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.     

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。     

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。     

基于Mtrace的Ipv6组播监听的实现

针对日益增多的高带宽需求的多媒体应用，下一代互联网协议——IPv6提供了增强的组播技术。在IPv4向IPv6推进的过程中，一些IPv6环境下组播相关的问题亟待解决，其中之一就是提供用于组播管理的工具。介绍了IPv6组播相关技术，并基于Mtrace在开源的IPv6协议栈——KAME上实现了一个IPv6组播路由查找工具。     

IPv6组播路由协议仿真研究

分析了PIMIPv6组播路由协议的原理．在NS2网络模拟环境下设计了组播网络仿真模型，编写了实现PIM组播路由协议的代码。成功模拟了协议运行过程。在此基础上。对比分析了不同PIM组播路由协议的性能特点，并指出了其应用特性。     

IP网组播的实现机制（下）

广域网上的组播实现有多种技术方式，但是最常用的实现方式是采用PIM—SM组播路由协议。PIM—SM协议与单播路由协议无关，并可同时支持基于源的组播树和共享树两种组播方式，特别是它是实现跨AS域组播的基础。因此，当前多数网络是以PIM—SM作为其组播路由协议。下面，将针对实例详细介绍PIM—SM的组播实现方式。     

IP组播技术研究与实现

主要介绍了IP组播技术、IP组播协议的分类及域内组播路由协议比较;详细地给出了综合业务交换机上IP组播软件的实现框架,并对PIM-SM组播路由模块、IGMP协议模块和组播数据转发模块的设计进行了简要的说明。IP组播技术的应用将不断得到重视和扩大。     

IP多播技术及其应用

本简单地阐述了IP网络上多播（Multicast)技术的概念、特点与原理，介绍了在公用IP网络中部署PIM-SM组播业务的实现方法、其结构体系和路由组织，分析所涉及的相关协议，并介绍了基于IP组播技术的应用解决方案和近年来组播技术的发展。     

基于NS2的"计算机网络"课程辅助教学探索

本文以NS2网络仿真软件为基础,构建了＂计算机网络＂课程辅助教学的软件平台,深入研究了计算机网络课程涉及的IP网络路由协议,包括单播路由中的会期路由、动态路由和距离向量组播路由协议DVMRP及PIM。我们使用NS2包含的网络仿真元素,采用OTCL语言编写脚本,通过NAM动画演示会期路由、动态路由和DVMRP、PIM协议的动态运行过程,可以增强学生对IP网络路由协议中概念的掌握和理解,也能增加他们对＂计算机网络＂课程的学习兴趣。     

基于IPv6的MLD协议的研究与实现

IP组播是一种优化使用带宽的路由技术,它允许IP数据流从一个源或者多个源发送到多个目的地,使用组播技术可以有效地减少网络流量.它可以利用最少的网络带宽将组播源的数据报传送给多个接收者,并且不会给接收者和发送者带来任何额外的负担.随着多媒体业务的日益增长,对带宽的需求越来越大,IP组播技术有了广阔的应用空间,在多媒体服务、软件分发、网络游戏、流媒体等诸多领域都有着广阔的前景.良好的组播业务的实施需要有完善的管理机制,MLD协议就是保障IPv6下组播技术有效进行的管理控制协议.本文介绍了给出了Linux操作系统下组播组管理协议的具体实现,为实现IP组播提供了有利的支持.     

Arranging multicast forwarding table in class sequence in ternary-cam for line-speed lookup

PIM-SM (Protocol Independent Multicast-Sparse Mode) is a main multicast routing protocol in the IPv6 (Internet Protocol version 6). It can use either a shared tree or a shortest path tree to deliver data packets, consequently the multicast IP lookup engine requires, in some cases, two searches to get a correct lookup result according to its multicast forwarding rule, and it may result in a new requirement of doubling the lookup speed of the lookup engine. The ordinary method to satisfy this requirement in TCAM (Ternary Content Addressable Memory) based lookup engines is to exploit parallelism among multiple TCAMs. However, traditional parallel methods always induce more resources and higher design difficulty. We propose in this paper a novel approach to solve this problem. By arranging multicast forwarding table in class sequence in TCAM and making full use of the intrinsic characteristic of the TCAM, our approach can get the right lookup result with just one search and a single TCAM, while keeping the hardware of lookup engine unchanged. Experimental results have shown that the approach make it possible to satisfy forwarding IPv6 multicast packets at the full link rate of 20 Gb/s with just one TCAM with the current TCAM chip.     

