A Deep Dive into Inter-area and Intra-area Routes, External Routes, and Link Costs
Introduction: Open Shortest Path First (OSPF) is a robust and widely used routing protocol in computer networks, particularly in large-scale enterprise environments. One of the key aspects of OSPF is its path selection mechanism, which determines how routers choose the best path to reach a destination. In this blog post, we’ll delve into OSPF path selection, focusing on inter-area and intra-area routes, type 1 and type 2 external routes, and the significance of link costs in the routing decision process.
Understanding OSPF Routing Hierarchy: OSPF organizes routers and networks into areas to scale efficiently. Routers within the same area share a common link-state database, which contains information about the network topology. OSPF defines two types of areas: backbone area (Area 0) and non-backbone areas (other numbered areas). Inter-area and intra-area routes are determined based on the area boundaries.