IgniteNet SunSpot AC1200, Руководство пользователя

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Chapter 4
| Wireless Settings
Radio Settings
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WMM — Sets the WMM operational mode on the access point. When enabled,
the parameters for each Access Category (AC) queue will be employed on the
access point and QoS capabilities advertised to WMM-enabled clients.
(Default: Enabled)
When enabled, WMM must be supported on any device trying to associated
with the access point. Devices that do not support this feature will not be
allowed to associate with the access point.
Wireless networks offer an equal opportunity for all devices to transmit data
from any type of application. Although this is acceptable for most applications,
multimedia applications (with audio and video data) are particularly sensitive
to the delay and throughput variations that result from this “equal opportunity”
wireless access method. For multimedia applications to run well over a wireless
network, a Quality of Service (QoS) mechanism is required to prioritize traffic
types and provide an “enhanced opportunity” wireless access method.
The access point implements QoS using the Wi-Fi Multimedia (WMM) standard.
Using WMM, the access point is able to prioritize traffic and optimize
performance when multiple applications compete for wireless network
bandwidth at the same time. WMM employs techniques that are a subset of the
IEEE 802.11e QoS standard and it enables the access point to inter-operate with
both WMM-enabled clients and other devices that may lack any WMM
functionality.
Access Categories — WMM defines four access categories (ACs): voice, video,
best effort, and background. These categories correspond to traffic priority
levels and are mapped to IEEE 802.1D priority tags (see
Figure 2, “WMM Access
Categories", on page 41 ). The direct mapping of the four ACs to 802.1D
priorities is specifically intended to facilitate inter operability with other wired
network QoS policies. While the four ACs are specified for specific types of
traffic, WMM allows the priority levels to be configured to match any network-
wide QoS policy. WMM also specifies a protocol that access points can use to
communicate the configured traffic priority levels to QoS-enabled wireless
clients.
Table 2: WMM Access Categories
Access
Category WMM
Designation Description 802.1D
Tags
AC_VO (AC3) Voice Highest priority, minimum delay. Time-sensitive
data such as VoIP (Voice over IP) calls. 7, 6
AC_VI (AC2) Video High priority, minimum delay. Time-sensitive data
such as streaming video. 5, 4
AC_BE (AC0) Best Effort Normal priority, medium delay and throughput.
Data only affected by long delays. Data from
applications or devices that lack QoS capabilities. 0, 3
AC_BK (AC1) Background Lowest priority. Data with no delay or throughput
requirements, such as bulk data transfers. 2, 1