Redistribution proces between IGP routing protocols especially with externally redistributed networks may cause problems like routing loops or suboptimal routing. In thic article we will look closer on particular scenarios of redistribution between them.
Before OSPF will start to work seamlessly, one very important thing has to be accomplished, neighbor relationship namely. Every router in the network has to pass through a few stages of establishing relationships process, before network reach full convergence. What exactly happens behind the scene during establishing of relationship ?
OSPF is definitely the most sophisticated internal routing protocol. There is a lot of things which distinguishes its from the other and one of them is complexity. It is very important to understand how works, how neighborhood is established, how OSPF packets flow in order to troubleshoot and debug its.
In both routing protocols OSPF and EIGRP route summarization and default route propagation are crucial, especially if you have complex network with a lot of prefixes. Properly implemented summarization can save a lot of router resources. Let’s check how to implement both features and what is “mystery” null0 interface involved in summarization.