This paper proposes an efficient end-to-end QoS supporting mechanism in Next Generation Network (NGN) with heterogeneous QoS capability to support ubiquitous and distributed applications. To address this, there should be proper admission control mechanism and adaptive provisioning to sustain end-to-end QoS and maximize network utilization. Resource and Admission Control Subsystem of NGN has unique feature of centralized network resource control rather than other network control protocol system in IP network. By showing optimal flows in heterogeneous QoS capability network, NGN can support average delay of end-to-end which the applications could receive proper Quality of Service over network.