Wireless Multimedia Extensions (WME), also known as Wi-Fi Multimedia (WMM), is a
Wi-Fi Alliance
The Wi-Fi Alliance is a non-profit organization that owns the Wi-Fi trademark. Manufacturers may use the trademark to brand products certified for Wi-Fi
interoperability.
History
Early 802.11 products suffered from interoperability problems be ...
interoperability certification, based on the
IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...
802.11e standard. It provides basic
Quality of service
Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitat ...
(QoS) features to
IEEE 802.11
IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer commun ...
networks. WMM prioritizes traffic according to four Access Categories (AC): voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). However, it does not provide guaranteed
throughput
Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel, such as Ethernet or packet radio, in a communication network. The data that these messages contain may be delivered ov ...
. It is suitable for well-defined applications that require QoS, such as
Voice over IP
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of speech, voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms In ...
(VoIP) on
Wi-Fi
Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio wave ...
phones (
VoWLAN
Voice over Wireless LAN (VoWLAN), also Voice over WiFi (VoWiFi), is the use of a wireless broadband network according to the IEEE 802.11 standards for the purpose of vocal conversation. In essence, it is Voice over IP (VoIP) over a Wi-Fi netwo ...
).
WMM replaces the Wi-Fi DCF
distributed coordination function
Distributed coordination function (DCF) is the fundamental medium access control (MAC) technique of the IEEE 802.11-based WLAN standard (including Wi-Fi). DCF employs a carrier-sense multiple access with collision avoidance (CSMA/CA) with the bi ...
for
CSMA/CA
Carrier-sense multiple access with collision avoidance (CSMA/CA) in computer networking, is a network multiple access method in which carrier sensing is used, but nodes attempt to avoid collisions by beginning transmission only after the channel i ...
wireless frame transmission with
Enhanced Distributed Coordination Function (EDCF). EDCF, according to version 1.1 of the WMM specifications by the Wi-Fi Alliance, defines Access Categories labels AC_VO, AC_VI, AC_BE, and AC_BK for the
Enhanced Distributed Channel Access
''Enhanced'' is a 2019 Canadian-Japanese action film produced, written and directed by James Mark. The film premiered at the 2019 Toronto After Dark Film Festival.
Plot
A sinister government organization hunts down mutants, and one of such is a y ...
(EDCA) parameters that are used by a WMM-enabled station to control how long it sets its
Transmission Opportunity (TXOP), according to the information transmitted by the access point to the station. It is implemented for wireless QoS between RF media.
Power Save Certification
The Wi-Fi Alliance has added ''Power Save Certification'' to the WMM specification. Power Save uses mechanisms from 802.11e and legacy 802.11 to save power (for battery powered equipment) and fine-tune power consumption. The certification provides an indication that the certified product is targeted for power critical applications like Mobile/Smart Phones and portable power devices (I.e Those that require battery or recharging such as smart phones.)
The underlying concept of WMM PowerSave is that the station (STA) triggers the release of buffered data from the
access point (AP) by sending an uplink
data frame
A frame is a digital data transmission unit in computer networking and telecommunication. In packet switched systems, a frame is a simple container for a single network packet. In other telecommunications systems, a frame is a repeating structure s ...
. Upon receipt of such a data (trigger) frame the AP releases previously buffered data stored in each of its queues. Queues may be configured to be trigger enabled, (i.e. a receipt of a data frame corresponding to the queue acts as trigger), and delivery enabled, (i.e. data stored at those queues will be released upon receipt of a frame). Queues refer to the four ACs defined for WMM.
See also
*
802.11e: Quality of Service enhancements for Wi-Fi standard
802.11b
IEEE 802.11b-1999 or 802.11b is an amendment to the IEEE 802.11 wireless networking specification that extends throughput up to 11 Mbit/s using the same 2.4 GHz band. A related amendment was incorporated into the IEEE 802.11-2007 standard. ...
*
802.11e-2005 APSD (Automatic Power Save Delivery)
*
Sleep Proxy Service
Apple's Bonjour Sleep Proxy service is an open source component of zero-configuration networking, designed to assist in reducing power consumption of networked electronic devices.
A device acting as a sleep proxy server will respond to Multica ...
External links
Announcement about Power Save CertificationWMM Power Save Knowledge Center
Wireless networking