Research and Implementation of Distributed Call System Based on Soft Switch

In order to achieve the separation of the service platform and client in the call system, unify the transmission of the voice and data, reduce the communication cost for enterprise, distributed call system model is build, core function module of the distributed call system is designed for the needs of call system status and next generation network’s establishment for enterprise based on the layered architecture of the soft switch. SIP serves as the call control protocol, and layered modularized software development idea and standard opening interface are adopted, distributed call control and development of voice transmission and other core function module is realized by Visual C++ based on the Windows Socket specification. The test platform based on the XE200 voice server of H3C is established, the software function of distributed call system is verified, and voice quality of the call system, signaling process time, compressive resistance of the system is tested by Clear Sight network analyzer. The test results show that the voice quality of the system achieves PSTN effect, signaling process time is in the range of international telecommunication union Tg114 standard, CPU occupancy rate of the system, memory occupancy rate and response time are stable, and possesses good extensibility and maintainability, which achieves the anticipated designing goal.