Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site lll-crg.ARpA Path: utzoo!linus!philabs!cmcl2!harvard!seismo!lll-crg!medin From: medin@lll-crg.ARpA (Milo Medin) Newsgroups: net.dcom Subject: Re: Ethernet/Fiber Optic Repeaters Message-ID: <959@lll-crg.ARpA> Date: Sun, 3-Nov-85 20:20:43 EST Article-I.D.: lll-crg.959 Posted: Sun Nov 3 20:20:43 1985 Date-Received: Tue, 5-Nov-85 21:09:33 EST References: <360@nrcvax.UUCP> Organization: Lawrence Livermore Labs, CRG, Livermore Ca Lines: 27 Summary: codenoll repeaters Since they were mentioned, I thought I'd throw in some experience I have had with the codenoll 3030 fiber modems in use with repeaters. In short, they dont work. The 3030's by themselves work OK, as long as you plug them into an ethernet controller of the appropriate version number, things work out. To go long distances though, they deactivate CD. Depending on loading, this may not be a problem, but its ugly in any case. BGut when you combine them with a repeater such as a DEC DEREP-AA (local repeater), they don't work. Note we got our DEREP by buying it from codenoll as part of their repeater package. You pay $2000 extra for having a codenoll sticker on it, there are no internal differences. Well, the thing simply wouldnt work at all with the 3030's. After a long debate with the manufacturer, they came out and tried to make it work themselves. After cutting various things in the 3030's, it came up. BUT, we were showing anywhere from 16-50% collisions on the cable, where it used to be 1%! ANd, the really weird thing was that initailly deffered packets were close to zero, and multiple collisions were very high. We took the thing off the link and sent it back. In short, don't buy Codenoll for fiber-coax technology! Milo Medin NASA Ames Research Center