Design and Implementation of a Charging and Accounting Architecture for QoS-differentiated VPN Services to Mobile Users

摘要

In the emerging context of mobile Internet, the importance of VPN services is rapidly increasing. Provision of this service is among the subjects of IST project INTERNODE. Besides the necessary technical means, charging and accounting also are key related issues, and constitute the subject of this paper. Only by dealing successfully with charging and accounting, VPN providers can recover their provision costs, increase their profits, and provide the right incentives to their users, thus leading to efficient operation of their network. In this paper, we first study the chargeable characteristics of QoS-differentiated VPN services offered to mobile users w.r.t. transport, security and mobility. Then, we define a complete charging scheme that is fair for the users and provides them with the incentives to use only the resources they really need. This scheme is based on the time-volume charging approach by Kelly; the adoption of this approach is justified in detail in the paper. We then show how the contributing providers can share the total charge earned by each VPN service instance in a fair way, with each provider collecting the portion of charge that corresponds to the consumption of his own resources for the service. This is also a very important issue for the commercial viability of VPN services to mobile users, given that its provision spans multiple domains. Finally, we specify an appropriate charging and accounting architecture pertaining to the specified charging scheme for VPN, to the mechanism for revenue sharing, and to the technical implementation of the VPN services studied. This architecture is compliant to the relevant standards and can serve as a basis for applying other charging schemes as well.