Re: [BEHAVE] Amount of fragmentation resulting from translation

[Brian E Carpenter <brian.e.carpenter at gmail.com>]

On 2009-10-31 22:18, Iljitsch van Beijnum wrote:
> On 31 okt 2009, at 02:58, Brian E Carpenter wrote:
> 
>> BTW, the MTU data observed in draft-defeche-ipv6-traffic-in-p2p-networks
>> strongly support this for today's IPv6 world. Average observed IPv4
>> MTU was 1498 bytes and average observed IPv6 MTU was 1289, obviously
>> telling us that 1280 is the dominant value in practice (at least
>> for hosts running BitTorrent). So it's not only the safe value to use,
>> but it's also not very sub-optimal.
> 
> Disagree.
> 
> I've been looking at IPv6 in BitTorrent a bit, and nearly all peers
> participating in BitTorrent over IPv6 use 6to4. Obviously there will be
> little overlap between 6to4 users and NAT64 users...

Actually draft-defeche shows that Teredo is twice as important as 6to4,
but yes, most of the 1280s come from automatic tunnels. But I don't get
your argument: if the PMTU is limited to 1280 anywhere in the IPv6 domain,
it's a problem, for some of the deployment scenarios for
draft-ietf-behave-v6v4-xlate.

> 
> I'll see if I can dig up some info from people visiting my websites over
> IPv6.

Yes, that would be valuable.

   Brian