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dc.contributorMulti-disciplinary Studiesen_US
dc.contributorDepartment of Electronic and Information Engineeringen_US
dc.creatorCheung, Cheuk-man-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/1407-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic University-
dc.rightsAll rights reserveden_US
dc.titleVoice over IP for a corporate networken_US
dcterms.abstractIn this dissertation, we studied theoretical aspects of Voice over IP (VoIP); we investigated and evaluated different types of theoretical quality of service (QoS) tools for VoIP. We also tried to integrate various kinds of QoS tools to optimize the VoIP performance in a corporate environment. We found that several tools must be utilized in order to provide an environment that can insure voice quality over a corporate data network. These tools, classification, queuing and network provisioning, should be used in every portion of the network. When applying over the low bandwidths and slow link speeds of a Wide Area Network, several additional QoS tools must also be utilized such as Link Fragmentation and Interleave, Compressed RTP and Voice Activity Detection. By a real world VoIP implementation, designing and building a corporate network for data and voice traffic, we evaluated and finally integrated various types of QoS tools to optimize VoIP performance in a corporate environment. A private VoIP network which can provide high quality of voice as well as data services was finally built, the total one-way end-to-end delay was found to be 65ms in this corporate VoIP network, for some public VoIP networks; the one-way end-to-end delay can vary significantly and frequently be higher than 300ms (ITU max acceptable international call delay), as internet routers forward VoIP packets only by best-effort service model which is mainly based on First-In-First-Out (FIFO). This private VoIP network not only meets the ITU l50ms one-way end-to-end requirements, but also perform nearly 5 times better than some public VoIP networks (by assuming that ISP can constantly provide a maximum 300ms end-to-end delay to meet the minimum ITU requirement) as the total end-to-end delay is only 21.6 percent of those public VoIP networks. Therefore, high quality VoIP has been proven to be flexible in a corporate environment with properly handling of traffic in different parts of the network by suitable QoS techniques.en_US
dcterms.extent140 leaves : ill. ; 30 cmen_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued2001en_US
dcterms.educationalLevelAll Masteren_US
dcterms.educationalLevelM.Sc.en_US
dcterms.LCSHTCP/IP (Computer network protocol)en_US
dcterms.LCSHDigital telephone systemsen_US
dcterms.LCSHInternet telephonyen_US
dcterms.LCSHComputer network protocolsen_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.accessRightsrestricted accessen_US

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Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/1407