Research On Connection Admission Control Mechanism Of QoS

With the rapid development of the Internet, more and more new applications have been applied on the current network, they all require strict service guarantee in packet transmission rate, cell lost rate, delay and jitter et al, however, the network can't afford the demand at present for its transfer mode based on best-effort strategy. To resolve this, we need apply Quality of Service (QoS) to provide the service guarantee in the traditional IP network.The models of QoS framework include IntServ, DiffServ and MPLS, they provide a whole peer-to-peer resolving method. In the paper, we discuss the Connection Admission Control (CAC), which is the one of the most important key components of QoS. By comparing and analysing some common CAC mechanisms, we design a new CAC strategy combined with the characteristic of network traffic, which works in IntServ model mainly. We innovate in the following points:A dynamic sliding window measurement method. As the improvement of existing mechanism, it can adjust the length of measure window dynamicly according the result of measure, so that adapting to the change of the network traffic and increasing the link utilization.A Min-Max estimate mechanism based on the equivalent bandwidth and bound bandwidth, composed with the measurement mechanism, it controls the packet lost, guarantees the quality of service.The fairness admission decision control is the core of our CAC method. It provides the equality distribution control that still affords the high utilization. It overcomes the shortcoming of discriminating the large-bandwidth calls, also maximizes the satisfaction of system. With the VC++ tool and multithreading technique, we develop the simulation control program, which used to compare with the others, validate our design ideas. At last, we summarize the paper and give some proposals for furture research.