This is the documentation for the 20.08 version. Looking for the documentation of the latest version? Have a look here.

Loopback Interfaces

Loopback interfaces are internal interfaces available for use in TNSR for routing and other internal traffic handling purposes such as acting as a bridged virtual interface (Bridge Interfaces).

Loopback Configuration

Before a loopback interface can be configured, a loopback instance must be created by the interface loopback <name> command. This command enters config-loopback mode. The loopback must be given a unique name and a positive numeric instance identifier.

The following commands are available in config-loopback mode:


A required instance identifier. This value is used to generate the loopback interface name in TNSR in the form of loop<id>. For example, with an id of 1, the loopback interface name is loop1.


A brief text description of this loopback instance.


An optional MAC address to use for the loopback interface. If omitted, TNSR will generate a MAC in the form of de:ad:00:00:00:<id>.

Loopback Example

This example creates a new loopback object named mgmtloop with an instance identifier of 1:

tnsr(config)# interface loopback mgmtloop
tnsr(config-loopback)# instance 1
tnsr(config-loopback)# exit

Upon commit, the new interface will be available for use by TNSR. The interface will be designated loop<instance id>, in this case, loop1. It can then be configured in the same manner as other interfaces:

tnsr(config)# interface loop1
tnsr(config-interface)# ip address
tnsr(config-interface)# exit