Which of the following is a correct characteristic of OSPF?

OSPF, or Open Shortest Path First, is fundamentally designed as a link-state routing protocol. This means it operates by having each router maintain a complete view of the network topology by exchanging information about the state of its links with other routers. Each OSPF router builds a link-state database that reflects the current status of the network, allowing it to calculate the shortest path to any destination using algorithms like Dijkstra's.

This link-state characteristic enables OSPF to support features such as fast convergence and efficient routing updates. Unlike distance vector protocols, which only share routing tables at intervals and rely on the information from neighboring routers, OSPF allows routers to notify neighbors of changes in link states immediately. This results in a more reliable and efficient routing process, particularly in larger and more complex networks.

The other characteristics mentioned are inaccurate: OSPF does not operate as a distance vector protocol, it can function across multiple autonomous systems through OSPF areas, and it does not limit itself to only classful addressing, as it supports classless addressing schemes as well. This support for classless inter-domain routing (CIDR) allows for more efficient use of IP address space.