<How>

This dynamic routing protocol is Open Shortest Path First (OSPF), and OSPF is a link-state routing protocol. When using a link-state routing protocol, every router creates a "connectivity map" of the network. This is possible when each router advertises the details about its interface to its neighbors, which are passed on throughout all routers on the network.

Generally, link-state protocols are faster when reacting to changes in the network as opposed to distance vector protocols like RIP and IGRP. I will cover distance vector protocols in the next few labs, but for now, OSPF is the focus. Another thing to note is that OSPF is also more resource-intensive since its CPU is doing more work while info needs to be shared with other routers.

<How>

Imagine you have a network consisting of 25 routers and 2 out of the 25 have a link to the ISP, the link that is up and running now has issues. How will the rest of the routers know the next best path to the Internet Service Provider (ISP)? With OSPF, routers exchange Link-State Advertisements (LSA) with their neighboring routers and insert those into the routing table. This goes to show that using a routing protocol to share routes with neighboring routers makes it much more efficient than configuring static routes.

<Demonstration Video>

In this video, I'll demonstrate how to configure OSPF and ensure redundancy on a given network while troubleshooting for any connectivity issues.