Nestor: Network Engineering System for TOpology and Requirements

Abstract: Many large organizations today have an interest in communications networks either as users of public networks or as operators of their own private networks. The environment in which networks operate is extremely complex and very dynamic. Users are becoming more sophisticated, hence, their demands for network services are increasing in complexity. The network technology is changing at an incredible rate, and there is a very large number of hardware and software vendors selling network products and services. In such an environment, network management is of vital importance, yet it is exceedingly difficult to accomplish effectively. Most organizations are finding that there is little available in the market in the way of comprehensive systems which address the complex problems encountered in planning and engineering communications networks. The purpose of this paper is to describe a development effort which treats one important aspect of network design—that of engineering changes in a network subsequent to the initial design. The result of this research is an expert system called Nestor (Network Engineering System for TOpology and Requirements) which is being used by AT&T network engineers to respond to user change requests for a large packet switching network—thirty network switches, fifty mainframe computers, and one hundred and forty thousand terminals and printers. Estimates based on initial experience with the system are that throughput of the engineering group will increase by 500% for network change requests assigned to Nestor.     

A knowledge-based approach to the local area network design problem

Computer networks are an essential tool for people in business, industries, government, and schools. With the rapid rate of change in network technology and products, and the emergence of highly sophisticated network users, network design has become an increasingly complex task. Although the computer society aims at agreeing to a series of international standards for describing network architectures, the design of a computer network remains an ill-structured problem that lends itself perfectly to expert systems solutions. We propose an expert system that is able to design local area networks meeting the requirements specified by the user. Rules and guidelines pertaining to local area network design are formulated and incorporated into the knowledge base. The system is built on an object-oriented paradigm. The object-oriented approach and the hierarchical rule structure paradigm are discussed. We also employ the blackboard technique through which rules can access dynamic objects conveniently.     

An integrated case-based reasoning approach for intelligent help desk fault management

As modern business functions become more complex and knowledge-intensive, with increasing demands for quality services, there is an emerging trend for organisations to develop and deploy intelligent knowledge-based systems for mission-critical operations. Some of the challenges in successfully implementing this breed of systems depend on how well the intelligent system is integrated with conventional existing information systems and workflow, and the quality of the intelligent system itself. Developing quality expert systems lies in the effective modelling of cognitive processes of human experts and representation of various forms of related knowledge in a domain. An integrated intelligent system called the Intelligent Help Desk Facilitator (IHDF), has been developed for computer and network fault management. The system, which comprises various modules including an expert system, is successfully deployed in a problem response help desk environment of a local bank. This paper describes a cognitive-driven approach to the development of the expert system based on a hybrid knowledge representation and reasoning strategy. The approach incorporates a hybrid case-based reasoning (CBR) framework of techniques which include case memory organisation structures (discrimination networks and shared-featured networks), case indexing and retrieval schemes (fuzzy character-matching, nearest-neighbour similarity matching and knowledge-guided indexing); and an interactive and incremental style of reasoning. The paper discusses the design and implementation of the expert system component of IHDF and illustrates the appropriateness of the hybrid architecture for problem resolution and diagnostic types of applications.     

TruSMS: A trustworthy SMS spam control system based on trust management

The fast growth of mobile networks has greatly enriched our life by disseminating information and providing communications at any time and anywhere. However, at the same time, when people gather and exchange useful information, they also receive unwanted data and contents, such as spam and unsolicited commercial advertisements. SMS (Short Message Service) spam is one typical example of unwanted contents, which has caused a serious problem to mobile users by intruding their devices, occupying device memories and irritating the users. More critically, some of these fraudulent messages deceive users and cause them incalculable loss. SMS spam control has become a crucial issue that impacts the further success of mobile networks. A number of researches have been conducted to control unwanted contents or traffic, some are based on trust and reputation mechanisms. But the literature still lacks an effective solution for SMS spam control. In this paper, we present the design and implementation of an SMS spam control system named TruSMS based on trust management. It can control SMS spam from its source to destinations according to trust evaluation by analyzing spam detection behaviors and SMS traffic data. We evaluate TruSMS performance under a variety of intrusions and attacks with a prototype system implementation. The result shows that TruSMS is effective with regard to accuracy, efficiency and robustness, which imply its trustworthiness.     

