软交换技术在电力通信中的应用探讨

由于软交换既能执行基于硬件的传统电话交换机相同的功能,又能同时处理IP通信,轻松整合电路交换和分组交换,一时间成为电信行业中倍受青睐的时髦用语.以Internet为代表的分组交换网络的兴起,立足于分组交换网络上构建下一代网络能够统一向用户提供数据、语音、视频等多媒体综合业务,成为业界的共识.本文将对软交换技术在电力通信中的应用进行分析.     

电信软交换中继网关建设方案及网络演进策略

软交换是NGN的关键技术,在传统的电信交换网络中,引入软交换技术进行网络的优化和演进是必然趋势.本文介绍了传统PSTN本地网中,引入中继网关,替代汇接局和长途局的建设方案,对于探讨软交换网络的建设具有借鉴意义.     

软交换与PSTN本地网融合组网方式初探

软交换在骨干网应用的成熟性毋庸置疑, 但引入本地网后,由于端局的复杂性, 与原有PSTN 网络合理的组网方式,正成为拥有PSTN 网络的传统电信运营商关注的重点。采用叠加网的发展策略,在初期,通过接口局或汇接局实现软交换网络与PSTN 的互通;在中远期,随着PSTN 用户逐步迁移到软交换网络,实现以软交换为核心、多种接入方式并存的融合本地网络的目标,是探索方向之一。对此进行的实践和心得,对当前各大电信运营商正在进行的本地软交换实验网或商用试验网建设不无裨益。     

本地网智能化的实现

本地网智能化,就是通过改造让原有的固定网络具有智能化的处理能力,提高网络业务触发能力和网络服务水平,实现号码资源的灵活配置.全网智能化的核心思想是:全网所有的呼叫都由智能网进行控制并集中计费,所有本网用户的数据信息都由智能网集中管理维护(类似于移动网络中的HLR),交换机则更加专注于基础的接续、业务触发等能力的提升.在这种新的建网模式下,交换机和智能网各自的职能更加明确,业务的创新和使用不再受到分散在各地的交换端局物理线路和物理号码的制约.     

软交换技术在福建电力行政网中的应用

软交换是指以软交换设备为控制核心的下一代网络,其把呼叫功能从媒体网关中分离出来,通过服务器上的软件实现基本呼叫控制功能,从而实现呼叫传输和呼叫控制分离,能轻松整合电路交换和分组交换、降低网络成本,给用户提供更多的个性化的服务,顺应企业的发展要求。文章从对传统程控交换机和软交换技术的分析着手,探讨了福建电力行政网络现状与软交换技术的应用,并对电力行政交换网络今后的发展作了展望。     

大唐集团新型本地网解决方案

1电信市场和环境的变化 传统本地网是指在一个长途编号区内由若干交换机(端局与汇接局)、传输(局间中继、长市中继)、接入网及用户线所组成的自动电话交换网.传统本地网建设、运维成本高,建设时需要挖沟埋缆,建设周期长,网络维护困难.在业务运营时,由于用户数据不集中,用户更改业务属性时需要对多个交换局的数据进行修改,实现业务融合与多个业务间捆绑营销困难,很难实现机号分离,很难提供开放的API和业务平台,引入第三方的增值业务提供商,实现产业链的共赢.     

M3UA代理和转发模式的探析

随着软交换技术的发展,核心网各网元间的通信主要基于IP来实现,为了实现网元在传统电路交换网与IP交换网间的通信,就引入了信令网关及协议适配的概念。本文以第三代移动通信核心网中的第三层用户适配协议为研究对象,笔者根据近几年移动核心网络改造、建设、分析及维护工作的经验出发,从这两种模式的工作原理及应用场景,对比它们的优缺点,论证了M3UA转发模式必将逐渐代替M3UA代理模式,在今后核心网络的应用中更具优势和前景。     

