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1.
Elastic optical network (EON) technology is considered as a very promising candidate for future high-speed networks due to its intrinsic flexibility and high efficiency in allocating the optical spectrum resources. The key issue that has to be addressed in EON is the routing and spectrum allocation (RSA) problem. RSA is NP-hard problem that has to be solved in an efficient manner. It is a highly challenging task particularly in the case of large problem instances. In this paper, we applied the bee colony optimization (BCO) metaheuristic approach to solve the RSA problem in EON with static traffic demands. The objective of the proposed BCO–RSA algorithm is to minimize both the network spectrum utilization and the average path length criterions. The results of numerous experimental studies show that our BCO–RSA algorithm performs superior compared to some benchmark greedy heuristics as well as to differential evolution (DE) metaheuristic algorithm recently proposed in the literature. The algorithm is evaluated in different realistic size optical networks, such as the NSFnet, two European optical networks (EON-19 and EON-28) and the USA network topology. Simulation results demonstrate that considerable spectrum savings could be achieved with our BCO–RSA algorithm compared to other considered approaches. In addition, we analyzed the efficiency of the BCO–RSA algorithm and compare it with the competitive DE approach according to the required CPU time and the convergence speed. 相似文献
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The emergence of new services demands multicast function in optical network.Because of the high cost and complex architecture of multicast capable (MC) node, splitter-sharing switch structure is introduced in which the light splitters are shared by all input signals.To accommodate to this situation, by extending resource ReSerVation protocol-traffic engineering (RSVP-TE) and open shortest path first-traffic engineering (OSPF-TE), a new optical multicast mechanism is provided and the signaling flow and its finite state machine model are given.At the same time, a multicast routing algorithm in splitter-sharing optical network and a changing link weight policy to balance network traffic are proposed.Simulations in NSFNET show no matter with or without wavelength converters, when the number of splitters is 25% of that demanded by traditional MC nodes, the multicast performance has been close to the ideal circumstance.Wavelength converters and changing link weight help much in improving the traffic performance when the number of splitters is adequate. 相似文献
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在弹性光网络中,光树传输组播可以节省链路代价,但较长的光树需要选择更低的调制等级,消耗更多的频谱资源和发射机功耗.提出一种基于遗传算法的光森林组播和光树重配置(GAMF-TR)优化组播的能效路由、调制格式和频谱分配(RMSA)策略.GAMF-TR策略设计染色体编码表示光森林的组播目的节点划分和光路径组合,通过染色体的基因位概率交叉和变异得到更多的光森林RMSA策略,设计了一个频谱分配效率和发射机功耗折中的适应度函数选择能效最高的光森林RMSA策略,并设计在网络资源充足时将组播从光森林重配置到光树传输,进一步减少发射机功耗的消耗.仿真结果表明:提出的GAMF-TR策略获得了组播的最低带宽阻塞率和最高能效性能. 相似文献
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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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组播应用使光网络的带宽资源日趋紧张。网络编码具有提高带宽利用率、提升网络的吞吐量、改善网络负载均衡等优点。分析了网络编码的特点及其编码代价、传统路由面临的问题,讨论了将网络编码引入光组播,优化光组播路由、提高网络吞吐量和资源利用率的研究方法。 相似文献
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In this paper, we investigate the dynamic multicast routing problem and briefly discuss the common dynamic multicast routing algorithm called Least Load Multicast Routing (LLMR). We propose two new multicast routing algorithms called Least Load Multicast Routing with Maximum Occupied Circuits (LLMRMOC) and Least Load Multicast Routing with Minimum Measured Blocking Time (LLMRMMBT), both of which are based on LLMR. Simulation results show that these algorithms, compared with LLMR, not only produce a smaller network revenue loss, but also result in smaller call blocking probabilities for all classes of traffic. The moderate gain in the network performance comes only a slight additional cost. The implementation issues of the proposed algorithms are also discussed. 相似文献
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为了降低光组播路由 的光域网络编码代价和提高达到理论最大光组播容量的 概率,提出一种基于共享链路和网络编 码的优化光组播容量方法。首先设计一种从多条源- 宿最短路径中选择能达到最大光组播容量的最短路径簇,然后在 最短路径簇中计算路径的共享度,选择共享度高的组播路径传输网络编码信息,构造网络编 码次数最少的光组播编码子图, 解决传统的网络编码组 播路由和最大共享度链路组播路由中存在的网络编码次数过多和达到最大光组播容量概率过 低的问 题。仿真结果表明:本文提出的方法具有最低的网络编码代价,能以最大的概率达到光组播 理论最大容量。 相似文献
9.
Peng Jia Yu Liang Shanguo Huang Jie Zhang Wanyi Gu 《Photonic Network Communications》2008,15(1):83-89
The emergence of new services demands for a multicast function in optical networks. At the same time, wavelength converters
are introduced to increase the efficiency of wavelength usage. It is because of the high cost and complex architecture of
optical multicast and wavelength conversion technology, that a new switch structure is introduced, in which optical splitters
and wavelength converters are shared per-node. In order to accommodate this architecture, a multicast routing and wavelength
assignment algorithm in a splitter–converter-sharing optical network and a changing link weight policy to balance network
traffic are proposed. By extending RSVP-TE (Resource ReSerVation Protocol-Traffic Engineering) and OSPF-TE (Open Shortest
Path First-Traffic Engineering), an optical multicast mechanism is provided, and message type, signaling flow, and finite
state machine model are given. Simulations of NSFNET show that, when the number of splitters and converters are 50% and 12.5%
of the full equipment respectively, the performance is close to the ideal case. Using a changing link weight policy can improve
performance greatly, when there are enough splitters and converters. 相似文献
10.
