Specifying telephone systems in LOTOS

A method for detecting feature interactions in the design of telephone systems using LOTOS (language of temporal ordering specifications) is described. The specification discussed includes call forwarding on a busy line, setting a three-way call, and call waiting. The ways in which a specification of a telephone system involving such features can be constructed in LOTOS and the ways in which LOTOS tools can be used to detect unwanted interactions of the features are illustrated using simple examples. The techniques used are step-by-step execution, symbolic execution, and compositional execution with test processes     

Specifying interdependence in networked systems

Realistic assessments of the reliability of networked systems, series and parallel systems being special cases, require that we account for interdependence between the component life-lengths. The key to doing this is the specification and use of a suitable probability model in two or more dimensions. Consequently, several multivariate probabilistic models have been proposed in the literature. Many of these models have marginal distributions that are exponential; the ones by Gumbel, and by Marshall and Olkin being some of the earliest and the best known. The purpose of this paper is two fold: The first purpose is to articulate the nature of dependence encapsulated by such models, using a perspective which is best appreciated by a user. Specifically, we anchor on the bivariate case, and focus attention on the conditional mean as a measure of dependence. The second purpose, motivated by the first, is to introduce a new family of multivariate distributions with exponential marginals, whose conditional mean fills a void in the general forms of the conditional means of the available models. The method of "copulas" is used to generate this new family of distributions. Attention is focused on the case of exponential marginals, because the notion of "hazard potentials" enables us to use multivariate distributions with exponential marginals as a seed for generating multivariate distributions with marginals other than the exponential.     

子网级大容量异构网络管理研究

通过对构建大容量异构网络管理系统面临的主要问题进行研究,文章提出了在分治服务架构方式下,基于进程的动态可伸缩软件架构。采用嵌套分层的业务管理模型和对象动态内存管理技术,解决了子网级大容量异构网络管理的主要问题。     

Realtime network management support systems at NTT

This paper describes realtime network management support systems which have been developed forntt’s telephone network. In particular, the advanced traffic observation and management information collecting system referred to as Atomics and the traffic congestion control system referred to astcs are presented. The purpose of the development, concept, functions and capabilities of each system are explained. Examples of powerful realtime network management supported by Atomics andTSC are also presented.     

GPON网管系统ONU端告警管理的设计

文章首先介绍了千兆无源光网络(GPON)的网络管理系统的结构,然后分析了网管中子代理光网络单元(ONU)的功能,重点讨论了ONU在管理与控制过程中出现的告警情况,并对其进行了分类.在此基础上对告警管理的处理方案进行了设计,完成了ONU管理控制模块中启动失败(SUF)告警进程的设计.     

The computational object approach for network and systems management

In the past 20 years, Network and Systems Management (N&SM) has thrived on mostly centralized or weakly distributed paradigms. Advances in technologies and software engineering suggested new ways of doing N&SM. The computational object approach is one of the main management technologies that have recently appeared. Based on this approach, the architecture proposed in this paper uses programming concepts instead of protocol concepts and conceals protocol complexity by easily manipulated components. Concerning the information model, the Common Information Model (CIM) is used which is designed in an object-oriented manner that is the key behind scalable N&SM.The implementation is done in the Windows environment and using the C++ programming language.     

A control and management network for wireless ATM systems

This paper describes the design of a control and management network (orderwire) for a mobile wireless Asynchronous Transfer Mode (ATM) network. This mobile wireless ATM network is part of the Rapidly Deployable Radio Network (RDRN). The orderwire system consists of a packet radio network which overlays the mobile wireless ATM network. Each network element in this network uses Global Positioning System (GPS) information to control a beamforming antenna subsystem which provides for spatial reuse. This paper also proposes a novel Virtual Network Configuration (VNC) algorithm for predictive network configuration. A mobile ATM Private Network–Network Interface (PNNI) based on VNC is also discussed. Finally, as a prelude to the system implementation, results of a Maisie simulation of the orderwire system are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

IP网管系统面临的两个转变

在IP网逐步真正成为电信级承载网络的过程中,IP网络管理就一直成为业内谈论和研究的热点之一。纵观IP网管的发展历程,可以大致看到两种不同的产品研发思路:横向发展的网管系统和纵向发展的网管系统。所谓横向发展就是追求统一管理平台,按照一种扁平化的视图结构来满足网管的全部功能,典型的产品有HP OPENVIEW、IBMTIVOLI和CA的UNICENTER TNG。纵向发展就是按照垂直方式,从业务、网络、网元的角度,实现某一特定管理域的功能。典型的产品有专注于故障管理的Micromuse公司的Netcool和专注于流量流向管理的Concord等。从实际的…     

