802.11u is an extension to the Ethernet standard to make it easier for mobile devices to connect to Wi-Fi services. Generally the street calls this Hotspot 2.0. The main idea is to help provide more cellular offloading.
Generally 802.11u assumes that the user already has an existing internet arrangement. As an example the local cable ISP has installed upwards of 50,000 Wi-Fi boxes in most public areas.
Its possible to also have enrollment for users who are not preauthorized. From a user perspective, the aim is to improve the experience of a traveling user who turns on a laptop in a hotel many miles from home. This is more or less similar to the public Wi-Fi which are widely offered with coffee shops etc but targeted to hotels etc.
GENERIC ACCESS NETWORK
The idea here is to support voice, data and multimedia over Wi-Fi type connections. When cellular coverage is poor and Wi-Fi is available, then a VOIP solution is possible etc. The latest generation system is named Wi-Fi Calling by a number of handset manufacturers, including Apple and Samsung, a move that is being mirrored by carriers like T-Mobile US. The system is essentially invisible to the network as a whole.
Subscribers must upgrade to Wi-Fi/UMA enabled handsets to take advantage of the service. The iPhone 5C and above and Android 5 and above. The most recent handsets will increasingly support 802.11u to provide a more seamless experience between cellular and Ethernet based connectivity.
Windows 10 has full support for Hotspot 2.0 for mobile user.