菏泽本地网华为交换机并局组网实施方案

针对目前移动用户及软交换用户大力发展,传统PSTN用户在逐渐萎缩,本方案针对本地网内同一型号华为交换机进行并局组网,进一步深化网络瘦身,提升网络运行质量。     

关于固定电话网HLR的探讨

中国电信最大的优势是固定电话网,而同时最大的包袱也就是固定电话网的改造和演进。以低成本、高起点为主题分析如何对中国电信庞大而陈旧的交换网进行改造;以“网络收敛”的主线思想,探讨了从“交换功能集中”到“用户数据集中”的网络优化模式,提出了实现交换智能化的方案。2003年常州本地网完成了以汇接局为交换核心和功能核心的本地网一级汇接结构,并进一步实现了交换集中化、端局模块化。2004年进而引入了固定电话网HLR,实现了用户数据集中。     

基于软交换的网络管理

随着电信市场的变化和下一代网络的演进，软交换技术正成为电路交换网络和分组交换网络走向融合的技术纽带。软交换作为主干网的中继接入网关，从网络管理的角度看，它必须同时满足分组网和电路交换网关技术的要求，其中包括简单网络管理协议（SNMP）、电信管理网（TMN）、公共     

Providing Multiple-Channel Communication Using the Experimental Digital Switch

This report describes the functional characteristics of a circuit-switched network which is capable of providing data communication paths as well as voice channels. In the system described, the circuit switch may be shared in order to provide multiple independently switched paths through the network. Unlike a conventional circuit switch, this sharing permits only a fraction of the switching capacity to be consumed which is proportional to the allocated bandwidth of the path. Additional economy is gained by providing multiple communication paths over the single communication resource between the subscriber and the switching machine. The fraction of the communication resource which is used by the subscriber is proportional to the total bandwidth of the channels which have been allocated. This allocation is performed dynamically, in response to subscriber requests. Algorithms are presented which perform this allocation efficiently. The resulting network provides a communication vehicle which provides both data and voice services in an integrated fashion.     

Progress Towards Digital Subscriber Line Services and Signaling

With digital connectivity, future subscribers will be able to exercise local and network services involving the routine delivery, management, and processing of information. Accelerated by rapidly advancing technology, the evolutionary process towards digital connectivity and integrated voice and data services in the network is underway. This paper describes the methods of integrating voice and information capability into the telecommunications network. The attributes of this network will include the availability of digital connectivity directly to the subscriber, the availability of a robust signaling means between the subscriber and his local switching office, and common channel signaling to implement all interexchange signaling. Issues of interest include an overview of digital subscriber connectivity, signaling and information structures for these kinds of lines, communications protocols, and general network considerations for the provision of information services. Partitioning of intelligence between intelligent subscriber terminals and controllers and their switching system is investigated. The use of message and virtual channel switching facilities to handle limited information rate services is discussed. Finally, an exploratory digital subscriber line under investigation at Bell Laboratories is described.     

Switching System Software Design for ISDN

The ISDN offers various services through multipurpose digital subscriber lines. The switching program for the ISDN should be so designed as to realize the control of various voice and nonvoice services and provide for developing service enhancement. To attain the goal, the ISDN services are classified hierarchically and each category is allocated to appropriate network nodes for implementation. As a result, the local switching program provides an out-slot subscriber line signaling capability and call connection with appropriate compatibility checking including a check for access capability to communications processing nodes. The switching program modules specific to analog services and those specific to digital services are separated to allow the use of the existing program file and to afford easy program design and maintenance. Remote-controlled switching is a suitable means for an economical introduction of the ISDN services to low traffic density areas. Special routing and reliability arrangements as well as the program structure for a remote-controlled switch are discussed.     

The Effects of Management Traffic on the Local Call Processing Performance of ATM Switches Using Queue Network Models and Jackson's Theorem

This paper considers a TMN‐based management system for the management of public ATM switching networks using a four‐level hierarchical structure consisting of one network management system, several element management systems, and several agent‐ATM switch pairs. Using Jackson's queuing model, we analyze the effects of one TMN command on the performance of the component ATM switch in processing local calls. The TMN command considered is the permanent virtual call connection. We analyze four performance measures of ATM switches—utilization, mean queue length and mean waiting time for the processor directly interfacing with the subscriber lines and trunks, and the call setup delay of the ATM switch—and compare the results with those from Jackson's queuing model.     

