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How to monitor packet traffic on Cisco switch?

I have a Cisco 3560G switch at the edge of my network. It has 2 connections out to our single ISP (redundant connections, 1G each, using iBGP, but all to a single source), and then 4 connections to different networks internally.

Overall things work well, but I've noticed the CPU on the switch spiking into the 30% range a bit, not sure if that means we are hitting the limits of the switch and should look at something more powerful.

I noticed that Cisco doesn't provide CPU specs of their switches, just how many packets/second they are rated for (mine is 38.7 Mpps)... I am attaching a graph of the CPU, which we are monitoring via SNMP using PRTG.

Any way I can know if this is packet related, and perhaps I need to upgrade to a higher-end switch?

Thanks.cisco cpu graph
1 Solution
Ken BooneNetwork ConsultantCommented:
well since you are already using PRTG to monitor the CPU why don't you use PRTG to monitor the bandwidth utilization of each of the ports as well.  This way you will know if the CPU spike is happening at peak traffic times.  I wouldn't worry about CPU at 30% at all.  If you are pushing 90% you got a problem.  But I don't you have anything to worry about at 30%

Here is a link on how to troubleshoot a high cpu issue.  


I really don't think 30% is anything to worry about from a 3560.  But if I were you and had the time I would want to find out why just so I knew what was going on on my network better ;)
tabushAuthor Commented:
thanks @ken. the CPU spikes don't correlate to traffic spikes. I will read up on the link you sent, and also good to note that 30% isn't something to worry about.

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