RFC 2638 (rfc2638) - Page 1 of 26

A Two-bit Differentiated Services Architecture for the Internet

Network Working Group                                          K. Nichols
Request for Comments: 2638                                    V. Jacobson
Category: Informational                                             Cisco
                                                                 L. Zhang
                                                                     UCLA
                                                                July 1999


    A Two-bit Differentiated Services Architecture for 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 (1999).  All Rights Reserved.

Abstract

   This document was originally submitted as an internet draft in
   November of 1997. As one of the documents predating the formation of
   the IETF's Differentiated Services Working Group, many of the ideas
   presented here, in concert with Dave Clark's subsequent presentation
   to the December 1997 meeting of the IETF Integrated Services Working
   Group, were key to the work which led to RFCs 2474 and 2475 and the
   section on allocation remains a timely proposal. For this reason, and
   to provide a reference, it is being submitted in its original form.
   The forwarding path portion of this document is intended as a record
   of where we were at in late 1997 and not as an indication of future
   direction.

   The postscript version of this document includes Clark's slides as an
   appendix. The postscript version of this document also includes many
   figures that aid greatly in its readability.

1. Introduction

   This document presents a differentiated services architecture for the
   internet. Dave Clark and Van Jacobson each presented work on
   differentiated services at the Munich IETF meeting [2,3]. Each
   explained how to use one bit of the IP header to deliver a new kind
   of service to packets in the internet. These were two very different
   kinds of service with quite different policy assumptions. Ensuing
   discussion has convinced us that both service types have merit and
   that both service types can be implemented with a set of very similar



Nichols, et al.              Informational