移动IP支持组播的技术

组播（Multicast）是指源一次发送的数据报被送到多个目的地，用来支持点到多点和多点到多点的通信。移动IP作为未来Internet的一支主力军，需要支持组播。本文回顾了移动IP和IP组播技术，分析了几种移动IP支持组播的机制，并对这几种机制进行了比较。     

基于移动接收节点的IP组播技术研究

本文分析和研究了当接收节点处在移动环境中时进行IP组播的各种方案,以移动特有的问题为背景,着重讨论了如何综合考虑在组播应用中支持移动接收节点;并对支持组播接收节点移动的各种方案进行了归纳和总结。     

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.     

基于卫星网络的移动可靠组播技术

本文首先介绍了基于卫星网络的可靠组播的优势,然后详细讨论了移动可靠组播及卫星网络可靠组播所面临的新的问题,最后提出了卫星网络中移动可靠组播的解决方案。     

IPv6组播技术的研究

文章在简介IPv6和组播技术的基础上,详细介绍了IPv6下的组播新特性,指出目前IPv6组播技术的几个研究方向,最后介绍了有关IPv6组播技术的研究成果。     

移动因特网及移动IP中的组播技术

移动因特网是因特网和移动通信网未来发展的一个重要方向。本文从因特网协议的层次出发,分析了移动因特网的无线物理和数据链路层、移动IP层等的特点,分析了几种移动IP支特组播的机制。比较了它们与有线因特网层次之间的区别。     

一种基于MobiCast的移动IP组播方案

本文提出一种改进的MobiCast方案来实现移动IP组播通信,主要解决MobiCast方案中进行区域间切换时组播数据包丢失问题。与MobiCast方案相比,在区域外地代理(DomainForeignAgent,DFA)处引入一种缓存的机制。当移动节点发生区域间切换时,移动节点的旧区域外地代理采用隧道技术,将移动节点的信息和缓存的组播数据包发送给移动节点的新区域外地代理处,减少移动节点进行区域间切换时丢失的组播数据包。     

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。     

卫星广域可靠组播技术探讨

针对卫星环境持点简要讨论了卫星广域组播网络结构，分析了卫星可靠组播技术和未来应用需求可能面临的技术挑战。     

基于移动预测的快速分层移动组播体系结构

 由于移动节点的位置是不断变化的,移动IPv6协议给出了支持移动节点的远程加入和双向隧道两种组播方法,但这两种方法都有各自的缺点.本文提出基于移动预测的快速分层移动组播体系结构(mobility prediction based fast and hierarchical mobile multicast architecture,简称MP-FHMM),通过移动预测,在切换前为移动节点配置好切换信息,并且在切换时使用基于FMIPv6改进的快速组播切换方法,有效减少了切换延迟以及由此引发的组播数据分组丢失.另外,由于采用层次型结构的移动组播管理,屏蔽了节点在子网内的移动,减少了因节点移动而重构组播树的频率.     

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.     

基于IPv4的移动IP技术

本旨在介绍移动IP提供的隧道传送机制,即一种“向离开本地网的移动主机路由IP包”的方案,其中主要介绍了机制本身和隧道传送实现的相关技术。     

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.     

Reliable Multicast in Multi-Access Wireless LANs

Multicast is an efficient paradigm for transmitting data from a sender to a group of receivers. In this paper, we focus on multicast in single channel multi-access wireless local area networks (LANs) comprising several small cells. In such a system, a receiver cannot correctly receive a packet if two or more packets are sent to it at the same time, because the packets collide. Therefore, one has to ensure that only one node sends at a time. We look at two important issues. First, we consider the problem of the sender acquiring the multi-access channel for multicast transmission. Second, for reliable multicast in each cell of the wireless LAN, we examine ARQ-based approaches. The second issue is important because the wireless link error rates can be very high.We present a new approach to overcome the problem of feedback collision in single channel multi-access wireless LANs, both for the purpose of acquiring the channel and for reliability. Our approach involves the election of one of the multicast group members (receivers) as a leader or representative for the purpose of sending feedback to the sender. For reliable multicast, on erroneous reception of a packet, the leader does not send an acknowledgment, prompting a retransmission. On erroneous reception of the packet at receivers other than the leader, our protocol allows negative acknowledgments from these receivers to collide with the acknowledgment from the leader, thus destroying the acknowledgment and prompting the sender to retransmit the packet.Using analytical models, we demonstrate that the leader-based protocol exhibits higher throughput in comparison to two other protocols which use traditional delayed feedback-based probabilistic methods. Last, we present a simple scheme for leader election.