Operation Manual
VigorAP 902 User’s Guide 
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WMM is an abbreviation of Wi-Fi Multimedia. It defines the priority levels for four access 
categories derived from 802.1d (prioritization tabs). The categories are designed with 
specific types of traffic, voice, video, best effort and low priority data. There are four 
accessing categories - AC_BE , AC_BK, AC_VI and AC_VO for WMM. 
Available settings are explained as follows: 
Item Description 
WMM Capable 
To apply WMM parameters for wireless data transmission, 
please click the Enable radio button. 
APSD Capable 
APSD (automatic power-save delivery) is an enhancement over 
the power-save mechanisms supported by Wi-Fi networks. It 
allows devices to take more time in sleeping state and consume 
less power to improve the performance by minimizing 
transmission latency. 
The default setting is Disable. 
Aifsn 
It controls how long the client waits for each data transmission. 
Please specify the value ranging from 1 to 15. Such parameter 
will influence the time delay for WMM accessing categories. 
For the service of voice or video image, please set small value 
for AC_VI and AC_VO categories For the service of e-mail or 
web browsing, please set large value for AC_BE and AC_BK 
categories. 
CWMin/CWMax 
CWMin means contention Window-Min and CWMax means 
contention Window-Max. Please specify the value ranging from 
1 to 15. Be aware that CWMax value must be greater than 
CWMin or equals to CWMin value. Both values will influence 
the time delay for WMM accessing categories. The difference 
between AC_VI and AC_VO categories must be smaller; 
however, the difference between AC_BE and AC_BK categories 
must be greater. 










