 The concept of convergence, interoperability, unification is a desirable and ideal or a utopian concept. In the field of telecommunications, data communications and the internet, this desire is known as convergence. One of the dimensions of convergence is to look at the anchoring or interoperability of the mobile networks as well as the fixed networks. It is one of the recommendations of the ITUT for the next generation networks. In this module, we are going to look at the historical perspective of fixed mobile convergence. It is abbreviated most commonly as FMC. We look at the basic idea and then we look at the objectives as well. So, like it is said that concepts are not always new. This convergence of fixed and mobile is also not an absolutely new idea. Decades ago, certain initiatives had already been taken. Like in 1990s, there was a standard, I guess by Ericsson, it is known as DECT. I think it was from Ericsson or Siemens. DECT is digital enhanced cordless telecommunication system. It is actually the provision of multiple services over cordless environment, that is, over wireless environment. This was a German initiative. Then we had the unlicensed mobile access that is the unlicensed band based mobile technologies, which could be based on different vendors, different backend technologies, but are all providing interoperability. Then a theoretical concept, it may sound generic access network, that is, whatever technology it can be, wired, wireless or even hybrid, something like radio over fiber. So, it means all these technologies have been there as a technological goal for telecommunication experts, scientists and developers. Over time, all these ideas, all these small goals have converged into one. So, FMC is basically the concept of integration or convergence. Convergence actually means whatever their protocols may be, the hardware and software interfaces may be, as long as they have some kind of common endpoint, all these technologies can be converged. In the context of NGN, we know we have the transport stratum and we have the service stratum. So, transport stratum is meant to provide convergence or interoperability by using core and transport networks, which are based on some kind of similar objectives. Then we have the service stratum. Service stratum actually means that whatever services have to be provisioned, the signaling for that service has to be carried out through the NGN service stratum. There are certain network elements, functional modules that we have seen quite much in detail in our last lectures. Quite many modules ago for service stratum for providing signaling as well as the overlay networks for services. So, convergence actually means from the services perspective, same service, same application, even same content can be provided and should be provided by the heterogeneous networks if these networks are mobile or these networks are fixed. A formal definition can be, in short, the fixed mobile convergence is actually the provisioning of different services, applications to end users regardless of where they are coming from or whatever their access technology may be. So, ITUT has certain guidelines and objectives that is that it declares in the fixed mobile convergence objectives. The most important one actually is the fixed and mobile networks should be seamlessly integrated or converged. Then the services should be seamlessly provided. We've already discussed this concept in last couple of slides but we are summarizing here. Now, whatever operator that is a telecommunications service provider or an internet service provider may be, as long as it is able to provide services in an unchanged manner by using different technologies, the convergence is achievable. Then the user equipment would be mobile. Mobility has different levels like it can be only a change of wireless access point, change of base station, change of home in would be, it could be altogether an IP change, it could be a global mobility environment or situation. Whatever that may be, fixed mobile convergence requires that mobility to be supported. Then the service, whatever it is, if it is in fixed mobile convergence objectives, it means a service can be provided from anywhere at any time in the whole world regardless of what technology is used to provide that service to an end user. The last objective is quite interesting because it deals with the user identification. We know that in next generation networks, the overall diversity of addressing is evolving, is increasingly evolving. For instance, we have the URLs, URIs, we have the E.164 addressing scheme, we have the signaling scheme which is used in PSTNs, then we have IP addresses, we have SIP URIs, SIP URLs, etc. So, multiple user identifiers have to be supported and for them corresponding triple A services whether through radius or diameter have to be incorporated. So, it means that the overall vision of ITUT for fixed mobile convergence is quite thorough.