SunOS下基于一次性口令和封装保护的网络安全设计与实现

多数网络守护神的实现很少考虑全球性访问的卷入问题,在某些情形下,这样的访问可允许灵敏信息的全球发布,如加密口令。在其它情形下,运行在网络任何地方的进程都会引起局部变化。针对可能出现的这些问题,在SumOS环境下,在防火墙上实施一次性口令认证以及封装保护措施,主些措施实现起来比较容易,而且可增强网络的安全性。     

Fractal: A mobile code-based framework for dynamic application protocol adaptation

The rapid growth of heterogeneous devices and diverse networks in our daily life, makes it is very difficult, if not impossible, to build a one-size-fits-all application or protocol, which can run well in such a dynamic environment. Adaptation has been considered as a general approach to address the mismatch problem between clients and servers; however, we envision that the missing part, which is also a big challenge, is how to inject and deploy adaptation functionality into the environment. In this paper we propose a novel application level protocol adaptation framework, Fractal, which uses the mobile code technology for protocol adaptation and leverages existing content distribution networks (CDN) for protocol adaptors (mobile codes) deployment. To the best of our knowledge, Fractal is the first application level protocol adaptation framework that considers the real deployment problem using mobile code and CDN. To evaluate the proposed framework, we have implemented two case studies: an adaptive message encryption protocol and an adaptive communication optimization protocol. In the adaptive message encryption protocol, Fractal always chooses a proper encryption algorithm according to different application requirements and device characteristics. And the adaptive communication optimization protocol is capable of dynamically selecting the best one from four communication protocols, including Direct sending, Gzip, Bitmap, and Vary-sized blocking, for different hardware and network configurations. In comparison with other adaptation approaches, evaluation results show the proposed adaptive approach performs very well on both the client side and server side. For some clients, the total communication overhead reduces 41% compared with no protocol adaptation mechanism, and 14% compared with the static protocol adaptation approach.     

无线网络中的一种基于小世界模型的路由协议

最近,利用节点的移动性提升网络系统性能的方法引起了不少关注。这些方法已经被运用于包括移动Adhoc网络（MANET）、无线传感网络（WSN）和容忍延时网络（DTN）在内的一些新兴网络中,他们都认为节点是随机或者可控移动的。为了达到优化或平衡包括延时、平均中继节点数目和移动距离在内的一些度量参数的目的,本文提出了一种基于于小世界模型的路由协议（SWR）。通过分析,该协议只有多对数数量级的中继节点,大大减少了报文传输过程中中继节点的数量。文中定义了短链接与长链接的概念,其中每一节点与其最邻近的节点之间存在“短”链接,而与其他遵循桌一概率分布的节点间存在着“长”链接。短链接通常是无线链接,而长链接通常是利用移动节点来实现的。本文在网络规模、使用数据搭乘者、多重长链接和等待移动节点时间方面进行了分析。通过仿真结果,我们对各方面性能进行了评估。     

一种移动节点无线传感器网络路由算法的优化设计

在深入研究ZigBee协议的基础上,提出了一种更适合于链式移动网络的路由算法EmBee,分析了其工作原理及协议软件的实现流程,并给出其性能测试结果.实践证明,EmBee作为一种移动无线传感网络路由算法,具有协议简单、代码量少、自组网能力强、传输跳跃速度快等特点,在无线链式、扇形移动网络内有更好的效果.     

Service discovery in mobile ad hoc networks: A field theoretic approach

Service discovery in mobile ad hoc networks is challenging because of the absence of any central intelligence in the network. Traditional solutions as used in the Internet are hence not well suited for mobile ad hoc networks. In this paper, we present a novel decentralized service discovery mechanism for ad hoc networks. The basic idea is to distribute information about available services to the network neighborhood. We achieve this by using the analogy of an electrostatic field: A service is modelled by a (positive) point charge, and service request packets are seen as (negative) test charges which are attracted by the service instances. In our approach, we map the physical model to a mobile ad hoc network in a way where each network element calculates a potential value and routes service requests towards the neighbor with the highest potential, hence towards a service instance. Our approach allows for differentiation of service instances based on their capacity. We define the required protocols and methods which we implemented in a network simulator. Using extensive simulations, we evaluate the performance and robustness of the mechanisms. The results indicate good performance and convergence even in highly mobile environments. We believe that this technique can and should be further exploited, e.g., as a routing protocol in mobile ad hoc networks.     

Ad Hoc网络中一种基于环状分层结构的组密钥协商协议

移动ad hoc网络是一种新型的移动多跳无线网络.其自身的特征,如网络规模庞大、动态的拓扑结构、有限的计算、通信和存储能力等,使得传统的密钥分配和管理机制无法直接应用于该网络.提出了一种新的适用于移动 ad hoc网络的组密钥协商协议.该协议在环状分层结构上基于多线性映射进行组密钥的协商和分配,使得节点在密钥协商过程中具有低计算开销与低通信开销的优势,较好地解决了在移动ad hoc网络中进行组密钥协商时所遇到的节点能量受限问题,适用于移动ad hoc网络.     

