Assigning an IP address to a loopback interface

Loopback interfaces are always up, regardless of the states of physical interfaces. They can add stability to the network because they are not subject to route flap problems that can occur due to unstable links between a Layer 3 switch and other devices. You can configure up to eight loopback interfaces on a chassis Layer 3 switch devices. You can configure up to four loopback interfaces on a compact Layer 3 switch.

You can add up to 24 IP addresses to each loopback interface.

NOTE
If you configure the Brocade Layer 3 switch to use a loopback interface to communicate with a BGP4 neighbor, you also must configure a loopback interface on the neighbor and configure the neighbor to use that loopback interface to communicate with the Brocade Layer 3 switch. Refer to Assigning an IP address to a loopback interface.

To add a loopback interface, enter commands such as those shown in the following example. 

device(config-bgp-router)# exit
device(config)# interface loopback 1
device(config-lbif-1)# ip address 10.0.0.1/24

Syntax: interface loopback num

The num parameter specifies the virtual interface number. You can specify from 1 to the maximum number of virtual interfaces supported on the device. To display the maximum number of virtual interfaces supported on the device, enter the show default values command. The maximum is listed in the System Parameters section, in the Current column of the virtual-interface row.

Parent topic: Configuring IP addresses