C H A P T E R

C H A P T E R 1

The qfe Device Driver

This chapter gives a hardware overview of the SUNW,qfe device, provides information on the operating speeds and modes for the SUNW,qfe device, and discusses auto-negotiation. The following sections describe features of the SUNW,qfe device.

Supported Hardware

The qfe device driver handles the SUNW,qfe device on these hardware devices:

Sun Quad SBus Adapter
Sun Quad PCI Adapter

TABLE 1-1 Transceivers Available In Sun Adapters
Adapters	Transistors
SunQuad SBus Adapter	Internal only
SunQuad PCI Adapter	Internal only

Hardware Overview

The SUNW,qfe device provides 10BASE-T or 100BASE-T networking interfaces using the Fast Ethernet Parallel Port SCSI (FEPS) ASIC and an internal transceiver. The driver automatically sets the link speed to 10 or 100 Mbps and conforms to the 100BASE-T IEEE 802.3u Ethernet standard .

The FEPS (SBus based) ASIC provides the SBus interface and Media Access Control (MAC) functions. The PFEX (PCI-bus based) ASIC provides the PCI interface and Media Access Control (MAC) functions. The internal transceiver, which connects to an RJ-45 connector on all of the above hardware devices, provides the physical layer functions.

Operating Speeds and Modes

You can operate the link in either of the following speeds and modes with the SUNW,qfe device

100 BASE-T
10 BASE-T

The 100BASE-T I EEE 802.3u Ethernet Standard describes these speeds and modes.

Auto-Negotiation

The auto-negotiation protocol , as specified by the 100BASE-T IEEE 802.3u Ethernet Standard , selects the operation mode (half-duplex or full-duplex) at boot time or when the link state changes (the link fails or tries to connect). The auto-negotiation protocol also selects the speed and the full-duplex or half-duplex mode.

Details of the way the SUNW,qfe device uses auto-negotiation are provided in Appendix A .

The auto-negotiation protocol does the following:

Identifies all link partner-supported modes of operation
Advertises its capabilities to the link partner
Selects the highest common denominator mode of operation based on the following priorities (in decreasing order):
- 100 BASE-T
- 10 BASE-T

The link partner is the networking device (system, Ethernet hub, or Ethernet switch) at the other end of the link or cable.

If the SUNW,qfe device is connected to a remote system or interface that is not capable of auto-negotiation, the system automatically selects the correct speed and half-duplex mode.

If adapters or systems are connected to a link partner and the auto-negotiation protocol fails to operate successfully, you can configure the device so it does not use this protocol. This forces the driver to set up the link in the mode and speed of your choice.