+CIDR (Classless Inter-Domain Routing) is a method for efficiently allocating [IP addresses](/wiki/ip_address) and routing [IP packets](/wiki/ip_packet). It replaced the old classful network addressing system, enabling more flexible and granular division of network space.
+## See also
+- [Subnet](/wiki/subnet)
+- [Routing](/wiki/routing)
+- [Network Mask](/wiki/network_mask)
... 1 more lines