Loop Test System: A New Maintenance Feature for the Distributed Integrated Digital Network

The introduction of the digital Class 5 switch offers unique solutions to the requirements of growth and demands for improved service. For example, remote subscriber switches (RSS's) and subscriber carrier terminals (SCT's) can now be located near subscribers and digitally connected to the Class 5 switch via T1 repeatered lines or radio links. The result is shorter subscriber loops, improved transmission, and deferment or elimination of feeder plant additions. Traditionally, interposing electronics between the subscriber loops and the Class 5 switch resulted in isolating these loops from the office loop testing facilities. Remote testing of RSS and SCT assigned loops is an important step toward minimizing maintenance costs. Loop testing is accomplished in TRW Vidar's ITS5 switching system by locating loop test equipment in the remote RSS and SCT cabinets. This equipment is available to the test operator for real-time testing, and to the switch for automatic line testing. Some of the requirements that the loop test equipment must meet are: low cost, no adjustments, low power consumption, small size, operation in a harsh environment, and centralized testing capability from a test console. The data returned to the office must be in a quantitative form to allow further processing by the console. It must also be compatible with the direct distance dialing (DDD) network to allow transmission not only to the Class 5 switch serving the RSS and SCT, but also to distant service centers. This paper describes a newly developed system that meets the above objectives.     

Electrostatically driven fiber-optic micromechanical on/off switchand its application to subscriber transmission systems

The structural design of the switch element is evaluated theoretically and experimentally, and an optimum combination of membrane length and insulator thickness is obtained. Based on the results, a 32-element electrostatically driven switch array is fabricated; its switching performance was found to be excellent. The switch array is applied to a subscriber transmission system using an abnormal subscriber end. A disturbance light from an abnormal subscriber end is successfully interrupted     

A high capacity metropolitan area network using lightwavetransmission and time multiplexed switching

The technical feasibility of a lightwave communication system capable of providing service to thousands of subscribers within cities or large suburban areas is examined. Each subscriber in this system has available upon demand an aggregate bit rate of up to 100 Mb/s. The aggregate bit rate of the entire network is on the order of 5 Tb/s. The network topology is that of a star-on-star wherein each subscriber line terminates on one of a multitude of remote concentrators. Each high-speed link from a remote concentrator to a centrally located time-multiplexing photonic switch consists of a single-mode fiber carrying several wavelength-division multiplexed (WDM) channels. Each channel operates in a time-division multiplexed (TDM) mode at a data rate of 2 Gb/s and is powered by a multimode laser. No regeneration is required at the central switch, and at the remote concentrators, each channel is terminated by a direct-detection receiver. The approach achieves high throughput by reusing the same channels, that collectively occupy a tiny fraction of the optical band, among all interconnecting links and, with the exception of large-dimensional switch arrays, employs readily available technology     

光开关及其在全光网中的应用

光开关是完成全光交换的核心器件 ,光开关的研究日益成为全光通信领域关注的焦点。从光开关的性能指标开始系统介绍了光开关的类型 ,深入探讨了光开关构成的全光交换机的结构原理。随着数据网络的迅速发展 ,光开关将在全光网络中得到广泛的应用     

广东省宽带通信网建设及其发展的考虑

本文介绍了广东省宽带通信网的建设方案和设想，提出应根据ＡＴＭ交换技术的发展状况逐步发展ＡＴＭ交换网。在接入网方面，ＡＤＳＬ因具有较好的性能价格比且可以利用现有电视用户配线，成为目前较为理想的接入网产品；ＨＦＣ网络则不失为在农村地区的一种经济、灵活的发展模式。ＩＴＶ业务与宽带数据通信是目前宽带通信网的主要应用，它们的发展趋势是走向融合。     

Packetized Service Integration Network for Dedicated Voice/Data Subscribers

This paper describes a new integrated service network using packetized voice/data technology which was developed in consideration of the sophisticated service demands for voice, data, and facsimile communication. A major problem in constructing this network is in the local distribution network, i.e., the subscriber interface unit, the local end office, and the subscriber loop which connects them. The concepts, choice of design parameters, and laboratory test results of the packetized service integration network are briefly discussed.