint:sha-1 c9:c7:70:9d:1f:6 | [RFC5245] - DTLS           |
   | 6:79:a8:07:99:41:49:83:4a:97:0e:1f:e | Fingerprint for SRTP       |
   | f:6d:f7                              |                            |
   | a=ice-ufrag:05067423                 | [RFC5245] - ICE user       |
   |                                      | fragment                   |
   | a=ice-pwd:1747d1ee3474a28a397a4c3f3a | [RFC5245] - ICE password   |
   | f08a068                              | parameter                  |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245] - RTP Host ICE   |
   | 192.168.1.7 49203 typ host           | Candidate for Opus Stream  |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245] - RTP Server     |
   | 98.248.92.77 49203 typ srflx raddr   | Reflexive ICE Candidate    |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245] - RTCP Host      |
   | 192.168.1.7 60065 typ host           | Candidate                  |



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   | a=candidate:1 2 UDP 1694302206       | [RFC5245] - RTCP Server    |
   | 98.248.92.77 60065 typ srflx raddr   | Reflexive Candidate        |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104] - Indicates NACK |
   |                                      | RTCP feedback support      |
   | a=ssrc:54321                         | [RFC5576]                  |
   | cname:NWs1ao1HmN4Xa5/yvY7            |                            |
   | a=rtcp-rsize                         | [RFC5506] - Bob intends to |
   |                                      | use reduced size RTCP for  |
   |                                      | this session               |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 2: 5.2.1 SDP Answer

5.2.2.  Two-Way Audio/Video Session

   Alice and Bob establish an audio and video session with Opus as the
   audio codec and H.264 as the video codec.  This example also
   illustrates the negotiation of NACK based RTCP feedback mechanisms -
   PLI and FIR for the video session [RFC5104].

   title 2-Way Audio,Video Session

   Alice->Bob: Offer(Audio:Opus,PCMU,PCMA Video:H.264,VP8)
   Bob->Alice: Answer(Audio:Opus, Video:H.264)
   Alice->Bob: Two-way Opus Audio, H.264 Video

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | 0 8                                  |                            |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |



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   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus Codec 48khz, 2  |
   |                                      | channels                   |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus packetization   |
   |                                      | of 20ms                    |
   | a=rtpmap:0 PCMU/8000                 | [RFC3551] PCMU Audio Codec |
   | a=rtpmap:8 PCMA/8000                 | [RFC3551] PCMA Audio Codec |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=sendrecv                           | [RFC3264] - Alice can send |
   |                                      | and recv audio             |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761] - Alice can      |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 54609                 |
   | a=ice-ufrag:074c6550                 | [RFC5245] - ICE user       |
   |                                      | fragment                   |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245] - ICE password   |
   | f08a068                              | parameter                  |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245] - RTP ICE        |
   | 192.168.1.4 54609 typ host           | Candidate                  |
   | a=candidate:1 1 UDP  694302207       | [RFC5245] - RTP Server     |
   | 24.23.204.141 54609 typ srflx raddr  | Reflexive ICE Candidate    |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245] - RTCP Host      |
   | 192.168.1.4 64678 typ host           | Candidate                  |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245] - RTCP Server    |
   | 24.23.204.141 64678 typ srflx raddr  | Reflexive Candidate.       |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104] - Indicates NACK |
   |                                      | RTCP feedback support      |
   | a=ssrc:12345 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506] - Alice intends  |
   |                                      | to use reduced size RTCP   |
   |                                      | for this session           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=video 54609 UDP/TLS/RTP/SAVPF 99   | [RFC4566]                  |
   | 120                                  |                            |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |



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   | a=mid:video                          | [RFC5888]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:99 H264/90000               | [RFC3984] - H.264 Video    |
   |                                      | Codec                      |
   | a=fmtp:99 profile-level-id=4d0028    | [RFC3984]                  |
   | ;packetization-mode=1                |                            |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8] - |
   |                                      | VP8 video codec            |
   | a=sendrecv                           | [RFC3264] - Alice can send |
   |                                      | and recv video             |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761] - Alice can      |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 62537                 |
   | a=ice-ufrag:074c6550                 | [RFC5245] - ICE user       |
   |                                      | fragment                   |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245] - ICE password   |
   | f08a068                              | parameter                  |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245] - RTP Host ICE   |
   | 192.168.1.4 54609 typ host           | Candidate                  |
   | a=candidate:1 1 UDP  694302207       | [RFC5245] - RTP Server     |
   | 24.23.204.141 54609 typ srflx raddr  | Reflexive ICE Candidate    |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245] - RTCP Host      |
   | 192.168.1.4 64678 typ host           | Candidate                  |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245] - RTCP Server    |
   | 24.23.204.141 64678 typ srflx raddr  | Reflexive Candidate        |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:99 nack                    | [RFC5104] - Indicates NACK |
   |                                      | RTCP feedback support      |
   | a=rtcp-fb:99 nack pli                | [RFC5104] - Indicates      |
   |                                      | support for Picture loss   |
   |                                      | Indication and NACK        |
   | a=rtcp-fb:99 ccm fir                 | [RFC5104] - Full Intra     |
   |                                      | Frame Request-Codec        |
   |                                      | Control Message support    |
   | a=rtcp-fb:120 nack                   | [RFC5104] - Indicates NACK |
   |                                      | RTCP feedback support      |



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   | a=rtcp-fb:120 nack pli               | [RFC5104] - Indicates      |
   |                                      | support for Picture loss   |
   |                                      | Indication and NACK        |
   | a=rtcp-fb:120 ccm fir                | [RFC5104] - Full Intra     |
   |                                      | Frame Request-Codec        |
   |                                      | Control Message support    |
   | a=ssrc:1366781083                    | [RFC5576]                  |
   | cname:EocUG1f0fcg/yvY7               |                            |
   | a=rtcp-rsize                         | [RFC5506] - Alice intends  |
   |                                      | to use reduced size RTCP   |
   |                                      | for this session           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 3: 5.2.2 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Bob accepts only     |
   |                                      | Opus Codec                 |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264] - Bob can send   |
   |                                      | and recv audio             |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |



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   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761] - Bob can        |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 49203                 |
   | a=ice-ufrag:c300d85b                 | [RFC5245] -  ICE username  |
   |                                      | frag                       |
   | a=ice-                               | [RFC5245] - ICE password   |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245] - RTP Host ICE   |
   | 192.168.1.7 49203 typ host           | Candidate for Opus Stream  |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245] - RTP Server     |
   | 98.248.92.77 49203 typ srflx raddr   | Reflexive ICE Candidate    |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245] - RTPC Host      |
   | 192.168.1.7 60065 typ host           | Candidate                  |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245] - RTCP Server    |
   | 98.248.92.77 60065 typ srflx raddr   | Reflexive Candidate.       |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:1366788312                    | [RFC5576]                  |
   | cname:1f0fcgEocUG/yvY7               |                            |
   | a=rtcp-rsize                         | [RFC5506] - Bob intends to |
   |                                      | use reduced size RTCP for  |
   |                                      | this session               |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=video 49203 UDP/TLS/RTP/SAVPF 99   | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:99 H264/90000               | [RFC3984] - Bob accepts    |
   |                                      | H.264 Video Codec.         |
   | a=fmtp:99 profile-level-id=4d0028    | [RFC3984]                  |
   | ;packetization-mode=1                |                            |
   | a=sendrecv                           | [RFC3264] - Bob can send   |
   |                                      | and recv video             |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761] - Bob can        |
   |                                      | perform RTP/RTCP Muxing on |



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   |                                      | port 63130                 |
   | a=ice-ufrag:c300d85b                 | [RFC5245] -  ICE username  |
   |                                      | frag                       |
   | a=ice-                               | [RFC5245] - ICE password   |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245] - Host ICE       |
   | 192.168.1.7 49203 typ host           | Candidate for Opus Stream  |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245] - Server         |
   | 98.248.92.77 49203 typ srflx raddr   | Reflexive ICE Candidate    |
   | 192.168.1.7 rport 49203              | for the above host         |
   |                                      | candidate                  |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245] - Second Host    |
   | 192.168.1.7 60065 typ host           | Candidate                  |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245] - Server         |
   | 98.248.92.77 60065 typ srflx raddr   | Reflexive Candidate for    |
   | 192.168.1.7 rport 60065              | the Second Host Candidate  |
   | a=rtcp-fb:99 nack                    | [RFC5104] - Indicates      |
   |                                      | support for NACK based     |
   |                                      | RTCP feedback              |
   | a=rtcp-fb:99 nack pli                | [RFC5104] - Indicates      |
   |                                      | support for Picture loss   |
   |                                      | Indication and NACK        |
   | a=rtcp-fb:99 ccm fir                 | [RFC5104] - Full Intra     |
   |                                      | Frame Request-Codec        |
   |                                      | Control Message support    |
   | a=ssrc:3229706345                    | [RFC5576]                  |
   | cname:Q/NWs1ao1HmN4Xa5               |                            |
   | a=rtcp-rsize                         | [RFC5506] - Bob intends to |
   |                                      | use reduced size RTCP for  |
   |                                      | this session               |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 4: 5.2.2 SDP Answer

5.2.3.  Two-Way Data Only Session

   This scenario illustrates SDP negotiated to setup a data-only session
   based on SCTP Data Channel, thus enabling use-cases such as file-
   transfer for example.







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   title WebRTC Session - 2-Way Secure Audio,Video with RTCP Feedback
   Alice->Bob: Offer(DataChannel)
   Bob->Alice: Answer(Data-Channel)
   Alice->Bob: Two-way SCTP based Data-Channel

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE data                  | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-ufrag:074c6550                 | [RFC5245] - Session Level  |
   |                                      | ICE parameter              |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245] - Session Level  |
   | f08a068                              | ICE parameter              |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - Session DTLS   |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | m=application 56966 DTLS/SCTP 5000   | [draft-ietf-rtcweb-data-ch |
   |                                      | annel]                     |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:data                           | [RFC5888]                  |
   | a=sctpmap:5000 webrtc-DataChannel    | [draft-ietf-mmusic-sctp-sd |
   | streams=16;label="channel            | p]                         |
   | 1";subprotocol="chat";               |                            |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=sendrecv                           | [RFC3264] - Alice can send |
   |                                      | and recv non-media data    |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 56966 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 24.23.204.141 56966 typ srflx raddr  |                            |
   | 192.168.1.7 rport 56966              |                            |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 5: 5.2.3 SDP Offer






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   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE data                  | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=application 55700 DTLS/SCTP 5000   | [draft-ietf-mmusic-sctp-sd |
   |                                      | p]                         |
   | c=IN IP4 98.248.92.771               | [RFC4566]                  |
   | a=mid:data                           | [RFC5888]                  |
   | a=sctpmap:5000 webrtc-               | [draft-ietf-mmusic-sctp-sd |
   | DataChannel:5000                     | p]                         |
   | streams=1;label="channel             |                            |
   | 1";subprotocol="chat";               |                            |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=sendrecv                           | [RFC3264] - Bob can send   |
   |                                      | and recv non-media data    |
   | a=ice-ufrag:c300d85b                 | [RFC5245] - Session Level  |
   |                                      | ICE username frag          |
   | a=ice-                               | [RFC5245] - Session Level  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 | ICE password               |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - Session DTLS   |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245] - Refer 4.1 SDP  |
   | 192.168.1.7 55700 typ host           | Offer                      |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245] Refer 4.1 SDP    |
   | 98.248.92.77 55700 typ srflx raddr   | Offer                      |
   | 192.168.1.7 rport 55700              |                            |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 6: 5.2.3 SDP Answer

5.2.4.  Audio Call On Hold

   Alice calls Bob, but when Bob answers he places Alice on hold by
   setting the SDP direction attribute to a=sendonly in the Answer.





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   title Secure 2-Way Audio Only Session
   participant Alice as Alice
   participant Bob as Bob
   Alice->Bob: Offer(Audio:Opus)
   Bob->Alice: Answer(Audio:Opus,a=sendonly)
   Alice->Bob: One-way Opus Audio (preferred codec)

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus Codec 48khz, 2  |
   |                                      | channels                   |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus packetization   |
   |                                      | of 20ms                    |
   | a=sendrecv                           | [RFC3264] - Alice can send |
   |                                      | and recv audio             |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761] - Alice can      |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 54609                 |
   | a=ice-ufrag:074c6550                 | [RFC5245] -  ICE user      |
   |                                      | fragment                   |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245] -  ICE password  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |



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   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104] - Indicates NACK |
   |                                      | RTCP feedback support      |
   | a=ssrc:3229706345                    | [RFC5576]                  |
   | cname:Q/NWs1ao1HmN4Xa5               |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 7: 5.2.4 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Bob accepts only     |
   |                                      | Opus Codec                 |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |



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   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendonly                           | [RFC3264] - Bob puts call  |
   |                                      | On Hold                    |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761] - Bob can        |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 49203                 |
   | a=ice-ufrag:c300d85b                 | [RFC5245] - ICE username   |
   |                                      | frag                       |
   | a=ice-                               | [RFC5245] - ICE password   |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:1366781083                    | [RFC5576]                  |
   | cname:EocUG1f0fcg/yvY7               |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 8: 5.2.4 SDP Answer

5.2.5.  Audio with DTMF Session

   In this example, Alice wishes to establish two separate audio
   streams, one for normal audio and the other for telephone-events.
   Alice offers first audio stream with three codecs and the other with
   [RFC2833] tones (for DTMF).  Bob accepts both the audio streams by
   choosing Opus as the audio codec and the telephone-event for the
   other stream.







