address mask

networking (Or "subnet mask") A bit mask used to identify

which bits in an IP address correspond to the networkaddress and subnet portions of the address. This mask is

often referred to as the subnet mask because the network

portion of the address can be determined by the class

inherent in an IP address. The address mask has ones in

positions corresponding to the network and subnet numbers and

zeros in the host number positions.

(1996-03-21)