Allied Telesis AT-FS705PD - Manual (Page 13)

AT-FS705PD Fast Ethernet Switch Installation Guide
5
Port Speed
The twisted pair ports are compliant with the 10Base-T and 100Base-TX
standards and are capable of either 10 Mbps or 100 Mbps operation. Since the
ports are IEEE 802.3u Auto-Negotiation compliant, the switch will set the
port speed automatically. With Auto-Negotiation, the speed of the ports are
set automatically by the switch after it determines the speed of the end-node
connected to the port. Auto-Negotiation is designed to ensure that the port on
the switch and the end-node are operating at the same speed and that they
are communicating at the highest possible common speed between the
devices. For example, if an end-node is capable of only 10 Mbps, the switch
then sets the port connected to the end-node to 10 Mbps.
Duplex Mode
Duplex mode refers to the way an end-node sends and receives data on the
network. An end-node can operated in either half- or full-duplex mode
depending on its capabilities. An end-node that is operating in half-duplex
mode can either send data or receive data, but it cannot do both at the same
time. An end-node that is operating in full-duplex mode can send and receive
data simultaneously. The best network performance is achieved when an end-
node can operate at full-duplex, since the end-node is able to send and receive
data simultaneously.
Each twisted pair port on the AT-FS705PD switch can operate in either half-
duplex or full-duplex mode. Since these twisted pair ports are IEEE 802.3u-
compliant, the duplex mode can be set automatically through Auto-
Negotiation. With Auto-Negotiation, if the end-node is capable of full-duplex,
the port is set automatically to full-duplex mode. If the end-node is capable of
half-duplex, the port is set automatically to half-duplex mode.
Note
In order for a twisted pair port on the AT-FS705PD switch to
successfully Auto-Negotiate its duplex mode with an end-node, the end-
node should also be using Auto-Negotiation. Otherwise, a duplex mode
mismatch can occur. The twisted pair port, using Auto-Negotiation, will
default to half-duplex if it detects that the end-node is not using Auto-
Negotiation. This will result in a mismatch if the end-node is operating
at a fixed duplex mode of full-duplex.