Special Edition Using TCP/IP, Second Edition

Subnetting

An IP address can be logically divided into two components: network ID and the host ID. The number of bits that are used to identify the network depends on the address class used. For example, if an organization has been assigned a class B address, the number of bits that can be locally administered by the organization is 16 bits. Therefore, a total of 2¹⁶–2 (2¹⁶–2) hosts can be connected to this network, which will be sufficient for the current requirements of the organization. However, if the organization requires multiple networks for its operations, it needs to acquire more Class B addresses based on its requirements. Instead of obtaining more class B addresses, the organization can divide the class B address that has been ...