rfc2914英文－拥塞控制.doc

Congestion Control Principles

Abstract
The goal of this document is to explain the need for congestion control in the , 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.
Key Words: congestion control,RFC,TCP
1. Introduction
This document draws heavily from earlier RFCs, in some cases reproducing entire sections of the text of earlier documents [RFC2309, RFC2357]. We have also borrowed heavily from earlier publications addressing the need for end-to-end congestion control [FF99].
2. Current standards on congestion control
IETF standards concerning end-to-end congestion control focus either on specific protocols (., TCP [RFC2581], reliable multicast protocols [RFC2357]) or on the syntax and semantics munications between the end nodes and routers about congestion information (., Explicit Congestion Notification [RFC2481]) or desired quality-of-service (diff-serv)). The role of end-to-end congestion control is also discussed in an Informational RFCon "mendations on Queue Management and Congestion Avoidance in the " [RFC2309]. RFC 2309 mends 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 RFC2309 some of their general discussion of end-to-end congestion control.
In contrast to the RFCs discussed above, this document is a more general discussion of the principles of congestion control. One of the keys to the ess of the has been the congestion avoidance mechanisms of TCP. While TCP is still the dominant transport protocol in the , 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 inc