TABLE OF CONTENTS A softswitched network, like the Public Switched Telephone Network (PSTN), can be described in terms of its functions: access, switching, and transport. Where the two types of networks are decidedly different is in their architectures. The PSTN is a centralized architecture while a softswitch architecture offers a distributed architecture.
This chapter will describe the architecture for softswitch solutions, detailing the major components that comprise this new and flexible architecture. Although many of the rules of construction change drastically with the shift to a packet-switched client-server architecture, the basic functions remain the same. Much of the current architecture for softswitch networks reflects attempts to protect an investment in the legacy aspects of a network, and softswitch components bridge the legacy technology with next-generation technologies. As economic models dictate new strategies, legacy equipment will be replaced by softswitch architectures. New market entrants will have an advantage by deploying softswitch solutions from the start. Incumbents will be disrupted by an architecture that is cheaper, simpler, smaller, and more convenient to use.
Figure 3-1 illustrates the distributed architecture that is generally agreed upon as the model for softswitch networks. This model decouples the underlying packet-switching hardware from the call control, service logic, and new service creation. This distribution enables flexibility in hardware choices as well as the innovation of new services without requiring changes in the switching fabric or structure. This model also opens up the opportunities for third-party developers. The bottom layer is considered to...
