Research On Qos-Based Routing In SUPANET

The general background of this thesis is the research work on an NGI architecture called SUPA (Single-layer User-data switching Platform Architecture) proposed at SC-Netcom Lab (Sichuan Network Communication Technology Key Laboratory). With out-of-band signaling concept, the User-data-switching platform (U-platform) is separated from that for control and management information (S&M-platforms) in SUPA. The primary goal of first stage development of SUPANET is to focus on a high-speed switching substrate and establish a QoS provisioning framework both in S&M-platform and in U-platform. High-speed switching in SUPA is attempted by introduction of EPFTS (Ethernet-oriented Physical Frame Timeslot Switching) to merge framing, switching, channel multiplexing, and transmission functions into a single layer. QoS system in SUPA involves QoS negotiation, QoS-based routing, Call Admission Control (CAC), traffic engineering algorithms in S&M-platform, and QoS-based UAC (User-data Admission Control), scheduling and switching arbitration mechanisms in U-platform. This dissertation is dedicated to QoS-based routing strategy and algorithms in SUPANET.Routing in Internet is fulfilled by collecting and exchanging routing information through routing protocols and by constructing or updating routing table according to routing strategies. Looking up routing tables is carried out whenever an IP message arrives at a router. Construction of routing tables in advance is essential for connectionless IP routing since looking-up operation has to be carried out for each IP. However, routing table "space-explosion" may take place for routers over DWDM, since items corresponding to individual lambda with different QoS requirements can be very large. The novelty of this dissertation lies in a new QoS-based Lambda Routing (QoSLRP) Policy, which combines lambda routing with QoS negotiation mechanism. Time delay caused by QoS negotiation in establishment of an optimal end-to-end path is tolerable for connection-oriented service in SUPANET, since it needs to be done once only in connection establishment phase. The QoSLRP policy essentially is a two-step routing approach, namely: a) to choose a port-path with the least hops in advance, and b) to select the best lambda-path through QoSLRP algorithms during QoS Negotiation phase. Apart from being capable of satisfying QoS requirements for different data streams, the QoSLRP policy can also provide better balance among lambdas in the same fiber.Three algorithms have been proposed and preliminary analysis and comparison are also provided in this dissertation. To further validate the QoSLRP policy and relevant algorithms together with QoSNP, simulation experiments by use of OPNET Modeler have been carried out. Twice Single-Direction Negotiation (TSDN) protocol was exercised for simplicity with two algorithms. Simulation results have shown that QoSLRP are workable in the EPFTS environment and the connection efficiency of algorithm 2 is better than algorithm 1.