D-Link dge-560t Ethernet Adapter page 5

that is supported by both modems, and to decide which is suitable for the
quality of the telephone-line connection between them. The parameters to be
settled between the two modems include best baud rate, compression method,
and error correction method. When the two modems have tested the phone-line
quality and have switched to the combination of parameters, which will
provide the best data communication, then you are given the "connect"
message which signals the end of the inter-modem negotiation and the
beginning of your intended communication with the remote computer.
Auto-negotiation between devices within an Ethernet LAN is similar in
concept, but much briefer. The two devices involved in the auto-negotiation
will be your D-Link DGE-560T and the switch or hub through which it is
connected into the LAN. (Switches ordinarily provide for auto-negotiation;
traditional hubs do not.) The parameters to be negotiated between the D-Link
DGE-560T and its supporting switch or hub include speed (1000Mbps =
Gigabit Ethernet, or 100Mbps = Fast Ethernet) and duplex mode (half-duplex
or full-duplex).
Startup communication between the two devices occurs when both devices are
operating, the cable connection between them is good, and the connected PC's
network software is loaded. As soon as those conditions are satisfied, the
preparatory process of auto-negotiation between the D-Link DGE-560T and its
supporting device begins and proceeds automatically.
If the supporting switch or hub has auto-negotiation functionality, then it and
the D-Link DGE-560T exchange a series of messages in which each device
signals its capabilities and listens for corresponding information about the
other. The auto-negotiation process requires only a few milliseconds, and the
two devices select the best communication parameters supported by both
devices.
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