共查询到20条相似文献,搜索用时 62 毫秒
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针对移动组播接入点切换造成的组播树频繁重建问题,本文提出了基于移动频率的区域代理选择方法。整个无线网络被划分为不同的区域,在某一区域内,选择移动频率最小的节点作为该区域的组播代理,为移动网络内该区域的节点提供组播服务。实验证明,该方法有效减少了因节点移动而造成的组播树重构频率。 相似文献
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一种基于移动预测的分层移动组播协议 总被引:1,自引:0,他引:1
组播通信有效地节约了网络资源,在无线移动网络环境中引入组播有着非常重要的意义。论文简要分析了现有移动组播协议,提出了一种新的基于移动预测的分层移动组播方案。仿真与分析表明,该协议组播树重构频率低,子网切换延迟小,可减少组播包的丢失,减少协议开销,优化组播包的传输路径。 相似文献
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特定源组播(SSM)是现在应用最广泛的组播模型。随着无线网络的快速发展,移动用户不断增加,移动环境为越来越多的用户提供有限的、共享的带宽,这样的现实更加重了网络对组播服务的需要。然而,特定源组播(SSM)对组播源移动的支持仍然是一个有待解决的问题。本文将针对组播树修改协议(TM)进行分析和改进,进一步完善组播树修改协议过程。 相似文献
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提出的基于分区的移动组播算法旨在解决移动节点远离本地网络且持续快速运动情况下的组播重构开销过大的问题,通过将网络划分成不同的区域并指定一个区域代表,降低了组播树重构频率。仿真结果表明,此算法较之FHSR算法在网络利用率及组播重构开销方面有更好的性能。 相似文献
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Distributed dynamic mobile multicast 总被引:1,自引:0,他引:1
Yong CuiAuthor Vitae Sajal K. DasAuthor Vitae 《Journal of Parallel and Distributed Computing》2011,71(9):1215-1224
Traditional mobile multicast schemes have either high multicast tree reconfiguration cost or high packet delivery cost. The former affects service disruption time while the latter affects packet delivery delay. Although existing region-based mobile multicast schemes offer a trade-off between two costs to some extent, most of them do not determine the size of the service range, which is critical to network performance. In this paper, we propose a novel approach, called Distributed Dynamic Mobile Multicast (D2M2), to dynamically determine the optimal service range according to the mobility and service characteristics of a user. We derive an analytical model to formulate the costs of multicast tree reconfiguration and multicast packet delivery. The model is based on a Markov chain that analyzes a mobile node’s movement in a 2D mesh network. As the complexity of computing steady probability is high, we aggregate the Markov states by leveraging mobility symmetry. Simulation shows that the network performance is enhanced through D2M2. 相似文献
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Wireless mesh networks (WMNs) are one of key technologies for next generation wireless networks. In this paper, we propose a heuristic channel assignment algorithm with weight awareness to support mobile multicast in WMNs. To enhance network throughput, our algorithm is based on the path forwarding weight to perform channel assignment. In addition to non-overlapping channels, partially-overlapping channels are also used in channel assignment. To fully exploit all available channels in channel assignment, we devise a new channel selection metric to consider the channel separation and the distance between nodes. In mobile multicast, the multicast tree structure cannot be fixed due to receiver (multicast member) mobility. The change of the multicast tree structure will result in channel re-assignment. The proposed algorithm is based on a critical-event driven manner to reduce the times of channel re-assignment as much as possible. Finally, we perform simulation experiments to show the effectiveness of the proposed channel assignment algorithm. 相似文献
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随着大量新型的多媒体在高性能网络、移动网络及Internet中的应用,满足QoS约束的多播路由协议越来越重要.针对目前多播路由协议无法同时满足可扩展性和高成功率,提出了一种新的以移动代理为基础的QoS多播路由协议(MAQMR).该方法允许多播协议在移动代理间实现并在代理所访问的每个结点得到动态应用.不同于单播路由,移动代理以并行和分布形式协作方式来构建多播树,同时使消息开销最小化并满足QoS要求. 相似文献
