Auto-Negotiation
A key feature of the Sun Quad FastEthernet PCI adapter is auto-negotiation. The auto-negotiationprotocol, 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 PCI 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 PCI 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.
The qfe device driver operates the SUNW,qfe devices by default in half-duplex mode only. If the Sun Quad FastEthernet PCI adapter is connected to a remote system or interface that is not capable of auto-negotiation, your system automatically selects the speed and half-duplex mode.
If the Sun Quad FastEthernet PCI 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.
Chapter 3 Configuring the Driver Software 17