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   title Audio Session with DTMF
   participant Alice as Alice
   participant Bob as Bob
   Alice->Bob: Offer(Audio:Opus,PCMU,PCMA Audio:telephone-event)
   Bob->Alice: Answer(Audio:Opus, Audio:telephone-event)
   Alice->Bob: Opus audio stream and telephone-event stream

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio dtmf            | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | 0 8                                  |                            |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus Codec 48khz, 2  |
   |                                      | channels                   |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus packetization   |
   |                                      | of 20ms                    |
   | a=rtpmap:0 PCMU/8000                 | [RFC3551] PCMU Audio Codec |
   | a=rtpmap:8 PCMA/8000                 | [RFC3551] PCMA Audio Codec |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=sendrecv                           | [RFC3264] - Alice can send |
   |                                      | and recv audio             |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761] - Alice can      |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 54609                 |
   | a=ice-ufrag:074c6550                 | [RFC5245] -  ICE user      |
   |                                      | fragment                   |



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   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245] - ICE password   |
   | f08a068                              | parameter                  |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104] - Indicates NACK |
   |                                      | RTCP feedback support      |
   | a=ssrc:3229706345                    | [RFC5576]                  |
   | cname:Q/NWs1ao1HmN4Xa5               |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 126  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:dtmf                           | [RFC5888]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:126 telephone-event/8000    | [RFC2833]                  |
   | a=sendonly                           | [RFC3264] - Alice can send |
   |                                      | DTMF Events                |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245] -  ICE user      |
   |                                      | fragment                   |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245] - ICE password   |
   | f08a068                              | parameter                  |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] - DTLS           |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | Fingerprint for SRTP       |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |



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   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104] - Indicates NACK |
   |                                      | RTCP feedback support      |
   | a=ssrc:9032206345                    | [RFC5576]                  |
   | cname:L/N9lk1ao1HmN4Xa5              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 9: 5.2.5 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio dtmf            | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Bob accepts Opus     |
   |                                      | Codec                      |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264] - Bob can send   |
   |                                      | and receive Opus audio     |
   | a=setup:active                       | [RFC4145] - Bob carries    |



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   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761] - Bob can        |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 49203                 |
   | a=ice-ufrag:c300d85b                 | [RFC5245] -  ICE username  |
   |                                      | frag                       |
   | a=ice-                               | [RFC5245] -  ICE password  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] -  Fingerprint   |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | for SRTP                   |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:0634322975                    | [RFC5576]                  |
   | cname:Q/o1HmN4XNWs1aa5               |                            |
   | a=rtcp-rsize                         | [RFC5506] - Alice intends  |
   |                                      | to use reduced size RTCP   |
   |                                      | for this session           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 126  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:dtmf                           | [RFC5888]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:126 telephone-event/8000    | [RFC2833]                  |
   | a=recvonly                           | [RFC3264] - Alice can      |
   |                                      | receive DTMF events        |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761] - Alice can      |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 54690                 |
   | a=ice-ufrag:c300d85b                 | [RFC5245] -  ICE username  |



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   |                                      | frag                       |
   | a=ice-                               | [RFC5245] -  ICE password  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245] -  Fingerprint   |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 | for SRTP                   |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:6345903220                    | [RFC5576]                  |
   | cname:L/k1aN9lo1HmN4Xa5              |                            |
   | a=rtcp-rsize                         | [RFC5506] - Alice intends  |
   |                                      | to use reduced size RTCP   |
   |                                      | for this session           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                        Table 10: 5.2.5 SDP Answer

5.2.6.  One Way Audio/Video Session - Document Camera

   In this scenario Alice and Bob engage in 1 way audio and video
   session with Bob receiving Alice's audio and her presentation slides
   as video stream.



















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   title 1 Way Audio & Video Session - Document Camera

   note right of Alice
   Alice Offers sendonly audio and video streams.
   The video stream corresponds to her presentation
   slides via a=content SDP attribute)
   end note
   Alice->Bob: Offer(Audio:Opus, Video: VP8)
   note left of Bob
   Bob accepts Alice's offer
   end note
   Bob->Alice: Answer(Audio:Opus, Video: VP8)
   Alice->Bob: One-way Opus Audio, VP8 Video
   note right of Alice
   Bob can hear Alice and see her presentation slides.
   end note

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendonly                           | [RFC3264] - Send only      |
   |                                      | audio stream               |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |



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   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 24.23.204.141 54609 typ host         |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5104]                  |
   | 24.23.204.141 64678 typ host         |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ssrc:6345903220                    | [RFC5576]                  |
   | cname:L/k1aN9lo1HmN4Xa5              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=video 54609 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=content:slides                     | [RFC4796] -Alice's         |
   |                                      | presentation video stream  |
   | a=sendonly                           | [RFC3264] - Send only      |
   |                                      | video stream               |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 24.23.204.141 54609 typ host         |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5104]                  |
   | 24.23.204.141 64678 typ host         |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=ssrc:3429951804                    | [RFC5576]                  |



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   | cname:Q/NWs1ao1HmN4Xa5               |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 11: 5.2.6 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 16833 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=recvonly                           | [RFC3264] - Receive only   |
   |                                      | audio stream               |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 98.248.92.77 49203 typ host          |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |



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   | 98.248.92.77 60065 typ host          |                            |
   | a=ssrc:9513429804                    | [RFC5576]                  |
   | cname:Q/o1HmNWs1aN4Xa5               |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=video 49203 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=content:slides                     | [RFC4796]                  |
   | a=recvonly                           | [RFC3264] - Receive Only   |
   |                                      | Alice's presentation       |
   |                                      | stream                     |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 98.248.92.77 49203 typ host          |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 98.248.92.77 60065 typ host          |                            |
   | a=ssrc:1366781083                    | [RFC5576]                  |
   | cname:EocUG1f0fcg/yvY7               |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                        Table 12: 5.2.6 SDP Answer

5.2.7.  Audio, Video Session with BUNDLE Support Unknown

   In this example, since Alice is unsure of the Bob's support of the
   BUNDLE framework, following 3 step procedures are performed in order
   to negotiate and setup a unique BUNDLE Address for the session



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   o  An SDP Offer, in which the Alice assigns unique addresses to each
      "m=" line in the BUNDLE group, and requests the Answerer to select
      the Offerer's BUNDLE address.

   o  An SDP Answer, in which the Bob indicates its support for BUNDLE,
      and assigns its own BUNDLE address for the BUNDLED m= lines.

   o  A subsequent SDP Offer from Alice, which is used to perform a
      BUNDLE Address Synchronization (BAS).

   Once the Offer/Answer exchange completes, both Alice and Bob each end
   up using single RTP Session for both the Media Streams.

title 2-Way Secure Audio,Video with BUNDLE support unknown

Alice->Bob: Offer(Audio:Opus Video:VP8)
note right of Alice
Alice offers BUNDLE support with unique address for the audio and video m-line
end note

Bob->Alice: Answer(Audio:Opus Video:VP8) indicating its support for BUNDLE
note left of Bob
Bob uses identical addresses across the m=lines
end note

Alice->Bob: Updated Offer(Audio:Opus Video:VP8) for Bundle Address Synchronzation.

Alice <-> Bob: 2Way Call with Audio and Video Multiplexed

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |



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   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:11111 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=video 62537 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:video                          | [RFC5888] Video m=line     |
   |                                      | part of the Bundle group   |
   |                                      | with a unique port number  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:54721 IN IP4 24.23.204.141    | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |



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   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:22222 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ice-ufrag:6550074c                 | [RFC5245]                  |
   | a=ice-pwd:74af08a068a28a397a4c3f3174 | [RFC5245]                  |
   | 7d1ee34                              |                            |
   | a=fingerprint:sha-1 1f:ef:6d:f7:c9:c | [RFC5245]                  |
   | 7:70:9d:1f:66:99:41:49:83:4a:97:0e79 |                            |
   | :a8:07                               |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 62537 typ host           |                            |
   | a=candidate:1 1 UDP  1694302207      | [RFC5245]                  |
   | 24.23.204.141 62537 typ srflx raddr  |                            |
   | 192.168.1.4 rport 62537              |                            |
   | a=candidate:0 2 2113667326           | [RFC5245]                  |
   | 192.168.1.4 54721 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 24.23.204.141 54721 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54721              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                    Table 13: 5.2.7 SDP Offer w/BUNDLE

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Bob       |
   |                                      | supports BUNDLE semantics. |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |



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   |                                      | (ta)                       |
   | a=mid:audio                          | [RFC5888] Audio m=line     |
   |                                      | part of the BUNDLE group   |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |
   |                                      | data                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:33333 cname:Q/1HmN4Xa5NWs1ao  | [RFC5576]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=video 49203 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:video                          | [RFC5888] Video m=line     |
   |                                      | part of the BUNDLE group   |
   |                                      | with the port from audio   |
   |                                      | line repeated              |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605] - Port for RTCP  |



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   |                                      | data                       |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:44444 cname:Q/2AqlmN4Xa5NWs   | [RFC5576]                  |
   | a=ice-ufrag:85bc300d                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:bd2de4e9991c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 41:49:83:4a:99:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245] - Candidate      |
   | 192.168.1.7 49203 typ host           | lines identical with the   |
   |                                      | audio m-line.              |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                    Table 14: 5.2.7 SDP Answer w/BUNDLE

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |



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   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=mid:audio                          | [RFC5888]  - Port number   |
   |                                      | finalized as Bundle        |
   |                                      | Address.                   |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:11111 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=video 54609 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=mid:video                          | [RFC5888] - Same Bundle    |
   |                                      | address from the audio     |
   |                                      | m=line                     |



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   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:22222 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                     Table 15: 5.2.7 SDP Offer for BAS

5.2.8.  Audio, Video and Data Session

   This example show-cases SDP for negotiating a session with Audio,
   Video and data streams between Alice and Bob with
   [draft-ietf-mmusic-sdp-bundle-negotiation] support known












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title Audio, Video, Data with BUNDLE support known

Alice->Bob: Offer(Audio:Opus, Video:VP8, Data)
note right of Alice
Alice indicates BUNDLE support with identical address across all the m=lines.
end note

Bob->Alice: Answer(Audio:Opus Video:VP8, Data)
note left of Bob
Bob does the same
end note
Alice<->Bob: Two way Audio, Video and Data multiplexed

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video data      | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |



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   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ssrc:11111 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=video 54609 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=ssrc:22222 cname:Q/aoNWs11HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |



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   | m=application 54609 DTLS/SCTP 5000   | [draft-ietf-rtcweb-data-ch |
   |                                      | annel]                     |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:data                           | [RFC5888]                  |
   | a=sctpmap:5000 webrtc-DataChannel    | [draft-ietf-mmusic-sctp-sd |
   | streams=1;label="channel             | p]                         |
   | 1";subprotocol="chat";               |                            |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   +--------------------------------------+----------------------------+

                         Table 16: 5.2.8 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video data      | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice] Bob's trickle        |
   |                                      | support support is         |
   |                                      | indicated at the session   |
   |                                      | level                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |



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   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:33333 cname:L/aoNWs11HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video  49203 UDP/TLS/RTP/SAVPF 120 | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |



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   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=ssrc:44444 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=application 49203 DTLS/SCTP 5000   | [draft-ietf-mmusic-sctp-sd |
   |                                      | p]                         |
   | c=IN IP4 98.248.92.771               | [RFC4566]                  |
   | a=mid:data                           | [RFC5888]                  |
   | a=sctpmap:5000 webrtc-DataChannel    | [draft-ietf-mmusic-sctp-sd |
   | streams=16;label="channel            | p]                         |
   | 1";subprotocol="chat";               |                            |
   | a=setup:active                       | [RFC4145]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   +--------------------------------------+----------------------------+

                        Table 17: 5.2.8 SDP Answer

5.2.9.  Two-Way Audio,Video w/BUNDLE Unsupported

   This use-case illustrates SDP Offer/Answer exchange when the far-end
   (Bob) either doesn't support media bundling or doesn't want to group
   m=lines over a single 5-tuple.

   On successful Offer/Answer exchange, Alice and Bob each end up using
   unique 5-tuple for audio and video media streams respectively.




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title 2-Way Secure Audio,Video with BUNDLE Unsupported

Alice->Bob: Offer(Audio:Opus Video:VP8)
note right of Alice
Alice offers BUNDLE support with unique address for the audio and video m-line
end note

Bob->Alice: Answer(Audio:Opus Video:VP8)
note left of Bob
Bob uses unique addresses as well since he doesn't understand BUNDLE
end note

Alice <-> Bob: 2Way Call with Audio and Video on different addresses.

