基于Web和SNMP的网络用户管理系统

现有的网络管理系统对于园区网中的终端用户缺乏有效的管理手段,满足不了当前园区网用户管理的需要。将Web技术与SNMP网络管理技术相结合,提出了一种基于B/S结构的网络管理模式,并采用ASP.net MVC3框架设计和实现了一个基于SNMP协议的Web网络用户管理系统,在Web平台上将设备管理与用户管理统一结合,通过软硬结合加强对网络用户的管理,减轻网络管理员的负担。     

无线ATM网介质访问控制协议的研究

近年来无线ATM网络得到广泛研究,扩展ATM网络的宽带业务至无线环境面临许多方面的问题。介质访问控制(MAC)方法是无线ATM网的关键技术之一。MAC层协议的好坏直接影响系统性能和移动终端的复杂性。文中综合分析目前已有的无线ATM介质访问控制协议及方法,指出设计无线ATM网MAC层协议的三条原则,提出下一步研究方向。     

基于SDH技术UNI适配器的设计与实现

SDH网络接口适配器是用户与ATM网络进行交互所需要的一种网络接口设备。文章首先就ATM用户网络接口适配器的相关协议、系统硬件结构及功能的实现进行了较为详细的讨论。然后遵循33MHz、32位PCI总线协议规范、ATM论坛和ITU-T制定的协议规范,设计实现了基于SDH技术、支持155Mbps数据传输率的UNI适配器,并给出了PM5350 S/UNI-ULTRA ATM 适配器接口的电路图。     

ATM网络技术的标准化,服务及在局域环境中的应用

ATM网络技术的标准化对于加速AlM网络技术的实现、保证AIM网络产品的开放性、从而保证和增强ATM网络服务对终端用户的价值意义重大。ATM网络技术的标准主要主ITU－T(国际电信     

以用户为中心的可信终端身份管理模型

针对终端用户身份管理难题和现有的身份管理技术的不足,为了满足终端用户在任何情况下访问网络资源的客观需求,文章提出了以用户为中心的可信终端域内、跨域和开放网络环境下的身份管理系统模型,在此基础上设计了包括终端用户身份安全保护机制、身份管理流程、终端用户身份管理协议的终端用户身份安全保护方案,对协议进行了安全性分析和形式化分析,并与其他身份管理模型的安全性进行了比较,结果表明该模型能够安全地管理用户身份和实现各种环境下的访问控制。     

一种比较研究:宽带社区接入技术的多服务提供

今天,宽带社区接入基础设施仍然是下一代网络的主要研究领域之一.除了流行的非对称数字用户环路、光纤同轴混合网和ATM无源光网络,学术界和工业界正日益表现出对于以太网技术应用于宽带社区接入网的巨大关注.试图调查通常的宽带社区接入技术的本质区别,给出全面的理解.综述了通常的宽带社区接入技术,基于复用方法和传输技术发布了新出现的基于以太网技术的社区接入网和非对称数字用户环路、光纤同轴混合网和ATM无源光网络的比较研究.这个比较研究深入地讨论了宽带社区接入技术网络结构、服务模型、通信量模型和服务质量提供.比较研究将有益于将来的宽带社区接入基础设施的研究与实现.     

新桥架起MPOA桥——连接ATM理想与现实

ATM的高速、可伸缩性、支持QoS的理想在向我们走来,但面对我们现有的以太网、令牌网和IP网络的基础架构的现实,我们需要的是一个具体的实现机制,将ATM集成到现有的多协议网络环境中。加拿大新桥网络公司所倡导的MPOA就是这样的一个解决方案。日前,该公司在天津举行研讨会,全面介绍MPOA(Multi-Protocol Over ATM)技术以及实现该技术的VIVID(VIdeo、     

ATM网络技术及应用

本文摘要介绍了ATM技术的基本原理和ATM与传统网络的互连技术，如局域网仿真。ATM上的国际协议IP、多协议MPOA和ATM上的IP交换机等。每种技术均有其优点和不足，选用何种技术完全取决于用户的应用需求。ATM技术可作为支持多媒体应用和服务器访问平台以及主干网络技术的最佳选择。     

Eastnet的设计与实现

Eastnet是一个总线型局部网络。该网采用应答式以太网(Acknowledging Ethernet)原理,向用户提供面向低级进程间通讯机制的服务原语,由这些原语,用户可以编制更高层次的通讯协议及高层应用软件。本文首先介绍Eastnet的结构,接着主要讨论Eastnet链路层及接口层、应用软件设计等问题。     

ATM网络的局域网仿真技术

本文讨论了ATM网络上局域网仿真的模型以及局域网仿真相关的多协议转换服务组件的功能．ATM局域网仿真技术使用户既能利用ATM的高速数据链路，又能保护现有的软硬件投资，并简化了网络管理工作量。     

无线网络中实现ATM的关键技术

无线ATM是异步转移模式(ATM)技术和移动通信技术发展的产物。ATM传输和交换以宽带、低误码率和高传输速率的传输介质为前提,可以提供多媒体服务和广泛的信息接入。而无线信道的传输特点是带宽受限、信道传输质量差和传输误码率高。文中首先介绍无线ATM的一般概念,其次说明在无线网络中实现ATM技术的关键问题及其解决方法,最后介绍无线ATM的网络协议。     

基于MPLS的IP-QoS机制研究

多协议标签交换（MPLS）网络层协议结合了异步交换模式（ATM）的交换技术和IP协议的路由技术,被认为是未来网络的关键协议,同时可被应用于IP网络提供服务质量保障IP-QoS和构建虚拟网.在介绍了综合服务模型IntServ和差分服务模型DiffServ两种服务模型工作原理和网络结构的基础上,重点对IP-QoS在MPLS域的实现机制及其实现的优势做研究了,最后对基于MPLS的IP-QoS应用做了分析.     

