Configuring a Loopback Interface

The loopback interface is always Up to ensure network reliability.

The loopback interface has the following features:

• The loopback interface is always Up and has the loopback feature.
• The loopback interface can be configured with the mask of all 1s.

Based on the preceding features, the loopback interface has the following applications.

• The IP address of a loopback interface is specified as the source address of packets to improve network reliability.
• When no Router ID is configured for dynamic routing protocols, the maximum IP address of the loopback interface is configured as the router ID automatically.

The following commands can be used to configure a loopback interface：

set l3-interface loopback {lo | <vrf-name>} address <ipv4-address> prefix-length 32

set l3-interface loopback {lo | <vrf-name>} address <ipv6-address> prefix-length 128

The following command creates a IPv4 loopback interface in the default VRF.

admin@Xorplus# set l3-interface loopback lo address 1.1.1.1 prefix-length 32
admin@Xorplus# commit

The following commands can be used to disable a loopback interface.

admin@Xorplus# set l3-interface loopback lo2 disable true
admin@Xorplus# commit	

The following commands can be used to bind the loopback interface to a VRF. Users can configure multiple loopback interfaces per VRF.

admin@Xorplus# set l3-interface loopback lo2 vrf vrf2
admin@Xorplus# commit