EIGRP’s convergence time is heavily impacted by the size of the query domain — the group of routers involved when a route goes into active state. The larger the query domain, the longer the convergence. Summarization naturally bounds query propagation because routers receiving a summary have no knowledge of individual prefixes beyond that summary, preventing them from being queried about specifics they don’t track.

This design technique is emphasized in CCDE v3.1 because:

Summarization reduces the query scope.

Faster convergence happens as fewer routers process queries.

Hierarchical design is enabled for stability and scalability.

Why other options are incorrect:

A: Distribute lists filter prefixes but don ' t reduce query propagation.

B and C: Triangulated or squared physical topology doesn’t control protocol-level query scope.

E: Default routes may help limited routing domains but don’t optimize EIGRP convergence specifically.

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