Abstract
The so-called VoIP is to replace the resources management policy of PSTN and use Internet to make a more economic phone service. VoIP has advantage at prices, functionality and mobility. Even so, there are questions, such as QoS, compatibility, complexity and security,etc. in its. Recently, the QoS and the utilization of bandwidth has be substantially improved by P2P framework and various software technologies, and such approach is also very helpful to reliability and security. But the problem of incompatibility and complexity has become more serious with using above technologies. Base on the current situation, we need a simple, flexible and portable method to solve this predicament. After studying the existing systems, this thesis introduces a new architecture. There are two main components in this architecture: the Station and the Extension. The Station must have adequate computing power and network bandwidth to join multiple VoIP networks and be responsible to maintain the connection between he and the Extension. The Extension is a simple device which only has a full-duplex soundcard and a network interface. The function of the Extension is to collect the user’s voice and to provide user interface. The voice part is separately transmit the sound received from soundcard to the Station via the network and transmit the voice received from the Station to the users via the soundcard. The function of the Station is to transmit voice to Phone Services, maintain the network of Phone Services and dispatch system messages. The voice part is separately transmit the voice received from Phone Services to the Extension via the network and transmit the voice received from the Extension to another user via Phone Services. According evaluation result, this method can really integrate many kinds of different VoIP networks, and the user can easily access its resource he needed but don’t need care about its difference. Additionally, the Extension need only small amount of resources to work and have possibility to reduce further. Then, no matter the Extension or the Station are all extensible.