Token ring network management: Change management

This article, which is the fifth in the series on Token Ring Network Management, will discuss selected aspects of Change Management that are relevant in today's Token Ring networking environment.     

Token ring network management: Configuration management

In this fourth article in the series on Token Ring Network Management we will discuss selected areas of relevance to today's Token Ring networking environment.     

Token ring network management: Problem management

Following the tutorial ‘Token Ring Network Management’ article in the previous issue of the International Journal of Network Management, this article takes us through some more detailed Problem Management scenarios.     

分布式无线令牌环接入技术在无线自组网中的应用研究

本文在无线令牌环协议(WTRP)的基础上,提出了一种在无线自组网中无竞争的分布式无线令牌环协议(DWTRP),仿真实验表明该协议的排队等待延迟和等待队列长度均比WTRP有很大降低,稳定性大大增强。     

浅谈令牌环网络的发展方向

文章论述了令牌环网络的发展方向。并分析介绍了各类交换技术的特点。     

Token Ring Network Management

This article on Token Ring network management describes general aspects of this important area and gives a brief introduction to the various disciplines, which will be covered in more detail in following articles.     

无线动态令牌协议及性能分析

 本文在无线令牌环协议(WTRP)的基础上,提出了一种无线动态令牌协议(WDTP),以解决其网络拓扑适应能力差和管理控制复杂的问题.本文首先介绍了WDTP协议的工作原理,然后详细阐述了令牌的动态传递算法、子网的建立过程和令牌的管理维护技术,对WDTP协议和WTRP协议的性能进行了分析比较,并通过模拟仿真比较了两种协议对网络拓扑结构的适应能力.仿真结果表明,WDTP具有良好的网络拓扑适应能力,并因此提高了频率资源的利用率.     

Migration Issues and Strategies for Token Ring

This article considers the problems caused by ever increasing traffic on Token Ring LANs. It shows how the new IEEE 802.5 standard for DTR addresses this problem, outlining scenarios and providing a migration strategy for evolving networks, using this new standard. © 1997 John Wiley & Sons, Ltd.     

A novel fault tolerant token ring network

Token Ring Networks have gained popularity due to their simplicity and ease of maintenance. However, the functioning of the entire network is dependent on the well being of an entity called “token”. The network ceases to function if the token is lost. There are algorithms suggested for improving the fault tolerant capabilities of the network with respect to the token.This paper proposes an algorithm to achieve fault tolerance. The algorithm is implemented on a simulated token ring network.     

Approximating dependability measures of computer networks: an FDDIcase study

An approximation technique is presented to evaluate the dependability of FDDI networks. This technique, based on the most likely paths to failure concept, is simple and practical. It may be applied easily to evaluate and compare the dependability of different FDDI network configurations. The effects of various network parameters on the network availability are examined. We conclude that, in order to guarantee high availability, an FDDI network backbone should be interconnected using dual-attachment concentrators. Furthermore, dual-homing configurations are required for high-availability paths between end stations and the backbone. For less stringent availability requirements, single-attachment concentrator trees with single attachment stations may suffice. We also discuss how the technique may be extended easily to more general heterogeneous networks including Token Ring and Ethernet     

移动Ad hoc网络轮询接入控制协议

该文对Ad hoc网络的MAC层协议进行了研究,通过对无线令牌环协议(WTRP)进行改进,提出了一种新的具有QoS保障的无竞争的分布式并行无线轮询访问协议(DPWPAP),并采用嵌入Markov链和概率母函数的分析方法,用限定服务规则进行了系统建模,在系统模型的基础上得到了系统的平均排队队长以及平均等待时间的解析结果.理论分析和仿真结果是一致的,表明该协议的排队等待延迟和平均等待队列长度均比WTRP有很大降低,稳定性大大增强,更加适用于对时延要求较高的业务.     

New standard helps multimedia get off the ground

The Institute of Electrical and Electronics Engineers began working on a transmission standard for multimedia networking almost a decade ago. Since the standard's recommendation in December 1994, it has taken little more than a year to capture the attention of manufacturers, vendors, resellers, systems integrators, and network users. The IEEE standard for multimedia in a local area network (LAN) is based on ISLAN-1GT, or isochronous Ethernet. Better known as isoEthernet, the standard incorporates an integrated services digital network phone system with LAN-based Ethernet for mixed data transmission. The IEEE standard, designated 802.9a for LANs and metropolitan area networks, is simply a physical layer standard-just like Ethernet 802.3/ISO 8802-3 and Token Ring 802.5-in that it defines the standard's media access control and physical layer     

