Chapter 8: Port Mirroring
Overview
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.
