LAN timeouts / app outage.

[cyberpete]

We have a 3000 user cisco network which is essentially a core 6509/dist5505 /access model. Network bandwidth is nominally low useage and there seems plenty of backplane and BW generally to support user demands. However - we get on a daily basis occasionaly disconnects and time outs to local resources (servers apps etc) for now apps for no apparent reason. I dont know how testable this situation is becuase it may just be that these boxes are occasionally "busy" but the users actually get more than appplciation latency - they get complete timeouts / app outage. I assume the only thing to check is the usual things like duplex mismatches dodgy cables etc? Any input to this appreciated thanks..

[glen.grant]

That would be the first place to start, look at uplinks for utilization problems during the problem periods . Start checking the logs of all switches during the problem periods to see if anything unusual is showing up . Check for things like spanning roots being in the wrong place . Look for any links that have a lot of errors on them . I doubt it is a switch utilization issue though it can't be ruled out as we have seen a user bury a 6500 Sup 720 . Even if its a little busy they shouldn't get timeouts, you may have to get a sniffer and look at it.