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 55232 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=mid:audio                          | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |



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   | a=sendrecv                           | [RFC3264]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ssrc:11111 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 55232 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 55232 typ srflx raddr  |                            |
   | 192.168.1.4 rport 55232              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 54332 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=mid:video                          | [RFC5888] Video m=line     |
   |                                      | part of the BUNDLE group   |
   |                                      | with a unique port number  |
   | a=rtcp:54721 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:22222 cname:yvY7/EocUG1f0fcg  | [RFC5576]                  |
   | a=ice-ufrag:7872093                  | [RFC5245]                  |
   | a=ice-pwd:ee3474af08a068a28a397a4c3f | [RFC5245]                  |
   | 31747d1                              |                            |
   | a=fingerprint:sha-1 6d:f7:c9:c7:70:9 | [RFC5245]                  |
   | d:1f:66:79:a8:07:99:41:49:83:4a:97:0 |                            |
   | e:1f:ef                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54332 typ host           |                            |
   | a=candidate:1 1 UDP  1694302207      | [RFC5245]                  |
   | 24.23.204.141 54332 typ srflx raddr  |                            |



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   | 192.168.1.4 rport 54332              |                            |
   | a=candidate:0 2 2113667326           | [RFC5245]                  |
   | 192.168.1.4 54721 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 24.23.204.141 54721 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54721              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                    Table 18: 5.2.9 SDP Offer w/BUNDLE

   +------------------------------------------+------------------------+
   | SDP Contents                             | RFC#/Notes             |
   +------------------------------------------+------------------------+
   | v=0                                      | [RFC4566]              |
   | o=-  16833 0 IN IP4 0.0.0.0              | [RFC4566]              |
   | s=-                                      | [RFC4566]              |
   | t=0 0                                    | [RFC4566]              |
   | a=msid-semantic:WMS                      | [MSID]                 |
   | a=ice-options:trickle                    | [draft-ivov-mmusic-tri |
   |                                          | ckle-ice]              |
   | m=audio 53214 UDP/TLS/RTP/SAVPF 109      | [RFC4566]              |
   | c=IN IP4 98.248.92.77                    | [RFC4566]              |
   | a=msid:ma ta                             | Identifies             |
   |                                          | RTCMediaStream ID (ma) |
   |                                          | and                    |
   |                                          | RTCMediaStreamTrack ID |
   |                                          | (ta)                   |
   | a=rtcp:60065 IN IP4 98.248.92.77         | [RFC3605]              |
   | a=rtpmap:109 opus/48000/2                | [draft-ietf-payload-rt |
   |                                          | p-opus]                |
   | a=extmap:1 urn:ietf:params:rtp-hdrext    | [RFC6464]              |
   | :ssrc-audio-level                        |                        |
   | a=ptime:20                               | [draft-ietf-payload-rt |
   |                                          | p-opus]                |
   | a=setup:active                           | [RFC4145] - Bob        |
   |                                          | carries out DTLS       |
   |                                          | Handshake in parallel  |
   | a=sendrecv                               | [RFC3264]              |
   | a=rtcp-fb:109 nack                       | [RFC5104]              |
   | a=ice-ufrag:c300d85b                     | [RFC5245]              |
   | a=ice-                                   | [RFC5245]              |
   | pwd:de4e99bd291c325921d5d47efbabd9a2     |                        |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e | [RFC5245]              |
   | :1f:ef:6d:f7:c9:c7:70:9d:1f:66:79:a8:07  |                        |



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   | a=candidate:0 1 UDP 2113667327           | [RFC5245]              |
   | 192.168.1.7 53214 typ host               |                        |
   | a=candidate:1 1 UDP 1694302207           | [RFC5245]              |
   | 98.248.92.77 53214 typ srflx raddr       |                        |
   | 192.168.1.7 rport 53214                  |                        |
   | a=candidate:0 2 UDP 2113667326           | [RFC5245]              |
   | 192.168.1.7 60065 typ host               |                        |
   | a=candidate:1 2 UDP 1694302206           | [RFC5245]              |
   | 98.248.92.77 60065 typ srflx raddr       |                        |
   | 192.168.1.7 rport 60065                  |                        |
   | a=rtcp-rsize                             | [RFC5506]              |
   | m=video 58679 UDP/TLS/RTP/SAVPF 120      | [RFC4566]              |
   | c=IN IP4 98.248.92.77                    | [RFC4566]              |
   | a=msid:ma tb                             | Identifies             |
   |                                          | RTCMediaStream ID (ma) |
   |                                          | and                    |
   |                                          | RTCMediaStreamTrack ID |
   |                                          | (tb)                   |
   | a=rtcp:56507 IN IP4 98.248.92.77         | [RFC3605]              |
   | a=rtpmap:120 VP8/90000                   | [draft-ietf-payload-vp |
   |                                          | 8]                     |
   | a=setup:active                           | [RFC4145] - Bob        |
   |                                          | carries out DTLS       |
   |                                          | Handshake in parallel  |
   | a=sendrecv                               | [RFC3264]              |
   | a=ice-ufrag:85bC300                      | [RFC5245]              |
   | a=ice-                                   | [RFC5245]              |
   | pwd:325921d5d47efbabd9a2de4e99bd291c     |                        |
   | a=fingerprint:sha-1 9d:1f:66:79:a8:07:99 | [RFC5245]              |
   | :41:49:83:4a:97:0e:1f:ef:6d:f7:c9:c7:70  |                        |
   | a=candidate:0 1 UDP 2113667327           | [RFC5245]              |
   | 192.168.1.7 58679 typ host               |                        |
   | a=candidate:1 1 UDP 1694302207           | [RFC5245]              |
   | 98.248.92.77 58679 typ srflx raddr       |                        |
   | 192.168.1.7 rport 58679                  |                        |
   | a=candidate:0 2 UDP 2113667326           | [RFC5245]              |
   | 192.168.1.7 56607 typ host               |                        |
   | a=candidate:1 2 UDP 1694302206           | [RFC5245]              |
   | 98.248.92.77 56607 typ srflx raddr       |                        |
   | 192.168.1.7 rport 56607                  |                        |
   | a=rtcp-fb:120 nack                       | [RFC5104]              |
   | a=rtcp-fb:120 nack pli                   | [RFC5104]              |
   | a=rtcp-fb:120 ccm fir                    | [RFC5104]              |
   | a=rtcp-rsize                             | [RFC5506]              |
   +------------------------------------------+------------------------+

                 Table 19: 5.2.9 SDP Answer without BUNDLE




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5.2.10.  Audio, Video BUNDLED but Data Not BUNDLED

   This example show-cases SDP for negotiating a session with Audio,
   Video and data streams between Alice and Bob but with data stream not
   part of the BUNDLE group.  This is shown by assigning unique port for
   data media sections.

   title Audio, Video, with Data out of BUNDLE
   Alice->Bob: Offer(Audio:Opus, Video:VP8, Data (Not in BUNDLE)
   note right of Alice
   Alice wants to multiplex audio, video but not data
   end note

   Bob->Alice: Answer(Audio:Opus Video:VP8, Data)
   note left of Bob
   Bob does the same
   end note
   Alice<->Bob: Two way Audio, Video multiplexed except Data

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | wants to BUNDLE only audio |
   |                                      | and video media.           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |



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   | a=setup:actpass                      | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ssrc:11111 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 54609 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |



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   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=ssrc:22222 cname:Q/aoNWs11HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=application 10000 DTLS/SCTP 5000   | [draft-ietf-rtcweb-data-ch |
   |                                      | annel]                     |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:data                           | [RFC5888]                  |
   | a=sctpmap:5000 webrtc-DataChannel    | [draft-ietf-mmusic-sctp-sd |
   | streams=16;label="channel            | p]                         |
   | 1";subprotocol="chat";               |                            |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=ice-ufrag:89819013                 | [RFC5245]                  |
   | a=ice-pwd:1747d1ee3474af08a068a28a39 | [RFC5245]                  |
   | 7a4c3f3                              |                            |
   | a=fingerprint:sha-1 0e:1f:ef:6d:f7:c | [RFC5245]                  |
   | 9:c7:70:99:41:49:83:4a:97:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 10000 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 10000 typ srflx raddr  |                            |
   | 192.168.1.4 rport 10000              |                            |
   +--------------------------------------+----------------------------+

                        Table 20: 5.2.10 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |



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   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:33333 cname:L/aoNWs11HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 49203 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 98.248.92.771               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |



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   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=ssrc:44444 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=application 20000 DTLS/SCTP 5000   | [draft-ietf-mmusic-sctp-sd |
   |                                      | p]                         |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:data                           | [RFC5888]                  |
   | a=sctpmap:5000 webrtc-DataChannel    | [draft-ietf-mmusic-sctp-sd |
   | streams=1;label="channel             | p]                         |
   | 1";subprotocol="chat";               |                            |
   | a=setup:active                       | [RFC4145]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=ice-ufrag:991Ca2a5e                | [RFC5245]                  |
   | a=ice-                               | [RFC5245] - Session Level  |
   | pwd:921d5d47efbabd9a2de4e99bd291c325 | ICE password               |
   | a=fingerprint:sha-1 6d:f7:c9:c7:70:9 | [RFC5245]                  |
   | d:1f:66:79:a8:07:99:41:49:83:4a:97:0 |                            |
   | e:1f:ef                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 20000 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 20000 typ srflx raddr   |                            |
   | 192.168.1.7 rport 20000              |                            |
   +--------------------------------------+----------------------------+

                        Table 21: 5.2.10 SDP Answer

5.2.11.  Audio Only then Add Video and BUNDLE

   This example involves 2 Offer/Answer exchanges.  First one setting up
   Audio-only session followed by an updated Offer/Answer exchange to
   add video stream to the ongoing session.  Also the newly added video
   stream is BUNDLED with the audio stream.





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   title Audio Only , Add Video and BUNDLE

   Alice->Bob: Offer(Audio:Opus)
   note right of Alice
   Alice indicates support for BUNDLE
   end note

   Bob->Alice: Answer(Audio:Opus)
   note left of Bob
   Bob also indicates support for BUNDLE
   end note
   Alice<->Bob: Two way Audio only session

   Alice->Bob: Updated Offer(Audio:Opus, Video:VP8)
   note right of Alice
   Alice adds video stream to BUNDLE with audio
   end note

   Bob->Alice: Updated Answer(Audio:Opus, Video:VP8)
   note left of Bob
   Bob also does the same
   end note
   Alice<->Bob: Two way Opus Audio and VP8 Video session


   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | wants to BUNDLE only audio |
   |                                      | and video media.           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |



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   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ssrc:11111 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                        Table 22: 5.2.11 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |



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   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:33333 cname:L/aoNWs11HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                        Table 23: 5.2.10 SDP Answer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=1                                  | Version number incremented |
   |                                      | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | wants to BUNDLE only audio |



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   |                                      | and video media.           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ssrc:11111 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 54609 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |



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   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=ssrc:22222 cname:Q/aoNWs11HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                    Table 24: 5.2.11 SDP Updated Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=1                                  | [RFC4566] Version number   |
   |                                      | incremented                |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio video           | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |



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   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:33333 cname:L/aoNWs11HmN4Xa5  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 49203 UDP/TLS/RTP/SAVPF 120  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:video                          | [RFC5888]                  |
   | a=rtpmap:120 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |



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   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-fb:120 nack                   | [RFC5104]                  |
   | a=rtcp-fb:120 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:120 ccm fir                | [RFC5104]                  |
   | a=ssrc:44444 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                    Table 25: 5.2.11 SDP Updated Answer

5.3.  MultiResolution, RTX, FEC Examples

   This section deals with scenarios related to multiresolution
   negotiation such as layered coding, simulcast, along with techniques
   that deal with providing robustness against transmission errors such
   as FEC and RTX.  Also to note, meachnisms such as FEC and RTX could
   be envisioned in the above basic scenarios as well.

5.3.1.  Sendonly Simulcast w/2 cameras and 2 encodings per camera

   This SDP below shows Offer/Answer exchange with an audio and two
   video streams each of which can be sent at two different resolutions.

