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BLOG: It’s all about u

Louis Au | Oct. 5, 2011
802.11u promises wi-fi users a cellular-like experience

802.11u and You

An emerging protocol, 802.11u, automates what is now a cumbersome and tedious process for users trying to connect to wi-fi networks and services. Completed by the 802.11u task group in mid-2010 and approved by the IEEE for publication in February 2011, 802.11u was developed to effectively automate how wi-fi devices connect to available wi-fi networks.

The MAC-layer enhancement assists the advertising of and connection to remote services by providing information to client devices about the external networks which are accessible via a particular hotspot prior to association. 802.11u enables wi-fi hotspots to advertise their capabilities and then allows devices to connect to them automatically rather than requiring the end-user to manually select an SSID. Within the 802.11u specification, the primary interworking functions covered include:

  • Network Discovery and Selection: the automatic discovery of suitable networks through the advertisement of access network type, roaming consortium support and venue information (implemented as part of HS 2.0).
  • Quality of Service Mapping: This provides a mapping between differentiated services code point (DSCP) markers to over-the-air layer 2 priority on a per-device basis thereby facilitating end-to-end quality of service. (Not implemented as part of HS 2.0)
  • Emergency Services: Emergency call and network alert support at link level (not implemented as part of HS 2.0).


Today without HS 2.0/802.11u

Tomorrow with HS 2.0/802.11u

▪       Connecting to wi-fi hotspot is completely manual

▪    Device and network negotiate capabilities

▪       Login process tedious, error prone

▪    Device auto selects best wi-fi network

▪       No consistent roaming between networks

▪    Users do nothing

▪       Many steps to gain Internet access

▪    Policies pushed to phone

▪       Difficult to connect to Web portal with phones

▪    New revenue source for carriers

▪       Carriers lose opportunity for their roaming polices to affect network selection

▪    Carriers gain opportunity for their roaming polices to affect network selection


What Happens When?

When a mobile device user with an 802.11u-capable device comes into radio range of one or more hotpots, it receives the beacons of the access points (APs). If the APs support 802.11u, these beacons will indicate support for the protocol. 802.11u uses a generic advertisement service (GAS) to provide layer 2 transport of the advertisement protocol's frame between a mobile device and a server in the network prior to authentication.


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