Loopback interfaces are indeed often used with routing protocols as ospf, bgp, eigrp.
The advantage is that loopback interfaces are always up, because they are virtual. If they can be reach depends ofcourse on your routing protocol.
Ik you have for example a router with 3 physical interfaces all connected and your routing is configured correctly then the remote side can always reach your loopback till all paths (physical) are down.
But there are a lot more reasons to use loopbacks, but i think this one is the most important one.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...