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Re: MTUs - Was: Strange public traceroutes return private RFC1918 addresses

  • From: Laurence F. Sheldon, Jr.
  • Date: Thu Feb 05 15:53:56 2004

Warren Kumari wrote:
> Ok, I know that this is getting away from the original thread, but I've
> always wondered this...
> Why is the MTU on Ethernet 1500 bytes? I have looked through various
> docs (eg IEEE Std 802.x) and can find where maxUntaggedFrameSize is
> listed as 1518 octets, but there is no mention of why this was chosen.
> I know where the minimum frame size comes from (CSMA/CD and propagation
> times, etc), but the maximum frame size number sounds fairly arbitrary.

Because that was a conveniently large amount of very pricey memory
availble at the time?

Because that was the amount that could be blatted down a 500 meter
hose and get the "CD" part to work at some common clock rate?