Is there a common way to obtain information about neighboring devices from a cisco switch, provided that we're using SNMP, and CDP is completely off?

I may be on a totally wrong track here, so I could probably rephrase — on a larger scale, what's the proper way(tm) to automate the topology discovery and monitoring for a cisco-based L2 network?

Thanks in advance!


Turning off CDP is generally meant to stop topology discovery. If you're running SNMP and know the credentials, a sweep of known subnets on the network can provide you a list of switches/routers.

Beyond that, you're going to have to get your hands really dirty by recording MAC addresses and trying to figure out the topology from the forwarding tables. Spanning tree might also provide clues here.

  • thanks for your reply! CDP is turned off for "security reasons" by the network operator (I'm merely a contractor for monitoring system), but they're using some UDLD. I'm not familiar with the latter really, and it doesn't seem to have any "get" oids, hence my question. – etranger May 19 '11 at 12:56
  • @etranger in that case, show udld <interface> would work too, though I'm relatively certain that there aren't any OIDs for it. Looks like this one will have to be manual, if you can't convince them to enable CDP for just a few minutes :-/ – Hyppy May 19 '11 at 12:58
  • that's weird, the protocol is there, but there's no related snmp data, do you have any thoughts as to why? CDP is currently not an option, because the policy requires it to be off, and the monitoring has to be quite regular (we'll be polling the devices at least once a day). – etranger May 19 '11 at 13:02
  • @etranger No idea. There may be another way around this, but I don't know what it is. – Hyppy May 19 '11 at 13:37

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.