Research And Implementation Of MGCP Protocol

VoIP technology is an extremely important application in Next Generation Network (NGN). Soft switch is the kernel of NGN, and the core of NGN is "the separation of service and control; the separation of control and bearer". MGCP, used to control media gateways, conforms to it. MGCP and H.248/Megaco play an important role in the NGN.The former two chapters of this paper are focus on the VoIP-related concepts, the architecture of the soft switch and the content of MGCP.And the following three chapters are about the analysis and studies in some problems, which widely exist, in the real applications.Private Network Traversing is a common problem because of present shortage of public IP addresses. In this paper, a solution based on the translation server is presented. The principle, the work mechanism and the signal flows are described in deatail.Many people care about and study how MGCP mutually communicates with the other VoIP protocols. In this paper, a mutual communications model is presented. The formats of messages are defined. At the same time the call control flows of mutual communications between MGCP and SIP are described as an example.How to improve the quality of voice is a hot topic, and many related technologies are brought out. This paper does not try to achieve the goal by optimizing the existing network and voice encoding algorithms. First, we measure the MOS of voice on the MGCP terminals. Then the type of encoding algorithm can be changed dynamically according to MOS.In this way, we can make full use of existing network to improve the quality of voice.In the last part, Residential GateWay (RGW) defined in RFC3435 is implemented. The flow chats of main modules are presented and some problems about the implementation are described.