Allied Telesis 2.6.1 manual Port Mirroring

70 AT-8800 Series Switch User Guide

the BCLIMIT parameter description for important information about packet rate limiting. The default value for this parameter is NONE. If packet storm protection limits are set on the switch, the PORT parameter must specify complete processing blocks.

The ability of the switch to limit packet reception rates for different classes of packets is dependent on the particular switch hardware. In particular, groups of ports may have to have the same limits set, and the same limit may be set for the different types of packets, depending on the hardware. Whenever packet rate limits are set on switches which have this type of constraint, the latest parameter values entered will supersede earlier values. When a command entered for specified ports changes the parameters for other ports, a message will indicate these changes.

The SHOW SWITCH PORT command displays the packet storm protection settings (Figure 12 on page 64).

SHOW SWITCH PORT=port-list

Port Mirroring

Port mirroring allows traffic being received and transmitted on a switch port to be sent to another switch port, the mirror port, usually for the purposes of capturing the data with a protocol analyser. This mirror port is the only switch port which belongs to no VLANs, and therefore does not participate in any other switching. Before the mirror port can be set, it must be removed from all VLANs except the default VLAN. The port cannot be part of a trunk group.

To set the mirror port (and remove it from the default VLAN) use the command:

SET SWITCH MIRROR={NONEport}

If another port was previously set as the mirror port, this command returns the previous mirror port to the default VLAN as an untagged port. Return this port to any VLANs to which it should belong, using the ADD VLAN PORT command, or set it as a tagged port using the SET VLAN PORT command if required.

Either traffic received on a port or traffic transmitted by the port, or both, can be mirrored. This setting and the source port(s) from which traffic is sent to the mirror port are specified using the command:

SET SWITCH PORT={port-listALL} MIRROR={NONERXTXBOTH}

Mirroring four or more ports may significantly reduce switch performance.

The MIRROR parameter specifies the role of these port(s) as a source of mirror traffic. If NONE is specified, no traffic received or sent on these port(s) will be mirrored. If RX is specified, all traffic received on these port(s) will be mirrored. If TX is specified, all traffic transmitted on these port(s) will be mirrored. If BOTH is specified, all traffic received and transmitted will be mirrored. Traffic will actually only be mirrored if there is a mirror port defined and if mirroring is enabled. The default is NONE.

Software Release 2.6.1 C613-02039-00 REV A