Terminology

The following terms are used in port mirroring configuration.

The mirroring sources can be one or more monitored ports or CPUs. The monitored ports and CPUs are called source ports and source CPUs, respectively.

Packets passing through mirroring sources are copied to a port connecting to a data monitoring device for packet analysis. The copies are called mirrored packets.

The device where the mirroring sources reside is called a source device.

The mirroring destination connects to a data monitoring device and is the destination port (also known as the monitor port) of mirrored packets. Mirrored packets are sent out of the monitor port to the data monitoring device.

A monitor port might receive multiple copies of a packet when it monitors multiple mirroring sources. For example, two copies of a packet are received on Port 1 when the following conditions exist:

• Port 1 is monitoring bidirectional traffic of Port 2 and Port 3 on the same device.

• The packet travels from Port 2 to Port 3.

The device where the monitor port resides is called the destination device.

The mirroring direction specifies the direction of the traffic that is copied on a mirroring source.

• Inbound—Copies packets received.

• Outbound—Copies packets sent.

• Bidirectional—Copies packets received and sent.

	NOTE: For inbound traffic mirroring, the VLAN tag in the original packet is copied to the mirrored packet. For outbound traffic mirroring, the VLAN tag in the mirrored packet identifies the VLAN to which the packet belongs before it is sent out of the source port.

Port mirroring is implemented through mirroring groups, which include local, remote source, and remote destination groups. For more information about the mirroring groups, see "Port mirroring classification and implementation."

Reflector ports, remote probe VLANs, and egress ports are used for Layer 2 remote port mirroring. The remote probe VLAN is a dedicated VLAN for transmitting mirrored packets to the destination device. Both the reflector port and egress port reside on a source device and send mirrored packets to the remote probe VLAN. For more information about the reflector port, egress port, remote probe VLAN, and Layer 2 remote port mirroring, see "Port mirroring classification and implementation."

	NOTE: On port mirroring devices, all ports except source, destination, reflector, and egress ports are called common ports.