 Though we have discussed it often on that what all led to the evolution of the next generation networks, but talking specifically, each existing technology had something in progress and wanted to move to something else that has resulted into the convergence or the confluence of these services and networks which resulted in NGNs. In this module, we should start with our discussion and this discussion is going to last few modules. That is, we look at how the classical systems look like and how the changing landscape resulted into the need or specifically the drive for NGNs. The classical communication systems can always be classified into different service sectors. For instance, we had the television network, we had the cable network, we had the internet service providing network, we had the PSTNs. So each of these was running fairly in parallel. They were all providing their services to their respective users. The basic design and the optimization done in these networks was to maximize and better the user experience. For instance, in fixed telecommunication network, voice communication service was provided with some level of value addition. In parallel, we have the mobile telecommunication network which provided mobility while the telephone call was still on. Certain value addition, for instance, caller line identification or the number portability were the natural advancements within their own jurisdictions. Then we also had the cable network which is based on the coaxial cable which was primarily meant for the broadcast, television and radio services. This also resulted into the promotion of the digital television that is also available in Pakistan on the cable. And then we have always had the internet starting from the basic services such as browsing and email to certain advanced services such as voice over IP and M commerce etc. So as far as these technologies were concerned, they were doing pretty good in their own way. But somehow the landscape started to change because in the name of diversity, in the name of grabbing a larger clientele, every technology started in a way to enter into the jurisdiction and domain of the other technology. So each legacy network we say started to invest in the internet and the basic services offered on the internet, for instance the browsing, email, FTP etc. would also be offered on other technologies. For instance, we saw DSL to emerge, we saw the cable modem, the packet cable network to emerge. We saw the internet service provided on the mobile network. So you see that internet somehow emerged as a common service platform for these different kinds of networks. What happened then? When they started promoting the services on the internet, internet as a service started to dominate these networks. So as a consequence, the requirement of coming up with solutions to maximize internet as a service became the primary focus of all these different networks. Let's look at this diagram. Here we see that the evolution took place twofold. Number one, we saw the technology evolution when different networks such as the land mobile network, the switched telephone network, the broadcasting network, they all started to move to the common technology platforms. On the market side, we saw that these networks again started providing services from each other and they started diversifying their own services and also started offering internet-based services of other networks. So the natural conclusion was that the next generation networks had to evolve. In next couple of modules, we should take up individual networks and we shall see in more detail as to what all advancements and what services these networks started to offer and we are going to substantiate and build our case for NGN.