The world of telecommunications is undergoing a rapid change in designing and developing applications. Telecom operators are becoming increasingly forced to diversify the portfolio of available services to ensure customer loyalty. Indeed the operator's business has far exceeded the supply of traditional telephony to open up to the most demanding services. For this purpose IP Multimedia Subsystem (IMS) has been a major work effort of the 3GPP (3rd Generation Partnership Project) standards bodies for several years now. However, the acquisition of services by operators slows down the development of services offered because of the integration difficulties, and the quality of services issues. This has let to a new approach proposed in this paper. The idea is to set up a Service Broker (SB) able to look for the best offer of service requested to deliver it to the customer. To ensure a transparent communication between operators, customers and service providers, the NGOSS (New Generation Operations Systems and Software) Framework is used in a consistent manner.