Routing And Performance Optimization Of Computer Networks

With the development of data service and multimedia applications, the explosivegrowth in IP traffic on the Internet is driving the demands for new high-speedtransmission technology. The best-effort service model on today's Internet cannotsupport diverse service requirements from different IP applications. Much effort hasbeen devoted to QoS provisioning in the Internet. As the key issues of the nextgeneration networks, how to guarantee quality of service (QoS) and how to realize thenetwork data exchange in high speed have attracted more and more concerns, andmany efficient routing and performance optimization methods for various networkarchitectures and diverse connect requests are designed.In this thesis, we focus on the quality of service routing in multimedia networksand routing and performance optimization in WDM optical transport networks. Themain works and innovations are as follows.1. To solve the Quality of Service (QoS) unicast routing, three efficientalgorithms are proposed. A novel precomputation algorithm based on theK-optimal paths, a novel evolutionary algorithm named QoS_EA and analgorithm based on the experimental analysis are designed for the problem.The computer simulation result shows that the proposed three algorithms areefficient and superior to the other algorithms for the problem respectively.2. A reliable multicast routing algorithm based on reliability test in multimediacommunications is proposed for the different reliability requirement of eachmulticast member. At the beginning of this algorithm, an initial multicast treeis given, and then the reliability of the path between the source and a selectedmulticast member can be calculated respectively, if the correspondingreliability requirement of this path isn't satisfied, the reliability of the pathcan be improved by modifying or changing the path according to thealgorithm.3. For the problem of routing and wavelength assignment in mesh network,especially the problem in the network that the node with different function,an algorithm based on the equivalent network is designed. Firstly, anequivalent networks model of WDM network is constructed, andwavelength-dependent equivalent arc, equivalent networks, equivalentmulticast tree and some other terms are presented. Finally, we prove the twoalgorithms are feasible and optimal for the problem respectively.4. Load-balance routing and wavelength assignment problem in WDM opticaltransport networks under the different state of links is addressed. Twoalgorithms based on the state of links are proposed for the problem, onenamed LFLSDRAW is for finding a path having the highest state levelbetween a pair of nodes in a network, and another named RLSDRAW is forfinding a path having the required state level. Both algorithms are capable ofselecting a better path to achieve load balancing and reduce the congestionprobability, and superior to the existing algorithms for the problem.5. To solve the performance optimization problem in WDM optical network, theinfluence of network design, route selection, and wavelength assignment onnetwork performance is analyzed by employing the systematology andeconomics theory, and then point out that the performance of the WDMnetwork not only depends on the algorithm for routing and wavelengthassignment but also on the network design. Furthermore, a mathematicalmodel of the performance optimization in WDM network is formulated,which is based on the network design, algorithm for routing and wavelengthassignment, network service and market price. Finally, an interactivesimulation process for the WDM network performance optimization isproposed.