Research Of VoIP Application Based On Dynamic QoS Control

Nowadays, with the increasing development of network technology, VoIP technology has become one of the most promising technologies, and the standardization has also been further improved. VoIP technologies were based on the traditional client/server model. The application of VoIP based on P2P will compensate for the shortcomings of the traditional method, which is a new attempt.However, with the rapid development of VoIP technology; its quality of service (QoS) issues becomes more prominent. The IP network supports "best effort" service, which can meet the needs when it comes to the data service which requires only the accuracy but not the real-time one. However, when it comes to the voice services and the video services, the IP network can far from guarantee the service quality. Therefore, the problem of QoS has become the most important and most complicated one.This paper studies the control methods that VoIP is applied to network-layer QoS; the main purpose is to put forward a network-layer QoS control scheme——QoS program based on closed-loop control. This thesis first introduces VoIP technology, then gives a detailed account to QoS mechanisms, and finally analyzes the implementation and characteristics of two kinds of models provided by the network layer (Integrated Services Inter-Serv and Differentiated Services Diff-Serv). The main contents and innovation of the paper are as follows:analyzing the main characteristics of the four the voice streams——ordinary IP phone, Skype, QQ, and MSN; based on the former analysis of the characteristics, various voice streams can be distinguished, and real-time recording and related analysis to the key information of the voice stream be made; and network traffic is monitored by using SNMP. Once the network congestion happens, some dynamic adjustments will be made to QoS strategy according to different situations, at the same time, as far as possible, less affect to the other applications to ensure VoIP quality of service. At the end of this article, there are a test and a performance analysis of the system, repeatedly verify the effectiveness of the QoS program. The results show that this program can guarantee the quality of VoIP service effectively.