What is Wi-Fi Multimedia?

Wi-Fi Multimedia (WMM), previously known as Wireless Multimedia Extensions (WME), is a subset of the 802.11e wireless LAN (WLAN) specification that enhances quality of service (QoS) on a network by prioritizing data packets according to four categories. Network administrators can change priority levels as they see fit.

Ranging from highest priority to lowest, these categories are:

• Voice: Giving voice packets the highest priority enables concurrent Voice over IP (VoIP) calls with minimal latency and the highest quality possible.
• Video: By placing video packets in the second tier, WMM prioritizes it over all other data traffic and enables support for three to four standard definition TV (SDTV) streams or one high definition TV (HDTV) stream on a WLAN.
• Best effort: Best effort data packets consist of those originating from legacy devices or from applications or devices that lack QoS standards.
• Background: Background priority encompasses file downloads, print jobs and other traffic that does not suffer from increased latency.

WMM also features a Power Save certification that helps small devices on a network conserve battery life. Power Save allows small devices, such as phones and PDAs, to transmit data while in a low-power "dozing" status. The certification gives software developers and hardware manufacturers a way to fine-tune battery use in the ever-increasing number of small devices that have Wi-Fi capabilities.

Devices and access points on a WLAN must be certified by the Wi-Fi Alliance to take advantage of WMM's QoS features. Source applications must also support WMM.

14 Oct 2008