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Command: lan_config | Section: 8 | Source: Digital UNIX | File: lan_config.8.gz
lan_config(8) System Manager's Manual lan_config(8)
NAME
lan_config - Modifies low-level configuration parameters for a given
LAN interface
SYNOPSIS
/usr/sbin/lan_config -i interface_name
[-a [0|1]]
[-m [aui|bnc|utp|fiber]]
[-s [10|100]]
[-x [1|0]]
FLAGS
Changes the specified characteristics for interface_name. You must
provide an interface name. Enables (1) or disables (0) IEEE 802.3u au-
tonegotiation. This option applies only to those devices that are ca-
pable of autonegotiation (for example, DE500-AA and DE500-BA). When
enabled, the interface automatically negotiates the link speed (10 or
100 Mb/s) and the mode (half-duplex or full-duplex) with the remote in-
terface.
The interface initially advertises the speed and mode previously
selected at the console level or with the -s and -x options.
The -s and -x options may also be specified on the same command
line as the -a option to redefine and renegotiate the inter-
face's capability (when enabled) or to force the interface at a
certain configuration (when disabled).
Note
The interface initiates the autonegotiation process only if and
when it is up and running. See ifconfig(8) for information on
how the interface is marked up.
Changes the type of medium. The following table lists the sup-
ported types: tab(@); lfHB lfHB lfCW lw(2.25i). _
Type@Meaning
_
aui@10Base5, or thick wire bnc@10Base2, or ThinWire utp@10BaseT
(if speed is 10 Mb/s) or @100BaseT (if speed is 100 Mb/s), or
@twisted-pair fiber@100BaseFX only
_
On some devices, for example, DE435 and DE425, bnc selection is
done by means of an on-board gang jumper. When specifying aui
or bnc for these devices, be sure that the jumper is in the cor-
rect position. Changes the medium speed, if the interface is
capable of operating at both regular (10 Mb/s) and fast (100
Mb/s) Ethernet speeds. The fast speed cannot be selected for
the aui and bnc media. Enables (1) or disables (0) full-duplex
operation when the utp medium is specified.
DESCRIPTION
The lan_config command allows you to modify the type of medium, speed,
and mode of operation (half- or full-duplex).
You can also use the lan_config command to enable or disable autonego-
tiation, if the underlying device has this capability. Autonegotiation
is a hardware and software (driver) process that allows determination
of the highest common speed and duplex (half or full) configuration.
The permitted combinations of speed and mode of operation in descending
order of precedence, from the highest to the lowest, are: tab(~); lfHB
lfHB lfCW lw(2.25i). _
Speed~Mode
_
100 Mb/s~full-duplex 100 Mb/s~half-duplex 10 Mb/s~full-duplex 10
Mb/s~half-duplex
_
During autonegotiation, for example, if the local interface advertises
that it is capable of 100 Mb/s half-duplex operation, it is by implica-
tion also capable of 10 Mb/s, full-duplex and 10 Mb/s, half-duplex op-
eration. If the remote interface advertises that it is capable of 10
Mb/s, full-duplex operation only, the link is established at 10 Mb/s,
full-duplex. The autonegotiation process can take several seconds to
complete.
The characteristics managed with the lan_config command are ordinarily
set from the console level via the EWx0_MODE environment variable. The
lan_config command allows you to override this default and configure
the interface as needed after the system is up and running.
Modifications made with the lan_config command do not persist across
reboots of the operating system.
You can also use the ifconfig command to set the speed and mode (half-
or full-duplex) either from the command line or in the /etc/rc.local
file. If you specify the command in the rc.local file, the command is
executed each time the system is booted; you do not have to modify the
SRM console environment variables.
RESTRICTIONS
Support for the lan_config command is limited to the tu interface for
this release of DIGITAL UNIX.
EXAMPLES
To switch from aui or bnc to utp full-duplex operation on tu0, enter:
lan_config -i tu0 -m utp -x 1 To disable full-duplex operation on tu0,
enter: lan_config -i tu0 -x 0 To enable autonegotiation on tu1, limit-
ing capability to 100 Mb/s, enter: lan_config -i tu1 -a 1 -s 100 -x 0
To disable autonegotiation on tu1, forcing 10 Mb/s, half-duplex opera-
tion, enter: lan_config -i tu1 -a 0 -s 10 -x 1
RELATED INFORMATION
Commands: ifconfig(8).
Files: inet.local(4).
Interfaces: tu(7). delim off
lan_config(8)