IPv6 Packet Truncation
draft-leddy-6man-truncate-05

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Last updated 2018-10-10
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6man                                                            J. Leddy
Internet-Draft                                              Unaffiliated
Intended status: Standards Track                               R. Bonica
Expires: April 15, 2019                                 Juniper Networks
                                                             I. Lubashev
                                                     Akamai Technologies
                                                        October 12, 2018

                         IPv6 Packet Truncation
                      draft-leddy-6man-truncate-05

Abstract

   This document defines IPv6 packet truncation procedures.  These
   procedures make Path MTU Discovery (PMTUD) more reliable.  Upper-
   layer protocols can leverage these procedures in order to take
   advantage of large MTUs.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on April 15, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   5
   3.  Operational Considerations  . . . . . . . . . . . . . . . . .   5
   4.  IPv6 Destination Options  . . . . . . . . . . . . . . . . . .   6
     4.1.  The Truncation Eligible Option  . . . . . . . . . . . . .   6
     4.2.  The Truncated Packet Option . . . . . . . . . . . . . . .   7
   5.  Reference Topology  . . . . . . . . . . . . . . . . . . . . .   8
   6.  Truncation Procedures . . . . . . . . . . . . . . . . . . . .   8
   7.  Additional Truncation Considerations  . . . . . . . . . . . .  10
   8.  Backwards Compatibility . . . . . . . . . . . . . . . . . . .  10
   9.  Checksum Considerations . . . . . . . . . . . . . . . . . . .  11
   10. Invalid Packet Types  . . . . . . . . . . . . . . . . . . . .  11
   11. Network Considerations  . . . . . . . . . . . . . . . . . . .  12
   12. Encapsulating Security Payload Considerations . . . . . . . .  12
   13. Extension Header Considerations . . . . . . . . . . . . . . .  13
   14. Security Considerations . . . . . . . . . . . . . . . . . . .  13
   15. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   16. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   17. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     17.1.  Normative References . . . . . . . . . . . . . . . . . .  14
     17.2.  Informative References . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   An Internet path connects a source node to a destination node.  A
   path can contain links and routers.

   Each link is constrained by the number of bytes that it can convey in
   a single IP packet.  This constraint is called the link Maximum
   Transmission Unit (MTU).  IPv6 [RFC8200] requires every link to have
   an MTU of 1280 bytes or greater.  This value is called IPv6 minimum
   link MTU.

   Likewise, each Internet path is constrained by the number of bytes
   that it can convey in a single IP packet.  This constraint is called
   the Path MTU (PMTU).  For any given path, the PMTU is equal to the
   smallest of its link MTUs.

   IPv6 allows fragmentation at the source node only.  If an IPv6 source
   node sends a packet whose length exceeds the PMTU, an intermediate
   node will discard the packet.  In order to prevent this, IPv6 nodes
   can either:

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