Datacab: a geographical-information-system-based expert system for the design of cable networks

Abstract: Telecommunication networks have evolved over time as a result of technological advances, and network topologies and equipment have become increasingly complex. Expert systems are being successfully applied to the management of telecommunication networks. However, applying expert systems to network design is another especially beneficial yet still not very common approach. In this paper we propose a rule-based expert system called Datacab. Datacab was developed at Enditel Endesa in collaboration with the Electronic Technology Department of the University of Seville, for the automatic design of hybrid fibre coax (HFC) cable networks. Using data from a geographical information system as input, it automatically generates viable HFC network designs.     

Hub location in backbone/tributary network design: a review

A common architecture for a communications network consists of tributary networks, which connect nodes to hubs, and a backbone network, which interconnects the hubs. Often, because of the size of the problem or the nature of the application, the design of the backbone network and the tributary networks are considered independently. However, in many cases, it is desirable or necessary to treat backbone and tributary design as an integrated problem, in which a key decision is the choice of hub locations. We provide a review of earlier algorithmic work on this integrated problem, drawing from the literature on facility location, network design, telecommunications, computer systems and transportation. Certain key issues in modeling hub location problems in the particular context of communications networks are discussed, and possible avenues for future work are proposed.     

Interworking of heterogeneous access networks and QoS provisioning via IP multimedia core networks

Moving towards packet networks, where IP will have a prominent role, constitutes nowadays a widely accepted perception of future communications, the first instance of which has begun to materialise with the IP multimedia core network subsystem (IMS). By specification, IMS is the first implementation towards reaching converged communications which allows users to communicate with video, audio and multimedia content, via any fixed, mobile and wireless access network type, with controllable QoS. To enable IMS communications across heterogeneous networks, incorporating UMTS, WLAN and fixed IP access points, 3GPP and ETSI’s TISPAN currently work on schemes for controlling bandwidth allocation at the service level by employing logical interfaces that carry SIP messages. This article analyzes how interconnection between such heterogeneous networks may be performed on real platforms. In this effort, special attention is paid to the way the various interconnection possibilities can affect end-to-end QoS provisioning.     

利用ATM技术建设的民航通信网络

目前,民航空管系统的通信网络主要是由平面通信网和地空通信网这两个互相独立的网络组成。文章以民航ATM网为主干,讨论了民航空管系统通信网络建设的发展方向即民航平面通信网和地空通信网互连、互通的可能性以及在技术上所遇到的挑战。展望了语音、数据、视频3网合1在民航通信网中的发展前景。     

Network review — Part 1

The above sections are based on a generalization of a large number of network reviews which have been performed. but the overall conclusion is that on the whole, local area networks are not subject to adequate controls and procedures and many organizations are exposed to significant business risks due to inefficient network management. We hold some sympathy for the network manager and support functions, as the growth of the network and associated technologies has been dramatic and the developers of the network operating systems have concentrated on the provision of tools for the users rather than the administrator. The good news is that some of the shortcomings of Network Operating Systems are now being addressed, As an example, Novell NetWare 4 is shipped with an excellent auditor function which will provide management with sophisticated audit trails which can be protected from access by the network administrator. NetWare 4.x also provides a single login to multiple NetWare servers which should relieve the administration effort required for effective user management. There is, however, no excuse for weak network security, this seems to be a common problem in many organizations and with the dramatic growth in the implementation of WAN links, modem links and Internet access, the risks of unauthorized access to systems and data is increasing by the day, Management should at the very best assess their exposure to these risks and stress the importance of network security not only to the users but also to the network management and support functions.This article has concentrated on the management, support and security of computer networks which traditionally encompass a network review. In the next issue, the additional stages of the Touche Ross network review will be discussed which primarily focuses on the review of network resilience and reliability which is beginning to be seen as a critical factor of an organization's business. Network downtime can now be directly associated with financial losses to an organization and as such should be of a key concern to their senior management and the computer audit function.     

