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An Expedited Forwarding PHB (RFC2598)

IP.com Disclosure Number: IPCOM000003185D
Original Publication Date: 1999-Jun-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 13 page(s) / 22K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

V. Jacobson: AUTHOR [+3]

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.

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This is the abbreviated version, containing approximately 12% of the total text.

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 [RFC2474,

RFC2475]. 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].

Loss, latency and jitter are all due to the queues traffic

experiences while transiting the network. Therefore providing low

loss, latency and jitter for some traffic aggregate means ensuring

that the aggregate sees no (or very small) queues. Queues arise when

(short-term) traffic arrival rate exceeds departure rate at some

node. Thus a service that ensures no queues for some aggregate is

equivalent to bounding rates such that, at every transit node, the

aggregate's maximum arrival rate is less than that aggregate's

minimum departure rate.

Creating such a...