By default, the dmfe driver performs auto-negotiation
to select the speed and mode of the link. Link speed and mode can be 100 Mbps
(full or half-duplex) or 10 Mbps (full or half-duplex) as described in the
100Base-TX standard.
The auto-negotiation protocol automatically selects speed mode (either
100 Mbps or 10 Mbps) and operation mode (either full-duplex or half-duplex)
as the highest common denominator supported by both link partners. Because
the dmfe device supports all modes, this effectively selects
the highest-throughput mode supported by the other device.
Alternatively, you can explicitly specify the link parameters by adding
entries to the dmfe driver configuration file (/platform/SUNW,UltraAX-i2/kernel/drv/dmfe.conf). You can set the speed parameter to 10 or 100 to force dmfe devices
to operate at the specified speed. Additionally, you can set the full-duplex
parameter to 0 or 1 to disable or force full-duplex operation, respectively.
Note that specifying either "speed" or "full-duplex" explicitly disables
auto-negotiation. To enable the driver to determine the appropriate setting
for each parameter, you should always set both parameters. If it is necessary
to force either speed or duplex setting (for example, because the dmfe device is connected to an ancient device or hub that does not
support auto-negotiation), both parameters should be explicitly specified
to match the requirements of the external device.
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