Compex Systems 802.11N - Manual (Page 74)

Fragmentation Threshold: specifies the maximum size for a packet before data is fragmented
into multiple packets. The range is 256-2346 bytes, or word “off”. Setting the Fragmentation
Threshold too low may result in poor network performance.
The use of fragmentation can increase the reliability of frame transmissions. Because of sending
smaller frames, collisions are much less likely to occur. However lower values of the
Fragmentation Threshold will result lower throughput as well. Minor or no modifications of the
Fragmentation Threshold value is recommended while default setting of 2346 is optimum in most
of the wireless network use cases.
Station Isolation: This option allows packets only to be sent from the external network to the
CPE and vice verse (applicable for AP/AP WDS mode only). If the Client Isolation is enabled
wireless stations connected to the same AP will not be able to interconnect on both layer 2 (MAC)
and layer 3 (IP) level. This is effective for the associated stations and WDS peers also.
Acknowledgement Timeout
Device has an auto-acknowledgement timeout algorithm which dynamically optimizes the frame
acknowledgement timeout value without user intervention. This is a critical feature required for
stabilizing long-distance outdoor links. The user also has the ability to enter the value manually.
Distance: specify the distance value in miles (or kilometers) using slider or enter the value
manually. The signal strength and throughput falls off with range. Changing the distance value
will change the ACK Timeout to the appropriate value of the distance.
ACK Timeout: specify the ACK Timeout. Every time the station receives the data frame it sends
an ACK frame to the AP (if transmission errors are absent). If the station receives no ACK frame
from the AP within set timeout it re-sends the frame. The performance drops because of the too
many data frames are re-send, thus if the timeout is set too short or too long, it will result poor
connection and throughput performance.
Changing the ACK Timeout''== value will change the Distance to the appropriate distance value
for the ACK Timeout.
Auto: Adjust control and enable the ACK Timeout Self-Configuration feature. If enabled, ACK
Timeout value will be derived dynamically using an algorithm similar to the Conservative Rate
Algorithm described above. It is not recommended to use Auto Adjust option for long range links
if the signal level is low or the high level of interference is present.
If two or more stations are located at the considerably different distance from the Access Point, the
highest ACK Timeout for the farthest station should be set at the AP side. It is not recommended to
use Auto Adjust option for Point-to-Multipoint connections as it will not warrant highest network
performance in all the use cases.