Configuring a source switch in a remote mirroring session


[no] mirror 1 - 4 [name name-str] remote ip src-ip src-udp-port dst-ip [truncation]

Used on the source switch to uniquely associate the mirrored traffic in the specified session with a remote destination switch. You must configure the same source and destination parameters when you configure the same session on both the source and destination switches. (If multiple remote sessions use the same source and destination IP addresses, each session must use a unique UDP port value.)

When you execute this command, the following message is displayed:

Caution: Please configure destination switch first.
          Do you want to continue [y/n]?

  • If you have not yet configured the session on the remote destination switch, follow the configuration procedure in Configure a mirroring destination on a remote switch before using this command.

  • If you have already configured the session on the remote destination switch, enter y (for "yes") to complete this command.

1 - 4

Identifies the mirroring session created by this command.

name name-str

Optional alphanumeric name string used as an additional session identifier (up to 15 characters.)


The IP address of the VLAN or subnet on which the traffic to be mirrored enters or leaves the switch.

Associates the remote session with a UDP port number. When multiple sessions have the same source IP address src-ip and destination IP address dst-ip , the UDP port number must be unique in each session. The UDP port number used for a given session should be in the range of 7933 to 65535.

UDP port numbers below 7933 are reserved for various IP applications. Using them for mirroring can result in the interruption of other IP functions and in non-mirrored traffic being received on the destination switch and sent to a device connected to the remote exit port.

The configured UDP port number is included in the frames mirrored from the source switch to the remote destination switch (mirror endpoint), and enables the remote switch to match the frames to the exit port configured for the combined UDP port number, source IP address, and destination IP address..

For the remote session specified in the command, this is the IP address of the VLAN or subnet on which the remote exit port exists. (The exit port to which a traffic analyzer or IDS is connected is configured on the remote switch in section.) .)


Enables truncation of oversize frames, causing the part of the frame in excess of the MTU size to be truncated. Unless truncation is enabled, oversize frames are dropped. The frame size is truncated to a multiple of 18 bytes—for example, if the MTU is 1000 bytes, the frame is truncated to 990 bytes (55 * 18 bytes.)

The no form of the command removes the mirroring session and any mirroring source previously assigned to the session. To preserve the session while deleting a monitored source assigned to it.