NGN networks: a new enabling technology or just a network integration solution?

Over the last years, developments in telecommunication technologies, bringing possibilities for rich-context communications with multimedia content, has satisfied most of users' demands about always on, rich-content communication ways with high degree of versatility (conferencing, application interactivity). On commercial level, all these new features have been integrated within the 3G UMTS, a technology which only recently has started being gradually adopted. 3GPP, the standardization body working on UMTS technology definition has so far not only described services categories, but defined consistently ways for delivering them with appropriate Quality of Service (QoS). Despite the emergence of new fixed and wireless communication technologies, like the WiFi, WiMAX and xDSL, with high bandwidth rates and seamless conformity to the IP, the capability of the new UMTS technology to delivery its services in a " measurable " way and with user-defined QoS has been identified as the main reason for the success of the new multimedia applications on the market. Wishing to further exploit users arisen awareness about new multimedia communication services and expand possibilities for new profits in the new fixed and wireless network domains, the industry of communications has set a new target, that of creating " ubiquity " in service delivery along with " seamlessness " in keeping steady the " user experience " in terms of service tariffing and QoS satisfaction. Answers to these problems has come to give the Next Generation Networks (NGN) technology, a new initiative created collectively by ITU, ETSI and 3GPP that aims at delivering all these new communication features on a " network agnostic " or otherwise called " heterogeneous networks " communication environment, where the only discriminating factors for service provisioning will be the user himself, his selected service types and the desired QoS. In this respect, the NGN technology shall not only provide a single solution for various network types integration, but must answer globally, on behalf of all communication technologies it embraces (fixed, mobile, wireless), the problems expressed earlier about providing service " ubiquity " and " seamlessness " , dealing with issues such as, zero service disruption for moving, roaming, handover users and QoS guarantee among different technology networks with diverse QoS capabilities. Over the past few years, evolution of the NGN concept along these lines has led to the definition of the first version of a " network agnostic " communication technology, the IP Multimedia Subsystem (IMS). IMS has become today …