How to monitor bandwidth on LAN - unusual traffic

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Sep 18th, 2008
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I am looking for a step-by-step guide where I would be able to look at my 3560 and monitor bandwidth and utilization. Recently, we had a minor adware issue, and I had to depend on my WAN team to determine which machine it was coming from.

Is there some commands I can use to find this out?

I'm looking for something easy if possible and not too elaborate.

Thank you,


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glen.grant Thu, 09/18/2008 - 08:50
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Use the "show controllers utilization" command to see the utilization for each every port and how busy the actual switch fabric is , very useful .

svillardi Thu, 09/18/2008 - 08:58
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So, I would run that at the core, then figure out which port is causing the problem and then do a sho cdp n for the port and then go to that access switch and do it again and then find the port and then do a show mac address-table to find the mac address then look in my DHCP server to see the mac?

glen.grant Thu, 09/18/2008 - 09:13
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That command works on the standalone switches like the 3560 and 3750 , will not work on a chassis based switch .

svillardi Thu, 09/18/2008 - 09:15
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so if i have a 6509 and a 4507, which I do, what do I use then?

YM13-RIPE Thu, 09/18/2008 - 11:35
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You can use a command "storm-control action trap" on all interfaces and receive the prevention of excess of the exposed threshold of recycling of port on unicast|broadcasr|multicast.

Better to use MRTG for a portrayal of history of recycling of all ports of the switchboard with use of report SNMP and the subsequent viewing of the received schedules for the analysis. But in this case it is possible to catch only anomalies in loading of channels. The Storm to trace not will be possible from for inaccessibility of the switch.


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