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Re: exchange point media (was: Re: MAE-EAST Moving? ...)

  • From: Mikael Abrahamsson
  • Date: Thu Jun 15 01:57:29 2000

On Wed, 14 Jun 2000, Brandon Ross wrote:

> While there are certainly shortcomings to using GbE as a public exchange
> infrastructure, I fail to see how a 1500 byte MTU has anything to do with
> it.  In every network I have ever seen, there have very, very rarely been
> any packets larger than 1500 bytes.

One of the major arguments against gigE I've heard is the lower MTU. Yes,
currently there are not much packets that are larger than 1500 due to
endsystems, but if we limit the infrastructure then there'll never be a
larger MTU here. ATM/FDDI/POS and even Token Ring (to mix apples with
oranges) all support larger MTUs and future standards will probably will
as well. Therefore I believe that any shared medium used for exchanging
traffic should also have the same capabilities. Larger packets mean fewer
forwarding/routing decisions per second for the same megabit rate of

Think ahead 3-5 years, do we really want to stick with the 1500 MTU just
because this limitation is built in into the backbone infrastructure?

I have received a few emails stating that several hardware vendors support
jumbo frames on gigE. The question whether cisco does as well immediately
pops up. So far nobody has mentioned their name as one that does support
jumbo frames.

Mikael Abrahamsson    email: [email protected]