WiFi WMM详解
一. WMM 基础
-
什么是WMM
-
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
-
WMM Information Element (include in probe request/association request)
-
WMM Parameter Element (include in probe response/association response/beacon)
-
QoS Data(include QoS Control Field)
二. RTP Transfer
-
Packet format(user priority in IP Header Diff Services[7:5])
- user priority为voice的802.11 mac header