OpenView Network Node Manager: Designing and Implementing an Enterprise Solution

DHCP Reassigns an IP address

Suppose you remove an Ethernet switch from service and return its IP address manually to the DHCP lease pool. As NNM performs a status poll every five minutes, this switch will appear to go down. Meanwhile, you install a replacement switch with a different legitimate IP address. You manually ping it and NNM discovers it, adds it to the map, and shows the new network connections. Suddenly, a non-SNMP capable device comes online, issues a DHCP request, and receives the recycled switch’s IP address. NNM’s next five minute status poll succeeds and the old switch (seemingly) goes back up! But NNM is no longer able to communicate with the old switch SNMP agent, and leaves the switch icon and its connection on the map, ...