The 802.11u standard is the base standard of IEEE. This standard essentially expands access points or hotspots with the ability to broadcast so-called "ANQP data packets "(Advanced Message Queuing Protocol) in its broadcast signals. ANQP is a query/response protocol that a device can use to request a range of information about the hotspot. This includes both meta-data, such as information about the owner and the venue, as well as information on the underlying network, such as information on operator domains, roaming partners, authentication methods, forwarding addresses, etc. All 802.11u-enabled devices in range have the ability to request these data packets without a prior login to the access point in order to select a network based on the network information.
The Wi‑Fi Alliance has added further ANQP elements to the standard, and markets this specification as Hotspot 2.0. This Hotspot 2.0 function merely adds additional elements to the standard, which the device can use as criteria for selecting its network. These criteria include, for example, information about the services and WAN metrics available at the hotspot. The associated certification program is called Passpoint®, which is available in different versions. Certain LANCOM access points are Wi‑Fi Alliance Passpoint® CERTIFIED (Release 1 and/or 2).
- The signaling of 802.11u support in the beacons and probes of a hotspot are done by the element known as the Interworking element. In this element, the initial basic network information—such as the network classification, Internet availability (Internet bit) and the OI of the roaming consortium and/or of the operator—are already included. At the same time, it is used by 802.11u-enabled devices as an initial screening criterion when detecting a network.
- ANQP data packets are transferred within the so-called GAS containers. GAS stands for Generic Advertisement Service, and is the name of generic containers that allow a device to request additional internal and external information for the network selection from the hotspot, in addition to the information in the beacons. The GAS containers are transmitted on layer 2 by what are referred to as public action frames.
