D.5 What does NNMi analyze?
Using SNMP, NNMi utilizes SNMP agents (processes running on managed nodes that provide management functions) to acquire information from managed nodes. The SNMP agents manage the interfaces and ports on the managed nodes, and can associate them with one or more nodes.
The following list shows the status categories that can be associated with SNMP agents:
Unknown - Not applicable
Disabled - Not applicable
Critical - Indicates the SNMP agent does not respond to SNMP queries.
Minor - Not applicable
Warning - Not applicable
Normal - Indicates the SNMP agent responds to SNMP queries.
No Status - Indicates the SNMP agent is not polled.
An IPv4 address is a routable address that responds to ICMP. An IPv4 address is normally associated with a node. NNMi reports the status of a node as follows:
Unknown - Not applicable
Disabled - Indicates the interface associated with this IPv4 address cannot be managed or is disabled.
Critical - Indicates the IPv4 address does not respond to ICMP queries (pings the device).
Minor - Not applicable
Warning - Not applicable
Normal - Indicates the IPv4 address responds to ICMP queries.
No Status - Indicates the IPv4 address is not polled.
An interface is a physical port that can be used to connect a node to the network. NNMi reports the status of an interface as follows:
Unknown - The SNMP agent associated with the interface does not respond to SNMP queries. The NmsApa service cannot determine the health because the ifAdminStatus and ifOperStatus values cannot be measured.
Disabled - Indicates the interface is administratively down (ifAdminStatus=down).
Critical - Indicates the interface is operationally down (ifOperStatus=down).
Minor - Not applicable
Warning - Not applicable
Normal - Indicates the interface is operationally up (ifOperStatus=up).
No Status - Indicates the interface is not polled.
A node is a device that NNMi finds as a result of the spiral discovery process. A node can contain interfaces, boards, and ports. You can separate nodes into the following two categories:
Network nodes, which are active devices such as switches, routers, bridges, and hubs
End nodes, such as Linux or Windows servers
NNMi typically manages network nodes, reporting node status as follows:
Unknown - The SNMP agent associated with the node does not respond to SNMP queries and the polled IPv4 address does not respond to the ICMP query. This indicates that NNMi is unable to manage the node.
Disabled - Not applicable
Critical - Indicates any one of the following:
- The node is down as determined by neighbor analysis.
- The node is marked as important and is unmanageable (NNMi cannot access the node from the NNMi server).
- The node is an island (if it has no neighbor), and therefore is unmanageable.
- The NmsApa service cannot determine whether the node is down or the incoming connection is down.
Minor - Indicates any one of the following:
- The SNMP agent associated with the node does not respond to SNMP queries.
- At least one interface in the node is down.
- At least one IPv4 address on the node does not respond to ICMP.
Warning - Not applicable
Normal - Indicates the SNMP agent of the node, polled interfaces, and polled IPv4 addresses are up.
No Status - Indicates the SNMP agent, all interfaces, and all IPv4 addresses of the node are not polled.
Connections are Layer 2 physical connections and Layer 3 network connections. NNMi discovers connection information by reading forwarding database (FDB) tables from other network devices and by using devices that support discovery protocols, such as Cisco Discovery Protocol (CDP) and Extreme Discovery Protocol (EDP). NNMi reports the status of a connection as follows:
Unknown - Indicates all endpoints of the connection have Unknown status.
Disabled - Indicates one endpoint of the connection is disabled.
Critical - Indicates all endpoints are operationally down.
Minor - Indicates one endpoint is down.
Warning - Indicates endpoints have unknown and non-critical status.
Normal - Indicates all endpoints are operationally up.
No Status - Indicates one endpoint is not polled.
A node group is a logical collection of nodes created by an NNMi administrator to customize the polling configuration. For example, some nodes, such as routers, might be critical to a business and therefore must be polled more frequently. For such a case, the NNMi administrator would define a node group containing the critical routers and configure them for a shorter polling cycle.
NNMi reports the status of a node group as follows:
Unknown - Indicates all nodes in the group have Unknown status.
Disabled - Not applicable
Critical - Indicates all nodes in the group have Critical status.
Minor - Indicates at least one node in the group has Critical status.
Warning - Indicates nodes have unknown and non-critical status.
Normal - Indicates all nodes in the group have Normal status.
No Status - Indicates all nodes in the group have no status.