Rule-based expert systems for network management and operations: anintroduction

The functions that can be performed by an integrated communication network management expert system are identified. Expert systems are defined, and knowledge representation, knowledge acquisition, and inference engines are discussed. A sample application problem using OPS5 is presented     

Dynamic memory management methodology applied to embedded telecom network systems

Presents a new methodology for dynamic memory management of embedded telecom network systems. This methodology enables the designer to further raise the abstraction level of the initial system specification and to achieve optimized embedded system designs. This methodology is well suited for systems characterized by a set of concurrent and dynamic processes, very high-bit-rate data streams, and intensive data transfer and storage, as encountered in telecom network applications. Up to now, it has been successfully applied to four telecom network systems. This methodology can be easily integrated into any C++-based system synthesis approach that bridges the gap between a concurrent process-level system specification and an optimized (for area, performance, or power) embedded implementation of communicating hardware/software processors. This is in contrast to current system design practice, where VHDL/C is derived without room for exploration, refinement, and verification, leading to expensive late design iterations. In this paper, the main focus lies on the system-level specification model and the dynamic memory management applied to two real-life telecom network systems.     

两种网络安全管理系统的生存性定量分析方法

虽然通信网络生存性分析技术已经发展多年,但对大量的通信网络之上的各种分布式应用系统,如网络安全管理系统(NSMS)的生存性评估技术尚无有效的方法。本文提出两种评估NSMS生存性的方法。第一种方法建立基于数据流的图模型,通过图的连通性计算生存性。第二种方法建立基于数据流的过程模型,通过Monte Carlo实验数据的统计估算生存性。我们的经验表明:随着网格技术的发展,第二种方法用于复杂系统的生存性定量分析是可行的。     

如何选择高性能电缆

对于现在极其复杂精密的电子产品,必须要避免电缆故障。人们已根本无法接受哪怕是短暂的停机,谁也不能承受比使用寿命提前几年就要更换的昂贵的机械设备,尤其是当利润空间很小,竞争又格外激烈的时候。     

Specifying communications DACs

The explosion in the market for digital communications equipment has fostered unprecedented interest in high performance DACs and highlighted the shortcomings in the way in which these devices are described. The authors discuss the architectures and features of DACs together with specifications (dynamic and static) and signal distortion. Comparisons of DACs are also mentioned.     

Specifying software requirements

Many of the problems of software system development can be traced to poor understanding or specification of what the system is supposed to do. Much attention is now being given to producing requirements specifications that are understandable, formal, complete, and modifiable. The structure and content of conceptual models for problem understanding are discussed; such models can form the basis for requirements analysis. Techniques for "tuning" and formally specifying the conceptual model are surveyed, and the proper scope of a software requirements document-including nonfunctional requirements such as performance-is explained.     

Getting proactive network management from reactive network management tools

Typical network management tools fail to prevent network outages and downtime. Network managers can set up proactive network management with existing tools, using SNMP automatic actions, triggered by thresholds. © 1998 John Wiley & Sons, Ltd.     

基于策略的网络安全管理

安全管理优势明显安全管理是网络管理的重要组成部分。传统的安全管理主要依靠管理员的经验,专注某些具体的安全目标和网络实体。管理员先要对防火墙、虚拟专用网(VPN)服务器等网络实体进行配置,相应的安全目标由这些网络实体来实现。而这些网络实体只具备某一部分安全功能,整个网络的安全目标需要所有网络实体共同协作来实现。因此,如何保护数据在网络中安全传输、维护服务器的安全、确保用户的合法性都需要一个从整体到部分的安全策略来管理。另一方面,互联网技术的飞速发展和广泛应用使得网络的规模更加庞大,网络系统的复杂性和异构性…     

光传输网管海量数据存储访问研究

文章主要针对光传输网管系统中网无数量急剧增长导致的网管数据库更新查询效率极低,甚至出现系统崩溃的问题,提出了一种高效的分布式数据库系统架构.该系统采用主从技术、Memcached技术与分布式数据库结合的方式,将数据分散地存储在多台独立的设备上,提高了数据的查询效率.系统容量大、可靠性高、扩展能力强,具有很强的实用性.     

Experiences with goal-oriented modeling of organizational change

In today's business environment of relentless change, the topic of how one should proceed with understanding the reasons for change and alternative strategic options, has received much attention by researchers and practitioners alike. This paper considers the relation between goal-oriented business process modeling and organizational change and addresses the question "how can we reason about organizational change using a goal-driven approach?" To this end, it describes a systematic way-of-working for modeling organizational change and presents empirical results and observations from applying this approach in a large industrial application in the domain of utility deregulation. The purpose of this paper is twofold. Firstly, to demonstrate and assess the applicability of the proposed methodology on a nontrivial application and secondly to illustrate a number of challenging issues that need to be addressed by goal-driven methodologies in order to effectively support the process of change.