Research On Gateway Based On Asterisk

Asterisk based on Linux operating system is one of excellent open source software in telecommunications, which implement many functions of IP PBX. Its characters of flexibility and free of charge are high in many users＇favor. Asterisk also can decrease significantly the cost of telecom operators. The aim of the paper is to propose a new approach to implement the gateway to reduce cost.In the first two parts, the paper illustrates the functions and applications of asterisk. And then it analyses several kinds of protocols related asterisk gateway. As the boundary of the two kinds of network, the main task of gateway is to transfer one protocol to another. In order to understand how asterisk implement the protocols, it describes the principle of protocols carefully.In the third part, the paper explains the detail of source codes of asterisk, such as prime data structures, data procedures, implementations of protocols and so on. Solid knowledge about the source codes helps us change or add modules to meet users＇requirements.In the fourth part, it clearly shows the detail steps of building the asterisk gateway, including SIP/ISDN PRI, SIP/ISUP,3G-324m/SIP. And the paper also analyses the performance of asterisk gateway according to tests.The final part makes a brief summary of the research work and discusses the improvable areas of the implementation, which will be the future work of the paper.