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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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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
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A Study of Broadband Intelligent Network Implementing Video Conference and Multicast Routing Algorithm 相似文献
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With the rapid growth of the network traffic,the elastic optical network (EON) has been proposed as a promising solution due to its high spectrum efficiency and flexible bandwidth provision.Meanwhile,multicast routing and spectrum allocation,and the survivability of the network become more challenging than that in the conventional optical network.The routing for multicast traffic and its protection algorithm in EON was investigated.An integer linear programming (ILP) formulation with the objective to minimize total spectrum consumption was presented.In addition,a heuristic algorithm called multicast sub-tree protection algorithm (MSPA) to achieve sufficient protection and satisfy resources savings was designed.The simulation results demonstrate that comparing with the traditional multicast routing and protection algorithm,MSPA performs well in improving the blocking probability and the spectrum utilization of the network. 相似文献
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如何在缺乏全局信息的条件下构建安全可靠的组 播树,是智能光网络分域管理后引入的一个新问 题。针对此问题,通过建立新型的多域智能光网络超图模型,在考虑物理或攻击损伤的约束 条件下,利用 基于超路径的域间超树构建方法,结合K最短路径策略,提出了 一种基于超图模型的多域ASON损伤感知 组播路由算法,并进行了实例分析。本文算法在完成多域组播路由建立与波长分配的同时, 具有较低的时间复杂度。通过测量K值、组播规 模、波长数量及分配策略、域数量对网络平均连接阻塞率的影响,实验结果表明,本文算法 是有效的且取得了较好的阻塞性能,同时建议多域ASON组播规模大小应与域的数量保持一 定的比例均衡。 相似文献
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Multicast is a vital operation in both broad-band integrated services digital networks (BISDN) and scalable parallel computers. We look into the issue of supporting multicast in the widely used three-stage Clos network or υ(m, n, r) network. Previous work has shown that a nonblocking υ(m, n, r) multicast network requires a much higher network cost than a υ(m, n, r) permutation network. However, little has been known on the blocking behavior of the υ(m, n, r) multicast network with only a comparable network cost to a permutation network. We first develop an analytical model for the blocking probability of the υ(m, n, r) multicast network and then study the blocking behavior of the network under various routing control strategies through simulations. Our analytical and simulation results show that a υ(m, n, r) network with a small number of middle switches m, such as m=n+c or dn, where c and d are small constants, is almost nonblocking for multicast connections, although theoretically it requires m⩾Θ(n(log r/log log r)) to achieve nonblocking for multicast connections. We also demonstrate that routing control strategies are effective for reducing the blocking probability of the multicast network. The best routing control strategy can provide a factor of two to three performance improvement over random routing. The results indicate that a υ(m, n, r) network with a comparable cost to a permutation network can provide cost-effective support for multicast communication 相似文献
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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
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Currently,multicast survivability in optical network obtains more attention.This paper focuses on the field of multicast grooming shared protection in green optical network and designs a novel auxiliary graph and a shared matrix to address the survivable multicast resource consumption.This paper also proposes a new heuristic called Green Multicast Grooming algorithm based on spanning path Cross-Shared protection(GMGCSP),in which network reliability,energy efficiency and resource utilization are jointly considered.Simulation results testify that,compared to other algorithms,the proposed GMG-CSP not only has lower blocking probability and higher bandwidth utilization ratio,but also saves more energy. 相似文献
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The wavelength assignment with multiple multicast requests in fixed routing WDM network is studied. A new multicast dynamic wavelength assignment algorithm is presented based on matching degree. First, the wavelength matching degree between available wavelengths and multicast routing trees is introduced into the algorithm. Then, the wave.length assignment is translated into the maximum weight matching in bipartite graph, and this matching problem is solved by using an extended Kuhn-Munkres algorithm. The simulation results prove that the overall optimal wavelength assignment scheme is obtained in polynomial time. At the same time, the proposed algorithm can reduce the connecting blocking probability and" improve the system resource utilization. 相似文献
