Introduction to Net Bios

        Net Bios provides a hardware-independent interface to a network
        transport facility. Two processes, on the same or different
        machines, use the Net Bios to exchange data. These processes
        depend on the Net Bios to perform error checking, sequencing, and
        routing.

        The services provided by the Net Bios can be broken into five
        groups.

        1.   General.
             Configuration and status.

        2.   Name.
             A process or machine is identified by a name. Multiple
             names are supported by each machine. Names may be added
             and deleted.

        3.   Session control.
             A virtual connection, or session, can be established
             between processes or applications. A process might
             establish multiple sessions with remote processes.
             Commands are provided for waiting for a connection
             request from another (LISTEN), making a connection
             request (CALL), and terminating a connection (HANG UP).

        4.   Session data transfer.
             Once a session is established, the Net Bios maintains
             tables that allow the process to specify the remote
             process for data transfer with a number, or handle.
             Send and receive commands are provided. In addition,
             a "receive any" command allows a process to receive
             messages from any of the sessions it has established.

        5.   Datagram.
             Datagrams provide a means to transfer data between
             processes without using the session mechanism. Messages
             may be sent to a given name, a group name, or to all
             processes. These type messages do not provide the
             same reliability as session data transfer, since the
             sender will not be notified when messages are
             undeliverable.




        Net Bios names

        The Net Bios supports user added names. A given machine on the
        network is known (i.e., can be found by other machines) by these
        names. Names are 16 characters long and should not contain the
        asterisk (*) character. Each Net Bios also has a permanent name,
        which consists of 10 characters of binary zeros followed by 6
        more characters which must be unique on the network (typically,
        this "node number" is in PROM on a LAN card or configurable by
        DIP switches). Up to 16 user names may be added to the Net Bios.
        These are kept in the "local name table".

        Data transfer and session establishment is normally associated
        with one of the local names. For example, a datagram may be
        "sent to" a name. A session request (CALL) would be associated
        with two names. The name used by the requester and the name of
        the process with which a session is desired.