(back to RRG in accordance with Lixia's request) On 2007-09-13 13:58, Dino Farinacci wrote:
So there is no way our network could run on a MTU of 4470 or even higher any time soon.Then you don't deploy ITRs or you deploy fragmenting-ITRs.[..]In practice, this is not really a problem. Hosts typically do not originate IP packets larger than 1500 bytes. And second, a survey has been taken (from a list of ISPs, see Acknowledgement section) where nearly all ISP link MTUs are either 4470 bytes or support Ethernet jumbo frames of 9000 bytes. Therefore, we don't anticipate any problems with prepending additional headers.This is handwaving, and not a good basis for research work.You are right, we are trying to make a decision and are doing engineering now past the research stage. ;-)
I just re-read RFC 2460 section 5. Admittedly things are less
clear for IPv4, but it seems clear that IPv6 senders should not
exceed 1280 bytes (pre-encapsulation) unless they have succeeded
in discovering a larger path MTU.
Brian
--
to unsubscribe send a message to rrg-request@psg.com with the
word 'unsubscribe' in a single line as the message text body.
archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg