VoIP interoperation with KT-NGN

KT has started NGN implementation by replacement of old switching system that have no No.7 signaling and caller identification functions with Access gateway. While, KT-VoIP service of H323 and SIP based protocols has been developed with many attractive services, but actual interoperation between NGN and VoIP network will be started mid. of 2004 at the second stage of NGN. KT needs to have specific implementation plan for interoperation between NGN and VoIP network and should consider many issues as certification, charging, security, numbering, routing and sewer operation. Here, certification and charging issues are mentioned and overall service now of VoIP and NGN after second stage of KT-NGN is shown.