RFC 2598 (rfc2598) - Page 1 of 11
An Expedited Forwarding PHB
Alternative Format: Original Text Document
Network Working Group V. Jacobson
Request for Comments: 2598 K. Nichols
Category: Standards Track Cisco Systems
K. Poduri
Bay Networks
June 1999
An Expedited Forwarding PHB
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
Abstract
The definition of PHBs (per-hop forwarding behaviors) is a critical
part of the work of the Diffserv Working Group. This document
describes a PHB called Expedited Forwarding. We show the generality
of this PHB by noting that it can be produced by more than one
mechanism and give an example of its use to produce at least one
service, a Virtual Leased Line. A recommended codepoint for this PHB
is given.
A pdf version of this document is available at
ftp://ftp.ee.lbl.gov/papers/ef_phb.pdf
1. Introduction
Network nodes that implement the differentiated services enhancements
to IP use a codepoint in the IP header to select a per-hop behavior
(PHB) as the specific forwarding treatment for that packet [RFC 2474,
RFC 2475]. This memo describes a particular PHB called expedited
forwarding (EF). The EF PHB can be used to build a low loss, low
latency, low jitter, assured bandwidth, end-to-end service through DS
domains. Such a service appears to the endpoints like a point-to-
point connection or a "virtual leased line". This service has also
been described as Premium service [2BIT].
Jacobson, et al. Standards Track