6rd Tunnel MTU
draft-foo-v6ops-6rdmtu-03

 
Document
Type Expired Internet-Draft (individual)
Last updated 2014-08-18 (latest revision 2014-02-14)
Stream (None)
Intended RFC status (None)
Formats
Expired & archived
plain text pdf html
Stream
Stream state (No stream defined)
Document shepherd No shepherd assigned
IESG
IESG state Expired
Telechat date
Responsible AD (None)
Send notices to (None)

Email authors IPR References Referenced by Nits Search lists

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at
https://www.ietf.org/archive/id/draft-foo-v6ops-6rdmtu-03.txt

Abstract

The tunnel MTU on 6rd Provider Edge (PE) and Consumer Edge (CE) routers is currently recommended to be set to 1480. This is to avoid IPv4 fragmentation within the tunnel, but requires the tunnel ingress to drop any IPv6 packet larger than 1480 bytes and return an ICMPv6 Packet Too Big (PTB) message. Concerns for operational issues with both IPv4 and IPv6 Path MTU Discovery point to the possibility of MTU-related black holes when a packet is dropped due to an MTU restriction somewhere in the Internet. Fortunately, the "Internet cell size" is 1500 bytes (i.e., the minimum MTU configured by the vast majority of links in the Internet) so if the 6rd PE router can set a tunnel MTU of at least 1500 bytes the MTU issues are alleviated. This document specifies methods that can be employed to support these larger sizes.

Authors

Fred Templin (fltemplin@acm.org)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)