本文選題：光網(wǎng)絡 + RWA��； 參考：《電子科技大學》2014年碩士論文

【摘要】：隨著網(wǎng)絡技術(shù)和服務的不斷演進和革新,各種應用層出不窮,內(nèi)容出現(xiàn)爆發(fā)式增長,傳送網(wǎng)承載的流量迅猛增長,為了緩解或根治傳送網(wǎng)的壓力,人們把目光轉(zhuǎn)向了網(wǎng)絡架構(gòu)升級或重構(gòu),于是涌現(xiàn)了一股以CCN為代表的內(nèi)容中心網(wǎng)絡和以O(shè)penFlow協(xié)議為代表的SDN網(wǎng)絡的研究熱潮。然而,無論是內(nèi)容中心網(wǎng)絡還是SDN網(wǎng)絡,傳送網(wǎng)的路由規(guī)劃都是解決問題的關(guān)鍵之一。對業(yè)務的路由規(guī)劃將直接影響到傳送網(wǎng)的業(yè)務接納能力和資源利用能力。本文以SDN下的PCE系統(tǒng)作為切入點來研究光網(wǎng)絡作為傳送網(wǎng)(OTN)的路由規(guī)劃問題。光網(wǎng)絡的路由規(guī)劃,需考慮光網(wǎng)絡自身的約束,主要有波長連續(xù)性和光參損耗。所謂的波長連續(xù)性是指同一光路在其所經(jīng)過的光纖鏈路上須使用同一波長;光參損耗是指任意業(yè)務節(jié)點對間建立連接須克服光信號在傳輸過程中出現(xiàn)的非線性衰減。文獻中把光網(wǎng)絡下的路由問題稱為RWA,近二十年內(nèi)提出了大量靜態(tài)和動態(tài)RWA算法,其中不乏優(yōu)秀的建模,例如波長分層圖模型,然而大部分RWA算法并未考慮光節(jié)點的波長轉(zhuǎn)換能力以及光參損耗約束。本文針對不同的業(yè)務下發(fā)場景,提出了解決上述多約束的有路通路由算法和最優(yōu)中繼分配算法。針對離散到達的新業(yè)務,本文提出了自下而上和自上而下兩種解決方案。與傳統(tǒng)的RWA算法相似,自下而上的解決方案采用在物理拓撲上直接計算前K條備選最短路,然后順序?qū)溥x路進行多約束條件地校驗,最后進行波長資源分配;自上而下的解決方案通過預處理光參損耗約束生成可達表,利用可達表構(gòu)造虛拓撲,在虛拓撲上進行選路并最終實現(xiàn)物理路由映射和波長資源分配。波長資源分配采用First-fit策略。本文通過實驗對自下而上和自上而下的解決方案進行對比,選擇了性能更優(yōu)的自上而下的解決方案來設(shè)計有路通路由算法。針對網(wǎng)絡故障生成的重路由業(yè)務,本文提出了最優(yōu)中繼分配算法,是一種多目標算法,試圖通過合理分配中繼資源達到低阻塞率、少使用中繼資源的目標。通過業(yè)務類型分析,將原問題分解為單中繼、雙中繼和多中繼分配三個子問題。針對前兩個子問題分別提出了構(gòu)建單中繼互斥模型從而轉(zhuǎn)換為二部圖的最大匹配問題和構(gòu)建分層配對關(guān)系模型從而轉(zhuǎn)換為最大配對最大匹配問題的最優(yōu)算法,并分析了算法的時間復雜度;對于多中繼分配子問題,給出了近優(yōu)解算法。通過和有路通路由算法對比,最優(yōu)中繼分配算法能有效減少業(yè)務阻塞,提高資源利用率。
[Abstract]:With the continuous evolution and innovation of network technology and service, various applications emerge in endlessly, the content appears explosive growth, the traffic of transport network increases rapidly, in order to alleviate or cure the pressure of transmission network, People have turned their eyes to upgrading or reconstructing the network architecture, so there is a wave of research on CCN and SDN represented by OpenFlow protocol. However, routing planning of transport networks is one of the key problems in both content-centric networks and SDN networks. Routing planning will directly affect the transport network's ability to accept services and utilize resources. In this paper, the PCE system under SDN is used as the starting point to study the routing planning problem of optical network as transport network (OTNN). The routing planning of optical networks needs to consider the constraints of optical networks, including wavelength continuity and optical parameter loss. The so-called wavelength continuity means that the same wavelength must be used in the optical link through which the same optical path must be used, and the optical parameter loss means that the nonlinear attenuation of the optical signal in the transmission process must be overcome when the connection between any service node is established. In the literature, the routing problem in optical networks is called RWA. In the last 20 years, a large number of static and dynamic RWA algorithms have been proposed, among which there are many excellent models, such as wavelength layering graph model. However, most RWA algorithms do not take into account the wavelength conversion ability and optical parameter loss constraints of optical nodes. In this paper, we propose a multi-constraint routing algorithm and an optimal relay allocation algorithm for different traffic scenarios. In this paper, two solutions, bottom-up and top-down, are proposed for new discrete arrival services. Similar to the traditional RWA algorithm, the bottom-up solution directly calculates the first K alternative shortest path on the physical topology, then verifies the alternative path with multiple constraints sequentially, and finally carries out wavelength resource allocation. The top-down solution generates reachable tables by pre-processing optical parameter loss constraints, constructs virtual topologies by using reachable tables, selects paths on virtual topologies and finally implements physical routing mapping and wavelength resource allocation. First-fit strategy is used in wavelength resource allocation. In this paper, the bottom-up and top-down solutions are compared through experiments, and a top-down solution with better performance is selected to design the routing algorithm. For the rerouting services generated by network faults, this paper proposes an optimal relay allocation algorithm, which is a multi-objective algorithm, which attempts to achieve the goal of low blocking rate and less use of relay resources through rational allocation of relay resources. By analyzing the service types, the original problem is decomposed into three sub-problems: single relay, double relay and multi-relay assignment. For the first two sub-problems, the optimal algorithm for constructing a single relay mutex model to convert to a bipartite graph and a hierarchical pairing relationship model for the maximum matching problem are proposed, respectively. The time complexity of the algorithm is analyzed, and the near optimal solution algorithm is given for the multi-relay assignment subproblem. Compared with the routing algorithm, the optimal relay allocation algorithm can effectively reduce traffic congestion and improve resource utilization.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.1

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本文編號：2012622