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1.
As multicast applications becoming widely popular, supporting multicast in wavelength division multiplexing (WDM) networks is an important issue. Currently, there are two schemes to support multicast in WDM networks. One scheme is opaque multicasting which replicate bit stream in electronic domain. And the other is transparent multicasting which replicate bit stream all optically by a light splitter. However, both of two schemes have drawbacks or difficulties. This paper investigates an alternate translucent multicasting scheme, in which a fraction of branch nodes replicate bit stream at electronic domain and the other branch nodes replicate bit stream all optically. Replicating bit stream at electronic domain will introduce electronic processing overhead and extra delay. To satisfy the delay requirement of multicast session, the maximum number of electronic hops of a multicast tree must be less than an upper bound. In this paper, a hop-constrained multicast routing heuristic algorithm called shortest path based hop-constrained multicast routing (SPHMR) is proposed. A series of simulations are conducted to evaluate the effectiveness of translucent multicasting scheme. Simulation results show that the translucent multicasting scheme achieve a good compromise between network performance and network cost as well as power losses caused by light splitting. 相似文献
2.
The advances in wavelength-division multiplexing (WDM) technology are expected to facilitate bandwidth-intensive multicast
applications through light splitting. Due to complexity and cost constraints, light splitting (or optical multicast) nodes
are sparsely configured in a practical WDM network. In this article, we investigate the multicast routing problem under the
sparse light-splitting constraint. An efficient sparse splitting constrained multicast routing algorithm called Multicast
Capable Node First Heuristic (MCNFH) is proposed. The key idea of MCNFH is to include the shortest path, that includes most
of the multicast capable nodes, for configuring the multicast tree. Simulations and comparisons are used to demonstrate the
performance of MCNFH. Simulation results and analysis show that MCNFH builds multicast trees with the least wavelength channel
cost and with the smallest number of wavelengths used per link. In addition, MCNFH requires only one transmitter at the source
node. 相似文献
3.
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
4.
In this paper, the sharing schemes of multicast in survivable Wavelength-Division Multiplexed (WDM) networks are studied and the concept of Shared Risk Link Group (SRLG) is considered. While the network resources are shared by the backup paths, the sharing way is possible to make the backup paths selfish. This selfishness leads the redundant hops of the backup route and a large number of primary lightpaths to share one backup link. The sharing schemes, especially, the self-sharing and cross-sharing, are investigated to avoid the selfishness when computing the backup light-tree. In order to decrease the selfishness of the backup paths, it is important to make the sharing links fair to be used. There is a trade-off between the self-sharing and cross-sharing, which is adjusted through simulation to adapt the sharing degree of each sharing scheme and save the network resources. 相似文献
5.
《Optical Fiber Technology》2014,20(4):341-352
This paper proposes an efficient overlay multicast provisioning (OMP) mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks. To facilitate request provisioning, OMP jointly utilizes a data learning (DL) scheme on the IP/MPLS layer for logical link cost estimation, and a lightpath fragmentation (LPF) based method on the WDM layer for improving resource sharing in grooming process. Extensive simulations are carried out to evaluate the performance of OMP mechanism under different traffic loads, with either limited or unlimited port resources. Simulation results demonstrate that OMP significantly outperforms the existing methods. To evaluate the respective influences of the DL scheme and the LPF method on OMP performance, provisioning mechanisms only utilizing either the IP/MPLS layer DL scheme or the WDM layer LPF method are also devised. Comparison results show that both DL and LPF methods help improve OMP blocking performance, and contribution from the DL scheme is more significant when the fixed routing and first-fit wavelength assignment (RWA) strategy is adopted on the WDM layer. Effects of a few other factors, including definition of connection cost to be reported by the WDM layer to the IP/MPLS layer and WDM-layer routing method, on OMP performance are also evaluated. 相似文献
6.
Nabil abdelkader Nouri Zibouda Aliouat Abdenacer Naouri Soufiene ali Hassak 《International Journal of Communication Systems》2023,36(8):e5468
One of the most challenging tasks is deploying a wireless mesh network backbone to achieve optimum client coverage. Previous research proposed a bi-objective function and used a hierarchical or aggregate weighted sum method to find the best mesh router placement. In this work, to avoid the fragmented network scenarios generated by previous formulations, we suggest and evaluate a new objective function to maximize client coverage while simultaneously optimizing and maximizing network connectivity for optimal efficiency without requiring knowledge of the aggregation coefficient. In addition, we compare the performance of several recent meta-heuristic algorithms: Moth-Flame Optimization (MFO), Marine Predators Algorithm (MPA), Multi-Verse Optimizer (MVO), Improved Grey Wolf Optimizer (IGWO), Salp Swarm Algorithm (SSA), Grey Wolf Optimizer (GWO), Whale Optimization Algorithm (WOA), Harris Hawks Optimization (HHO), Particle Swarm Optimization (PSO), Sine Cosine Algorithm (SCA), and Slime Mould Algorithm (SMA). We empirically examined the performance of the proposed function using different settings. The results show that our proposed function provides higher client coverage and optimal network connectivity with less computation power. Also, compared to other optimization algorithms, the MFO algorithm gives higher coverage to clients while maintaining a fully connected network. 相似文献
7.