Multicast support for mobile hosts using Mobile IP: Design issues and proposed architecture

In this paper, we consider the problem of providing multicast to mobile hosts using Mobile IP for network routing support. Providing multicast in an internetwork with mobile hosts is made difficult because many multicast protocols are inefficient when faced with frequent membership or location changes. This basic difficulty can be handled in a number of ways, but three main problems emerge with most solutions. The tunnel convergence problem, the duplication problem, and the scoping problem are identified in this paper and a set of solutions are proposed. The paper describes an architecture to support IP multicast for mobile hosts using Mobile IP. The basic unicast routing capability of Mobile IP is used to serve as the foundation for the design of a multicast service facility for mobile hosts. We believe that our scheme is transparent to higher layers, simple, flexible, robust, scalable, and, to the extent possible, independent of the underlying multicast routing facility. For example, our scheme could interoperate with DVMRP, MOSPF, CBT, or PIM in the current Internet. Where differences exist between the current version of IP (IPv4) and the next generation protocol (IPv6), these differences and any further optimizations are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Layer 3 VPN Services over IPv6 Backbone Networks: Requirements, Technology, and Standardization Efforts

Layer 3 virtual private networks (L3VFN) enable organizations to connect geographically dispersed sites to one another across the packet switched network of a service provider. The most popular form of L3VPN is based on BGP/MPLS (border gateway protocol/multiprotocol label switching) technology in which the service provider offers a network-based IP VPN routing and forwarding service to its customers across its own IPv4-based MPLS backbone network. With the deployment of IPv6-based backbone networks underway, there is an emerging requirement to support these same L3VPN services across a native IPv6 backbone network. This introduces a requirement to provide routing and tunneling of IPv6 VPN (and IPv4 VPN) packets across an IPv6 backbone network. Softwires is an Internet Engineering Task Force (IETF) Working Group chartered to address the requirement of providing a generalized, network-based, multi-address family, IP routing and tunneling capability across native IP backbone networks pursuant to IPv6 transitions. Elements of the softwires work can form the basis of an L3VPN over IPv6 solution. After providing a brief overview of how L3VPN works in various topologies, this article presents the requirements for L3VPN services over an IPv6 backbone network and discusses a possible solution set that builds over the softwire technology and related IETF standards. Finally, we outline future directions and how the softwire technology can support new services and improved scalability     

“IPv6+”技术标准体系

“IPv6+”的愿景是通过对IPv6技术的扩展和增强释放IPv6的技术潜力,满足5G和云时代对大规模、高可靠、新业务和智能化IP网络的需求。“IPv6+”的技术内涵包括以SRv6网络编程、网络切片（VPN+）、随流检测（iFIT）、新兴多播（BIERv6）、业务链（SFC）、确定性网络（DetNet）和感知应用网络（APN）等为代表的一系列协议和技术创新,目前正在各标准组织中分阶段进行标准的研究与制定。标准化是“IPv6+”技术创新的重要工作,全面地定义了“IPv6+”技术标准体系,包括与“IPv6+”相关的标准组织、“IPv6+”标准全景图、“IPv6+”标准创新3个阶段以及每个阶段的关键技术创新和标准布局。     

基于IPv4/IPv6协议转换技术的IDC过渡方案

由于IPv4地址的短缺,未来网络将向下一代IPv6网络过渡,并且由于IPv4与IPv6的差异,使得这两个网络之间无法互相通信。为在过渡期间,用户能够同时享受IPv4与IPv6两个网络的服务,运营商必须使用IPv4/IPv6网络过渡技术,以达到平滑过渡的目的。文章讨论在教育网中如何通过IPv4/IPv6协议转换技术使IDC机房从IPv4网络平滑过渡到IPv6网络的一个通信场景和解决方案。     

利用上下文转移实现移动IPv6上的IMS无缝切换

Mobility support for the next generation IPv6 networks has been one of the recent research issues due to the growing demand for wireless services over internet. In the other hand, 3GPP has introduced IP Multimedia Subsystem as the next generation IP based infrastructure for wireless and wired multimedia services. In this paper we present two context transfer mechanisms based on predictive and reactive schemes, to support seamless handover in IMS over Mobile IPv6. Those schemes reduce handover latency by transferring appropriate session ＇information between the old and the new access networks. Moreover, we present two methods for QoS parameters negotiations to preserve service quality along the mobile user movement path. The performances of the proposed mechanisms are evaluated by simulations.     

Domain Constrained Multicast: A New Approach for IP Multicast Routing

One of major reasons why IP multicast has not been well deployed is the complexity of IP multicast routing. Since existing IP multicast routing protocols have been designed independently of IP unicast routing protocols, a router must maintain routing tables for both IP mutlicast and unicast routing. This is, in particular, a big burden for an inter-domain router. In addition, by using existing IP multicast routing protocols, we cannot realize an application that a sending host outside the designated domain sends IP multicast packets only towards the designated domain. To resolve above issues, we propose a new architecture for IP multicast, which is called Domain Constrained Multicast (DCM). In this architecture, IP multicast packets are forwarded to a border router of the designated domain using IP unicast routing. And then, IP multicast packets are delivered inside the designated domain using IP multicast. We propose an address format when realizing the DCM architecture using IPv6. We describe the extension of the DCM architecture for applying it to inter-domain IP multicast routing. Finally, we have compared the DCM architecture for inter-domain routing, with existing inter-domain IP multicast routing protocols such as MSDP and BGMP.     

组建IPv6核心网络的方案探讨

随着基于IPv6协议的下一代互联网(NGI)在中国逐渐开始部署,如何组建电信级IPv6核心网成为运营商关注的重要问题.本文首先提出了IP核心网络演进的原则,然后分别介绍和分析了IPv6网络的多种互通与过渡技术,并列举了国外运营商IPv6核心网络的演进方案,最后给出了总体实施建议.     

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。