Overview - Allied Telesis AT-GS950/8 User Manual

Chapter 4: Port Mirroring

Overview

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The port mirroring feature allows you to unobtrusively monitor the traffic
received and transmitted on one or more ports by copying the traffic to
another switch port. You can connect a data analyzer to the port where the
traffic is copied and monitor the traffic on the other ports without impacting
network performance or speed.
A port mirror has two component ports. The port or ports whose traffic you
want to mirror is called the source port(s). The port where the traffic will be
copied to is called the mirroring port.
Observe the following guidelines when you create a port mirror:
You can select more than one source port at a time. However, the

more ports you mirror, the less likely the mirroring port is 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 does not provide an accurate mirror of the traffic of
the six source ports.
The source and mirror ports must be located on the same switch.

You can mirror the ingress or egress traffic of the source ports or

both.
While the Mirroring feature is enabled, the mirroring port is

dedicated to monitoring the traffic from the source ports and
cannot used for regular network operations.