Definitions for "Address Mask"
Keywords:  subnet, mask, subnetwork, inherent, bit
The address mask is used to identify the parts of an IP address that correspond to the different sections (separated by dots). It's also known as the "subnet mask" since the network portion of an address can be determined by the encoding inherent in an IP address.
a bit mask used to identify which bits in an address (usually an IP address) are network significant, subnet significant, and host significant portions of the complete address. This mask is also known as the subnet mask because the subnetwork portion of the address can be determined by comparing the binary version of the mask to an IP address in that subnet. The mask holds the same number of bits as the protocol address it references.
A bitmask used to select bits from an IP address. A logical ‘and' with the mask produces the network portion of the address. Hosts use address masks to determine if a destination IP address represents an adjacent host (allowing direct delivery), or if routing must be employed.