Session Description Protocol (SDP) Offer/Answer Procedures for Interactive Connectivity Establishment (ICE)
RFC 8839

Document Type RFC - Proposed Standard (January 2021; No errata)
Obsoletes RFC 5245, RFC 6336
Authors Marc Petit-Huguenin  , Suhas Nandakumar  , Christer Holmberg  , Ari Keränen  , Roman Shpount
Last updated 2021-01-18
Replaces draft-petithuguenin-mmusic-ice-sip-sdp
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Stream WG state Submitted to IESG for Publication
Document shepherd Flemming Andreasen
Shepherd write-up Show (last changed 2019-06-06)
IESG IESG state RFC 8839 (Proposed Standard)
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(None)
Consensus Boilerplate Yes
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Responsible AD Adam Roach
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IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack


Internet Engineering Task Force (IETF)                 M. Petit-Huguenin
Request for Comments: 8839                            Impedance Mismatch
Obsoletes: 5245, 6336                                      S. Nandakumar
Category: Standards Track                                  Cisco Systems
ISSN: 2070-1721                                              C. Holmberg
                                                              A. Keränen
                                                                Ericsson
                                                              R. Shpount
                                                             TurboBridge
                                                            January 2021

     Session Description Protocol (SDP) Offer/Answer Procedures for
              Interactive Connectivity Establishment (ICE)

Abstract

   This document describes Session Description Protocol (SDP) Offer/
   Answer procedures for carrying out Interactive Connectivity
   Establishment (ICE) between the agents.

   This document obsoletes RFCs 5245 and 6336.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8839.

Copyright Notice

   Copyright (c) 2021 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
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   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
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   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
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   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1.  Introduction
   2.  Conventions
   3.  Terminology
   4.  SDP Offer/Answer Procedures
     4.1.  Introduction
     4.2.  Generic Procedures
       4.2.1.  Encoding
       4.2.2.  RTP/RTCP Considerations
       4.2.3.  Determining Role
       4.2.4.  STUN Considerations
       4.2.5.  Verifying ICE Support Procedures
       4.2.6.  SDP Example
     4.3.  Initial Offer/Answer Exchange
       4.3.1.  Sending the Initial Offer
       4.3.2.  Sending the Initial Answer
       4.3.3.  Receiving the Initial Answer
       4.3.4.  Concluding ICE
     4.4.  Subsequent Offer/Answer Exchanges
       4.4.1.  Sending Subsequent Offer
       4.4.2.  Sending Subsequent Answer
       4.4.3.  Receiving Answer for a Subsequent Offer
   5.  Grammar
     5.1.  "candidate" Attribute
     5.2.  "remote-candidates" Attribute
     5.3.  "ice-lite" and "ice-mismatch" Attributes
     5.4.  "ice-ufrag" and "ice-pwd" Attributes
     5.5.  "ice-pacing" Attribute
     5.6.  "ice-options" Attribute
   6.  Keepalives
   7.  SIP Considerations
     7.1.  Latency Guidelines
       7.1.1.  Offer in INVITE
       7.1.2.  Offer in Response
     7.2.  SIP Option Tags and Media Feature Tags
     7.3.  Interactions with Forking
     7.4.  Interactions with Preconditions
     7.5.  Interactions with Third Party Call Control
   8.  Interactions with Application Layer Gateways and SIP
   9.  Security Considerations
     9.1.  IP Address Privacy
     9.2.  Attacks on the Offer/Answer Exchanges
     9.3.  The Voice Hammer Attack
   10. IANA Considerations
     10.1.  SDP Attributes
       10.1.1.  "candidate" Attribute
       10.1.2.  "remote-candidates" Attribute
       10.1.3.  "ice-lite" Attribute
       10.1.4.  "ice-mismatch" Attribute
       10.1.5.  "ice-pwd" Attribute
       10.1.6.  "ice-ufrag" Attribute
       10.1.7.  "ice-options" Attribute
       10.1.8.  "ice-pacing" Attribute
     10.2.  Interactive Connectivity Establishment (ICE) Options
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