Thoughts on increasing MTUs on the internet

Thu Apr 12 12:03:48 UTC 2007

On Thu, 12 Apr 2007, Saku Ytti wrote:

> IXP peeps, why are you not offering high MTU VLAN option?

Netnod in Sweden offer MTU 4470 option.

Otoh it's not so easy operationally since for instance Juniper and Cisco 
calculates MTU differently.

But I don't really see it beneficial to try to up the endsystem MTU to 
over standard ethernet MTU, if you think it's operationally troublesome 
with PMTUD now, imagine when everybody is running different MTU.

Biggest benefit would be if the transport network people run PPPoE and 
other tunneled traffic over, would allow for whatever MTU needed to carry 
unfragmented 1500 byte tunneled packets, so we could assure that all hosts 
on the internet actually have 1500 IP MTU transparently.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se