As the technological scene of the 21st century changes rapidly, new facts for telecom and networks are coming to the front. Users’ growing demands for enhanced multimedia services on one hand and expanding infrastructure on the other lead to the realization of innovative networks, able to serve more subscribers more efficiently. Past technologies have failed to meet the present and immediate needs for integrated services and applications of real time traffic and high data volumes, high speed Internet, video on demand, and mobile communications everywhere and all the time (Chochliouros & Spiliopoulou, 2003). Globalization and deregulation of the market stimulate increased competition and call for integration of existing switching, optical, satellite, and wireless technologies (Commission of the European Communities, 2006). In the telecom industry new commercial opportunities are introduced. Internet and data services growth, in combination with increased maturity of packet-based technologies, results in the redrawing of traditional telecommunications architectures (Barnes, & Jackson, 2002). High quality, distributed, multiservice networks, with advanced features of flexibility and reliability, are now feasible, accommodating both circuit-switched voice and packet-switched data (Chochliouros & Spiliopoulou, 2005). This key architectural evolution in telecommunication core and access networks is described under the broad term “next generation networking (NGN).” Next generation networks, which are expected to be deployed in the markets over the next years, base their operation on packet transport of all information and services, voice, data, or multimedia. Encapsulation into packets is commonly implemented via the Internet protocol (IP), whereas services become independent of transport details, thus enabling improved functionality at the edge of the network, extreme scalability, and higher availability (European Commission, 2005). Nevertheless, the industry shift from centralized switches to “next generation” distributed, enhanced service platforms arises very important issues. Interoperability with existing networks is implicit, while great challenges appear in the conversion strategies towards implementing and exploiting the new architecture. Conventional communication systems need to evolve smoothly to NGN, through well-defined and carefully- planned transition procedures, in order for true convergence to take place.
