Design And Implementation Of VoIP Communication Over IPv6 Network

Voice over IP(VoIP) technology is developed for voice transmission over Internet. As a substitute for conventional communication method based on PSTN , this technology are becoming more and more widely used with the Intenet developing and popular. VoIP is generally based upon IPv4 network. However IPv4 address space is going worn out. IPv6 technology is being built as a solution for this problem. It can be predictable that future networks are constructed over IPv6. From IPv4 to IPv6, not only basic network layer devices such as router and network layer protocols of hosts need updates, but protocols of each layer upon network layer and applications must be upgraded to adapt to the new network environment. VoIP system integrates (internet) application layer protocols, audio(video) capture and replay, encode/decode process, so the network part needs to be changed to adapt to IPv6 environment. The achitecture of VoIP system over IPv6 network is to be researched in this paper. The structure of its hardware and software is to be analyzed and compared with what under IPv4 environment. We will discuss how to upgrade VoIP from IPv4 network to IPv6 network.Research work is done in this paper as follows:First, the characteristics of new protocol IPv6 and its system are discussed, and the patrs of VoIP system are researched. The former is discussed upon three main aspects: addressing structure, header format and route. As to the latter, H.323 standard is researched as the current main VoIP technology. Advantages of H.323 are presented; And four main components are discussed: terminal, gateway, gatekeeper and multipoint controlling unit (MCU); The components of H.323 protocol are analysed, among which H.225 signalling protocol, H.245 multimedia controlling protocol and RTP/RTCP trasmission protocol are emphasized, which are refered when we rebuild the H.323 software; The five stages of calling process are researched one by one then. One of H.323 software that is researched and OpenH323 are divided into several function modules, among which RAS and H.225 modules are researched.Next, based on the open-source VoIP software OpenH323, the task to rebuild multi-protocol (IPv6/IPv4) VoIP communication software is accomplished. We discovered how to rewrite net-communication applications over IPv4 into over multi-protocols ie. IPv6/IPv4, what is multi-protocol Winsock designing method. Based on this method and having resolved OpenH323 source into detail, the source has been...