摘要
随着现代通信技术和网络的高速发展，传统网络机制已经不能够满足新型网络应用的需求。传统网络的交换设备只能进行简单的报头处理和被动的数据转发，路由协议及交换方式相对固定，无法根据应用的特殊需求而加以定制，也无法及时更新以适应层出不穷的新应用的需要。用户无法参与报文和数据的转发过程，对报文穿越网络的路径和此路径沿途的服务质量更是无法加以控制。因此，研究人员提出主动网的概念，以此来解决现有网络中存在的这些固有的问题。主动网中的节点被称作主动节点，主动网中的数据报文被称作主动包；主动节点不仅进行主动包的存储—转发，更提供了主动包中用户代码的执行环境。
论文以江苏省自然科学基金项目“高性能网络路由器交换系统的算法与协议”为背景，主要研究了主动网对具有QoS保障的主动路由机制的支持，以及如何利用主动网来实现端用户可定制的主动路由。通过比较主动网与传统网络在路由选择上的异同，本文探讨了在主动网环境下实现主动路由的可行性和实施方案；通过对主动网工具包ANTS的扩展，在其框架中增加主动路由定制模块和用户调用的统一接口，使之支持具有QoS选路特性的主动路由；通过在该环境(QCAR)中主动路由应用的实现和部署，验证了新框架的合理性和可行性。
论文的研究工作和主要成果包括以下几个方面：
(1) 研究主动网与传统网络的在路由机制上的异同，并指出利用主动网来实现可定制路由的可行性和优势，并分析可能的实施方案。
(2) 研究分析多种主动网系统的设计，通过对安全性、性能、可移植性、二次开发支持等多个指标的综合考察，确定采用ANTS为论文中主动路由系统开发的基础。
(3) 研究传统网络的服务质量特征参数，选择合适的度量参数以反映网络的主要特征和网络流量的QoS需求，并将QoS选路问题抽象成一个多约束条件下的选路问题。
(4) 研究分析主动网工具集ANTS的基本工作机制，针对其在主动路由支持上的不足提出改进方案——QCAR系统。
(5) 通过将QoS参数扩充进系统状态数据库，增加主动路由模块，并向用户提供支持QoS需求的统一接口，完成了面向单播应用、具有QoS主动路由功能的QCAR系统，该系统支持多种QoS定制模式。
(6) 在完成QCAR系统的基础上，实现并部署了端用户可定制的QoS主动路由应用程序TraceRtApplication。
(7) 在TraceRtApplication程序的基础上，通过对多种网络拓扑环境和多种QoS需求数据流的运行检测，完成了QCAR系统的功能测试，证明了它对QoS主动路由支持的正确性和可行性。
(8) 完成了AntsManager软件，实现对QCAR系统的图形化界面封装，改变了以往ANTS纯文本命令行的操作方式。应用AntsManager软件，用户可以设置或者修改实验的
拓扑结构、各链路参数的取值，以及报文传输过程中的QoS需求；系统将根据这些设置自动生成配置文件和脚本文件、启动相应的主动路由应用程序，并以动画形式将主动包的选路结果直观地呈现给用户。
With the rapid development of modern communication technology and networks, traditional mechanisms can no more satisfy the requirement of new types of network applications.Traditional switching equipments can only accomplish simple processing of packet headers and passive transmission of data. The routing protocols and switching modes cannot be customized according to extra requirements of applications, or renovate in time to adapt the numerous emerging applications.So customers cannot take part in the transmission processes of packets and data, or control the path that packets pass through the network to assure the Quality of Service along the way.Thus, the concept of active network was promoted to solve the inherent problems of existing networks. The nodes in active networks are called active nodes, while the packets in active networks are called active packets. Active nodes not only are in charge of storing-forwarding of active packets, but also provide the user code contained in active packets with executing environments.
This thesis was supported by the JiangSu Natural Science Foundation project "Research on the algorithms and protocols in high-performance routing and switching network systems". The research work of this thesis focuses on the active network's support to active routing mechanisms with QoS guarantee, and on how to use active network to realize the QoS-customized active routing.By comparing the similarities and differences of routing mechanisms in active network and in traditional network, this thesis discussed the feasibility and implementing scheme of active routing in active network; extended the active network toolkits-ANTS, including adds an active routing customizing module and unified interfaces which can be called by users in its framework, to make it support active QoS routing; realized and deployed an active routing application in QCAR to validate the rationality and feasibility of this new framework.
The main research work and achievements includes the following parts:
(1) Compared the similarities and differences of routing mechanisms in active network and in traditional network; pointed out the feasibility and advantages of using the active network to realize the customized routing; analyzed possible implementing scheme.
(2) Studied and analyzed the design of several main active network systems; comprehensively surveyed their performance parameters including security、 performance、 portability and SDK support, and ultimately choosed ANTS as the foundation for the development of our active routing system.
(3) Studied the characteristic QoS parameters of traditional network; choosed a proper set of
them to reflect the main characters of network and the QoS requirements of network flows, and abstracted the QoS routing problem to a multi-restricted routing problem.
(4) Studied and analyzed the basic working mechanism of active network toolkit-ANTS; pointed out its deficiency in supporting the active routing, and proposed a scheme to improve on the ANTS framework—QCAR.
(5) By extending the database of system statements with QoS parameters, adding an active routing module, and offering the users unified interfaces that support the transfer of QoS requirements, completed the QCAR system which supports different QoS customizing patterns and has the ability to complete the QoS active routing of unicast application.
(6) Based on the QCAR system, realized and deployed the user-customized QoS active routing application program—TraceRtApplication.
(7) Based on the TraceRtApplication program, through testing the running time of data flows carrying their respective QoS requirements in various network environments of different topologies, completed the function tests of QCAR system, proved the validity and feasibility that QCAR can support the QoS active routing.
(8) Developed a new software—AntsManager, which substitutes the graphic interface of QCAR
system for primary (text only) command line operation mode. Users can use AntsManager to set or modify the topology of each experiment, link state values and QoS requirements of packets transmission process. System can automatically create configuration files according to these settings, startup corresponding active routing application program and directly present the routing result of active packets to users in dynamic style.
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