Computer Networks

Networks of computers are making it possible to achieve computer-to-computer and terminal-to-computer communications that only a few years ago would have been impossible. Many of these networks are operational already, with more powerful ones seemingly in store for the future. This remarkable growth has opened new opportunities for designers, users, and managers–but it has posed some difficult problems for them as well. Knowledge of such network issues as topological design alternatives, common carrier communications services, value-added networks, hardware and software networking technology, cost factors, regulatory issues, measurement techniques, and network administration are of paramount importance. Hence this special issue.     

浅谈计算机网络中的数据加密

介绍了数据加密的基本原理,较为详细地对对称数据加密技术、非对称数据加密技术及公开密钥的数据加密技术的数据加密方式及其应用进行了探讨。     

Operating Systems for Computer Networks

The last decade has seen the rapid evolution of computer communication networks from research curiosities to operational utilities. The Arpanet,¹for example, currently supports communication among more than 100 computer systems and is used daily by hundreds of users. Commercial networks, such as Telenet²in the United States and Datapac³in Canada, have very bright futures. One attraction of these networks is their ability to provide access to a wide variety of resources distributed among the connected computers.     

论计算机网络立法研究

随着计算机网络应用的不断推广,它给人类带来了巨大的社会效益和经济效益的同时,也改变着人类社会的生产方式和人们的生活方式,网络犯罪现象也开始逐步出现,而在此当中,最为突出严重的问题就是计算机犯罪.本文从网络犯罪的概念和原因,网络犯罪的构成要件及计算机保护的立法现状,结合计算机发展趋势提出一些建议.     

计算机网络虚拟实验教学模式探讨

随着科学技术的不断发展,作为传统实物实验教学补充的计算机网络虚拟实验教学已经成为提高教学质量、加强学生实践能力的重要手段。本文主要介绍了计算机网络虚拟实验教学模式实施的必要性、局限性以及在实施当中应注意的问题。     

A Standard for Computer Networks

The development of suitable standards is a vital key to developing ing the full potential of multi-access computer networks. To date work is being done on only a few of the standards that will be required, and among these few, progress is distressingly slow. Divergent procedures are rapidly becoming entrenched in areas where there should be standards and if the current rate of standards development is extrapolated, it is doubtful that the necessary standards can be developed in time.     

高职非计网专业计算机网络课程教学改革探讨

以计算机网络技术作为课程改革的对象,通过对这一课程在非计算机网络专业中教学现状及存在的主要问题的分析,结合在教学中的实践,提出了一些观点和思考,进行了计算机网络课程的教学改革,对高等职业技术院校的教学改革做了有益的尝试.     

中小企业计算机网络的构建

该文针对如何构建中小企业网络的问题,给出了一个方法,还就如何解决网络过程中的设备选型,网络速度,防毒防黑等问题,给出了一些自己的想法。     

浅谈计算机网络故障及维护

该文对网络的故障进行了分类,提出了解决网络故障的一般步骤,常用工具,并对常见网络故障进行了诊断和处理。     

计算机网络中的分级保密通信

可信计算组织TCG[1]提出了一系列技术规范,但该组织没有考虑密钥的分级问题。文献[2]解决了密钥的分级问题,但同一级别用户通信时使用同一个密钥,一个级别的任一用户同另一个低级别的任一用户通信也用级别低用户(所在类)的密钥,在某些情况下,这是我们不希望的。本文给出两种方法,用这两种方法,某一级别的用户能主动与同级别的用户或级别低的用户进行保密通信,且用的密钥是不同的,而不能主动与级别高的用户进行保密通信。     

浅议计算机网络的有效维护

随着电脑的广泛普及,人们在不知不觉地走进了互联网时代,然而网络却在很多方面存在着安全的因素。本文就是从互联网存在的哪些危险因素来分析,从而探讨出一些有效的措施来维护网络的安全。     

探析计算机网络的信息安全防护

网络发展至今,早已想到超出了人们当时的想象,计算机网络的应用范围也已经延伸到了国计民生的各个领域,并且还呈现不断扩大的趋势.特别是在金融领域的应用已经越来越深入,而凸显出来的信息安全问题也日渐严重.本文针对这一问题做了详细的分析探讨.     

实时计算机网络的有效带宽

文章通过剖析实时计算机网络研究中“有效带宽”定义的内涵与外延,阐明了它在介质访问仲裁、逻辑链路控制、确定性排队、保证概率排队等应用领域中的意义与用法;并指出了根据大偏离原理(LargeDeviationPrinciple,LDP)定义的有效带宽不仅从概念上反映了多时间尺度和空间尺度下网络的统计复用情况,而且具有带宽的量纲。通过有效带宽与流量过程的累积量生成函数(CumulantGeneratingFunction,CGF)的关系,给出了将大偏离原理应用于流量整形变长数据包流量的方法,并根据随机序(stochasticordering)理论提出了一种“4状态7参数”模型作为这种整形数据流的随机性能界限。通过对CGF函数在空间尺度上求极限,得到最大流率函数,揭示了LDP框架下,保证概率(guaranteeingprobability)意义下到最坏条件下(theworstcase)实时性能保证具有一致的语义。     

Topological Design of Centralized Computer Networks

Topological design of centralized computer-communication networks is an important issue that has been investigated by a large number of researchers. Such networks typically involve a large number of terminals connected by low or medium speed lines to concentrators, which are then connected to a central computing site by high speed lines. This problem is known to be a very difficult one. In general, the design problem involves determining the following: (a) the numbers and locations of concentrators that are to be opened; (b) the topology of connecting user nodes to concentrations sites; and (c) determining the links between open concentrators and the central node. Since the overall design problem belongs to the class of problems that are NP Hard, most prior research has investigated ways in which to disaggregate the problem into several simpler problems that can be solved iteratively until a satisfactory solution is reached. The problem we solve is this research involves multipoint lines between terminals and concentrators, and dedicated lines between concentrators and the central node. This problem therefore combines features of concentrator location problems as well as local access network design problems. We utilize a Lagrangian heuristic designed to efficiently solve this problem with gap ranging from 2.7 to 10.4% of the lower bound.     

计算机网络信息安全与防范

随着计算机信息技术的飞速发展,计算机网络已广泛用于经济、军事、教育等各个领域。计算机网络在带来海量信息的同时,由于网络的开放性和自由性也产生了私有信息和数据被破坏或侵犯的可能性。因此,网络信息的安全性变得日益重要起来。对目前计算机网络存在的安全隐患进行了分析,并探讨了针对计算机安全隐患的防范策略。