There is some confusion between 'Time TO Threshold' and 'time OVER threshold'
For Time OVER Threshold, alarm_enrichment is required in addition to ppm, baseline_engine, and prediction_engine.
If the user starts the ppm probe, and alarm_enrichment is installed on the same hub, alarm_enrichment is now required, even if you didn?t configure Time over Threshold. Therefore, alarm_enrichment should ONLY be installed along with ppm if the intent is to configure the optional 'Time over Threshold.'
For time-TO-threshold there is no alarm_enrichment requirement.
1. You can deploy baseline_engine and prediction_engine in advance and then deploy alarm_enrichment as needed to those hubs for which you require Time Over Threshold functionality
2. The alarms generated from the secondary NAS must be passed to the primary NAS using replication. The following article on the CA UIM Probe Wiki contains more information: