| In recent years, with the rising of high bandwidth services like IP high-definition television, high-definition video conferencing, the big data center computing and migration. We gain an explosive growth of the demand of the network bandwidth. The optical transmission network is facing the challenge of large capacity, high rate and strong burstiness. How to deeply excavate the potential of optical fiber transmission and construct a more flexible and efficient network has been widely concerned.The traditional wavelength switched optical network adopted WDM technology and achieved end-to-end connection of wavelength channel. While the new technology improved the capacity of the network to an extent, the WDM network still faces the problem of low resource efficiency. As WDM network adopted fixed spectrum grid, modulation format and signal rates, the network can’t suit the services with over100Gb/s data rate. With the development of OFDM technology and bandwidth-variable OXC devices, an innovative elastic transceiver architectures (capable of selecting their rates according to the network state by choosing the best combination among modulation format, coding rate, and spectrum width) are being investigated. The conventional legacy grid has to evolve toward finer granularities, so that an arbitrary number of smaller frequency slices (e.g.,6.25or12.5GHz [1]) can be used to create a channel serving the client demands with as many spectral resources as needed, it provided transmission with different modulation format and numerous data speed from Mb/s to Tb/s. Compared to fix-grid WDM network, slice network provide more flexibility and higher spectrum efficiency.The research work in this dissertation is supported by the national863project named "the search of gridless optical switches technology and prototype with variable rate". The paper focus on the research of survivable algorithm and resource reconfiguration problem in elastic optical network and present multiple implement solutions. The simulation of the proposed algorithms has been given and the main work of this dissertation is summarized as follows:(1). The traditional survivable algorithm in elastic optical network can’t provide protections of connections with priority. To fix this problem, we present a novel protection method which provides a grading pre-alarm scheme in both simple and complex network architecture. This method leads monitor information into protection algorithm, and set different thresholds for connections according to their priority. When the detected OSNR deteriorates to a threshold, the algorithm reserves protection bandwidth for the corresponding connections. This process provides high-priority connections shorter fixed time and higher chance of protection. What is more, when the network load becomes heavy, the method dynamically adopts spectrum compression to promote spectrum usage.(2). We analysis the inefficiency use of spectrum resources caused by dynamic build and tear of connections in elastic optical network. The effect of existing resource reconfiguration algorithm depends on the initial state of the network. In this paper, we present an after-defragmentation optimal Independent Sets based greedy defragmentation algorithm. We perform and compare the numerical simulation of the shortest-path defragmentation algorithm (SP-DA)[2], the dynamic algorithm without defragmentation (non-DA) and our proposed algorithm. To estimate the performance of the algorithms, we also proposed a characterization parameter called the spectrum continuous degree of networks. (3). We summarize the characteristic and research status of RSVP-TE protocol in GMPLS network model, and introduce the overall structure of RSVP-TE as message type, object and connection process. Then we build a simulation platform to test the basic functions, expansible functions and abnormal conditions of RSVP-TE protocol. The design of function modules and data structures are given, as well as the source codes of several key modules. |
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