WISPr in practical deployment

WISPr stands for Wireless Internet Service Provider Roaming is a draft protocol submitted to the WiFi alliance allowing for hotspot service. Typical WISPr based implementations deliver several features such as below

- Universal Authentication Method (or UAM, browser based login at a captive portal)
- Walled Garden
- Time based user session control
- Additional RADIUS attribute for some hotspot service settings

Some of the Jargons associated with the mechanism are:

UAM - Universal Authentication Method allows user to login to access WISP services with just a wifi network interface and users device browser

UAM Login URL - the url that is served by the provider for users to login

UAM logout URL - The url that is served by the provider for users to logout

Walled Garden : The purpose of walled garden is to let unauthenticated users to access certain page such as hotel login page, online registration form, without needing to login first.

Typical flow on a WISP enabled hotspot is something like below

1. Hotspot Client associates with a Hotspot WLAN which is typically encrypted

2. The hotspot user then tries to browse the web on the hotspot client by going to www.google.com 

3. The hotspot user is then redirected to the login portal server by the Zone director implementation. 

4. after the user inputs the credentials, the information is then sent to the UAM server on the ZoneDirector (1), the zone director is then sends the access request to the RADIUS server (2) which then responds back with accept or reject message (3).

5. After the user is authenticated, he will be redirected to the original web page they requested. Optionally, administrators can redirect them to another appropriate web page (such as an airport welcome page for example.)

References:

http://c541678.r78.cf2.rackcdn.com/appnotes/appnote-wispr.pdf