Which routing protocols allow for address summarization between areas?

Address summarization is a critical feature in routing protocols that enhances routing efficiency and reduces the size of routing tables. In the context of the question, it's important to highlight the capabilities of the Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP) in performing address summarization across multiple areas.

OSPF, a widely used interior gateway protocol, supports summarization of routes at area boundaries, allowing administrators to aggregate a range of contiguous IP addresses into a single summary route. This is achieved through its ability to summarize routes at area border routers (ABRs) when advertising routes between OSPF areas.

BGP, an exterior gateway protocol, also supports address summarization, specifically when exchanging routing information between autonomous systems (AS). This capability is crucial for managing routing information on the internet, where it helps to optimize routing tables and facilitate efficient routing across different network segments.

While other routing protocols may have distinct characteristics regarding route management and summarization, OSPF's capability to summarize routes at area boundaries and BGP's ability to aggregate routes between ASes clearly demonstrate that both protocols do indeed allow for address summarization across multiple areas. This makes the selection of the response the most accurate in the context of the question.