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Wireless QoS
In the fields of wireless packet-switched networks and wireless networking,
the Wireless QoS (Quality of Service) refers to control mechanisms that can
provide different priority to different users or data flows for wireless
networks, or guarantee a certain level of performance to a data flow
transmitted through the wireless interface in accordance with requests from
the application program. QoS guarantees are important if the network
capacity is
limited,
applications, for example voice over IP and IP-TV, since these often require
fixed bit rate and may be delay-sensitive.
Wireless QoS is also referred to as Wi-Fi Multimedia (WMM), which is a
subset of 802.11e developed by Wi-Fi Alliance. WMM prioritizes traffic
according to 4 AC (Access Categories) - Voice, Video, Best Effort, and
Background. However, it does not provide guaranteed throughput. It is
suitable for simple applications that require QoS, such as Wi-Fi VoIP phone.
Access Categories (AC)
Voice
Priority
Video
Priority
Best Effort
Priority
Background
Priority
especially for
Highest priority
Allows multiple concurrent VoIP
calls, with low latency and toll
voice quality
Prioritize video traffic above
other data traffic
Traffic less sensitive to latency,
but affected by long delays, such
as Internet surfing.
Traffic from legacy devices, or
traffic from applications or
devices that lack QoS
capabilities
Low priority traffic (file
downloads, print jobs) that does
not have strict latency and
throughput requirements
Wireless IAD User Manual
real-time
streaming multimedia
7, 6
5, 4
3, 0
2, 1
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