Network Protocol Manager for IS-IS performs availability-based root-cause analysis of the discovered IS-IS topology objects. It also relates physical-transport problems to the IS-IS objects, along the affected data path, that are no longer accessible or suffer from lack of response or performance as a result of the physical-transport problems.
When Network Protocol Manager for IS-IS detects an IS-IS failure, it checks for any physical-transport problem from IP Availability Manager that might be causing the failure. If it finds such a problem, Network Protocol Manager for IS-IS diagnoses the IS-IS failure as a symptom and exports the underlying physical-transport problem and the IS-IS symptom to the Global Manager, as explained in Chapter 4, “IS-IS Cross-Domain Impact Correlation Analysis.”
If it does not find such a problem, Network Protocol Manager for IS-IS focuses its analysis on just the IS-IS domain and performs the root-cause analysis described in this chapter.