Packetization Layer Path MTU Discovery for Datagram Transports
draft-ietf-tsvwg-datagram-plpmtud-00
Internet Engineering Task Force G. Fairhurst
Internet-Draft T. Jones
Intended status: Standards Track University of Aberdeen
Expires: July 24, 2018 M. Tuexen
I. Ruengeler
Muenster University of Applied Sciences
January 22, 2018
Packetization Layer Path MTU Discovery for Datagram Transports
draft-ietf-tsvwg-datagram-plpmtud-00
Abstract
This document describes a robust method for Path MTU Discovery
(PMTUD) for datagram Packetization layers. The method allows a
Packetization layer (or a datagram application that uses it) to probe
an network path with progressively larger packets to determine a
maximum packet size. The document describes as an extension to RFC
1191 and RFC 8201, which specify ICMP-based Path MTU Discovery for
IPv4 and IPv6. This provides functionally for datagram transports
that is equivalent to the Packetization layer PMTUD specification for
TCP, specified in RFC4821.
When published, this specification updates RFC4821.
Status of this Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 24, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
Fairhurst, Jones, Tuexen ExpireseJuly 24, 2018 [Page 1]
Internet-Draft Datagram PLPMTUD January 2018
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Features required to provide Datagram PLPMTUD . . . . . . . . 6
3.1. PMTU Probe Packets . . . . . . . . . . . . . . . . . . . . 8
3.2. Validation of the current effective PMTU . . . . . . . . . 9
3.3. Reduction of the effective PMTU . . . . . . . . . . . . . 10
4. Datagram Packetization Layer PMTUD . . . . . . . . . . . . . . 10
4.1. Probing . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2. Selecting the Size of a Probe Message . . . . . . . . . . 11
4.3. Verification and use of PTB messages . . . . . . . . . . . 11
4.4. Timers . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.5. Constants . . . . . . . . . . . . . . . . . . . . . . . . 12
4.6. Variables . . . . . . . . . . . . . . . . . . . . . . . . 13
4.7. Selecting Probe Size . . . . . . . . . . . . . . . . . . . 13
4.8. State Machine . . . . . . . . . . . . . . . . . . . . . . 14
5. Specification of Protocol-Specific Methods . . . . . . . . . . 16
5.1. DPLPMTUD for UDP and UDP-Lite . . . . . . . . . . . . . . 16
5.1.1. UDP Options . . . . . . . . . . . . . . . . . . . . . 16
5.1.2. UDP Options required for PLPMTUD . . . . . . . . . . . 16
5.1.2.1. Echo Request Option . . . . . . . . . . . . . . . 16
5.1.2.2. Echo Response Option . . . . . . . . . . . . . . . 17
5.1.3. Sending UDP-Option Probe Packets . . . . . . . . . . . 17
5.1.4. Validating the Path with UDP Options . . . . . . . . . 17
5.1.5. Handling of PTB Messages by UDP . . . . . . . . . . . 17
5.2. DPLPMTUD for SCTP . . . . . . . . . . . . . . . . . . . . 17
5.2.1. SCTP/IP4 and SCTP/IPv6 . . . . . . . . . . . . . . . . 18
5.2.1.1. Sending SCTP Probe Packets . . . . . . . . . . . . 18
5.2.1.2. Validating the Path with SCTP . . . . . . . . . . 18
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