Extending SIP to support payments in a generic way.

The growth of users connected to the Internet with a high bandwidth connection hasfavored the increase of multimedia services. As many of these services are provided by means of SIP, adding support for payment to SIP might benefit vendors. Payments in SIP have been proposed for accessing services, for microbilling and even as a solution to SPAM in VoIP systems. Current proposals have some limitations such as either not being suitable for low payments or micropayments, or not supporting the use of different payment protocols or the payment is always made for the whole session or they do not take into account that streams of different quality could have different prices. In response to these limitations, we propose a new SIP extension for supporting any kind of payments (both micropayments and macropayments) on SIP. In addition to being payment-independent, our proposal solves interoperability problems. Our proposal is based in an standard extension of SDP and SIP in order to maximize the compatibility. This facilitates the deployment of payment in SIP-based services. Moreover, our SIP extension supports an offer/answer model that allows the choice of the quality of the streams as well as the payment options to use. Furthermore, it is flexible and not only supports payment but also more complex business models such as loyalty models, credentials and subscriptions. In this paper, we provide a generic way to incorporate new payment methods and business models in the vendor's software. Using some application scenarios, we make a comparison between our proposal and previous work to show some of the advantages of using our proposal.