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多点并行蚁群搜索在多限制动态组播中的应用研究 总被引:2,自引:0,他引:2
随着Internet的快速发展和商用化的提高,多媒体组播通信越来越引起人们的广泛关注。以往的研究成果大多是集中在固定的多点模型上,而许多服务是无法应用这种应用模型的。本文在充分研究以往组播通信的基础上,针对没有固定组成员的动态组播通信提出了运用蚁群算法进行并行寻路的算法模型。同时,为了加快蚁群算法的收敛速度,对该算法进行了一定的改进。仿真试验表明,该算法是一种有效的适应动态组成员的组播路由算法,具有一定的实用价值。 相似文献
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多播通信这种兼顾了广播通信与单播通信两者优点的通信模式,已经被越来越多地应用于平面网络业务之中。首先讨论了面向源节点的多播路由策略。在分析传统多播路由算法中最佳链路选择函数的基础上,提出了一个新的最佳路由模型和QMRI算法,该算法成功地解决了网络中多播节点动态变化时的QOS路由选择问题。 相似文献
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An Ant-Based Approach for Dynamic RWA in Optical WDM Networks 总被引:1,自引:0,他引:1
In this paper, we propose a new ant-based algorithm for the dynamic routing and wavelength assignment (RWA) problem in optical
WDM networks under the wavelength continuity constraint. Unlike conventional approaches, which usually require centralized
global network information, our new RWA algorithm constructs the routing solution in a distributed manner by means of cooperative
ants. To facilitate the ants’ foraging task, we adopt in our algorithm a probabilistic routing table structure for route selection.
The new algorithm is highly adaptive in that it always keeps a suitable number of ants in the network to cooperatively explore
the network states and continuously update the routing tables, so that the route for a connection request can be determined
promptly by the current states of routing tables with only a small setup delay. Some new schemes for path scoring and path
searching are also proposed to enhance the performance of our ant-based algorithm. Extensive simulation results upon three
typical network topologies indicate that the proposed algorithm has a very good adaptability to traffic variations and it
outperforms both the fixed routing algorithm and the promising fixed–alternate routing algorithm in terms of blocking probability.
The ability to guarantee both a low blocking probability and a small setup delay makes the new ant-based routing algorithm
very attractive for both the optical circuit switching networks and future optical burst switching networks 相似文献
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A protocol for scalable loop-free multicast routing 总被引:3,自引:0,他引:3
Parsa M. Garcia-Luna-Aceves J.J. 《Selected Areas in Communications, IEEE Journal on》1997,15(3):316-331
In network multimedia applications such as multiparty teleconferencing, users often need to send the same information to several (but not necessarily all) other users. To manage such one-to-many or many-to-many communication efficiently in wide-area internetworks, it is imperative to support and perform multicast routing. Multicast routing sends a single copy of a message from a source to multiple receivers over a communication link that is shared by the paths to the receivers. Loop-freedom is an especially important consideration in multicasting because applications using multicasting tend to be multimedia and bandwidth intensive, and loops in multicast routing duplicate looping packets. We present and verify a new multicast routing protocol, called multicast Internet protocol (MIP), which offers a simple and flexible approach to constructing both group-shared and shortest-paths multicast trees. MIP can be sender-initiated or receiver-initiated or both; therefore, it can be tailored to the particular nature of an application's group dynamics and size. MIP is independent of the underlying unicast routing algorithms used. MIP is robust and adapts under dynamic network conditions (topology or link cost changes) to maintain loop-free multicast routing. Under stable network conditions, MIP has no maintenance or control message overhead. We prove that MIP is loop-free at every instant, and that it is deadlock-free and obtains multicast routing trees within a finite time after the occurrence of an arbitrary sequence of topology or unicast changes 相似文献
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Ad Hoc网络是一个多跳的无基础设施网络,本文在分析Ad Hoc网络自身特点的基础上,引入了一种多组播业务并存的K重组播网络,这种网络相对传统的组播网络具有节省系统开销,降低能量消耗的优点.文中对K重组播网络中的节点连接度的不同变化情况进行了理论上的详细研究,并在此基础上设计了一种适用于K重组播网络的负载均衡路由算法.仿真结果表明该路由算法拥塞控制性能良好,并能显著提高组播业务的稳定性.本文提出的这种K重组播网络能够广泛的应用于许多实际通信场合. 相似文献