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。     

IPv6组播技术综述

综述了IPv6组播的新特性及相关协议，指出目前组播技术的研究热点，介绍了当前国内外IPv6组播标准研究、协议实现及试验网的情况。     

IPTV中的IPv6 PIM-SSM组播通信技术的研究

本文通过分析IPv6PIM-SSM（源特定组播）的工作原理,提出了源特定组播的实现方案,有利于在IPv6的环境下解决IPTV的组播通信问题。     

IPv4-IPv6组播过渡技术

要使IPv4主机与IPv6主机进行组播通信，必须做协议转换工作。采用多播转换网关（MTG）技术方案能较好地实现IPv4网和IPv6网之间的组播互通。方法是将MTG部署在lPv4和IPv6网络的边界，将IPv4网络和IPv6网络视为地位对等的两个异构网络。IPv6主机可以加入组播源位于IPv4网络的组播组，IPv4主机也可以加入组播源位于IPv6网络的组播组。在IPv4中，MTG作为IPv6的代理，参与IPv4的组播；同样，MTG在IPv6中则作为IPv4的代理。在MTG系统内部，两个代理之间进行协议转换。     

IPv6组播通信的研究与实现

随着Internet的飞速发展,IPv6必然会取代IPv4。由于组播技术的优越性,IETF在制订IPv6协议时保留了组播,而取消了广播。IPv6组播技术可避免网络资源浪费,减小网络拥塞和广播风暴等问题,能有效利用带宽,提高数据传送效率,尤其适合视频流等大数据量的传输。介绍了IPv6组播技术的基本原理,具体说明了IPv6组播在Linux下的编程方法和通信过程,相信对IPv6组播技术的应用有较大的帮助。     

基于IPV6的组播路由协议PIM-SM的研究及实现

文章首先分析了研究IPv6组播技术的重要意义.然后详细分析了组播路由协议PIM-SM,并且在实验室生成IPv6环境下,对PIM-SM协议中的BSR选举、RP竞争、HelIo消息发布和数据流树切换等进行了测试,测试结果表明该协议工作正常,以其为基础实现的组播系统是正确的,符合RFC相关文档说明.     

IPv6组播技术的研究和实现

文章介绍IP组播的基本原理,在分析IPv6组播协议工作原理的基础上,提出基于IPv6的PIM-SM协议的实现方案。     

IPv6网络中组播路由--PIM技术研究

随着网络宽带用户和下一代互联网的发展,多媒体业务相关服务如网络电视(IPTV)需求的日益增长刺激了IP组播技术的普及和发展,使其成为新一代网络中不可缺少的关键技术.与单播应用相比,采用IP组播技术分发信息常常能从本质上减少整个网络对带宽的需求.文章从IPv6网络的各种组播技术入手,详细介绍了当前在实际网络中获得广泛应用的基于协议无关组播(PIM)的组播路由技术 ,重点介绍了域内组播路由中使用最广泛的PIM稀疏模式(PIM-SM).对整个PIM-SM组播路由协议在IPv6网络中的运行过程进行了论述,最后介绍了其在未来IPTV等网络应用中的前景.     

MLD协议与PIM-SM协议实现IPv6组播

文章主要介绍IPv6组播的原理机制，当前用于实现IPv6组播的两个基本协议MLD协议与PIM—SM协议，以及MLD协议与PIM-SM协议之间的互操作。同时还详细描述了组播共享树和最短路径树的建立过程。     

基于IPv6的QoS控制组播路由机制

设计并实现了一种基于IPv6的QoS(quality of service)控制组播路由机制.基于启发式单播路由协议,修改了PIM-SSM协议与MLD协议,实现了IPv6下启发式源特定组播.为提供QoS控制,扩展了RSVP协议,设计了分层组播流量控制机制,基于博弈分析确定为用户预留的带宽量,优化网络提供方与用户方效用.开发了该机制的原型系统并进行了大量试验,结果表明该机制具有良好的性能,能够提供IPv6下的QoS控制组播路由.     

Multicast delivery using explicit multicast over IPv6 networks

This article presents an alternative scheme, called Xcast6+, which is an extension of explicit multicast (Xcast) for an efficient delivery of multicast datagrams over IPv6 networks. The mechanism incorporates MLDv2 and a new control plane into existing Xcast6 (Xcast for IPv6) and not only does it provide the transparency of traditional multicast schemes to sources and recipients, but it also enhances the routing efficiency in networks. Since intermediate routers do not have to maintain any multicast states, it results in a more efficient and scalable mechanism to deliver traditional multicast datagrams. Furthermore, the seamless integration of Xcast6+ in Mobile IPv6 can support multicast efficiently for mobile nodes over IPv6 networks by avoiding tunnel avalanches and tunnel convergence. Our simulation results show distinct performance improvements of our approach. This approach can reduce network resources in many "medium size groups" multicast, particularly as the number of recipients in a subnet increases (i.e., "subnet-dense groups").     

IPv6的地址结构特点与管理机制分析

本文主要介绍了有关IPv6互联网的网络地址结构及其管理机制。与现行的IPv4地址相比,IPv6在地址的长度、分类方法、表示方法和类型等方面均不同相同。它可有效地解决IP地址枯竭与路由效率低下的问题,同时具有地址聚类性、多播性、任播性和接口多址性等特点;而在IPv6地址管理方面则采用层次化路由选择策略,支持QoS路由协议,将地址解析通过领导发现协议来实现,新增了无态地址的自动配置,使得网络地址的重新编号变得更加简单快速。最后通过模拟仿真的方法,进一步分析说明了IPv6网络的性能。     

嵌入式IPv6网络视频终端

介绍了以Intel XScale处理器PXA270为核心的嵌入式系统平台,分析了IPv6组播与流媒体协议原理,移植了对IPv6有良好支持的Linux操作系统及Qtopia嵌入式图形系统.在此基础上,针对上述嵌入式系统移植和优化开放源代码的优秀媒体播放器MPlayer,实现了支持IPv6组播与流媒体传输的嵌入式IPv6网络视频终端.随后对该视频终端的媒体播放性能进行了测试与分析,并搭建了移动IPv6试验床,通过与IPv6网络流媒体服务器联机验证了视频终端功能.     

IPv6组播技术在体育院校远程教育中的应用

通过对IPv6组播技术在地址、信息传输等方面的分析,结合网络与体育院校发展的需要,构建了体育院校远程教育基本的组播应用系统,其目的是为充分发挥和利用IPv6组播技术的优势,推动我国体育教育和远程教育的发展与进步。     

The Performance Analysis of the Multicast Extension Support for Proxy MIPv6

Mobile multicast is based on the traditional multicast protocols and the mobility support protocols to provide the multicast services for the mobile subscribers. Several mobile multicast methods were proposed in the past few years, but most of them are based on Mobile IPv6 and its variants which require the mobile node to support the mobility function. Recently, Proxy Mobile IPv6 (PMIPv6) was proposed to provide the mobility support for the mobile node with or without mobility function, and the previous studies have shown that PMIPv6 can improve the performance in term of the handover performance and protocol cost. However, PMIPv6 mainly concerns on the mobility support for unicast routing and little considers the multicast routing. In this paper, we propose two multicast methods called the MAG (Mobile Access Gateway)-based method and LMA (Local Mobility Anchor)-based method based on the different multicast delivery transmission path to extend PMIPv6, and analyze their performance under the different scenarios. The analytical results show that the LMA-based method is suitable for the higher speed, bigger domain size, and larger network topology scenarios, whereas the MAG-based method is suitable for the lower speed, smaller domain size and smaller network topology scenarios.     

Reliable Key Management and Data Delivery Method in Multicast Over Wireless IPv6 Networks

Multicast is an efficient way to reduce the required bandwidth of transmitting data simultaneously to a group of users in wireless IPv6 networks. Nevertheless, multicast suffers from two main drawbacks which can be looked from two perspectives, namely security and QoS. With regard to security, the main challenge is to provide security protection to multicast data, which can be achieved by using a secure key management process. Considering a highly dense environment where connection of users to the network is changing frequently due to join or leave operations, key updating approach may burden a network devices with a huge amount of complex encryption/decryption processes. From the QoS perspective, multicast transmission over WLAN offers a tradeoff between the transmission rate and the coverage. The transmission rate of multicast is confined by the user with the lowest data rate in the group which is called fixed base rate problem. To address the above mentioned problems, we propose and implement a lightweight key management and data delivery scheme for multicast over wireless IPv6 networks. The proposed solution is envisaged to reduce the complexity of key updating, while at the same time is able to address the fixed base rate problem. The performance evaluation (by means of analytical and test-bed implementation) of the proposed key management method indicates its efficiency in reducing communication, computation, and storage costs, while maintaining both forward and backward securities. Moreover, the proposed data delivery method is able to improve the throughput and QoS, with low packet loss and transmission delay.     

6LowPan邻居发现优化策略

IETF 6LowPan工作小组定义了基于低功耗个域网的IPv6协议。邻居发现是一种专用于IPv6的新协议,由于6LowPan网络应用的特点,邻居发现协议必须优化。为了更好地降低功耗,提出了限制多播路由请求和路由公告,避免重复地址检测、多播邻居请求和邻居不可达检测信息等一系列6LowPan邻居发现优化策略。