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1.
The constraint of signal transmission quality and network resources utilization in transparent optical networks are herein addressed through a representative cost function based upon an impairment-constraint-base routing (ICBR) approach, taking into account link capacity utilization and the nonlinear physical effect, in the primary instance due to Four-Wave Mixing (FWM)-induced crosstalk. The FWM effect is considered one of the most severe physical impairments for the future photonic networks since the accumulation of FWM crosstalk may cause a fatal degradation in the teletraffic network performance. This paper presents an added functionality to the network model design based on all-optical modulation format conversion from conventional on-off keying (OOK) to quadrature phase-shift keying (QPSK) sending more data within the same bandwidth while minimizing the blocking probability. The joint effect of physical impairment (i.e., FWM-induced crosstalk) awareness and two different modulation formats is considered through numerical simulations. The proposed scheme is expected to realize an all-optical transparent interconnection between networks that employ diverse modulation formats. Results show that the proposed FWM-aware Routing and Wavelength Assignment (RWA) algorithm leads to a more realistic system performance while giving a significant improvement on the network performance. 相似文献
2.
In wavelength-routed optical networks, the high-delay introduced by the optical switching fabric for resource reservation
increases critically the lightpath setup delay. In order to minimize the setup delay, Generalized Multi-protocol Label Switching
(GMPLS) introduced the concept of Suggested Label Object (SL), which allows to start reserving and configuring the hardware
with a proposed wavelength from the source node to the destination node. This solution is not optimal in wavelength selective
networks (WSN) (i.e., without wavelengths converters). The need of guaranteeing the wavelength continuity constraint for end-to-end
optical connections, combined with the lack of global wavelength-based link information (the source node is not aware of which
wavelengths are available on each link), makes that the likelihood of establishing a lightpath using the proposed suggested
label may be minimum. In this article, we propose an enhancement to the current GMPLS RSVP-TE signaling protocol with offset
time-based provisioning that minimizes the lightpath setup, improving the overall network performance in terms of blocking
probability and setup delay. Experimental performance evaluation has been carried out in ADRENALINE testbed, a GMPLS-based
intelligent all-optical transport network. 相似文献
3.
In this article, we find that the limiting hop count in a lightpath impacts on the performance of optical networks. Based
on this observation, we propose a dynamic hop count shifting (DYHOS) algorithm that limits the hop count of lightpaths dynamically,
depending on the traffic load. The proposed algorithm searches an available route, while minimizing the waste of network resources
and limiting excessive traffic on the network. Hence, the proposed algorithm increases the network throughput and reduces
the blocking probability. Comparing with shortest path routing and adaptive path routing algorithms, we show the performance
of the proposed algorithm has the lowest blocking probability influenced by the hop count of lightpaths for a given routing
algorithm.
相似文献
Jeonghoon MoEmail: |
4.
We propose a new dynamic RWA algorithm for optical fast circuit switching networks, agile optical networks that can accommodate changing broadband demands. The algorithm utilizes pre-computed prioritized route candidates that reflect statistical information such as traffic distribution characteristics to attain better load balancing. The route priority is periodically distributed over a network and RWA for each path connection demand is processed in a distributed manner. Numerical experiments demonstrate that the algorithm matches the performance of a centralized RWA algorithm that uses all the necessary information on a network. 相似文献
5.
Routing on pre-configured topology for dynamic optical networks 总被引:1,自引:0,他引:1
Yongli Zhao Jie Zhang Dahai Han Lei Wang Wanyi Gu Yuefeng Ji 《Photonic Network Communications》2009,17(3):299-310
6.
7.
Distributed lightpath provisioning in wavelength-division multiplexing (WDM) networks has gained wide research interests.
In this article, we study the performance of distributed lightpath provisioning in WDM networks with dynamic routing and wavelength
assignment (RWA). Specifically, we consider the case where routing of each lightpath is calculated based on globally flooded
link-state information, and wavelength assignment is decided through local information exchanges. Simulation results show
that such schemes steadily outperform those schemes with only global flooding or only local information exchanges. More significantly,
the impacts of various factors on the proposed scheme, including RWA algorithm, network topology, number of wavelengths per
fiber, global flooding interval, and traffic load, have been evaluated. Such evaluations help to achieve some insights useful
for the future developments of efficient lightpath provisioning schemes.
