共查询到18条相似文献,搜索用时 328 毫秒
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为了解决波分复用(WDM)网状网络中的动态流量疏导问题,基于收发器节约辅助图模型,提出了一种资源效率疏导策略.它同时考虑收发器和波长链路两种网络资源的有效利用,根据当前的网络状态动态改变疏导策略,使网络不会由于某一种资源的缺乏而导致阻塞所有流量,避免了另一种资源因富余而造成的浪费,从而两种资源都能得到充分利用.在辅助图模型中,根据两种资源的可用数目比值,对各条边设置不同的权值函数,可轻易地实现该策略.仿真结果证明,不管是收发器资源受限还是波长资源受限,该策略都能取得较好的性能,降低了网络的阻塞率. 相似文献
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在WDM网络中业务的带宽需求远低于一个波长所提供的带宽,业务量疏导可以聚集低速业务到大容量的光路中从而有效地利用波长带宽资源.目前大多数业务量疏导的研究限于环形网,考虑对WDM网状网中低速业务可靠疏导的文献更少.该文综合考虑WDM网状网生存性及业务量疏导,提出了基于波长分层图的共享保护业务量疏导算法(SPTG-LG,Shared Protection Traffic Grooming algorithm ba,sed on wavelength Layered-Graph),并对算法进行了仿真和分析. 相似文献
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为了解决WDM网状网络中的静态流量疏导问题,基于收发器节约辅助图模型,该文提出了一种最少费用疏导策略。它同时考虑收发器和波长链路两种网络资源的费用,为每条流量计算出一条费用最少的路径,以获得网络总费用最少的解决方案。根据两种资源费用的比值关系,给辅助图中的每条边分配不同的权值,使得路径的总权值最小代表了该路径的费用最少,从而就能够轻易地实现该策略。仿真结果证明,不管两种资源的费用比值如何变化,该策略的网络总费用始终是最少的。 相似文献
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光网络中基于组播树的静态业务疏导算法 总被引:2,自引:1,他引:1
为了减少波分复用(WDM)网络中波长资源消耗,将组播路由算法的思想运用于静态业务疏导的计算,通过建立业务疏导树来实现静态业务疏导.为了减少疏导树的数量,从而减少网络中波长资源的消耗,将节点间的业务请求分组归并,利用装包算法使业务分组的数量最少,并通过构建最小生成树实现传输路径共享.仿真结果表明,本文的算法可以有效地减少... 相似文献
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本文研究了WDM业务量疏导网状网中的生存性问题,基于分层图模型提出了一种动态的业务量疏导共享通路保护算法(SPPTG).该算法根据网络拓扑信息、资源使用情况和到达的业务连接请求动态调整波长通道的代价,在此基础上为到达的低速业务连接请求寻找两条链路分离的通路,分别作为工作通路和保护通路,并且保证保护通路尽量共享已有的保护资源,从而有效提高全网的资源利用率.仿真表明SPPTG算法具有很好的阻塞性能,同时可以充分共享保护资源. 相似文献
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Dynamic Grooming Algorithms for Survivable WDM Mesh Networks 总被引:6,自引:0,他引:6
Wen Haibo Li Lemin He Rongxi Yu Hongfang Wang Sheng Song Na 《Photonic Network Communications》2003,6(3):253-263
Within a WDM grooming mesh network and under the constraints of the number of transceivers per node and wavelength continuity, we propose a novel dynamic grooming graph which models the number of transceivers per node in addition to the usage of wavelength and bandwidth resources. Based on the grooming graph, we first propose a dynamic traffic-grooming algorithm called integrated grooming algorithm (IGA). And we also propose two dynamic survivable traffic-grooming algorithms, which are called protection per lightpath traffic-grooming algorithm (PPL) and protection per connection traffic-grooming algorithm (PPC). These algorithms are evaluated via simulations. 相似文献
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A Link Bundled Auxiliary Graph Model for Constrained Dynamic Traffic Grooming in WDM Mesh Networks 总被引:3,自引:0,他引:3
《Selected Areas in Communications, IEEE Journal on》2005,23(8):1542-1555
This paper addresses the two-layer dynamic traffic grooming problem in wavelength-division-multiplexed (WDM) mesh optical networks subject to resource constraints and the generalized wavelength continuity (GWC) constraint. The GWC constraint is a relaxed wavelength continuity constraint which incorporates various kinds of wavelength conversion capabilities that exist in optical networks. As an improvement over the existing layered auxiliary graph (layered-AG) approach which represents each wavelength separately in the auxiliary graph, we introduce a largely simplified link bundled auxiliary graph (LBAG) model and propose the SAG-LB method to find paths and assign wavelengths for new lightpaths subject to the GWC constraint. We propose the constrained integrated grooming algorithm (CIGA) based on the LBAG model. A grooming policy influences the resource utilization by determining the weight function of the auxiliary graph. We propose the least resource path first (LR) grooming policy, which is an improvement over the existing grooming policies in the literature, by integrating the wavelength and transceiver metrics together. Simulation results show that the LBAG model achieves a comparable blocking performance with the layered-AG approach while using a significantly less amount of running time. We also present the worst case time complexity analysis of the CIGA grooming algorithm and evaluate the performance of the LR grooming policy by simulation. 相似文献
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With the size of traffic demands ranges from sub-wavelength-level to wavelength-level, traffic demands need to be aggregated