Technology 1991: data communications

Significant developments during 1990 are examined, and future trends are delineated. Two major events were the rapid acceptance by end users of the 10BASE-T standard for Ethernet interconnections using unshielded twisted-pair wiring and the widespread acceptance of the fiber distributed data interface (FDDI) by corporate planners and MIS (management information system) people, as well as government planners, as the way to wire the corporate backbone. 1990 also saw commercialization begin of the FDDI interface by which data is transmitted on an optical-fiber network at 100 Mb/s rates. The development of twisted-pair wiring for Ethernet and FDDI will lead to integration of Ethernet. Token Ring, and FDDI local networks in one concentrator in one wiring closet, while the pace of growth of the LAN market continues to accelerate. The seven layers of the Open Systems Interconnection (OSI) protocol received a big boost last year from the US government, and it is likely to become the routine way of organizing data networks worldwide     

Field failure analysis on transmission data equipment due to lightning discharges

The telecommunication equipments suffer more damages, dues to lightning and power lines induction, than other type of appliances. The cause is that they have direct connections with wires or cables that are exposed to transients, and usually the affected components have direct connections with external lines, but sometimes the mechanism is more subtle and can affect circuits without contact with exposed connections.This paper treats about failures on data interfaces circuits induced by voltage transients on the earth protection wire. It is based on a study of modems failures connected to remotes data terminals through RS-232 interfaces. Other data interface could also be damaged by this mechanism of failure (RS-422, Ethernet, Token Ring, etc.).On this type of failure the failed circuits (drivers and receivers RS-232) are not located nearly the transient entry gate (telephone line and VAC inputs). They are in an interface between two equipments, and usually the only failed components are the drivers and receivers.     

传统局域网的QoS保障机制的分析与应用

分析比较了传统的局域网中以太网和令牌网的性能和QoS保障特性,说明令牌网的支持QoS的特点可用于多媒体通信网络和实时控制系统的协议设计,并阐明其算法在最新的AdHoc网络QoSMAC协议改进的作用,最后介绍了一种将以太网和令牌网不同特性网络的分层实现技术和综合互连的方案。     

成本管理发展趋势

成本管理是生产力发展的产物,随着经济的发展而逐渐深化。文章从成本管理发展的三个历史阶段分别阐述成本管理的发展特点和规律,以及我国的成本管理发展现状。通过传统成本管理与作业成本管理的对比分析,指出当前成本管理的主要形式和未来成本管理将随着信息化的发展可能形成的主流模式。     

Security Attack Safe Mobile and Cloud-based One-time Password Tokens Using Rubbing Encryption Algorithm

One-time Password (OTP) Token has become one of the main stream security products during the past few years. OTP Token can automatically generate a random password. It is especially popular to be used with the Two-factor Authentication (2FA) system. OTP Token has proliferated into many different form factors such as standalone token, PC, PDA, cellular phone and Cloud-based token. But most of the implementation has their short comings with high token cost, not easy to carry and high supporting or deployment cost. Certain implementations may also compromise the network security when the token is lost or stolen. Moreover, most of the tokens can be broken-in by Man-in-the-Middle Seed-tracing and Shoulder-surfing security attacks. To overcome such aforementioned issues, we propose a secure encryption algorithm – Rubbing Encryption Algorithm (REAL). We use REAL to implement a Mobile-based and a Cloud-based OTP Token as design examples. Both of them are of high security level, lower total token cost and can resist the aforementioned security attacks as well.     

Design and implementation of an RSVP-based quality of servicearchitecture for an integrated services Internet

The Internet Engineering Task Force (IETF) is currently in the process of overhauling the architecture of the Internet to meet new challenges and support new applications. One of the most important components of that venture is the enhancement of the Internet service model from a classless best effort service architecture to an integrated services architecture supporting a multitude of classes and types of services. This paper presents the design, implementation, and experiences with a protocol architecture for the integrated services Internet. It is based on the emerging standards for resource reservation in the Internet, namely, the RSVP protocol and the associated service specifications defined by the IETF. Our architecture represents a major functional enhancement to the traditional TCP/IP protocol stack. It is scalable in terms of performance and number of network sessions, and supports a wide variety of network interfaces ranging from legacy LAN interfaces, such as Token Ring and Ethernet, to high-speed ATM interfaces. The paper also describes the implementation of this architecture on the IBM AIX platform and our experiences with the system. We then present a performance analysis of the system which quantifies the overheads imposed by all components of the QoS support, such as traffic policing, traffic shaping, and buffer management     

浅谈企业的计划管理

随着企业外部经营环境日趋严峻,市场竞争愈演愈烈,计划管理作为企业经营管理的一项重要内容,在越来越多的企业管理当中得到运用。     

虚拟令牌传递串行通讯方式在控制系统中的应用

本文主要介绍了虚拟令牌传递方式在控制系统中的应用 ,重点介绍了虚拟环形网令牌传递方式控制数据传输的机制