Introduction; Acpi Power Management; Wake O Nlan; Flow Control - D-Link DFE-550TX User Manual

Thank you for choosing the D-Link DFE-550TX - the value leader among Fast Ethernet adapters for the
PCI-Bus. This introduction gives a general description of the newer networking technologies found on the
DFE-550TX.

ACPI Power Management

The DFE-550TX adapter complies with the Advanced Configuration and Power Interface 1.0 (ACPI)
specifications. ACPI is a new open industry specification providing power management support systems
through hardware and operating system cooperation. The DFE-550TX can reduce power consumption by
entering Sleep mode along with the host computer. Although in Sleep mode, the network interface card
(NIC) will continue to monitor the LAN looking for wake-up packets.
Wake On LAN
Wake On LAN (WOL) is an ACPI function allowing a powered down (sleeping) computer to be powered ON
from a remote station. To use the WOL feature, the NIC must be WOL capable and the motherboard of the
PC must be ACPI compliant.
While powered-down computers Sleep, WOL enabled NICs monitor LAN traffic for valid Wake-up frames.
When one is received, the NIC will immediately wake-up and send a signal to the motherboard to power ON
the computer.
Some uses for the WOL feature include:
Forgot a document and out of town? Send a Wake-up signal to your computer and retrieve the needed
file.
Initiate long routines and reports before you get to work.
Transfer files when the network traffic is low (during late hours).
Power ON your PC before you arrive to work.
The MIS department can upgrade software on computers after hours from a remote station.
WOL is very helpful in limiting the power consumption of PCs, workstations, and kiosks.

Flow Control

The DFE-550TX implements IEEE 802.3x compliant flow control for full duplex, which provides traffic
management functions for full-duplex operation. Flow control allows for enhanced full duplex operation with
switches. When operating at full duplex (requiring a direct connection to a switch) and the switch's data
buffer is about to overflow, a Pause frame will be transmitted to the DFE-550TX. The ensuing idle time
keeps the buffer from overflowing and prevents data from being lost. This enhancement can improve
network throughput, avoid collisions and prevent lost data, helping the network achieve optimal
performance.

IP Multicasting

The DFE-550TX uses chip-level address filtering when implementing IP Multicasting (defined in RFC
1112). This hardware-based implementation provides a huge performance increase over other interface
cards. Formerly, broadcast packets were used for multicasting, but they are a less than ideal solution for
transmitting packets to groups. This is because broadcast packets reach every terminal on the network,
creating undue traffic and occupying CPU time on all computers.
IP Multicasting is a much better way to send data to groups, especially since routers and even switches can
filter packets so they only reach those stations that are part of the group. The DFE-550TX goes one step
further by examining multicast packets on the card itself (rather than using the computer's CPU) and only
accepting those packets for the group(s) in which the host belongs, thus conserving CPU utilization.
This can be very useful since more and more multicast data, such as corporate messages to employees, stock
quotes, video and audio conferencing, and database replication is transmitted on today's networks.
D-Link DFE-550TX Ethernet Adapter

Introduction

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