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New Member

ADDTS/DELTS requests in Call Admission Control

Hi All,

I have a doubt regarding this ADDTS/DELTS request in Call Admission Control Feature. It is mentioned many articles that these requests are sent by the client.  So are these requests sent by the Voice Call Application or the WLAN Driver ? 

If WLAN driver sends these packets then how come the WLAN driver knows about the Voice Call requirements?


If voice call application sends its requirements to driver, which eventually sends this to associated AP. then how the Application talks to driver for sending its Voice call requirements like Data Rate, MSDU size...etc..?



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VIP Purple

Hi Akhil,ADDTS request always

Hi Akhil,

ADDTS request always sent by a station (not by AP), But DELTS can be initiated by the station or the AP.

802.11 all about MAC sub-layer &  PHY, so these thing should be within MAC sublayer of the wireless card.



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New Member

Hi Nayanajith, Thanks For the

Hi Nayanajith,


Thanks For the reply,
I agree that ADDTS is sent by Station. but that was not my doubt. 
I read that ADDTS request should be sent whenever a call is started and DELTS should be sent whenever the call is stopped. So In this scenario how the WLAN Station knows when the call is going to start and end ...? and

How the Station knows about call requirements like Traffic type, TID , Direction ,Access Policy,

Inactivity interval..etc.?




Hello Akhil, can you tell us

Hello Akhil,


can you tell us why you asking if the ADDTS is sent by client wireless adapter or the call app ?

so we can help you , 


i guess the ADDTS is initiated by the phone adapter and the adapter send these info in 802.11 frame so the AP can understand it , it could be initiated by the call software , but the call software will tell the phone OS to force the wireless adapter to send this frame , 


if you want a final answer , open a case with the phone support team , and get the answer from the developers ,