Re: ifIndex

[Mel Beckman <mel () beckman org>]

Cisco has a feature you can enable called “Interface Index Persistence”:

https://www.cisco.com/c/en/us/support/docs/ip/simple-network-management-protocol-snmp/28420-ifIndex-Persistence.html

This solves the problem, at least with Cisco gear.

 -mel beckman

On Oct 12, 2018, at 1:33 PM, Naslund, Steve <SNaslund () medline com<mailto:SNaslund () medline com>> wrote:

I see this all the time.  Especially in module chassis.  It seems like sometimes it has to do with when each board goes 
to a ready state as the system boots.  We also see renumbering due to virtual interface and board additions.  While you 
are running they seem to get the next ifindex available but when you reboot the seem to be in the order they come up or 
the order they are in the configuration.  It is a real pain and some software allows us to rescan a device and other 
software we have no easy way other than to delete and the re-add the device.  I feel your pain on this one.

I have no idea why most NMS systems can't seem to understand this and just rescan at a set interval or after an up/down 
device event.

Steven Naslund
Chicago IL

do folk have experience with platforms where ifIndexes are not stable
across reboots etc?  how do you deal with it?  do some of those
platforms trap on change?