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1.
结合以ATM为基础的无源光网络(APON)的G.983建议,提出了一个能同时实现话音业务,一般ATM业务和IP业务接入的媒质接入控制(MAC)协议,通过建模仿真,分析了该协议的时延和时延变化性能。  相似文献   

2.
结合以ATM为基础的无源光网络的G.983建议,提出了一个基于预留的 接入控制协议,通过建模仿真,分析了此协议在多种业务流组合下的时延和时延变化性能,并提出了一种硬件实现方案。  相似文献   

3.
加速无限输出缓冲ATM交换机性能分析   总被引:2,自引:0,他引:2  
讨论了带有内部加速的无限输出缓冲ATM交换机,提出了一种计算信元丢失率及平均时延的分析模型,并进行了计算机仿真。仿真结果表明,该分析模型是十分准确的。  相似文献   

4.
讨论了带有内部加速的有限输出缓冲ATM交换机,提出了一种计算信息元丢失率及平均时延的分析模型,并进行了计算机仿真,仿真结构表明,该分析模型是十分准确的。  相似文献   

5.
研究了一种基于可编程逻辑阵列(FPGA)为核心的异步传输模式(ATM)传输技术的设计。用FPGA实现ATM网络用户层、ATM适配层、ATM层三个层次协议,与ATM物理层芯片对接,形成同步光纤网络(SONETSTS-3)帧结构,完成ATM全双工通信,所需硬件资源少、功耗低、处理速度快,纯数据速率可达140Mbps。  相似文献   

6.
应用于Ad Hoc网络的时延敏感自适应路由协议   总被引:3,自引:0,他引:3  
针对Ad Hoc网络中实时业务对网络平均时延的要求,提出了一种应用于Ad Hoc网络的新型路由协议——时延敏感的自适应路由协议。该协议在保持“最少跳数”的最佳路由条件下,增加了“平均最短时延”的约束条件,从而不仅可以为实时业务(即时延敏感的业务)提供可靠的路由,同时还能根据网络节点当前的业务流量,动态地选择最佳路径,降低网络的平均时延。这是一种新型的有QoS保证的路由协议。仿真结果表明,该协议的确可以有效地改善网络的性能。  相似文献   

7.
通过在PON段层上用ATM仿真层来代替原来的ATM层,提出了一种VP级的MAC方案,本方案不仅能够灵活动态地分配用户上行接入的带宽,还具有统一的业务流管理,高带宽利用率和低信元时延等优点。  相似文献   

8.
仿真分析了光突发交换(OBS)网络在接入TCP和UDP协议以及不同输入流量特性业务时的性能,以及端到端延迟和组装时延对TCP和UDP协议的数据发送速率的影响。结果表明:在正常负载下,OBS边缘节点对UDP协议的支持能力高于对TCP协议的支持能力;而无论在TCP还是UDP协议下,边缘节点对恒定比特率(CBR)流量的支持都要好于对指数分布(EXP)流量的支持;在TCP协议下,数据发送速率随端到端延迟和组装时延的增大而降低;而UDP协议下,数据发送速率不受延迟和组装时延的影响。  相似文献   

9.
一种支持多跳无线网QoS业务的MAC层接入协议   总被引:1,自引:0,他引:1  
周滨  郭伟  任智 《中国测试技术》2006,32(2):100-103
提供一定的服务质量保证(QoS)是多跳无线网络研究中的热点和难点,本文基于TDMA/FDMA机制提出了一种支持多信道多跳无线网络话音级QoS业务的MAC层接入协议RA/SRN。该协议以RBRP协议思想为基础,针对无线信道中隐藏、暴露终端造成的信道利用率降低和分组冲突问题进行改进设计,减小了信道冲突概率,提高了信道利用率,降低了信道接入时延,为网络层QoS路由协议提供了良好的支持。  相似文献   

10.
提出了一种新的采用Kohonen神经网络的ATM接入控制方法,它避免了在BP神经网络中存在的大量训练数据和精确的学习训练之间的矛盾,不仅学习收敛快,而且数值结果表明在保证业务质量的前提下获得了相当高的信道利用率。  相似文献   

11.
The future development of air traffic management (ATM), set by the ATM 2000+ Strategy, involves a structural revision of ATM processes, a new ATM concept and a system approach for the ATM network. This requires ATM services to go through significant structural, operational and cultural changes that will contribute towards the ATM 2000+ Strategy. Moreover, from a technology viewpoint, future ATM services will employ new systems forming the emergent ATM architecture underlying and supporting the European Commission's Single European Sky Initiative. Introducing safety relevant systems in ATM contexts requires us to understand the risk involved in order to mitigate the impact of possible failures. This paper is concerned with some limitations of safety analysis with respect to operational aspects of introducing new systems (functionalities).  相似文献   