The advances in wavelength division multiplexing (WDM) technology are expected to facilitate bandwidth-intensive multicast
application by establishing a light-tree, which regards the source node as the root, and involves all the destination nodes.
The light-tree is sensitive to failures, e.g., a single fiber cut may disrupt the transmission of information to several destination
nodes. Thus, it is imperative to protect multicast sessions. In this work, we investigate the problem of protecting dynamic
multicast sessions in mesh WDM networks against single link failures. Our objectives are to minimize the usage of network
resources in terms of wavelength links for provisioning survivable multicast session, and to reduce the multicast session
blocking probability. We propose two efficient multicast session protecting algorithms, called Optimal Path Pair based Removing
Residual Links (OPP-RRL) and Source Leaf Path based Avoiding Residual Links (SLP-ARL), which try to reduce the usage of network
resource by removing or avoiding residual links in the topology consisting of light-tree and its backup paths. To evaluate
the proposed algorithms, we apply Integer Linear Programming (ILP) to generate an optimal solution. We also compare the proposed
algorithms with existing algorithms through simulation. Simulation results indicate that the two proposed algorithms have
better performance than other existing algorithms in terms of wavelength links required and network blocking probability.
Furthermore, the solutions generated by the two proposed algorithms are quite close to the solutions generated by ILP in terms
of the number of wavelength links required, when the network size is small. 相似文献
8.
In this work, we study dynamic provisioning of multicast sessions in a wavelength-routed sparse splitting capable WDM network
with an arbitrary mesh topology where the network consists of nodes with full, partial, or no wavelength conversion capabilities
and a node can be a tap-and-continue (TaC) node or a splitting and delivery (SaD) node. The objectives are to minimize the
network resources in terms of wavelength-links used by each session and to reduce the multicast session blocking probability.
The problem is to route the multicast session from each source to the members of every multicast session, and to assign an
appropriate wavelength to each link used by the session. We propose an efficient online algorithm for dynamic multicast session
provisioning. To evaluate the proposed algorithm, we apply the integer linear programming (ILP) optimization tool on a per
multicast session basis to solve off-line the optimal routing and wavelength assignment given a multicast session and the
current network topology as well as its residual network resource information. We formulate the per session multicast routing
and wavelength assignment problem as an ILP. With this ILP formulation, the multicast session blocking probability or success
probability can then be estimated based on solving a series of ILPs off-line. We have evaluated the effectiveness of the proposed
online algorithm via simulation in terms of session blocking probability and network resources used by a session. Simulation
results indicate that our proposed computationally efficient online algorithm performs well even when a fraction of the nodes
are SaD nodes. 相似文献
9.
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: |
10.
WDM光网络中光层组播技术的研究 总被引:1,自引:0,他引:1
本文分析了光层组播原理。在物理层实现组播 ,使该技术在整个互联网实施实时交互音像通信和有效抑止“电子瓶颈”效应有着重大作用。文中对两种不同结构具有光层组播的OXC进行了分析比较。并且对WDM光网络中的无阻塞组播通信波长满足条件进行了分析探讨。 相似文献
11.
Optimal and heuristic algorithms for all‐optical group multicast in resource‐constrained WDM networks 下载免费PDF全文
Wen‐Lin Yang Chun‐Tao Yang Yu‐Chung Huang 《International Journal of Communication Systems》2016,29(15):2292-2312
Given a sparse‐splitting wavelength‐division multiplexing network with no wavelength converter, we study a group multicast problem that is how to transmit a number of multicast streams from the video server to multiple destinations simultaneously. To avoid the situation that the wavelengths are used up by the first few requests, one wavelength is available for each multicast request. Hence, some of destinations may not be included in the multicast trees because of the lack of wavelengths. Our goal is to construct a number of light trees with conflict‐free wavelengths for multiple requests so that the number of served clients is maximized. This problem is named as the revenue‐maximized and delay‐constrained group multicast routing problem. We first determine a set of multicast trees with the maximum number of served clients, then followed by the wavelength assignment to allocate the minimum number of wavelengths to the resulting trees. In this study, we propose two Integer Linear Programming ILP‐based algorithms for determining the optimal solutions for the light‐tree construction problem and the wavelength assignment problem, respectively. For large‐scale networks, two heuristics are introduced to solve the light‐tree construction problem approximately. A set of simulations are also provided for comparing performances of our algorithms against the other published methods. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
Performance assessment of multicast node placement for multicast routing in WDM networks with sparse light splitting 总被引:1,自引:0,他引:1
This article examines all-optical multicast routing for wavelength-routed optical networks with sparse Multicast Capable (MC)
nodes in two phases. The first phase is MC node placement and use of a simple and straightforward Maximum Path Count First
(MPCF) algorithm to obtain candidates for MC nodes. The second phase is multicast routing with MC-based schemes that minimizes
the number of wavelength channels with minimum transmission delay as required by a given multicast session, in that a light-tree
is first constructed to connect MC nodes in a multicast group by using two algorithms, namely, the Pre-computing Minimum Cost
(PMC) tree algorithm and the Pre-computing Shortest Path (PSP) tree algorithm. System performance of the proposed MPCF MC
node placement algorithm is compared with that of the Normalized Cuts (NC) MC node placement algorithm for both PMC and PSP
multicast routing. Furthermore, simulation results compare PMC and PSP multicast routing based on MPCF and NC node placement
with Re-route-to-Source (RTS), Re-route-to-Any (RTA), Member-First (MF), and Member-Only (MO) multicast routing based on a
light forest for a given multicast session in terms of average number of wavelengths needed, average blocking probability,
and mean maximum transmission delay.
