Research And Design On OSA-GW In IMS

Open Service Architecture (OSA for short) is a service platform to deploy network service. Focusing on providing mobile communication service for customer, OSA is dedicated to separating service deployment part independently from physical network part, so as to offer a fair opportunity to third-part service providers, which can connect new service more conveniently and break the closed status of telecommunication network.The architecture of IMS service is analyzed in this paper. Besides, different mode of service is contrasted to prove that OSA has its advantages in this field. Then the principle and reference point of IMS, which are related closely to OSA, are discussed deeply.After analyzing the feature and application principle of Parlay/OSA standard, this paper evaluate the application value of Parlay in IMS system, especially for API structure, class and encapsulation defined.Based on the above researches, this paper designed OSA Gateway Control System on both gateway side and SCS side, then defined controlling process of OSA-SCS calling controller, including calling originating and terminating.For the mapping mechanism between Parlay API and SIP protocol, which is the key of system, this paper pay much attention on analyzing principle, describing mapping procedure, designing mapping plot on both originating and terminating mode, defining interfaces between SIP and Parlay API, and finally implement the Parlay GCCS system.