面向城域网的新型弹性分组数据环技术

弹性分组数据环技术集IP的智能化、以太网的经济性和光纤网的高带宽效率和可靠性于一体,为宽带IP城域网运营商提供了一个良好的组网方案。本文介绍了RPR的技术特点、标准化与产业化进展情况,重点讨论了各种RPR提案中已经基本达成共识的关键技术。     

EXFO推出模块化多业务传输网测试仪

EXFO推出手持式现场测试仪系列的最新创新产品——FTB-880 NetBlazer多业务测试仪和FTB-810x NetBlazer系列传输网测试仪。FTB-880 NetBlazer是一款强大、全面、迅速的测试模块．可满足速率高达10Gbit／s的DSn／PDH、SONET/SDH和分组以太网服务测试要求。     

互连网发展过程

互连网在近几年已经得到飞速发展,从早期的用DDN专用线路互连路由器阶段发展到ATM交换网互连带ATM SAR（分割及拼接）接口的路由器阶段,目前已经进入MPLS网络阶段,本文简要介绍了互连网经历的这三个发展阶段,讨论了它们的性能特点。     

A high-speed four-channel subscriber fibre-optic link for broadband networks

This paper describes the performance of a 560 Mb/s digital fibre-optic link designed specifically for possible use in a broadband integrated services digital network (BISDN) environment. Four 140 Mb/s non-return-to-zero (NRZ) channels are time division multiplexed using a bit-by-bit multiplexing strategy and transmitted using potentially low cost 1.3 μm EE-LED and laser sources. A 10^?9 bit error rate with a power level of -34 dBm was achieved for each independent channel over a distance of 10 km.     

光数据网探索

通过描述一条包含了多种数据网协议的光数据网通路，探讨了一种新的网络趋势，同时讨论了几种数据网协议以及光数据网的网络结构。     

基于MPLS的透明局域网服务

主要介绍了基于多协议标记交换（MPLS）技术的透明局域网服务（TLS）。详细分析了TLS业务流穿过MPLS网络时标记帧所发生的变化，并着重阐述了一种优化MPLS标记头的方法，使服务提供商能在基于MPLS的网络中扩展现有服务，从而提供具有QoS和流量工程的TLS服务。     

Simulation-based SONET ADM optimization approach for dynamic traffic grooming in WDM optical networks

The article addresses a simulation-based optimization approach for allocation of ADMs in WDM optical networks with stochastic dynamic traffic. Since ADMs are expensive, it is desirable that if each node in WDM optical networks can use a minimum number of ADMs to achieve a near-ideal performance. In this article, first, the utilization statistics of ADMs are gathered by simulation. Then, ADMs are allocated based on the utilization statistics. In this respect, a simple sorting mechanism is used. The distinguished feature of the proposed approach is that it shows the way to allocate ADMs at the nodes of WDM optical networks with stochastic dynamic traffic. The experimental results ensure that the proposed approach can solve the problem of allocating ADMs in practical WDM optical networks considering stochastic dynamic traffic.

国际SDH的发展及我们应采取的策略

同步数字序列(SDH)已成为国际通信标准,并日渐为世界各国所注目。本文给出了SDH的标准化进程、各国SDH的发展简况和过渡策略,以及我国引进SDH的情况,最后就我国发展SDH应采取的策略及方针提出了看法。     

宽带网传输中具有故障保护的高性能开关探讨

ITU-T与ANSI在SDH/SONET标准方面的进展，加快了世界各国在传输系统上的改造。其先进的OAM功能可用于建立起具有故障保护的自愈环网络，这种自愈环包括分插复用器（ADM）。ADM中的开关在其自愈环工作中起着重要作用，本文为确定其对ADM开关的需要，分析了自愈环结构与原理。在此基础上，介绍了能明显减少硬件数量的新的空分交换方法。     

Concurrent Support of Higher-Layer Protocols over WDM

To satisfy the severe requirements involved in future communication networks, commercial and research interest in the applicability of wavelength division multiplexing (WDM) is growing. However, since WDM is merely concerned with transmitting bits over optical fibers, full advantage can only be taken when WDM is efficiently supported by higher-layer protocols. Functionality of higher-layer protocols that could be used in conjunction with WDM originates from synchronous digital hierarchy (SDH) or synchronous optical network (SONET), asynchronous transfer mode (ATM), and the internet protocol (IP). To provide flexible use of services with different levels of quality, various higher-layer protocols may directly support WDM simultaneously by reserving wavelength channels for a specific supporting protocol. Focussing on aspects of network management, this paper investigates how the mentioned higher-layer protocols may concurrently support WDM.