User's Manual

that another station is already using the wireless medium. When these two stations send data
at the same time, they might collide when arriving simultaneously at the ODU. The collision
will most certainly result in a loss of messages for both stations. Thus, the RTS Threshold
mechanism will provide the solution to prevent data collisions. When the RTS is activated,
the station and its ODU will use a Request to Send/Clear to Send protocol (RTS/CTS). The
station will send an RTS to the ODU, informing that it is going to transmit the data. Upon
receipt, the ODU will respond with a CTS message to all station within its range to notify all
other stations to defer transmission. It will also confirm to the requesting station that the ODU
has reserved the channel for transmission.
Fragmentation Threshold: Fragmentation mechanism is used for improving the efficiency
when there is high traffic within the wireless network. If you transmit large files in a
wireless network, you can enable the Fragmentation Threshold and specify the packet size.
The mechanism will split the packet into the packet size you set.
TX Rate: When the ODU is under PXP, SAI, SAA, and SAA2, it provides various data rate
options for you to select. Data rates options include Fully Auto, Fixed 1Mb/s, Fixed 2Mb/s,
Auto Select 1M or 2M, Fixed 5.5Mb/s, and Fixed 11Mb/s. In most networking scenarios,
you will see that the factory-set default “Fully Auto” will prove the most efficient. This
setting will allow your 11Mbps Wireless LAN ODU to operate at the maximum data rate as
possib le. When the communications quality drops below a certain level, the ODU will
automatically switch to a lower data rate. Transmission at lower data speeds is usually more
reliable. However, when the communications quality improves again, the 11Mbps Wireless
LAN ODU will gradually increase the data rate again, until it has reached the highest
available transmit rate.