The Session Monitor system works by capturing the traffic from your network, correlating it in real-time, and storing it in indexed formats so that they are available for the various reports offered by the web interface.

The Session Monitor system architecture has three layers:

• Probe layer: This layer is responsible for capturing the traffic from your network and performing the Media Quality analysis. The probes send meta-data for each of the signaling messages to the Mediation Engine layer and analyze the RTP streams locally, sending the results of this analysis to the Mediation Engine layer.
• Mediation Engine layer: This layer is responsible for understanding in real-time the traffic received, correlating it and storing it for future reference. This layer is also responsible for measuring, managing, and storing the KPIs. In the common case, there is one Mediation Engine per geographical site. It is possible, however, to have the probes from multiple geographical sites sending the traffic to a single Mediation Engine. It is also possible to have multiple Mediation Engine installations in the same geographical site.
• Aggregation Engine layer: This layer is responsible for aggregating the global KPIs from all the Mediation Engine linked to it, and for the global search features. In a typical setup, there is only one AE for the whole network.

Each of the three layers supports high-availability by deploying two identical servers in active-passive or active-active modes of operation. For small setups, it is possible to run the probe layer and the Mediation Engine layer on the same physical hardware. The Aggregation Engine layer always requires its own hardware.

From the Session Monitor products perspective, the Operations Monitor and the Control Plane Monitor run on the Mediation Engine while the Mediation Engine Connector and the Fraud Monitor products run on the Aggregation Engine.