What is CIDR when addressing a network subnet?

What is CIDR when addressing a network subnet?

• Classless Inter-Domain Routing
• Class Inter-Domain Routing
• Classless Inter-Domain Racking
• Drinking apple CIDR with a kick before starting 

EXPLANATION

  Classless Inter Domain Routing (CIDR) is a method for assigning IP addresses without using the standard IP address classes like Class A, Class B or Class C. CIDR is a newer addressing scheme for IP Networks which allows for a more efficient allocation of IP addresses than the older method which was by assigning organizations a class of IPs. CIDR was a result of running out of IPv4 addresses as well as addressing the issue with routing tables increasing in size.

There is a maximum number of networks and hosts that can be assigned unique IP addresses using the 32 bit addressing. Traditionally, the Internet assigned "classes" of addresses: Class A, Class B and Class C were the most common. Many large organizations were assigned Class A blocks. Others were assigned Class B blocks. The smaller organizations were assigned Class C blocks. Not all organizations used all of the IP addresses within the block they were assigned. This resulted in an inefficent use of the addressing scheme. For this reason, the Internet was, until the arrival of CIDR, running out of address space very quickly. CIDR effectively solved the problem by providing a new and more flexible way to specify network addresses.

Class	Network Bits	Host Bits	Decimal Range
Class A	8	24	1-126
Class B	16	16	128-191
Class C	24	8	192-223