RFC 3714 (rfc3714) - Page 1 of 32
IAB Concerns Regarding Congestion Control for Voice Traffic in the Internet
Alternative Format: Original Text Document
Network Working Group S. Floyd, Ed.
Request for Comments: 3714 J. Kempf, Ed.
Category: Informational March 2004
IAB Concerns Regarding Congestion Control for
Voice Traffic in the Internet
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This document discusses IAB concerns about effective end-to-end
congestion control for best-effort voice traffic in the Internet.
These concerns have to do with fairness, user quality, and with the
dangers of congestion collapse. The concerns are particularly
relevant in light of the absence of a widespread Quality of Service
(QoS) deployment in the Internet, and the likelihood that this
situation will not change much in the near term. This document is
not making any recommendations about deployment paths for Voice over
Internet Protocol (VoIP) in terms of QoS support, and is not claiming
that best-effort service can be relied upon to give acceptable
performance for VoIP. We are merely observing that voice traffic is
occasionally deployed as best-effort traffic over some links in the
Internet, that we expect this occasional deployment to continue, and
that we have concerns about the lack of effective end-to-end
congestion control for this best-effort voice traffic.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. An Example of the Potential for Trouble. . . . . . . . . . . . 4
3. Why are Persistent, High Drop Rates a Problem? . . . . . . . . 6
3.1. Congestion Collapse. . . . . . . . . . . . . . . . . . . 6
3.2. User Quality . . . . . . . . . . . . . . . . . . . . . . 7
3.3. The Amorphous Problem of Fairness. . . . . . . . . . . . 8
4. Current efforts in the IETF. . . . . . . . . . . . . . . . . . 10
4.1. RTP. . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2. TFRC . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3. DCCP . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Floyd & Kempf Informational