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1.
In general, multicast routing and wavelength assignment (MC-RWA) can be subdivided in routing and wavelength assignment issues in wavelength-division multiplexing (WDM) mesh networks. Previous studies on WDM multicast have mainly focused on WDM multicast routing. The multicast wavelength assignment problem is studied in this paper. A unicast routing path can be established by a lightpath in an all-optical network. However, in the multicasting case, a multicast routing tree can be established by a single light-tree or several lightpaths, or a combination of several light-trees and lightpaths. We propose a wavelength assignment algorithm for finding an optimal combination of lightpaths and light-trees to construct a newly required multicast session. First of all, two cost functions are given to evaluate the establishing cost for each feasible wavelength, and then find a set of wavelengths that covers all destinations with the minimal cost using Integer Linear Programming (ILP) formulation. We focus on maximizing the total number of users served in a multicast session and the network capacity. The simulation results show that the proposed algorithm can improve system resource utilization and reduce the blocking probability compared with the First-Fit algorithm.This research was partially supported by the Grant of National Science Council, R.O.C. (NSC 94-2745-E-155-007-URD). 相似文献
2.
Routing and wavelength assignment in WDM all-optical networks 总被引:3,自引:0,他引:3
Kyungsik Lee Sungsoo Park Kyung-Il Choe Cheehang Park 《Electronics letters》2000,36(11):964-966
A new mathematical formulation of the routing and wavelength assignment in wavelength division multiplexing (WDM) all-optical networks is proposed. Which yields tight linear programming lower bounds on the wavelength requirements both theoretically and computationally. An efficient procedure computing lower bounds is also presented together preliminary computational results. 相似文献
3.
Jianping Wang Xiangtong Qi Biao Chen 《Networking, IEEE/ACM Transactions on》2006,14(1):169-182
Multicast is an important application in all-optical WDM networks. The wavelength assignment problem for WDM multicast is to assign a set of wavelengths to the links of a given multicast tree. In an all-optical WDM network without wavelength conversions, wavelength assignment is the key to guarantee the quality of service and to reduce communication costs. In this paper, we study wavelength assignment for WDM multicast with two criteria, to cover the maximum number of destinations, and to minimize the wavelength costs. The computational complexity of the problem is studied. Three heuristic algorithms are proposed and the worst-case approximation ratios for some heuristic algorithms are given. We also derive a lower bound of the minimum total wavelength cost and an upper bound of the maximum number of reached destinations. The efficiency of the proposed heuristic algorithms and the effectiveness of the derived bounds are verified by the simulation results. 相似文献
4.
The issue of wavelength assignment is one of the most important factors that affect the capacity for the deployment of optical
networks. This issue becomes more critical for multicast connections, especially when the network nodes have no wavelength
conversion capability. Although the wavelength assignment can be more flexible if each node can perform wavelength conversion,
the deployment cost increases accordingly. A compromise is to support a limited portion of conversion nodes in the WDM network.
We propose a systematic approach for the wavelength assignment of multicast connections in WDM networks with sparse wavelength
conversion nodes. The efficiency of the arrangement of wavelength is measured by its influences on the available capacity
of the network and the consumption of wavelengths. By using the proposed approach, the Static Cost Greedy (SCG) algorithm
[8] can be easily extended to be applicable in a Sparse Wavelength Conversion Network (SWCN). In addition, instead of SCG,
the Minimum-Effect-First (MEF) algorithm is proposed to maximize the network capacity during wavelength assignment. We compare
the performance of the proposed MEF methods with the extended SCG scheme through exhaustive simulations. The experimental
results indicate that the proposed MEF schemes demonstrate much better performance than the SCG scheme. We also found that
the performance is not always improved proportionally to the increment of the wavelength conversion nodes. The improvement
reaches saturation when the number of conversion nodes is above 35% of the total number of nodes.
