An Efficient Multicast Routing Protocol in Wireless Mobile Networks

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.     

On-Demand Multicast Routing Protocol in Multihop Wireless Mobile Networks

An ad hoc network is a dynamically reconfigurable wireless network with no fixed infrastructure or central administration. Each host is mobile and must act as a router. Routing and multicasting protocols in ad hoc networks are faced with the challenge of delivering data to destinations through multihop routes in the presence of node movements and topology changes. This paper presents the On-Demand Multicast Routing Protocol (ODMRP) for wireless mobile ad hoc networks. ODMRP is a mesh-based, rather than a conventional tree-based, multicast scheme and uses a forwarding group concept; only a subset of nodes forwards the multicast packets via scoped flooding. It applies on-demand procedures to dynamically build routes and maintain multicast group membership. ODMRP is well suited for ad hoc wireless networks with mobile hosts where bandwidth is limited, topology changes frequently, and power is constrained. We evaluate ODMRP performance with other multicast protocols proposed for ad hoc networks via extensive and detailed simulation.     

一种适用于动态/移动环境的新的组播协议

组播协议由于能够有效的利用网络带宽并降低服务器的负担因而受到广泛的关注.其中的共享树组播协议由于具有良好的扩展性而得到更多的支持,然而目前的共享树组播协议在动态移动环境中的性能很差,一些改进协议(单核移动协议)虽然可以很好的提高原有协议的性能但是所需要的额外开销很大.针对这种情况,本文提出了一种新的共享树组播协议-动态多核协议,该协议能够根据组播成员的分布动态的渐进的调整组播树的形状,从而能够在低开销的情况下为移动用户提供良好的性能.计算机仿真和数学分析都表明动态多核协议要明显优于共享树组播协议和单核移动协议.     

GMZRP: Geography-aided Multicast Zone Routing Protocol in Mobile Ad Hoc Networks

This paper presents the design and evaluation of a highly efficient on-demand multicast routing protocol for mobile ad hoc networks (MANETs). The protocol, called Geography-aided Multicast Zone Routing Protocol (GMZRP), eliminates as much as possible duplicate route queries by using a simple yet effective strategy for propagating the multicast route request (MRREQ) packets. GMZRP is the first hybrid multicast protocol taking the advantages of both topological routing and geographical routing. It partitions the network coverage area into small zones and guarantees that each geographic zone is queried only once. GMZRP maintains a multicast forwarding tree at two levels of granularities, i.e., the zone granularity and the node granularity. By doing this, it can easily handle route breakage since the zone level information can help recover the link failure at the node level. The results of the performance evaluation of GMZRP using simulation show that, comparing with the well-known multicast protocol ODMRP (On-Demand Multicast Routing Protocol), GMZRP has much lower protocol overhead in terms of query packets and, meanwhile, achieves competing packet delivery ratio and shorter delivery latency.

基于移动IP的组播协议

总结了目前在移动IP网络中组播领域的主要算法,分析比较了它们的特点和性能,概括了其中的主要研究问题,并对该领域未来的研究进行了展望.     

基于IPv4的可靠移动组播技术

移动组播技术是近几年来无线互联网领域的一个研究热点,其相当一部分应用要求移动环境下也能提供相当于有线链路的可靠性。但是移动环境下的突出特点就是链路差错率高,组播成员位置动态变化,这给移动组播尤其是可靠移动组播提出了很大的挑战。基于IPv4的可靠移动组播算法具有两种不同的设计思想,其中一部分算法是针对现有的移动组播算法存在的问题,进行可靠性方面的改进,另一部分算法是专门用于实现可靠移动组播的,它们大都引入了新的功能实体来保证可靠性。     

