Allied Telesis AT-S63 - Manual (Page 178)

Chapter 9: Port Mirroring
178 Section I: Basic Operations
Port Mirroring Overview
The port mirroring feature allows you to unobtrusively monitor the traffic
being received and transmitted on one or more ports on a switch by
having the traffic copied to another switch port. You can connect a network
analyzer to the port where the traffic is being copied and monitor the traffic
on the other ports without impacting network performance or speed.
The port(s) whose traffic you want to mirror is called the source port(s).
The port where the traffic will be copied to is called the destination port.
Observe the following guidelines when you create a port mirror:
ˆ You can select more than one source port at a time. However, the
more ports you mirror, the less likely the destination port will be able to
handle all the traffic. For example, if you mirror the traffic of six heavily
active ports, the destination port is likely to drop packets, meaning that
it will not provide an accurate mirror of the traffic of the six source
ports.
ˆ The source and destination ports must be located on the same switch.
ˆ You can mirror either the ingress or egress traffic of the source ports,
or both.