Overview
4
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.
The twisted pair ports on the AT-FS724L switch can operate in either half-
duplex or full-duplex mode and can deliver up to 200 Mbps of bandwidth to the
end-nodes. 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 the twisted pair port on the AT-FS724L 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.
Auto MDI/MDI-X
A twisted pair port on a 10 Mbps or 100 Mbps Ethernet network device can
have one of two possible wiring configurations: MDI or MDI-X. A twisted pair
port on a PC, router, or bridge is typically wired as MDI, while a twisted pair
port on a switch or hubs is usually MDI-X.
To connect two 10 Mbps or 100 Mbps network devices together that have
dissimilar port wiring configurations, such as an MDI to MDI-X, you would
use a straight-through twisted pair cable. To connect two networks devices
that have the same wiring configuration, such as MDI to MDI, you would use
a crossover cable.
The AT-FS724L switch features automatic MDI/MDI-X. The twisted pair port
automatically determines the configurations of the port on the device to which
it is connected and then configures itself appropriately. For example, if a port
on a switch is connected to a port on a bridge, which is typically wired as MDI,
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