   One video stream supports VP8, while the other supports H.264.

   bundle-only framework is used along with BUNDLE grouping framework to
   enable multiplexing of all the 5 streams (1 audio stream + 4 video
   streams) over a single RTP Session.

title 1 Way Successful Simulcast w/BUNDLE

note right of Alice
Alice offers 2 sendonly video streams with 2 simulcast encodings per stream
end note
Alice->Bob: Offer(Audio:Opus,Video1:VP8,Video2:H.264) with bundle-only for video
note left of Bob
Bob accepts Alice's offer and 2 encodings per stream
end note
Alice->Bob: One-Way 1 Opus, 2 H.264 and 2 VP8 video streams, all mulitplexed



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   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1 m2              | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendonly                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ssrc:11111 EocUG1f0fcg             | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |



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   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100   | bundle-only video line     |
   |                                      | with port number set to    |
   |                                      | zero                       |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:100 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=imageattr:98 [x=1280,y=720]        | [RFC6236]Camera-1,Encoding |
   |                                      | -1 Resolution              |
   | a=fmtp:98 max-fr=30                  | [RFC4566]                  |
   | a=imageattr:100 [x=640,y=480]        | [RFC6236]                  |
   |                                      | Camera-1,Encoding-2        |
   |                                      | Resolution                 |
   | a=fmtp:100 max-fr=15                 | [RFC4566]                  |
   | a=simulcast: send 98;100             | [draft-westerlund-avtcore- |
   |                                      | rtp-simulcast]             |
   | a=ssrc:12345 cname:axzo1278npDlAzM73 | [RFC5576] [draft-rescorla- |
   |                                      | avtcore-6222bis]           |
   |                                      | Camera-1,Encoding-1 SSRC   |
   |                                      | with Session CNAME         |
   | a=ssrc:45678 cname:axzo1278npDlAzM73 | [RFC5576] [draft-rescorla- |
   |                                      | avtcore-6222bis]           |
   |                                      | Camera-1,Encoding-2 SSRC   |
   |                                      | with Session CNAME         |
   | a=sendonly                           | [RFC3264] - Send only      |
   |                                      | video stream               |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-fb:98 nack                    | [RFC5104]                  |
   | a=rtcp-fb:98 nack pli                | [RFC5104]                  |
   | a=rtcp-fb:98 ccm fir                 | [RFC5104]                  |
   | a=rtcp-fb:100 nack                   | [RFC5104]                  |
   | a=rtcp-fb:100 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:100 ccm fir                | [RFC5104]                  |



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   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 0 UDP/TLS/RTP/SAVPF 101 102  | bundle-only video line     |
   |                                      | with port number set to    |
   |                                      | zero                       |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tc                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tc)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m2                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:101 H264/90000              | [RFC3984]                  |
   | a=rtpmap:102 H264/90000              | [RFC3984]                  |
   | a=fmtp:101 profile-level-id=4d0028   | [RFC3984]Camera-2,Encoding |
   | ;packetization-mode=1;max-fr=30      | -1 Resolution              |
   | a=fmtp:102 profile-level-id=4d0028   | [RFC3984]Camera-1,Encoding |
   | ;packetization-mode=1;max-fr=15      | -2 Resolution              |
   | a=simulcast: send 101;102            | [draft-westerlund-avtcore- |
   |                                      | rtp-simulcast]             |
   | a=ssrc:67890 cname:axzo1278npDlAzM73 | [RFC5576] [draft-rescorla- |
   |                                      | avtcore-6222bis]           |
   |                                      | Camera-1,Encoding-1 SSRC   |
   |                                      | with Session CNAME         |
   | a=ssrc:56789 cname:axzo1278npDlAzM73 | [RFC5576] [draft-rescorla- |
   |                                      | avtcore-6222bis]           |
   |                                      | Camera-1,Encoding-2 SSRC   |
   |                                      | with Session CNAME         |
   | a=sendonly                           | [RFC3264] - Send only      |
   |                                      | video stream               |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-fb:101 nack                   | [RFC5104]                  |
   | a=rtcp-fb:101 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:101  ccm fir               | [RFC5104]                  |
   | a=rtcp-fb:102 nack                   | [RFC5104]                  |
   | a=rtcp-fb:102 nack pli               | [RFC5104]                  |
   | a=rtcp-fb:102 ccm fir                | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                         Table 26: 5.3.1 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |



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   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1 m2              | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=sendonly                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:22222                         | [RFC5576]                  |
   | cname:y8/C90alEocUG1f0fcg            |                            |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.4 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 64678 typ host           |                            |



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   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.4 rport 60065              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 49203 UDP/TLS/RTP/SAVPF 98   | BUNDLE accepted with port  |
   | 100                                  | repeated from the audio    |
   |                                      | port                       |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:100 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=imageattr:98 [x=1280,y=720]        | [RFC6236]Camera-1,Encoding |
   |                                      | -1 Resolution              |
   | a=fmtp:98 max-fr=30                  | [RFC4566]                  |
   | a=imageattr:100 [x=640,y=480]        | [RFC6236]                  |
   |                                      | Camera-1,Encoding-2        |
   |                                      | Resolution                 |
   | a=fmtp:100 max-fr=15                 | [RFC4566]                  |
   | a=recvonly                           | [RFC3264] - receive only   |
   |                                      | video stream               |
   | a=simulcast: recv 98;100             | [draft-westerlund-avtcore- |
   |                                      | rtp-simulcast]             |
   | a=ssrc:54321 cname:axzo1278npDlAzM73 | [RFC5576]                  |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.4 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.4 rport 60065              |                            |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |



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   | a=rtcp-mux                           | [RFC5576]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 54609 UDP/TLS/RTP/SAVPF 101  | BUNDLE accepted with port  |
   | 102                                  | repeated from the audio    |
   |                                      | port                       |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=rtcp:56503 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=msid:ma tc                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tc)                       |
   | a=mid:m2                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:101 H264/90000              | [RFC3984]                  |
   | a=rtpmap:102 H264/90000              | [RFC3984]                  |
   | a=recvonly                           | [RFC3264] - Send only      |
   |                                      | video stream               |
   | a=fmtp:101 profile-level-id=4d0028   | [RFC3984]Camera-2,Encoding |
   | ;packetization-mode=1;max-fr=30      | -1 Resolution              |
   | a=fmtp:102 profile-level-id=4d0028   | [RFC3984]Camera-1,Encoding |
   | ;packetization-mode=1;max-fr=15      | -2 Resolution              |
   | a=simulcast: recv 101;102            | [draft-westerlund-avtcore- |
   |                                      | rtp-simulcast]             |
   | a=ssrc:90876 cname:axzo1278npDlAzM73 | [RFC5576]                  |
   | a=ice-ufrag:ufrag:c300d85b           | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5576]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |



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   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                         Table 27: 5.3.1 SDP Anwer

5.3.2.  Successful SVC Video Stream

   This section shows an SDP Offer/Answer for a session with an audio
   and a single video stream.  The video stream is layered coding at 3
   different resolutions based on [RFC5583].  The video m=line shows 3
   streams with last stream (payload 100) dependent on streams with
   payload 96 and 97 for decoding.

  title SVC Session - 3 Layers w/BUNDLE
  note right of Alice
  Alice offers 3 sendonly video stream with 3 layers of SVC
  end note
  Alice->Bob: Offer(Audio:Opus Video: H.264 SVC) bundle-only
  note left of Bob
  Bob accepts Alice's Offered Codec operation points
  end note
  Bob->Alice: Answer(Video: H.264) bundle-only
  Alice->Bob: One-Way H.264 Video with codec points as indicated by Bob.


   +---------------------------------------+---------------------------+
   | SDP Contents                          | RFC#/Notes                |
   +---------------------------------------+---------------------------+
   | v=0                                   | [RFC4566]                 |
   | o=- 20519 0 IN IP4 0.0.0.0            | [RFC4566]                 |
   | s=-                                   | [RFC4566]                 |
   | t=0 0                                 | [RFC4566]                 |
   | a=msid-semantic:WMS                   | [MSID]                    |
   | a=group:BUNDLE m0 m1                  | [draft-ietf-mmusic-sdp-bu |
   |                                       | ndle-negotiation] Alice   |
   |                                       | supports grouping of      |
   |                                       | m=lines under BUNDLE      |
   |                                       | semantics                 |
   | a=ice-options:trickle                 | [draft-ivov-mmusic-trickl |
   |                                       | e-ice]                    |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109   | [RFC4566]                 |
   | c=IN IP4 24.23.204.141                | [RFC4566]                 |
   | a=msid:ma ta                          | Identifies RTCMediaStream |
   |                                       | ID (ma) and               |
   |                                       | RTCMediaStreamTrack ID    |
   |                                       | (ta)                      |
   | a=rtcp:64678 IN IP4 24.23.204.141     | [RFC3605]                 |
   | a=mid:m0                              | [RFC5888] Audio m=line    |



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   |                                       | part of BUNDLE group with |
   |                                       | a unique port number      |
   | a=rtpmap:109 opus/48000/2             | [draft-ietf-payload-rtp-o |
   |                                       | pus]                      |
   | a=extmap:1 urn:ietf:params:rtp-hdrext | [RFC6464]                 |
   | :ssrc-audio-level                     |                           |
   | a=ptime:20                            | [draft-ietf-payload-rtp-o |
   |                                       | pus]                      |
   | a=sendonly                            | [RFC3264]                 |
   | a=rtcp-fb:109 nack                    | [RFC5104]                 |
   | a=setup:actpass                       | [RFC4145] - Alice can     |
   |                                       | perform DTLS before       |
   |                                       | Answer arrives            |
   | a=rtcp-mux                            | [RFC5761]                 |
   | a=ice-ufrag:074c6550                  | [RFC5245]                 |
   | a=ice-                                | [RFC5245]                 |
   | pwd:a28a397a4c3f31747d1ee3474af08a068 |                           |
   | a=fingerprint:sha-1 99:41:49:83:4a:97 | [RFC5245]                 |
   | :0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:79: |                           |
   | a8:07                                 |                           |
   | a=candidate:0 1 UDP  2113667327       | [RFC5245]                 |
   | 192.168.1.4 54609 typ host            |                           |
   | a=candidate:1 1 UDP  694302207        | [RFC5245]                 |
   | 24.23.204.141 54609 typ srflx raddr   |                           |
   | 192.168.1.4 rport 54609               |                           |
   | a=candidate:0 2 UDP 2113667326        | [RFC5245]                 |
   | 192.168.1.4 64678 typ host            |                           |
   | a=candidate:1 2 UDP  1694302206       | [RFC5245]                 |
   | 24.23.204.141 64678 typ srflx raddr   |                           |
   | 192.168.1.4 rport 64678               |                           |
   | a=ssrc:67890 cname:axzo1278npDlAzM73  | [RFC5576]                 |
   | a=rtcp-rsize                          | [RFC5506]                 |
   | m=video 0 UDP/TLS/RTP/SAVPF 96 97 100 | bundle-only video line    |
   |                                       | with port number set to   |
   |                                       | zero                      |
   | c=IN IP4 24.23.204.141                | [RFC4566]                 |
   | a=msid:ma tb                          | Identifies RTCMediaStream |
   |                                       | ID (ma) and               |
   |                                       | RTCMediaStreamTrack ID    |
   |                                       | (tc)                      |
   | a=rtcp:64678 IN IP4 24.23.204.141     | [RFC3605]                 |
   | a=mid:m1                              | [RFC5888] Audio m=line    |
   |                                       | part of BUNDLE group      |
   | a=msid:ma tb                          |                           |
   | a=rtpmap:96 H264/90000                | [RFC3984]                 |
   | a=fmtp:96 profile-level-id=4d0028     | [RFC3984]H.264 Layer 1    |
   | ;packetization-mode=1;max-fr=30;max-  |                           |
   | fs=8040                               |                           |



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   | a=rtpmap:97 H264/90000                | [RFC3984]                 |
   | a=fmtp:97 profile-level-id=4d0028     | [RFC3984] H.264 Layer 2   |
   | ;packetization-mode=1;max-fr=15;max-  |                           |
   | fs=1200                               |                           |
   | a=rtpmap:100 H264-SVC/90000           | [RFC3984]                 |
   | a=fmtp:100 profile-level-id=4d0028    | [RFC3984]                 |
   | ;packetization-mode=1;max-fr=30;max-  |                           |
   | fs=8040                               |                           |
   | a=depend:100 lay m1:96,97;            | [RFC5583]Layer 3          |
   |                                       | dependent on layers 1 and |
   |                                       | 2                         |
   | a=sendonly                            | [RFC3264] - Send only     |
   |                                       | video stream              |
   | a=rtcp-mux                            | [RFC5761]                 |
   | a=bundle-only                         | [draft-roach-mmusic-unifi |
   |                                       | ed-plan]                  |
   | a=ssrc:1732846380                     | [RFC5576]                 |
   | cname:axzo1278npDlAzM73               |                           |
   | a=ssrc:1732846381                     | [RFC5576]                 |
   | cname:axzo1278npDlAzM73               |                           |
   | a=ssrc:1732846382                     | [RFC5576]                 |
   | cname:axzo1278npDlAzM73               |                           |
   | a=rtcp-fb:* nack                      | [RFC5104]                 |
   | a=rtcp-fb:* nack pli                  | [RFC5104]                 |
   | a=rtcp-fb:* ccm fir                   | [RFC5104]                 |
   | a=rtcp-rsize                          | [RFC5506]                 |
   +---------------------------------------+---------------------------+

                    Table 28: 5.3.2 SDP Offer with SVC

   +---------------------------------------+---------------------------+
   | SDP Contents                          | RFC#/Notes                |
   +---------------------------------------+---------------------------+
   | v=0                                   | [RFC4566]                 |
   | o=- 20519 0 IN IP4 0.0.0.0            | [RFC4566]                 |
   | s=-                                   | [RFC4566]                 |
   | t=0 0                                 | [RFC4566]                 |
   | a=msid-semantic:WMS                   | [MSID]                    |
   | a=group:BUNDLE m0 m1                  | [draft-ietf-mmusic-sdp-bu |
   |                                       | ndle-negotiation] Alice   |
   |                                       | supports grouping of      |
   |                                       | m=lines under BUNDLE      |
   |                                       | semantics                 |
   | a=ice-options:trickle                 | [draft-ivov-mmusic-trickl |
   |                                       | e-ice]                    |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109   | [RFC4566]                 |
   | c=IN IP4 98.248.92.77                 | [RFC4566]                 |
   | a=msid:ma ta                          | Identifies RTCMediaStream |



