Path: utzoo!attcan!uunet!munnari.oz.au!bruce!trlluna!rhea.trl.oz.au!gotch From: gotch@rhea.trl.oz.au (Rob Gotch) Newsgroups: comp.dcom.lans Subject: Ethernet/Optical link locking up Message-ID: <1864@trlluna.trl.oz> Date: 6 Jul 90 00:41:52 GMT Sender: news@trlluna.trl.oz Lines: 52 Our Ethernet looks like this: Building 1 Building 2 Building 3 Building 4 # # # # | | | | | | | | @-----derep======derep-----@ | | | | | | | | | | | # | | | | | @-----derep=====================derep-----@ | | | | | | | | # | | | @-----derep====================================derep-----@ | | | | # # | is thickwire backbone @ is ANC-20 dual port transceiver (MAU) - is transceiver (MAU) cable = is duplex optical fibre # is 50 ohm termination Our problem is that, occasionally, one of the repeated links locks up. Close inspection of the equipment reveals that the ANC-20 MAU's at each end of the affected link show the collision detect light hard on. As soon as we disconnect one of the AUI cables to either MAU the collision lights go out and upon reconnecting the AUI cable the link begins to operate normally - until next time :-(. As far as I know, we have built our network well within the design spec, in terms of cable lengths, fibre loss budget, etc. The problem has occured on two of the three links so it may not be a single faulty device. The impression I get is that the fault is in one of the ANC-20's although this would implicate more than one device. Has anyone else experienced similar problems? If so, how were your problems fixed? Does anyone have any ideas about how to identify and eliminate our problem? Thanks in advance, Rob. ------------------------------------------------------------------------ Rob Gotch (r.gotch@trl.oz.au) | And the son of God died, which is immediately Financial & Computing Services | credible because it is absurd. And buried, he Telecom Research Laboratories | rose again, which is certain because it is 770 Blackburn Rd Clayton Vic | impossible. Tertullian 160 AD.