NetBIOS is an interface for interprocess communications, not a protocol specification. Programs written to the NetBIOS interface should operate over a variety of protocol stacks. For instance, implementations of the NetBIOS interface exist for OS/2 using TCP/IP—that is, TCP/IP is used as the communication mechanism for the NetBIOS interface for the OS/2 operating system.
As Windows for Workgroups and IBM networking software both use NetBIOS with NetBEUI as a standard protocol, configuration of the NetBIOS protocol stack for these environments is carried out by the network software installation.
Within NetBIOS, communications can take place using a NetBIOS session or using the datagram service. NetBIOS sessions, or virtual circuits, are the default NetBIOS link for IQ. In a NetBIOS session, all communication between the client and server applications takes place in the context a reliable two-way connection between the two applications. Broadcast messages are not required in a session, so that network traffic outside the two communicating computers is affected less than when the datagram service is used.
