Designing and Managing Behavior Models - Configuring SNMP Settings for Nodes - Classifying the SNMP Version Configured on Nodes -
Changing the Authentication Protocol for an SNMP v3 Node How NerveCenter Classifies a Node's SNMP Version

Classifying the SNMP Version Configured on Nodes

A node must have SNMP version information before NerveCenter can poll the node or process a trap from the node. NerveCenter enables you to obtain the SNMP version for a node and classify the node with that version. This is required when you don't know the SNMP version for a node or when NerveCenter receives its nodes from Hewlett Packard OpenView Network Node Manager. When NerveCenter receives nodes from OpenView, NerveCenter deems the SNMP version for these nodes to be version 1.

A node must already exist in the database before it can be classified. To classify a node as SNMP v3, the agent must have an initial user configured for discovery. For details, refer to Administrator help or Managing NerveCenter.

For a detailed study of classification, refer to the white paper NerveCenter: Node Classification.

There are three ways in which NerveCenter classifies nodes:

Enable auto-classification of nodes. If auto-classification is enabled, when NerveCenter adds nodes to its database (discovered from a trap, added from OpenView, or imported from another NerveCenter), any nodes without version information are classified at the highest possible level up to the maximum version specified in NerveCenter Administrator. NerveCenter does not attempt auto-classification for nodes that you add manually in Client.
For details, refer to Managing NerveCenter.
Manually classify SNMP version for one or more nodes. NerveCenter attempts to classify one or more nodes at the highest level up to the maximum version specified in NerveCenter Administrator.
For details, see Classifying the SNMP Version for One or More Nodes Manually.
Manually classify all nodes in the Client's Node List. NerveCenter attempts to classify all nodes in its database at the highest level up to the maximum version specified in NerveCenter Administrator.
For details, see Classifying the SNMP Version for All Nodes Manually.

Classification of a node is temporarily disabled when you or someone else performs an SNMP v3 key change operation on the node. The authentication and privacy keys are changed from NerveCenter Administrator.

If NerveCenter classifies a node as SNMP v3, NerveCenter assigns a default security level for communicating with the node. The default security level is NoAuthNoPriv. For details about changing the security level, see Changing the Security Level of an SNMP v3 Node.

If NerveCenter classifies a node as "Unknown", any existing version information for the node is lost during classification. For example, if the node was previously identified as SNMP v3 and is now changed (to v1, v2c, or Unknown), then the v3 related security information for the node is lost.

If NerveCenter fails to classify the node, then the version of the node is set to "Unknown." NerveCenter does not poll nodes or process traps from nodes whose SNMP version is Unknown.

For more information about classification, see also:

Classifying the SNMP Version for One or More Nodes Manually

Follow the procedure below to classify the SNMP version for one or more nodes manually. When using this method, NerveCenter attempts to classify the selected nodes at the highest level up to the maximum version specified in NerveCenter Administrator.

To change the authentication protocol used by NerveCenter to manage an SNMP v3 node:

From the client's Admin menu, select Node List.
The Node List window is displayed.
In the Node List window, select New if defining a new node, or select the node and then Open to change an existing node.
The Node Definition window appears.
Right-click the node or nodes you want to classify and select Classify.
NerveCenter attempts to classify the SNMP version on the nodes up to the highest level specified in NerveCenter Administrator.

Classifying the SNMP Version for All Nodes Manually

NerveCenter Client allows you to classify the SNMP version for all nodes in its node list. With this method, NerveCenter attempts to classify nodes at the highest level up to the maximum version specified in NerveCenter Administrator.

To classify nodes manually:

From the client's Admin menu, select Classify All Nodes.

NerveCenter attempts to classify the SNMP version on all nodes up to the highest level specified in NerveCenter Administrator.

Confirming the SNMP Version for a Node

You can verify the SNMP version that NerveCenter has configured for any particular node. This is useful when manually defining a node to be added to the node list.

With this option, NerveCenter attempts to poll the node using the version specified for the node. The maximum classified version configured in NerveCenter Administrator has no effect on this method of classification. For example, say the maximum classification value set in NerveCenter Administrator is v2c and you have set the version for a particular node to SNMP v3. You can still confirm SNMP v3 communication with the node using the method described below.

To confirm a node's SNMP:

From the client's Admin menu, select Node List.
The Node List window is displayed.
In the Node List window, select New if defining a new node, or select the node and then Open to change an existing node.
The Node Definition window appears.
Select the SNMP tab.
Select the Test Version button.

NerveCenter attempts to communicate with the node using the SNMP version specified in the SNMP Version field.

When NerveCenter Classifies a Node's SNMP Version

There are two main ways that NerveCenter classifies nodes:

On demand -- You can issue a classify command in NerveCenter Client to classify one, several, or all nodes in the database.
Automatically -- You can set up auto-classification in NerveCenter Administrator. Then, when NerveCenter adds nodes to its database (discovered from a trap, added from a platform such as OpenView Network Node Manager, or imported from another NerveCenter), any nodes without version information are classified at the highest possible level. NerveCenter does not attempt auto-classification for nodes that you add manually in Client. Refer to the book Managing NerveCenter for details about auto-classification.

When you enable auto-classification, NerveCenter attempts auto-classification in the following instances:

A node is added through a node file either from importutil or from the Client, and the node does not have a version or has the version "Unknown." This would happen, for example, if you were importing the node from a previous version of NerveCenter.
A node is imported from another NerveCenter Server, and the node does not have a version or has the version "Unknown."
A node is added from a trap, and the node's version is not v3. NerveCenter needs to verify whether these nodes are v1 or v2. If the trap indicates v3, NerveCenter does not need any further verification.
NerveCenter is co-resident with network management platform and the platform sends nodes to NerveCenter. All nodes added from OpenView Network Node Manager are v1 by default.

Disabling auto-classification in Administrator prevents auto-classification for all these cases. If you choose to disable auto-classification, bear in mind that NerveCenter does not poll nodes whose SNMP version is unknown. (You can still classify nodes manually in NerveCenter Client using the available commands.)

Changing the Authentication Protocol for an SNMP v3 Node	How NerveCenter Classifies a Node's SNMP Version
	29 July 2003