fic and a second set of addresses for external traffic. A NAT box located where the LAN meets the Internet makes all necessary IP address translations. NCP (network control program) NCP (network control program) Software that represents a centralized database that stores a subscriber's unique VPN information. The NCP screens every call and applies call pro- cessing according to customer-defined requirements. near-end crosstalk Unwanted energy transferred from one circuit usually to an adjoining circuit. It occurs at the end of the transmission link where the signal source is located, with the absorbed energy usually propagated in the opposite direction of the absorbing channel's normal current flow. Near-end crosstalk is usually caused by high-frequency or unbalanced signals and insufficient shielding. NetBIOS (Network Basic Input/Output System) A session-layer interface that is widely used in PC networks. NetBIOS extended user interface A transport-layer protocol designed to support NetBIOS over 802.2 LANs. network (1) A collection of devices connected by communication lines for data processing or information interchange. (2) A series of points connected by communications channels. (3) A collection of telephone lines normally used for dialed telephone calls. (4) A group of computers and peripherals that are interconnected so that they can communicate with each other. network architecture The philosophy and organizational concept for enabling communica- tions between data-processing equipment at multiple locations. The network architecture speci- fies the processors and terminals and defines the protocols and software that must be used to accomplish accurate data communications. network control In a network, the establishment, authorization, and maintenance of logical and physical connections between stations and applications, plus the synchronization, routing, integrity, and recovery of data transmitted during the established connections. network layer In the OSI model, the logical network entity that services t