Abstract:As a winning approach in PSTN, IN will play an important role for IP telephony service provision. Current research efforts focus on interworking of IN and Internet via gateway. The problem of this solution is that it inherits the drawbacks of conventional IN. The main contribution of this article is to redefine the IN conceptual model and presents a distributed architecture to make it fit IP telephony platform. The possibility to enhance gatekeeper to be SSP is highlighted. To show that this solution is practical, an example of service implementation is given. Compared with traditional architecture, MA-based service architecture has many advantages in distributed control, service customization and flexibility. Besides, this approach can combine legacy systems and get a smooth evolution.