NetBIOS (Network Basic Input/Output System)

NetBIOS (Network Basic Input/Output System)

NetBIOS (Network Basic Input/Output System) is an application programming interface (API) and a networking protocol that enables communication between computers in a local area network (LAN). It was originally developed by IBM in the 1980s and later implemented by Microsoft in its Windows operating systems, making it widely used in many business environments.

Purpose and Role

The primary purpose of NetBIOS is to provide an abstraction layer for applications to communicate with each other over a local network. It simplifies the process of sharing resources like files and printers, and supports session establishment, data transmission, and resource management.

The role of NetBIOS includes:

  • Name service: NetBIOS provides a mechanism for resolving computer names to IP addresses on a local network. This allows users to access computers and resources using their human-readable names rather than IP addresses.
  • Session service: NetBIOS establishes and manages connections between computers, enabling the exchange of data in a reliable and orderly manner.
  • Datagram service: NetBIOS supports the transmission of datagrams, or packets of data, between computers on a LAN. This allows for fast, connectionless communication between devices.


NetBIOS consists of several components:

  • NetBIOS API: The NetBIOS API provides a set of functions that enable software applications to interact with the NetBIOS protocol. These functions allow applications to establish sessions, send and receive data, and manage resources on a local network.
  • Name Service (NetBIOS-NS): The Name Service is responsible for translating computer names to network addresses. It manages the registration, resolution, and release of NetBIOS names on a local network.
  • Session Service (NetBIOS-SS): The Session Service establishes, maintains, and terminates connections between computers. It ensures reliable and ordered data transmission between devices.
  • Datagram Service (NetBIOS-DS): The Datagram Service enables the transmission of datagrams between computers on a LAN. It provides a connectionless, unreliable communication service.


NetBIOS has been an important protocol for local area networks, particularly in Windows-based environments. Its significance lies in:

  • Simplifying network communication: NetBIOS provides an abstraction layer for applications, allowing them to communicate with other devices on a local network without dealing with the complexities of lower-level networking protocols.
  • Resource sharing: NetBIOS enables the sharing of resources, such as files and printers, among computers in a LAN, making it easier for users to access and manage these resources.
  • Compatibility: NetBIOS has been widely implemented in Windows operating systems, making it a common protocol for communication in many business environments.

However, with the advent of more modern networking protocols like TCP/IP and DNS, the importance of NetBIOS has diminished. Many of its functions have been replaced or integrated with these newer protocols, and it is considered less relevant in today's networking landscape.

See Also