The Free On-line Dictionary of Computing (30 December 2018):

packet driver

    IBM PC local area network software that
   divides data into packets which it routes to the network.
   It also handles incoming data, reassembling the packets so
   that application programs 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 applications 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://crynwr.com/crynwr/home.html).

   (1994-12-05)