What are the first steps when troubleshooting High CPU Utilization on Cisco Routers ?

1              Check for a possible security issue. Commonly, high CPU utilization is caused by a security issue, such as a worm or virus operating in your network.

2              Make sure all debugging commands in your router are turned off by issuing the undebug all or no debug all commands.

3              Collect as much as information you can by using show commands if you are able to issue show commands

4              Is the router inaccessible? Can you reproduce this problem? If yes, power-cycle the router and, before reproducing the problem, configure the scheduler interval500 command. This schedules low priority processes to run every500 milliseconds, which provides time for you to run some commands, even if CPU usage is at100 percent. On Cisco7200 and Cisco7500 Series Routers, use the scheduler allocate command.

5              Does the router show symptoms of high CPU utilization at brief and unpredictable intervals? If yes, periodically collect the output of the show processes cpu command, which shows if the high CPU utilization is caused by interrupts or by a certain process

For more informaton please check the source http://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/15095-highcpu.html

Hi,

1)      As Mr. Saqib defines first of all stop all debug and observe the CPU utilization now.

2)      Also check rout is any type of route change in the network? Like you configured OSPF in the network and OSPF route if flapping.

3)      Sometime Telenet or SSH session also increase the CPU utilization.

We faced the same issue on one of our client network and find that the Debug was on for all the switches and routers. After stopping debug on all routers and switches the CPU utilization was reduce70%.

Hope above answer will be usable for you.

Mandats:

1. How many processes are running over the router and how many are desired for the production?

2. You will have to shut down the processes which are not needed. For Eg. maybe in the past you've used any routing protocols which are not in use currently as you may have switched to any other routing protocols. This will be assisting you to reduce your CPU utilization.

3. Also, you should shut down any debugging if running currently.

I hope you'll find this useful.

Thanks.

Issue the command show processes cpu history

when you go from such problem that might be the over load of network user and heavy traffic. for that you need to restart the router so that resources that  a process is kept free and table got empty and other thing is

you can give explicitly this is on the cisco7200 to7500 router

configure terminalscheduler interval500

configure terminalscheduler allocateThe scheduler allocate command guarantees CPU

from this you itself made procesor  to give time to process within time