fast ethernet limits

Sat Jan 11 08:10:12 UTC 2003

On Fri, 10 Jan 2003, blitz wrote:

> 100 meters is supposedly the limit for ethernet, and "assuming" a 12' 
> floor, your'e around 24 feet over spec.

100 meters is primarily a "timing limit" for half duplex, ie if you're 
running half duplex, how large can your broadcast domain be before you 
risk losing small packets due to the collission not reaching all speakers 
on the wire (and this counting the max number of repeaters in a broadcast 
domain). 100/half will do padding of small packets to achieve just this 
effect.

I've seen 170meter CAT5 100 meg full duplex links working just fine. Of 
course, as stated before, it's an interference thing, if you have a lot of 
noise around the wiring you'll shorten the usable length.

Of course, this is a ethernet chipset issue, but there are definately
chipsets out there capable of electronically driving links much more than
100 meters just fine.

-- 
Mikael Abrahamsson    email: swmike at swm.pp.se