令牌环介质存取优先控制的实现及其排队模型

该文给出了一种实现令牌环优先介质存取控制的方法。建立了基于该方法令牌环的排队模型，并对其进行了数学解析和特征分析。     

基于μC/OS II的Modbus/TCP消息的类令牌环实时响应算法

Modbus/TCP工业以太网标准本身不保证实时性。设计一种带优先级的令牌环调度算法,实现了对高优先级Modbus/TCP消息的实时响应,并在该算法基础上扩展出加权令牌环调度算法和变权令牌环调度算法,能满足可定制、可更改的响应延时需求。最后,在基于μC/OS II+ARM7的平台上测试响应延时为1.15±0.15ms,优于目前大多数对Modbus/TCP的实时性改造成果,甚至达到了开放模式下Powerlink的实时水准。     

令牌环网络协议适配器研究与实现

本文给出了一种基于协议处理器ＳＣＣ８２５３０的令牌环网络协议，该协议支持优先级访问控制算法，并提供了环网可靠工作所必需的ＭＡＣ管理帧；还讨论了以ＶＬＳＩ Ｉｎｔｅ８０１８６作为通信处理器，ＳＣＣ８２５３０作为协议处理器的令牌环网络协议适配器ＪＹＴＲＡ的设计。该协议适配器具有体积小、可靠性高、响应速度快等特点。网络数据速率达１Ｍｂｉｔ／ｓ。     

走向末路的令牌环

令牌环(Token Ring)介质访问控制技术最早开始于1969年贝尔研究室的 Newhall 环网,最有影响的令牌环网是 IBM Token Ring。IEEE802.5标准是在 IBM TokenRing 协议基础上发展和形成的。令牌环曾以其环状结构、信令分明、不易形成网络冲突而获用户青睐。但目前已很少有新的用户在建网时考虑采用令牌环技术了。     

价格更低 性能更好——IBM推出自动侦听高速令牌杯网卡

IBM日前推出了一种新型的自动侦听高速令牌环网卡——支持三种传输速度(100Mbps/16Mbps/4Mbps)的PCI令牌环网卡,它是IBM首次推出的高速令牌环解决方案。同时推出的还有两个PCI令牌环网卡的第三代更新产品——16/4 PCI令牌环网卡(16/4指数据传输速率为16Mbps/4Mbps)和带网络唤醒功能的16/4 PCI令牌环网卡。这些产品具备了最新的网络连接性能和很好的可管理特性,适用于服务器和台式机网络环境。     

一种适用于自组网的多信道轮询多址MAC协议

本文针对节点具有多个可用信道的自组网,提出了一种基于令牌环的多信道轮询多址MAC协议,协议在控制信道上采用令牌轮询接入方式来实现节点公平接入信道,通过令牌的传递预约数据信道来实现动态按需分配信道的数据传输,并对该协议进行了性能分析。     

壁合为珠联 Fore转售IBM公司交换机

1997年12月24日,FORE系统公司推出了TS-2800令牌环接入交换机。该产品是与IBM公司达成协议的结果,协议规定FORE系统公司采用其自己的TS-2800令牌环接入交换机品牌和所有销售渠道,对IBM公司的8270 Nways LAN交换     

令牌环的“强心计”

令牌环依靠快速100M产品得到了发展。     

多机系统中的总线仲裁技术

讨论了多机系统中的总线仲裁并行、串行、查询、令牌环等方法，并给出了它们在实际的同步系统中应用时的特殊电路。     

令牌总线令牌环的β性能分析模型

本文利用位长度因素概念和系统分解的方法,建立了令牌总线(IEEE802.4)、准广播式令牌环(IEEE 802.5)、顺序流式令牌环的β性能分析模型。它以验前随机分布的结点连同为前提,研究同一组结点上采用不同网络结构时的吞吐性能问题,描述了数据吞吐能力与网络结构、数据结构之间的关系,即可用于定性分析,也可用于一定条件下的定量分析,还具有可比性。     

Real-time fault tolerant operation of the 802.5 token ring

Scheduling a hard real time application on a token ring requires that the delays to capture the token be known. Previous studies considered only a small subset of the token ring mechanisms in schedulability analyses. In this paper, we study the influence of three types of faults on the time to capture the token. These are token losses, failures of the active monitor and cable faults. We also show the influence of the stack mechanism on the delay to capture the token. The paper ends with an evaluation of these delays in various ring configurations in which the transmission speed, token hold time and ring latency are variables. We conclude that the token ring may be very difficult to schedule for hard real time applications because we do not know if other mechanisms or combinations of phenomena can introduce additional delays that make the operation of the ring unpredictable in the present state of knowledge.     

H-R网络安全系统结构

文章首先分析了等级式+环形体系结构的特点，并在此基础上提出分布式安全体系结构方案：H-R网络安全系统结构。通过使用等级式结构，保证整个体系良好的可扩展性；通过使用安全令牌环协议(运行在环型结构中)，提高体系结构的健壮性，并简单介绍了安全令牌环协议的实现。最后对该体系结构进行了分析。     

Simple token ring local area network

The implementation of a simple token ring system is described. A token ring is a form of local area network in which hosts must capture the token, a unique bit pattern, to use the communications medium. Many existing token ring implementations designate a separate host as a monitor station for the ring. Thus ring initialization and recovery are centralized, so it the monitor is down the ring becomes unusable.Our aim was to build a simple cheap token ring which would have advantages over an Ethernet-style local area network in terms of guaranteed access time upper bounds. We also attempted to decentralize initialization and recovery by giving each host the ability to initialize and repair the ring.     

RMP: fault-tolerant group communication

Based on a logical token ring, this communication protocol ensures total message ordering and atomic delivery, so all group members maintain an identical view of ordered events. RMP (Reliable Multicast Protocol) is an efficient multicast protocol for general distributed applications based on the logical token ring approach. The novelty of RMP is that it simultaneously multicasts an ordered message and implicitly rotates the token position on the ring. There is no token transfer message in the normal multicast. For message atomicity, our protocol minimizes control messages and communication costs while incurring a relatively short delay. In contrast to other token algorithms, RMP does not risk losing the token when the token site fails. Without requiring extra overhead, our approach guarantees total ordering of messages and message atomicity-either every member receives a message, or none do     

令牌多环网性能—可靠性综合评价

网络的性能与可靠性已分别得到广泛的研究,然而,怎样分析具有容错机制的环网的性能仍属有待开拓的研究领域,本文提出了一种分析具有自修复机制的多环网络系统的方法,并给出了报文传输时间分布的拉氏变换式,平均等待时间及平均队列长度公式,分析结果可用于评估故障与修复过程对实时令牌环网的实时响应特性的影响,对基于LAN的分布式实时系统设计具有指导意义。     

基于令牌的ARCNET故障侦听与解码原理及实现

基于令牌传输协议ANSI/ATA878．1及ARCNET网络数据报文的编码原则，提出了直接截获传输介质信号流，解码复现信息帧的解码原理及其在实际工程项目中的具体实现。     

Performance evaluation of client-server systems

A client-server system is a distributed system where a server station receives requests from its client stations, processes the requests and returns replies to the requesting stations. The authors consider client-server systems in which a set of workstations access a file server over a local area network. The systems are modelled by a class of stochastic Petri nets. The mean response time, the throughput and the parametric sensitivities are evaluated for a client-server system based on token ring network and a system based on CSMA/CD network. These models are different from the prevalent performance models of token ring or CSMA/CD network systems because of the message interdependencies introduced by the clients-server structure. An approximate analytic-numeric method rather than simulation is used to solve the models. The solution method and the accuracy of approximation are also discussed