基于LonWorks的嵌入式网络监控系统的设计

设计了一种基于LonWorks总线和嵌入式系统的监控通信网络。系统采用MSP430单片机作为任务调度和嵌入式系统移植的主处理器,提高了系统运行的实时性和稳定性。DDE服务器实现了数据访问与交换等网络通信功能。总线技术与Web网络相结合,使用户能够通过信息网络监控界面方便地了解现场情况,更便于实现远程监控、诊断和维护功能。     

A novel trust management scheme based on Dempster–Shafer evidence theory for malicious nodes detection in wireless sensor networks

With the development of Internet technology, social network has become an important application in the network life. However, due to the rapid increase in the number of users, the influx of a variety of bad information is brought up as well as the existence of malicious users. Therefore, it is emergent to design a valid management scheme for user’s authentication to ensure the normal operation of social networks. Node trust evaluation is an effective method to deal with typical network attacks in wireless sensor networks. In order to solve the problem of quantification and uncertainty of trust, a novel trust management scheme based on Dempster–Shafer evidence theory for malicious nodes detection is proposed in this paper. Firstly, by taking into account spatiotemporal correlation of the data collected by sensor nodes in adjacent area, the trust degree can be estimated. Secondly, according to the D–S theory, the trust model is established to count the number of interactive behavior of trust, distrust or uncertainty, further to evaluate the direct trust value and indirect trust value. Then, a flexible synthesis method is adopted to calculate the overall trust to identify the malicious nodes. The simulation results show that the proposed scheme has obvious advantages over the traditional methods in the identification of malicious node and data fusion accuracy, and can obtain good scalability.

     

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.     

基于策略优化的计算机网络管理技术研究

随着网络技术的快速发展,基于IP应用的传输在未来的网络中占据优势地位这一点已经变得明显了。与此同时,波分复用设备已经足够成熟,能提供很高网络容量(太比特网络传输),这将是一直增长的信息量所需要的。本文描述了专门设计用于光因特网(IPoverWDM)的基于管理体系的策略。在最近一段时期,基于计算机网络管理的策略问题已经成为研究热点。提出了一种管理系统方案,可实现管理系统集成,以便于系统管理、网络管理和管理应用的协作。     

分布式网络安全管理系统的研究

网络的发展已经越来越趋向于大规模发展,分布式网络得到了广泛的应用,其信息安全成为当前网络安全的主要问题之一。本论文针对网络安全管理系统的应用现状,讨论了分布式网络安全管理系统的设计,从系统架构、安全策略以及安全构建技术三个角度给出了分布式网络安全管理系统的设计方案,对于进一步提高分布式网络安全管理系统的研究与应用水平具有一定借鉴意义。     

基于桥梁用户的多社交网络影响最大化

单社交网络影响最大化问题已经得到了学术界的广泛关注与研究,然而如今多社交网络之间呈现信息互通的趋势.多社交网络中存在的桥梁用户（Bridge User,BU）（即同时拥有多个社交网络账户的用户）,可将信息从一个社交网络分享至另外一个社交网络,信息传播不再局限于单个网络.本文针对多社交网络信息影响最大化进行了相关研究,分析了桥梁用户在多社交网络信息传播中的作用,提出了基于桥梁用户的多社交网络聚合算法,并在得到的聚合图上对多社交网络影响最大化问题进行求解.仿真实验对多社交网络影响最大化问题进行了求解,并证实了桥梁用户在多社交网络信息传播时的作用.     

