Description: The purpose of this Lab is to configure
a loop back interface and test it for connectivity.
The loopback interface
is a logical interface internal to a router. It is not connected to
any other device. A loopback interface is UP as long as the router
is up and running. It is useful in managing a router as there will
always be at least one interface available on the router,
irrespective other physical interfaces.
The command used for
assigning loopback interface is
The number can be
between 0 and 2147483647
A loopback interface
is automatically put in "no shutdown" state when created.
However, you need to assign an ip address to use a loopback
1. Configure s0 on R1
with ip address and subnet mask as shown in the diagram.
2. Configure s0 and
loopback 1 on router R2 as shown in the diagram.
3. Ping loopback 1 and