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1.
针对Ad Hoc网络中带QoS约束的多播路由问题,提出了一种新的结合MAODV多播路由发现方法和粒.子群优化算法的QoS多播路由发现算法。仿真试验显示该算法较好地改进了端到端传输的代价、延时和带宽利用率,能够找到一棵消耗趋于最小、状态稳定的多播路由树。  相似文献   

2.
Ad Hoc网络中一种基于QoS的分布式多播路由算法   总被引:6,自引:0,他引:6  
石坚  邹玲 《通信学报》2003,24(6):60-68
通过分析Ad Hoe网络的特点及基于QoS的多播路由问题,提出了一种新的分布式多播路由算法。实验和分析的结果表明,文中构造的路由方案成功地解决了Ad Hoe网中基于QoS的多播路由问题。当Ad Hoe网络的拓扑结构改变不太快时,本文提出的路由方案不仅满足了实时业务对网络带宽和端到端延时的要求,优化了路由树的代价,而且有效地控制了算法的复杂性并可适用于大规模的网络中。  相似文献   

3.
基于时延约束的改进型实时QoS多播路由算法   总被引:1,自引:1,他引:0  
多播技术是将特定数据选择性地传送至多个客户端的方法,因而其服务质量是评价其优劣的关键.结合FLSPT算法和贪婪法思想,提出一种基于时延约束的改进型实时QoS多播路由算法,它利用启发式策略,使得节点在多播树时能满足时延约束的条件下建立最小代价路径.测试结果表明,采用该算法可获得较小的端到端时延,能改善网络服务质量,适用于成员数目变化频繁的多播应用.  相似文献   

4.
网络通信中的多播分为单树多播和成组多播。本文研究具有带宽约束的静肪多播路由问题,分别建立了基于带宽约束的单树多播和成组多播的数学并构造了相应的路由算法,利用此算法可使成组多播达到全局最优。  相似文献   

5.
无线Mesh网络多播路由是无线路由必须解决的关键技术。部分研究者对网络资源和服务质量(QoS)进行研究,提出了建立最短路径树、最小开销树、负载感知、信道分配多播等多播算法;有的算法考虑链路可靠性,建立备用路径。将结合网络资源和可靠性对多播路由算法进行研究,提出了建立可靠多播树(RT,Reliable Tree)的多播路由算法:可靠多播树是一个多树结构,由一棵首选多播树和一棵多径树构成,多径树提供可靠多路径,以提高网络吞吐量。  相似文献   

6.
随着计算机网络的不断发展,大量多媒体应用要求网络具有满足QoS约束的多播功能.应用多播的关键是确定有效的多播路由,即求解最优Steiner树.目前提出的大部分都是集中式的或本质上是集中式的启发式算法,关于分布式算法的研究还比较少.本文提出了一种基于蚁群算法的分布式多播路由算法.该算法在源节点不掌握整个网络信息的情况下,利用网络的局部启发式信息和蚂蚁留下的信息素建立最优的多播路由.结合多播路由问题的特点,对算法进行了改进,使算法的收敛速度和解的质量都得到了较大的提高.仿真实验结果验证了该算法的有效性.  相似文献   

7.
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   

8.
叶必海 《信息通信》2010,(1):53-55,76
提出了一个改进的稀疏分光器配置约束下的改进算法。在稀疏分光器配置约束下,多播路由不再是图论中”树”的形状,多播路由可能存在逻辑圈。现有的多播路由算法没有考虑这个特点,改进对此算法作了一下改进,通过仿真证明改进算法提高了网络性能。  相似文献   

9.
提出了一个改进的稀疏分光器配置约束下的改进算法。在稀疏分光器配置约柬下,多播路由不再是图论中“树”的形状,多播路由可能存在逻辑圈。现有的多播路由算法没有考虑这个特点,对此算法作了一下改进,通过仿真证明改进算法提高了网络性能。  相似文献   

