High CPU consumption on router C1841-ENTBASEK9-M

[Jose Zapata (AMAGI)]

Good day

Currently I present the following problem: I have a cisco 1841 router with firmware version: 12.4 (24) T3, which has a high consumption of its CPU, it works as an edge to receive an Internet link and it is affected by the behavior of the computer. I perform a show processes cpu sorted | exclude 0.00 and I get:

show snmp stats oid

show logs

I would like your support to see how I can delete these OID, I would not like to remove the SNMP SERVER since I lose the management and monitoring of the equipment.

Attentive to your comments

[Joseph W. Doherty]

I don't know if you can remove the OID from the router. How often does your SNMP management station poll?

[Jose Zapata (AMAGI)]

How can I check the frequency you tell me?

[Leo Laohoo]

1. Kill SNMP first and see if CPU drops down.
2. Router is running a "T" train. My recommendation is to upgrade to a more stable "M" train.

[Jose Zapata (AMAGI)]

1.- Yes, I have disabled in the CSMP service of the router and the CPU consumption drastically decreases, however, I would not like to apply this solution because I lose the monitoring of the equipment.

2.- Yes, I will update the firmware of the equipment, however, I wanted to know if there is a command or action to suppress this behavior.

[Giuseppe Larosa]

Hello Jose,

an SNMP view could limit what OIDs can be polled but you should know what MIBs are causing the load.

Your device is not supporting a BGP full table otherwise polling the IP routing table would be a good candidate.

On other hand the log message about SNMP input queue full matches some SW bugs I have found on switches like C3650 or C3850.

You could try to remove the SNMP configuration for one hour and then re-configure it as a way to restart the SNMP process as suggested by Leo,

In any case an IOS upgrade may be recommended on the long term.

Hope to help

Giuseppe

[Jose Zapata (AMAGI)]

Thank you

I will proceed to implement your recommendations.

In this case, how can I poll the OID?

[Giuseppe Larosa]

Hello Jose,

to perform an SNMP get you need a MIB browser.

If you have access to your network management server you can use it to make the SNMP queries.

In order to find out the OIDs you can use the Cisco tool that was once called SNMP navigator

new link is the following

https://snmp.cloudapps.cisco.com/Support/SNMP/do/BrowseOID.do?local=en

you can use the option called Browse the object tree.

for configuring SNMP views see

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/snmp/configuration/12-4t/snmp-12-4t-book/nm-snmp-cfg-snmp-support.html

go to the section named " Creating or modifying an SNMP view record"

Hope to help

Giuseppe