A New Internet-Draft is available from the on-line Internet-Drafts directories. Title : Generic Tunnel MTU Determination Author(s) : Fred L. Templin Filename : draft-generic-v6ops-tunmtu-01.txt Pages : 8 Date : 2012-05-24 The tunnel MTU for popular IP-in-IP tunneling mechanisms is currently recommended to be set to 1500 (or less) minus the length of the encapsulation headers when static MTU determination is used. This is to avoid IP fragmentation within the tunnel, but requires the tunnel ingress to either fragment any IP packet larger than the MTU or drop the packet and return an ICMP 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. Fortunately, the "Internet cell size" is 1500 bytes, i.e., the minimum MTU configured by the vast majority of links in the Internet. We also note that these same considerations apply to the encapsulation of any combination of IP- within-IP protocol versions. This document therefore presents a method to boost the tunnel MTU to larger values. A URL for this Internet-Draft is: http://www.ietf.org/internet-drafts/draft-generic-v6ops-tunmtu-01.txt Internet-Drafts are also available by anonymous FTP at: ftp://ftp.ietf.org/internet-drafts/ This Internet-Draft can be retrieved at: ftp://ftp.ietf.org/internet-drafts/draft-generic-v6ops-tunmtu-01.txt The IETF datatracker page for this Internet-Draft is: https://datatracker.ietf.org/doc/draft-generic-v6ops-tunmtu/ _______________________________________________ I-D-Announce mailing list I-D-Announce@ietf.org https://www.ietf.org/mailman/listinfo/i-d-announce Internet-Draft directories: http://www.ietf.org/shadow.html or ftp://ftp.ietf.org/ietf/1shadow-sites.txt
