C A U T I O N
QoS describes a range of technologies for controlling traffic on shared
network connections. The IEEE 802.11e - 2005 standard defines a QoS stan-
dard for transmission quality and availability of service on wireless networks.
QoS is designed to provide better network service by minimizing network
congestion; limiting jitter, latency, and packet loss; supporting dedicated
bandwidth for time-sensitive or mission-critical applications; and prioritizing
wireless traffic for channel access.
QoS on WLAN can be achieved by two means: by prioritized access to the
channel and by parameterized access to the channel. The prioritized access
to the channel implementation is called Wireless Multimedia (WMM) and the
parameterized access to the channel is called WSM.
IEEE 802.11e specifications for wireless QoS enhancements include packet
prioritization, scheduled access, and call admission control. Eager to spur
interoperability among multi-vendor wireless gear, the Wi-Fi Alliance created
a certification process on a subset of 802.11e called Wi-Fi Multi-media (WMM).
WMM provides four categories of relative QoS: voice, video, best-effort, and
background. Wi-Fi Alliance-based certification, including WMM, is supported
by many leading wireless vendors including ProCurve.
Both access points and wireless stations (laptops, consumer electronics
products) should be WMM-enabled in order to use this QoS feature.
The default WMM parameters settings are usually adequate for WMM opera-
tion. Incorrect WMM settings can adversely affect network performance.
Changes to WMM parameters should be reserved for someone with an
advanced knowledge of how WMM operates. For more on WMM, see the IEEE