Resource and Admission Control in NGN

After the separation of service control from transport function in the Next Generation Network (NGN), a concept of the Resource and Admission Control (RAC) was introduced to ensure the Quality of Service (QoS). It hides the details of transport network to the service layer to support the separation of service control from transport function. It detects the resource status of transport network to secure a correct and reasonable usage of transport network resources. This accordingly ensures there are sufficient resources available to guarentee the appropriate level of QoS and avoid bandwidth and service stealing. The functional architecture, the entity involved and reference point, the access type and terminal, the resource control mode, the selection mechanism between functional entities, the interconnection between different domains, and the interaction between other transport control functions are the core study content of RAC. The RACS of the Telecoms & Internet Converged Services & Protocols for Advanced Networks (TISPAN) and the Resource and Admission Control Function (RACF) of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) differ in research focus. Consequently, the unification of Architecture, defined by different organizations, becomes the central issue of future research for each organization.