相似文献
Gaoxi XiaoEmail: |
8.
Xu Shao Luying Zhou Teck Yoong Chai Chava Vijaya Saradhi Yixin Wang 《Photonic Network Communications》2008,15(2):171-181
Shared-path protection (SPP) is a capacity- efficient mechanism to provide 100% single-link failure protection in WDM mesh
networks. After the first link failure, however, if reconfiguration is unavailable, a second link failure may lead to tremendous
service interruption. Vulnerability of a link is the percentage of links that are vulnerable to the arbitrary second link
failure after the link failed and network vulnerability is defined as the average vulnerability of links in the network. In
this article, we present three policies that can reduce network vulnerability by reducing backup sharing in shared-path protection.
The first policy tries to restrict the times of sharing a wavelength-link by connections. The second policy tries to avoid
backup sharing on highly vulnerable links. The third policy tries to avoid backup sharing on highly vulnerable wavelength-links.
Algorithms to implement these policies based on a similar framework are presented. Numerical results suggest that there is
a trade-off between capacity efficiency and network vulnerability in all the three policies. The third policy can deliver
a better performance in terms of blocking probability and network vulnerability.
相似文献
Yixin WangEmail: |
9.
在光网络中,光信号沿着路由与波长分配(RWA)算法选定的光通路传输的过程中会受到各种信号损伤的影响而导致信号质量的不断下降,严重影响着业务的服务质量(QoS).而光网络中多样化的客户层业务往往有着不同的QoS的需求,因此有必要根据不同的业务QoS需求对光信号损伤的影响进行不同程度的控制.针对这一问题,提出了一种能同时考虑信号损伤限制和服务质量区分的动态RWA算法,并通过计算机仿真的方法对其性能进行了分析和验证.结果表明:该算法既能克服光网络中信号损伤的影响又能为不同级别的业务提供不同的QoS保证,更贴近实际需求. 相似文献
10.
一种提高光网络攻击容忍性的RWA算法研究 总被引:1,自引:0,他引:1
通过研究光网络中带内串扰攻击及其传播原理,在基于串扰攻击有限传播的模型之上,提出了一种限制串扰攻击传播的波长路由分配(Routing and Wavelength Assignment,RWA)算法.该算法把分配后能产生最小串扰攻击传播最大值(Crosstalk Attack Propagation Maximum,CAPM)的波长路由分配给新的光路请求,从而减少全网的潜在的攻击传播范围.仿真结果显示,与常用的首次命中(Fist-fit)RWA算法相比,该算法能显著降低全网的串扰攻击传播最大值,从而提高光网络的攻击容忍性. 相似文献
11.
Helder A. Pereira Daniel A. R. Chaves Carmelo J. A. Bastos-Filho Joaquim F. Martins-Filho 《Photonic Network Communications》2009,18(2):137-149
We propose a model that considers several physical impairments in all-optical networks based on optical signal-to-noise degradation.
Our model considers the gain saturation effect and amplified spontaneous emission depletion in optical amplifiers, coherent
crosstalk in optical switches, and four-wave mixing in transmission fibers. We apply our model to investigate the impact of
different physical impairments on the performance of all-optical networks. The simulation results show the impact of each
impairment on network performance in terms of blocking probability as a function of device parameters. We also apply the model
as a metric for impairment-constraint routing in all-optical networks. We show that our proposed routing and wavelength assignment
algorithm outperforms two common approaches.
相似文献
Joaquim F. Martins-Filho (Corresponding author)Email: |
12.
随着光网络规模的不断增大,下一代智能光网络将被划分为多个路由域进行分布式管理.由于在这种具有分布式特点的多域光网络中,每个路由域只了解本地子网内的拓扑和资源信息,因此以往光网络中已有的基于全网信息的动态RWA算法将不在有效.文章首先分析了多域光网络中的动态RWA问题,然后针对多域网的特点对已有的RWA算法进行了修改,并在给定的多域光网络模型中对该算法进行了仿真研究.结果表明:在多域网络环境下,以往的动态RWA算法急需改进. 相似文献
13.
