VLAN Mirrors

Creating a VLAN and setting a mirror for the VLAN allows you to monitor all traffic to your specified VLAN interface. For example, you could track all data traveling in and out of a confidential group of workstations, such as a Finance VLAN, by analyzing only one connection point. Considerations when configuring VLAN mirrors include:

A VTAP interface provides the data source input of a VLAN mirror. VTAP creation is the mechanism for adding a MIB-II interface table entry for a VLAN. A VLAN will not have a MIB-II ifIndex if a VTAP interface does not exist for it. Use the set vlan interface command to create a VTAP interface.