Auto-Negotiation

A key feature of the Sun Quad FastEthernet SBus adapter is auto-negotiation. The auto-negotiation protocol, as specified by the 100BASE-T standard, selects the operation mode (half-duplex or full-duplex), and the auto-sensing protocol selects the speed (10 Mbps or 100 Mbps) for the adapter.

The link speed and modes supported by the Sun Quad FastEthernet SBus adapter are listed as follows in decreasing order of priority:

• 100 Mbps, full-duplex

• 100 Mbps, half-duplex

• 10 Mbps, full-duplex

• 10 Mbps, half-duplex

When the system is booted, the Sun Quad FastEthernet SBus adapter advertises these capabilities to the Link Partner at the other end of the link (a hub, switch, or another network interface card (NIC) in a host system). If the Link Partner also supports auto-negotiation, it will advertise its capabilities over the link. The common highest priority mode supported by both sides will be selected automatically for the link operation.

If the adapter is connected to a system or interface that supports auto-negotiation, the adapter will operate at full-duplex mode. If the adapter is connected to a system or interface that does not support auto-negotiation, the auto-sensing protocol will select the speed and the adapter will operate in half-duplex mode. If you have disabled the auto-negotiation protocol on your system, the auto-sensing protocol will select the speed and the adapter will operate in full-duplex mode (unless you have forced the adapter to operate in half-duplex mode).

If the Sun Quad FastEthernet SBus adapter is connected to a link partner with which the auto-negotiation protocol fails to operate successfully, you can configure the device to not use this protocol and force the driver to set up the link in the mode and speed of your choice.