IPv6 Minimum Path MTU Hop-by-Hop Option
draft-ietf-6man-mtu-option-04

Document Type Active Internet-Draft (6man WG)
Authors Bob Hinden  , Gorry Fairhurst 
Last updated 2020-10-23
Replaces draft-hinden-6man-mtu-option
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Network Working Group                                          R. Hinden
Internet-Draft                                      Check Point Software
Intended status: Experimental                               G. Fairhurst
Expires: 26 April 2021                            University of Aberdeen
                                                         23 October 2020

                IPv6 Minimum Path MTU Hop-by-Hop Option
                     draft-ietf-6man-mtu-option-04

Abstract

   This document specifies a new Hop-by-Hop IPv6 option that is used to
   record the minimum Path MTU along the forward path between a source
   host to a destination host.  This collects a minimum Path MTU
   recorded along the path to the destination.  The value can then be
   communicated back to the source using the return Path MTU field in
   the option.

   This Hop-by-Hop option is intended to be used in environments like
   Data Centers and on paths between Data Centers, to allow them to
   better take advantage of paths able to support a large Path MTU.  The
   method could also be useful in other environments, including the
   general Internet.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 26 April 2021.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Hinden & Fairhurst        Expires 26 April 2021                 [Page 1]
Internet-Draft               Path MTU Option                October 2020

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Simplified BSD License text
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   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Example Operation . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Use of the IPv6 Hop-by-Hop Options Header . . . . . . . .   4
   2.  Motivation and Problem Solved . . . . . . . . . . . . . . . .   5
   3.  Requirements Language . . . . . . . . . . . . . . . . . . . .   6
   4.  Applicability Statements  . . . . . . . . . . . . . . . . . .   6
   5.  IPv6 Minimum Path MTU Hop-by-Hop Option . . . . . . . . . . .   6
   6.  Router, Host, and Transport Behaviors . . . . . . . . . . . .   7
     6.1.  Router Behavior . . . . . . . . . . . . . . . . . . . . .   7
     6.2.  Host Behavior . . . . . . . . . . . . . . . . . . . . . .   8
     6.3.  Transport Behavior  . . . . . . . . . . . . . . . . . . .   8
       6.3.1.  Including the Option in an Outgoing Packet  . . . . .   8
       6.3.2.  Validation by the Upper Layer Protocol  . . . . . . .  10
       6.3.3.  Receiving the Option  . . . . . . . . . . . . . . . .  10
       6.3.4.  Using the Rtn-PMTU Field  . . . . . . . . . . . . . .  11
       6.3.5.  Detection of Dropping Packets that include the
               Option  . . . . . . . . . . . . . . . . . . . . . . .  12
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
     8.1.  Network Layer Host Processing . . . . . . . . . . . . . .  13
     8.2.  Validating use of the Option Data . . . . . . . . . . . .  13
     8.3.  Direct use of the Rtn-PMTU Value  . . . . . . . . . . . .  14
     8.4.  Using the Rtn-PMTU Value as a Hint for Probing  . . . . .  14
     8.5.  Impact of Middleboxes . . . . . . . . . . . . . . . . . .  15
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  15
   10. Change log [RFC Editor: Please remove]  . . . . . . . . . . .  15
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  17
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  17
     11.2.  Informative References . . . . . . . . . . . . . . . . .  17
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  18

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