Under what condition does OSPF perform route summarization?

OSPF, or Open Shortest Path First, performs route summarization specifically at area boundary routers for the purpose of improving efficiency and reducing the size of routing tables. This summarization occurs when routing information from one area is summarized and advertised to other areas, minimizing the amount of detailed route information that needs to be exchanged across area boundaries.

By summarizing the routes, OSPF reduces the overhead in routing updates and helps optimize the routing process, as the routers in other areas do not need to maintain detailed information about every individual route in the summarizing areas. This efficiency is particularly beneficial in larger OSPF networks, where maintaining complete route information for every individual subnet can lead to increased processing and memory overhead.

In contrast to other options, OSPF does not perform summarization under the conditions stated in those alternatives. Summarization is not limited to routers within the same area, nor does it depend on the size of link-state advertisements or serve as a solution for routing table overflow. Summarization is specifically designed for inter-area communication at area boundary routers.