| In order to provide Quality of Service (QoS), the network must enforce traffic management such as traffic classification, admission control, access control (shaping and policing), flow control and congestion control. Applying the policies and mechanisms of traffic management, the Internet Engineering Task Force (IETF) has proposed various QoS models, Integrated Service (IntServ), Differentiated Service (DiffServ) and Multiple Protocol Label Switching (MPLS), for the next-generation Internet in order to deliver emerging multimedia applications, which have stringent QoS requirements. It is interesting to note that the Token Bucket (TB) algorithm as a control mechanism has been employed popularly in them.; In this thesis, we construct a new dynamic model for the TB control mechanism and apply a system approach to its analysis. This model is then augmented by adding a dynamic model of a multiplexer in an access node, where the TB exercises a policing function. In the model, traffic policing, traffic multiplexing and network utilization are formally defined. Based on the model, the issues such as QoS, traffic sizing and network dimensioning are studied. And also we propose an algorithm using feedback control to improve QoS and network utilization.; Applying MPEG video traces as the input traffic to the model, the numerical computing results very much agree to the analytical model. The model gives a guideline to study the interactions among the traffics and elements of TB-based access control to achieve desired QoS and network utilization. |
