| Since the first IP phone (VoIP), namely Internet Phone, was developed by anIsraeli company (Vocal Tec) in1995, VoIP has been a research hotspot and widelyused at home and abroad. VoIP takes the IP packet switched network as itstransmission platform which can transfer the voice signal by the connectionless UDPprotocol based on packet compression, packaging and other special treatments. VoIPtechnology has greatly improved the utilization of bandwidth and reduced the cost ofvoice transmission.This thesis firstly introduced the development, the current application state andthe future trends of VoIP technologies. And then the basic principle and commonprotocols of VoIP is briefly analyzed. The VoIP technology is studied from threeaspects, namely system design, hardware architecture and software architecture. Onthe basis of the analysis of the drawbacks of traditional PSTN and the feasibility ofusing VoIP in Tianjin Life Intranet, a practical enterprise level VoIP scheme isproposed which integrated the enterprise data network with PSTN. The thesis made adetailed study on the problems issuing in the project implementation. The thesisfocuses on the following problems:Analyze and design the reliable backup scheme for the main and alternate centergatekeepers;Built the city level VoIP virtual network based on reticular routingsdual topology;Transfer the voice transparently on the PSTN and getting it off at any export ofPSTN;Use polling technology to enable any outside call;Construct the network management and the conference call system;Optimize the routing of voice calls;Other key technical problemsThis project has designed and integrated the Intranet with the traditionaltelephone network, and discussed the advantage of VoIP technology and its greateconomic benefits for business and individual. The project has been implementedwhich verified the correctness and feasibility of the scheme proposed in the thesis. |
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