Credit Control and Prepaid Applications Avi LiorBridgewater Systems Parviz YeganiCisco

Motivation  Prepaid Data Services are very important to Service Providers: 3GPP 3GPP2 WLAN  AAA infrastructure is central 3GPP => Diameter Credit Application (HSS) 3GPP2 => RADIUS based IS-835 C WLAN => RADIUS (WiFi Alliance)  Deployments are happening today.

Requirements  Service Portability Prepaid Data Service needs to be available anytime. At different locations. Using different access technologies.  Service Continuity Prepaid Data Service should be continuous as users roam. Between different locations. Crossing different access network boundaries. –Same or different technologies

Requirements  More requirements such as: No revenue leakage Support for multiple sessions Extensible to support different prepaid schemes Time, volume, others  Good source of requirements: Francis et al, Design Issues for Prepaid Data Service draft-francis-prepaid-00.txt

Prepaid Data Service Generic Architecture

RADIUS Implementations  Access Request includes Prepaid Capabilities of the Access Dev  Allocate initial quota during Access Accept  Request of additional quotas (between access device and prepaid system) Some are proposing Accounting messages. Accounting is for recording not control. Requires accounting to be done in real-time. –Pass-through mode vs. store and forward behavior for accounting message delivery In broad networks, we can’t guarantee the real-time delivery of accounting messages!!! Use Access Request - Access Accept We know how this performs in broad networks.  Use of Radius Dynamic Authorization [CHIBA] Disconnect Message (DM) to boot users off especially in mobile situations. Change of Filters (CoF) to restrict users access once the account is depleted -- So they can replenish their account (Spend more money)