Sunday, August 31, 2008

IEEE 802.11r WiFi roaming standard approved!

The newest Wi-Fi protocol, 802.11r, which has become the de facto "Wireless VoIP standard", is now a published standard of the Institute of Electrical and Electronics Engineers (IEEE) standards board.

ieee802-11-logo On this day, 29th August 2008, the IEEE has formally announced that 802.11r is approved. According to Wikipedia, IEEE 802.11r-2008 or fast BSS transition (FT) is an amendment to the IEEE 802.11 standard to permit continuous connectivity aboard wireless devices in motion, with fast and secure handoffs from one base station to another managed in a seamless manner.

The arrival of 11r is timely. Voice over Wi-Fi is expected to generate increased interest as more dual-mode Wi-Fi/cellular solutions are delivered this year. 802.11f provides a fast enough hand-off for data services, but that can take a second or two if cryptography is being used, so 802.11r was kicked off in 2004 to provide consistent connections. The handoffs take place in less than 50 milliseconds, rather than the several seconds needed to negotiate a secured connection.


Given the need to integrate with 802.11i security and 802.11e QoS standards, developing a workable standard for fast roaming is challenging. Not surprisingly, 11r defines a complex architecture, though one that is not expected to require forklift upgrades of existing hardware. But getting all the software right will be difficult.

Related readings:

802.11r strengthens wireless voice

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