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Per Hop Behavior Identification Codes (RFC3140)

IP.com Disclosure Number: IPCOM000005324D
Original Publication Date: 2001-Jun-01
Included in the Prior Art Database: 2001-Aug-21
Document File: 9 page(s) / 17K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Black: AUTHOR [+4]

Abstract

This document defines a 16 bit encoding mechanism for the identification of differentiated services Per Hop Behaviors in protocol messages. It replaces RFC 2836.

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 20% of the total text.

Network Working Group D. Black Request for Comments: 3140 S. Brim Obsoletes: 2836 B. Carpenter Category: Standards Track F. Le Faucheur

June 2001

Per Hop Behavior Identification Codes

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 (2001). All Rights Reserved.

Abstract

This document defines a 16 bit encoding mechanism for the identification of differentiated services Per Hop Behaviors in protocol messages. It replaces RFC 2836.

Table of Contents

1. Introduction.................................................2 1.1. Usage Scenarios............................................2 2. Encoding.....................................................3 3. Signalling the Class Selector Codepoints.....................4 4. IANA Considerations..........................................5 5. Security Considerations......................................5 Changes from RFC 2836...........................................5 Acknowledgements................................................6 References......................................................6 Authors' Addresses..............................................6 Intellectual Property...........................................7 Full Copyright Statement........................................8

Black, et al. Standards Track [Page 1]

RFC 3140 Per Hop Behavior Identification Codes June 2001

1. Introduction

Differentiated Services [RFC 2474, RFC 2475] introduces the notion of Per Hop Behaviors (PHBs) that define how traffic belonging to a particular behavior aggregate is treated at an individual network node. In IP packet headers, PHBs are not indicated as such; instead Differentiated Services Codepoint (DSCP) values are used. There are only 64 possible DSCP values, but there is no such limit on the number of PHBs. In a given network domain, there is a locally defined mapping between DSCP values and PHBs. Standardized PHBs recommend a DSCP mapping, but network operators may choose alternative mappings.

In some cases it is necessary or desirable to identify a particular PHB in a protocol message, such as a message negotiating bandwidth management or path selection, especially when such messages pass between management domains. Examples where work is in progress include communication between bandwidth brokers, and MPLS support of diffserv.

In certain cases, what needs to be identified is not an individual PHB, but a set of PHBs. One example is a set of PHBs that must follow the same physical path to prevent re-ordering. An instance of th...