相似文献
I-Hsuan PengEmail: |
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N. Yan E. Tangdiongga H. D. Jung I. Tafur Monroy H. de Waardt A. M. J. Koonen 《Photonic Network Communications》2008,15(1):1-6
We experimentally demonstrate regenerative all-optical wavelength multicast by simultaneous multi-wavelength conversion of
10 Gb/s non-return-to-zero signals to four ITU 100 GHz spaced channels with a receiver sensitivity improvement of 1.84 dB
and less than 0.14 dB difference among all the multicast channels, using a single commercial monolithically integrated SOA-MZI.
The multicast device also exhibited about 22 dB optical signal-to-noise ratio enhancement for all the converted channels compared
to the original signal channel without wavelength conversion. Our experiment for the first time revealed the regeneration
properties of a SOA-MZI device for WDM wavelength multicast purposes, and proved the excellent performance of a simple scheme
for various future network and system applications, such as all-optical wavelength routing and grid networking. 相似文献
7.
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
8.
We study the problem of multicast routing and wavelength assignment (MC-RWA) in multi-hop optical WDM networks with respect
to several target functions. Specially, we first study the MC-RWA problem under the target of minimize maximum hops, an efficient
MC-RWA algorithm was proposed for that case. But for the objective of minimizing the total number of wavelength conversions,
problem turns out to be NP-hard, we proposed a new approximation MC-RWA algorithm based on group Steiner tree. At last, combining
the two objectives, a bi-factor approximation algorithm was introduced to minimize the both targets in the system simultaneously. 相似文献
9.
Xiaowen Chu Bo Li 《Networking, IEEE/ACM Transactions on》2005,13(3):704-715
Blocking probability has been one of the key performance indexes in the design of wavelength-routed all-optical WDM networks. Existing research has demonstrated that an effective Routing and Wavelength Assignment (RWA) algorithm and wavelength conversion are two primary vehicles for improving the blocking performance. However, these two issues have largely been investigated separately; in particular the existing RWA algorithms have seldom considered the presence of wavelength conversion. In this paper, we firstly demonstrate that the existing dynamic RWA algorithms do not work well in the presence of wavelength conversion as they usually only take into account the current traffic, and do not explicitly consider the route lengths. We then propose a weighted least-congestion routing and first-fit wavelength assignment (WLCR-FF) algorithm that considers both the current traffic load and the route lengths jointly. We further introduce an analytical model that can evaluate the blocking performance for WLCR algorithm. We carry out extensive numerical studies over typical topologies including ring, mesh-torus, and the 14-node NSFNET; and compare the performance of WLCR-FF with a wide variety of existing routing algorithms including static routing, fixed-alternate routing and least-loaded routing. The results conclusively demonstrate that the proposed WLCR-FF algorithm can achieve much better blocking performance in the presence of sparse or/and full wavelength conversion. 相似文献
10.
For the purpose of reducing the complexity and cost of optical large-scale cross-connect, wavelengths are grouped into wavebands
or fiber to be switched as a single entity, which is called multi- granularity switching. However, it introduces more complexity
into the routing and wavelength assignment problem. In this paper, we propose a novel graph model for describing the states
of the multi-granularity switching WDM networks. Based on the model, the dynamic routing and wavelength assignment problems
for multi-granularity traffic can be solved jointly, and different on-line wavelength grooming policies can be achieved simultaneously.
By simulation, we compared the performance of our algorithms under different policy and different percent of fibers for fiber
switching. The result proved that our algorithms yield better performance than those deal with the routing and wavelength
assignment separately.
This work was supported in part by NSFC Project No. 90104003, 60272023, 60372025 and National 863 project No. 2005AA122310. 相似文献
11.
Amin Ebrahimzadeh Akbar Ghaffarpour Rahbar Behrooz Alizadeh 《Optical Switching and Networking》2013,10(4):354-365
Routing and wavelength assignment (RWA) is the most concern in wavelength routed optical networks. This paper proposes a novel binary quadratic programming (BQP) formulation for the static RWA problem in order to balance traffic load among a network links more fairly. Subsequently, a greedy heuristic algorithm namely variable-weight routing and wavelength assignment (VW-RWA) is proposed to solve the developed BQP problem. In this method, the weight of a link is proportional to the link congestion. Performance evaluation results for different practical network topologies show that our proposed algorithm can decrease the number of required wavelengths in the network, blocking rate and variance of used wavelengths in each link. Besides, it is shown that the number of required wavelengths to establish call requests for a given network topology can be reduced at lower cost compared to other heuristics. 相似文献
12.
