84
Port mirroring configuration
Introduction to port mirroring
Port mirroring is the process of copying the packets passing through a port/CPU to the monitor port
connecting to a monitoring device for packet analysis.
Terminologies of port mirroring
Mirroring source
The mirroring source can be one or more monitored ports or the CPUs. Packets (called “mirrored packets”)
passing through them are copied to a port connecting to a monitoring device for packet analysis. Such
a port/CPU is called a “source port/CPU” and the device where the port or CPU resides is called a
“source device”.
Mirroring destination
The mirroring destination is the destination port (also known as the monitor port) of mirrored packets and
connects to the data monitoring device. The device where the monitor port resides is called the
“destination device”. The monitor port forwards mirrored packets to its connecting monitoring device.
NOTE:
A monitor port may receive multiple duplicates of a packet in some cases because it can monitor multiple
mirroring sources. For example, assume that Port 1 is monitoring bidirectional traffic on Port 2 and Port 3
on the same device. If a packet travels from Port 2 to Port 3, two duplicates of the packet will be received
on Port 1.
Mirroring direction
The mirroring direction indicates that the inbound, outbound, or bidirectional traffic can be copied on a
mirroring source.
•
Inbound: Copies packets received on a mirroring source.
•
Outbound: Copies packets sent out a mirroring source.
•
Bidirectional: Copies packets both received and sent on a mirroring source.
Mirroring group
Port mirroring is implemented through mirroring groups, which fall into local, remote source, and remote
destination mirroring groups. For more information about the mirroring groups, see “
classification and implementation
Reflector port, egress port, and remote probe VLAN
A reflector port, remote probe VLAN, and an egress port are used for Layer 2 remote port mirroring. The
remote probe VLAN specially transmits 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. The
egress port must belong to the remote probe VLAN while the reflector port may not. For more information
about the source device, destination device, reflector port, egress port, and remote probe VLAN, see
“