Concepts for Discovery

The NNMi default behavior of discovering only routers and switches enables you to focus your network management on the critical or most important devices. In other words, target the backbone of the network first. Generally, you should avoid managing end nodes (for example, personal computers or printers) unless the end node is identified as a critical resource. For example, database and application servers might be considered critical resources.

NNMi provides several ways to control what devices to discover and include in the NNMi topology. Your discovery configuration can be very simple, quite complex, or anywhere in between, depending on how your network is organized and what you want to manage with NNMi.

Each discovered node (physical or virtually hosted) counts toward the license limit, regardless of whether NNMi is actively managing that node. The capacity of your NNMi license might influence your approach to discovery.

When tracking license information, note the following:

• Consumption: NNMi discovers and manages nodes up to the NNMi licensed capacity limit (rounded up):

  • VMwareVMware ESX and VMware ESXi software uses SOAP protocol to implement bare-metal hypervisors. : Each device with a Device Profile of vnwareVM is equivalent to 1/10^th node.

  • All other devices are equivalent to one discovered node.

For details about license limits, see “Track Your NNMi Licenses” in the NNMi Help for Administrators.

• If the number of discovered nodes reaches or exceeds the licensed capacity limit, no new nodes are discovered unless one of the following occurs:

  • Install a license extension.
  • Review your configuration settings and limit NNMi discovery to only the important nodes in your network environment. Then, delete nodes and let NNMi rediscovery reset the managed inventory of nodes.

Status monitoring considerations might also influence your choices. By default, the State Poller only monitors interfaces connected to devices NNMi has discovered. You can override this default for some areas of your network, and you can discover the devices beyond the edge of your responsibility. (For information about the State Poller, see NNMi State Polling.)

NNMi provides two primary discovery configuration models:

• List-based discovery—Explicitly tell NNMi exactly which devices should be added to the database and monitored through a list of seeds.
• Rule-based discovery—Tell NNMi which areas of your network and device types should be added to the database, give NNMi a starting address in each area, and then let NNMi discover the defined devices.

You can use any combination of list-based and rule-based discovery to configure what NNMi should discover. Initial discovery adds these devices to the NNMi topology, and then spiral discovery routinely rediscovers the network to ensure that the topology remains current.