OpenView Network Node Manager: Designing and Implementing an Enterprise Solution

Network Topology Autolayout Errors

NNM will occasionally draw part of a network topology that varies with what you know is correct. This is NNM’s way of telling you that it is having some sort of difficulty and is making the best of a bad situation. NNM is very conservative. It tends to make few assumptions and will retain old data that once was accurate over new data that is inconsistent or inconclusive. Usually, this is not a bug with NNM, and by exploring the circumstances surrounding the discovery and layout problems, the reason is almost always found. The remedy may not be as apparent.

Sometimes NNM doesn’t lay out part of the network properly because it cannot get the information it needs from a buggy SNMP agent. For example, an Ethernet ...