MTUs - Was: Strange public traceroutes return private RFC1918addresses

Thu Feb 5 20:34:29 UTC 2004

> 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.

I believe Rich Seifert once said (on comp.dcom.lans.ethernet) that the
cost of the necessary buffer memory for the first Ethernet cards was a
relevant factor.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no