Port mirror, also known as SPAN (Switched Port Analyzer), is a method of monitoring network traffic. With port mirror enabled, the router sends a copy of all network packets seen on one port (or an entire VLAN) to another port, where the packet can be analyzed.
The target port is the mirrored port. The data passing through the target port is mirrored to the “monitor port”.
A mirrored port that monitors the flow of data through the original target port.
LAN1, LAN2, WAN, etc. on this section are the interfaces marked on the router panel, not LAN1, LAN2, that in the network configuration.