Keeping Your Coffee Hot

Check to see if there is Wi-Fi -> Select the correct SSID from the list of detected networks -> Connect to the SSID -> Jump through whatever hoops may be in place -> Get Wi-Fi Access

Now the hoops in place may be as simple as accepting some Terms and Conditions and then you are free to browse or they may be more complex and require you to answer a bunch of questions or sign up for an account etc by which time your coffee is cold… Also sometimes just picking the right SSID from the inevitable list of 1000 that appears when you are in big cities is a challenge.

802.11u aims to make life easier and give you WiFi that just works and operates seamlessly with minimal interaction.

What is Required?

For everything to work properly 802.11u support is required on both the Access Point and the client

The Access Point needs to support Hotspot 2.0. This broadcasts some additional beacons using GAS (Generic Advertising Service) which allows the client device to know that 802.11u support is present

The client device needs to support ANQP (Access Network Query Protocol) which is used to grab data from the AP e.g which services are available and requirements to use these services.

How it Works

Effectively once a device is within a range of an 802.11u enabled access point it automatically discovers which services are available and makes an informed choice as to how to proceed. There are 5 steps to this

  1. The broadcasted SSID is used to advertise all services using GAS. (Multiple services can be advertised under 1 SSID)
  2. The client device picks up these Beacons
  3. The client device issues an ANQP request to see what services are available to it from the access point
  4. The hotspot supplies the requested services list and requirements
  5. The phone then decides which service to connect to based on its configuration

The above happens extremely quickly and makes the process seamless which results in instant internet without cold coffee!

Whether you can make use of the access point or not depends a lot on your carrier and settings. For example moving forward some data tariffs will include WiFi offload access from certain AP\'s in certain locations. As time moves on this list will grow and grow. This traffic offload from the cellular networks to Wi-Fi hotspots is very useful as it frees up cellular air time which is growing more and more full of traffic as time goes on. It also allows you to take advantage of faster connectivity, and if you are lucky enough to own a wireless network in an area that has a large quantity of wireless devices passing through it, then you may be able to offer offload and charge the carriers for use of your network.

Topic
Educational