How to debug congestion in network?

[dan_track]

Hi

I'm having a problem with slow connectivity on my LAN, now I don't know what the problem is at the moment and want to start to debug it. My initial guess would be congestion, but I don't know how to start to look for this on my 3750 switches.

Could somebody please point me in the right direction and list some commands I can run and possibly how to store the debug info aswell.

Many Thanks

Dan

[andreas.larsen]

I would start with installing MRTG

http://oss.oetiker.ch/mrtg/

or another bandwith monitor tool. Then let it run for a couple of days towards your switch. To see if you actually have problems with packet forwarding or speed.

Another fine tool is simply show interface Fast 0/1 etc. Look for CRC and interface reset. A high number of that on any interface might point to a faulty port or NIC. Or something as simple as a duplex/speed mismatch.

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