Trunking of TDM and narrowband services over IP networks

The recent interest in IP as the vehicle for transporting TDM and narrowband services stems from the possibility of using a common transport network for voice, video, and data, and the flexibility with which new services can be introduced. A key step in the evolution of networks towards a 'broadband' IP-based environment is the 'graceful' interworking of the IP networks with the existing networks and services, particularly with the circuit switched telephone network. A 'graceful' interworking approach is one whose complexity is minimal and preserves the user's perceived quality of service (QoS). To interwork with a circuit switched network whose services are pre-dominantly time-sensitive, the IP network must essentially behave as a transparent 'link' in the end-to-end connection. This paper presents an overview of the main technical problems to be addressed when trunking TDM and narrowband services over IP networks.