相似文献
Tsung-Ching LinEmail: |
13.
An efficient communication relay placement algorithm for content‐centric wireless mesh networks 下载免费PDF全文
Jin Wang Kejie Lu Shukui Zhang Jianxi Fan Yanqin Zhu Baolei Cheng 《International Journal of Communication Systems》2015,28(2):262-280
In this paper, we investigate a communication relay placement problem to optimize the network throughput in a content‐centric wireless mesh networks (WMN), in which the WMN is enhanced by including a small set of communication relays and a subset of wireless mesh routers serving as storage nodes. Specifically, we first define the communication relay placement problem in content‐centric WMNs. We then model the problem as a mathematical programming and propose a linear programming approach for calculating the achievable network throughput when the positions of communication relays are fixed. Next, to optimally placing the communication relays, we formulate an integer linear programming problem and we develop an efficient near‐optimal approximation algorithm based on linear programming relaxation. Finally, extensive simulation experiments have been conducted, and the results demonstrate the effectiveness of the proposed algorithms. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
14.
The feasibility of multicast-capable-reconfigurable optical add/drop multiplexer (MC-ROADM) based on broadcast-and-select switch is experimentally demonstrated. The MC-ROADM can support unicast connection as well as multicast connection, and can provide directionless switching and low insertion loss in path-through channel. We implement fully-reconfigurable multi-degree MC-ROADM based on wavelength selective switch, and evaluate multicasting performances by fully loading 40 × 10 Gbit/s wavelength division multiplexed (WDM) signals. For unicast and multicast operation, measured spectrum and bit-error-rate (BER) show good uniformity and no power penalty. After 1040 km transmission with 25 dB span loss, the measured BER is higher than forward-error-correction (FEC) limit for BER of 10−15. 相似文献
15.
16.
This paper provides an overview of p-cycle based optical multicast protection approaches for link failure recovery, combined node and link failure recovery, and source failure recovery on top of combined node and link failure recovery. We discuss several recently proposed p-cycle based optical multicast protection approaches, including the link-protecting p-cycle based optical multicast protection approach, the tree-protecting p-cycle based optical multicast protection approach, node-and-link protecting p-cycle based optical multicast protection approach, and flow p-cycle based optical multicast protection approach. They outperform other existing optical multicast protection approaches in both capacity efficiency and recovery speed. 相似文献
17.
18.
In this article we study the multicast routing problem in all-optical WDM networks under the spare light splitting constraint.
To implement a multicast session, several light-trees may have to be used due to the limited fanouts of network nodes. Although
many multicast routing algorithms have been proposed in order to reduce the total number of wavelength channels used (total
cost) for a multicast session, the maximum number of wavelengths required in one fiber link (link stress) and the end-to-end
delay are two parameters which are not always taken into consideration. It is known that the shortest path tree (SPT) results
in the optimal end-to-end delay, but it can not be employed directly for multicast routing in sparse light splitting WDM networks.
Hence, we propose a novel wavelength routing algorithm which tries to avoid the multicast incapable branching nodes (MIBs,
branching nodes without splitting capability) in the shortest-path-based multicast tree to diminish the link stress. Good
parts of the shortest-path-tree are retained by the algorithm to reduce the end-to-end delay. The algorithm consists of tree
steps: (1) a DijkstraPro algorithm with priority assignment and node adoption is introduced to produce a SPT with up to 38%
fewer MIB nodes in the NSF topology and 46% fewer MIB nodes in the USA Longhaul topology, (2) critical articulation and deepest
branch heuristics are used to process the MIB nodes, (3) a distance-based light-tree reconnection algorithm is proposed to
create the multicast light-trees. Extensive simulations demonstrate the algorithm’s efficiency in terms of link stress and
end-to-end delay. 相似文献
19.
20.
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