Third Party Call Control in IMS using Parlay Web Service Gateway

One of key factors of Next Generation Network (NGN) is opening up the capabilities of the network. Parlay Group leads the standard, so called Parlay/OSA API, to open up the networks by defining, establishing, and supporting a common industry-standard APIs. Parlay Group also specifies the Parlay Web Services API, also known as Parlay X API, which is much simpler than Parlay/OSA API to enable IT developers to use it without network expertise. One of Parlay X API is Third Party Call (TPC) API which provides simple API for the purpose of creating and managing the call by the third party. IMS was devised originally by 3GPP for mobile networks, but currently it is accepted widely as a reference model of NGN even in fixed network domains. IMS has interface called ISC to open the network capabilities. This paper overviews how Parlay X Web Services can be supported in IMS in a architectural perspective, and discusses how the third party call can be implemented in IMS using Parlay X TPC APIs.