and carried over the network in a cost-effective manner to make sure that the resources are utilized effectively. Therefore,
the technique called multi-granularity grooming is proposed to save the cost by reducing the number of switching ports in
optical cross-connects. However, the existing multi-granularity grooming algorithms are mostly limited in single-domain optical
networks. Since the current optical backbone keeps enlarging and is actually divided to multiple independent domains for achieving
the scalability and the confidentiality, it is necessary to study the multi-granularity grooming in multi-domain optical networks.
In this paper, we propose a new heuristic algorithm called hierarchical multi-domain multi-granularity grooming (HMMG) based
on hierarchical integrated multi-granularity auxiliary graph (H-IMAG) to reduce the total number of optical switching ports.
The H-IMAG is composed of the inter-domain virtual topology graph (VTG) and the intra-domain integrated layered auxiliary
graph (ILAG), where VTG includes a wavelength virtual topology graph (WVTG) and a waveband virtual topology graph (BVTG),
and ILAG includes a wavelength layered auxiliary graph (WLAG) and a waveBand layered auxiliary graph (BLAG). Then, we can
groom the sub-wavelength-level demands into lightpaths based on WVTG and WLAG and groom the wavelength-level demands into
high-capacity wavebands based on BVTG and BLAG. Simulation results show that performances of H-IMAG can be significantly improved
compared with previous algorithm. 相似文献
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In this article, we consider traffic grooming and integrated routing in IP over WDM networks. The challenges of this problem
come from jointly considering traffic grooming, IP routing, and lightpath routing and wavelength assignment (RWA). Due to
the high bandwidth of optical fiber, there exists a mismatch between the capacity needed by an IP flow and that provided by
a single lightpath. Traffic grooming is therefore used to increase the network utilization by aggregating multiple IP flows
in a single lightpath. However, traffic grooming incurs additional delays that might violate Quality-of-Service (QoS) requirements
of IP users. In this work, the tradeoff between traffic grooming and IP QoS routing is well-formulated as a mixed integer
and linear optimization problem, in which the revenue from successfully provisioning IP paths is to be maximized. Problem
constraints include IP QoS, routing, optical RWA, and the WDM network capacity. We propose a novel Lagrangean relaxation (LGR)
algorithm to perform constraint relaxation and derive a set of subproblems. The Lagrangean multipliers are used in the proposed
algorithm to obtain a solution in consideration of grooming advantage and resource constraints simultaneously. Through numerical
experiments and comparisons between the proposed algorithm and a two-phase approach, LGR outperforms the two-phase approach
under all experimental cases. In particular, the improvement ratio becomes even more significant when the ratio of IP flow
to the wavelength capacity is smaller. 相似文献
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In order to improve the bandwidth utilization efficiency and reduce the blocking probability for multicast requests in optical networks, the multicast traffic grooming approach was proposed to groom a lot of low-speed traffic to a few of high-speed light-trees. At the same time, in order to save the ports and the cost of optical cross-connect, the multicast waveband grooming approach was proposed to groom multiple light-trees to a few of waveband tunnels. However, the existing approaches all did not consider the joint performances of improving bandwidth utilization efficiency, reducing blocking probability and saving ports for multicast requests. Therefore, in this article, we propose a new multicast multi-granular grooming approach to perform the hierarchical sequential grooming to improve the joint performances based on a newly developed integrated auxiliary grooming graph (IAGG) that includes multiple wavelength integrated grooming graphs (WIGGs) and one waveband virtual topology layered graph (BVLG) to support both the multicast traffic grooming and multicast waveband grooming. In order to achieve the map of