A high-speed-retry banyan switch architecture for giga-bit-rate BISDN networks

This paper proposes a high-speed ATM switch architecture for handling cell rates of several Gb/s in a broadband communication switching system or cross-connect system. The proposed switch architecture, named the high-speed-retry banyan switch, employs a bufferless banyan network between input and output buffers; a cell is repeatedly transmitted from an input buffer until it can be successfully transmitted to the desired output buffer. A simple cell-retransmission algorithm, is employed as is a ring-arbitration algorithm for cell conflict. They are suitable for FIFO type buffers and bufferless highspeed devices. Good traffic characteristics which are independent of switch size are achieved for an internal speed ratio of only four times the input line speed. A prototype system with the internal speed of 1·2 Gb/s is constructed in order to confirm the basic operation of the high-speed-retry banyan switch. The prototype system, even in its present state, could be used to realize a giga-bit-rate BISDN switching system.     

An object-oriented analysis of a BISDN control system with a focus on the UNI protocol object

The control system of a BISDN network will undoubtedly be very complex to design, implement and maintain. Its complexity has led researchers to look for ways of breaking down the problem into smaller and manageable parts. This has motivated the use of an object-oriented approach to analyse and comprehend the BISDN control system. This paper thus presents an object-oriented analysis (OOA) of a BISDN control system. This analysis is based on a method introduced by Coad and Yourdon and comprises five steps. All five steps, namely identifying subjects, identifying objects, identifying structures, defining attributes, and defining operations, will be worked out in detail with an emphasis on the user network interface (UNI) signalling protocol object. Four subjects, nine objects, and three structures are identified in the problem space at hand. This structuring offers a framework to analyse in detail the three aspects, data, structure and dynamic behaviour, of the UNI signalling protocol. A parallel between this approach and the well known approach used by the International Telecommunication Union (ITU) for specifying signalling protocols and contained in Recommendation I.130 is drawn. The Coad and Yourdon OOA approach applied to a BISDN control system can be used for the analysis of different aspects of such systems. This paper focuses on the UNI signalling protocol object which leads to a complete specification. Any protocol resulting from such analysis can be claimed to be object-oriented protocol. This approach offers modularity and thus offers a way of structuring the problem space into identifiable objects and data. Full benefits of object orientation can be gained only in the consistent use of object orientation throughout all steps in the development process. The proposed approach allows one to create libraries of generic procedures which can be reused in specific implementations.     

ATMUNI信令的功能划分

ＡＴＭ用户－网络接口（ＵＮＩ）信令采用ＯＳＩ的分层结构,本文首先简要介绍了ＡＴＭＵＮＩ信令协议的体系结构以及各层的功能。然后详细描述了ＵＮＩ信令功能模块的划分,以及各模块的功能。     

B—ISDN的基本概念与标准化

本文首先介绍了宽带综合业务数字网(B—ISDN)的概念,继而引入ATM的概念;阐述了B—ISDN的基本原理、特点及标准化;最后明示了B—ISDN有待研究解决的几个问题。     

International standards for the broadband ISDN user-network interface

Recently, a series of international standards on broadband ISDN were approved in CCITT Study Group XVIII. These standards establish fundamental details on transmission, multiplexing and switching for broadband aspects of ISDN. This article reports on the current definition of the BISDN user-network interface. The UNI reference configuration, physical medium, rates, structure, ATM functions, and operations and maintenance functions are addressed with consideration given to open issues and the direction of future standards activities. Objectives for the UNI capabilities have generally been met with the current CCITT specifications. Some of the UNI physical layer ‘options’, however, potentially impose networking cost penalties.     

异步转移模式交换机中OAM功能的实现

本文深入地讨论了ＡＴＭ（Ａｓｙｎｃｈｒｏｎｏｕｓ ｔｒａｎｓｆｅｒ ｍｏｄｅ，异步转移模式）交换机中ＶＰ连接的故障管理与性能管理问题，并在此基础上对已有的ＶＰ－ＯＡＭ实现方案做了合理的改进。     

Management of capacity and control in broadband ISDN

The trend towards integration of services onto a single network and the addition of accompanying control features has led to an increase in the complexity of functional signalling protocols. A continuing dramatic reduction in the cost of traffic-carrying capacity has meant that call control costs are becoming an increasingly significant component of the total network cost. In BISDN, the support of many diverse services may result in an excessive control cost. To avoid this potential problem, virtual paths may be used. Capacity may be reserved on virtual paths to simplify the set-up procedure for individual calls. One benefit of this approach is that the cost of establishing a virtual path is shared among all individual connections which subsequently use it. However, this reduced control cost comes at the expense of installing additional traffic carrying capacity. This paper describes techniques for the management of traffic carrying capacity and control mechanisms in BISDN and presents a cost-benefit analysis to determine policies for reserving capacity on virtual paths. Significant savings in the total BISDN cost can result from the use of virtual paths.     

