802.11u – the one that made hotspots less dumb

IEEE Std 802.11u-2011, Amendment 17, was a game-changer for **Wi-Fi roaming and interworking**. developed by **Task Group u** and released in 2011, it didn’t mess with PHY or speed – it tackled something more subtle but just as critical: **how your device chooses and talks to external networks** before even connecting.

before 11u, Wi-Fi networks were pretty blind. your device would see an SSID, try to connect, and only then figure out if you needed a login, payment, or if you were even allowed in. 802.11u changed that by adding **interworking support** – letting clients ask questions before committing to a connection.

key to this were two protocols: **Generic Advertisement Service (GAS)** and **Access Network Query Protocol (ANQP)**. they allowed access points to advertise what kind of network they were part of (e.g. public, private, mobile operator), what services were offered, and how to access them – all before association. think of it like reading a menu before sitting down.

11u also laid the groundwork for interaction with **Subscriber Service Provider Networks (SSPN)** – letting Wi-Fi networks integrate more cleanly with mobile carriers, and supporting seamless roaming between WLAN and cellular. no more captive portals and guesswork – now devices could make **informed choices**.

this amendment got pulled into **802.11-2012**, and stuck around in 2016 and 2020. and most importantly, it became the backbone of **Hotspot 2.0 / Passpoint** – the system that lets your phone connect to trusted public Wi-Fi without you touching a thing.

802.11u didn’t make Wi-Fi faster – it made it smarter and way more user-friendly. no more connecting just to find out you can't go anywhere.