Changing interface numbers on subinterface

[Jorta]

Hello,

I've done some searching, but have not found an answer to this problem. I apologize if it has been discussed to death.

We have a Cisco ATM interface with a number (40+) of subinterfaces that we are tracking. The problem is that when a subinterface changes, the SNMP interface number associated with that subinterface changes in a non-predictable way.

I am wondering if there is a way to automate the changing of the interface values in RRDTool instead of going through the Cacti interface to enter the new interface number for each graph. In Nagios, we are using a perl script to do an snmpwalk and grab the interface numbers as they change - does anyone have a way to do this with Cacti?

Thanks,

[raX]

There is a way to make this less painful in Cacti, although it isn't completely automated yet. When you create your graphs, you will be presented with a screen prompts you for an "Index Type". Instead of leaving it as "ifIndex", you should change it to something that does not change between reboots (ifName, ifAlias?).

Now when the ifIndexes change, you have to go into Cacti -> Devices, select the device in question, and click the "reload data query" icon next to "SNMP - Interface Statistics". Now click "Save" on this edit screen and everything should update correctly.

The next step for Cacti is to detect when the ifIndexes change and do this reload process automatically.

-Ian

[Jorta]

Perfect. Thanks for the response - I'll put that into action and look forward to the next release of Cacti!

[Lux]

rather than redoing everything in Cacti, you may be able to solve your problem directly on the router with the command snmp mib persist. This will force the router to remember the index to interface mapping across reloads.

Mike

[Jorta]

Thanks Lux,

I thought there was something along those lines on the Cisco, but could not find it - but as usual you don't find what you are looking for when you are looking in the wrong spot. I like that idea too and am testing it now.

Thanks!

[bulek]

Actually the right command is "snmp-server ifindex persist".

- Piotr

[Jorta]

Seems to depend on the version of the IOS that you are using. I didn't go so far as to break out the IOS/Command version, but in our lab some older/some newer IOS versions and router models used one or the other command.

Thanks!

[TFC]

Actually the right command is "snmp-server ifindex persist".

- Piotr

This is the perfect solution but, unfortunately some IOS versions are not supported snmp-server ifindex persist command. For example My 7507 has 12.1 and there is no command about persistence.
I just said for information

[BitFlipper]

I have an environment that is pretty well described here. The source initiative can be found at my original post and remains unsolved. I am trying to monitor VPN session statisitcs on a Cisco Concentrator. Sessions come and go, indexes change but session 'names' are constant. Ian pointed out that you can 'refresh' your indexes manually but this won't work very well when the indexes are constantly changing.

Is there something that I am missing or is this a feature that hasn't been implimented as yet?

Thanks in advance.

[TheWitness]

BitFlipper,

Are we talking about ATM? Are you talking aboue PVC's? Please let me know.

Thanks,

TheWitness

[BitFlipper]

TheWitness:

My apologies. Not talking about either one. This post addresses the vary issue I am having. The proposed solution here won't necessarily work in my environment (talking about Cisco VPN session statistics).

Did you have a chance to look at my correlating post?
http://www.raxnet.net/board/viewtopic.php?t=4562

Thanks for following-up on this ...