In the topology we have being configuring throughout this chapter, we can find that each router has two paths to reach each destination. So how about seeing how routers use these multiple paths together and load balancing the traffic across them.
We take RIP first because we do not have to do anything specific for load balancing. If there are multiple paths to reach a network destination with the same metric, RIP automatically load balances them. We will be using an interface type known as loopback to achieve this. A loopback is a virtual interface that behaves like a real interface and takes IP addresses.
We'll use the same topology we've been using throughout this chapter, and just add an extra interface. On router R4, we will add a loopback interface by using the following steps:
Unfortunately, it isn't possible to do this with the GUI, so go to the CLI tab of R4 and enter the following commands:
R4(config)#interface loopback 0 R4(config-if)#ip address...