Wisper ISP, also known as WISPr (Wireless Internet Service Provider roaming), is a draft protocol initially submitted to the Wi-Fi Alliance. The purpose of WISPr is to enable users to seamlessly roam between different wireless internet service providers, similar to how cellphone users can roam between carriers. The protocol outlines best practices for user authentication using methods like 802.1X or the Universal Access Method (UAM), which involves browser-based logins at captive portal hotspots. Authentication in WISPr involves the use of a RADIUS server to authenticate the subscriber's credentials. It defines the necessary attributes for RADIUS, emphasizing the use of AAA (Authentication, Authorization, and Accounting). Additionally, for smart-clients, WISPr introduces the Smart Client to Access Gateway Interface Protocol, an XML-based protocol for authentication. This allows devices using smart-client software to log in to hotspots seamlessly without user interaction with captive portals.