天津通信电信管理网网络管理系统的设计与实现

本重点论述如何为基于TCP／IP的计算机网络“量身定做”网络管理系统。首先介绍了网络管理的定义、网络管理体系结构。天津通信电信管理网是天津通信公司为了实现对本地电话网程控交换机的远程监控和集中操作维护而构建的计算机广域网络系统。本深入讨论了天津通信电信管理网网络管理系统的设计与实现。     

Consumer communications and networking [guest editorial]

A technology that is increasingly visible in the consumer communications domain is peer-to-peer (P2P) communications networks. This is due not mainly to illegal downloads or file sharing, but much more to large-scale consumer communications and distributing contents among subscribers. The main advantage of P2P overlay networks over client-server-based systems is that they do not require central server components; and with respect to management and maintenance, P2P systems are self-managing, in that they can cope with nodes leaving and joining even at a high churn rate. Moreover, P2P systems are very scalable and can cope with a large number of nodes. Typically P2P systems operate as an overlay network on top of the IP layer.     

A protocol for partitionable group membership service in mobile Internet

The explosive growth of mobile and wireless communications has attracted interests in the integration of mobile and wireless networks with wired ones and the wired Internet in particular. Such an integrated mobile Internet environment has brought up many new applications and there is an increasing demand for enhanced services to help users do mobile collaborations, which requires the support for mobile group communications. In this paper, based on a multitier proxy‐based mobile Internet architecture, we propose a novel scalable, reliable, and partitionable membership protocol for mobile group communications. The proxies manage local groups of mobile users and are dynamically organized into a ring‐based hierarchy for global membership management. We describe algorithms and mechanisms for membership propagation and topology maintenance in the presence of dynamic membership, dynamic locations of mobile hosts, and dynamic networks. The proposed protocol can tolerate proxy failures, and network failures including network partitions and network merges. Theoretical analysis and simulation studies show that, comparing with existing tree‐based protocols, the proposed protocol has comparable scalability and higher reliability. Copyright © 2005 John Wiley & Sons, Ltd.     

现代电信网运行维护的技术支持系统

在电信网达到一定规模，网路建设速度放慢之时，在设备 应商的名费技术支持到期后，数千万端口多种型号的交换设备和大量传输设备的技术支持由谁来承担？中国电信将采用什么策略 技术手段来保障维护部门能及时得到优质高效的技术支持？本文作者长期从事本地网网管和集中监控系统的开发和工程实施，深深感到与网管配套的运行维护技术支持系统在电信支撑网的建设中的重要性。     

Mobility management protocols for next-generation all-IP satellite networks [architectures and protocols for mobility management in all-IP mobile networks]

To provide ubiquitous terrestrial Internet coverage mobility and Internet-based access to data generated by satellites, there is a strong desire to integrate the terrestrial Internet and satellite networks. This requires satellites that are based on IP for communications. Rotation of low Earth orbit satellites around the Earth results in communicating with different ground stations over time, and requires mobility management protocols for seamless communication between the Internet and satellite networks. In this article we provide a comprehensive summary and comparison of state-of-the-art research on mobility management schemes for satellite networks. The schemes are based on network and transport layers for managing host and network mobility. This article clearly indicates the aspects that need further research and which mobility management schemes are the best candidates for satellite networks.     

Development of an integrated network manager for heterogeneousnetworks using OSI standards and object-oriented techniques

The Federal Aviation Administration (FAA) is using an increasing number of interconnected, heterogeneous telecommunications networks. The FAA is looking at new ways of automating the operations and maintenance activities of these networks in a cost-effective manner in a rapidly changing environment. Open system interconnection (OSI) standards provide a structure for dealing with multivendor systems and network management problems, including mechanisms for monitoring, controlling, and coordinating resources, as well as protocol standards for communicating information about these resources. An example of a standards-based open system for network and services management is a prototype system being developed by the Center for Advanced Aviation System Development (CAASD) and the FAA for managing telecommunications networks and services at Air Route Traffic Control Centers (ARTCCs). This system, the Telecommunications ARTCC Prototype (TAP), is being developed to integrate the various existing communications management capabilities at the ARTCC into a single management system. Following OSI standards and object-oriented techniques provides a concept and structure for a distributed management architecture. The syntax and semantics for management information and functions specified in the standards provide an understanding and definition of the operations to be performed and the information to be collected and communicated. The paper provides an overview of the prototype architecture, describes how OSI standards and object-oriented techniques were applied and interpreted to meet the specific requirements of the ARTCC     

