CDP Network Discovery for Weathermap

[aldino]

Hello,

I mostly use cacti for network trafic graphing.
We have more than a hundred network equipments and topology is frequently modified.
Manually updating network weathermap is *very* boring.

Cisco equipments use a protocol to discover each other : Cisco Discovery Protocol.
Each equipment keeps a table of its neighbors and you can request this table through SNMP.
A rapid scan of these MIBs allows you then to discover network topology.

My idea is to code a plugin that would perform several actions :
-scan CDP MIB to discover network topology from a seed device.
-create discovered devices in cacti.
-create data sources and graphs for trunk interfaces (links between network equipments).
-export topology to Howie's great Weathermap
(http://www.network-weathermap.com/).

Now for the implementation :
-CDP discovery is easy, even with PHP. I found a class for this (not tested yet)
http://www.potato-people.com/code/docs/snmp-cdp/_snmp-cdp.class---snmp-cdp.class.php.html
-Export to weathermap is easy (text file configuration), the only problem is to provide equipments coordinates but I think Howie is working on automatic layout based on graphviz (neato) .
-The hard point I cannot solve is automatic creation of devices and graphs.
I took a look at cacti API and did not see any function for this.

Any idea ?
Does someone already work on this ?

Some other appz already do network discovery (Nedi, netdisco) but not real time graphing.
I really think this feature would be very useful for many people !
Thanks to you all.

[Howie]

It was actually something else I was playing with, not graphviz, but it was the same kind of idea. I got as far as being able to feed a list of adjacencies (as a text file) into my script, and sometimes it would produce an OK looking map. I think it needs more hints about how to lay things out, somehow. I want to get back to it sometime. Probably the answer is to use formatting SNMP Location strings, like NeDi does, to provide a clue on how close devices should be on the map.

I would think that making sure you don't unecessarily delete device and re-add them into cacti would be quite important too. It would be annoying if you had a device in there, removed it, then reconnected it somewhere else only to lose all it's history. Then again, if it was re-purposed for some completely different use, I guess you'd want to lose that info, but I suppose you'd also change it's hostname etc.

You might also want to look at LLDP, so that people with non-Cisco kit can play too (we do exist!).

There is a long-running thread in the Feature Requests about bulk-adding hosts, by the way.