Basic OSPFv2 in depth

OSPF is one of the core topics of the CCIE R&S lab exam and therefore one should be an expert at it before attending the lab exam.

 In this post I would like to explore OSPFv2 and especially how OSPF uses its algorithm to find the best path to a destination. I will try to cover most of the general OSFP topics such as basic configuration, types of LSAs, Path selection, External path selection with LSA Type 5, Default routing, Conditional Default Routing, the different types of Stub areas, Virtual-links, LSA Type 3 filtering and Prefix filtering with route-maps. I have to admit that this post is quite long 🙂

 For this post I will use the following topology:

IGP: OSPF

Platform/IOS: Cisco 2691/12.4(15)T11 Adv IP services