4 Replies Latest reply on Oct 17, 2014 10:25 AM by RichardLetts

    Best approaches to discovery?


      I wondered if there are any better approaches to performing network discoveries, especially on large networks, as it simply takes far too long, and discovers devices we simply don't care to monitor.


      We have 2 /24 bit management networks for our L3 devices, but our L2 devices sit on our primary network which is /18 broken down into /24 or smaller subnets, so you can imagine this can take a long time to scan, and also picks up lots of devices we don't care about.  Not all of our devices support snmp so we cant limit to discovering only these devices.  Most of our access switches are on the primary network.  I also don't want to have individual subnet groups, as there would be too many to manage.


      Now, if we could only scan the management network and use CDP to discover connected switches, that would be ideal, but for some reason, CDP isn't offered, although I know SW is multi vendor, and CDP is cisco proprietary, surely it wouldn't be that difficult to provide such a useful feature to aid discovery?


      We could then simply scan 2 /24 bit networks and if we could use CDP, it would discover all uplink devices!.. perfect!


      Just wondered if I may be missing something, or if anyone had adopted any strategies for optimizing discoveries?

        • Re: Best approaches to discovery?

          I wouldnt suggest that I have the best way, but what I did (large network too) is to divide up the network into smaller segments and scan each (on a schedule) on each of the 7 days of the week.  Then I ignore devices that I dont care about so that when it rescans, i dont see them anymore.  If something is added, or changes in the devices that I do care about then I am notified in the next scan. 


          Its a lot of work, and I think that there are lots of changes that need to be made to discovery such as your suggestion or even a better use of filters.  But that is the way I went.  It was a pain for a while but its starting to work for me.



          • Re: Best approaches to discovery?

            bu993r.. was hoping for something a little more elegant!


            The more and more I use SW products, the more annoyances I find with it!  It really can be frustrating sometimes!

            • Re: Best approaches to discovery?

              This is not the answer you are looking for but: don't do them.What do you mean by large? the network I operate has about 15,000 devices in total on it.


              We use our cmdb to populate Orion with the devices. our CMDB is populated from our asset database (finance likes to know where that $120K router card is installed for auditing, so if we buy it we track it.)