What is route summarization and what is its primary benefit?

• A. Merging multiple subnets into a single summary to reduce routing table size and improve scalability.
• B. Listing all subnets individually for precise routing.
• C. Replacing dynamic routes with static routes to simplify management.
• D. Aggregating routes only for external networks to improve security.

Answer: (A)

Route summarization is the process of merging multiple subnets into one larger summary route. The primary benefit is reducing the size of the router’s routing table, which lowers memory and CPU usage and makes route lookups faster. By advertising a single summary for a group of subnets, the router can forward packets toward the correct exit point without maintaining a separate entry for every subnet, improving scalability as the network grows. There is a trade-off in granularity, since specifics about individual subnets are not exposed in the summary, but for many networks the efficiency gains are worth it.