The process of combining multiple consecutive network IDs of the same IP address class into a single block. Supernetting, also known as classless interdomain routing (CIDR), is the reverse of subnetting.
Supernetting is typically used to conserve class B addresses by combining contiguous groups of class C addresses. The class C addresses must have the same high-order bits, and the subnet mask is shortened by borrowing bits from the network ID and assigning them to the host ID portion to create a custom subnet mask. For example, if a company has 2000 hosts on its TCP/IP network, it can assign IP addresses by