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In this letter, we study the multicast protection problem in sparse‐splitting wavelength‐division multiplexing (WDM) optical network, and propose a novel multicast protection algorithm called the shared source‐leaf path‐based protection (SLPP) algorithm. Unlike the proposals in previous studies, the backup paths derived by SLPP can share wavelength with the primary tree in sparse‐splitting WDM networks. Simulations are used to evaluate the effectiveness of the SLPP algorithm. 相似文献
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This paper addresses the problem of multicast wavelength assignment for sparse wavelength conversion (MWA-SWC) in wavelength-routed wavelength-division-multiplexing (WDM) networks. It aims to optimally allocate the available wavelength for each link of the multicast tree, given a sparse wavelength conversion network and a multicast request. To our knowledge, little research work has been done to address this problem in literature.In this paper, we propose a new technique called MWA-SWC algorithm to solve the problem. The algorithm first maps the multicast tree from the sparse conversion case to the full conversion case by making use of a novel virtual link method to carry out the tree mapping. The method provides a forward mapping to generate an auxiliary tree as well as a reverse mapping to recover the original tree. Applying the auxiliary tree, we propose a dynamic programing algorithm for the wavelength assignment (WA) aiming to minimize the number of wavelength converters (NWC) required. Simulation results show that our new algorithm outperforms both random and greedy algorithms with regard to minimizing the NWC. Testing on various scenarios by varying the number of wavelength conversion nodes in the tree has confirmed the consistency of the performance. The primary use of the MWA-SWC algorithm is for static traffic. However, it can also serve as a baseline for dynamic heuristic algorithms. Typically, the MWA-SWC algorithm will provide great benefit when the number of available wavelengths on each link of the multicast tree is relatively large and the performance advantage is significant. 相似文献
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With the rapid development of optical networking technology, it is now a realizable technique to support point-to-multipoint connections directly on the optical layer, giving rise to optical multicast. The topic of optical multicast has attracted much enthusiasm in recent years for the reason that it will not only make full use of the abundant bandwidth provided by optical fibers, but also take full advantage of multicast over the traditional point-to-point connection approach. In this paper, we present a comprehensive review of optical multicast over wavelength-routed WDM networks, covering the development of both data plane and control plane designs. In particular, we provide an up-to-date state-of-the-art review on the multicast routing and wavelength assignment problem. To the best of our knowledge, this is the most thorough and comprehensive review conducted so far on this topic in the literature. 相似文献
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Multicast routing allows network sources to use network resources efficiently by sending only a single copy of data to all group members. In the delay constrained group multicast routing problem (DCGMRP), every group member is also a source, and has an individual minimal delay and bandwidth requirement. The routing algorithm must, for each member of the group, construct a source‐based routing tree spanning all the other member nodes without exceeding the capacities of the traversed links, while satisfying the stated delay constraints. Previous work adopted the direct, intuitive approach by first creating a source‐based multicast tree independently for each member node, and then iteratively locating network links whose capacity constraint are violated and eliminating the violation by rerouting the trees. In this paper, we investigate a number of efficient and effective algorithms, DCGM _ IA +, DCGM _ GR and DCGM _ CP , for solving DCGMRP and compare their performance with previous proposals. Through extensive experiments, our proposals are shown to outperform previous algorithms in constructing group multicast trees with low costs and high success ratios. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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WDM网络中支持QoS的路由与波长分配算法 总被引:1,自引:1,他引:1
针对波分复用(wDM)网络中的路由与波长分配问题。提出了一种支持服务质量(QoS)的约束搜索算法。基于多目标规划模型,这种搜索算法可为网络各节点创建路由表,根据路由表信息求出非支配路径集合,从而一次性完成寻找路由和分配波长两项任务。仿真实例证明了该算法的有效性。 相似文献
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波分复用(WDM)技术的开发和应用使得网络中的信息容量得到了极大的提高,而网络中业务信息的多样化则促进了多播技术的应用和发展。多播的出现使网络的节点结构、虚拟拓扑连接方式及路由和流量疏导算法变得更加复杂多样。为此对光网络中各种多播方式及节点结构并对现有的路由和波长分配算法进行了评述。在此基础上提出了对这类光网络中的信息流量进行疏导时应遵循的几个基本原则,目的是提高波长容量的利用率,减少网络中所用的波长和分插复用器(ADM)数,降低网络的成本和费用。 相似文献
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Multimedia applications, such as video‐conferencing and video‐on‐demand, often require quality of service (QoS) guarantees from the network, typically in the form of minimum bandwidth, maximum delay, jitter and packet loss constraints, among others. The problem of multicast routing subject to various forms of QoS constraints has been studied extensively. However, most previous efforts have focused on special situations where a single or a pair of constraints is considered. In general, routing under multiple constraints, even in the unicast case is an NP‐complete problem. We present in this paper two practical and efficient algorithms, called multi‐constrained QoS dependent multicast routing (M_QDMR) and (multicasting routing with multi‐constrained optimal path selection (M_MCOP)), for QoS‐based multicast routing under multiple constraints with cost optimization. We provide proof in the paper that our algorithms are correct. Furthermore, through extensive simulations, we illustrate the effectiveness and efficiency of our proposals and demonstrate their significant performance improvement in creating multicast trees with lower cost and higher success probability. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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Virtual Source Based Multicast Routing in WDM Optical Networks 总被引:2,自引:0,他引:2
Wavelength-division multiplexed (WDM) networks using wavelength-routing are considered to be potential candidates for the next generation wide-area backbone networks. Multicasting is the ability to transmit information from a single source node to multiple destination nodes and is becoming an important requirement in high-speed networks. As WDM technology matures and multicast applications become increasingly popular, supporting multicast routing at the WDM layer becomes an important and yet a challenging topic. This paper concerns with the problem of optical multicast routing in WDM networks. A few nodes in the network may have wavelength conversion and/or splitting capabilities. In this paper, a new multicast tree construction algorithm is proposed. This algorithm is based on a concept called virtual source. A virtual source is a node having both the splitting and wavelength conversion capabilities. By exploiting the presence of virtual source nodes, the proposed algorithm achieves improved performance. To further improve the performance, the algorithm assigns priorities to nodes based on their capabilities. The effectiveness of the proposed algorithm is verified through extensive simulation experiments. 相似文献
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We study online multicasting in WDM networks with shared light splitter bank. Our objective is either to maximize the network
throughput or to minimize the blocking probability. Due to the nature of dynamic requesting for network resources by online
multicast requests, the network usually is unable to allocate the resources needed for each request in advance. Instead, it
either accepts the request by building an economic multicast tree for the request, in terms of the utilization of the network
resources if it has sufficient resources available, or rejects the request, otherwise. It is desirable that the cost of realizing
each multicast request be minimized, and the network throughput will be maximized ultimately through the cost saving on each
individual request. Since optical light splitting and wavelength conversion switching in optical networks is cost expensive
and its fabrication is difficult, it is assumed that only a limited number of light splitters and wavelength converters are
installed at a node, which will be shared by all the incoming signals at the node. In addition, it is further assumed that
only a fraction of nodes in the network are installed with such optical switches. In this article we first propose a cost
model for realizing an online multicast request under such network environments with limited light splitters and wavelength
converters, which models the cost of utilization of network resources, particularly in modeling the light splitting and wavelength
conversion ability at nodes. We then show that finding a cost-optimal multicast tree for a multicast request under the proposed
cost model is NP-complete, and instead devise approximation and heuristic algorithms for it. We finally conduct experiments
to evaluate the performance of the proposed algorithms. The results show that the proposed algorithms are efficient and effective
in terms of network throughput.
相似文献
Weifa LiangEmail: |
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Most existing algorithms for the problem of optical signal splitter placement or multicast splitting-capable node placement
in a WDM network are based on the performance of attempting a large set of randomly generated multicast sessions in the network.
