Research And Implementation Of Voice Instant Messaging System Based On Win32

This paper design and complete the Voice Instant Messaging System based on the detailed study of the techniques of VoIP, peer-to-peer network, NAT traversal, and Win32 programming.As for VoIP, by analyzing the history and basic processing procedure, we identify the key of improving voice quality. According to the traits of Win32, this paper develops Self-Adaptive Jitter-Buffer and Redundancy Smoothing Strategy which aims at achieving better performance than currently popular Skype under relatively worse network environment.As for peer-to-peer network, this paper analyzes the models of resource-tracking of peer-to-peer network. According to the demand of current system, a new Integration Model that combines Central Directory Model and Hash Ring Mass Structure is designed on the basis of study of the four types of resource-tracking system. After preliminary estimation, the model can run on most computers under the normal network condition.As for traversing NAT technique, after analyze four different NAT packet processing strategies, an effective identifying scheme is designed. And then according to different communication types of respective network, the integrated traverse program is designed and implemented. The success of experiment shows that the program can be efficient for mutual communication between nodes in different network.For Win32 programming technique, in order to improve the efficiency of the program, this paper introduces three kinds of processing methods including the thread pool, network interface, and audio interface are used in the Win32. Based on the traits of Win32, more effective treatment methods are identified. Compared with the traditional way, many treatments have been considerably improved such as Network Packet processing, audio processing, etc. after researched more efficient processing computing methods.After conducting above-mentioned studies, an overall framework of the system PPTalk is designed in this paper. Also, this paper introduces development planning of the system. According to the planning, the system has been put into trial operation at present.