Interface overrun errors, however there is no interface load nor high cpu usage on router

[sheldonpe]

Hi,

I have just received high interface overrrun errors on one of the routers I manage at work. On checking the cisco site, I find  that these errors could occur because the interface's capability has been exceeded and it cannot process the oncoming traffic, therefore it drops the packet.

However on checking the router I see that there is no interface load at all, nor is there any high cpu utilization on the router. (Its off business hours right now, so there is no one at the office).

#sh processes cpu

CPU utilization for five seconds: 0%/0%; one minute: 2%; five minutes: 4%.

##

reliability 135/255, txload 1/255, rxload 1/255

0 packets input, 0 bytes, 0 no buffer

     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

     3639 input errors, 0 CRC, 0 frame, 3639 overrun, 0 ignored

     0 watchdog, 0 multicast, 0 pause input

     0 input packets with dribble condition detected

It says 3639 errors and 3639 overrun.. However there is no packets input at all! Does that mean that the overrun counter is incrementing even though there is no packets arriving at the interface?? Is this a software bug or is there a real issue at hand?

Thanks!

[Tharak Abraham]

Sheldon,

You may have to check the CPU history, with "sh proce cpu hist".

Do you have a spare interface to terminate the link ?

Wonder why the link is not 100% reliable (reliability 135/255) though

Also can you clear and check if this is frequent ?

[vmiller]

This question has been answered in other threads.

https://supportforums.cisco.com/thread/1003090

From the evidence, I suspect a layer 1 problem.