[mrtg] OIDs changing.

[Dan]

gaurav wrote:
> Recently I was amazed to see few things in the devices I was using MRTG for.
> 
> First, I have two cisco uBR 7200 with same IOS version and same model 
> but the OIDs in them for same datas to are to be retrieved are different 
> in the leaf OIDs whereas the branch OID is the same.
> 
> i mean if 1.3.2.1.2.1.2.3.1.2.1.2 was for one than 
> 1.3.2.1.2.1.2.3.1.2.1.9 was for the other..
> 
> Second thing is one of the device got automatically rebooted because of 
> some power failure lately, and i was unable to see MRTG graphs for few 
> of the datas polled. Upon further diagnose i found that the leaf OIDs 
> have increased with two
> 
> i mean if 1.3.2.1.2.1.2.3.1.2.1.2 was the OID that was polled than after 
> the reboot it wasnt existing and  1.3.2.1.2.1.2.3.1.2.1.4 was the one 
> that was providing the necessary values.
> 
> Has any one came across this type of situations before...please do share..
> 
> Does the OIDs get changed so abnormally or is it because of some faults 
> in the device.

You'll need to add the following config to your cisco routers:

snmp-server ifindex persist

and this will stop the interfaces from changing OID's.

See 
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/122sx/swcg/ifindx.htm 
for more info.

Dan.