North American Network Operators Group
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Re: Thoughts on increasing MTUs on the internet

  • From: Iljitsch van Beijnum
  • Date: Thu Apr 12 07:06:57 2007

On 12-apr-2007, at 12:02, Pierfrancesco Caci wrote:

wouldn't that work only if the switch in the middle of your neat
office lan is a real switch (i.e. not flooding oversize packets to
hosts that can't handle them, possibly crashing their NIC drivers) and
it's itself capable of larger MTUs?

Well, yes, being compatible with stuff that doesn't support larger packets pretty much goes without saying. I don't think there is any need to worry about crashing drivers, packets that are longer than they should are a common error condition that drivers are supposed to handle without incident. (They often keep a "giant" count.)

A more common problem would be two hosts that support jumboframes with a switch in the middle that doesn't. So it's necessary to test for this and avoid excessive numbers or large packets when something in the middle doesn't support them.