Inter-provider AAA and Billing of VoIP Users with Token-based Method

With the increasing popularity of wireless LAN technology, providers of real-time voice over IP (VoIP) services, known as voice service providers (VSP), are asking for roaming solutions and AAA (Authentication, Authorization and Accounting) methods that allow users to use their services from any available public Internet access network. In this paper we propose an AAA and billing architecture that allows users of VSPs to have access to the Internet from wired and wireless access networks provided by both traditional carriers, such as 3G providers, and wireless local access network (WLAN) providers. We propose a token-based AAA method that allows users of VoIP services to have their VSPs as AAA and billing contact points for the access services provided by other Internet access providers (IAP). We propose an architecture in which tokens containing authentication and authorization information allow IAPs to locally verify the users' right to obtain access services based on the contracts users maintain with their VSPs. The architecture proposed does not require direct agreements and trust relationships between VSPs and IAPs, and uses a third provider, called guarantor, which provides VSPs and IAPs with accounting and billing intermediation service and validates the users' tokens with digital signatures. We provide the token-based AAA and billing method proposed with a signalling solution based on the Session Initiation Protocol (SIP), the Security Assertion Markup Language (SAML) and the Extensible Authentication Protocol (EAP).