4.4BSD/usr/share/man/cat4/tahoe/enp.0

ENP(4)           BSD Programmer's Manual (Tahoe Architecture)           ENP(4)

NNAAMMEE
     eennpp - CMC 10 Mb/s Ethernet interface

SSYYNNOOPPSSIISS
     ddeevviiccee eennpp00 aatt vvbbaa?? ccssrr 00xxffffff4400000000 vveeccttoorr eennppiinnttrr

DDEESSCCRRIIPPTTIIOONN
     The eennpp interface provides access to a 10 Mb/s Ethernet network through a
     CMC ENP-20 controller.

     The hardware has 128 kilobytes of dual-ported memory on the VERSAbus.
     This memory is used for internal buffering by the board, and the inter-
     face code reads the buffer contents directly through the VERSAbus. The
     address of this memory is derived from the address specified in the con-
     figuration file.

     Each of the host's network addresses is specified at boot time with an
     SIOCSIFADDR ioctl(2).  The eennpp interface employs the address resolution
     protocol described in arp(4) to dynamically map between Internet and Eth-
     ernet addresses on the local network.

     The interface normally tries to use a ``trailer'' encapsulation to mini-
     mize copying data on input and output.  The use of trailers is negotiated
     with ARP. This negotiation may be disabled, on a per-interface basis, by
     setting the IFF_NOTRAILERS flag with an SIOCSIFFLAGS ioctl.

     Associated with each interface is a character device which is used to
     dowload, start, and reset the firmware in the controller.  Reading or
     writing the ``ram device'' reads or writes the writable control store in
     the controller.  Two ioctl(2) calls, ENPIOGO and ENPIORESET, are used to
     start and reset the firmware.

DDIIAAGGNNOOSSTTIICCSS
     eennpp%%dd:: ccaann''tt hhaannddllee aaff%%dd..  The interface was handed a message with ad-
     dresses formatted in an unsuitable address family; the packet was
     dropped.

SSEEEE AALLSSOO
     intro(4),  inet(4),  arp(4),  enpload(8)

HHIISSTTOORRYY
     The eennpp driver appeared in 4.3BSD-Tahoe.

BBUUGGSS
     The hardware is not capable of talking to itself.  The software imple-
     ments local sending and broadcast by sending such packets to the loop in-
     terface.  This is a kludge.

     The link level firmware does not support setting the board's Ethernet ad-
     dress.

4.3-Tahoe Berkeley Distribution  June 5, 1993                                1