What type of OSPF area is intended to reduce routing table size and improve efficiency?

The type of OSPF area that is specifically designed to reduce routing table size and improve efficiency is the stub area. In a stub area, external routes from other autonomous systems (AS) are not advertised; instead, these areas are configured to send a default route to the internal routers. This significantly simplifies the routing table within that area, as routers do not need to store multiple external paths. Consequently, stub areas reduce the amount of routing information that routers must process, leading to enhanced performance and quicker convergence times.

The stub area achieves this by allowing internal OSPF routers to only maintain the routes to other networks within the area and the default route toward external networks, thus minimizing unnecessary routing updates and conserving resources. This is particularly useful in scenarios where external routes are either not needed or can be effectively summarized.

In contrast, the other area types serve different purposes. A totally stubby area goes a step further by not only discarding external routes but also inter-area routes, allowing only intra-area routing and a default route, which can further minimize routing complexity. A not-so-stubby area (NSSA) allows for some external routes to be introduced but retains the benefits of a stub area. The backbone area serves as the backbone of the OSP