3Com Switch 8800 Advanced Software V5 Configuration Guide

10
PORT MIRRORING CONFIGURATION
When configuring port mirroring, go to these sections for information you are
interested in:
■ “Introduction to Port Mirroring” on page 83
■ “Configuring Local Port Mirroring” on page 84
■ “Configuring Remote Port Mirroring” on page 85
■ “Displaying Port Mirroring” on page 87
■ “Port Mirroring Configuration Example” on page 87
Introduction to Port
Mirroring
Classification of Port
Mirroring
There are two kinds of port mirroring: local port mirroring and remote port
mirroring.
■ Local port mirroring copies packets passing through one or more ports (known
as source ports) of a device to the monitor port (also destination port) for
analysis and monitoring purpose. In this case, the source ports and the
destination port are located on the same device.
■ Remote port mirroring implements port mirroring between multiple devices.
That is, the source ports and the destination port can be located on different
devices in a network. Currently, remote port mirroring can only be
implemented on Layer 2.
Implementing Port
Mirroring
Port mirroring is implemented through port mirroring groups, which fall into these
three categories: local port mirroring group, remote source port mirroring group,
and remote destination port mirroring group.
Port Mirroring can be implemented as follows:
■ Local port mirroring is implemented by local port mirroring groups. The source
ports and the destination port are on the same device. In this case, packets
passing through the source ports are duplicated and then are forwarded to the
monitor port.
■ Remote port mirroring can be implemented by remote source port mirroring
groups and remote destination port mirroring groups. The source and
destination ports are on different devices. In this case, packets passing through
source ports are broadcast in remote port mirroring VLANs through reflector
ports, and those with their VLAN IDs being the remote port mirroring VLAN IDs
of the remote port mirroring groups are forwarded to the destination port of