Re: Path MTU for draft-ietf-v6ops-mech-v2-00.txt

[itojun@iijlab.net]

>> 	1280 is the only link MTU requirement value appears in RFC2460, and it
>> 	is the minimum required value for any IPv6 links (which does not
>> 	require wacky fragmentation header rule at the end of 2460 section 5).
>> 	i dunno what word other than "simple" would capture this.
>Correct me if wrong, but it appears the fragmentation header rule must be 
>included also for the case of MTU 1280 when the IPv4 IP-IP tunnels have DF 
>bit set.  Which appears to be the typical case, e.g. one major router 
>vendor doesn't even support anything else.

	i don't understand your scenario.  even if there's IPv4-over-IPv4
	tunnel with outer DF bit set, ICMPv4 too big won't get propagated
	to IPv6-over-IPv4 endpoint, nor IPv6 source.

itojun