Implementation of 3rd party call control server by SIP

摘要

VoIP service has been taken off. However, many people want to subscribe additional services such as WWW integrated VoIP service, unified messaging service and so on. In order to implement additional service, 3pcc (3rd Party Call Control) by SIP standardized in IETF is investigated. In 3pcc, call control server establishes call session between two clients. We implemented 3pcc server and showed the usefulness by applying it to multipoint call control system.