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Path MTU Discovery for IP version 6 (RFC1981)

IP.com Disclosure Number: IPCOM000004261D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 12 page(s) / 32K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. McCann: AUTHOR [+2]

Abstract

This document describes Path MTU Discovery for IP version 6. It is largely derived from RFC 1191, which describes Path MTU Discovery for IP version 4.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 9% of the total text.

Network Working Group J. McCann

Request for Comments: 1981 Digital Equipment Corporation

Category: Standards Track S. Deering

Xerox PARC

J. Mogul

Digital Equipment Corporation

August 1996

Path MTU Discovery for IP version 6

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.

Abstract

This document describes Path MTU Discovery for IP version 6. It is

largely derived from RFC 1191, which describes Path MTU Discovery for

IP version 4.

Table of Contents

1. Introduction.................................................2

2. Terminology..................................................2

3. Protocol overview............................................3

4. Protocol Requirements........................................4

5. Implementation Issues........................................5

5.1. Layering...................................................5

5.2. Storing PMTU information...................................6

5.3. Purging stale PMTU information.............................8

5.4. TCP layer actions..........................................9

5.5. Issues for other transport protocols......................11

5.6. Management interface......................................12

6. Security Considerations.....................................12

Acknowledgements...............................................13

Appendix A - Comparison to RFC 1191............................14

References.....................................................14

Authors' Addresses.............................................15

1. Introduction

When one IPv6 node has a large amount of data to send to another

node, the data is transmitted in a series of IPv6 packets. It is

usually preferable that these packets be of the largest size that can

successfully traverse the path from the source node to the

destination node. This packet size is referred to as the Path MTU

(PMTU), and it is equal to the minimum link MTU of all the links in a

path. IPv6 defines a standard mechanism for a node to discover the

PMTU of an arbitrary path.

IPv6 nodes SHOULD implement Path MTU Discovery in order to discover

and take advantage of paths with PMTU greater than the IPv6 minimum

link MTU [IPv6-SPEC]. A minimal IPv6 implementation (e.g., in a boot

ROM) may choose to omit implementation of Path MTU Discovery.

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