RINA - scott whaps at the nanog hornets nest :-)

Matthew Petach mpetach at netflight.com
Sat Nov 6 16:34:44 CDT 2010


On Sat, Nov 6, 2010 at 2:21 PM, George Bonser <gbonser at seven.com> wrote:
>
...
> As for the configuration differences between units, how does that change
> from the way things are now?  A person configuring a Juniper for 1500
> byte packets already must know the difference as that quirk of including
> the headers is just as true at 1500 bytes as it is at 9000 bytes.  Does
> the operator suddenly become less competent with their gear when they
> use a different value?  Also, a 9000 byte MTU would be a happy value
> that practically everyone supports these days, including ethernet
> adaptors on host machines.

While I think 9k for exchange points is an excellent target, I'll reiterate
that there's a *lot* of SONET interfaces out there that won't be going
away any time soon, so practically speaking, you won't really get more
than 4400 end-to-end, even if you set your hosts to 9k as well.

And yes, I agree with ras; having routers able to adjust on a per-session
basis would be crucial; otherwise, we'd have to ask the peeringdb folks to
add a field that lists each participant's interface MTU at each exchange,
and part of peermaker would be a check that could warn you,
"sorry, you can't peer with network X, your MTU is too small."  ;-P

(though that would make for an interesting deepering notice..."sorry, we
will be unable to peer with networks who cannot support large MTUs
at exchange point X after this date.")

Matt




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