Route Summarization

Keeping routing tables small helps conserve memory and can improve the time required by a router to forward packets. Route summarization allows an engineer to keep the routing tables more manageable, without limiting reachability. Instead of advertising routes for every subnet, a router advertises a single route that encompasses multiple subnets. Each router can forward packets to the same set of destinations, but the routing table is smaller. For example, instead of advertising routes,,, and so on—all subnets up through—a router could advertise a single route for, which includes the exact same range of addresses.

Route summarization works best when the subnet ...

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