Service set (802.11 network)

(For example, all of the devices that together form and use a Wi‑Fi network called "Foo" are a service set.)

Each basic service set has a unique identifier, a BSSID, which is a 48-bit number that follows MAC address conventions.

As with the MAC addresses used for Ethernet devices, an infrastructure BSSID is a combination of a 24-bit organizationally unique identifier (OUI, the manufacturer's identity) and a 24-bit serial number.

[6] A temporary network created by a cellular telephone to share its Internet access with other devices is a common example.

The 802.11 standards prior to the 2012 edition did not define any particular encoding or representation for SSIDs, which were expected to be treated and handled as an arbitrary sequence of 0–32 octets that are not limited to printable characters.

IEEE Std 802.11-2012 defines a flag to express that the SSID is UTF-8-encoded and could contain any Unicode text.

[12] Wireless network stacks must still be prepared to handle all possible values in the SSID field.

[16] Once a device has associated with a basic service set, for efficiency, the SSID is not sent within packet headers; only BSSIDs are used for addressing.

[18] Key to the concept is that the participating basic service sets appear as a single network to the logical link control layer by using the same SSID.

[18][19] Thus, from the perspective of the logical link control layer, stations within an ESS may communicate with one another, and mobile stations may move transparently from one participating basic service set to another (within the same ESS).