Management and Configuration Guide K/KA/KB.15.15

Quick reference to remote mirroring setup
The commands beginning with “Configuring the mirroring destination on a remote switch” (page 322),
configure mirroring for a remote session in which the mirroring source and destination are on
different switches:
• The mirror command identifies the destination in a mirroring session.
• The interface and vlan commands identify the monitored interface, traffic direction, and
traffic-selection criteria for a specified session.
CAUTION: When configuring a remote mirroring session, always configure the destination switch
first. Configuring the source switch first can result in a large volume of mirrored, IPv4-encapsulated
traffic arriving at the destination without an exit path, which can slow switch performance.
High-level overview of the mirror configuration process
Determine the mirroring session and destination
For a local mirroring session
Determine the port number for the exit port (such as A5, B10, and so forth), then go to “Configure
the monitored traffic in a mirror session” (page 350).
For a remote mirroring session
Determine the following information and then go to “Configure a mirroring destination on a remote
switch” (page 349).
• The IP address of the VLAN or subnet on which the exit port exists on the destination switch.
• The port number of the remote exit port on the remote destination switch. (In a remote mirroring
endpoint, the IP address of the exit port and the remote destination switch can belong to
different VLANs.)
• The IP address of the VLAN or subnet on which the mirrored traffic enters or leaves the source
switch.
CAUTION: Although the switch supports the use of UDP port numbers from 1 to 65535,
UDP port numbers below 7933 are reserved for various IP applications. Using these port
numbers for mirroring can result in an interruption of other IP functions, and in non-mirrored
traffic being received on the destination (endpoint) switch and sent to the device connected
to the remote exit port.
• The unique UDP port number to use for the session on the source switch. (The recommended
port range is from 7933 to 65535.)
Configure a mirroring destination on a remote switch
This step is required only if you are configuring a remote mirroring session in which the exit port
is on a different switch than the monitored (source) interface. If you are configuring local mirroring,
go to “Configure a mirroring session on the source switch” (page 350).
For remote mirroring, you must configure the destination switch to recognize each mirroring session
and forward mirrored traffic to an exit port before you configure the source switch. Configure the
destination switch with the values you determined for remote mirroring in “High-level overview of
the mirror configuration process” (page 349).
NOTE: A remote destination switch can support up to 32 remote mirroring endpoints (exit ports
connected to a destination device in a remote mirroring session.)
High-level overview of the mirror configuration process 349