ET(4)

NAME
et - 10 Mb/s Ethernet interface

DESCRIPTION
The et interface provides access to a 10 Mb/s Ethernet network through an Acorn Ethernet/Cheapernet expansion card used as a link-layer interface. It differs from the en(4) driver in that the et driver is for Ethernet cards which use Intel's 82856 “LANCE” controller, whereas the en driver is for cards built around National Semiconductor's DP8390C “NIC” chip.

Each of the host's internet network addresses is specified at boot time with an SIOCSIFADDR ioctl. The et interface employs the address resolution protocol described in arp(4P) to dynamically map between Internet and Ethernet addresses on the local network. The ethernet hardware address of the interface is obtained from a unique rom on the card and cannot be changed by software.

The use of a ``trailer'' encapsulation protocol is negotiated with ARP. This negotiation may be disabled, on a per-interface basis, by setting the IFF_NOTRAILERS flag with an SIOCSIFFLAGS ioctl. The interface normally tries to use trailer encapsulation to minimize copying data on input and output only if the other end of a connection has requested trailers.

DIAGNOSTICS
et%d: iss %X, slot %d, address %s. This provides firmware revisions levels and the Ethernet hardware address, and is expected during autoconfiguration.

et?: at slot %d IGNORED, too many units. Too many Ethernet cards are plugged in for the version of the kernel. Recompilation of the kernel is necessary if this many interfaces are required.

et%d: failed memory test page no %d.

et: cycle %d, offset %d, wrote %x read %x at address %x. The memory on the Ethernet card has failed a simple memory test on initialisation. This is either because it is not correctly pulgged into the backplane, of the card is faulty and needs repair.

et%d: can't initialise, status %x. The controller chip on the Ethernet card has failed to initialise. This is a serious hardware error, the card need repairing.

The following diagnostics only occur when enabled by ``ifconfig et0 debug'' They indicate problems with the packet reception, and/or transmission. For details refer to the INTEL 82586 programming manual.

et%d: receive error: CRC/ALN/RSC/LEN/EOF.

et%d: xmt no CARRIER SENSE.

et%d: xmt no CTS.

et%d: xmt DMA underrun.

SEE ALSO
intro(4N), en(4), inet(4F), arp(4P), ifconfig(8)