route summarization (route summarization)
There are two methods of assigning IP addresses: classful addressing and classless addressing. Classless addressing is now mainstream.
Subnet masks allow you to divide your network into subnets and perform route summarization.
*When performing route aggregation, it is necessary to use a static route or a routing protocol that supports classless routing.
I explained that subnetting makes the network more efficient and easier to operate because it allows you to properly size and operate the network.
However, there is also a drawback that the number of entries in the routing table handled by the router increases as the number of subnets increases. Considering the vast network of the Internet, it is easy to imagine that the number of entries that routers must handle will be enormous.
As the number of network entries increases, the load on routers also increases. In some cases, routing may not be processed in time.
*A routing table is a table that a router refers to when forwarding received packets. The correspondence between the destination network and the forwarding source interface or the IP address of the neighboring router's interface is described.
See network configuration below.