B—ISDN宽带UNI信令点到多点配置的实现

本文根据ＩＴＵ－Ｔ最新的Ｑ．２９７１协议，以及笔者所从事的实际课题，提出一整套Ｂ－ＩＳＤＮ第三层ＵＮＩ信令的软件实现策略，其特点是能同时满足用户对点到点以及点到多点广播这两种通信方式的要求，而且可以动态配置。     

A BISDN customer access architecture optimized in relation to network implementation technology

This paper aims at identifying an architecture model for a fibre-optic-based customer access network optimized at the minimum cost for the implementation technology and passive components inserted between the distribution centre and the subscriber premises. The optimization has been carried out on the basis of technical and economic considerations by taking into account the technology and market trends foreseen in this field. Moreover, a prediction of the cost reduction trend in the short-and medium-term scenario (up to 1995) has been derived for both the various passive components and the overall network implementation costs.     

多协议标签交换网络的OAM机制研究与实现

多协议标签交换技术MPLS是可扩展的下一代网络的关键承载技术,为了保障其传输数据质量不依赖于其他服务层,需为其提供独立的OAM机制。文中基于Y.1711协议分析MPLSOAM的基本功能及实现。重点研究MPLSOAM报文传输功能,通过在系统中添加OAM报文转发模块实现,从而对MPLS网络数据平面缺陷的进行检测及定位,及时通知入节点进行保护倒换以维护网络高可用性、降低运营成本。     

ASON中UNI信令的实现

本文研究了UNI提供的服务，UNI信令的传输和调用方式以及UNI地址空间等关键技术。最后基于GMPLS RSVP-TE扩展实现UNI信令，给出了各个节点的有限状态机。     

ASON中UNI信令的实现

本文研究了UNI提供的服务,UNI信令的传输和调用方式以及UNI地址空间等关键技术。最后基于GMPLS RSVP-TE扩展实现UNI信令,给出了各个节点的有限状态机。     

以太接入网OAM信息的传输机制

由于以太网成熟的技术和广泛的应用,以太网接入技术已经成为接入网技术中的最新发展趋势。主要介绍了以太接入网OAM信息的传输机制,详细分析了MAC层OAM和物理层OAM信息的传输方案。     

A connection control strategy for bursty sources in broadband packet networks

This paper proposes an admission strategy for connection-oriented services at the access node of a broadband integrated packet network based on asynchronous transfer mode. Based on an estimate of the probability of cell loss and in the absence of buffering, we determine the number of sources from different classes of bursty traffic which can be accepted. The parameters which are used to describe the traffic sources are average bit rate and peak bit rate. We will evaluate the cell loss estimate for homogeneous and heterogeneous cases. Furthermore, we will examine the variation of this estimate as the average to peak ratio changes. The estimate is an upper bound for the probability of cell loss. Based on this upper bound simple and robust allocation of resources to bursty sources can be developed. The proposed strategy can be implemented using simple computations or via a look-up table to determine admission or denial of an incoming call and therefore allocating the required capacity. The procedure results in efficient use of the bandwidth, ensuring the desired service quality for connection-oriented services and results in proactive control of network congestion.     

An efficient method for computing cell loss probability for heterogeneous bursty traffic in ATM networks

In this paper, we present an approximation for the probability of cell loss of heterogeneous bursty traffic in broadband integrated packet networks based on the asynchronous transfer mode. The sources considered here alternate between active and silent periods and are characterized by their peak and average transmission rates. The cell loss probability is obtained by considering only the number of active sources at a given time and computing the amount of traffic that exceeds the link capacity. Since the amount of buffered excess traffic is not considered in this computation, this approximation is actually an upper bound of the cell loss probability. The numerical efficiency of this bound enables it to be used as a measure based on which robust and simple resource allocation strategies can be developed for bursty sources. Comparison of this bound with the simulation results has shown that the bound is close to the actual loss probabilities especially for large burst lengths and high utilizations.     

ATM OAM信元工作原理及网络应用

在ATM网络的维护、管理中，OAM信元发挥了极为重要的作用。本文在简单介绍OAM信元功能的基础上，重点分析了F5信元的工作原理和工作方式。最后，结合笔者在工作中遇到的ATM／FR网络调试问题简述了OAM信元在网络中的实际应用。     

Asynchronous transfer mode (ATM) operation via satellite: Issues,challenges and resolutions

Key issues regarding the operation of the broadband integrated services digital network (BISDN) via satellite are presented herein. The specific issues, challenges, and their resolutions are detailed. In particular, the impact of error characteristics and propagation delay on the operation of BISDN via satellite is discussed. Solutions are presented for removing adverse effects and providing high-quality service to users of BISDN via satellite.     

Comparison of admission control schemes in ATM networks

Asynchronous transfer mode (ATM) offers an efficient means of carrying a wide spectrum of BISDN traffic provided that network congestion is prevented. Unfortunately, efficient congestion control is difficult to achieve in integrated broadband networks, owing to the wide range of traffic characteristics and quality of service (QOS) requirements. We have implemented a network simulator that allows us to evaluate many proposed admission control schemes using many different traffic models. We present the results of several simulation studies, including one study of the performance of the admission control schemes in the presence of traffic sources that exhibit long-term dependence.     

MPLS网络的OAM功能研究与实现

首先结合MPLS的协议参考模型阐述了操作与维护(OAM)在MPLS网络中的地位、作用;其次,结合协议Y.1710和Y.1711,对OAM的数据格式和OAM的机制进行了介绍;最后对综合业务交换机中OAM软件的实现模型、内部外部接口进行了说明,并对OAM软件的4个主要模块:维护控制模块、连通性管理模块、故障管理模块和性能管理模块的功能实现进行了详细地说明。