Research On Traffic Grooming Algoirthms For WDM Mesh Networks

with the explosive increase in network traffic and the emergence of high performance optical network devices, such as optical cross-connect (OXC) and optical add/drop multiplexer (OADM), wavelength division multiplexing (WDM) technology becomes the core technology of next generation backbone networks. Traffic services not only entail the strong demand for network bandwidth. Because traffic services (e.g. IP services) are uncertain and unpredictable, optical networks are required to rapidly provide high-quality multi-granularity bandwidth services and applications to users. That is to say, it is more and more urgent for optical networks to dynamically allocate bandwidth on demand. Intelligent optical network (ION) with independent control plane is introduced. Within ION, each wavelength can be operated at very high speed, e.g., OC-48, OC-192 and OC-768 (the corresponding rates are 2.5Gb/s, 10Gb/s and 40Gb/s, respectively), the bandwidth provided by the optical network is coarse granularity. However, in operational networks, there is a huge bandwidth gap between the capacity of a wavelength and the bandwidth required by low-rate traffic streams, e.g., OC-1, OC-3 and OC-12 (the corresponding rates are 51.84Mb/s, 155.52Mb/s and 622.08Mb/s, respectively). To accommodate such kind of low-rate traffic streams (or called connections) with one lightpath will lead to inefficient resource utilization. At the same time, it is impossible to establish end-to-end lightpaths for all the connection requests, due to the limits of the number of wavelengths per fiber and the number of transceivers per node. So it is necessary to investigate how to efficiently set up connections for these traffic streams. Traffic grooming, which can also be called grooming, routing and wavelength assignment (GRWA), can meet this problem. In this paper, with the control plane deploying generalized multi-protocol label switching (GMPLS), the optimization problem for intelligent optical network is studied, and the focus is traffic grooming problem in WDM mesh networks, which covers the following: static traffic grooming, dynamic traffic grooming and the survivability of grooming networks. Static traffic grooming can be used for layout design of WDM grooming network, or be used for redesign of network virtual topology after a long period. Chapter 2 studies static traffic grooming problem from two perspectives. (1) With the limits of wavelength number per fiber, a heuristic algorithm, i.e., Plane-Construction Algorithm (PCA), is proposed, which makes maximizing network throughput as the first optimal objective and minimizing end-to-end delay as the second optimal objective. Fixed routing method is used by PCA to construct wavelength service plane, and adaptive routing algorithm is used to do traffic grooming with the free resources on the virtual topology. PCA can make the network have high utilization and good throughput. (2) With the limits of the wavelength number per fiber and the transceivers' number per network node, static traffic-grooming problem with survivability (against single failure) is studied. Based on fixed-alternate routing and adaptive routing, several heuristic shared-path protection algorithms are proposed, whose objectives are to maximizing network throughout. Simulations evaluate these algorithms, and the results show that the algorithms based on maximizing resource utilization have good performance. The above-mentioned research, which has much value, can be a reference for designing WDM grooming network.In the operational networks, connection requests dynamically arrive and hold for a period, then leave. With the constraints of the number of transceivers per node, the number of wavelength per fiber and wavelength continuity in optical domain, dynamic traffic-grooming problem in WDM mesh networks is investigated in chapter 3. At first, three grooming polices are proposed, three routing graphs for traffic grooming are presented, and then three adaptive traffic-grooming algorithms, i.e., TLRA, SLRA and JRA, are proposed. Sim...