IPv6中选播问题的研究

【作者】 柳溶；

【导师】 杨路明；

【作者基本信息】 中南大学 ， 计算机应用技术， 2002， 硕士

【摘要】 随着网络技术的飞速发展，因特网呈现出了许多新的趋势，人们对因特网也提出了新的要求。一方面，在用户呈指数级增加的情况下，在网络中如何保证并提高服务质量(QoS，Quality of Service)显得尤为重要；另一方面，在网络中出现了越来越多需要移动的用户，这些用户迫切希望可以随时随地地接入网络，共享网络资源。IPv6是新一代路由协议，将最终取代IPv4。 选播(anycast)是IPv6中特有的路由方式，是一个源节点与一组节点中任意一个进行的数据传输。这一组节点拥有一个相同的选播地址，任意节点通常是这组节点中距离源节点最近的节点：选播可以改善服务质量。因特网工程任务组IETF提出的MIP(移动IP，Mobile IP)是一种在全球因特网上提供移动功能的解决方案，它使节点在切换子网时仍然可以保持正在进行的通信，使移动节点离开家乡子网时仍能透明的路由数据包。 本文首先讨论了IPv6以及MIPv6的相关问题，然后着重分析IPv6新特点、寻址方式与MIPv6的实现。在此基础之上提出新的内容，用来实现对选播服务的优化。本文提出了一个新的协议模型，通过TCP连接总数确定选播地址对应的最佳服务器，有效地解决由当前选播路由协议确定的最近服务器产生网络拥塞时如何改善路由策略问题，从而实现负载平衡并提高网络的传输性能。基于MIPv6，本文还提出了一个简洁的报文结构模型，该模型通过对现有IPv6中ICMP路由器发现报文的改进，实现了对网络性能的改善，同时对目前正在使用的协议和路由算法影响不大。在该模型中，ICMP路由器发现报文的内部结构在原有的基础上进行了一定的改进，使得移动节点到达一个新的子网时，获得转交地址和申请选播服务的实现不必经过以往的两个报文发送——接收过程，而只需一个过程。模型对网络性能的改善体现在：缩短转交地址获得和选播服务确定的时间，简化ICMP报文的类型，节约网络带宽资源。更多还原

【Abstract】 In recent years, with the rapid development of the network technology , many new trends appear and new commands are put forword .It is very important that how to ensure and improve the QoS(quality of service). With the rapid development of Internet, more and more users who need mobile services appear. IPv6 , the new generation routing protocols, will finally take place IPv4.To advance to a higher QoS, the way of mirror servers is always adopted hi the Internet. Anycast service can improve the distribution of net payload and simplify some net applications. As originally introduced in RFC 1546, anycast is a way to reach the mirror that is the closest. However, the closest mirror server is not always the best mirror server. Load balancing is a mode of traffic distribution via using the redundant links provided. Anycast is this type of network service that delivers a datagram to any one server out of a group of servers distributed throughout the network. Mobile IPv6 pellucidly supports the nodes to move and maintains current communication when the node switches between the subnets.In this paper, firstly we briefly describe the basic principle of TCP/IP and IPv4, and then Mobile IP. Based on IPv6 anycast routing protocol, a new protocol model is proposed. Via sum of TCP connects, it confirmes the best server toward some anycast address, and effectively solves the problem that how to improve the routing policy when the server confirmed through current routing protocols is jammed. It can implement load balancing and promote the transmission performance of the net. Furthermore, hi this paper a concise model of message construction based IPv6 is proposed. This model improves the net performance via improvement on IPv6 ICMP Router Discovery Message, with influence on the current protocol and alogorithm as less as possible. When a node arrives a new subnet, the implement of obtaining care of address and confirming anycast service needs only one message send-receive procedure, not two procedures as before. The advantages of this model is that: shortening the period of obtaining care of address and confirming anycast services, simplifying IPv6 message types, saving net bandwidth resources.更多还原