Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!munnari.oz.au!bruce!monu1!monu6!dave From: dave@monu6.cc.monash.edu.au (Dave Schwarz) Newsgroups: comp.dcom.lans Subject: Re: Ethernet collisions Summary: collisions on ethernet Keywords: LANalyzer Ethernet Message-ID: <1990Dec5.022111.25685@monu6.cc.monash.edu.au> Date: 5 Dec 90 02:21:11 GMT References: <467@pirates.UUCP> Organization: Monash Uni Caulfield Campus (Was Chisholm Inst of Tech) Lines: 31 In article <467@pirates.UUCP>, bob@pirates.UUCP (Bob Fawcett) writes: > I would like to know what can cause excessive collisions on Ethernet. I > realize that collisions are a fact of life on ethernet. > My net analyzer shows a large number of local collisions (as high as 20%). > I can't isolate to just one or two machines. I also don't have any one > machine which is completely non functional. In other words I haven't > nailed it down to a problem with one machine (bad card or ?). What other > things should I look for? Ground problems? My cable scanner doesn't show > any bad segments of cable. > MOst of the machines are on Thinnet. There is fiber between buildings. > Total of about 150 stations campus wide. > > Any Ideas? Try looking at any AUI cables you may have, we just had a very simmilar problem with one of out subnets. The transfer rate had dropped from aprox 200Kbytes/sec to 20Kbytes/sec. The problem only appeared when we swapped and Dempa for a Delni (2 dec products) both were driving a 20m piece of AUI cable connected to a F/O repeater. When we swapped we got the reduction in bandwidth, after much checking we discovered that the cable was to long, we shortened it back to 5 meters and it worked ? It seemed that the Delni didn't have enought omph to drive long bits of cable. dave.... -- Dave Schwarz @ Monash Uni Caulfield Campus This space now for hire 900 Dandynong Rd,East Caulfield,Vic,Australia (and I know that DANDENONG dave@monu6.cc.monash.edu.au doesn't have a Y in it !) Dave@banyan.cc.monash.edu.au Dave@vx24.cc.monash.edu.au (Yuk a vax)