共查询到20条相似文献,搜索用时 156 毫秒
1.
2.
移动自组网是无中心、自组织、可快速展开、可移动的对等式网络,组播作为群组服务在移动自组网中应用广泛。移动自组网具有节点移动频繁、能源和带宽有限等特点,它要求组播协议能在节点频繁移动下具备良好的健壮性,传统的组播协议已不适用。文章介绍了移动自组网组播路由协议,描述了几种组播路由协议的基本运行过程,并对其性能进行了分析和比较,最后论述了组播协议在能源、安全、组播服务(QOS)、利用位置信息等方向的应用前景及面临的问题。 相似文献
3.
组播通信有效地节约了网络资源,在资源受限的无线网络环境中引入组播有着非常重要的意义。本文分析了MAODV组播路由协议的路由机制,用NS2仿真分析了在不同组规模情况下网络的性能。仿真结果表明该组播协议减少了开销、降低了时延,可以有效地支持无线网络中的组播应用。 相似文献
4.
组播是一种被广泛应用的通信技术.组播源认证是组播安全中的重要问题,特别是在有扰信道中实现组播源认证具有很大的挑战性.该文提出一种基于门限密码的链式组播源认证技术,以解决有扰信道上的组播源认证问题.基于组播源认证的安全需求和Dolev-Yao模型,该文首先给出链式组播源认证的安全假设和安全模型;然后结合Shamir的门限秘密共享技术,设计一种适合于有扰信道的组播源认证协议并进行了安全性分析.对协议的仿真结果表明,该文设计的组播源认证在保证较好的通信性能前提下具有良好的抗丢包能力. 相似文献
5.
一种支持QoS的拓扑自适应动态组播路由算法 总被引:3,自引:0,他引:3
YAM、QoSMIC、DSDMR等一类支持QoS的动态组播路由算法允许组播成员动态地加入和离开,同时为接收方提供多个可选择的组播接入路径,以满足不同应用的QoS需求。但这些算法普遍存在控制信令开销大和结点加入时延长,可扩展性不好等问题。本文在分析这些算法的基础上,提出改进的支持QoS的动态组播路由算法,即拓扑自适应动态组播路由(Topology Adaptive Dynamic Multicast Routing,TADMR)算法。该算法避免了以往算法中大部分盲目的路径搜索,并使结点加入时延不再受限于固定的等待时钟,而与网络拓扑相自适应。性能分析和仿真结果表明,该算法具有较低的控制信令开销和结点加入时延,适用于各种网络规模和群组规模,具有良好的可扩展性。 相似文献
6.
7.
组播技术在有线IP网中已经成熟,其在有线IP网中主要解决组的管理和维护以及组播路由确定等.组播路由确定包括发现上游接口、确定下游接口和管理多播树等.由于移动网络在无线侧具有特定的网络结构、功能实体和无线接口,因此要实现组播必须解决无线终端组的管理和维护、无线寻址等问题,还要在现有的网络结构中增加新的网络单元,对原有的功能实体和接口协议进行修改,实现空口资源的共享,这些是与有线网不同的.实际上,最核心的区别是有线网络终端是固定的,需要根据组播路由协议建立合理的多播树;无线网络终端是移动的,需要根据不断移动的终端的位置,准确地将要广播的内容发送给终端. 相似文献
8.
9.
首先介绍了移动组播面临的问题,并对现有的移动组播算法和协议进行了介绍,对其实现的机制、特点进行了详细分析。针对移动组播面临的问题,提出了一个基于组播代理的移动组播协议ABMoM,并对ABMoM实现原理、组成员管理机制以及移动切换问题的处理方法进行了详细的论述。 相似文献
10.
首先介绍了移动组播面临的问题,并对现有的移动组播算法和协议进行了介绍,对其实现的机制、特点进行了详细分析。针对移动组播面临的问题,提出了一个基于组播代理的移动组播协议ABMoM,并对ABMoM的实现原理、组成员管理机制以及移动切换问题的处理方法进行了详细的论述。 相似文献
11.
An Efficient Multicast Routing Protocol in Wireless Mobile Networks 总被引:11,自引:0,他引:11
Providing multicast service to mobile hosts in wireless mobile networking environments is difficult due to frequent changes of mobile host location and group membership. If a conventional multicast routing protocol is used in wireless mobile networks, several problems may be experienced since existing multicast routing protocols assume static hosts when they construct the multicast delivery tree. To overcome the problems, several multicast routing protocols for mobile hosts have been proposed. Although the protocols solve several problems inherent in multicast routing proposals for static hosts, they still have problems such as non-optimal delivery path, datagram duplication, overheads resulting from frequent reconstruction of a multicast tree, etc. In this paper, we summarize these problems of multicast routing protocols and propose an efficient multicast routing protocol based on IEFT mobile IP in wireless mobile networks. The proposed protocol introduces a multicast agent, where a mobile host receives a tunneled multicast datagram from a multicast agent located in a network close to it or directly from the multicast router in the current network. While receiving a tunneled multicast datagram from a remote multicast agent, the local multicast agent may start multicast join process, which makes the multicast delivery route optimal. The proposed protocol reduces data delivery path length and decreases the amount of duplicate copies of multicast datagrams. We examined and compared the performance of the proposed protocol and existing protocols by simulation under various environments and we got an improved performance over the existing proposals. 相似文献
12.
