 The resource and admission control function is a service provided by the next-gen network architecture to serve both the transport stratum and the service stratum, comprises certain network elements, and it has certain distributed nature. The deployment designs and options that we can have has a direct impact on the kind of services that we can get, the administrative control that we can obtain and the interoperability we can get between the policy decision and policy enforcement functional entities. We'll first understand the need to have such variety in deployment and then we'd look at the deployment architectures themselves. The modules in the RACF are basically the functional entities which perform specific tasks to realize the QoS provisioning. Now they also have a relationship between the service and transport stratum entities. The RACF performs QoS provisioning either in conjunction with the service control function or without the incorporation of the service control function. This leads to three options that can be considered as different deployment architectures. The first one is when the service control function is involved as an intermediary. The second one is the RACF performs QoS control without the intermediation of the SCF. And the third one is RACF is now common both for the access and core networks. So we'd look at the diagrams then we are going to understand them in detail. Let's look at the scenario where the resource and admission control function is performed by the intermediation of the service control function. So here we see we have the service stratum including the SCF it is being shown to you here. At the transport stratum we have the RACF. The RACFs of the core and access networks are talking to each other via SCF. It means the QoS control is actually being dictated through the involvement of the SCF. What are the pros and cons? Let's look at them. Since the access and core networks are separate domains. So as such within the RACF the policy decision functional entities of the core and the access networks are not going to communicate with each other. Only indirect communication is possible through the service control function. It actually means all the signaling which are performed for QoS control is coming via the service stratum functions. It means the application layer is spelling out its QoS functional requirements. And then the SCF is dictating the RACF to mediate between the core and access networks. The second option is when there is no mediation between the two RACFs through SCF. And these RACFs both for the access and core network are managed independently and they communicate with each other directly. It means the signaling for QoS control takes place between the two RACFs. The service control function in this case is now the scope of the core network and as such it is not communicating with the access network. That is exactly what is mentioned in here that the access and core networks are independent domains. Each domain has its own RACF. These RACFs communicate with each other correspondingly. Their PDFs are going to talk to each other and there's no involvement of SCF in intermediation as such. And then the last option is once we have a single administrative control both for the core network as well as the access network. In that case we are not going to see much involvement of SCF. In fact the RACF with single administrative control actually results into more smooth and harmonious interaction of the PDFs both for the access and core networks. Since the PDFs are part of the RACF. So as such we are not going to see two PDFs and there's just going to be one PDF. But the interesting thing is for these PDFs to implement the policies we need the Policy Enforcement Functional Entity. Now the Policy Enforcement Functional Entity actually exercises the policy or enforces the policy in relation with the Transport Radio Control Functional Entity. Now the TRCFE actually is going to be different for the access and core networks because it is dependent upon the underlying technology.