Source : Free On-Line Dictionary of Computing

packet driver
     
         {IBM PC} {local area network} software that
        divides data into {packet}s which it routes to the network.
        It also handles incoming data, reassembling the packets so
        that {application program}s can read the data as a continuous
        stream.
     
        {FTP Software} created the specification for {IBM PC} packet
        drivers but {Crynwr Software} dominate the market and have
        done the vast majority of the implementations.
     
        Packet drivers provide a simple, common programming interface
        that allows multiple {application}s to share a {network
        interface} at the {data link} layer.  Packet drivers
        demultiplex incoming packets among the applications by using
        the network media's {standard packet type} or {service access
        point} field(s).
     
        The packet driver provides calls to initiate access to a
        specific packet type, to end access to it, to send a packet,
        to get statistics on the network interface and to get
        information about the interface.
     
        Protocol implementations that use the packet driver can
        coexist and can make use of one another's services, whereas
        multiple applications which do not use the driver do not
        coexist on one machine properly.  Through use of the packet
        driver, a user could run {TCP/IP}, {XNS} and a proprietary
        protocol implementation such as {DECnet}, {Banyan}'s,
        {LifeNet}'s, {Novell}'s or {3Com}'s without the difficulties
        associated with pre-empting the network interface.
     
        Applications which use the packet driver can also run on new
        network hardware of the same class without being modified;
        only a new packet driver need be supplied.
     
        There are several levels of packet driver.  The first is the
        basic packet driver, which provides minimal functionality but
        should be simple to implement and which uses very few host
        resources.  The basic driver provides operations to broadcast
        and receive packets.  The second driver is the extended packet
        driver, which is a superset of the basic driver.  The extended
        driver supports less commonly used functions of the network
        interface such as {multicast}, and also gathers statistics on
        use of the interface and makes these available to the
        application.  The third level, the high-performance functions,
        support performance improvements and tuning.
     
        {(http://www.crynwr.com/crynwr/home.html)}.
     
        (1994-12-05)