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   |                                       | ID (ma) and               |
   |                                       | RTCMediaStreamTrack ID    |
   |                                       | (ta)                      |
   | a=rtcp:60065 IN IP4 98.248.92.77      | [RFC3605]                 |
   | a=mid:m0                              | [RFC5888] Audio m=line    |
   |                                       | part of BUNDLE group with |
   |                                       | a unique port number      |
   | a=rtpmap:109 opus/48000/2             | [draft-ietf-payload-rtp-o |
   |                                       | pus]                      |
   | a=extmap:1 urn:ietf:params:rtp-hdrext | [RFC6464]                 |
   | :ssrc-audio-level                     |                           |
   | a=ptime:20                            | [draft-ietf-payload-rtp-o |
   |                                       | pus]                      |
   | a=rtcp-fb:109 nack                    | [RFC5104]                 |
   | a=recvonly                            | [RFC3264]                 |
   | a=setup:active                        | [RFC4145] - Bob carries   |
   |                                       | out DTLS Handshake in     |
   |                                       | parallel                  |
   | a=rtcp-mux                            | [RFC5761]                 |
   | a=ice-ufrag:074c6550                  | [RFC5245]                 |
   | a=ice-                                | [RFC5245]                 |
   | pwd:a28a397a4c3f31747d1ee3474af08a068 |                           |
   | a=fingerprint:sha-1 99:41:49:83:4a:97 | [RFC5245]                 |
   | :0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:79: |                           |
   | a8:07                                 |                           |
   | a=candidate:0 1 UDP  2113667327       | [RFC5245]                 |
   | 192.168.1.7 54609 typ host            |                           |
   | a=candidate:1 1 UDP  694302207        | [RFC5245]                 |
   | 98.248.92.77 49203 typ srflx raddr    |                           |
   | 192.168.1.5 rport 49203               |                           |
   | a=candidate:0 2 UDP 2113667326        | [RFC5245]                 |
   | 192.168.1.7 60065 typ host            |                           |
   | a=candidate:1 2 UDP  1694302206       | [RFC5245]                 |
   | 98.248.92.77 60065 typ srflx raddr    |                           |
   | 192.168.1.5 rport 60065               |                           |
   | a=rtcp-rsize                          | [RFC5506]                 |
   | m=video 54609 UDP/TLS/RTP/SAVPF 96    | BUNDLE accepted Bundle    |
   | 100                                   | address same as audio     |
   |                                       | m=line.                   |
   | c=IN IP4 98.248.92.77                 | [RFC4566]                 |
   | a=msid:ma tb                          | Identifies RTCMediaStream |
   |                                       | ID (ma) and               |
   |                                       | RTCMediaStreamTrack ID    |
   |                                       | (tb)                      |
   | a=rtcp:56503 IN IP4 98.248.92.77      | [RFC3605]                 |
   | a=mid:m1                              | [RFC5888] Video m=line    |
   |                                       | part of BUNDLE group      |
   | a=rtpmap:96 H264/90000                | [RFC3984]                 |



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   | a=fmtp:96 profile-level-id=4d0028     | [RFC3984]H.264 Layer 1    |
   | ;packetization-mode=1;max-fr=30;max-  |                           |
   | fs=8040                               |                           |
   | a=rtpmap:100 H264-SVC/90000           | [RFC3984]                 |
   | a=fmtp:100 profile-level-id=4d0028    | [RFC3984]                 |
   | ;packetization-mode=1;max-fr=30;max-  |                           |
   | fs=8040                               |                           |
   | a=depend:100 lay m1:96;               | [RFC5583] Bob chooses 2   |
   |                                       | Codec Operation points    |
   | a=ice-ufrag:074c6550                  | [RFC5245]                 |
   | a=ice-                                | [RFC5245]                 |
   | pwd:a28a397a4c3f31747d1ee3474af08a068 |                           |
   | a=fingerprint:sha-1 99:41:49:83:4a:97 | [RFC5245]                 |
   | :0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:79: |                           |
   | a8:07                                 |                           |
   | a=candidate:0 1 UDP  2113667327       | [RFC5245]                 |
   | 192.168.1.5 54609 typ host            |                           |
   | a=candidate:1 1 UDP  694302207        | [RFC5245]                 |
   | 24.23.204.142 54609 typ srflx raddr   |                           |
   | 192.168.1.5 rport 54609               |                           |
   | a=candidate:0 2 UDP 2113667326        | [RFC5245]                 |
   | 192.168.1.5 64678 typ host            |                           |
   | a=candidate:1 2 UDP  1694302206       | [RFC5245]                 |
   | 24.23.204.142 64678 typ srflx raddr   |                           |
   | 192.168.1.5 rport 64678               |                           |
   | a=recvonly                            | [RFC3264] - Receive only  |
   |                                       | video stream              |
   | a=setup:active                        | [RFC4145] - Bob carries   |
   |                                       | out DTLS Handshake in     |
   |                                       | parallel                  |
   | a=rtcp-mux                            | [RFC5761]                 |
   | a=bundle-only                         | [draft-roach-mmusic-unifi |
   |                                       | ed-plan]                  |
   | a=ssrc:4638117328                     | [RFC5576]                 |
   | cname:axzo1278npDlAzM73               |                           |
   | a=rtcp-rsize                          | [RFC5506]                 |
   +---------------------------------------+---------------------------+

                    Table 29: 5.3.2 SDP Answer with SVC

5.3.3.  Successful Simulcast Video Streams with Retransmisson

   This section shows an SDP Offer/Answer exchange for a simulcast
   scenario with 2 two resolutions and has [RFC4588] style re-
   transmission flows.






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title Simulcast Streams with Retransmission

note right of Alice
Alice offers single audio and simulcasted video stream
end note
Alice->Bob: Offer(Audio:Opus Video:VP8 with 2 resolutions and RTX Stream) bundle-only
note left of Bob
Bob accepts all the streams offered by Alice
end note

Bob->Alice: Answer(Audio:Opus Video:VP8 with 2 resolutions and RTX Stream) bundle-only

Alice<->Bob: 2 Way Audio and Simulcast Video with RTX Streams

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |



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   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:11111 cname:EocUG1f0fcg/yvY7  | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100   | bundle-only video line     |
   | 101 103                              | with port number set to    |
   |                                      | zero                       |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:100 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=rtpmap:101 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=rtpmap:103 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=fmtp:98 max-fr=30;max-fs=8040      | [RFC4566]                  |
   | a=fmtp:100 max-fr=15;max-fs=1200     | [RFC4566]                  |
   | a=fmtp:101 apt=98;rtx-time=3000      | [RFC4588]                  |
   | a=fmtp:103 apt=100;rtx-time=3000     | [RFC4588]                  |
   | a=simulast: send 98;100              | [draft-westerlund-avtcore- |
   |                                      | rtp-simulcast]             |
   | a=ssrc-group:FID 12345 34567         | [RFC5888]                  |
   | a=ssrc-group:FID 78990 90887         | [RFC5888]                  |
   | a=ssrc:12345 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:78990 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:34567 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:90887 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |



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   | a=sendrecv                           | [RFC3264]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=rtcp-fb:* nack pli                 | [RFC5104]                  |
   | a=rtcp-fb:* ccm fir                  | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                Table 30: 5.3.3 SDP Offer w/Simulcast, RTX

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:33333 cname:L/HmN4Xa5NWs1ao1  | [RFC5576]                  |



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   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 54609 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.77 64678 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 49203 UDP/TLS/RTP/SAVPF 98   | BUNDLE accepted with       |
   | 100 101 103                          | Bundle address identical   |
   |                                      | to audio m-line            |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:100 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=rtpmap:101 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=rtpmap:103 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=fmtp:98 max-fr=30;max-fs=8040      | [RFC4566]                  |
   | a=fmtp:100 max-fr=15;max-fs=1200     | [RFC4566]                  |
   | a=fmtp:101 apt=98;rtx-time=3000      | [RFC4588]                  |
   | a=fmtp:103 apt=100;rtx-time=3000     | [RFC4588]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |



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   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.772 60065 typ srflx raddr  |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=simulcast: recv 98;100             | [draft-westerlund-avtcore- |
   |                                      | rtp-simulcast]             |
   | a=ssrc-group:FID 54321 88776         | [RFC5888]                  |
   | a=ssrc-group:FID 77656 12908         | [RFC5888]                  |
   | a=ssrc:54321 cname:LP/NWs1ao1HmN4Xa5 | [RFC5576]                  |
   | a=ssrc:77656 cname:LP/NWs1ao1HmN4Xa5 | [RFC5576]                  |
   | a=ssrc:88776 cname:LP/NWs1ao1HmN4Xa5 | [RFC5576]                  |
   | a=ssrc:12908 cname:LP/NWs1ao1HmN4Xa5 | [RFC5576]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=rtcp-fb:* nack pli                 | [RFC5104]                  |
   | a=rtcp-fb:* ccm fir                  | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                Table 31: 5.3.3 SDP Answer w/Simulcast, RTX

5.3.4.  Successful 1-way Simulcast with 2 resolutions and RTX - One
        resolution rejected

   This section shows an SDP Offer/Answer exchange for a simulcast
   scenario with 2 two resolutions and has [RFC4588] style re-
   transmission flows.

   It also showcases when Bob rejects one of the Simulcast Video Stream
   which results in the rejection of the associated repair stream
   implicitly














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title Simulcast Streams with Retransmission Rejected

note right of Alice
Alice offers sendonly single audio and simulcasted video stream.
end note
Alice->Bob: Offer(Audio:Opus Video:VP8 with 2 resolutions and RTX Streams) bundle-only

note left of Bob
Bob accepts one simulcast,rtx and rejects the other
end note
Bob->Alice: Answer(Audio:Opus Video:VP8 with 1 resolution and the RTX Stream) bundle-only

Alice->Bob: 1 Way Audio, Video Session
note right of Alice
Only 1 Video stream and its associated RTX stream
is sent to Bob
end note


   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |



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   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=sendonly                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:11111 cname:LP/NWs1ao1HmN4Xa5 | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100   | bundle-only video line     |
   | 101 103                              | with port number set to    |
   |                                      | zero                       |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:100 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=rtpmap:101 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=rtpmap:103 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=fmtp:98 max-fr=30;max-fs=8040      | [RFC4566]                  |
   | a=fmtp:100 max-fr=15;max-fs=1200     | [RFC4566]                  |
   | a=fmtp:101 apt=98;rtx-time=3000      | [RFC4588]                  |
   | a=fmtp:103 apt=100;rtx-time=3000     | [RFC4588]                  |
   | a=simulcast: send 98;100             | [draft-westerlund-avtcore- |
   |                                      | rtp-simulcast]             |
   | a=ssrc-group:FID 12345 34567         | [RFC5888]                  |



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   | a=ssrc-group:FID 78990 90887         | [RFC5888]                  |
   | a=ssrc:12345 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:78990 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:34567 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:90887 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=sendonly                           | [RFC3264]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=rtcp-fb:* nack pli                 | [RFC5104]                  |
   | a=rtcp-fb:* ccm fir                  | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                Table 32: 5.3.4 SDP Offer w/Simulcast, RTX

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:49203 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |



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   | a=recvonly                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 49203 UDP/TLS/RTP/SAVPF 98   | BUNDLE accepted with       |
   | 101                                  | Bundle address identical   |
   |                                      | to audio m-line            |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:101 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=fmtp:98 max-fr=30;max-fs=8040      | [RFC4566]                  |
   | a=fmtp:101 apt=98;rtx-time=3000      | [RFC4588]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.5 rport 49203              |                            |



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   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.5 rport 60065              |                            |
   | a=simulcast: recv 98                 | [draft-westerlund-avtcore- |
   |                                      | rtp-simulcast]             |
   | a=ssrc:54321 cname:NWs1ao1HmN4Xa5    | [RFC5576]                  |
   | a=recvonly                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                  Table 33: 5.3.4 SDP Answer no Simulcast

5.3.5.  Simulcast Video Stream with Forward Error Correction

   This section shows an SDP Offer/Answer exchange for Simulcast video
   stream at two resolutions and and has [RFC5956] style FEC flows.

