Design Of User Agent For SIP-Based VoIP Gateway

In recent years, the field of VoIP-related applications is increasing and wide spreading. The VoIP services business has been continuously enriched and developed. As one kind of end-user's network access devices, the VoIP gateway play a very important role for the development and promotion of a variety of VoIP business to meet growing end-user demand for rich Web applications.In all kinds of network services agreement, SIP is most ease of flexibility, organization and expansion of various characteristics such as customer service features. It is gained by more and more network service providers of all ages.We designed and developed this SIP protocol VoIP gateway equipment to adapt to the requirements of business development to meet the different types of VoIP users need to access services, provide more performance and more scalable access services to meet different international and domestic customer demand.The design of protocol-based VoIP gateway SIP user agent (Hereinafter referred to as: UA) as the center of this paper. A comprehensive analysis of VoIP gateway SIP protocol at the application of the principles and characteristics has be done. Complete architecture VoIP gateway based on the SIP protocol has proposed. And we focused on a specific part of the UA design.Products based on our experiences and lessons of the past, the UA analysis and design of exploration and research. The UA is divided into two main parts, the UA APP and the UA Core. The two parts linked intimately and both are independent of each other's level. In accordance with the concept of object-oriented design, the UA is divided into four core modules, the call management module, the Tcid management module, the session management module and the dialog management. And around these core modules and business processes gateway system, start the design.In order to protect the system in an efficient and stable conditions, designed to meet the normative UA, flexibility and scalability of the high degree of unity.This SIP protocol VoIP gateway equipment uses the TI (Texas Instruments) latest 2510 chipset and solutions, choose the embedded Linux platform.In the design process, learn from the previous application at home and abroad different experiences and lessons. To ensure that the system at high efficiency, stability and a well regulated under the premise of the business fully into account the actual use of the flexibility and the development of needed areas of scalability. This SIP protocol VoIP gateway is able to meet and adapt to a variety of VoIP business requirements including the IMS in 3G network.