WiFi WMM详解

一. WMM 基础

1. 什么是WMM
2. Priority mapping table , EDCA Prameter

                               802.1D与802.11E优先级映射

   Priority	UP（Same as 802.1D user Priority）	802.1D designation	AC	Designation （informative）
   Lowest                 Highest	1	BK	AC_BK	Background
   	2	-	AC_BK	Background
   	0	BE	AC_BE	Best Effort
   	3	EE	AC_BE	Best Effort
   	4	CL	AC_VI	Video
   	5	VI	AC_VI	Video
   	6	VO	AC_VO	Voice
   	7	NC	AC_VO	Voice

                                                                                           信道竞争参数

   AC	CWmin	CWmax	AIFSN	TXOP Limit（802.11b）	TXOP Limit（802.11a/g）
   AC_BK	aCWmin	aCWmax	7	0	0
   AC_BE	aCWmin	aCWmax	3	0	0
   AC_VI	（aCWmin+1）/2-1	aCWmin	2	6.016ms	3.008ms
   AC_VO	（aCWmin+1）/4-1	（aCWmin+1）/2-1	2	3.264ms	1.504ms

3. WMM Information Element (include in probe request/association request)
4. WMM Parameter Element (include in probe response/association response/beacon)
5. QoS Data(include QoS Control Field)

 

二. RTP Transfe

1. Packet format(user priority in IP Header Diff Services[7:5])

 

2, user priority为voice的802.11 mac header