A proposed IEEE standard, 802.11k aims to provide key client feedback to wireless-LAN access points and switches. The proposed standard defines a series of measurement requests and reports that detail Layer 1 and Layer 2 client statistics. In most cases, access points or WLAN switches ask clients to report data, but in some cases clients might request data from access points.
Because 802.11k is designed to be implemented in software, existing WLAN equipment can be upgraded to support it. For the standard to be effective, both clients (WLAN cards and adapters) and infrastructure (access points and WLAN switches) will need to support it.
Here are some of the measurements 802.11k defines:
RF channel knowledge.
Transmit Power Control (TCP).
To improve roaming decisions, access points or WLAN switches can provide a site report to clients. The standard defines a beacon request, in which an access point asks a client to go to a specific channel and report all the access point beacons it hears. The access point collects the data, and it or a WLAN switch will analyze the beacon information, looking at details such as what services and encryption types each access point supports and how strongly the client heard the access point. Then the switch or access point generates an ordered list of access points, from best to worst service, called the site report.
Currently, access points and clients cannot share channel information. With 802.11k, an access point could have a client build a "noise histogram," which will display all non-802.11 energy on that channel. An access point also can request data about channel load or how long the channel was used during a given time. An access point or WLAN switch then will know if there's too much interference or traffic on a channel to use it for WLAN services.
From 802.11k makes WLANs measure up, Network World Tech Update, 03/29/04.
In our 802.11k forum.
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