10.
张谞  吴慧中 《通信学报》2007,28(11):103-110
虚拟空间会议(VST,virtual space teleconferencing)是具有广泛应用前景的一种新兴CSCW工具,在当前没有IP多播支持以及大多数端用户访问带宽有限的互联网条件下,实现互联网上的VST应用缺乏有效的通信机制。针对这一问题,提出了一种感知驱动的VST多源应用层多播方法ESMVST,该方法采用了网优先的集中式策略,重点研究了ESMVST方法中的路由模型VSTMMR,提出一种启发式路由算法MDMM。实验结果表明MDMM算法有效降低了算法的拒绝率和数据分发树的最大延迟,ESMVST方法实用可行。  相似文献   

11.
基于GMPLS控制平面的ASON组播   总被引:3,自引:1,他引:2  
阐述了利用自动交换光网络(ASON)实现组播的意义,分析了ASON组播的GMPLS信令协议、路由协议,给出了通过改进ASON现有技术实现组播的可行方案,包括信令过程和路由算法,得出结论并对ASON组播的前景作出展望。  相似文献   

12.
Group communication services typically generate large multicast data streams. Delivering such massive data streams to the end system nodes at the edge of the Internet has been a challenging problem in terms of high stress on the network links and high demand on network resources and routing node capacities. Most of existing research has been dedicated on geo-distance based routing with various optimizations to alleviate the performance impact on geo-distance based routing due to unpredictable network dynamics. Most representative techniques are targeted at reducing the delivery path length or optimizing routing path by utilizing network locality. In this paper, we identify the inefficiency of geo-distance based routing protocols in many existing multicast overlay networks in terms of both resource utilization and group communication efficiency. To address this issue, we develop a utility-based routing scheme (UDR) that can provide efficient group communication services in a decentralized geographical overlay network. Our approach makes three unique contributions. First, we introduce a utility function to refine the geo-distance based routing in such a way that the routing path selection can carefully incorporate both geo-distance based metric and the network latency. Second, we enhance our utility driven routing scheme with self-adaptive capability by considering the nodes?? state and network density. Thus, nodes in the multicast network can dynamically accommodate the changes of network conditions based solely on their local knowledge about the network. Third, we devise a suite of optimization techniques to minimize the maintenance cost and computational complexity of our self-adaptive and utility-drive routing scheme. We evaluate our approach through extensive experiments based on a realistic network topology model and show that the UDR method is highly scalable and it effectively enhances the multicast delivery efficiency for large scale group communication services compared to existing geo-distance based routing protocols.  相似文献   

13.
有时延及时延差别约束的最小代价组播路由问题   总被引:6,自引:0,他引:6  
郭伟  席裕庚 《通信学报》2001,22(6):13-20
本文把有时延、时延差别约束的组播路由问题提到优化的层次上,提出了有时延、时延差别约束的最小代价组播路由优化问题,并证明此问题是NP-complete问题。继而提出了一种基于动态罚函数法的启发式遗传算法以及解该问题,并分析了算法的复杂度。仿真表明,本文算法是有效的、稳定的。在满足两种约束的情况下,能够使网络代价优化。  相似文献   

14.
Multicasting is an effective way to provide group communication. In mobile ad hoc networks (MANETs), multicasting can support a wide variety of applications that are characterized by a close degree of collaboration. Since MANETs exhibit severe resource constraints such as battery power, limited bandwidth, dynamic network topology and lack of centralized administration, multicasting in MANETs become complex. The existing multicast routing protocols concentrate more on quality of service parameters like end‐to‐end delay, jitter, bandwidth and power. They do not stress on the scalability factor of the multicast. In this paper, we address the problem of multicast scalability and propose an efficient scalable multicast routing protocol called ‘Power Aware Scalable Multicast Routing Protocol (PASMRP)’ for MANETs. PASMRP uses the concept of class of service with three priority levels and local re‐routing to provide scalability. The protocol also ensures fair utilization of the resources among the nodes through re‐routing and hence the lifetime of the network is increased. The protocol has been simulated and the results show that PASMRP has better scalability and enhanced lifetime than the existing multicast routing protocols. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