Mobile ad hoc networks are recognized by their abilities to form, sustain, and deform networks on‐the‐fly without the need for any pre‐established and fixed infrastructures. This wireless multi‐hop technology requires adaptive networking protocols with low control overhead and low power consumption to operate efficiently. Existing research so far are mainly concerned with unicast routing for ad hoc mobile networks. There is a growing interest in supporting multicast communication in an ad hoc mobile environment. In this paper, the associativity‐based ad hoc multicast (ABAM) routing protocol is proposed. The concept of association stability is utilized during multicast tree discovery, selection, and reconfiguration. This allows routes that are long‐lived to be selected, thereby reducing the frequency of route reconstructions. ABAM employs a localized route reconstruction strategy in response to migrations by source, receiver, and tree nodes. It can repair an affected subtree via a single route reconstruction operation. ABAM is robust since the repair can be triggered by a node in the tree or by the migrated node itself. ABAM is also capable of handling multicast group dynamics when mobile hosts decide to join and leave an existing multicast group. Our simulation results reveal that under different mobility scenarios and multicast group size, ABAM has low communication overhead and yields better throughput performance. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
13.
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
14.
Mobile multicast is important for the emerging applications such as mobile video or audio conference and mobile IPTV. Some mobile multicast schemes have been proposed in the past few years, but most of them study the reconstruction ofmulticast delivery tree, and few consider the group membership management for mobile subscribers. In this paper, we propose a new mobile multicast method based on the Two-Hop Multicast Listener Discovery (THMLD) protocol which provides the mobile multicast membership management function by forwarding the traditional MLD messages to its neighboring subnets. To evaluate its performance, we analyze the THMLD and set up the simulation platform to compare it with the several traditional mobile multicast methods. The results show that THMLD can reduce the multicast join time, and the THMLD-based mobile multicast method can reduce the multicast join delay at a cost of increasing additional multicast maintenance cost. 相似文献
15.
Eric Astier Abdelhakim Hafid Sultan Aljahdali 《Wireless Communications and Mobile Computing》2012,12(9):822-836
Mesh‐based multicast routing protocols for mobile ad hoc networks (MANETs) build multiple paths from senders to receivers to deliver packets even in the presence of links breaking. This redundancy results in high reliability/robustness but may significantly increase packet overhead. This paper proposes a mesh‐based multicast protocol, called centered protocol for unified multicasting through announcements (CPUMA), that achieves comparable reliability as existing mesh‐based multicast protocols, however, with significantly much less data overhead. In CPUMA, a distributed core‐selection and maintenance algorithm is used to find the source‐centric center of a shared mesh. We leverage data packets to center the core of each multicast group shared mesh instead of using GPS or any pre‐assignment of cores to groups (the case of existing protocols). The proposed centering scheme allows reducing data packet overhead and creating forwarding paths toward the nearest mesh member instead of the core to reduce latency. We show, via simulations, that CPUMA outperforms existing multicast protocols in terms of data packet overhead, and latency while maintaining a constant or better packet delivery ratio, at the cost of a small increase in control overhead in a few scenarios. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
16.
Protocol Independent Multicast-Sparse Mode is the most widely used multicast routing architecture. It builds a shared distribution tree centered at a rendezvous point and then builds source-specific trees for those sources whose data rate warrants it. Current implementations of the protocol decide on the rendezvous point administratively, which leads to congestion and delays. An attractive solution would be dynamic relocation of the rendezvous point depending on the members of the multicast group. In this paper we present a rendezvous point calculation and relocation mechanism for Protocol Independent Multicast-Sparse Mode. Simulation of the proposed mechanisms is used to demonstrate the effectiveness of the proposals. 相似文献
17.
18.
19.
Many multicast applications, such as video‐on‐demand and video conferencing, desire quality of service (QoS) support from an underlying network. The differentiated services (DiffServ) approach will bring benefits for theses applications. However, difficulties arise while integrating native IP multicasting with DiffServ, such as multicast group states in the core routers and a heterogeneous QoS requirement within the same multicast group. In addition, a missing per‐flow reservation in DiffServ and a dynamic join/leave in the group introduce heavier and uncontrollable traffic in a network. In this paper, we propose a distributed and stateless admission control in the edge routers. We also use a mobile agents‐based approach for dynamic resource availability checking. In this approach, mobile agents act in a parallel and distributed fashion and cooperate with each other in order to construct the multicast tree satisfying the QoS requirements. 相似文献
20.
Shengling Wang Yong Cui Sajal K. Das Jianping Wu 《Wireless Communications and Mobile Computing》2012,12(10):875-890
Traditional mobile multicast schemes have higher multicast tree reconfiguration cost or multicast packet delivery cost. Two costs are very critical because the former affects the service disruption time during handoff while the latter affects the packet delivery delay. Although the range‐based mobile multicast (RBMoM) scheme and its similar schemes offer the trade‐off between two costs to some extent, most of them do not determine the size of service region, which is critical to the network performance. Hence, we propose a dynamic region‐based mobile multicast (DRBMoM) to dynamically determine the optimal service region for reducing the multicast tree reconfiguration and multicast packet delivery costs. DRBMoM provides two versions: (i) the per‐user version, named DRBMoM‐U, and (ii) the aggregate‐users version, named DRBMoM‐A. Two versions have different applicability, which are the complementary technologies for pursuing efficient mobile multicast. Though having different data information and operations, two versions have the same method for finding the optimal service region. To that aim, DRBMoM models the users' mobility with arbitrary movement directional probabilities in 2‐D mesh network using Markov Chain, and predicts the behaviors of foreign agents' (FAs') joining in a multicast group. DRBMoM derives a cost function to formulate the average multicast tree reconfiguration cost and the average multicast packet delivery cost, which is a function of service region. DRBMoM finds the optimal service region that can minimize the cost function. The simulation tests some key parameters of DRBMoM. In addition, the simulation and numerical analyses show the cost in DRBMoM is about 22∼50% of that in RBMoM. At last, the applicability and computational complexity of DRBMoM and its similar scheme are analyzed. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献