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Wi-Fi (WLAN, IEEE 802.11)

Wi-Fi, or IEEE 802.11, is the standard for wireless LANs, or WLANs. The abbreviation Wi-Fi stands for Wireless Fidelity, and resembles the Hi-Fi acronym. It represents a whole collection of protocols within the same family of Ethernet and Token Ring.

It is specified by [http://standards.ieee.org/getieee802/802.11.html various IEEE 802.11 specifications].

The 802.11 protocols specify a wireless shared network, which means that the maximum bandwidth is only available to one user at a time.

History

XXX - add a brief description of 802.11 history

Protocol dependencies

Example traffic

XXX - Add example traffic here (as plain text or Ethereal screenshot).

Ethereal

The 802.11 dissector is fully functional.

Note that whether you can capture 802.11 traffic, whether the traffic will look like Ethernet traffic or 802.11 traffic, and whether you can capture non-data traffic (management frames, control frames) depend on the operating system on which you're capturing, the version of that operating you're using, the type of 802.11 network adapter you're using, and the version of the driver for that adapter, and the version of libpcap you're using. See [http://www.ethereal.com/media.html the Ethereal Supported Capture Media page] and [http://www.ethereal.com/faq.html#raw_80211_sniff the Ethereal FAQ item on capturing raw 802.11 traffic], and the FAQ items below it on 802.11 capture support on particular operating systems, for more details.

Preference Settings

(XXX add links to preference settings affecting how 802.11 is dissected).

Example capture file

XXX - Add a simple example capture file. Keep it short, it's also a good idea to gzip it to make it even smaller, as Ethereal can open gzipped files automatically.

Display Filter

A complete list of 802.11 display filter fields can be found in the [http://www.ethereal.com/docs/dfref/w/wlan.html display filter reference]

Capture Filter

Note that older versions of libpcap won't support "wlan" - you might have to use "ether" or "link" on those versions. (Those versions won't support capturing raw 802.11 traffic, and might not support 802.11 capture at all.)

Discussion

Should most of the content be moved to the WLAN page, and only Wi-Fi described here (pointing to the WLAN page)? AFAIK, Wi-Fi is only a conformance issue, but not the protocol itself, or am I wrong here? - Ulf Lamping

As far as I can tell, WLAN is a concept and Wi-Fi refers to a given WLAN technology, namely based on the IEEE 802.11 protocol family. You'll find articles today about another technology, Wi-Max. I'd put pointers from the WLAN page to Wi-fi and to a new page Wi-Max (or WiMax). - Olivier Biot