 Let us look at some example services which service overlay networks may offer. For that we have to convince ourselves about the need which emerges and justifies the deployment of SONs and then we look at the services themselves. So the first and most important thing is that although we do have the service stratum and the transport stratum and end user applications can directly engage with the NGN service stratum and use the entire NGN infrastructure. It is very much possible. But at the same time the kind of evolution and the kind of continuous improvement which is taking place in the service sector means that the services are going to emerge at a very fast rate. So it means that there should be a mechanism that allows the NGN to be used by the service providers these services and these services are provisioned to the end users in the most seamless manner. So that is actually primary motive for the adoption of SONs. We have certain examples that we are going to look at including the classical example for NGN that is IP based TV that is stored or streaming TV service. Then we have certain community based services. We have the virtualization of home network and cloud computing. So all these are very interesting and fascinating ideas. Let's start with IP TV first. IP TV is one of the most quoted and one of the most important concerns for the adoption of NGN and for benchmarking the performance of NGNs. So IP TV services are offered in a variety of ways. For instance it could be NGN or non-NGN based IP TV service provisioning. Within NGN it could again be IP multimedia subsystem based IP TV service provisioning or non-IMS based. So we can say that there are a variety of alternatives, options, choices which could include different kinds of IP TV content. It is coming from the non-Telco or non-NGN provider network for instance a third party. In that case it becomes important to come up with a SON kind of mechanism for IP TV service provisioning. There could be for instance a customer oriented IP TV that is an IP television function which is provided by a certain community as a podcast so they can offer it as a SON based service. If IP TV has to be provided then some of the most important considerations that IP TV has to expect from SON is the session control because in multimedia traffic managing a session is quite of a concern especially once a device like a handheld PD or a smartphone is on the move, security has to be ensured and then the service has to be provided amongst a certain community. It could be a closed user group for instance a multicast group of some specific content interested people for instance students or a business community or a professors. Then SON in turn expects the service control functions to be invoked so that a user actually can interact with the application and in turn with SON services for personalization and for other kinds of modification to the choices. Let's look at certain community services. These community services could be custom services which have a particular audience. It is basically a data service which is offered to a group of people who form a logical group so they actually come up with a head or a master who decides what is going to be the QS requirement, what is going to be the security requirement and all these things have to be defined for a certain session. So these users could be non-contiguous, non-neighbor network-based individuals who are coming from home networks or customer premises networks for instance head offices or the branch offices of an organization or even could be coming from the public access networks like Wi-Fi hotspots, Bluetooth hotspots or even LTE-based networks. So it means that all these different users have to be provided IPTV service or any other community service in a very seamless manner. So this is exactly where SONs become relevant. Then we have virtual home network. So let's look at what is a home network. A home network basically is like your Wi-Fi access point-based network in your own house where you and your family members connect and get the internet services. Even you can form your own private network where you can interact or play games with your family on wireless LAN. So it is a typical home network. But you can create something similar to a home network as a virtual network by connecting again the physically non-contiguous devices into a logical interconnect. So these could be from altogether different locations. So once a home network is formed virtually then the participants or the users of that particular home network can share data services and common interests. The last one is again very hot and trendy these days. It has become more of a buzzword. But the underlying concept is very much related to SONs that is cloud computing. Cloud computing is essentially a distributed computing environment where basic computing functionalities for instance storage, processing, different applications like office applications are offered to a number of users in fact a very large number of end users who are connecting to the NGN through their own desktops, laptops, smart phones, etc. For as long as they have IP connectivity and as long as they are connected to NGN they are very much in a position to avail this cloud computing service on the basis of SON connectivity. Now these services are offered like typical client server architecture like web server where a client browser requests content from the web server. The beauty of us having service overlay network between the user applications asking any of these cloud computing service and the underlying NGN architecture is that SON provides complete transparency in fact complete independence from the underlying infrastructure so which particular software is providing the service where is the hardware situated who exactly is providing the service the network administrator or the owner of that particular service provider it is the beauty and essentially it is not much different from how typical web based services and applications work so from SON if such cloud computing services have to be offered to users what are the expectations. The expectations are that some kind of contract should take place like service level agreement then security configurations have to be reconciled and agreed to then services have to be provisioned if certain applications have to integrate certain services like infrastructure as a service software as a service or any other kind of service like platform as a service then all these have to be integrated and over time depending upon the user requirements and user subscription these have to be adopted and adopted so this is essentially what cloud computing is as a SON service based application.