高性能路由器操作系统HEROS中的高可用性设计

为了保证路由器系统的整体性能和安全性，清华大学设计并实现了用于骨干网络路由器的高性能路由器操作系统HEROS（Highly Efficient Router Operation System）。骨干路由器是Internet的核心，为了保证网络的平稳运行，需要其具有相当高的可用性。本文首先分析了骨干路由器的高可用性要求，设计并实现了一种基于消息传递机的面向协议软件的高可用性系统。该系统具有对上层协议透明，独立于底层传输机制等优点，在采用主节点双机备份的硬件条件下，可以保证系统软件无故障地平稳运行。     

片上网络路由器设计初探

近几年.片上网络路由器的设计研究逐渐成为人们研究的焦点,在片上网络路由器的设计过程中.主要涉及:拓扑结构、路由算法、交换机制及仲裁机制等几方面问题.以下将分别对这几个方面的基本理论进行说明.     

基于扩展服务路由器的主动网络体系结构

结合当前主要的两种主动网络实现策略的优点提出了一种新的基于扩展服务路由器的主动网络体系结构,该体系结构由扩展服务路由器,主动扩展组件服务器和密钥分发中心KDC组成,用户可以使用编程接口编写可扩展组件,为了保证安全性,设计了一种简化的身份认证协议,目前,基于分布式实时操作系统VxWorks的扩展服务路由器原型系统和基于Solaris的主动扩展组件服务器和KDC原型系统已经设计完成。     

基于IPv6的PIM-SMv2协议的设计与实现

在新一代互联网中,支持组播已成为对路由器的基本要求。PIM-SM是一个不依赖于某一特定单播路由协议的组播路由协议,为组播数据转发提供路由信息。本文介绍了高性能：IPv6路由器协议栈软件中基于原始套接字(Raw Socket)通信机制的PIM—SMv2协议的设计与实现,并搭建实验环境对实现的系统进行了测试。实验结果表明,该系统已具备IPv6组播功能。     

一种适用于WIA-PA网络的安全路由机制

路由是WIA-PA网络通信的前提,路由安全是WIA-PA网络通信安全的基础,本文设计了一种集中式和分布式相结合的信任管理机制,提出了一种适用于WIA-PA网络的安全路由机制,能够在保证时延和能耗平衡的基础上有效的抵制选择性转发等内部攻击的入侵。     

基于访问列表控制的Cisco路由器安全策略初探

随着网络技术的快速发展,黑客的入侵手段越来越高明,网络常常受到攻击。路由器作为Intranet和Internet的网间互连设备,位于不可信任网络和可信任网络之间,是保证网络安全的第一关,安全性已成为路由器设计中最关键的技术问题。本文对基于访问列表控制的路由器安全策略进行了探讨,并以最常用的Cisco路由器为例进行了分析。     

通过路由策略实现网络控制

本文探讨了通过路由策略实现网络控制。首先介绍了子网访问控制存在的问题,然后提出了路由工作原理,接着,详细阐述了静态路由实现网络访问的控制,并探讨了如何利用软件路由器来实现局域网内部的流量控制。     

基于NS-3构建网络环境的虚实结合技术的研究

研究了网络环境的构建。针对构建网络环境的传统试验床技术代价高,网络仿真真实性差的缺点,提出了一种基于网络仿真器NS-3的新的网络环境构建技术。为了实现物理网络和仿真网络的对接(简称虚实对接以及物理网络和仿真网络的路由策略,该技术采用基于虚拟网卡桥接的虚实对接设计。为实现虚实之间的数据通信,虚拟网卡桥接采用基于轮询机制的监测算法(PMA),路由策略采用基于广度优先搜索的路由改进算法(BFSIA)。利用ping命令和IRC僵尸网络对构建网络进行了测试,测试结果表明用这项技术可进行真实的数据包转发。通过设定不同规模的网络拓扑测试了BFSIA计算路由所消耗的时间,并和NS-3全局路由算法进行了比较,证明了BFSIA的优越性。     

分组传送网及城域网IP化进程的思索

分组传送网(PTN)是城域网IP化进程的重要选择。介绍PTN技术及其标准进展,并对城域承载网络的不同实现技术MSTP、PTN和路由器方案进行对比分析,最后针对城域网IP化进程中存在的问题和技术发展前景进行展望。     

基于MIP的网络移动的实现

主要探讨基于移动IP的网络移动性的实现方法,重点研究移动网络的路由机制,分析在不同情况下路由的实现,并且进一步探讨路由的优化方法和嵌套移动网络的问题。     

Cascaded cuckoo search optimization of router placement in signal attenuation minimization for a wireless sensor network in an indoor environment

Optimization of the energy required during data transmission in a wireless indoor area network can be achieved through intelligent router placements to keep the network active for longer and improve the packet delivery ratio. In this work, a cascaded cuckoo search algorithm (C-CSA) approach is implemented for optimal router placement in a wireless indoor area network based on minimization of signal attenuation during data packet transmission through a novel mathematical formulation. The transmission energy for each packet, signal-to-noise ratio and packet error ratio are studied over 50 independent runs of the algorithm. The results are presented with statistical confidence to prove the efficiency of the algorithm. C-CSA provides superior results for data transmission energy and the packet delivery ratio compared to existing algorithms. Physical placement of wireless nodes in a building further establishes the reduction in energy requirement and data packet loss through this optimal router placement strategy.     

