 The importance of implementation of NGN is crucial to the successful operation of NGN services and the underlying network. For that, let's first discuss what are the principles which govern, number one, the definition and assignment of functionalities and the implementation aspects that is in terms of necessity and sufficiency a.k.a. the completeness. For that, let's look at the whole domain of defining principles. I call it the Principality of NGN. The Principality of NGN actually requires certain standards which must be met for all these functions and their implementations to be achieved. The first one is backward compatibility. It means any service, any implementation, a function that is provided in NGN must also cater for the earlier versions so that the earlier versions are able to seamlessly integrate into NGN. Openness. Openness means when a certain new technology is introduced, it is not totally alien to NGN. An NGN framework or architecture easily adopts and augments that new standard. Independence. Independence means when a certain service is to be executed or is to be provided or to be implemented, it should be done regardless of the preparedness of the other infrastructure. This helps us to prepare services and deliver them in a short while. Convergence is to make sure that a certain service is available on a broad range of diverse networks which are part of the overall NGN. Every service, every application which is provided on NGN has to be secure. The definition of security may vary from implementation to implementation or from one service to the next application. But essentially, it is one of the very important concerns. And lastly, every function that needs to be implemented has to be defined in such a manner that there is no confusion with regards to its definition, its inputs, its underlying rationale and the output. It means a function has to be a closed box with a clear input, clear output and a clear functionality. Let's quickly run down over all of these. The first one that is backward compatibility actually maps down to the support for multiple access technologies including the present and the past ones also. Both in fixed and mobile. The open service control is that the control environment should be open to different kinds of services and different kinds of service providers. An example is IMS that has been adopted by the ITUT from 3GPP Release 8. Now IMS actually has well-defined open interfaces that any service or service provider can adopt and join the NGN bandwagon. The independent service provisioning, as I mentioned, the transport and service strata are separated via open service control. The open service control helps us to develop some kind of independence in the individual implementation of transport and service strata. So that helps us to create quick services, the services which are basic but are ready to be shipped and deployed. This creates an open and a fair market of service competition, improves the overall quality over time and the overall service delivery time is also reduced. The support to integrate services in a converged network essentially implies, regardless of the type of network, the time and space of a certain user, some kind of generalized defined services should be accessible to all in a consistent manner. That is, if the qualitative service is of a certain type on one network, then it doesn't vary much on another kind of network. Security is a concern that goes more serious when a complex NGN network is realized. If it were a standalone private network, which was closed to the outside world, implementing security would have been peanuts. But with the kind of openness that NGN promotes, vulnerabilities take altogether a new level. So there is a likelihood of coming across the attacks or the threats which are unforeseen. The security solutions are required to be continuously adopted that keep up with the new design of emerging protocols and consequent threats from the bad guys. And finally, when we talked about atomicity, I actually was referring to the functional entity characteristics. That is, the entity or the smallest definable module that can be designed to provide a certain kind of functional implementation has to be incorporated into NGN. That is, the concept of entity allows the NGN to be realized in a very modular and successful manner. When we talk about entities, for instance, a router, a switch or a end server or a client application are all entities. Now these entities are essentially independent software or hardware or a combination of both these functional implementations. Now these somehow are replicated across the whole NGN, but these are not distributed. It means when we talk about the client server architecture, we have the client side entity, we have the server side entity and we have the network side entity. Now allowing the whole implementation to be entity like is really a success model.