Design And Implementation Of Border Access Gateway Based On Soft Switch

In recent years, the global IT industry is focusing on NGN (Next Generation Network) ,the governments, the trade associations, the service providers and equipment manufactures are actively participating in research and exploration in NGN. The value of NGN system is to provide open framework and standards interfaces; it departs service from signaling proceeding, then it departs signaling proceeding from media proceeding; Soft switch which is the core of NGN is mainly used to control and management services; IP protocol is used to integrate audio with video and data in NGN; Many kinds of broadband seamless access technologies are used to achieve the access of multiple services.The fact of the current network is that, as the result of insufficient IP address resource and awful security, many enterprise networks and location networks use private IP address to access public network through NAT (network address translation) server and firewall (FW) located in the adage of these networks. Because of characteristics of audio and video protocol (such as H.323, SIP, MGCP and H.248 ), when we use IP protocol to transfer them, the control channel and media channel defined by these audio and video protocol are difficult to communicate with the public through traditional NAT/FW equipment. The second problem is H.323 and SIP protocol, as the two major call signaling protocols in IP telephone field, they are different from each other, neither compatible nor mutually contain, but will co-exist for a long time in the future. To get in NGN smoothly, the another urgent requirement is to realize the transition between H.323 and SIP. To handle with the two problems as above, a solution based on border access gateway is provided in this paper.