The IESG has approved the following document: - 'Differentiated Services (DiffServ) and Real-time Communication' (draft-ietf-dart-dscp-rtp-10.txt) as Informational RFC This document is the product of the DiffServ Applied to Real-time Transports Working Group. The IESG contact persons are Richard Barnes and Alissa Cooper. A URL of this Internet Draft is: http://datatracker.ietf.org/doc/draft-ietf-dart-dscp-rtp/ Technical Summary This document describes the interaction between Differentiated Services (DiffServ) network quality of service (QoS) functionality and real-time network communication, including communication based on the Real-time Transport Protocol (RTP). DiffServ is based on network nodes applying different forwarding treatments to packets whose IP headers are marked with different DiffServ Code Points (DSCPs). WebRTC applications, as well as some conferencing applications, have begun using the Session Description Protocol (SDP) bundle negotiation mechanism to send multiple traffic streams with different QoS requirements using the same network 5-tuple. Use of different DSCPs to obtain different QoS treatments within a single network 5-tuple, the results (e.g., reordering) may cause transport protocol interactions, particularly with congestion control functionality. In addition, DSCP markings may be changed or removed between the traffic source and destination. This document covers the implications of these DiffServ aspects for real-time network communication, including WebRTC. Working Group Summary The DART working group was formed in April of 2014. The working group was chartered to focus on a constrained problem and conclude quickly. DART adopted this document with very little controversy. While the working group is nominally in the RAI area, it has been effectively a cross-area effort between RAI and TSV. This document resulted in lively discussion among a core group of experts from both areas. In general, the discussion converged quickly, and there were no unresolved controversies. In the shepherd's opinion, the only impediment to consensus was that discussion kept overturning rocks, forcing participants to think about new issues. One notable issue was whether this draft should offer guidance on the interaction between having multiple DSCPs in a stream and the multiple stream optimization work (draft-ietf-avtcore-rtp-multi-stream-optimisation.) The working group chose to avoid such guidance in this draft, and leave that for the multi-stream draft to solve. Document Quality During the working group last call, we solicited comments from RTCWEB, AVTCORE, MMUSIC, CLUE, TSVWG, and RMCAT. In the shepherd's opinion, it has been well reviewed, and represents a strong consensus. The shepherd does not think it needs any further specific reviews, other than the usual reviews it would receive during the IETF last call process (for example, Gen-ART and SecDir). Since the document does not specify protocol, it will not be directly implemented. However, we expect that at least the RTCWEB working group will incorporate guidance from this document into it's output. Personnel The Document Shepherd is Ben Campbell. The Responsible AD is Richard Barnes.
