What is WMM (WiFi Multimedia)?
WMM maintains the priority of audio, video and voice, over other applications which are less time critical.Using QoS (Quality of Service) Wi-Fi Multi-Media (WMM) ensures that the applications that require better throughput and performance,are inserted in queues with higher priority. For example, video and audio applications are given higher priority over applications such as FTP.
In this way, in a phone conversation, you are less likely to hear delays. Watching video, you are more likely to see smooth action. This delays other network traffic of a less critical nature - such as downloading large files - where a small time delay is acceptable.
WMM defines the following four queues, in decreasing order of priority:
- Voice.The highest priority queue with minimum delay, which makes it ideal for applications such as voice over IP(VoIP) and streaming media.
- Video. The second highest priority queue with low delay is given to this queue. Video applications are routed to this queue.
- Best Effort. The medium priority queue with medium delay is given to this queue. Most standard IP applications use this queue.
- Background. Low priority queue with high throughput. Applications, such as FTP, that are not time-sensitive, but require high throughput,can use this queue.
WMM does not provide guaranteed throughput.WMM is a subset of the IEEE 802.11e standard. To function correctly, wireless clients need to support WMM.All NETGEAR wireless products support WMM.
Examples being WC7520 Controller, and WNDAPxxx Access points. WMM differs from the advanced QoS feature in other products - used by system administrators - in that QoS allows high or low priorities to be assigned to any traffic, not just to audio, video, or voice.
Power Save:
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.
This feature of WMM to save power might cause disconnects under certain conditions.
References:
WC7520 Wireless Controller manual: http://support.netgear.com/product/WC7520
WMM: http://en.wikipedia.org/wiki/Wireless_Multimedia_Extensions
WMM Powersave: http://www.wi-fi.org/knowledge-center/faq/how-does-wmm-power-save-work
Doc # 221 Rev 2.0 December 2013.