Classless Inter Domain Routing (CIDR) is a method to allocate IP addresses and route IP packets.
I understand how it saves IP address space but I dont understand how it helps the routing process , Can someone enlightened me ??
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In the classful times when an organisation needed 4000 IPv4 addresses there were basically two options:
With CIDR (classless inter domain routing) we got rid of those classes and started using all prefix lengths. So instead of only being able to give them a /16 or a sixteen /24s it became possible to give them a /20: the required number of addresses in one single routing table entry.
Sanders has captured the RFC4632 in a simple manner. You can however, check this RFC4632 on why CIDR was implemented.