Mobility management in current and future communications networks

This article describes current and proposed protocols for mobility management for public land mobile networks (PLMNs), Mobile IP, wireless ATM, and satellite networks. The integration of these networks is discussed in the context of the next evolutionary step of wireless communications networks. First, a review is provided of location management algorithms for PCS implemented over a PLMN. The latest protocol changes for location registration and handoff are investigated for Mobile IP, followed by a discussion of proposed protocols for wireless ATM and satellite networks. Finally, an outline of open problems to be addressed by the next generation of wireless network service is discussed     

VSAT Networks—an overview

This paper examines the technology and constraints of very small aperture terminals (VSAT) networks, a special type of wide-area thin-route satellite network that represents a recent innovation in the field of satellite communications. VSAT network architectures suitable for both data and voice communications are studied in this paper. Several issues concerning the frequency of operations, that is, C-band versus Ku-band are examined, and trade-offs between non-spread spectrum and spread spectrum techniques, as well as modulation and multiple access schemes, are considered in detail. Link design examples are given to illustrate the performance of various types of VSAT networks.     

Integrated network management in an enterprise environment

Various aspects of integrated network management for business enterprises are discussed. Two categories of communications resources are considered: those that provide interfacility networking, such as circuit-switching or packet-switching telecommunications networks, and those that provide intrafacility networking, such as some form of local area network. The topics covered include: the network management environment within an enterprise; network management elements; the requirements for enterprise network management; a basic architecture for integrated network management; value-added services that expert system modules can provide; current approaches; and possible migration strategies for achieving integrated network management     

Tree-type photonic switching networks

The enormous bandwidth offered by optical systems makes photonic switching a very attractive solution for broadband communications. Tree-type architectures play an important role in the design of photonic switching networks. The authors present and discuss all known tree-type space-division photonic switching networks architectures in a unified framework, and propose a number of new solutions. The discussed networks can be implemented with guided-wave-based switching elements, or laser diodes and passive splitters and combiners. The following network types are considered: conventional, simplified, and two-active stage networks. Techniques for improving SNR as well as waveguide crossover minimization are presented and discussed     

面向异构网管理的多级中间件体系

为了减少异构网网络管理方面所付出的代价，继续利用各专业子网已有的网络基础设施并对其进行跨域管理，提出了一种多级网络管理体系。该体系模型以面向对象、中问件技术为核心．利用CORBA的IDL接口封装网元层元素，将本地各专业子网抽象为分布式对象，使用CORBA平台完成对象问的互连。中问层使用CORBA/Web Services复合代理，上层则由Web Services直接联入Intemet。授权用户可在Intemet任意一点应用GUI终端（浏览器）访问网络系统，对异构网下层网元元素进行网络管理。     

地铁通信系统的集中告警

集中告警设备利用计算机网络技术和计算机本身的高速数据处理能力,对城市轨道交通中地铁通信各系统进行集中监测告警管理。将通信各系统网络及设备的运行状态和告警信息集中反映到告警设备上,可及时、准确、迅速地获取设备的运行状态信息,以便维护人员快速、准确处理各系统设备故障。并可形成统一的综合管理报表,从而提高通信网络的维护质量和管理水平。     

基于车辆行为分析的智能车联网关键技术研究

车联网通信系统中通信节点的高移动性、移动行为的复杂性,使得此场景下通信业务呈现数据实时交互性强、空时分布不均、尺度多变、规律复杂的特征,导致传统的车联网网络部署、资源调配难以有效满足用户的差异化服务质量需求。因此,迫切需要设计“车-人-路-云”泛在互联的智能异构车联网网络,通过充分挖掘车辆行为数据的潜在价值,精准预测、刻画车辆行为的空时分布特性,以提升车联网资源利用率、改善车联网服务性能。该文全面梳理了国内外在车辆行为分析、网络部署与接入以及资源优化方面的相关工作,重点阐述了智能车联网关键使能技术,即如何借助先进的人工智能、数据分析技术,探索车联网中车辆行为的空时分布特性,建立车辆行为预测模型,进行智能化网络部署与多网接入、动态资源优化管理,实现高容量、高效率的智能车联网通信。     

动力环境集中监控系统在移动通信网维护管理中的应用

阐述了移动通信动力设备和环境维护管理工作中面临的问题，并介绍了江苏省移动公司在这方面开展的研究工作，重点对动力环境集中监控系统在移动网维护管理工作中的应用作些探讨。     

Towards autonomic management of communications networks

As communications networks become increasingly dynamic, heterogeneous, less reliable, and larger in scale, it becomes difficult, if not impossible, to effectively manage these networks using traditional approaches that rely on human monitoring and intervention to ensure they operate within desired bounds. Researchers and practitioners are pursuing the vision of autonomic network management, which we view as the capability of network entities to self-govern their behavior within the constraints of business goals that the network as a whole seeks to achieve. However, applying autonomic principles to network management is challenging for a number of reasons, including: (1) A means is required to enable business rules to determine the set of resources and/or services to be provided. (2) Contextual changes in the network must be sensed and interpreted, because new management policies may be required when context changes. (3) As context changes, it may be necessary to adapt the management control loops that are used to ensure that system functionality adapts to meet changing user requirements, business goals, and environmental conditions. (4) A means is required to verify modeled data and to add new data dynamically so that the system can learn and reason about itself and its environment. This article provides an introduction to the FOCALE autonomic network management architecture, which is designed to address these challenges.     

