RFC 1254 (rfc1254) - Page 1 of 25

Gateway Congestion Control Survey

Network Working Group                                          A. Mankin
Request for Comments: 1254                                         MITRE
                                                         K. Ramakrishnan
                                           Digital Equipment Corporation
                                                                 Editors
                                                             August 1991


                   Gateway Congestion Control Survey

Status of this Memo

   This memo provides information for the Internet community.  It is a
   survey of some of the major directions and issues.  It does not
   specify an Internet standard.  Distribution of this memo is
   unlimited.

Abstract

   The growth of network intensive Internet applications has made
   gateway congestion control a high priority.  The IETF Performance and
   Congestion Control Working Group surveyed and reviewed gateway
   congestion control and avoidance approaches.  The purpose of this
   paper is to present our review of the congestion control approaches,
   as a way of encouraging new discussion and experimentation.  Included
   in the survey are Source Quench, Random Drop, Congestion Indication
   (DEC Bit), and Fair Queueing.  The task remains for Internet
   implementors to determine and agree on the most effective mechanisms
   for controlling gateway congestion.

1.  Introduction

   Internet users regularly encounter congestion, often in mild forms.
   However, severe congestion episodes have been reported also; and
   gateway congestion remains an obstacle for Internet applications such
   as scientific supercomputing data transfer.  The need for Internet
   congestion control originally became apparent during several periods
   of 1986 and 1987, when the Internet experienced the "congestion
   collapse" condition predicted by Nagle [Nag84].  A large number of
   widely dispersed Internet sites experienced simultaneous slowdown or
   cessation of networking services for prolonged periods.  BBN, the
   firm responsible for maintaining the then backbone of the Internet,
   the ARPANET, responded to the collapse by adding link capacity
   [Gar87].

   Much of the Internet now uses as a transmission backbone the National
   Science Foundation Network (NSFNET). Extensive monitoring and
   capacity planning are being done for the NSFNET backbone; still, as



Performance and Congestion Control Working Group