Technology, Data Communication Terms, Glossary and Dictionary
Network Number is the part of an IP address that specifies the network to which the host belongs. In classless routing, IP addresses consist of a network number (the combination of the network number and subnet number) and a host number. In classful IP, the network number and host number are derived from the IP address using a bitmask whose value is determined by the first few bits of the IP address. In order to determine the network to which a given route applies, an IP host must know both the network number AND the subnet mask for that network.