Cerio OW-200N2, User Manual

Page: 36 / 290

User’s Manual
500mW eXtreme Power 11Na Outdoor Bridge
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By increasing the beacon interval, you can reduce the number of beacons and associated
overhead, but that will likely delay the association and roaming process because stations
scanning for available access points may miss the beacons. You can decrease the beacon
interval, which increases the rate of beacons. This will make the association and roaming process
very responsive; however, the network will incur additional overhead and throughput will go down.
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DTIM Interval : The DTIM interval is in the range of 1 ~ 255 . The default is 1 .
DTIM is defined as Delivery Traffic Indication Message . It is used to notify the wireless stations, which support
power saving mode, when to wake up to receive multicast frame. DTIM is necessary and critical in wireless
environment as a mechanism to fulfill power-saving synchronization.
A DTIM interval is a count of the number of beacon frames that must occur before the access
point sends the buffered multicast frames. For instance, if DTIM Interval is set to 3, then the
Wi-Fi clients will expect to receive a multicast frame after receiving three Beacon frame. The
higher DTIM interval will help power saving and possibly decrease wireless throughput in
multicast applications.
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Fragment Threshold : The Fragment Threshold is in the range of 256 ~ 2346 byte. The default is 2346 byte.
Each Wi-Fi packet can be divided into smaller packets, marked with a sequential fragment number and
re-assemble in the receiving ends. The purpose is to make a short frame, instead of long frame, transmitting by
radio in a heavy noisy environment. Because of sending smaller frames, corruptions are much less likely to occur.
The pros is obvious, the cons is the overhead for transmission. So, in a clean environment, higher fragment
threshold can be an option to increase throughput.
Fragmentation will be triggered by setting the Fragment Threshold, usually in Byte-length. Only
when the frame size is over the Threshold, fragmentation will take place automatically.
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RTS Threshold : TRTS Threshold is in the range of 1~2347 byte. The default is 2347 byte.
The main purpose of enabling RTS by changing RTS threshold is to reduce possible collisions
due to hidden wireless clients. RTS in AP will be enabled automatically if the packet size is larger
than the Threshold value. By default, RTS is disabled in a normal environment supports
non-jumbo frames.
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Short Preamble : By default, it’s “ Enable ”. To Disable is to use Long 128-bit Preamble Synchronization field.
The preamble is used to signal "here is a train of data coming" to the receiver. The short