车载自组织网络路由协议的仿真研究

本文简要介绍了车载自组织网络和移动自组织网络中两个典型的路由协议:表驱动路由协议DSDV和按需路由协议AODV;还介绍了一个实用的移动模型,使仿真实验更加接近现实。在Linux下使用网络仿真工具NS2对这两个典型协议进行仿真,并对仿真结果进行分析比较和性能评价,得出:AODV和DSDV协议都不太适用于车辆自组织网络,所以设计适合车辆网路的协议是急需解决的问题。     

基于移动代理的QoS多播路由技术研究

随着大量新型的多媒体在高性能网络、移动网络及Internet中的应用,满足QoS约束的多播路由协议越来越重要.针对目前多播路由协议无法同时满足可扩展性和高成功率,提出了一种新的以移动代理为基础的QoS多播路由协议(MAQMR).该方法允许多播协议在移动代理间实现并在代理所访问的每个结点得到动态应用.不同于单播路由,移动代理以并行和分布形式协作方式来构建多播树,同时使消息开销最小化并满足QoS要求.     

无线传感器网络的NS2扩展与仿真机制研究

分析了NS2的工作原理和仿真机制,重点介绍了分裂对象模型和离散事件调度模型.以无线传感器网络作为重点,阐明了NS2对无线传感器网络的扩展机制,包括节点能耗模型扩展、移动节点扩展以及相应路由协议扩展.在此基础上,介绍了NS2仿真传感器网络路由协议的代码调用过程及仿真模型,并以分簇路由协议LEACH为实例进行了仿真实验,从...     

Experiences building a communication‐oriented JavaOS

Mobile code makes it easier to maintain, debug, update, and customize a system. Active networks are one of the more interesting applications of mobile code: code is injected into the nodes of a network to customize the network's functionality, such as routing, and to add new features, such as special‐purpose congestion control and filtering algorithms. The challenge is to develop a communication‐oriented platform for such systems. We refer to mobile code targeted at low‐level, communication‐oriented systems like active networks as liquid software, the key distinction being that liquid software is focused on the efficient transfer of data, not high‐performance computation. To this end, we have designed and implemented Joust, which consists of a complete re‐implementation of the Java virtual machine (including both the runtime system and a just‐in‐time compiler), running on the Scout operating system (a configurable, communication‐oriented OS). The result is a configurable, high‐performance platform for running liquid software. We present the results of implementing two different applications of liquid software on Joust, including a prototype architecture for active networks. Copyright © 2000 John Wiley & Sons, Ltd.     

EGAKA:一种面向LTE-A机器类型通信的高效组认证与密钥协商协议

机器类型通信(Machine Type Communication,MTC)作为物联网的基础,有着广阔的市场和应用前景。LTE-A网络能够为MTC的发展提供有力的支持,第三代合作伙伴项目(3rd Generation Partnership Project,3GPP)已经在3GPP标准Release10中正式定义了MTC。与普通的移动用户设备相比,MTC设备具有数量多、功耗低的特点,这给LTE-A网络的身份认证问题提出了新的挑战。当大量MTC设备同时接入网络时,如果每个设备都进行独立的身份认证过程,则会导致LTE-A网络出现严重的信令拥塞问题。同时,MTC设备由于计算资源有限,不宜做大量的运算。针对MTC网络中设备认证过程的信令拥塞问题,提出了基于聚合代理签名和消息认证码的组认证与密钥协商协议EGAKA。该协议采用聚合代理签名使得LTE-A网络可以同时验证多个MTC设备,并最小化认证过程中的信令开销。采用消息认证码的方法进行密钥协商,有利于降低MTC设备的计算开销。通过着色Petri网(Colored Petri Nets,CPN)的建模和分析,证明该协议能够正确完成认证和密钥协商。另外,通过在性能方面与文中引用的协议比较,证明该协议在信令开销和计算开销方面具有一定优势。     

移动自组网中一种面向群组移动性的位置服务协议

基于位置信息的路由协议被广泛认为是一种可扩展的移动自组网路由解决方案.大多数此类协议假定可通过位置服务协议获取结点的位置信息.研究人员现已提出多种位置服务协议.但是,它们在大规模网络环境中的可扩展性不好,或者在高动态网络环境中可靠性不高.本文提出了一种适用于大规模移动自组网的面向群组移动性的可扩展及可靠的位置服务协议.模拟结果表明此协议比SLURP协议更适合于具有群组移动性的大规模移动自组网.     

