Measurement-Based Admission Control at Edge Routers

It is very important to allocate and manage resources for multimedia traffic flows with real-time performance requirements in order to guarantee quality of service (QoS). In this paper, we develop a scalable architecture and an algorithm for admission control of real-time flows. Since individual management of each traffic flow on each transit router can cause a fundamental scalability problem in both data and control planes, we consider that each flow is classified at the ingress router and data traffic is aggregated according to the class inside the core network as in a DiffServ framework. In our approach, admission decision is made for each flow at the edge (ingress) routers, but it is scalable because per-flow states are not maintained and the admission algorithm is simple. In the proposed admission control scheme, an admissible bandwidth, which is defined as the maximum rate of a flow that can be accommodated additionally while satisfying the delay performance requirements for both existing and new flows, is calculated based on the available bandwidth measured by edge routers. The admissible bandwidth is a threshold for admission control, and thus, it is very important to accurately estimate the admissible bandwidth. The performance of the proposed algorithm is evaluated by taking a set of simulation experiments using bursty traffic flows.