A Domain-Based Routing Protocol for SSM Source Mobility in Mobile IPv6 Networks

In Mobile IP, the signaling traffic overhead will be too high since the new Care-of-Address (CoA) of the mobile node (MN) is registered all the way with the home agent (HA) whenever the MN has moved into a new foreign network. To complement Mobile IP in better handling local movement, several IP micro protocols have been proposed. These protocols introduce a hierarchical mobility management scheme, which divides the mobility into micro mobility and macro mobility according to whether the host's movement is intra-domain or inter-domain. Thus, the requirements on performance and flexibility are achieved, especially for frequently moving hosts. This paper introduces a routing protocol for multicast source mobility on the basis of the hierarchical mobile management scheme, which provides a unified global architecture for both uni- and multicast routing in mobile networks. The implementation of multicast services adopts an improved SSM (Source Specific Multicast) model, which combines the advantages of the existing protocols in scalability and mobility transparency. Simulation results show that the proposed protocol has better performance than the existing routing protocols for SSM source mobility.     

链路可靠的无线传感器网络组播路由协议

在无线传感器网络实际应用中,组播正在发挥着越来越重要的作用.但由于能量等多方面的因素,使得为无线传感器网络设计一个有效的组播路由是非常困难的.针对无线传感器网络中节点的能量限制,通过寻求节点间最短路径,提出一种能量有效的链路可靠组播路由协议(RLMR).该协议充分考虑到网络中节点的能耗因素和两节点间的链路可靠性等,通过对这两个因素的综合考虑,让能量较多并且以发送节点更靠近的节点承担更多传输任务的方式,为数据流优化路由选择,均衡无线传感器网络节点的能量消耗,以延长网络的生存时间.仿真结果证明了RLMR的有效性和可靠性.     

移动IP组播方案

目前的移动IP方案没有较好解决对组播的支持。文中分析了当前移动IP组播的几种方案以及存在的问题，比较了各自的优缺点，提出了一种改进的基于移动IP的移动主机组播技术方案，并与其他方案做了比较。     

移动Ad Hoc网络组播路由协议的研究综述

移动Ad Hoc网络是一个自组织、移动节点通过无线链路组成的动态拓扑变化的网络。由于网络规模小、无基础设施构建快速等特点,从而广泛应用于灾难救助、临时会议、战场指挥等场合。这些应用都涉及到移动Ad Hoc对组播的支持,因此,随着网络应用规模的增长,移动Ad Hoc网络对组播的支持成为一个重要的研究课题。本文对目前的组播路由机制进行了分类和研究,详细描述和比较了这些移动Ad Hoc网络组播路由协议,为组播路由协议和算法进一步的研究提出了新的课题。     

一种节省能量的移动Ad Hoc网络组播选路协议

鉴于现有基于网孔的移动Ad Hoc网络组播选路协议都滑考虑如何有效使用电池能量的问题，本文提出了一种节省能量组播选路协议（E^2MRP),E^2MRP协议的两个主要特征是：（1）在创建和维护中继组（RG）的过程中交替采用分组平均能量消耗最少和最大节点花费最小两种标准，（2）采用基于图的组播结构，本文通过仿真分析大大降低了节点的能量消耗，特别是在节移动性较低，组播成员较少时更是如此。     

Integrated Mobility Management Methods for Mobile IP and SIP in IP based Wireless Data Networks

With developments in voice over IP (VoIP), IP-based wireless data networks and their application services have received increased attention. While multimedia applications of mobile nodes are served by Session Initiation Protocol (SIP) as a signaling protocol, the mobility of mobile nodes may be supported via Mobile IP protocol. For a mobile node that uses both Mobile IP and SIP, there is a severe redundant registration overhead because the mobile node has to make location registration separately to a home agent for Mobile IP and to a home registrar for SIP, respectively. Therefore, we propose two new schemes that integrate mobility management functionality in Mobile IP and SIP. We show performance comparisons among the previous method, which makes separate registration for Mobile IP and SIP without integration, and our two integrated methods. Numerical results show that the proposed methods efficiently reduce the amount of signaling messages and delay time related to the idle handoff and the active handoff.     

