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How to monitor bandwidth on Catalyst via SNMP?

I've got c3750g with 12.2(55)SE.

When I try ifSpeed (, i've got 1 peak 999999999 and then only 0. Polling is 1 second.

When I try ifHighSpeed (, I've 0 also.

When I try ifInOctets from snmp-v2 MIB (, I've got results, but since it summary - my software cannot do calculations and I cant get instant interface bandwidth.

Is there any solutions for catalyst?

Cisco Employee

Re: How to monitor bandwidth on Catalyst via SNMP?


Are you saying ifSpeed. is changing value from one poll to the next? What kind of interface is it? Sounds like a bug, or an error in polling. Please post the snmpwalk of ifDescr, ifType, and ifSpeed.

For the ifHighSpeed issue, from the IF-MIB entry about that object: "For a sub-layer which has no concept of                bandwidth, this object should be zero." Are you polling ifHighSpeed on a sub-layer interface?

Bandwidth utilization is always calculated by taking multiple readings of in or out counters. There will not be a separate counter kept in our snmp agent, when separate values already exist and can be calculated. Thus, since you can use ifSpeed and poll ifInOctets to get the delta, and then calculate the result, our snmp agent will not contain the utilization number.

If you want a graph of bandwidth utilization over time, I would suggest obtaining MRTG. It is available free of charge over the web, just search for MRTG download.

Hope that helps,


New Member

Re: How to monitor bandwidth on Catalyst via SNMP?


Thanks for reply. I've already figured out, that I have to do calculations based on ifInOctets. Originally I thought that it's possible to get something like 5min average speed in show int.

I'll try to look into my application (WhatsUP Gold v.11) to find out, if its possible to perform calculations inside it. Don't want to install MRTG just because of 3-4 items to loot to.

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