Unlike Delivery and Experience monitoring, which initiate tests, Usage monitoring involves passively monitoring traffic as it passes through a point in the network. You typically want to monitor traffic at an aggregation point in the network. See Deploying Your Monitoring Point for more information on where to deploy your monitoring point for Usage monitoring.
There are two methods for physically connecting a monitoring point to your network for Usage monitoring: “out-of-band” and “inline”. The out-of-band method uses one port on the monitoring point. The inline method uses two.
The out-of-band method requires that your switch is capable of port mirroring. The switch’s source mirror port is the one being monitored (typically the aggregation point). The switch’s destination mirror port is connected to a Usage monitoring port (Out-of-band) on the monitoring point.
The following diagrams show how to cable the primary Usage monitoring port on various monitoring point models for out-of-band Usage monitoring:
The inline method involves using a pair of “bypass” ports (Usage monitoring ports (Inline)) to connect the monitoring point inline with the switch port being monitored (typically the aggregation point). The “uplink” port of the pair is connected towards the Internet. The “downlink” port of the pair is connected to the switch. Traffic flows through the monitoring point from one of the bypass ports to the other. Traffic will continue to flow even if the monitoring point loses power.
The following diagrams show how to cable the primary Usage monitoring bypass ports on various monitoring point models for inline Usage monitoring: