IPv6 Minimum Path MTU Hop-by-Hop Option
draft-ietf-6man-mtu-option-02

Document Type Active Internet-Draft (6man WG)
Last updated 2020-03-09
Replaces draft-hinden-6man-mtu-option
Stream IETF
Intended RFC status (None)
Formats plain text html xml pdf htmlized (tools) htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state I-D Exists
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                          R. Hinden
Internet-Draft                                      Check Point Software
Intended status: Experimental                               G. Fairhurst
Expires: 10 September 2020                        University of Aberdeen
                                                            9 March 2020

                IPv6 Minimum Path MTU Hop-by-Hop Option
                     draft-ietf-6man-mtu-option-02

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 recorded MTU
   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 10 September 2020.

Copyright Notice

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

Hinden & Fairhurst      Expires 10 September 2020               [Page 1]
Internet-Draft               Path MTU Option                  March 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
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Motivation and Problem Solved . . . . . . . . . . . . . . . .   4
   3.  Requirements Language . . . . . . . . . . . . . . . . . . . .   5
   4.  Applicability Statements  . . . . . . . . . . . . . . . . . .   5
   5.  IPv6 Minimum Path MTU Hop-by-Hop Option . . . . . . . . . . .   6
   6.  Router, Host, and Transport Behaviors . . . . . . . . . . . .   7
     6.1.  Router Behaviour  . . . . . . . . . . . . . . . . . . . .   7
     6.2.  Host Behavior . . . . . . . . . . . . . . . . . . . . . .   7
     6.3.  Transport Behavior  . . . . . . . . . . . . . . . . . . .  10
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  11
   10. Change log [RFC Editor: Please remove]  . . . . . . . . . . .  12
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  13
     11.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Appendix A.  Planned Experiments  . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   This draft proposes a new Hop-by-Hop Option to be used to record the
   minimum MTU along the forward path between the source and destination
   hosts.  The source host creates a packet with this Hop-by-Hop Option
   and fills the Reported PMTU Field in the option with the value of the
   MTU for the outbound link that will be used to forward the packet
   towards the destination.

   At each subsequent hop where the option is processed, the router
   compares the value of the Reported PMTU in the option and the MTU of
   its outgoing link.  If the MTU of the outgoing link is less than the
   Reported PMTU specified in the option, it rewrites the value in the
   Option Data with the smaller value.  When the packet arrives at the
   destination host, the destination host can send the minimum reported
   PMTU value back to the source host using the Return PMTU field in the
   option.

Hinden & Fairhurst      Expires 10 September 2020               [Page 2]
Show full document text