12.
Asynchronous transfer mode (ATM) traffic emulators have been designed for demonstrating the performance of various protocols and services in ATM networks under user-defined traffic conditions. Analytical tools and traffic measurements show that specific traffic conditions can be emulated by using the superposition of various stochastic processes. This paper presents a generic method for implementing stochastic processes using dedicated hardware and describes how this method has been used for implementing a real-time traffic emulator of ATM virtual channels.  相似文献   

13.
The asynchronous transfer mode (ATM) is a promising technique for broadband switching that is capable of supporting high-bit-rate multimedia services. Progress in all-optical parallel processing shows that photonics may be used in the future in full-functionality ATM switching nodes. All-optical switching fabrics and buffers have already been demonstrated. Fewer studies have been dedicated to ATM header-processing functions. As an example of photonic header processing, the implementation of a header-error control (HEC) subsystem by means of an optical circuit is investigated. Although traditional electronic decoders perform HEC in a serial mode, the architecture chosen for the optical HEC subsystem is based on parallelism, and an appropriate parallel-decoding algorithm was used in designing it.  相似文献   

14.
Quantified risk and safety assessments are now required for safety cases for European air traffic management (ATM) services. Since ATM is highly human-dependent for its safety, this suggests a need for formal human reliability assessment (HRA), as carried out in other industries such as nuclear power. Since the fundamental aspect of HRA is human error data, in the form of human error probabilities (HEPs), it was decided to take a first step towards development of an ATM HRA approach by deriving some HEPs in an ATM context.This paper reports a study, which collected HEPs via analysing the results of a real-time simulation involving air traffic controllers (ATCOs) and pilots, with a focus on communication errors. This study did indeed derive HEPs that were found to be concordant with other known communication human error data. This is a first step, and shows promise for HRA in ATM, since HEPs have been derived which could be used in safety assessments, although these HEPs are for only one (albeit critical) aspect of ATCOs’ tasks (communications). The paper discusses options and potential ways forward for the development of a full HRA capability in ATM.  相似文献   

15.
基于MDR-TDMA(Multi-service Dynamic Reservation-TDMA)的无线ATM多址接入控制协议包括两个主要的过程,即请求报文的信息时隙的分配过程,对于前者,通过基于帧的自适应伪贝叶斯ALOHA算法,在保证请求报文最优吞吐率的条件下,实现了不同优先级的请求报文接入。对于后者,着重分析了以视频会议为模型的VBR业务的带宽分配,提出了一种新的带宽分配方法-Minmax算法,并将它的仿真结果与线性比例算法进行比较。  相似文献   

16.
In the last decades, the air traffic system has been changing to adapt itself to new social demands, mainly the safe growth of worldwide traffic capacity. Those changes are ruled by the Communication, Navigation, Surveillance/Air Traffic Management (CNS/ATM) paradigm , based on digital communication technologies (mainly satellites) as a way of improving communication, surveillance, navigation and air traffic management services. However, CNS/ATM poses new challenges and needs, mainly related to the safety assessment process. In face of these new challenges, and considering the main characteristics of the CNS/ATM, a methodology is proposed at this work by combining “absolute” and “relative” safety assessment methods adopted by the International Civil Aviation Organization (ICAO) in ICAO Doc.9689 [14], using Fluid Stochastic Petri Nets (FSPN) as the modeling formalism, and compares the safety metrics estimated from the simulation of both the proposed (in analysis) and the legacy system models. To demonstrate its usefulness, the proposed methodology was applied to the “Automatic Dependent Surveillance-Broadcasting” (ADS-B) based air traffic control system. As conclusions, the proposed methodology assured to assess CNS/ATM system safety properties, in which FSPN formalism provides important modeling capabilities, and discrete event simulation allowing the estimation of the desired safety metric.  相似文献   

17.
陈子铨  杜选民 《声学技术》2010,29(6):583-586
为了适应声纳系统一体化的发展需求,提出了一种基于ATM(Asynchronous Transfer Mode)传输技术的网络化基元域数据传输系统。讨论了ATM技术在声纳数据实时采集与传输中的应用;给出了ATM技术传输效率与数据帧大小的关系;阐述了ATM数据传输节点、ATM交换机和ATM数据传输系统的设计。该系统已成功应用于某声纳中,为该声纳提供了一个总带宽为622Mbps的水声数据网络,并为多声纳间基元域数据共享提供了有效途径。  相似文献   

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