Comparative Analysis Between Soft Switch System And IMS System

Soft-switch technology (SS) and IP multimedia Subsystem technology (IMS), two main technologies based on new package-switched network, have their own advantages and disadvantages. This paper comparatively analyzes the difference of these two technologies from the view of the terminal device research and development.The paper compares SS and IMS in four different aspects, including network architectures, trends in the evolution of the network, network protocols and service implementations.In the first section, the paper analyzes the network layers and the architectures of these two systems. Since SS and IMS share many technique similarities, they are very similar in network divisions. However, their network architectures are quite different. SS system is more flexible for a hybrid network with PSTN network and other traditional networks, while IMS system is more suitable for building a new separate network rather than upgrading an existing network.Secondly, this paper compares the signaling protocols of these two technologies. There are a variety of signaling protocols for SS system, with many different characteristics to meet different demands of network. IMS system chooses the SIP as its signaling protocol, and extends many SIP extensions for the applications of mobile network. It is possible to interwork between IMS system and the SIP signaling softswitch system. However, supported SIP extensions between these two systems vary and signaling flows of the detailed services are different to some extend, which are the major risks of interworking.In addition, the media protocols and transfer protocols have no significant difference between two technologies. How choosing the media protocols and the transfer protocols mainly depend on the application network is fixed or mobile.Thirdly, this paper analyzes the implementation of the most common services for these two networks. Softswitch system focuses on the traditional voice services and supplementary telephone services, while IMS system on the emerging multi-media communication services. As the same services, the main difference between SS system and IMS system is supporting ability in signaling extensions.Finally, the trends of the network are discussed throughout the paper. Comparisons between network architectures, network protocols and service implementation show that two systems still have limitations in application. SS needs a more specific architecture for network planning and enhancement capability for supporting mobile networks. IMS should optimize and simplify the technical details for application in fixed-line networks.Based on the analysis above, the paper comes a conclusion that there is a possibility to implement a compatible terminal used smoothly in these two different networks. This paper hereby states how to implement an integrated access devices (IAD) function inside Cambridge Industries Group GPON ONT product, which can smoothly compatible to the two networks. This paper describes how to achieve the design of the compatible terminal device and how to find and resolve the issues found in the interworking test with a variety of SS and IMS systems, and thereby proves the analysis of the difference between SS and IMS and the possibility to implement the compatible terminal device.All in all, this paper comprehensively summarizes the differences between SS and IMS through theoretical analysis, and verifies this analysis by implementing the smoothly compatible IAD terminal device. Through practices, this paper solves some compatibility problems with SS and IMS, which provide some hints for the innovation and confluence of the two technologies, SS and IMS.