The theory of connecting networks and their complexity: A review

Connecting networks are key subsystems of communications switching systems. This paper reviews what is known about the theoretical minimum complexity of connecting networks of several different types and presents the best known explicit constructions for them. In some cases, such as for strictly nonblocking connection networks, there is a significant difference between the best known construction and the theoretical minimum complexity. In other cases, such as for rearrangeably nonblocking connecting networks, the best construction differs from the minimum by only a constant.     

Group key management scheme for large-scale sensor networks

Wireless sensor networks are inherently collaborative environments in which sensor nodes self-organize and operate in groups that typically are dynamic and mission-driven. Secure communications in wireless sensor networks under this collaborative model calls for efficient group key management. However, providing key management services in wireless sensor networks is complicated by their ad-hoc nature, intermittent connectivity, large scale, and resource limitations. To address these issues, this paper proposes a new energy-efficient key management scheme for networks consisting of a large number of commodity sensor nodes that are randomly deployed. All sensor nodes in the network are anonymous and are preloaded with identical state information. The proposed scheme leverages a location-based virtual network infrastructure and is built upon a combinatorial formulation of the group key management problem. Secure and efficient group key initialization is achieved in the proposed scheme by nodes autonomously computing, without any communications, their respective initial group keys. The key server, in turn, uses a simple location-based hash function to autonomously deduce the mapping of the nodes to their group keys. The scheme enables dynamic setup and management of arbitrary secure group structures with dynamic group membership.     

Backbone Topology Synthesis for Multiradio Mesh Networks

Wireless local area network (WLAN) systems are widely implemented today to provide hot-spot coverage. Operated typically in an infrastructure mode, each WLAN is managed by an access point (AP). Wireless mesh networks (WMNs) are employed for the purpose of extending the wireless coverage scope by interconnecting the underlying AP nodes. The capability and performance behavior of the WMN can further be upgraded by using multiple communications channels and by having more capable nodes use multiple radio modules. In this paper, we present a fully distributed multiradio backbone synthesis algorithm, which serves to construct a mesh backbone network of APs. We assume more capable nodes, such as APs, to be equipped with two radio modules, while less capable nodes employ a single radio module. Multihop communications among distant client stations take place in accordance with a routing algorithm that uses the mesh backbone to establish inter-WLAN routes. The presented backbone construction algorithm and the associated on-demand backbone-based routing mechanism are shown to improve the system's delay-throughput performance, as well as its asynchronous and distributed behavior in a stable fashion     

面向NGN的运营支撑系统

传统电信网以网络运行维护为中心，而下一代网络（NGN）是以分组交换为主的网络，采用开放的网络架构体系，其运营支撑以客户为中心。立足于在NGN运营维护系统建设上以客户为中心，以市场为导向，以效益为目标，中出通讯在NGN网络上实现了完整的覆盖各个功能层次的网管系统，并且建设在统一的运营支撑维护系统平台之上，能够灵活地进行技术升级以适应技术演进的需要，为运营商提供了新的面向客户的服务。     

Design of an optimal BER monitoring scheme for preventive maintenance of an ATM network

In today's telecommunication networks it is well known that unexpected failures in the physical links may cause significant loss or interruption of services. It is desirable if the deterioration of links can be recognized early and maintenance is carried out before failure occurs. Asynchronous transfer mode (ATM) networks have recently received much attention and are considered to be the prime universal networks of the future. Unfortunately, there has been very little research in the areas of preventive maintenance and performance monitoring of the ATM network. In this paper we propose a preventive maintenance monitoring scheme for an ATM network where a performance index called the bit error rate (BER) index of each service of the ATM network is continuously monitored. The BER index of each path in the ATM network is assumed to be slowly deteriorating and is modelled as a Brownian motion process with positive drift. If any of the BER indices exceeds its action limit or threshold, a repair process is initiated. The optimal action limit is derived by minimizing the modified long-run average maintenance cost. We found that the optimal action limit depends strongly on the multiservice characteristics of the ATM network and on the network topology, which relates to the virtual path (VP) bandwidth management and routing protocol used. To obtain the optimal action limit, an optimization model for VP bandwidth management is set up and the multidimensional Erlang loss model is used to determine the path selecting probabilities. Some numerical examples are given to illustrate the proposed model and the optimization results. © 1998 John Wiley & Sons, Ltd.