Mobility information for resource management in wireless ATM networks

User mobility poses a significant technical challenge to network resource management in wireless ATM (Asynchronous Transfer Mode) networks. In order to guarantee quality of service (QoS) to mobile users and to achieve a high efficiency in network resource management, the information of mobile users' handoff at a future moment is essential for statistical multiplexing. This paper develops a novel fuzzy logic inference system to estimate the user mobility information for a wireless ATM network which uses a direct sequence code division multiple access (DS/CDMA) protocol. The estimation is based on measured pilot signal strengths from a number of the nearest base stations by the mobile user. Numerical results are presented to demonstrate the performance of the proposed technique under various path losses and channel shadowing conditions. The proposed technique can achieve simplicity, accuracy and low cost.     

一种基于移动Agent的异构网络管理模型

分析了集中式网络管理方法的局限性,介绍了移动Agent的特点及与传统方法相比的优势,提出了一种针对异构网络的基于移动Agent的网管模型,详细地介绍了该模型的设计思想、结构、管理方式及安全性、容错性、独立性等特点。设计实现了两种移动Agent:故障诊断代理和故障搜索代理。使用它们评估和验证了移动A gent管理实际的异构网络的能力,它们能够在一个特定大小的网络中准确定位故障并分析故障的原因。     

基于实验床(Testbed)的DSR协议的性能评价

DSR犤1,2犦协议是一种用于无线Adhoc网络的路由协议。笔者在Linux操作系统下实现了DSR路由协议,并以此为基础,搭建了一个无线Adhoc网络的实验床(Testbed)。在实验床的真实场景中,笔者从路由性能、协议开销和TCP业务的传输性能三个角度对DSR协议进行了一系列实验和性能评价工作。论文对该实验床的搭建和所得到的性能测试的结果进行了介绍。实验中,发现在无线多跳Adhoc网络的环境下,TCP业务的性能很差,此外也给出了对这种现象的解释。     

基于移动代理的主动网络

在介绍主动网络的基础上,提出了一个在移动代理系统基础上建立的安全而高效的主动网络系统框架MANet(mobile agents based active network).通过将程序代码和数据封装成主动数据包在主动结点上作为代理来运行,这个框架实现了集成化的主动网络,并且通过基于CodeBroker的代码装载和缓存技术改善了整个主动网络的性能和灵活性.     

The SATIN Component System-A Metamodel for Engineering Adaptable Mobile Systems

Mobile computing devices, such as personal digital assistants and mobile phones, are becoming increasingly popular, smaller, and more capable. We argue that mobile systems should be able to adapt to changing requirements and execution environments. Adaptation requires the ability-to reconfigure the deployed code base on a mobile device. Such reconfiguration is considerably simplified if mobile applications are component-oriented rather than monolithic blocks of code. We present the SATIN (system adaptation targeting integrated networks) component metamodel, a lightweight local component metamodel that offers the flexible use of logical mobility primitives to reconfigure the software system by dynamically transferring code. The metamodel is implemented in the SATIN middleware system, a component-based mobile computing middleware that uses the mobility primitives defined in the metamodel to reconfigure both itself and applications that it hosts. We demonstrate the suitability of SATIN in terms of lightweightedness, flexibility, and reusability for the creation of adaptable mobile systems by using it to implement, port, and evaluate a number of existing and new applications, including an active network platform developed for satellite communication at the European space agency. These applications exhibit different aspects of adaptation and demonstrate the flexibility of the approach and the advantages gained     

Protecting mobile code in the world

Proposed applications for mobile code systems include autonomous shopping agents, autonomic systems, distributed sensor network applications, and interstellar space networks. I argue the case for mobile code systems as the next-generation distributed programming paradigm and discuss the security problems that must be addressed before this vision is practically realizable. The security discussion will focus on protecting mobile code programs that execute in the wild from malicious actions by remote hosts.     

基于嵌入式Linux的移动通信终端的实现

在嵌入式Linux操作系统下,利用GPRS技术无线通信的优点,结合GPS全球定位技术和地理信息系统技术,给出了一个对移动终端进行导航与监控的具体实现方案,并进行了实际移动终端的设计;移动终端接收GPS定位信息,通过GPRS网络发送到监控中心,出于终端实际应用硬件资源和代码可移植性等方面的考虑,主要完成了定位数据的接收、GPRS模块的控制、PPP协议和TCP/IP协议的实现、矢量地图的绘制和人机交互。     

一种基于方向天线和时间同步机制的多信道无线网状网MAC协议

在城市小区和广阔的农村建立低成本的无线网状网,为无线终端用户提供高速的接入服务,是一项极具现实意义的工作.设计了一种适合于此类网络的MAC层协议称为Mesh-MAC,该协议建立在已有的IEEE 802.11硬件产品基础上,每两个节点之间的通信是由一对方向天线完成,通过一种全新的时间同步方案,可以实现M ESH网内高效的数据转发.仿真结果表明,与IEEE 802.11及2P协议相比,Mesh-MAC协议在吞吐量和端到端传输延时等方面,都有明显的改善.