Technical Summary
Real-time media streams that use RTP are, to some degree, resilient
against packet losses. Receivers may use the base mechanisms of
RTCP to report packet reception statistics and thus allow a sender
to adapt its transmission behavior in the mid-term as sole means
for feedback and feedback-based error repair (besides a few codec-
specific mechanisms). This document defines an extension to the
Audio-visual Profile (AVP) that enables receivers to provide,
statistically, more immediate feedback to the senders and thus
allow for short-term adaptation and efficient feedback-based repair
mechanisms to be implemented. This early feedback profile (AVPF)
maintains the AVP bandwidth constraints for RTCP and preserves
scalability to large groups.
This profile establishes specific repair uses for applications, and a
few general uses based on NACK. It is not intended to enable RTCP to
provide congestion control feedback.
Working Group Summary
The working group supported this document.
Protocol Quality
The accompanying Informational document supports the claims that
statistically the RTCP scaling of this feedback is compatible with that
of RFC 3550. There are also prototype implementations. Working group
review of the document especially covered the scalability and security
compatibility issues. Allison Mankin reviewed the documents for the
IESG.