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