Experiments show that placement of multicast capable nodes based on their importance for routing one set of multicast sessions
may not be a right choice for another set of multicast sessions. In this work, we propose placement algorithms that are based
on network topology and the relative importance of a node in routing multicast sessions, which is measured by our proposed
metrics. Since a network topology is fixed once given, the proposed algorithms are essentially network traffic independent.
We evaluate the proposed placement algorithms given static sets of multicast sessions as well as under dynamic traffic conditions,
which are routed using our splitter constrained multicast routing algorithm. Our results show that the proposed algorithms
perform better, compared to existing algorithms. 相似文献
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In this paper, we have proposed one wavelength assignment strategy for optical networks which assigns the wavelength according to minimum connection count. The performance of proposed strategy is compared with the most commonly used strategy among the existing strategies in terms of number of searches to find the wavelength for connection establishment. The searching takes the time and directly affects the connection establishment time. The simulation is done using different network models. The results show that the proposed strategy is much better than existing strategy in terms of number of searches required to find a wavelength for establishing the connection and hence connection establishment time reduces. 相似文献
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A cross‐layer optimization for maximum‐revenue‐based multicast in multichannel multiradio wireless mesh networks 下载免费PDF全文
Given a video/audio streaming system installed on a multichannel multiradio wireless mesh network, we are interested in a problem concerning about how to construct a delay‐constrained multicast tree to support concurrent interference‐free transmissions so that the number of serviced mesh clients is maximized. In this paper, we propose a heuristic approach called cross‐layer and load‐oriented (CLLO) algorithm for the problem. On the basis of the cross‐layer design paradigm, our CLLO algorithm can consider application demands, multicast routing, and channel assignment jointly during the formation of a channel‐allocated multicast tree. The experimental results show that the proposed CLLO outperforms the layered approaches in terms of the number of serviced mesh clients and throughputs. This superiority is due to information from higher layers can be used to guide routing selection and channel allocation at the same time. As a result, the CLLO algorithm can explore more solution spaces than the traditional layered approaches. In addition to that, we also propose a channel adjusting procedure to enhance the quality of channel‐allocated multicast trees. According to our simulations, it is proved to be an effective method for improving the performance of the proposed CLLO algorithm. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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带宽密集型的多媒体应用对现有网络提出了新的要求,组播技术有助于解决其在网络带宽和服务质量方面的问题,而在光层实现组播具有更简单、高效的特点.然而,光层组播由于光缓存、光分束和光波长变换等光器件的限制,呈现出和IP层组播不同的特点.对IP层和光层组播进行了讨论,分析了光层组播模型,并对稀疏光分束和稀疏波长变换的光网络组播路由提出了重路由到源和重路由到相关节点两种重路由方式. 相似文献
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WDM光传送网的设计与操作 总被引:1,自引:1,他引:0
综述一WDM光传送网的设计和操作问题,首先介绍了一些基本概念,然后给出了有关WDM光传送网的不同问题及其设计方法,最后描述了对WDM光传送网进行操作的一此算法。 相似文献
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Jean-Marc Hyppolite Philippe Galinier Samuel Pierre 《Photonic Network Communications》2008,15(2):123-130
This paper proposes a tabu search heuristic for solving the routing and wavelength assignment problem in multigranular optical
networks, considering the wavelength-continuity constraint and a set of connections to satisfy. For a number of fibers per
link, a number of wavebands per fiber, and a number of wavelengths per waveband, this algorithm attempts to minimize the total
number of ports used in the network by efficiently grouping lightpaths into bands and fibers, and switching the whole bands
and fibers. The algorithm has been implemented and tested on the NSFNET network, and comparisons have been made with the Balanced
Path Routing and Heavy Traffic First (BPHT) algorithm in terms of number of ports. Generally, the results obtained with our
tabu search heuristic are better than those provided by this algorithm.
相似文献
Samuel PierreEmail: |