Network Working Group C. Jennings
Internet-Draft Cisco
Intended status: Informational J. Uberti
Expires: August 17, 2013 Google
E. Rescorla
Mozilla
February 13, 2013
Requirements from various WG for MMUSIC
draft-jennings-mmusic-media-req-00
Abstract
This document outlines some of the requirements driving various
consideration related to multiplexing in the MMUSIC working group to
meet the needs of WebRTC, CLUE, and other working groups.
This document is only meant to be used to help drive the discussion
of solutions and is not intended to become an RFC.
Status of this Memo
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provisions of BCP 78 and BCP 79. This document may not be modified,
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This Internet-Draft will expire on August 17, 2013.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Non-Requirements . . . . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4
8.1. Normative References . . . . . . . . . . . . . . . . . . . 4
8.2. Informative References . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5
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1. Introduction
For the past several meetings, there has been discussions around
various mechanism to reduce the number of UDP ports needed by
applications for RTP. This document attempts to capture some of the
requirements that are important in selecting the solution for how to
represent the SDP to negotiate the RTP media that is using reduced
ports.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
This document generically uses RTP to mean RTP and SRTP.
3. Requirements
This section covers the requirements from various WG for setting up
media. Obviously it does not try and cover all the requirements but
it tries to cover a set that seem relevant to decisions around
multiplexing onto few UDP ports.
High Priority Requirements:
1. Support many media flows but minimize the number of transport
flows. For instance, all media flows--or perhaps all media flows
of a given type--might be multiplexed over a single transport
flow.
2. Be able to successfully negotiate media with both legacy SIP
devices and new devices (whether SIP or RTCWEB) with a single
offer/answer exchange. If both endpoints support multiplexed
media, then multiplexing should be negotiated. Otherwise, non-
multiplexed media should be used. In many cases, each endpoints
will have no prior knowledge of capabilities of the other
endpoint.
Other Requirements:
1. Need a uniform way to allow specifications of new SDP parameters
to easily explain any implications that multiplexing has on the
new parameters in that specification.
2. Allow different sources (E.g. cameras) to use different codecs.
For example, if one camera had hardware encoders for VP8 while
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another had encoders for H.264, the device may wish to negotiate
different codecs.
3. Be able to to independently set parameters such as resolution
bandwidth, independently for each RTCWeb Track, preferably even
when they are all multiplexed over the same transport flow.
4. Be able to identify the RTCWeb tracks with an identifier that is
stable over the duration of the session. More information can be
found in [I-D.alvestrand-mmusic-msid].
4. Non-Requirements
Some items are not a major goal. If methods are found that work for
these as well, that is great, but they are not a priority item.
1. Working with SIP proxies or B2BUA that are not compliant with the
standards. The reason for this is it is just not possible to
design for every possible thing that does not do what the
standards require.
5. IANA Considerations
This document makes no request of IANA.
6. Security Considerations
These requirements have no additional security considerations other
than those captured in [I-D.ietf-rtcweb-security-arch].
7. Acknowledgements
Thanks to ...
8. References
8.1. Normative References
[I-D.ietf-rtcweb-security-arch]
Rescorla, E., "RTCWEB Security Architecture",
draft-ietf-rtcweb-security-arch-06 (work in progress),
October 2012.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[I-D.alvestrand-mmusic-msid]
Alvestrand, H., "Cross Session Stream Identification in
the Session Description Protocol",
draft-alvestrand-mmusic-msid-02 (work in progress),
December 2012.
Authors' Addresses
Cullen Jennings
Cisco
400 3rd Avenue SW, Suite 350
Calgary, AB T2P 4H2
Canada
Email: fluffy@iii.ca
Justin Uberti
Google
747 6th Ave S
Kirkland, WA 98033
USA
Email: justin@uberti.name
Eric Rescorla
Mozilla
Phone: +1 650 678 2350
Email: ekr@rtfm.com
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