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Q
S
O
Key index and type must match that configured on the clients.
N
:
OTE
In a mixed-mode environment with clients using static WEP keys and WPA,
select WEP transmit key index 2, 3, or 4. The access point uses transmit
key index 1 for the generation of dynamic keys.
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) 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 developing 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
Access Categories" on page
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 5: WMM Access Categories
Number
RADIUS
Value
Attribute
AC_VO
Voice
Highest priority, minimum delay. Time-sensitive data
(AC3)
such as VoIP (Voice over IP) calls.
AC_VI (AC2) Video
High priority, minimum delay. Time-sensitive data
such as streaming video.
AC_BE
Best Effort
Normal priority, medium delay and throughput. Data
(AC0)
only affected by long delays. Data from applications or
devices that lack QoS capabilities.
AC_BK
Background Lowest priority. Data with no delay or throughput
(AC1)
requirements, such as bulk data transfers.
– 99 –
C
HAPTER
99). The direct mapping of the four ACs to
| Wireless Settings
8
QoS
"WMM
7, 6
5, 4
0, 3
2, 1
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