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分析了基于数字化变电站内交换机、监控主机、测控装置、保护装置、合并单元的IGMP Snooping和GMRP动态组播实际应用环境,描述了模型中各模块的功能,比较了两种动态组播模型的应用环境和优缺点.制作了基于WinPcap的动态组播软件测试包,向交换机发送模拟的IGMP Snooping和GMRP操作报文,可以对IGMP Snooping和GMRP两种协议进行测试,并且给出了各自的测试用例.测试结果对于提高数字化电力信息以太网络的安全可靠运行有重要参考意义.说明使用WinPcap来进行IGMP Snooping和GMRP报文收发可以较好地测试数字化变电站的动态组播性能. 相似文献
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网络流媒体等新型应用的快速发展对路由器具备组播功能提出了迫切需求.针对如何在基于网络处理器的路由器中高效地实现组播协议进行了研究.在路由器标准功能软件基础上实施扩展,提出了IGMP和PIM等组播协议实现的软件结构,利用网络处理器灵活可编程性与高性能的优点,对其关键技术进行了设计和实现.协议测试结果表明,该路由器组播协议系统运行效果良好,最后,展望了IP组播技术发展. 相似文献
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Location aware, dependable multicast for mobile ad hoc networks 总被引:1,自引:0,他引:1
This paper introduces dynamic source multicast (DSM), a new protocol for multi-hop wireless (i.e., ad hoc) networks for the multicast of a data packet from a source node to a group of mobile nodes in the network. The protocol assumes that, through the use of positioning system devices, each node knows its own geographic location and the current (global) time, and it is able to efficiently spread these measures to all other nodes. When a packet is to be multicast, the source node first locally computes a snapshot of the complete network topology from the collected node measures. A Steiner (i.e., multicast) tree for the addressed multicast group is then computed locally based on the snapshot, rather than maintained in a distributed manner. The resulting Steiner tree is then optimally encoded by using its unique Pr
u" height="11" width="9">fer sequence and is included in the packet header as in, and extending the length of the header by no more than, the header of packets in source routing (unicast) techniques. We show that all the local computations are executed in polynomial time. More specifically, the time complexity of the local operation of finding a Steiner tree, and the encoding/decoding procedures of the related Prüfer sequence, is proven to be O(n2), where n is the number of nodes in the network. The protocol has been simulated in ad hoc networks with 30 and 60 nodes and with different multicast group sizes. We show that DSM delivers packets to all the nodes in a destination group in more than 90% of the cases. Furthermore, compared to flooding, DSM achieves improvements of up to 50% on multicast completion delay. 相似文献
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Improving routing distance for geographic multicast with Fermat points in mobile ad hoc networks 总被引:1,自引:0,他引:1
In mobile ad hoc networks (MANETs), each node has the ability to transmit, receive, and route packets, and also moves through the field either randomly or in accordance with a pre-planned route. For enhancing the performance of MANETs, reducing the routing distance is a primary concern. For either ad hoc or static networks, the problem of minimizing the overall routing distance during multicasting is NP-complete. Therefore, it is difficult to determine an optimal solution. This paper presents an efficient geographic multicast protocol, designated as GMFP, based on the use of Fermat points. The objective of GMFP is to improve the overall routing distance for multicast tasks. Through a series of simulations, it is shown that GMFP outperforms the conventional Position-Based Multicast protocol and FERMA protocol in terms of the total routing distance, the packet transmission delay, the packet delivery ratio, and the node energy consumption. The performance improvements provided by GMFP are apparent as the scale of the network topology increases. 相似文献
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移动自组织网络环境中,选择稳定路由可以提高数据传输率并能有效降低控制信息减少网络拥塞。根据无线自组网的特点,提出了一种新颖的基于信号强度评价链路稳定性的方法,并且基于此方法构建组播路由协议。协议中节点能够根据信号强度预估链路稳定性,选择稳定路由,及时发现修复即将断开的链路。仿真结果表明,协议可以明显提高数据传输率,并且控制开销较低。 相似文献