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SNMP CPU Usage

Posted: Tue Aug 01, 2017 11:23 am
by grspotter
What OID should be used to get the CPU Usage like in the stats page of the switch?

I feel like the answer is simple. I'm not a noob, but it has baffled me for most of the day. Thanks.

Re: SNMP CPU Usage

Posted: Tue Aug 01, 2017 12:53 pm
by Eric Stern
You can't get that number directly from SNMP, but you can get something close by adding ssCpuSystem and ssCpuUser together. Or start with 100 and subtract ssCpuIdle.

Re: SNMP CPU Usage

Posted: Tue Aug 01, 2017 1:07 pm
by grspotter
Thank you for the response. I will see if I can implement that in my NMS. I was hoping it wasn't something too obvious that I was missing.

Re: SNMP CPU Usage

Posted: Tue Aug 01, 2017 1:08 pm
by sirhc
grspotter wrote:Thank you for the response. I will see if I can implement that in my NMS. I was hoping it wasn't something too obvious that I was missing.


You do realize that the CPU useage has nothing to do with the switch's capacity or load?

The embedded CPU is only to run the UI/CLI and some daemons and has nothing to do with switching capacity or load.

Re: SNMP CPU Usage

Posted: Tue Aug 01, 2017 1:21 pm
by grspotter
Wow! Thanks again. I did not realize that and it's exactly what I was wanting to monitor. Is there a way to get that info?

Re: SNMP CPU Usage

Posted: Tue Aug 01, 2017 1:44 pm
by sirhc
grspotter wrote:Wow! Thanks again. I did not realize that and it's exactly what I was wanting to monitor. Is there a way to get that info?


The switch like most switches uses a "switch core" the switch core handles all packet forwarding and most all if not all switch cores are designed to handle full line speed on all ports at the same time.

This is stated on our and most other manufacturers spec sheet as non-blocking line speed. Switch cores do not use a single CPU but rather MANY little dedicated CPU's. A single CPU switch would be what is called a "soft switch" which is more like turning a linux box with many ports into a switch with software.


The switch core code is all built into the switch core and we do not mess with that.