RSPAN enables consolidation of network monitoring at a single location. It works by mirroring target traffic from multiple source ports into a particular VLAN dedicated for monitoring purposes.
The analyzer is connected on the destination switch to the RSPAN VLAN. When this VLAN is trunked to other switches, you can then transport the RSPAN traffic across multiple switches in your network.
You use the monitor session command to enable a RSPAN session. With this command, you can set the packet source, the packet destination (using the rspan-vlan key of this command), and the packet direction (egress, ingress, or both).