   On completion of Offer/Answer exchange we end up one audio stream, 2
   simulcast video streams and 2 associated FEC streams are sent over a
   single 5-tuple.

title Simulcast Streams with Forward Error Correction

note right of Alice
Alice offers sendonly single audio and simulcasted video stream
end note
Alice->Bob: Offer(Audio:Opus Video:VP8 with 2 resolutions with FEC Streams) bundle-only

note left of Bob
Bob accepts simulcast stream as well as FEC streams
end note
Bob->Alice: Answer(Audio:Opus Video:VP8 with 2 resolutions with FEC Streams) bundle-only

Alice->Bob: 1 Way Audio, Video Session
note right of Alice
Successful Session with 4 video streams (Simulcast + FEC) and 1 Audio Stream

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+



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   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:11111 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |



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   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100   | bundle-only video line     |
   | 101 103                              | with port number set to    |
   |                                      | zero                       |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:100 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=rtpmap:101 1d-interleaved-         | [RFC5956]                  |
   | parityfec/90000                      |                            |
   | a=rtpmap:103 1d-interleaved-         | [RFC5956]                  |
   | parityfec/90000                      |                            |
   | a=fmtp:98 max-fr=30;max-fs=8040      | [RFC4566]                  |
   | a=fmtp:100 max-fr=15;max-fs=1200     | [RFC4566]                  |
   | a=fmtp:101 L=5; D=10; repair-        | [RFC5956]                  |
   | window=200000                        |                            |
   | a=fmtp:103 L=5; D=10; repair-        | [RFC5956]                  |
   | window=200000                        |                            |
   | a=ssrc-group:SIMULCAST 12345 78990   | Simulcast group            |
   | a=ssrc-group:FEC-FR 12345 34567      | [RFC5888]                  |
   | a=ssrc-group:FEC-FR 78990 90887      | [RFC5888]                  |
   | a=ssrc:12345 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:78990 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:34567 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=ssrc:90887 cname:Q/NWs1ao1HmN4Xa5  | [RFC5576]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=rtcp-fb:* nack pli                 | [RFC5104]                  |
   | a=rtcp-fb:* ccm fir                  | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                         Table 34: 5.3.5 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |



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   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ssrc:33333 cname:Y9/cZke09JAtpl98  | [RFC5576]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |



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   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 49203 UDP/TLS/RTP/SAVPF 98   | BUNDLE accepted with       |
   | 100 101 103                          | Bundle Address identical   |
   |                                      | to audio m=line.           |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:100 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=rtpmap:101 1d-interleaved-         | [RFC5956]                  |
   | parityfec/90000                      |                            |
   | a=rtpmap:103 1d-interleaved-         | [RFC5956]                  |
   | parityfec/90000                      |                            |
   | a=fmtp:98 max-fr=30;max-fs=8040      | [RFC4566]                  |
   | a=fmtp:100 max-fr=15;max-fs=1200     | [RFC4566]                  |
   | a=fmtp:101 L=5; D=10; repair-        | [RFC5956]                  |
   | window=200000                        |                            |
   | a=fmtp:103 L=5; D=10; repair-        | [RFC5956]                  |
   | window=200000                        |                            |
   | a=ssrc-group:SIMULCAST 54321 77656   | Simulcast group            |
   | a=ssrc-group:FEC-FR 54321 88776      | [RFC5888]                  |
   | a=ssrc-group:FEC-FR 77656 12908      | [RFC5888]                  |
   | a=ssrc:54321 cname:Q/1HmN4Xa5CClapa  | [RFC5576]                  |
   | a=ssrc:77656 cname:Q/1HmN4Xa5CClapa  | [RFC5576]                  |
   | a=ssrc:88776 cname:Q/1HmN4Xa5CClapa  | [RFC5576]                  |
   | a=ssrc:12908 cname:Q/1HmN4Xa5CClapa  | [RFC5576]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |



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   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=rtcp-fb:* nack pli                 | [RFC5104]                  |
   | a=rtcp-fb:* ccm fir                  | [RFC5104]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                        Table 35: 5.3.5 SDP Answer

5.4.  Others

   The examples in the section provide SDP for a variety of scenarios
   related to RTP Header extension, Legacy Interop scenarios and more.

5.4.1.  Audio Session - Voice Activity Detection

   This example shows Alice indicating the support of the RTP header
   extension to include the audio-level of the audio sample carried in
   the RTP packet.

   title 2-Way Audio with VAD

   Alice->Bob: Offer(Audio:Opus,PCMU,PCMA)
   note right of Alice
   Alice indicates support for including audio-level
   end note
   Bob->Alice: Answer(Audio:Opus,PCMU,PCMA)
   note left of Bob
   Bob accepts and indicates his support as well
   end note
   Alice<->Bob: Two-way Opus Audio
   note right of Alice
    Per packet audio-level is included in the RTP header.
   end note

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |



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   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | 0 8                                  |                            |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtpmap:0 PCMU/8000                 | [RFC3551]                  |
   | a=rtpmap:0 PCMA/8000                 | [RFC3551]                  |
   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145]                  |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=ssrc:11111                         | [RFC5576]                  |
   | cname:QCL/1HmN4Xa5CClapa             |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |



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   +--------------------------------------+----------------------------+

                         Table 36: 5.4.1 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | 0 98                                 |                            |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Bob accepts only     |
   |                                      | Opus Codec                 |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtpmap:0 PCMU/8000                 | [RFC3551] PCMU Audio Codec |
   | a=rtpmap:0 PCMA/8000                 | [RFC3551] PCMA Audio Codec |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=sendrecv                           | [RFC3264] - Bob can send   |
   |                                      | and recv audio             |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761] - Bob can        |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 49203                 |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |



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   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:1732846380                    | [RFC5576]                  |
   | cname:EocUG1f0fcg/yvY7               |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                        Table 37: 5.4.1 SDP Answer

5.4.2.  Audio Conference - Voice Activity Detection

   This example shows SDP for RTP header extension that allows RTP-level
   mixers in audio conferences to deliver information about the audio
   level of individual participants.

title Audio Conference with VAD Support

Alice->Mixer: Offer(Audio:Opus,PCMU,PCMA)
note right of Alice
Alice indicates its interest to audio levels for the contributing sources
end note
Mixer->Alice: Answer(Audio:Opus,PCMU,PCMA)
note left of Bob
Mixer indicates it can provide audio-levels per CSRC
end note
Alice<->Mixer: Two-way Opus Audio
note right of Alice
 Audio levels per CSRC is included in the RTP Header
end note

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20518 0 IN IP4 0.0.0.0           | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |



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   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | 0 8                                  |                            |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=extmap:1/recvonly urn:ietf:params  | [RFC6465]                  |
   | :rtp-hdrext:csrc-audio-level         |                            |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus Codec 48khz, 2  |
   |                                      | channels                   |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us] - Opus packetization   |
   |                                      | of 20ms                    |
   | a=rtpmap:0 PCMU/8000                 | [RFC3551] PCMU Audio Codec |
   | a=rtpmap:0 PCMA/8000                 | [RFC3551] PCMA Audio Codec |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=sendrecv                           | [RFC3264] - Alice can send |
   |                                      | and recv audio             |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761] - Alice can      |
   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 54609                 |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |



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   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=ssrc:11111                         | [RFC5576]                  |
   | cname:QCL/1HmN4Xa5CClapa             |                            |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                         Table 38: 5.4.2 SDP Offer

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=-  16833 0 IN IP4 0.0.0.0          | [RFC4566] - Session Origin |
   |                                      | Information                |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE audio                 | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation]           |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | 0 98                                 |                            |
   | c=IN IP4 98.248.92.77                | [RFC4566]                  |
   | a=mid:audio                          | [RFC5888]                  |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtcp:60065 IN IP4 98.248.92.77     | [RFC3605]                  |
   | a=extmap:1/sendonly urn:ietf:params  | [RFC6465]                  |
   | :rtp-hdrext:csrc-audio-level         |                            |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us] - Bob accepts only     |
   |                                      | Opus Codec                 |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtpmap:0 PCMU/8000                 | [RFC3551] PCMU Audio Codec |
   | a=rtpmap:0 PCMA/8000                 | [RFC3551] PCMA Audio Codec |
   | a=rtcp-fb:* nack                     | [RFC5104]                  |
   | a=sendrecv                           | [RFC3264] - Bob can send   |
   |                                      | and recv audio             |
   | a=setup:active                       | [RFC4145] - Bob carries    |
   |                                      | out DTLS Handshake in      |
   |                                      | parallel                   |
   | a=rtcp-mux                           | [RFC5761] - Bob can        |



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   |                                      | perform RTP/RTCP Muxing on |
   |                                      | port 49203                 |
   | a=ice-ufrag:c300d85b                 | [RFC5245]                  |
   | a=ice-                               | [RFC5245]                  |
   | pwd:de4e99bd291c325921d5d47efbabd9a2 |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP 2113667327       | [RFC5245]                  |
   | 192.168.1.7 49203 typ host           |                            |
   | a=candidate:1 1 UDP 1694302207       | [RFC5245]                  |
   | 98.248.92.77 49203 typ srflx raddr   |                            |
   | 192.168.1.7 rport 49203              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.7 60065 typ host           |                            |
   | a=candidate:1 2 UDP 1694302206       | [RFC5245]                  |
   | 98.248.92.77 60065 typ srflx raddr   |                            |
   | 192.168.1.7 rport 60065              |                            |
   | a=ssrc:2222 cname:HmN4Xa5CC/lapa     | [RFC5576]                  |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                        Table 39: 5.4.2 SDP Answer

5.4.3.  Successful legacy Interop Fallaback with bundle-only

   In the scenario described below, Alice is a multi-stream capable
   WebRTC endpoint while Bob is a legacy VOIP end-point.  The SDP Offer/
   Answer exchange demonstrates successful session setup with fallback
   to audio only stream negotiated via bundle-only framework between the
   end-points.  Specifically,

   o  Offer from Alice describes 2 cameras via 2 video m=lines with both
      marked as bundle-only.

   o  Since Bob doesnot recognize either BUNDLE mechanism or bundle-only
      attribute, he accepts only the audio stream from Alice.














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title Successful 2-Way WebRTC <-> VOIP Interop

note right of Alice
Alice is a multistream capable WebRTC end-point & Bob is behind a legacy VOIP system
end note
Alice->Bob: Offer(Audio:Opus Video: 2 VP8, 2 H2.64 Streams) with bundle-only offer
note right of Alice
Alice marks both the video streams as bundle-only
end note
Bob->Alice: Answer(Audio:Opus)
note left of Bob
 Bob accepts only Audio stream since he doesn't recognize
 bundle-only streams
end note
Alice<->Bob: Two-way Opus Audio

   +--------------------------------------+----------------------------+
   | SDP Contents                         | RFC#/Notes                 |
   +--------------------------------------+----------------------------+
   | v=0                                  | [RFC4566]                  |
   | o=- 20519 0 IN IP4 0.0.0.0           | [RFC4566]                  |
   | s=-                                  | [RFC4566]                  |
   | t=0 0                                | [RFC4566]                  |
   | a=msid-semantic:WMS                  | [MSID]                     |
   | a=group:BUNDLE m0 m1 m2              | [draft-ietf-mmusic-sdp-bun |
   |                                      | dle-negotiation] Alice     |
   |                                      | supports grouping of       |
   |                                      | m=lines under BUNDLE       |
   |                                      | semantics                  |
   | a=ice-options:trickle                | [draft-ivov-mmusic-trickle |
   |                                      | -ice]                      |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109  | [RFC4566]                  |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m0                             | [RFC5888] Audio m=line     |
   |                                      | part of BUNDLE group with  |
   |                                      | a unique port number       |
   | a=msid:ma ta                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (ta)                       |
   | a=rtpmap:109 opus/48000/2            | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=extmap:1 urn:ietf:params:rtp-      | [RFC6464]                  |
   | hdrext:ssrc-audio-level              |                            |
   | a=ptime:20                           | [draft-ietf-payload-rtp-op |
   |                                      | us]                        |
   | a=rtcp-fb:109 nack                   | [RFC5104]                  |



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   | a=sendrecv                           | [RFC3264]                  |
   | a=setup:actpass                      | [RFC4145] - Alice can      |
   |                                      | perform DTLS before Answer |
   |                                      | arrives                    |
   | a=rtcp-mux                           | [RFC5761]                  |
   | a=ice-ufrag:074c6550                 | [RFC5245]                  |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474a | [RFC5245]                  |
   | f08a068                              |                            |
   | a=fingerprint:sha-1 99:41:49:83:4a:9 | [RFC5245]                  |
   | 7:0e:1f:ef:6d:f7:c9:c7:70:9d:1f:66:7 |                            |
   | 9:a8:07                              |                            |
   | a=candidate:0 1 UDP  2113667327      | [RFC5245]                  |
   | 192.168.1.4 54609 typ host           |                            |
   | a=candidate:1 1 UDP  694302207       | [RFC5245]                  |
   | 24.23.204.141 54609 typ srflx raddr  |                            |
   | 192.168.1.4 rport 54609              |                            |
   | a=candidate:0 2 UDP 2113667326       | [RFC5245]                  |
   | 192.168.1.4 64678 typ host           |                            |
   | a=candidate:1 2 UDP  1694302206      | [RFC5245]                  |
   | 24.23.204.141 64678 typ srflx raddr  |                            |
   | 192.168.1.4 rport 64678              |                            |
   | a=ssrc:11111 cname:axzo1278npDlAzM73 | [RFC5576]E                 |
   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100   | bundle-only video line     |
   |                                      | with port number set to    |
   |                                      | zero                       |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m1                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=msid:ma tb                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tb)                       |
   | a=rtpmap:98 VP8/90000                | [draft-ietf-payload-vp8]   |
   | a=rtpmap:100 VP8/90000               | [draft-ietf-payload-vp8]   |
   | a=imageattr:98 [x=1280,y=720]        | [RFC6236]Camera-1,Encoding |
   |                                      | -1 Resolution              |
   | a=fmtp:98 max-fr=30                  | [RFC4566]                  |
   | a=imageattr:100 [x=640,y=480]        | [RFC6236]                  |
   |                                      | Camera-1,Encoding-2        |
   |                                      | Resolution                 |
   | a=fmtp:100 max-fr=15                 | [RFC4566]                  |
   | a=ssrc-group:SIMULCAST 12345 45678   | [RFC5576]                  |
   | a=ssrc:12345 cname:axzo1278npDlAzM73 | [RFC5576]E                 |
   | a=ssrc:45678 cname:axzo1278npDlAzM73 | [RFC5576]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |



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   | a=rtcp-rsize                         | [RFC5506]                  |
   | m=video 0 UDP/TLS/RTP/SAVPF 101 103  | bundle-only video line     |
   |                                      | with port number set to    |
   |                                      | zero                       |
   | c=IN IP4 24.23.204.141               | [RFC4566]                  |
   | a=rtcp:64678 IN IP4 24.23.204.141    | [RFC3605]                  |
   | a=mid:m2                             | [RFC5888] Video m=line     |
   |                                      | part of BUNDLE group       |
   | a=msid:ma tc                         | Identifies RTCMediaStream  |
   |                                      | ID (ma) and                |
   |                                      | RTCMediaStreamTrack ID     |
   |                                      | (tc)                       |
   | a=rtpmap:101 H264/90000              | [RFC3984]                  |
   | a=rtpmap:103 H264/90000              | [RFC3984]                  |
   | a=fmtp:101 profile-level-id=4d0028   | [RFC3984]Camera-2,Encoding |
   | ;packetization-mode=1;max-fr=30      | -1 Resolution              |
   | a=fmtp:100 profile-level-id=4d0028   | [RFC3984]Camera-1,Encoding |
   | ;packetization-mode=1;max-fr=15      | -2 Resolution              |
   | a=ssrc-group:SIMULCAST 67890 56789   | [RFC5576]                  |
   | a=ssrc:67890 cname:axzo1278npDlAzM73 | [RFC5576]                  |
   | a=ssrc:56789 cname:axzo1278npDlAzM73 | [RFC5576]                  |
   | a=bundle-only                        | [draft-roach-mmusic-unifie |
   |                                      | d-plan]                    |
   | a=rtcp-rsize                         | [RFC5506]                  |
   +--------------------------------------+----------------------------+

                 Table 40: 5.4.3 SDP Simulcast bundle-only

   +-------------------------------------------+-----------------------+
   | SDP Contents                              | RFC#/Notes            |
   +-------------------------------------------+-----------------------+
   | v=0                                       | [RFC4566]             |
   | o=- 20519 0 IN IP4 0.0.0.0                | [RFC4566]             |
   | s=-                                       | [RFC4566]             |
   | t=0 0                                     | [RFC4566]             |
   | a=msid-semantic:WMS                       | [MSID]                |
   | m=audio 49203 UDP/TLS/RTP/SAVPF 109       | [RFC4566]             |
   | c=IN IP4 24.23.204.141                    | [RFC4566]             |
   | a=rtcp:60065 IN IP4 24.23.204.141         | [RFC3605]             |
   | a=rtpmap:109 opus/48000/2                 | [draft-ietf-payload-r |
   |                                           | tp-opus]              |
   | a=extmap:1 urn:ietf:params:rtp-hdrext     | [RFC6464]             |
   | :ssrc-audio-level                         |                       |
   | a=ptime:20                                | [draft-ietf-payload-r |
   |                                           | tp-opus]              |
   | a=rtcp-fb:109 nack                        | [RFC5104]             |
   | a=sendrecv                                | [RFC3264]             |
   | a=setup:active                            | [RFC4145] - Bob       |



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   |                                           | carries out DTLS      |
   |                                           | Handshake in parallel |
   | a=ice-ufrag:ufrag:c300d85b                | [RFC5245]             |
   | a=ice-                                    | [RFC5245]             |
   | pwd:de4e99bd291c325921d5d47efbabd9a2      |                       |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e: | [RFC5245]             |
   | 1f:ef:6d:f7:c9:c7:70:9d:1f:66:79:a8:07    |                       |
   | a=candidate:0 1 UDP  2113667327           | [RFC5245]             |
   | 192.168.1.7 49203 typ host                |                       |
   | a=candidate:1 1 UDP  694302207            | [RFC5245]             |
   | 98.248.92.77 49203 typ srflx raddr        |                       |
   | 192.168.1.7 rport 49203                   |                       |
   | a=candidate:0 2 UDP 2113667326            | [RFC5245]             |
   | 192.168.1.7 60065 typ host                |                       |
   | a=candidate:1 2 UDP  1694302206           | [RFC5245]             |
   | 98.248.92.77 60065 typ srflx raddr        |                       |
   | 192.168.1.7 rport 60065                   |                       |
   | a=rtcp-rsize                              | [RFC5506]             |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100        | Bob doesn't recognize |
   |                                           | bundle-only and hence |
   |                                           | rejects the video     |
   |                                           | stream                |
   | c=IN IP4 98.248.92.77                     | [RFC4566]             |
   | a=rtpmap:98 VP8/90000                     | [draft-ietf-payload-v |
   |                                           | p8]                   |
   | a=rtpmap:100 VP8/90000                    | [draft-ietf-payload-v |
   |                                           | p8]                   |
   | a=imageattr:98 [x=1280,y=720]             | [RFC6236]Camera-1,Enc |
   |                                           | oding-1 Resolution    |
   | a=fmtp:98 max-fr=30                       | [RFC4566]             |
   | a=imageattr:100 [x=640,y=480]             | [RFC6236]             |
   |                                           | Camera-1,Encoding-2   |
   |                                           | Resolution            |
   | a=fmtp:100 max-fr=15                      | [RFC4566]             |
   | m=video 0 UDP/TLS/RTP/SAVPF 98 100        | Bob doesn't recognize |
   |                                           | bundle-only and hence |
   |                                           | rejects the video     |
   |                                           | stream                |
   | c=IN IP4 98.248.92.77                     | [RFC4566]             |
   | a=rtpmap:101 H264/90000                   | [RFC3984]             |
   | a=rtpmap:103 H264/90000                   | [RFC3984]             |
   | a=fmtp:101 profile-level-id=4d0028        | [RFC3984]Camera-2,Enc |
   | ;packetization-mode=1;max-fr=30           | oding-1 Resolution    |
   | a=fmtp:100 profile-level-id=4d0028        | [RFC3984]Camera-1,Enc |
   | ;packetization-mode=1;max-fr=15           | oding-2 Resolution    |
   +-------------------------------------------+-----------------------+

                         Table 41: 5.4.3 SDP Anwer



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5.4.4.  Legacy Interop with RTP/AVP profile

   In this section, we attempt to provide session descriptions
   showcasing inter-operability between a WebRTC end-point and a Legacy
   VOIP end-point.  The ideas included in here are not fully baked into
   the standards and might be controversial in nature.  The hope here is
   to demonstrate a plausible SDP composition to enchance seamless
   inter-operability between the aforementioned communication systems.

   In the scenario desribed below, Alice sends [RFC3264] Offer with two
   sets of media descriptions per media type.

      One set that correponds to [WebRTC] compliant UDP/TLS/RTP/SAVPF
      based audio and video descriptions.

      Another set with RTP/AVP based audio and video descriptions for
      the legacy Interop purposes.

      Also to note, Alice includes session level DTLS information and
      media level RTCP feedback information as applicable to both the
      sets of media descriptions

   On the other hand, Bob being a Legacy VOIP end-point, recognizes only
   the media descriptions with RTP/AVP as the application protocol.  The
   security and fedback requirements for the session are either handled
   by a intermediate gateway or with some combination of Bob's
   capabilities and the intermediate gateway.

   title Successful 2-Way WebRTC <-> VOIP Interop
   note right of Alice
   Alice is on a WebRTC end-point & Bob is behind a legacy VOIP system
   end note
   Alice->Bob: Offer(Audio:Opus Video:VP8)
   note right of Alice
    Alice includes 2 copies of media descriptions
    1. WebRTC compliant media description (UDP/TLS/RTP/SAVPF)
    2. Legacy compliant media description (RTP/AVP)
   end note
   Bob->Alice: Answer(Audio:Opus Video:VP8)
   note right of Bob
    Bob recognizes"legacy compliant" media description from Alice.
    and accepts the same.
   end note
   Alice->Bob: Two-way Opus Audio, VP8 Video
   note right of Alice
     Session also suports RTP/RTCP Mux, RTCP feedback (nack,pli)
   end note




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   +---------------------------------------------+---------------------+
   | SDP Contents                                | RFC#/Notes          |
   +---------------------------------------------+---------------------+
   | v=0                                         | [RFC4566]           |
   | o=- 20518 0 IN IP4 0.0.0.0                  | [RFC4566]           |
   | s=-                                         | [RFC4566]           |
   | t=0 0                                       | [RFC4566]           |
   | a=ice-ufrag:074c6550                        | [RFC5245]           |
   | a=ice-pwd:a28a397a4c3f31747d1ee3474af08a068 | [RFC5245]           |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e:1f | [RFC5245]           |
   | :ef:6d:f7:c9:c7:70:9d:1f:66:79:a8:07        |                     |
   | a=rtcp-rsize                                | [RFC5506]           |
   | m=audio 54609 UDP/TLS/RTP/SAVPF 109         | [RFC4566]           |
   | c=IN IP4 24.23.204.141                      | [RFC4566]           |
   | a=rtpmap:109 opus/48000                     |                     |
   | a=ptime:20                                  |                     |
   | a=sendrecv                                  | [RFC3264]           |
   | a=rtcp-mux                                  | [RFC5761]           |
   | a=candidate:0 1 UDP  2113667327 192.168.1.4 | [RFC5245]           |
   | 54609 typ host                              |                     |
   | a=candidate:1 1 UDP  694302207              | [RFC5245]           |
   | 24.23.204.141 54609 typ srflx raddr         |                     |
   | 192.168.1.4 rport 54609                     |                     |
   | a=candidate:0 2 UDP 2113667326 192.168.1.4  | [RFC5245]           |
   | 64678 typ host                              |                     |
   | a=candidate:1 2 UDP  1694302206             | [RFC5245]           |
   | 24.23.204.141 64678 typ srflx raddr         |                     |
   | 192.168.1.4 rport 64678                     |                     |
   | a=rtcp-fb:109 nack                          | [RFC5104]           |
   | m=video  62537 UDP/TLS/RTP/SAVPF 120        | [RFC4566]           |
   | c=IN IP4 24.23.204.141                      | [RFC4566]           |
   | a=rtpmap:120 VP8/90000                      | [draft-ietf-payload |
   |                                             | -vp8]               |
   | a=sendrecv                                  | [RFC3264]           |
   | a=rtcp-mux                                  | [RFC5761]           |
   | a=candidate:0 1 UDP  2113667327 192.168.1.4 | [RFC5245]           |
   | 62537 typ host                              |                     |
   | a=candidate:1 1 UDP  1694302207             | [RFC5245]           |
   | 24.23.204.141 62537 typ srflx raddr         |                     |
   | 192.168.1.4 rport 62537                     |                     |
   | a=candidate:0 2 2113667326 192.168.1.4      | [RFC5245]           |
   | 54721 typ host                              |                     |
   | a=candidate:1 2 UDP 1694302206              | [RFC5245]           |
   | 24.23.204.141 54721 typ srflx raddr         |                     |
   | 192.168.1.4 rport 54721                     |                     |
   | a=rtcp-fb:120 nack pli                      | [RFC5104]           |
   | a=rtcp-fb:120 ccm fir                       | [RFC5104]           |
   | ---------------                             | These set of media  |



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   |                                             | descriptions are    |
   |                                             | for Legacy Inter-op |
   |                                             | purposes            |
   | m=audio 54732 RTP/AVP 109                   | [RFC4566]Alice      |
   |                                             | includes RTP/AVP    |
   |                                             | audio stream        |
   |                                             | description         |
   | c=IN IP4 24.23.204.141                      | [RFC4566]           |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e:1f | [RFC5245]           |
   | :7f:7d:f9:c9:c7:70:9d:1f:66:79:a8:07        |                     |
   | a=rtpmap:109 opus/48000                     |                     |
   | a=ptime:20                                  |                     |
   | a=sendrecv                                  | [RFC3264]           |
   | a=rtcp-mux                                  | [RFC5761]Alice      |
   |                                             | still includes      |
   |                                             | RTP/RTCP Mux        |
   |                                             | support             |
   | a=candidate:0 1 UDP  2113667327 192.168.1.4 | [RFC5245]           |
   | 54732 typ host                              |                     |
   | a=candidate:1 1 UDP  694302207              | [RFC5245]           |
   | 24.23.204.141 54732 typ srflx raddr         |                     |
   | 192.168.1.4 rport 54732                     |                     |
   | a=candidate:0 2 UDP 2113667326 192.168.1.4  | [RFC5245]           |
   | 64678 typ host                              |                     |
   | a=candidate:1 2 UDP  1694302206             | [RFC5245]           |
   | 24.23.204.141 64678 typ srflx raddr         |                     |
   | 192.168.1.4 rport 64678                     |                     |
   | a=rtcp-fb:109 nack                          | [RFC5104]She adds   |
   |                                             | her intent for NACK |
   |                                             | RTCP feedback       |
   |                                             | support             |
   | m=video  62445 RTP/AVP 120                  | [RFC4566]Alice      |
   |                                             | includes RTP/AVP    |
   |                                             | video stream        |
   |                                             | description         |
   | c=IN IP4 24.23.204.141                      | [RFC4566]           |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e:1f | [RFC5245]           |
   | :ef:7d:f7:c9:c7:70:9d:1f:66:79:a8:07        |                     |
   | a=rtpmap:120 VP8/90000                      | [draft-ietf-payload |
   |                                             | -vp8]               |
   | a=sendrecv                                  | [RFC3264]           |
   | a=rtcp-mux                                  | [RFC5761]Alice      |
   |                                             | intends to perform  |
   |                                             | RTP/RTCP Mux        |
   | a=candidate:0 1 UDP  2113667327 192.168.1.4 | [RFC5245]           |
   | 62445 typ host                              |                     |
   | a=candidate:1 1 UDP  1694302207             | [RFC5245]           |
   | 24.23.204.141 62537 typ srflx raddr         |                     |



