IP address
An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
An IP address serves two principal functions: host or network interface identification and location addressing.
PARC Universal Packet
The main internetwork layer protocol is PUP, which roughly corresponds to the Internet Protocol (IP) layer in TCP/IP. A full PUP network address consists of an 8-bit network number, an 8-bit host number, and a 16-bit socket number. The network number has a particular special value which means 'this network', for use by hosts which do not (yet) know their network number.