Technical Summary
The RTP Control Protocol (RTCP) Canonical Name (CNAME) is a
persistent transport-level identifier for an RTP endpoint. While the
Synchronization Source (SSRC) identifier of an RTP endpoint may
change if a collision is detected or when the RTP application is
restarted, its RTCP CNAME is meant to stay unchanged, so that RTP
endpoints can be uniquely identified and associated with their RTP
media streams.
For proper functionality, RTCP CNAMEs should be unique within the
participants of an RTP session. However, the existing guidelines for
choosing the RTCP CNAME provided in the RTP standard are insufficient
to achieve this uniqueness. RFC 6222 was published to update those
guidelines to allow endpoints to choose unique RTCP CNAMEs.
Unfortunately, later investigations showed that some parts of the new
algorithms were unnecessarily complicated and/or ineffective. This
document addresses these concerns and replaces RFC 6222.
Working Group Summary
The requirements for this replacement of RFC 6222 came from RTCWEB WG, which identified the linkability and privacy issue of the previous random method. There was strong WG consensus to address this issue. The method of addressing it, using a cryptographic random number generator, was obvious. The main concern in WG last call has been around the clarity of the motivation for the update.
Document Quality
The Shepherd assumes that this will see significant implementation, especially initially in any WebRTC implementations. The document has gotten a fair amount of reviews in the WG last call.
Personnel
Magnus Westerlund is the Document Shepherd.
Richard Barnes is the Responsible Area Director.