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   | 192.168.1.4 rport 62445                     |                     |
   | a=candidate:0 2 2113667326 192.168.1.4      | [RFC5245]           |
   | 54721 typ host                              |                     |
   | a=candidate:1 2 UDP 1694302206              | [RFC5245]           |
   | 24.23.204.141 54721 typ srflx raddr         |                     |
   | 192.168.1.4 rport 54721                     |                     |
   | a=rtcp-fb:120 nack pli                      | [RFC5104] Alice     |
   |                                             | indicates support   |
   |                                             | for Picture loss    |
   |                                             | Indication and NACK |
   |                                             | RTCP feedback       |
   | a=rtcp-fb:120 ccm fir                       | [RFC5104]           |
   +---------------------------------------------+---------------------+

                         Table 42: 5.4.5 SDP Offer




































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   +---------------------------------------------+---------------------+
   | SDP Contents                                | RFC#/Notes          |
   +---------------------------------------------+---------------------+
   | v=0                                         | [RFC4566]           |
   | o=-  16833 0 IN IP4 0.0.0.0                 | [RFC4566]           |
   | s=-                                         | [RFC4566]           |
   | t=0 0                                       | [RFC4566]           |
   | a=ice-ufrag:c300d85b                        | [RFC5245]           |
   | a=ice-pwd:de4e99bd291c325921d5d47efbabd9a2  | [RFC5245]           |
   | a=fingerprint:sha-1 99:41:49:83:4a:97:0e:1f | [RFC5245]           |
   | :ef:6d:f7:c9:c7:70:9d:1f:66:79:a8:07        |                     |
   | m=audio 49203 RTP/AVP 109                   | [RFC4566] Bob       |
   |                                             | accepts RTP/AVP     |
   |                                             | based audio stream  |
   | c=IN IP4 98.248.92.77                       | [RFC4566]           |
   | a=rtpmap:109 opus/48000                     |                     |
   | a=ptime:20                                  |                     |
   | a=sendrecv                                  | [RFC3264]           |
   | a=candidate:0 1 UDP 2113667327 192.168.1.7  | [RFC5245]           |
   | 49203 typ host                              |                     |
   | a=candidate:1 1 UDP 1694302207 98.248.92.77 | [RFC5245]           |
   | 49203 typ srflx raddr 192.168.1.7 rport     |                     |
   | 49203                                       |                     |
   | a=candidate:0 2 UDP 2113667326 192.168.1.7  | [RFC5245]           |
   | 60065 typ host                              |                     |
   | a=candidate:1 2 UDP 1694302206 98.248.92.77 | [RFC5245]           |
   | 60065 typ srflx raddr 192.168.1.7 rport     |                     |
   | 60065                                       |                     |
   | m=video  63130 RTP/SAVP 120                 | [RFC4566] Bob       |
   |                                             | accepts RTP/AVP     |
   |                                             | based video stram   |
   | c=IN IP4 98.248.92.771                      | [RFC4566]           |
   | a=rtpmap:120 VP8/90000                      | [draft-ietf-payload |
   |                                             | -vp8]               |
   | a=sendrecv                                  | [RFC3264]           |
   | a=candidate:0 1 UDP 2113667327 192.168.1.7  | [RFC5245]           |
   | 63130 typ host                              |                     |
   | a=candidate:1 1 UDP 1694302207 98.248.92.77 | [RFC5245]           |
   | 63130 typ srflx raddr 192.168.1.7 rport     |                     |
   | 63130                                       |                     |
   | a=candidate:0 2 UDP 2113667326 192.168.1.7  | [RFC5245]           |
   | 56607 typ host                              |                     |
   | a=candidate:1 2 UDP 1694302206 98.248.92.77 | [RFC5245]           |
   | 56607 typ srflx raddr 192.168.1.7 rport     |                     |
   | 56607                                       |                     |
   +---------------------------------------------+---------------------+

                        Table 43: 5.4.5 SDP Answer



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6.  IANA Considerations

   This document requires no actions from IANA.

7.  Acknowledgments

   We would like to thanks Justin Uberti, Chris Flo for his detailed
   review and inputs.

8.  Change Log

   [RFC EDITOR NOTE: Please remove this section when publishing]

   Changes from draft-nandakumar-rtcweb-sdp-04

   o  Interim version of the draft to avert expiry

   o  Corrected placement of c= line as per RFC4566

   o  Updated simulcast SDP to reflect draft-westerlund-avtcore-rtp-
      simulcast-04

   Changes from draft-nandakumar-rtcweb-sdp-03

   o  Aligned more closely with JSEP version -05

   o  Added Conventions to help readability

   o  Add more examples to clarify BUNDLE use-cases

   Changes from draft-nandakumar-rtcweb-sdp-02

   o  Major refactoring was done to group the examples in to categories

   o  SDP was updated through out to reflect JSEP-04 style of defining
      attributes per m=line than at the session level.

   o  Added 8 new examples.

   o  Updated references for Trickle, Unified Plan

   o  Add section to explain the syntax conventions followed in the
      examples.

   Changes from draft-nandakumar-rtcweb-sdp-01

   o  Updated references to OPUS RTP Payload Specification.




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   o  Updated BUNDLE examples based on the latest draft-ietf-mmusic-sdp-
      bundle-negotiation.

   o  Added examples for multiple audio and video flows based on Unified
      Plan.

   o  Added new examples for RTX and FEC streams

   o  Updated Simulcast and SVC examples

   Changes from draft-nandakumar-rtcweb-sdp-00

   o  Fixed editorial comments on the mailing list.

   o  Updated Data-channel SDP information based on draft-ietf-mmusic-
      sctp-sdp.

   o  Updated BUNDLE examples based on draft-ietf-mmusic-sdp-bundle-
      negotiation.

   o  Added examples for few more BUNDLE variants

   o  Added new examples for Simulcast and SVC

9.  References

9.1.  Normative References

   [RFC3264]  Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
              with Session Description Protocol (SDP)", RFC 3264, June
              2002.

   [RFC4566]  Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
              Description Protocol", RFC 4566, July 2006.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

9.2.  Informative References

   [RFC5245]  Rosenberg, J., "Interactive Connectivity Establishment
              (ICE): A Protocol for Network Address Translator (NAT)
              Traversal for Offer/Answer Protocols", RFC 5245, July
              2006.

   [WebRTC]   W3C, "WebRTC 1.0: Real-time Communication Between
              Browsers",
              <http://dev.w3.org/2011/webrtc/editor/webrtc.html> , .



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   [JSEP]     Uberti, J. and C. Jennigs, "Javascript Session
              Establishment Protocol", draft-ietf-rtcweb-jsep (work in
              progress), December 2012.

   [MSID]     Alvestrand, H., "Cross Session Stream Identification in
              the Session Description Protocol", draft-ietf-mmusic-msid
              (work in progress), January 2014.

   [RFC5506]  Johansson, I., "Support for Reduced-Size Real-Time
              Transport Control Protocol (RTCP): Opportunities and
              Consequences", RFC 5506, April 2009.

   [RFC3551]  Schulzrinne, H. and S. Casner, "RTP Profile for Audio and
              Video Conferences with Minimal Control", RFC 3551, July
              2003.

   [RFC3952]  Duric, A. and S. Andersen, "Real-time Transport Protocol
              (RTP) Payload Format for internet Low Bit Rate Codec
              (iLBC) Speech", RFC 3952, December 2004.

   [RFC4796]  Hautakorpi, J. and G. Camarillo, "The Session Description
              Protocol (SDP) Content Attribute", RFC 4796, February
              2007.

   [RFC5761]  Perkins, C. and M. Westerlund, "Multiplexing RTP Data and
              Control Packets on a Single Port", RFC 5761, April 2010.

   [RFC3556]  Casner, S., "Session Description Protocol (SDP) Bandwidth
              Modifiers for RTP Control Protocol (RTCP) Bandwidth", RFC
              3556, July 2003.

   [RFC5104]  Wenger, S., Chandra, U., Westerlund, M., and B. Burman,
              "Codec Control Messages in the RTP Audio-Visual Profile
              with Feedback (AVPF)", RFC 5104, February 2008.

   [RFC4588]  Rey, J., Leon, D., Miyazaki, A., Varsa, V., and R.
              Hakenberg, "RTP Retransmission Payload Format", RFC 4588,
              July 2006.

   [RFC5956]  Begen, A., "Forward Error Correction Grouping Semantics in
              the Session Description Protocol", RFC 5956, September
              2010.

   [RFC5888]  Camarillo, G. and H. Schulzrinne, "RTP Payload Format for
              H.264 Video", RFC 5888, June 2010.






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   [RFC6236]  Johansson, I. and K. Jung, "Negotiation of Generic Image
              Attributes in the Session Description Protocol (SDP)", RFC
              6236, May 2011.

   [draft-ietf-payload-rtp-opus]
              Spittka, J., Vos, K., and JM. Valin, "RTP Payload Format
              for Opus Speech and Audio Codec", draft-ietf-payload-rtp-
              opus-00 (work in progress), July 2012.

   [draft-ietf-payload-vp8]
              Westin, P., Lundin, H., Glover, M., Uberti, J., and F.
              Galligan, "RTP Payload Format for VP8 Video", draft-ietf-
              payload-vp8-05 (work in progress), August 2012.

   [RFC3984]  Wenger, S., Hannuksela, M., Stockhammer, T., Westerlund,
              M., and D. Singer, "RTP Payload Format for H.264 Video",
              RFC 3984, February 2005.

   [RFC5583]  Schierl, T. and S. Wenger, "Signaling Media Decoding
              Dependency in the Session Description Protocol (SDP)", RFC
              5583, July 2009.

   [RFC5576]  Lennox, J., Ott, J., and T. Schierl, "Source-Specific
              Media Attributes in the Session Description Protocol
              (SDP)", RFC 5576, June 2009.

   [draft-ietf-rtcweb-data-channel]
              Jesup, R., Loreto, S., and M. Tuexen, "RTCWeb Datagram
              Connection", draft-ietf-rtcweb-data-channel-01 (work in
              progress), September 2012.

   [draft-ietf-mmusic-sctp-sdp]
              Loreto, S. and G. Camarillo, "Stream Control Transmission
              Protocol (SCTP)-Based Media Transport in the Session
              Description Protocol (SDP)", draft-ietf-mmusic-sctp-sdp-03
              (work in progress), September 2012.

   [draft-ietf-mmusic-sdp-bundle-negotiation]
              Holmberg, C., Alvestrand, H., and C. Jennings,
              "Multiplexing Negotiation Using Session Description
              Protocol (SDP) Port Numbers", draft-ietf-mmusic-sdp-
              bundle-negotiation-04 (work in progress), February 2013.

   [draft-roach-mmusic-unified-plan]
              Roach, A., Uberti, J., and M. Thomson, "A Unified Plan for
              Using SDP with Large Numbers of Media Flows", draft-roach-
              mmusic-unified-plan (work in progress), July 2013.




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   [draft-westerlund-avtcore-rtp-simulcast]
              Westerlund, M., Burman, B., and S. Nandakumar, "Using
              Simulcast in RTP Sessions.", draft-westerlund-avtcore-rtp-
              simulcast (work in progress), July 2014.

   [draft-ivov-mmusic-trickle-ice]
              Roach, A., Uberti, J., and M. Thomson, "A Unified Plan for
              Using SDP with Large Numbers of Media Flows", draft-ivov-
              mmusic-trickle-ice-01 (work in progress), July 2013.

   [draft-lennox-mmusic-sdp-source-selection]
              Lennox, J. and H. Schulzrinne, "Multiplexing Negotiation
              Using Session Description Protocol (SDP) Port Numbers",
              draft-lennox-mmusic-sdp-source-selection-05 (work in
              progress), October 2012.

   [draft-rescorla-avtcore-6222bis]
              Rescorla, E. and A. Begen, "Guidelines for Choosing RTP
              Control Protocol (RTCP) Canonical Names (CNAMEs)", draft-
              rescorla-avtcore-6222bis-00 (work in progress), October
              2012.

   [RFC3550]  Schulzrinne, H., Schulzrinne, S., Frederick, R., and V.
              Jacobson, "RTP: A Transport Protocol for Real-Time
              Applications", RFC 2326, July 2003.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              June 2002.

   [RFC2326]  Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time
              Streaming Protocol (RTSP)", RFC 2326, April 1998.

   [RFC3605]  Huitema, C., "Real Time Control Protocol (RTCP) attribute
              in Session Description Protocol (SDP)", RFC 4145, October
              2003.

   [RFC4145]  Fischl, J., Tschofenig, H., and E. Rescorla, "Framework
              for Establishing a Secure Real-time Transport Protocol
              (SRTP) Security Context Using Datagram Transport Layer
              Security (DTLS)", RFC 4145, May 2010.

   [RFC2833]  Schulzrinne, H. and S. Petrack, "RTP Payload for DTMF
              Digits, Telephony Tones and Telephony Signals", RFC 2833,
              May 2000.





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   [RFC6464]  Lennox, J., Ivov, E., and E. Marocco, "A Real-time
              Transport Protocol (RTP) Header Extension for Client-to-
              Mixer Audio Level Indication", RFC 6464, December 2011.

   [RFC6465]  Ivov, E., Marocco, E., and J. Lennox, "A Real-time
              Transport Protocol (RTP) Header Extension for Mixer-to-
              Client Audio Level Indication", RFC 6465, December 2011.

Authors' Addresses

   Suhas Nandakumar
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   Email: snandaku@cisco.com


   Cullen Jennings
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   Phone: +1 408 421-9990
   Email: fluffy@cisco.com
























Nandakumar & Jennings   Expires February 13, 2015             [Page 104]