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Internet Engineering Task Force (IETF) T. Terriberry
Request for Comments: 7007 Mozilla Corporation
Updates: 3551 August 2013
Category: Standards Track
ISSN: 2070-1721


Update to Remove DVI4 from the Recommended Codecs for the RTP Profile
for Audio and Video Conferences with Minimal Control (RTP/AVP)

Abstract

The RTP Profile for Audio and Video Conferences with Minimal Control
(RTP/AVP) is the basis for many other profiles, such as the Secure
Real-time Transport Protocol (RTP/SAVP), the Extended RTP Profile for
Real-time Transport Control Protocol (RTCP)-Based Feedback
(RTP/AVPF), and the Extended Secure RTP Profile for RTCP-Based
Feedback (RTP/SAVPF). This document updates RFC 3551, the RTP/AVP
profile (and by extension, the profiles that build upon it), to
reflect changes in audio codec usage since that document was
originally published.

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 5741.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7007.
















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Copyright Notice

Copyright (c) 2013 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 ....................................................2
2. Terminology .....................................................2
3. Updates to RFC 3551 .............................................3
3.1. Updates to Section 6 of RFC 3551 ...........................3
4. Security Considerations .........................................3
5. Acknowledgments .................................................3
6. References ......................................................4
6.1. Normative References .......................................4
6.2. Informative References .....................................4

1. Introduction

[RFC3551] says that audio applications operating under the RTP/AVP
profile SHOULD be able to send and receive PCMU and DVI4. However,
in practice, many RTP deployments do not support DVI4, and there is
little reason to use it when much more modern codecs are available.
This document updates the recommended audio codec selection for the
RTP/AVP profile and removes the SHOULD for DVI4. By extension, this
also updates the profiles that build on RTP/AVP, including RTP/SAVP
[RFC3711], RTP/AVPF [RFC4585], and RTP/SAVPF [RFC5124].

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 [RFC2119].








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3. Updates to RFC 3551

The following text of [RFC3551] is hereby updated as set forth in
Section 3.1:

Audio applications operating under this profile SHOULD, at a
minimum, be able to send and/or receive payload types 0 (PCMU)
and 5 (DVI4). This allows interoperability without format
negotiation and ensures successful negotiation with a conference
control protocol.

3.1. Updates to Section 6 of RFC 3551

This document updates the final paragraph of Section 6 of RFC 3551 by
replacing "payload types 0 (PCMU) and 5 (DVI4)" with "payload
type 0 (PCMU)". We also add a final sentence to that paragraph that
states, "Some environments necessitate support for PCMU". This
results in the following paragraph:

Audio applications operating under this profile SHOULD, at a
minimum, be able to send and/or receive payload type 0 (PCMU).
This allows interoperability without format negotiation and
ensures successful negotiation with a conference control protocol.
Some environments necessitate support for PCMU.

4. Security Considerations

This document does not introduce any new security considerations for
[RFC3551].

5. Acknowledgments

Thanks to Colin Perkins for suggesting this update.


















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6. References

6.1. Normative References

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

[RFC3551] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and
Video Conferences with Minimal Control", STD 65, RFC 3551,
July 2003.

6.2. Informative References

[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)",
RFC 3711, March 2004.

[RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey,
"Extended RTP Profile for Real-time Transport Control
Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, July
2006.

[RFC5124] Ott, J. and E. Carrara, "Extended Secure RTP Profile for
Real-time Transport Control Protocol (RTCP)-Based Feedback
(RTP/SAVPF)", RFC 5124, February 2008.

Author's Address

Timothy B. Terriberry
Mozilla Corporation
650 Castro Street
Mountain View, CA 94041
USA

Phone: +1 650 903-0800
EMail: tterribe@xiph.org















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