light-tree to the virtual topology layer in WIGG or BVLG, we present a light-segment map method, where a light-tree will be divided to several light-segments each of which will be independently mapped to the virtual topology layer. Since different definitions of blocking probability may lead to different objectives, we define two kinds of blocking probability, mean blocking probability of requests (MBPR) and mean blocking probability of users (MBPU). According to the two definitions of blocking probability, we propose two multicast multi-granular grooming heuristic algorithms, Heuristic Algorithm with minimizing MBPR and Heuristic Algorithm with minimizing MBPU based on IAGG. Simulation results show that the two proposed algorithms are both efficient and have better performances than traditional multicast grooming algorithm. 相似文献
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IP over WDM网络中能耗自感知的混合疏导专有保护算法 总被引:2,自引:2,他引:0
针对绿色生存性IP over WDM网络中资源开销大、网络阻塞率高的问题,提出一种能耗自感知的混合疏导专有保护(HG-PA-DPP)算法。首先在IP层的核心路由器对低粒度业务请求集中疏导;然后通过实时感知WDM层的链路负载和双层器件带来的链路能耗状态定义链路权值,基于分层图在不同波长平面上为各业务请求寻找权值小且链路分离的工作路径和保护路径,同时在业务的中间节点处对不需要光-电-光转换的光路进行光旁路处理;最后,将空闲或保护资源设置为休眠模式以实现节能。仿真结果表明,所提算法在高负载时有着更好的节能效果,且在大网络拓扑下资源开销(RO)为传统算法的76.5%,阻塞率(BP)仅为传统算法的61.1%。 相似文献
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Survivability is an important issue to ensure the service continuity in optical network. At the same time, with the granularity of traffic demands ranging from sub-wavelength-level to wavelength-level, traffic demands need to be aggregated and carried over the network in order to utilize resources effectively. Therefore, multi-granularity grooming is proposed to save the cost and reduce the number of switching ports in Optical-Cross Connects (OXCs). However, current works mostly addressed the survivable wavelength or waveband grooming. Therefore, in this paper, we propose three heuristic algorithms called Multi-granularity Dedicated Protection Grooming (MDPG), Multi-granularity Shared Protection Grooming (MSPG) and Multi-granularity Mixed Protection Grooming (MMPG), respectively. All of them are performed based on the Survivable Multi-granularity Integrated Auxiliary Graph (SMIAG) that includes one Wavelength Integrated Auxiliary Graph (WIAG) for wavelength protection and one waveBand Integrated Auxiliary Graph (BIAG) for waveband protection. Numerical results show that MMPG has the lowest average port-cost, the best resource utilization ratio and the lowest blocking probability among these three algorithms. Compared with MDPG, MSPG has lower average port-cost, better resource utilization ratio and lower blocking probability. 相似文献
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Hongyue Zhu Hui Zang Keyao Zhu Mukherjee B. 《Networking, IEEE/ACM Transactions on》2003,11(2):285-299
As the operation of our fiber-optic backbone networks migrates from interconnected SONET rings to arbitrary mesh topology, traffic grooming on wavelength-division multiplexing (WDM) mesh networks becomes an extremely important research problem. To address this problem, we propose a new generic graph model for traffic grooming in heterogeneous WDM mesh networks. The novelty of our model is that, by only manipulating the edges of the auxiliary graph created by our model and the weights of these edges, our model can achieve various objectives using different grooming policies, while taking into account various constraints such as transceivers, wavelengths, wavelength-conversion capabilities, and grooming capabilities. Based on the auxiliary graph, we develop an integrated traffic-grooming algorithm (IGABAG) and an integrated grooming procedure (INGPROC) which jointly solve several traffic-grooming subproblems by simply applying the shortest-path computation method. Different grooming policies can be represented by different weight-assignment functions, and the performance of these grooming policies are compared under both nonblocking scenario and blocking scenario. The IGABAG can be applied to both static and dynamic traffic grooming. In static grooming, the traffic-selection scheme is key to achieving good network performance. We propose several traffic-selection schemes based on this model and we evaluate their performance for different network topologies. 相似文献