Ethernet is not designed for huge LANs. If you want that you need to make significant changes - http://www.cl.cam.ac.uk/~mas90/MOOSE/
Hm:
"Our object is to design a communication system which can grow smoothly to accommodate several buildings full of personal computers and the facilities needed for their support."
Ethernet: Distributed Packet Switching for Local Computer Networks Robert M. Metcalfe and David R. Boggs Communications of the ACM Volume 19 Issue 7, July 1976
So let's change it slightly: Ethernet is not designed for huge broadcast domains. How big is huge? To some degree it depends on how broadcast "chatty" the protocols used are - but there's also the matter of having a size which makes it possible to troubleshoot. Personally I'd prefer an upper limit of a few hundred computers. Steinar Haug, Nethelp consulting, sthaug@nethelp.no