What is an OSPF Inter-Area route?

An OSPF Inter-Area route refers to routes that are learned from other OSPF routers that reside in different areas. OSPF (Open Shortest Path First) is a link-state routing protocol that organizes networks into areas to optimize routing and manage bandwidth. When OSPF routers exchange information, they share routes within their own area as well as summarize and share routing information between different areas.

Inter-Area routes are identified by Type 3 Link-State Advertisements (LSAs), which are used to inform routers in one area about the network information present in another area. This type of route allows OSPF to maintain a hierarchical and segmented routing structure while still ensuring connectivity across the entire OSPF domain.

In contrast, routes learned from external sources refer to OSPF external routes (Type 5 LSAs) and are not classified as Inter-Area routes. Static routes configured on the router do not involve OSPF and are defined manually, while routes learned from OSPF routers within the same area pertain to intra-area routes rather than inter-area routes. Thus, the distinction lies in the origin of the routing information, which emphasizes the importance of understanding how OSPF structures its routing tables across different areas for efficiency