基于泛洪约束的MANET按需组播路由协议

降低路由控制开销是MANET网络组播路由协议节省节点能量,提高带宽利用率的关键因素之一。本文研究了组播路径近邻节点对路由维护的作用以及链路的连通性,分别提出了一个新的泛k-洪约束算法和一个混合泛洪模式。基于泛k-洪约束算法和混合泛洪模式,提出一个新的按需组播路由协议ODMRP-CF,ODMRP-CF协议通过选择k-路由近邻节点转发泛洪分组来提高泛洪效率。ODMRP-CF协议不仅保持了ODMRP协议所具有的简单,对节点移动鲁棒性好的优点,而且有效地降低了ODMRP-CF协议的控制开销。     

依赖源汇聚点的组播协议

域间组播一直是大范围内部署组播时需要考虑的主要因素。依赖源汇聚点组播是一种基于Chord查找协议的简单有效的域间组播方案，方案中接收者的指定路由器（DR）使用Chord协议获得源RP地址，并加入源RP树。依赖源汇聚点的组播方案是一种域同ASM解决方案；能提供很好的容错性和可扩展性；支持主机移动组播，但不会造成三角路由问题。     

Scalable Multicasting: The Core-Assisted Mesh Protocol

Most of the multicast routing protocols for ad hoc networks today are based on shared or source-based trees; however, keeping a routing tree connected for the purpose of data forwarding may lead to a substantial network overhead. A different approach to multicast routing consists of building a shared mesh for each multicast group. In multicast meshes, data packets can be accepted from any router, as opposed to trees where data packets are only accepted from routers with whom a tree branch has been established. The difference among multicast routing protocols based on meshes is in the method used to build these structures. Some mesh-based protocols require the flooding of sender or receiver announcements over the whole network. This paper presents the Core-Assisted Mesh Protocol, which uses meshes for data forwarding, and avoids flooding by generalizing the notion of core-based trees introduced for internet multicasting. Group members form the mesh of a group by sending join requests to a set of cores. Simulation experiments show that meshes can be used effectively as multicast routing structures without the need for flooding control packets.     

适于低轨卫星IP网络的特定源组播算法

为了解决低轨卫星IP网络中现有特定源组播算法的信道资源浪费问题,本文提出了一套新的特定源组播算法,即基于核心群的特定源组播算法(CSSM)和加权的CSSM算法(w-CSSM).CSSM算法以源节点作为初始核心群,通过核心群和剩余组成员的最短路径方法逐步扩展直至整棵组播树构建完成,所得的树代价最小,从而大大提高了网络的带宽利用率和传输效率.在w-CSSM算法中,加权因子可以自适应调整以适度增大树代价、降低端到端传播时延,以支持某些有严格端到端时延要求的实时组播业务.通过与低轨卫星IP网络中典型特定源组播算法MRA的仿真比较,可以看出CSSM和w-CSSM算法的树代价性能比MRA有较大改善,不过端到端传播时延略高.     

A Reliable Multicast Routing Protocol Based on Recovery Points and FEC in Mobile Ad-hoc Networks

Multicasting is an essential service for mobile ad-hoc networks. A major challenge for multicasting in mobile ad-hoc networks (MANETs) is the unstable forwarding path. This work presents a reliable multicasting protocol for mobile ad-hoc networks. A virtual backbone is used as a shared structure for multiple sessions. A lost packet recovery scheme is developed for reliable packet transmission, called the Recovery Point (RP) scheme. The RP scheme maintains the data packets received from the source for recovering lost packets for its downstream RPs. In addition, we combine the Forward Error Correction (FEC) technology with our RP scheme to enhance the reliability of our RP scheme. A mergence scheme for RP is also proposed to avoid excessive control overhead. Our RP and FEC based scheme can be used to improve the reliability and efficiency of the traditional non-acknowledged multicasting approach. Experiments were conducted to evaluate the proposed multicasting scheme. The results demonstrate that our scheme outperforms other schemes in terms of packet delivery ratio and multicast efficiency. Furthermore, the simulation results also demonstrate that our approach is stable in networks with high mobility.