NetBIOS (short for Network Basic Input/Output System) is an API for communicating between two stations on a network, without having to know about the underlying network architecture, transport protocols or physical cabling. NetBIOS was introduced by IBM in 1984, and since then has appeared on many networks, either as the primary protocol or as a piggyback protocol based on the network's main protocol.
Application programs that are written for NetBIOS should work on any station that provides a NetBIOS interface. The Novell NetBIOS implementation uses the network's underlying IPX protocol for sending NetBIOS packets between stations.
NetBIOS over TCP/IP (NetBT), specified by RFC 1001 and RFC 1002, provides the NetBIOS programming interface over the TCP/IP protocol, extending the reach of NetBIOS client/server programs to the WAN and providing interoperability with various other operating systems.