Unlike Delivery and Experience monitoring, which initiate tests, Usage monitoring involves passively monitoring traffic as it passes through a point in the network. This means that the monitoring point must be connected to a destination mirror port (SPAN port) on a switch (in order to view the traffic on the source mirror port) or it must pass traffic from one monitoring point port to another (through bypass ports). We refer to these two methods as “out-of-band” and “inline” respectively. In either case, you typically want to monitor traffic at an aggregation point in the network. For example, the upstream side of an Internet gateway. See Positioning your monitoring point for more information on where to deploy your monitoring point for Usage monitoring.
The out-of-band method involves configuring port mirroring on your switch. The switch’s source mirror port is the one being monitored (typically the aggregation point). The switch’s destination mirror port is connected to the input mirror port on the monitoring point. The following diagrams show how to cable the input mirror port on various monitoring point models for out-of-band Usage monitoring:
The inline method involves using the monitoring point’s fail-to-wire bypass ports (bridge ports) to connect the monitoring point inline with the switch port being monitored (typically the aggregation point). The following diagrams show how to cable the bypass ports on various monitoring point models for inline Usage monitoring: