Browse Prior Art Database

Assured Forwarding PHB Group (RFC2597)

IP.com Disclosure Number: IPCOM000003184D
Original Publication Date: 1999-Jun-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 8 page(s) / 22K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Heinanen: AUTHOR [+4]

Abstract

This document defines a general use Differentiated Services (DS) [Blake] Per-Hop-Behavior (PHB) Group called Assured Forwarding (AF). The AF PHB group provides delivery of IP packets in four independently forwarded AF classes. Within each AF class, an IP packet can be assigned one of three different levels of drop precedence. A DS node does not reorder IP packets of the same microflow if they belong to the same AF class.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 13% of the total text.

Network Working Group J. Heinanen

Request for Comments: 2597 Telia Finland

Category: Standards Track F. Baker

Cisco Systems

W. Weiss

Lucent Technologies

J. Wroclawski

MIT LCS

June 1999

Assured Forwarding PHB Group

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

This document defines a general use Differentiated Services (DS)

[Blake] Per-Hop-Behavior (PHB) Group called Assured Forwarding (AF).

The AF PHB group provides delivery of IP packets in four

independently forwarded AF classes. Within each AF class, an IP

packet can be assigned one of three different levels of drop

precedence. A DS node does not reorder IP packets of the same

microflow if they belong to the same AF class.

1. Purpose and Overview

There is a demand to provide assured forwarding of IP packets over

the Internet. In a typical application, a company uses the Internet

to interconnect its geographically distributed sites and wants an

assurance that IP packets within this intranet are forwarded with

high probability as long as the aggregate traffic from each site does

not exceed the subscribed information rate (profile). It is

desirable that a site may exceed the subscribed profile with the

understanding that the excess traffic is not delivered with as high

probability as the traffic that is within the profile. It is also

important that the network does not reorder packets that belong to

the same microflow, as defined in [Nichols], no matter if they are in

or out of the profile.

Assured Forwarding (AF) PHB group is a means for a provider DS domain

to offer different levels of forwarding assurances for IP packets

received from a customer DS domain. Four AF classes are defined,

where each AF class is in each DS node allocated a certain amount of

forwarding resources (buffer space and bandwidth). IP packets that

wish to use the services provided by the AF PHB group are assigned by

the customer or the provider DS domain into one or more of these AF

classes according to the services that the customer has subscribed

to. Further background about this c...