A modeling method of access network for resource reservation and admission control of NGN

NGN (Next Generation Network) is an IP (Internet Protocol)-based network that provides QoS feature using resource reservation and admission control technologies. NGN communicates with UE (User Equipment) using SIP (Session Initiation Protocol) messages bearing required resource information, such as bandwidth. RACF (Resource and Admission Control Function) in NGN uses this information to check if there are enough resources available for the communication, and to set the flow control parameter on the gateway router at the edge of the NGN core network. In order to realize this resource management and flow control, RACF needs to manage the resource usages and the routes of all the flows within the NGN, especially those in access networks. However, standard bodies, such as ITU-T and TISPAN, do not define the structure of the access networks as an operator specific matter. In this paper, we identify the requirements for the resource management within access networks, and propose a method of network modeling by introducing the concept of “virtual paths” as an abstraction of real transport links and show its adaptability to several possible structures of the access networks. We also show this modeling method is adaptable for the resource management of the network that conveys several traffics of different QoS classes.