16.1 Introduction

As will be appreciated from the previous chapters in this book, it is unrealistic to expect the large-scale deployment of VoIP solutions to take place completely independently of existing networks and services. Recognising this problem, the Telecommunications and IP Harmonisation Over Networks (TIPHON) project has been created under the umbrella of the European Telecommunications Standards Institute (ETSI) with the aim of addressing service level interworking between traditional switched-circuit networks (SCNs) and the emerging next generation networks based on VoIP technology.

TIPHON's objective is to support the market for real-time telecommunications services between users, including voice and related voice-band communication, such as facsimile, over multiple network technologies. So telephony, multimedia conferencing, instant messaging and eCommerce may all be examples of applications and services within the scope of, and enabled by, TIPHON. However, it is important to recognise that the capabilities of such services may go beyond the common services provided by either basic Internet connectivity or the PSTN today.

TIPHON's principal goal is to enable users connected to IP-based networks to communicate between themselves and also with users in SCNs, especially those served by PSTN, ISDN or GSM networks. In this regard TIPHON addresses the difficult, yet extremely important, area of multi-network interworking across multiple administrative and technology domains. Since it emerged as the first and most dominant VoIP technology in the late 1990s, the initial focus of the TIPHON project has been concerned with issues relating to...