 The importance of the user mobile or user equipment is there. It's very obvious But then again the user equipment Interact with the next generation network through the customer premises equipment. We know it is a user equipment itself It can be the customer premises equipment. It could be eNode B It could be home eNode B So whatever the customer premises equipment is it has a direct impact on the overall user experience now if the user equipment or The customer premises equipment itself moves Between different service providers or the next generation network operators So to ensure that the quality of service is not compromised and it stays consistent across these networks The resource and admission control function communication is going to be very important between The engine operators. So we look at some interesting customer premises equipment mobility Situations and then we'll consider the scenarios which can be Configured to make sure that different kinds of CPE mobilities are handled smoothly So let's start the customer premises equipment mobility actually means that the flow of media between the calling party and the call party or the endpoints Has certain QS provision requirements and if it has to This media flow has to be Sent over multiple transport networks then inter operator RSCF communication becomes a requirement. So we have two users each with its own CPE would now require communication Between different operators through Their respective RSCFs. So three possible scenarios can be considered The first scenario is that there is only one CPE in in a visited network It means that the primary concern is now going to be the resource availability in the visited network and the unavailability of the Moving CPE in the home network. So both are discovery and resource allocation have to be made sure So both the CPEs the one which is moving and the one which is in the home network are going to communicate with the service control function In the home operator network, so it means this SCF service control function Invocation is going to be done at the application layer Layer 7 the service control function would now send the QS information the QS requirements or the QS profile to the home RSCF to Reserve the resources in the home network It is needed because the end-to-end connection means the home network has to provide resources Now the home RSCF communicates with the visited RSCF Let's look at it diagrammatically Here we can see that we have the home network and we have the visited network. The home network is Offering its services to two CPEs CPE1 and CPE2 Now both the CPEs are belonging to the home network. That is the first operator operator A Now if the CPE2 belonging to operator A Moves to another network that is Operator B. In that case all their Coordination is going to happen through the incorporation or Intermediation of the service control function the service control function would then contact the RSCF of the home Network which in turn would not only allocate resources itself. It would also contact the RSCF of the visited network So in this case we see that with movement of one CPE from a network the RSCFs are required to talk each other Through the intermediation of the service control function. The second scenario is when The two CPEs are located in the same visited operator It actually means that both of these are mobile. They have left their parent or home network It's not much different from the first one. The only thing different is going to be The resources are now required to be reserved in the Foreign or the visited network only so correspondingly the QS information is sent from the service control function to the To the home RSCF that is not going to reallocate the resources as such locally But it forwards the request to the visited RSCF and the resources shall now be allocated to the two CPEs in the visited Network so you see here we have the Home network for both these the CPEs these CPEs both move to the same foreign network That is operator B. Now the service control function is Going to be involved again in this case the SCF would initiate the resource allocation required for QS provisioning to the operator A the home network which in turn is Going to tell the visited network that is operator B to allocate the resources to both the CPEs Because these CPEs are going to talk to each other and then this the third scenario where the two CPEs are Visiting two different networks their initial home network is the same now that they are in two different networks So the home RSCF has to be involved to talk to two different visited RSCF So both the CPEs are now going to request this resource Allocation through the service control function in the home network the SCF would now communicate with the home RSCF Which in turn will communicate directly with the RSCFs for the visited networks for resource allocation Here you can see it's a very interesting scenario. We have One home network that is operator A for both these CPEs Somehow they move to two different networks. They still want to have their connection. They still want to have the media flow With certain QS requirements now that they are in two different Networks that is operator B and operator C The service control function would now initiate or request the RSCF of operator A to interact with RSCF of B and RSCF of C to provide resources to respective CPEs which are there in their networks