运用Web Service技术构建专家系统之间的交互

专家系统解决问题的范围常常受到知识领域狭窄的限制。Web Service实现了“基于Web无缝集成”的目标,可以运用Web Service技术来实现专家系统之间的交互,弥补专家系统知识不足的问题。文中运用Web Service提供的技术构建网络上专家系统之间的交互,并且对这种交互的可行性进行了分析研究,这就不仅为解决专家系统知识不足的问题提供了方法和技术,而且进一步构建了一个模型,使得网络上专家系统互相协作,共同解决一个领域更广的问题。     

Enforcing Efficient Equilibria in Network Design Games via Subsidies

The efficient design of networks has been an important engineering task that involves challenging combinatorial optimization problems. Typically, a network designer has to select among several alternatives which links to establish so that the resulting network satisfies a given set of connectivity requirements and the cost of establishing the network links is as low as possible. The Minimum Spanning Tree problem, which is well-understood, is a nice example.In this paper, we consider the natural scenario in which the connectivity requirements are posed by selfish users who have agreed to share the cost of the network to be established according to a well-defined rule. The design proposed by the network designer should now be consistent not only with the connectivity requirements but also with the selfishness of the users. Essentially, the users are players in a so-called network design game and the network designer has to propose a design that is an equilibrium for this game. As it is usually the case when selfishness comes into play, such equilibria may be suboptimal. In this paper, we consider the following question: can the network designer enforce particular designs as equilibria or guarantee that efficient designs are consistent with users’ selfishness by appropriately subsidizing some of the network links? In an attempt to understand this question, we formulate corresponding optimization problems and present positive and negative results.     

网络管理专家系统研究

网络的高速发展使网络的规模越来越大，复杂性越来越高。网络技术日新月异。这对网络管理提出了更高要求。网络管理专家系统被证明能够比较较好的解决网络管理领域中的一些问题，如系统的动态怀，协作管理等。本文分析了网络管理专家系统的特性，提出了开发网管专家系统时应注意的一些问题。最后提出了一具网络管理系统的结构，并进行了分析。     

Double-sided auctions applied to vertical handover for mobility management in wireless networks

In the next generation Internet, we have seen the convergence of multimedia services and Internet with the mobility of users. Vertical handover decision (VHD) algorithm are essential components of the mobility management architecture in mobile wireless networks. VHD algorithms help mobile users to choose the best mobile network to connect among available candidates. It also can help the network manager to optimize easily the limited resources shared among the network providers and the users. In this article, we formulate VHD algorithm as a resource allocation problem for down-link transmission power in multiple W-CDMA networks and show how combinatorial double-sided auctions can be applied to this specific problem. The proposed pricing schemes make use of the signal interference to noise ratio, achievable data rates, power allocation at mobile networks, and monetary cost as decision criteria and our model differentiate between new calls and on-going communications to take into account that the last category has somewhat more importance. Several combinatorial double-sided auction are proposed to maximize the social welfare and /or to provide incentives for mobile users and mobile operators to be truth-telling in terms of valuation or cost. Finally, the economic properties of the different proposed pricing schemes are also studied by means of simulations.     

基于误码率与中断概率约束的femtocell网络分布式功率控制

家庭基站(femtocell)网络可有效改善无线通信业务的室内覆盖性能,提高信道容量.然而,复杂的动态通信环境导致信道的不确定性,影响用户服务质量.基于此,研究双层femtocell网络在快衰落信道环境下基于误码率约束的功率控制问题;考虑信号传输的中断概率,以及服务质量指标–误码率等方面的要求,构造在此约束下的优化问题;最大化双层femtocell网络的净收益,使得网络系统的通信性能最优;通过对概率约束进行数学处理,将其转化为确定性形式,并提出分布式鲁棒优化算法对等价的确定性优化问题进行求解,从而获得最优功率分配策略.最后,通过仿真验证了所提出算法的收敛性和有效性.