Wavelength division multiplexing(WDM) has been becoming a promising solution to meet the rapidly growing demands on bandwidth. Multicast in WDM networks by employing free wavelength is an efficient approach to saving bandwidth and cost. However, the free wavelength may not identical between different hops in a multicast light-path, particularly in heavy load optical WDM networks. In order to implement multicast applications efficiently, a network coding(NC) technique was introduced into all-optical WDM multicast networks to solve wavelength collision problem between the multicast request and the unicast request. Compared with the wavelength conversion based optical multicast, the network coding based optical multicast can achieve better multicast performance with paying lower cost. 相似文献
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In sparse light splitting all-optical WDM networks, the more destinations a light-tree can accommodate, the fewer light-trees
and wavelengths a multicast session will require. In this article, a Hypo-Steiner light-tree algorithm (HSLT) is proposed
to construct a HSLT light-tree to include as many destinations as possible. The upper bound cost of the light-trees built
by HSLT is given as N(N − 1)/2, where N is the number of nodes in the network. The analytical model proves that, under the same condition, more destinations could
be held in a HSLT than a Member-Only (Zhang et al., J. Lightware Technol, 18(12), 1917–1927 2000.) light-tree. Extensive simulations
not only validate the proof but also show that the proposed heuristic outperforms the existing multicast routing algorithms
by a large margin in terms of link stress, throughput, and efficiency of wavelength usage. 相似文献
15.
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: |
16.
Considers routing connections in a reconfigurable optical network using WDM. Each connection between a pair of nodes in the network is assigned a path through the network and a wavelength on that path, such that connections whose paths share a common link in the network are assigned different wavelengths. The authors derive an upper bound on the carried traffic of connections (or equivalently, a lower bound on the blocking probability) for any routing and wavelength assignment (RWA) algorithm in such a network. The bound scales with the number of wavelengths and is achieved asymptotically (when a large number of wavelengths is available) by a fixed RWA algorithm. The bound can be used as a metric against which the performance of different RWA algorithms can be compared for networks of moderate size. The authors illustrate this by comparing the performance of a simple shortest-path RWA (SP-RWA) algorithm via simulation relative to the bound. They also derive a similar bound for optical networks using dynamic wavelength converters, which are equivalent to circuit-switched telephone networks, and compare the two cases. Finally, they quantify the amount of wavelength reuse achievable in large networks using the SP-RWA via simulation as a function of the number of wavelengths, number of edges, and number of nodes for randomly constructed networks as well as de Bruijn networks. They also quantify the difference in wavelength reuse between two different optical node architectures 相似文献
17.
在有波长连续性限制的情况下,减少波长预留冲突需要在波长预留时尽量使用不同的波长,这使全网的空闲波长数减少,容易导致大跳数光路的连接请求失败。解决波长预留冲突问题的大多数算法都把解决问题的目标设为降低网络阻塞率,无法兼顾网络中大跳数光路的情况。本文提出了用于全光网中基于跳数的波长分配算法,该算法通过建立跳数与波长之间的相互对应关系,对未来可能发生预留冲突的光路及其要预留的波长进行预测,根据预测尽量使用相同波长,增加全网的空闲波长数。在解决波长预留冲突问题的同时,实现支持大跳数光路连接请求的目标。 相似文献
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基于在波长可变光网络中的波长分层图模型,本文提出了一种在动态业务情况下的支持不同QoS要求的路由波长分配算法,根据客户层业务不同的QoS要求,通过分层图模型中参数的不同取值,对其光路建立请求区别对待,提供不同级别的光路建立.仿真结果表明该算法具有很好的性能,提高了全网的资源利用率,满足了客户层业务在建立光通路时不同的QoS要求对网络阻塞率的要求. 相似文献