Managing NerveCenter - Managing Node Data - Maintaining the Node List -
Populating the Node List Manually Troubleshooting: Managing node data

Maintaining the Node List

To detect and correlate network events, NerveCenter must have basic information about each of the managed nodes it is monitoring.

Once you have initially populated the node list (see Populating the Node List Initially), NerveCenter will need a way to adapt its node list to reflect changes in your network topology. NerveCenter offers several methods for adding and deleting nodes.

These methods include:

The following chart illustrates how each method affects NerveCenter's node list.

Maintaining NerveCenter's Node List

Method	Adds Nodes	Deletes Nodes	Changes Node Data
Resync with the platform
Discover nodes from traps
IPSweep behavior model
Manual additions, deletions, and changes

Synchronization with your network management platform

Over time, a network's topology will change. Eventually your network management platform will add newly discovered devices to its database. It will also delete nodes and change node information. If NerveCenter depends on your network management platform for the data in its node list, it will need to adapt to reflect these changes.

NerveCenter will automatically update its node list to keep in sync with your network management platform's node data. This occurs in the following situations:

When your network management platform adds a node to its node database. After NerveCenter verifies the node meets the criteria set by its filters, it will add the node to its node list.
When your network management platform deletes a node from its node database. NerveCenter will delete from its node list any node that is set to Autodelete. Autodelete is the default setting for any new node added to the node list. This setting can be changed in the node's Node Definition Window in the NerveCenter Client. (See the section "Discovering and defining nodes" in Designing and Managing Behavior Models.)
When your network management platform changes information about a node in its node database. NerveCenter will make any necessary changes to its node data, including changes in the community string, address, parenting information or the managed/unmanaged state.

Most often, the node list will only be updated a node at a time. Occasionally, NerveCenter will need to perform a complete resynchronization with the platform. A resynchronization gathers from the platform the most current node data for all nodes. This occurs in the following situations:

The NerveCenter Server is started and successfully connects to the OpenView Platform Adapter (OVPA).
A connection between the NerveCenter Server and the node source successfully reconnects after being broken.
The NerveCenter administrator changes the way in which NerveCenter filters by capabilities or system Object Identifiers (OIDs).
A user manually chooses Resync in the Server menu of the NerveCenter Client.

The Machine Name field on the Node Source tab of the NerveCenter Administrator specifies the name of the host running the platform resynchronizing with NerveCenter. (See Populating NerveCenter's node list using your network management platform as a node data source for more details on how to declare a node data source.)

The Node Source and IP Filters tabs also specify the parameters NerveCenter uses to filter node data. (See Filtering Nodes.)

Anyone administering NerveCenter should be aware of two important scenarios involving changes to your network management platform's database:

If the name changes in your network management platform's database, NerveCenter considers it to be a new node.
If a node is unmanaged in one of your network management platform's maps but is managed in another, the node will remain in the managed state in NerveCenter's node data.

Adding Nodes Discovered from Traps

NerveCenter occasionally receives traps from nodes not included in its node list. In this situation, NerveCenter must make two decisions:

Whether to process the trap or ignore it. (See the section Processing Traps from Unknown Nodes)
Whether to add the unknown node to its node list. This section explains how to configure this setting.

To configure the way unknown nodes affect NerveCenter's node list:

Open NerveCenter Administrator and connect to the appropriate Server.
See Connecting Administrator to a NerveCenter Server on page 38.
Select the Server tab.
NerveCenter displays the Server tab.
In the Discover Nodes from Traps list, select which nodes NerveCenter should place in its node list:
- With a None setting, NerveCenter will not add any unknown nodes to the node list.
- With a Filter setting, NerveCenter will add to its node list an unknown node sending a trap only if it meets the criteria established by the node filters.
- With an All setting, NerveCenter adds to its node list any unknown node sending a trap, regardless of the node filters.
Select Save.

Any time NerveCenter receives a trap from a node not listed in its node list, NerveCenter handles the node according to the criteria you set in the Discover Nodes from Traps list box.

Adding and Deleting Nodes Manually

Occasionally, you may want to monitor one or more nodes that do not match the parameters set by the node filters. Or you may want to delete a node or a group of nodes. NerveCenter gives you the ability to alter the node list to your own specifications.

When maintaining the node list manually, you have the following options:

Adding a Node Manually -- You add nodes in the NerveCenter Client module. To learn how to add a node manually, refer to the instructions in Designing and Managing Behavior Models.
Deleting a Node Manually -- You delete nodes in the NerveCenter Client module. To learn how to delete a node manually, refer to the instructions in Designing and Managing Behavior Models.
Filter Out a Node That was Manually Deleted -- If you do not complete this step, the nodes you delete manually will be added the next time a resynchronization occurs between NerveCenter and the network management platform's database or the next time the IPSweep behavior model runs the ipsweep script. Following are instructions for filtering out a node.

To filter out a node that was manually deleted:

Open the NerveCenter Administrator and connect to the appropriate NerveCenter Server. See Connecting Administrator to a NerveCenter Server on page 38.
From the Admin menu, choose IP Filters.
The IP Filters tab is displayed.
From the IP Address Filters list, select the subnet address that contains the node or nodes you wish to be permanently deleted.
In the Exclusion List field, enter all the nodes you want permanently deleted from the node list. To exclude more than one node, separate each number with a comma without a space. To exclude a continuous range of nodes, use a hyphen to separate the minimum and maximum number.
Select Update.
Select Save.

The nodes are permanently deleted from NerveCenter's database.

Populating the Node List Manually	Troubleshooting: Managing node data
	29 July 2003