The manual summarization is a process of creating a summary route that will be used to represent multiple routes and can be used to reduce the sizes of routing tables in a network. EIGRP, unlike some other routing protocols such as OSPF, supports the manual summarization on any router within a network.
The manual summarization in EIGRP is configured on the per-interface basis.
EIGRP manual summarization
One of the advantages of EIGRP over some other routing protocols (like OSPF) is that manual summarization can be done on any router within a network. A single route can be used to represent multiple routes, which reduces the size of routing tables in a network.
Manual summarization is configured on a per-interface basis.