LE(4)                 OpenBSD Programmer's Manual (PMAX)                 LE(4)

NAME
     le - DECstation AMD 7990 LANCE ethernet interface

SYNOPSIS
     le? at mainbus with le_pmax        (3100 baseboard)
     le*? at tc     with le_tc          (5000/200 baseboard)
     le? at ioasic  with le_ioasic      (ioasic baseboard)
     le* at tc?     with le_tc          (TC option cards)

DESCRIPTION
     The le driver provides access to a 10Mb/s Ethernet via the AMD 7990 LANCE
     Ethernet chip.  All LANCE interfaces on DECstations are supported, as are
     interfaces on Alpha AXP machines with a TurboChannel bus.

     The le driver employs the Address Resolution Protocol described in arp(4)
     to map between Internet and Ethernet addresses on the local network.  Se-
     lective reception of multicast Ethernet frames is provided by a 64-bit
     mask; multicast destination addresses are hashed to a bit entry using the
     Ethernet CRC function.

     No support is provided for switching between media ports.  The DECstation
     3100 provides both AUI and BNC  (thinwire or 10base2) connectors.  Port
     selection is via a manual switch and is not software configurable.  The
     DECstation model 5000/200 PMAD-AA baseboard device provides only a BNC
     connector.  The ioasic baseboard devices and  the PMAD-AA TurboChannel
     option card provide only an AUI port.

SEE ALSO
     arp(4), inet(4), intro(4), ioasic(4), tc(4)

BUGS
     On all front-ends, performance is impaired by hardware which forces a
     software copy of packets to and from DMA buffers.  The ioasic machines
     and the DECstation 3100 must copying packet to and from non-contiguous
     DMA buffers.  The DECstation 5000/200  and the PMAD-AA must copy to and
     from an onboard SRAM DMA buffer.  The CPU overhead is noticeable, but all
     machines can sustain 10Mbit media speed.

HISTORY
     This le driver is derived from a driver that first appeared in 4.4BSD.
     Support for  multiple bus attachments first appeared in NetBSD 1.2.

OpenBSD 2.9                     August 6, 1996                               1
