Cisco 500 Series, Configuration Manual

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5-7
Cisco Security Appliance Command Line Configuration Guide
OL-12172-03
Chapter 5 Configuring Ethernet Settings, Redundant Interfaces, and Subinterfaces
Configuring VLAN Subinterfaces and 802.1Q Trunking
Changing the Active Interface
By default, the active interface is the first interface listed in the configuration, if it is available. To view
which interface is active, enter the following command:
hostname# show interface redundant number detail | grep Member
For example:
hostname# show interface redundant1 detail | grep Member
Members GigabitEthernet0/3(Active), GigabitEthernet0/2
To change the active interface, enter the following command:
hostname# redundant-interface redundant number active-member physical_interface
where the redundant number argument is the redundant interface ID, such as redundant1 .
The physical_interface is the member interface ID that you want to be active.
Configuring VLAN Subinterfaces and 802.1Q Trunking
This section describes how to configure a subinterface, and includes the following topics:
•
Subinterface Overview, page 5-7
• Adding a Subinterface, page 5-8
Subinterface Overview
Subinterfaces let you divide a physical or redundant interface into multiple logical interfaces that are
tagged with different VLAN IDs. An interface with one or more VLAN subinterfaces is automatically
configured as an 802.1Q trunk. Because VLANs allow you to keep traffic separate on a given physical
interface, you can increase the number of interfaces available to your network without adding additional
physical interfaces or security appliances. This feature is particularly useful in multiple context mode so
that you can assign unique interfaces to each context.
This section includes the following topics:
•
Default State of Subinterfaces, page 5-7
• Maximum Subinterfaces, page 5-8
•
Preventing Untagged Packets on the Physical Interface, page 5-8
Default State of Subinterfaces
When you add a subinterface, it is enabled by default. However, the physical or redundant interface must
also be enabled to pass traffic (see the
“Configuring and Enabling RJ-45 Interfaces” section on page 5-1 ,
the “Configuring and Enabling Fiber Interfaces” section on page 5-3 , or the “Configuring a Redundant
Interface” section on page 5-4 ).