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Re: Thoughts on increasing MTUs on the internet

  • From: Steven M. Bellovin
  • Date: Thu Apr 12 09:28:46 2007

On Thu, 12 Apr 2007 11:20:18 +0200
Iljitsch van Beijnum <iljitsch@xxxxxxxxx> wrote:

> 
> Dear NANOGers,
> 
> It irks me that today, the effective MTU of the internet is 1500
> bytes, while more and more equipment can handle bigger packets.
> 
> What do you guys think about a mechanism that allows hosts and
> routers on a subnet to automatically discover the MTU they can use
> towards other systems on the same subnet, so that:
> 
> 1. It's no longer necessary to limit the subnet MTU to that of the
> least capable system
> 
> 2. It's no longer necessary to manage 1500 byte+ MTUs manually
> 
> Any additional issues that such a mechanism would have to address?
> 

Last I heard, the IEEE won't go along, and they're the ones who
standardize 802.3.

A few years ago, the IETF was considering various jumbogram options.
As best I recall, that was the official response from the relevant
IEEE folks: "no". They're concerned with backward compatibility.  

Perhaps that has changed (and I certainly) don't remember who sent that
note.  


		--Steve Bellovin, http://www.cs.columbia.edu/~smb