SNMP traps on router

CheesyBread

Does anybody know of an SNMP trap command that tracks link utilization? I looked over the Cisco.com netmgmt docs and didn't see anything : Cisco IOS Network Management Command Reference - snmp-server enable traps through snmp-server enable traps ospf cisco-specific retransmit  [Support] - Cisco Systems

I've been looking for a way to provide some kind of alarming or SNMP trap once a link or interface reaches a certain percentage of its configured bandwidth.

Any ideas folks?

Thanks,
-Cheesy

unclerico

If you have an existing NMS most of them will have threshold monitors or the ability to create them. You could always look at RMON as well as it gives you the ability to send an SNMP trap for utilization.

Eildor

CheesyBread wrote: »

Does anybody know of an SNMP trap command that tracks link utilization? I looked over the Cisco.com netmgmt docs and didn't see anything : Cisco IOS Network Management Command Reference - snmp-server enable traps through snmp-server enable traps ospf cisco-specific retransmit* [Support] - Cisco Systems

I've been looking for a way to provide some kind of alarming or SNMP trap once a link or interface reaches a certain percentage of its configured bandwidth.

Any ideas folks?

Thanks,
-Cheesy

Is that even possible to implement on a router/switch? I thought you'd have to enable the device for SNMP then configure your SNMP software to handle the rest... but I'm just guessing, I don't know, hopefully someone who does know will be able to enlighten us!

ecbanks

unclerico wrote: »

If you have an existing NMS most of them will have threshold monitors or the ability to create them. You could always look at RMON as well as it gives you the ability to send an SNMP trap for utilization.

What unclerico said. The most straightforward way to go about this is to have your network monitoring station poll the interface, and then send you an alarm once a utilization threshold has been exceeded. Easy to set up, low risk, and customizable...assuming your NMS is halfway decent.

If you need the router/switch to monitor itself and send a trap, in addition to using RMON, you could look at using Cisco Embedded Event Manager. IOW, let EEM monitor an SNMP OID of a specific port, and react to it. I haven't done this myself, but a quick glance at the docs make me think it's very possible.

Another thought is that storm-control can do unicast throttling, and send a trap when the threshold you set is tripped. Not exactly what you're looking for (because storm control actually drops traffic exceeding the threshold), and storm-control is not universally supported across all Cisco hardware, but maybe interesting.

Forsaken_GA

Easiest way to do it is to use EEM to monitor the txload and rxload (depending on whether you want to monitor egress or ingress utlization) variables.

event manager applet UTLIZATION
event interface name FastEthernet 0/0 parameter txload entry-op gt entry-val 204 entry-type value poll-interval 1
action 1.0 snmp-trap strdata "$_interface_name link utlization: $_interface_value / $_interface_parameter"

and then change the load-interval to as low as possible on the interface to get the most realtime statistics as possible.

Basically, this polls the interface for the txload value, which is in the range of 1 to 255. So you have to do some math. If you want it to alert at 80% of load, that would be 204 (which is where the number above comes from). If you wanted it to trap after it reached 75% instead, it'd be 191. As soon as the txload goes above the number you specified, it generates a trap. If you wanted to monitor ingress, just substitute rxload for txload instead.

You'll also need to make sure to enable EEM SNMP traps: snmp-server enable traps event-manager

CheesyBread

This is exactly what I was looking for. I'm going to try to write a change request up and get this put in.