Which OSPF area type is likely to have the least amount of routing information?

The Totally Stub area is characterized by having the least amount of routing information among OSPF areas. In a Totally Stub area, routers are configured to prevent the advertising of external routes and summary routes from other OSPF areas. This means that only the routers within that specific area share routing information, which significantly reduces the complexity and volume of routing updates.

Totally Stub areas will typically only receive default routes from the Backbone area, which effectively minimizes the amount of routing information they maintain. This simplifies routing tables and reduces the amount of processing power required on the routers, thus optimizing performance, especially in environments with limited resources.

In contrast, other area types, such as the Backbone area and Normal area, carry a full routing table and can exchange complex routing information between different areas. The Stub area reduces this further by allowing only inter-area routes and not external routes, but still has more routing information compared to a Totally Stub area. As a result, choosing a Totally Stub area is especially beneficial in networks where reduced routing overhead is a priority.