ATM校园主干网下子网的互连方案

在ＡＴＭ校园主干网下如何使用ＡＴＭ技术把传统的以太子网互连起来，这是本文讨论的中心议题。在这种前提下，阐述了使用ＡＴＭ的三种标准协议来分别解决以太子网互连的几种方案，并进行了分析和比较。重点阐述了使用ＭＰＯＡ解决以太子网互连的技术。     

Overview of ATM networks: functions and procedures

The purpose of this paper is to present an overview of the ATM technique. The basic principles of the ATM transfer technique, the B-ISDN layered protocol reference model, as well as the architecture and the main functions of the ATM network, are described in this tutorial. In particular, we present the main characteristics of the ATM technique, the structure of the ATM cell, the functions which deal with the protection from errored cells (HEC procedure) and the identification of the boundaries of the ATM cells (cell delineation and scrambling). The VP/VC concept is explained in detail, and the main principles and functions of the three lowest layers (Physical, ATM and Adaptation) of the B-ISDN layered protocol reference model are surveyed. The issue of Quality of Service parameters in ATM networks is reviewed, and the problem of the allocation of the network resources in response to user demands, as well as the problems of congestion control, Usage Parameter Control (UPC) and traffic modelling in ATM networks, are assessed. Finally, we present ‘possible’ sets of traffic characterization parameters, and show how possible B-ISDN sources can be modelled according to the basic on-off ATM traffic source model.     

基于校园网组建的ATM技术应用研究

ATM技术全称为异步传输技术,在当今信息多样的网络社会中逐渐兴盛起来。ATM技术数据传输速度较高,能够同时传输多元化信息。对于校园网这种类型的局域网而言,通常要求所组建的局域网满足多样化用户的信息传输。由于校园内人数众多,数据传输量大,因而需要有高速传输的网络。ATM技术给好能满足校园网的基本需求,因而大多数校园网的建设采用ATM技术。     

在ATM网络上MPLS的实现

多协议标记交换技术(MPLS)能在主干网上大大提高IP转发性能，并提供服务分类(CoS)及服务质量保证(QoS)。MPLS在现有的主干ATM网上可提供高性能的IP服务。该文主要介绍了MPLS技术，并讨论了在ATM网上实现MPLS所必须解决的一些关健技术。     

Performance analysis of fast reservation protocols in ATM networks

In Asynchronous Transfer Mode (ATM) networks, VP/VC establishment and bandwidth reservation can be separately performed. Fast Reservation Protocol (FRP), a recently proposed protocol, utilizes this unique feature of the ATM technology to accomplish an efficient use of bandwidth. In FRP, a protocol data unit is called a burst, and a source requests the bandwidth reservation for each burst transmission on the established connection. In this paper, we provide an exact analysis for a class of FRP to obtain the burst delay distribution. Another feature of ATM is that the transmission rate can be set freely if it is admitted by the network. In our modeling, this feature is also incorporated in such a way that the requested bandwidth is reduced if the first attempt to reserve bandwidth is rejected by the network. Through numerical examples, appropriate values of control parameters such as the requested transmission rates are examined to show an effectiveness of FRP. The influences of the propagation delay and overhead due to control cells are also investigated by introducing an approximate technique.     

Mobility management and control in intelligent wireless ATM networks

This paper shows how the Asynchronous Transfer Mode (ATM) signaling and the Intelligent Network (IN) concept can be exploited to support mobility in an ATM-based network with wireless access parts and mobile users. The proposed architecture exploits the enhanced service control processing features offered by the IN technology to support location management. The access signaling protocol structure is based on the principles of separation between call and bearer channel control, employed in fixed broadband access networks. The design objective is to minimize the changes required to the wired network signaling, by taking advantage of the well-developed capability sets. This allows the easy introduction of the wireless ATM technology (W-ATM) into the real world. It is shown that the proposed signaling protocol model provides cost-effective implementations without degrading the agreed Quality of Service (QoS) and the system's performance. A comparative signaling performance evaluation is carried-out to demonstrate the impact of the proposed signaling protocol architecture onto various performance measures and to quantify the relative gains. The obtained results can be used for network design purposes in a large-scale private installation supporting many users. The signaling protocol architecture aims for private W-ATM networks, but can be readily extended to fulfill the signaling requirements of public environment broadband wireless systems.     

The great networking correction: frames reaffirmed

The paper considers how frame-based network technologies of local area networks are retaking their role as the primary campus technology, providing connections from desktop through backbone. This development comes at the expense of cell-based ATM, which was widely viewed as the inevitable, and highly desirable, next wave in transport technologies. ATM had been expected to supplant LAN-based transport and allow data, voice, and video to converge on a single, multi-transmission rate network. That ATM will become the dominant campus transport technology, however, seems less and less likely. Technical benefits once unique to ATM have become fewer with recent advances in both Ethernet and token ring technologies. As a result, monetary investment in ATM technology has fallen off sharply. ATM technology will likely become less visible as fewer servers and high-end workstations use it for direct connections. It will, of course, continue to provide robust switch-to-switch connections in some campus backbones. It may thrive in the carrier space, where its scalability, support for multiple traffic types, and circuit-based paradigm can be put to good use     

基于网络处理器的ATM网络流量监测分析

针对异步传输模式网络，提出了流量监测指标。基于C-5网络处理器，设计并实现了ATM网络流量监测分析系统。该系统能够执行ATM网络的VPI/VCI利用率测量、信元重组及上层协议分析等功能。实验数据表明，系统在监测OC-3/OC-12链路时丢包率小于0.001%，满足速率及精度的要求，能够实现线速测量。