 As a first step, we are now going to look at the technology evolution that take that took place across a wide range of basic physical networks. Let's start with fixed broadband internet access technologies. In this module, we are first going to appreciate how the technology evolution take took place from being basic service provider to the internet IP based service providers. And then we'd see what were the driving forces or we can call them the drivers that led to the realization of NGN as the convergence. First, we look at the technology evolution. Initially, the PSTNs were all about voice. They were analog networks. Then we saw the exchange to be digitized and then we slowly also saw the digital local loop right till the customer premises. The residential internet was created as a consequent need of internet and it was thought that the twisted pairs with some additional hardware could provide that internet connectivity to the home subscribers in addition to the voice. So in the customer premises DSL modems were installed and in the exchange the DSLAMs were installed. So through this additional hardware, we saw the technology moving from pure voice to voice plus data that is the internet. Then we also saw the cable TV network to be purely analog then digital and then through the docs architecture that came from the packet from the cable labs to provide internet. Now using this cable technology for internet has resulted into the widespread use of the underground coaxial cable that was only being used for providing the cable TV services that is the broadcast television and radio. Then from the old days of microwave point to point links, we saw that using fixed wireless on Wi-Fi point to point internet was provided through wireless to the remote areas. So we see that in fixed environments, we have the DSL, the cable TV and the Wi-Fi point to point. All these have resulted into one fundamental phenomenon that is an immense competition. So the traditional telecom providers which were meant to provide voice as a service, they really felt under a great deal of pressure. Why? Because the mobile networks started to offer internet as in 2.5G, 3G and more and of course the cable TV network is already there which is providing internet through the cable modems. It means that with this competition there is now a requirement to rehash and reconsider what additional modifications should be done to these networks so that they are able to stay viable in the market. The resulting drivers specifically for fixed broadband internet, we can summarize them as number one, internet itself because when everything starts moving to IP, it means that now there is no comeback. Once things move to IP, it means that the IP is going to be now the common underlying protocol for all these services regardless of which basic access technology they belong to. So it means when everything is going to be IP compliant, this is going to be the key factor in NGN. Then another thing that has also contributed significantly to the evolution of NGN is the availability of broadband both for residential subscribers as well as for corporate users. Initially the broadband was considered to be 128Kbps, 24-7 availability but now it is easily available at the rates of 10Mbps or more both for residential users as well as for corporate customers. Now this is the current change and the contribution from the fixed broadband internet technologies.