Internetworking: CIDR
Classless Interdomian Routing (CIDR)
Removes the classful address restriction
Extends the concept of subnetting to routers inside the Internet
Partially relieves address exhaustion, allows more efficient use of IPv4 address space
Supports deployment of arbitrarily sized networks
Aggregation allows reduction in the size of routing tables
From: Understanding IP Addressing: Everything You
Ever Wanted To Know By Chuck Semeria http://www.3com.com/nsc/501302.html