A VoIP communication system for advanced public networks

Abstract With recent advances in IP‐related technology, VoIP, which can provide cheaper communications than conventional telephone networks, is attracting interest. Communication within IP networks has already been established in practice. In the early stage of introduction of the technology into the public network, VoIP and conventional tele‐phony coexist, and it is important in spreading the use of VoIP that interconnection to the existing network should be achieved. Furthermore, in order to promote the shift from telephone to VoIP, the existing telephone service should be available. These functions of interconnection and the existing service are resources of the PSTN exchange system, and it is inefficient if a new VoIP system is developed without utilizing these resources. Consequently, this paper proposes an architecture for the Call Agent system in which the above functions and the VoIP function are achieved by extending the PSTN switching software. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(4): 52–60, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ecja.10229