Document of User guide would be updated based on the CR xos0066083 with the following information under mirroring examples:
The port-list is a list of monitor ports that transmit identical copies of mirrored packets.
The loopback-port is an unused port that is required when you mirror to a port-list.
The loopback-port is not available for switching user data traffic.
Certain L2 control protocol packets like STP, LACP, LLDP cannot be mirrored with one to many mirroring.