OSPF - Open Shortest Path First
Understanding OSPF
An extensive overview of the Open Shortest Path First (OSPF) protocol, detailing its functionality as a dynamic link-state routing protocol that utilizes the Shortest Path First (SPF) algorithm. It explains fundamental OSPF concepts, including areas, the backbone, Router IDs, and various types of routers such as Internal, Backbone, Area Border (ABR), and Autonomous System Boundary (ASBR). Furthermore, the text thoroughly describes the three main OSPF tables—Neighbor, Topology, and Routing—and outlines the cost metric calculation based on interface bandwidth. Finally, the document covers OSPF neighbor adjacency states, the election process for Designated Routers (DR) and Backup Designated Routers (BDR), and the behavior of OSPF across different network types, providing configuration examples for clarity.