High CPU utilization on C3700 ???

Question

My 3700 router keeps getting high CPU utilization (average 50 - 60 %). When it reached 80% or higher, most web sites got time-out and we lost internet connection. Bandwidth monitor from TimeWarner showing usage just about 40% (4 Mbs/10 Mbs):e0: in from Timewarner telecom 10 Mbse1: out connnected to 4507  with 21 sub interfacesConfig has been changed for years.Few access lists run to prevent sub-int talk together.If you know any reason may lead to CPU high, please let me know. I want to try all solutions befor it gets worse.Thank you in advance!

w1llr0ut34f00d · Accepted Answer

Find out which process is eating CPU.I can give you more info if you can post the result of the following.show process cpu | exclude 0.00- Joe

Jimmy · Answer

Thanks Joe, very useful command I found that CID 33 around 10.5% with IP Input

I also put SolarWin in to monitor all interfaces of the router and noticed that 1 interface that has about 6 computers connected use 1.71 Mbs while the other interface with over 200 employees use only 0.3 Mbs. Do you think we got virus in the vlan connected to high usage bandwidth?

Thanks

w1llr0ut34f00d · Answer

Virus is always usual suspect.With 10% IP Input, CPU is high due to interrupts. In other words,packet are being process-switched. 1.7Mbps of 10Mbps interface is not aproblem if they are fast-switched or CEF switched. Check packet ratealso. Small packets make router very unhappy.Try "show ip interface " to see if you are runningfast-switching or cef-switching. There should not be "no iproute-cahce" in interface config.If you are already running fast-switching, try enabling CEF switching."ip cef" in glabal command will enable CEF.If CPU is still high with CEF, things get hairy. Things like a long ACLon interface, policy routing, packets TTL gets to 0 .. they are allprocess switched. help.Let me know if you find a smoking gun.

High CPU utilization on C3700 ???

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