15.
基于延时及带宽约束的组播路由算法   总被引:1,自引:0,他引:1  
石坚  董天临  邹玲  杜婷 《通信学报》2001,22(7):48-53
本文分析了网络中基于延时和带宽受限的组播路由优化问题,提出了一种新的启发式算法,并进行了实验和分析。文中构造的路由方案成功地解决了当网络中存在多组组播通信时的QoS路由选择问题。此方案不仅保证了组播业务所需的带宽、端到端延时、减小了丢包率,而且有效地控制了算法的复杂性并可适用于大规模的网络中。  相似文献   

16.
Multicast routing research efforts have mostly focused on supporting the host-group model in which multicast packets are addressed to a host (or multicast) group. Another multicast routing approach uses multi-destination addressing, where a multicast packet carries a list of the unique (unicast) addresses of all the group members. This form of routing can be accomplished using limited or no additional state beyond the existing unicast routing tables. It, therefore, scales well with the number of multicast sessions but does not scale well with the size of the multicast group and, in fact, requires the size of the multicast group to be below a certain threshold. In this paper, we envision a future scenario in which both host-group and multi-destination addressing routing approaches coexist within the Internet. We develop a dynamic routing context for this future scenario wherein a multicast session can adapt among different routing configurations depending on the number of multicast group members and how this number changes over time. We consider three routing options: (1) A single multi-destination addressed flow – suitable for small-group sessions, (2) multiple multi-destination addressed flows – suitable for medium-group sessions and (3) a single host-group addressed flow – suitable for large-group sessions. For multicast sessions that vary in group membership over time, different routing protocols may be best at different points in time. Our work is concerned with the development and evaluation of protocols that allow a multicast session to dynamically switch among these three routing options as the size of the session changes.  相似文献   

17.
动态QoS多播路由协议   总被引:24,自引:0,他引:24       下载免费PDF全文
李腊元  李春林 《电子学报》2003,31(9):1345-1350
本文主要研讨了具有QoS约束的动态多播路由问题.文中描述了一种适用于QoS多播路由的网络模型,提出了一种动态QoS多播路由协议(DQMRP),该协议能操作在单播路由协议的顶层,它只要求网络链路(或节点)的局部状态信息,不需要维护全局状态信息.DQMRP可有效地减少构造一棵多播树的开销,多播组成员可动态地加入/退出多播会晤.该协议可搜索多条可行树枝,并能选择一条最优(或近优)树枝将新成员连接到多播树.文中给出了DQMRP的正确性证明和复杂性分析,并通过仿真实验验证了该协议的可用性和有效性.  相似文献   

18.
This paper studies the multicast routing problem in the multi‐hop wireless network. We exploit topology control to put forward a multicast routing algorithm with minimum energy consumption. First, network nodes are classified as different clusters. Then, the end‐to‐end multicast routing is appropriately built by using the cooperation among clusters and in each cluster and by minimizing the energy consumption. Unlike previous methods, we employ the appropriate cooperation among/in clusters and the optimal cross‐layer design to attain the information from the different layers and the different nodes. In a result, on the basis of the information, the needed clusters of nodes are correctly created. This is helpful to avoid clustering blindly network nodes and to reduce computational overheads. Simulation results show that the proposed algorithm is promising and effective. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

19.
A protocol for scalable loop-free multicast routing   总被引:3,自引:0,他引:3  
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   

20.
Delay-Tolerant Networks (DTNs) are special types of network environments that are subject to delays and disruptions. Most research efforts on the DTN routing problem are focused on unicast routing but not multicast routing. Moreover existing DTN multicasting approaches are not efficient and flexible. In this paper, we propose a new multicast routing approach which can not only achieve a high delivery rate but also adapt to network conditions. Most importantly, our proposed approach need not maintain group membership. In other words, any interested users can freely join and leave any multicast groups, and this feature suitably fits into DTN environments.  相似文献   

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