Monitoring and Analyzing Switch Operation

Traffic Mirroring

C o n f i g u r a t i o n N o t e s
Traffic Mirroring

Mirror Features

Feature

Default

Menu

CLI

Mirror CLI Quick Reference

n/a

n/a

B-34

Configure Mirror Source

disabled

page B-29

page B-35

Configure Mirror Destination at Source

disabled

page B-29

page B-35

Display Mirror Configuration

n/a

page B-29

page B-38

 

 

 

 

Traffic mirroring (Intelligent Mirroring) allows you to mirror (send a copy of) network traffic received or transmitted on a switch interface to a local destination, such as a traffic analyzer or intrusion detection system (IDS).

Traffic mirroring provides the following benefits:

Allows you to monitor the traffic flow on specific source interfaces

Helps in analyzing and debugging problems in network operation result- ing from a misbehaving network or an individual client. The mirroring of selected traffic to an external device makes it easier to diagnose a network problemfromacentralizedlocationinatopologyspreadacrossacampus.

Mirroring destinations. Traffic mirroring supports destination devices that are connected to the local switch:

Traffic can be copied to a destination connected to the same switch as the mirroring source in a local mirroring session. Up to four local mirroring destinations are supported on a switch.

Using the CLI, you can make full use of the switch’s local mirroring capabili- ties. Using the Menu interface, you can configure only local mirroring for a group of ports and/or static trunks.

Only a single mirror port session is supported.

Mirrored frames exceeding the allowed maximum transmission unit (MTU) size will be dropped. Also, the switch applies a 54-byte IPv4 header to mirrored frames. For more information, including the size limitation for jumbo and non- jumbo frames, see “Maximum Supported Frame Size” on page B-42.

Selecting mirrored traffic. You can use any of the following options to select the traffic to be mirrored on a port or trunk interface in a local session:

B-23