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)
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.
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[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].
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.
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.