What are two valid scaling techniques when an EIGRP network is designed that consists of more than 1000 routers? (Choose two.)

A structured hierarchical topology reduces the size of routing tables and the scope of queries, while route summarization aggregates routes to further reduce routing table size and improve convergence, significantly lowering processing overhead.

Using sub-second timers would increase the frequency of updates and hello messages, placing more load on routers and negatively impacting scalability in a large network.

Using distribute-lists filters routes but is a filtering mechanism, not a primary scaling technique for reducing overall routing table size or query scope in the way summarization or AS separation does.

Modifying delay parameters on links affects metric calculation but does not directly scale the EIGRP network's control plane or reduce routing table size for a large number of routers.

Implementing multiple EIGRP autonomous systems segments the network into smaller routing domains, which limits the propagation of routing updates and queries, thereby improving scalability and stability in very large networks.