Editing IEEE 802.11r-2008 (section)

==Rationale for the amendment==
802.11, commonly known as [[Wi-Fi]], is widely used for wireless local area communications. Many deployed implementations have effective ranges of only a few dozen meters, so, to maintain communications, devices in motion that use it will need to transition from one access point to another. In an automotive environment, this could easily result in a transition every five to ten seconds. 

Transitions are already supported under the preexisting standard. The fundamental architecture for transition is identical for 802.11 with and without 802.11r: the client device (known as the '''Station''', or '''STA''') is entirely in charge of deciding when to transition and to which BSS it wishes to transition. In the early days of 802.11, transition was a much simpler task for the client device. Only four messages were required for the device to establish a connection with a new BSS (five if counting the optional "I'm leaving" message (deauthentication and disassociation frame) the client could send to the old access point). However, as additional features were added to the standard, including [[802.11i]] with [[802.1X]] authentication and [[802.11e]] (QoS) or [[Wireless Multimedia Extensions]] (WMM) with admission control requests, the number of messages required went up dramatically. During the time these additional messages are being exchanged, the mobile device's traffic, including that from voice calls, cannot proceed, and the loss experienced by the user could amount to several seconds.<ref name=wright>{{Cite journal|url=https://mentor.ieee.org/802.11/file/04/11-04-0989-01-000r-metric-characterizing-transition-time-performance.ppt|title=Metrics for Characterizing BSS Transition Time Performance|date=2004-09-07|author=Wright, Charles|author2=Polanec, Chris}}</ref> Generally, the highest amount of delay or loss that the edge network should introduce into a voice call is 50&nbsp;ms.

802.11r was launched to attempt to undo the added burden that security and quality of service added to the transition process, and restore it to the original four-message exchange. In this way, transition problems are not eliminated, but at least are returned to the status quo ante.

The primary application currently envisioned for the 802.11r standard is [[voice over IP]] (VOIP) via mobile phones designed to work with wireless Internet networks, instead of (or in addition to) standard cellular networks.