Key Points of OSPF
- It uses different metrics to determine the best path for traffic, including cost, bandwidth, delay, reliability, and load.
- It uses the concept of administrative distance to determine which routing protocol to use when multiple protocols are configured on a router.
- OSPF elects a designated router (DR) and backup designated router (BDR) in each multi-access network to reduce the amount of traffic generated by neighbor discovery.
- OSPF supports authentication to ensure that only authorized routers can participate in the OSPF network. It also supports various features such as route summarization, virtual links, and route redistribution.
- OSPF supports IPv4 and IPv6 networks.
- It allows for the configuration of different types of network connections, including point-to-point, broadcast, and non-broadcast.
- OSPF messages include Hello packets, Link State Advertisement (LSA) packets, and Database Description (DBD) packets.
- OSPF has several types of areas, including standard areas, stub areas, totally stubby areas, and not-so-stubby areas (NSSAs).
- OSPF is widely used in enterprise networks and service provider networks due to its scalability, fast convergence, and support for hierarchical network design.
- OSPF has different types of LSAs, including router LSAs, network LSAs, summary LSAs, and AS external LSAs.
Configuring OSPF Interface Cost in Cisco
Pre-requisites: Open Shortest Path First (OSPF)
Open Shortest Path First (OSPF) is a routing protocol that exchanges routing information within an autonomous system (AS). it is a link-state protocol that provides a more efficient and scalable way of routing traffic compared to distance vector protocols like RIP.it uses a hierarchical network design with areas, where each area has its own link-state database and all routers within an area have identical information about that area. Dijkstra algorithmis used to calculate the shortest path between two points in a network, based on the link-state information available.