This article proposes a new approach for routing and wavelength assignment (RWA) for permanent and reliable wavelength paths
(WP) in wide all-optical WDM networks with wavelength continuity constraint. Given a number of available wavelengths on each
optical fiber, for each simple link failure of the network, we seek to maximize the number of satisfied requests for connections.
This is known as RWAP problem. In our algorithm, called RWA with Minimum Loaded Link for Permanent and Reliable wavelength
paths (MLL-PR), routing is based on the search for the optimal path while trying to minimize the maximum load on the links of the network
in order to minimize the maximum link capacity and then minimize the number of dropped lightpaths after any link failure.
The wavelength assignment is based on a graph coloring method using tabu-search. A series of experiments using two well-known
networks (ARPANET and NSFNET) have been carried out in order to evaluate the performance of our approach, in terms of the
number of blocked demands, for different failure scenarios. Generally, our results are better than those provided by the current
solving approaches taken as reference.
相似文献
Zouhair GuennounEmail: |
14.
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: |
15.
We consider the problem of traffic grooming in WDM ring networks. Traffic grooming is a variant of the well-known logical topology design problem, and is concerned with the development of techniques for combining low speed traffic components onto high speed channels in order to minimize network cost. Previous studies have focused on aggregate representations of the network cost. In this work, we consider a Min-Max objective, in which it is desirable to minimize the cost at the node where this cost is maximum. Such an objective is of high practical value when dimensioning a network for unknown future traffic demands and/or for dynamic traffic scenarios. We present new theoretical results which demonstrate that traffic grooming with the Min-Max objective is NP-complete even when wavelength assignment is not an issue. We also present new polynomial-time traffic grooming algorithms for minimizing the maximum electronic port cost in both unidirectional and bidirectional rings. We evaluate our algorithms through experiments with a wide range of problem instances, by varying the network size, number of wavelengths, traffic load, and traffic pattern. Our results indicate that our algorithms produce solutions which are always close to the optimal and/or the lower bound, and which scale well to large network sizes, large number of wavelengths, and high loads. We also demonstrate that, despite the focus on minimizing the maximum cost, our algorithms also perform well in terms of the aggregate electronic port cost over all ring nodes. 相似文献
16.
17.
A hierarchical network model can effectively reduce the complexity of routing and wavelength assignment (RWA) in wavelength
division multiplexing (WDM) networks compared to a flat model. However, the resource utilization may greatly suffer if the
hierarchical architecture is not properly arranged. By considering the degree of each WDM node and the location effect, this
paper proposes a systematic approach to construct the hierarchical topology in WDM networks so that resource utilization can
be maximized. Simulation results demonstrate that the performance of the proposed scheme is superior to that of another scheme.
相似文献
Yen-Wen Chen (Corresponding author)Email: |
18.
全光网静态路由选择和波长分配的分层图算法 总被引:1,自引:0,他引:1
文章提出一种将路由选择和波长分配结合起来的启发式的路由选择和波长分配(RWA)算法.通过这种新的分层图算法和限制光跳距的加权系数来优化全光网的静态路由选择和波长分配,使建立光连接时所需的波长数达到最少.最后对实际的ARPANet等5种光网络进行了计算机仿真,证明了本算法比以前的算法有更好的性能. 相似文献
19.
《Optical Fiber Technology》2014,20(3):228-234
Optical network-on-chip (NoC) is a new designing of Multi-Processor System-on-Chip (MPSoC). Global bus is the simplest logical topology of optical NoC. Static routing and wavelength assignment is one important communication mechanism of optical NoC. This paper addresses the routing and wavelength assignment (RWA) problem for locally twisted cube communication pattern on global bus optical NoC. For that purpose, a routing scheme, that is an embedding scheme, is proposed, and a wavelength assignment scheme under the embedding scheme is designed. The number of required wavelengths is shown to attain the minimum, guaranteeing the optimality of the proposed scheme. 相似文献