The IP Multimedia Subsystem (IMS) has
been standardized as a Service Delivery Platform (SDP)
positioned in the control layer of the Next Generation
Network (NGN) infrastructure. To meet the diverse
demands from NGN customers, it is effective to integrate
different technologies, such as telecommunication, mobile,
and Internet to enrich offered services. To integrate these
domains the Service Oriented Architecture (SOA) concept
developed for enterprise networks, can be applied into the
IMS architecture. In this paper we overview the service
control methods in IMS, discuss the concept of using a
Service Broker (SB) to control and orchestrate service
executions, and address some main issues of the
integration of the SB component in the IMS architecture.