This paper demonstrates an implemented bandwidth management system for the QoS-assured network architecture. To provide a cost-effective priority service, service providers should utilize the bandwidth in the existing core network. Therefore, the system dynamically optimizes the resource allocation at the edge of the network considering current bandwidth usage along the path in the core network. In this paper, the capability to estimate the usage of the bandwidth in the core network by IP flow analysis for dynamic network reconfiguration, performance to utilize the bandwidth in the core network, and scalability to process hundreds of IP flows assumed as video streaming are evaluated. Throughout the evaluations, the necessity of bandwidth management is indicated.