In this paper, we investigate the dynamic multicast routing problem for single rate loss network and briefly discuss the dynamic multicast routing algorithm called least load multicast routing (LLMR). We propose a new multicast routing algorithm called maximum mean number of new calls accepted before blocking multicast routing (MCBMR), which can more accurately capture the current and future loading of a network. Simulation results show that this algorithm, compared with LLMR, not only has a smaller network revenue loss, but also results in smaller call blocking probabilities for all classes of traffic. We also discuss the implementation issues of our proposed algorithm and develop two approximation methods, state approximation and curve fitting, which can reduce the measurement complexity significantly with only a slight performance degradation 相似文献
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综合业务请求的服务质量(QoS, quality of service)要求、节能要求,以及遭遇单链路或单个节点失效时的生存性要求,提出了一种多粒度传送网中的绿色单播路由保护机制。基于K最短路径算法,计算符合QoS需求的路径;根据最小波长转换次数,在多层辅助图上进行资源分配;根据业务请求的保护等级,提供了三级保护机制。仿真实验基于EON(Europe optical network)拓扑,通过与现有机制在阻塞率、保护/工作资源比和负载均衡度方面的性能对比,表明提出的机制是可行且有效的。 相似文献
12.
针对无线网络中资源受限的组播路由问题,考虑网络节点的节点度限制和网络链路的带宽约束,以最小化组播路由开销为目标,提出了一种二进制编码方式的基于灰狼优化算法的组播路由策略.在给定的网络拓扑下,基于灰狼优化算法的组播路由策略可以迅速找到一棵包含源和目的节点的最小开销组播树.仿真结果表明,相比于遗传算法,所提出的基于灰狼优化... 相似文献
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为了提高无色无向无冲突灵活的可重构光分插复用器(CDC-F ROADM)节点的弹性光网络IP组播频谱-能耗效率,该文提出一种全光组播能效调度算法(AMEESA)。在算法路由阶段,考虑能耗和链路频谱资源使用情况设计链路代价函数,构建最小代价光树算法组播光树。在频谱分配阶段,设计基于高效光谱分辨率(HSR)光树中间节点频谱转换方法,选择节能频谱转换方案为组播光树分配频谱块资源。仿真分析表明,所提算法能有效提升网络能效,降低IP组播带宽阻塞率。 相似文献
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Panchali Datta Choudhury Neha Agarwal Tanmay De 《International Journal of Communication Systems》2020,33(7)
We adopt a fragmentation reducing policy for spectrum assignment and incorporate it with multicast traffic grooming in EON. To reduce fragmentation, the spectrum is partitioned based on the clique partitioning approach and spectral slots are assigned to traffic demands depending on which partition they belong. Simulation results predict that the proposed approach has better spectrum slot utilization compared to the state‐of‐the‐art non‐partitioning approach and the proposed approach reduces fragmentation, and also has less blocking ratio compared to the state‐of‐the‐art partitioning approach. 相似文献
18.
Due to the explosive growth of data-related traffic driven by the Internet, network reliability becomes an important issue. We investigate various protection approaches to handle failures for dynamic traffic demands in IP/MPLS-over-WDM networks. An LSP can be protected at either the IP/MPLS layer or the optical layer. In IP/MPLS layer protection, an LSP is protected by providing a link-disjoint backup LSP between its end nodes. In optical layer protection, an LSP is protected by the backup lightpath of each lightpath traversed by the LSP. We present two integrated routing algorithms: hop-based integrated routing algorithm and bandwidth-based integrated routing algorithm (BIRA) to set up the restorable bandwidth-guaranteed paths efficiently. Then we present a multilayer protection scheme for multiclass traffic in such networks. This scheme takes into account the different QoS and recovery requirements of the traffic to provide protection capability either at the MPLS layer or at the optical layer in a cost-effective manner. We use the connection blocking probability and number of optical-electrical-optical conversions as performance metrics to compare various protection approaches. 相似文献
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Xingwei Wang Lei Guo Jiannong Cao Jingjing Wu Weigang Hou 《Optical Fiber Technology》2010,16(5):292-298
The increase of multimedia service requirements results in the growing popularity of the multicast in Wavelength-Division Multiplexing (WDM) optical mesh networks. Multicast fault tolerance in WDM optical mesh networks is an important issue because failures caused by the traffic carried in WDM optical mesh networks may lead to huge data loss. Previous works have proposed multicast protection algorithms to address the single-fiber link failure dominant in current optical mesh networks. However, these existing algorithms are all mainly based on path protection or segment protection, which may lead to long restoration times and complicated protection switching procedures. This paper therefore proposes a new heuristic algorithm, called Enhanced Multicast Hamiltonian Cycle Protection (EMHCP), in which all working light-trees of multicast demands can be protected by a Hamiltonian cycle in the network. For each multicast demand, EMHCP computes a least-cost light-tree based on the presented link-cost function that considers load balancing and proper straddling link selection so that backup wavelengths on the Hamiltonian cycle can be reduced. Simulation results show that EMHCP can obtain significant performance improvement compared with the conventional algorithm. 相似文献