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?