124Configuring trackTrack overviewIntroduction to collaborationThe track module works between application and detection modules, as shown in Figure 28. It shields thedifferences between various detection modules from application modules.Collaboration is enabled after you associate the track module with a detection module and anapplication module. The detection module probes specific objects such as interface status, link status,network reachability, and network performance, and informs the track module of detection results. Thetrack module sends the detection results to the associated application module. When notified of changesof the tracked object, the application modules can react to avoid communication interruption andnetwork performance degradation.Figure 28 Collaboration through the track moduleCollaboration fundamentalsThe track module collaborates with detection modules and application modules:• Collaboration between the track module and a detection module• Collaboration between the track module and an application moduleCollaboration between the track module and a detection moduleThe detection module sends the detection result of the associated tracked object to the track module.Depending on the result, the track module changes the status of the track entry:• If the tracked object functions normally, for example, the target interface is up or the target networkis reachable, the state of the track entry is Positive.• If the tracked object functions abnormally, for example, the target interface is down or the targetnetwork is unreachable, the state of the track entry is Negative.• If the detection result is not valid, for example, the NQA test group that is associated with the trackentry does not exist, the state of the track entry is Invalid.The following detection modules can be associated with the track module:
