dnet - Ethernet driver for DEC 21040, 21041, 21140 Ethernet
The dnet Ethernet driver is a multithreaded, loadable, clon-
able, STREAMS GLD driver. Multiple controllers installed
within the system are supported by the driver. The dnet
driver functions include controller initialization, frame
transmit and receive, functional addresses, promiscuous and
multicast support, and error recovery and reporting.
APPLICATION PROGRAMMING INTERFACE
The cloning character-special device, /dev/dnet, is used to
access all DEC 21040/21041/21140 devices installed in the
The dnet driver is dependent on /kernel/misc/gld, a loadable
kernel module that provides the dnet driver with the DLPI
and STREAMS functionality required of a LAN driver. See
gld(7D) for more details on the primitives supported by the
The device is initialized on the first attach and de-
initialized (stopped) on the last detach.
The values returned by the driver in the DL_INFO_ACK primi-
tive in response to a DL_INFO_REQ from the user are as fol-
o The maximum SDU is 1500 (ETHERMTU - defined in
o The minimum SDU is 0.
o The DLSAP address length is 8.
o The MAC type is DL_ETHER.
o The sap length value is -2, meaning the physical
address component is followed immediately by a 2-byte
sap component within the DLSAP address.
o The broadcast address value is the Ethernet/IEEE
broadcast address (FF:FF:FF:FF:FF:FF).
Once in the DL_ATTACHED state, the user must send a
DL_BIND_REQ to associate a particular Service Access Point
(SAP) with the stream.
The PCI configuration process varies from system to system.
Follow the instructions provided by the vendor.
Known Problems and Limitations
o On multiport cards (exception: Osicom (Rockwell)
RNS2340), the first port is the top port. (On the
Osicom RNS2340, the first port is the bottom port.)
o If the dnet driver fails to determine the correct
speed and duplex mode resulting in a corresponding
drop in performance, set the speed and duplex mode
using the dnet.conf file.
o The dnet driver incorrectly counts carrier lost or no
carrier errors while in full-duplex mode. There is no
carrier signal present when in full-duplex mode and it
should not be counted as an error.
o Version 4 SROM formats are not supported.
The /kernel/drv/dnet.conf file supports the following
For full duplex operation use full-duplex=1, for half
duplex use full-duplex=0. Half-duplex operation gives
better results on older 10mbit networks.
speed For 10mbit operation use speed=10, for 100mbit opera-
tion use speed=100. Certain 21140 based cards will
operate at either speed. Use the speed property to
override the 100mbit default in this case.
character special device
dnet configuration file
See attributes(5) for descriptions of the following attri-
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Architecture | x86 |
attributes(5), dlpi(7P), gld(7D) streamio(7I)
Writing Device Drivers
STREAMS Programming Guide
Network Interfaces Programmer's Guide
Man(1) output converted with