【作者】 廖小飞；

【导师】 李津生；

【作者基本信息】 中国科学技术大学 ， 通信与信息系统， 2006， 博士

【摘要】 随着网络的不断发展，用户对网络的需求不断发生变化，要求传输的信息种类越来越多，要求提供的服务质量也越来越高。传统网络的弊端日益突出，甚至限制了网络的进一步发展。主动网络是近年来针对传统网络的弊端和不足提出的一种新型的网络，作为一种新型的网络体系结构，它允许用户或第三方软件开发商对网络进行客户化编程。这种新型的网络体系结构把更多的计算处理任务放到廉价的网络节点中，可实现网络性能优化，加速新技术、新协议标准的开发和应用，具有广阔的前景。它对Internet遗留的问题能提供有效的解决方法，被称为21世纪的网络。主动网络的主要特征是网络中间节点可动态编程，因此网络的行为、性能可以随用户的编程而动态地变化，适应不同应用的需要，呈现柔性的特点。 本论文的工作得到国家自然科学基金(No．90104011，下一代网络体系结构、协议模型与机制)的支持，对主动网络的原理与特点、主动网络体系结构、主动网络平台与仿真、主动网络协议模型进行了详细的分析和深入的研究。在研究中，我们重点研究如何将主动网络与现有的传统网络进行融合，这样即兼容延伸了传统网络，又具有主动网络的灵活性，不但使得两种本质不同的网络相互融合，而且还使得在传统网络中更快、更好地实现该技术，或者利用该技术的新特性。这对于网络的演化发展具有非常重要的借鉴意义。 论文主要研究主动网络在移动IPv6、无线网络、移动代理环境中的协议与机制，通过仿真和分析等手段，创新性的进行了如下研究： 近年来，随着高性能便携式计算机的使用和无线局域网技术的进步，移动IP技术已经成为移动通信发展的必然趋势，然而互联网工程任务组IETF提出的移动IPv6协议在移动切换过程中具有许多缺点，例如切换延时过大，等待时间太长，旧接入路由器的报文缓冲区容易溢出等。针对IETF制定的移动IPv6协议在切换过程中所存在的问题，提出一种基于主动网络技术的方案来解决这些问题，改善移动IPv6的性能。通过网络仿真，证明这种方案具有更多的优点和更高的性能。 由于互联网用户呈现出爆炸式增长，无线通信网络迅速发展，以及各种便携式终端大量使用，使得人们在无线环境下对互联网业务的需求不断增长。无线通信与互联网相结合成为未来无线通信(包括移动通信)发展的大趋势。然而，由于无线网络的特性使得这种类型的网络存在许多问题，例如TCP在这种混合网络中性能会下降。针对无线网络的特有缺点，提出了一种新的架构AWA，以解决无线链路的问题；并以一种执行环境为例，来解决无线链路的高比特误码率(Bit-error Rate)特性和存在的移动切换所导致的TCP在无线环境中性能下降问题，该方案可以根据无线链路和客户节点的特性，自动选择最适合的TCP，改善无线链路上的TCP性能。通过网络仿真，证明这种架构具有更高的性能和更多的优点。 由于移动代理技术已经很成熟，具有广泛的应用，但是移动代理实现在应用层，着重于灵活性和更多的功能；在性能和管理方面存在较大的问题，尤其对于所有的业务如何构建一个通用的平台比较困难，需要解决这方面的问题。针对移动代理与主动网络的结合问题，提出了一个通用的架构ANMA，解决了当前各种不同实现方案的兼容性问题和互操作性问题。并在此架构上给出了一个原型应用——主动搜索引擎。这种架构对于业务具有通用性，更适合于下一代网络，而且更适合应用在主动网络环境、移动代理环境以及传统网络环境中。并通过引入应用层组播模型，将应用层组播和移动代理相结合，对搜索引擎模型进行改进，提更多还原

【Abstract】 With the development of network, users’ demand on network change persistently. The kinds of information transmitted are more and more and the quality of services (QoS) provided is more and more. Malpractices of the traditional network stand out increasingly, and have limited the further developing of network. The active network is a new type of networks proposed recently for overcoming drawbacks of traditional IP network. As a new approach to network architecture which allows users or the third part software providers to perform customized programming. The new type architecture of networks can optimize the performance of networks, accelerating the development and application of new technologies and protocols by distributing lots of computing tasks into the cheap nodes of networks. And has promising direction. It can provide efficient solutions to the problems from Internet. Then it is called the networks of 21st century. It is mainly characterized by the programmability of intermediate network nodes such as routers. The behavior and performance of the network can vary dynamically according to user programs to adapt the needs of different applications, presenting a flexible nature.The work of this dissertation, which is supported by the National Science Foundation of China (No. 90104011, Research on the Architecture, Protocol Model, and Mechanisms of the Next Generation Network), analyses and researches the principle and characteristics of active networks, active network architectures, active network platform and simulation, and model protocol of active network. In my research, we focus on how to amalgamate active network and traditional network, so as to extend the traditional network and have flexibility of active network. It is not only combined the two kinds of different essential network, but also realize active network technology in the traditional network rapidly and effectively, or using new characteristics of this active network technology. It will use for reference in the design and evolvement of network.By analyzing the protocols and mechanisms of active network in the environment of mobile ipv6, wireless network and mobile agent, and with the help of network simulation and theory analysis, some creative ideas and results are obtained in this dissertation as following:With the use of high performance portable computer and advancement of wireless local area network, mobile IP is the trend of mobile communication consequentially. However mobile IPv6 protocols proposed by IETF have some shortcomings in handoff process, such as great handoff delay, long latency time, packet buffer overflow in the old access router and so on. We put forward an approach based on active network technology to solve the problems and enhance mobile IPv6. Network simulation proves that this approach has more merits and better performance.With the advance in computer communication technology, development of hardware and software, popularization of portable computer, increasing need for access to Internet and Intranet, wireless communication has a new opportunity to develop rapidly and integrate into the traditional network. Nowadays the interest in the use of wired-and-wireless-integrated networks has spawned. However there are many problems in this type network due to the wireless network’s characteristics. We propose an architecture named AWA (Active Wireless Architecture) based on active network technology to solve the problems caused in wireless network, especially enhance更多还原