H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 561)

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Wireless QoS Configuration
Support of the H3C WX series access controllers for features may vary by device model. Refer to
section "Feature Matrixes" in Compatibility Matrixes for details.
The sample output in this manual was created on the WX5004. The output on your device may
vary.
The grayed out functions or parameters on the Web interface indicate that they are not supported
or cannot be modified.
The models listed in this manual are not applicable to all regions. Please consult your local sales
office for the models applicable to your region.
Overview
An 802.11 network offers contention-based wireless access. To provide applications with QoS services,
IEEE developed 802.11e for the 802.11-based WLAN architecture.
While IEEE 802.11e was being standardized, Wi-Fi Alliance defined the Wi-Fi Multimedia (WMM)
standard to allow QoS provision devices of different vendors to interoperate. WMM makes a WLAN
network capable of providing QoS services.
Terminology
1) WMM
WMM is a wireless QoS protocol designed to preferentially transmit packets with high priority, thus
guaranteeing better QoS services for voice and video applications in a wireless network.
2) EDCA
Enhanced distributed channel access (EDCA) is a channel contention mechanism designed by WMM
to preferentially transmit packets with high priority and allocate more bandwidth to such packets.
3) AC
Access category (AC), is used for channel contention. WMM defines four access categories; they are
AC-VO (voice), AC-VI (video), AC-BE (best-effort), and AC-BK (background) in the descending order of
priority. When contending for a channel, a high-priority AC preempts a low-priority AC.
4) CAC
Connection admission control (CAC) limits the number of clients that are using high-priority ACs
(AC-VO and AC-VI) to guarantee sufficient bandwidth for existing high-priority traffic.
5) U-APSD