Open Shortest Path First (OSPF) is a widely used interior gateway protocol (IGP) designed for routing within an autonomous system (AS). It is a link-state routing protocol that offers several key features:
Key Features of OSPF:
* Calculates Link Cost:
* OSPF assigns a cost to each link, representing the overhead required to send packets across that link. The cost is typically based on the link's bandwidth; higher bandwidth links have lower costs.
* OSPF uses these costs to calculate the shortest path to each network destination, ensuring efficient routing.
* Updates Routes Dynamically:
* OSPF routers exchange link-state advertisements (LSAs) to share information about network topology changes.
* When a change occurs, such as a link failure, OSPF quickly propagates this information, allowing routers to update their routing tables dynamically and converge on a new optimal topology.
Clarifications on Other Options:
* Option A: Utilizes distance vector
* OSPF is a link-state protocol, not a distance vector protocol. Distance vector protocols, like RIP, use different mechanisms for route calculation.
* Option C: Automatic redistribution of routes
* OSPF does not automatically redistribute routes from other routing protocols. Route redistribution between different protocols requires manual configuration.
* Option E: Uses exterior gateway protocols
* OSPF is an interior gateway protocol (IGP) used within a single autonomous system, not an exterior gateway protocol (EGP) like BGP, which is used between autonomous systems.
References:
* OSPF Design Guide
* Understanding OSPF