Research On QoS Based Network Admission Control Policy In SUPANET

With the development of DWDM techniques, the transmission capacity of a single fiber has reached Tbps. At the same time, the multimedia applications (i.e. audio and video) with high requirement of QoS are increasing in the network, while the existing Internet technology cannot meet their QoS. Therefore, Sichuan Network Communication Technology Key Laboratory, Southwest Jiaotong University defined a new network architecture called SUPA (Single physical layer User-data switching Platform Architecture). EPFTS (Ethernet-oriented Physical Frame Timeslot Switching) is the core technique for SUPA. The network using SUPA is called SUNANET.With the out-band signaling concept, there are Signaling & Management platform (S&M-platform) and User-data transfer & switching platform (U-platform) in SUPANET, in which network admission control includes Call Admission Control (CAC) over S&M-platform and User-data Admission Control (UAC) over U-platform.The emphasis of this dissertation is given to CAC over SUPANET S&M-platform. The CAC is the fist guarantee for SUPANET QoS. A new CAC policy called MPOM-CAC (Multi-Priority-and-Online-Measuring-based CAC) in SUPANET is brought out in this thesis. The MPOM-CAC is made up of four modules: priority queue assigning, FIFO priority queues, queue scheduling, Call Admission Controller. In order to enhance the CAC, a dynamic duple sliding windows measure mechanism is proposed in this thesis to improve the existing mechanism, which can reflect the bandwidth history information more efficiently. Having different characters, user application data can be divided into different service priorities with different QoS reqirements in SUPANET, the CAC policy ought to pay attentions to the call requests of services with different priorities. A call request is judged according to the service's priority, the feedback from TMEP and the measuring mechanism. There are two types of priority-based CAC policy: strict priority control mechanism and quota-constraint priority control (QCPC) mechanism, and the first one would result in zero connection for low priority data, while the second one which is promoted by author can not only give the high priority to connection request of high priority data, but also prevent the low priority data from zero connection. To relieve the network congestion, the QCPC mechanism adjusts the quota values for different priority services according to the network congestion state dynamically.At last, the MPOM-CAC policy brought forward in this thesis is validated through simulation experiments.