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Re: MTU of the Internet?

  • From: Jay R. Ashworth
  • Date: Fri Feb 06 21:03:32 1998

On Fri, Feb 06, 1998 at 10:50:31AM -0800, Tony Hain wrote:
> This thread has drifted all over the place and the only conclusions I can
> see are:
> The core infrastructure MTU is >= 1500
> People are telling clients to set their Win95 MTU to 576

People are asserting that Win98 comes with it's MTU set this low, which
appears to be generally considered to be a bad idea.

> PMTU is randomly broken by clueless filtering
> Some dial-access devices are buffer limited
> A small MTU (53 byte?) would increase perceived response at the expense of
> performance

Browsers, and other software which open multiple connections should
temper their connection counts based on the size of the perceived pipe;
ie: some connect-level heuristics to do proper PMTUD and _make the
answer available to applications_ would probably be useful.

> I have been an advocate of the bigger defaults is better camp, but there is
> a real concern that the wrong values could actually cause more damage than
> their gain is worth. If the above list is incorrect or incomplete it would
> be useful for people to constructively tell Peter that now. 

That's the only one that I can see that you missed.  Any effort
expended to improve the quality of the default stack in Win9X would
probably be A Good Thing... given the current population of the net.

-- jra
Jay R. Ashworth                                                [email protected]
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