Summarization
Summarization or route summarization is the process by which we can represent multiple routes using a single statement. This is often used for representing ranges of IPv4 addresses, as well as IPv6 addresses to a lesser extent.
For example, the following four /24 networks can be summarized using a single statement:
- 192.168.0.0 / 24 subnet mask 255.255.255.0
- 192.168.1.0 / 24 subnet mask 255.255.255.0
- 192.168.2.0 / 24 subnet mask 255.255.255.0
- 192.168.3.0 / 24 subnet mask 255.255.255.0
Summarized network: 192.168.0.0 /22 subnet mask 255.255.252.0
Summarization is often employed to make routing tables smaller as well in conjunction with the redistribution of routes in routing protocols such as OSPF and EIGRP.
Summarization should not be confused with the process of Supernetting.