NQA Association Mechanism
The NQA association function creates association entries to monitor the probes in a test instance and to trigger other modules to respond accordingly when the number of probe failures reaches a specified value. Figure 6-21 shows the implementation of the association function.
NQA association involves three modules: application, track, and monitoring function (such as NQA) modules. The track module resides between the application and NQA modules. When there is a change in the status of the monitored item, the NQA module reports this change to the track module. The track module then instructs the application module to process the change accordingly. This process implements the association function.
The following uses a static route as an example.
In this example, there is a static route with next hop 192.168.0.88. Association between the NQA module, track module, and application module determines the validity of the static route in real time. If the NQA module finds that next hop 192.168.0.88 is unreachable, it notifies the static route module through the track module. The static route module then determines whether the static route is invalid.