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A Needle in a Hay Stack: Network Slow as if being flooded!

We have a network made up of multiple vlans on multipe types of switches and hubs (2950, 2924, 2600, 1900, 5000, 4000). I'm not getting any critical errors on switches through CWSI however network starts to crawl. Seems to affect IP primarily. Will crawl for weeks then RSM (RSM on 5000) will eventually be overloaded and bring entire network to it's knees.

We are looking at port settings compared to device NIC settings. Windows Security Patches and Virus Updates have been applied.

Any ideas? Sniffing isn't turning anything up.

Any help would be appreciated. Thanks -- Darney

Cisco Employee

Re: A Needle in a Hay Stack: Network Slow as if being flooded!

Doing file transfers should help spot the problem. Take two pc's with a crossover cable and time a 200 meg file transfer. That would be your baseline. Then put the pc's in there own (2 port} vlan on the switch. There should be little or no difference in the transfer time. Keep adding things to the test (Put the PC's in two separate vlans on the same switch, then move one pc one switch away, etc...).

At some point you will see the problem and then backup one step and you will not see the problem.

Then you have the problem spotted.

If this fails open a case with TAC.

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