Protocol Action: Congestion Control Principles to BCP

[The IESG <[e-mail]>]

The IESG has approved the Internet-Draft 'Congestion Control
Principles' <draft-floyd-cong-04.txt> as a BCP. This has been reviewed
in the IETF but is not the product of an IETF Working Group.

The IESG contact persons are Scott Bradner and Allison Mankin.

Technical Summary
 
 The goal of this document is to explain why there is a need for congestion
 control in the Internet, and to discuss what constitutes correct congestion
 control.  One specific goal is to illustrate the dangers of neglecting to
 apply proper congestion control.  A second goal is to discuss the role of
 the IETF in standardizing new congestion control protocols.

 IETF standards concerning end-to-end congestion control focus either on
 specific protocols (e.g., TCP, reliable multicast protocols) or on the
 syntax and semantics of communications between the end nodes and routers
 about congestion information (e.g., Explicit Congestion Notification) or
 desired quality-of-service (diff-serv)).  The role of end-to-end congestion
 control is also discussed in an Informational RFC on "Recommendations on
 Queue Management and Congestion Avoidance in the Internet".  RFC 2309
 recommends the deployment of active queue management mechanisms in routers,
 and the continuation of design efforts towards mechanisms in routers to deal
 with flows that are unresponsive to congestion notification.  We freely
 borrow from RFC 2309 some of their general discussion of end-to-end
 congestion control.

 In contrast to the documents discussed above, this document is a more
 general discussion of the principles of congestion control.  One of the keys
 to the success of the Internet has been the congestion avoidance mechanisms
 of TCP. While TCP is still the dominant transport protocol in the Internet, it
 is not ubiquitous, and there are an increasing number of applications that, for
 one reason or another, choose not to use TCP.  Such traffic includes not
 only  multicast traffic, but unicast traffic such as streaming multimedia
 that does not require reliability; and traffic such as DNS or routing
 messages that consist of short transfers deemed critical to the operation of
 the network.  Much of this traffic does not use any form of either bandwidth
 reservations or end-to-end congestion control. The continued use of
 end-to-end congestion control by best-effort traffic is critical for
 maintaining the stability of the Internet.

 This document also discusses the general role of the IETF in the
 standardization of new congestion control protocols.

Working Group Summary

 This document was not the product of an IETF working group.  No issues were
 raised during IETF last  call.

Protocol Quality

 This document has been reviewed for the IESG by Scott Bradner and Vern
 Paxson.