IPv6 day and tunnels

Tue Jun 5 21:44:22 UTC 2012

Templin, Fred L wrote:

> General statement for IPv6-in-IPv4 tunneling, yes. But
> inner fragmentation applies equally for *-in-* tunneling.
> 
>> Even though you assume tunnel MTU 1500B
> 
> What I am after is a tunnel MTU of infinity. 1500 is
> the minimum packet size that MUST get through. 1501+
> packets are admitted into the tunnel unconditionally
> in hopes that they MIGHT get through.

Infinity? You can't carry 65516B in an IPv4 packet.

> My document also allows for outer fragmentation on the
> inner fragments. But, like the RFC4213-derived IPv6
> transition mechanisms treats outer fragmentation as
> an anomalous condition to be avoided if possible - not
> a steady state operational approach. See Section 3.2
> of RFC4213.

Instead, see the last two lines in second last slide of:

   http://meetings.apnic.net/__data/assets/file/0018/38214/pathMTU.pdf

It is a common condition.

					Masataka Ohta