1. The router names are P4S1 and P4S2.
2. Create a loopback interface on either of the routers and specify an IP address to every loopback interface.
3. Delete the loopback interfaces.
1. The loopback interface is a logical virtual interface on the router. A router has no loopback interfaces by default, but they can be created on it. In normal cases, a router has fewer interfaces than a switch; therefore, you need to create loopback interfaces when doing lab. A loopback interface is treated on the router like a physical interface. It can be assigned an IP address. Loopback interfaces are widely used. They are enabled by default. To disable a loopback interface, run the shutdown command.
2. Create a loopback interface.
P4S1(config)#interface loopback ?
<0-2147483647> Loopback interface number
The range of the loopback interface is from 0 to 2147483647.
P4S1(config)#interface loopback 0
P4S1(config-if)#ip add 192.168.1.1 255.255.255.0