art@ACC.ARPA (10/18/85)
> > About a week or so after this change was made we started having > problems. About every 2-4 weeks suddenly every machine on the net > claims that every other machine is down. You can't connect to any > other machines. I have found that if I disconnect the extra length > (recently added) the problem seems to go away. It would seem to not > be a bad ethernet board in one of the machines because I can connect > either one of the 2 IS's ('x' or 'y') onto the net by itself and the > net is still upset. However, I can reconnect the extra length (along > with the 2 machines at the end of it) after about 15-30 min's and > everything is fine for another few weeks. Sometimes the problem > seems to just goes away on its own also! (By the way, a "netstat -i" > says we are sending and receiving lots of packets but getting about > as many input errors as input packets!) > > Has anyone ever seen anything like this? I'm guessing it means we're > too close to the max. length for the ethernet, but I calculate the > total length as around 300 meters and the standard say 500 meters. > If feasable, you might consider having someone test your cable with a Time Domain Reflectometer to make sure you don't have any significant impedance mismatches. You might also try flexing connectors, tranceiver taps and terminators with the system running to look for mechanical problems in the cable. The DELNI is (I believe) V2 Ethernet specs, so verify that the other equiptment is compatible. (V1 and 802.3 have slight differences) "Art Berggreen"<Art@ACC.ARPA> ------