Service task partition and distribution in star topology computer grid subject to data security constraints

The paper considers grid computing systems in which the resource management systems (RMS) can divide service tasks into execution blocks (EBs) and send these blocks to different resources. In order to provide a desired level of service reliability the RMS can assign the same blocks to several independent resources for parallel execution.The data security is a crucial issue in distributed computing that affects the execution policy. By the optimal service task partition into the EBs and their distribution among resources, one can achieve the greatest possible service reliability and/or expected performance subject to data security constraints. The paper suggests an algorithm for solving this optimization problem. The algorithm is based on the universal generating function technique and on the evolutionary optimization approach. Illustrative examples are presented.     

基于DSP的DES/3DES仿真及系统实现

数据加密标准/三重数据加密标准(Date Encryption Standard/3 Date Encryption Standard,简称DES/3DES)算法是一种分组加密算法,其实现原理简单,安全性能好。但是DES/3DES算法的密钥必须有一定的长度才能保证算法的安全性,所以计算量很大,用软件加密实现目标则速度较慢,只有改用硬件来实现此算法才能提高运算速度。DSP芯片提供的一种专用乘法器,可以提高完成DES/3DES算法的速度。结果表明,用TI TMSS320C55xDSP芯片,并辅以C语言来实现快速DES/3DES算法具有明显的优势。     

一种基于缓存交互的命名数据网络拥塞控制算法

研究了命名数据网络(NDN)的拥塞控制。为了解决突发流量问题和提高吞吐量及网络资源利用率,考虑了路由器缓冲区大小与拥塞控制机制的相互影响以及NDN内部署缓存这一重要特性,提出了一种基于缓存交互的NDN拥塞控制算法。该算法通过利用NDN中的路由器缓存,在逻辑上动态扩充缓冲区大小并控制Data包的发送速率,同时与现有的NDN拥塞控制算法相结合,动态调整Interest包发送速率阈值,以平滑突发流量,缓解网络拥塞。基于ndn SIM的仿真实验结果表明,该算法能有效提高NDN的传输效率、吞吐量和网络资源利用率。     

一种路由器多操作系统平台的设计与实现

为了实现路由器软件在操作系统间的移植,并且扩展原有操作系统的功能,设计和实现了一种路由器多操作系统平台(RMOS).该RMOS基于微内核体系结构,设计了统一的系统调用接口,它不仅隐藏原有操作系统的内部细节,还加强了内存操作的安全性,对系统资源进行监控,并为非实时操作系统虚拟了实时调用接口.通过使用RMOS,路由器厂商能够根据市场需求,提供基于不同操作系统的多性价比产品,同时大大降低软件移植的成本.目前,RMOS可在VxWorks和Linux上顺利运行.     

Cross-layer design for tree-type routing and level-based centralised scheduling in IEEE 802.16 based wireless mesh networks

Infrastructure wireless mesh network, also named as mesh router, is one key topology for the next generation wireless networking. In this work, the performance optimisation for the infrastructure wireless mesh network is presented and the sub-optimum solution mechanism is investigated. A cross-layer design for tree-type routing, level-based centralised scheduling and distributed power control theme is proposed as the sub-optimum solution strategy. The cross-layer design relies on the channel information and the distributed transmission power control in the physical layer, and the wireless scheduling in the medium access control (MAC) layer, as well as the routing selection mechanism in the MAC upper layer. In this work, a modified distributed power control algorithm is proposed first. In addition, a tree-type routing construction algorithm for centralised scheduling is presented to improve the network throughput by jointly considering interference and hop-count to construct the routing tree. Simulation results show that the proposed cross-layer design strategy can effectively improve the network throughput performance, decrease the power consumption and achieve better performances.     

异地协同设计制造关键技术及系统实现

 在分析制造业面临的新挑战以及网络化制造特点的基础上，提出了基于Web的异地协同设计制造系统的体系结构并开发了一个实际系统eCWS(e—cooperative work system )．详细介绍了该系统的功能和关键技术的实现，包括协同系统管理、协同工作管理、协同应用、约束管理和冲突消解、协同工具、安全控制、分布式产品数据管理等技术． 最后介绍了应用实例．     

Efficient Secure Data Provenance Scheme in Multimedia Outsourcing and Sharing

To cope with privacy leakage caused by multimedia outsourcing and sharing, data provenance is used to analyze leaked multimedia and provide reactive accountability. Existing schemes of multimedia provenance are based on watermarking protocols. In an outsourcing scenario, existing schemes face two severe challenges: 1) when data leakage occurs, there exists a probability that data provenance results can be repudiated, in which case data provenance tracking fails; and 2) when outsourced data are shared, data encryption transfer causes key management burden outside the schemes, and privacy leakage threatens users. In this paper, we propose a novel data provenance scheme with an improved LUT-based fingerprinting protocol, which integrates an asymmetric watermarking protocol, robust watermark algorithm and homomorphic encryption and digital signatures to achieve full non-repudiation provenance. We build an in-scheme stream cipher to protect outsourced multimedia data from privacy leakage and complicated key management. Our scheme is also lightweight and easy to deploy. Extensive security and performance analysis compares our scheme with the state of the art. The results show that our scheme has not only better provenance security and data confidentiality but also higher efficiency for multimedia outsourcing, sharing and provenance.