Implementation of Embedded Ethernet Based on Hardware Protocol Stack in Substation Automation System

Embedded Ethernet technology has been utilized increasingly widely as the communication mode in the substation automation system(SAS).This paper introduces the current applying situation about embedded Ethernet in SAS First.After analyzing the protocol levels used in SAS based on embedded Ethernet and the differences between the TCP and UDP,UDP/IP is selected as the communication protocol between the station-level and bay-level devices for its real-time characteristic.Then a new kind of implementation of the embedded Ethernet is presented based on hardware protocol stack.The designed scheme can be implemented easily,reduce cost significantly and shorten developing cycle.

Self-organization of Reconfigurable Protocol Stack for Networked Control Systems

In networked control systems （NCS）,the control performance depends on not only the control algorithm but also the communication protocol stack.The performance degradation introduced by the heterogeneous and dynamic communication environment has intensified the need for the reconfigurable protocol stack.In this paper,a novel architecture for the reconfigurable protocol stack is proposed,which is a unified specification of the protocol components and service interfaces supporting both static and dynamic reconfiguration for existing industrial communication standards.Within the architecture,a triple-level self-organization structure is designed to manage the dynamic reconfiguration procedure based on information exchanges inside and outside the protocol stack.Especially,the protocol stack can be self-adaptive to various environment and system requirements through the reconfiguration of working mode,routing and scheduling table.Finally,the study on the protocol of dynamic address management is conducted for the system of controller area network （CAN）.The results show the efficiency of our self-organizing architecture for the implementation of a reconfigurable protocol stack.

基于Ethernet的嵌入式测控系统的设计

在分析工业控制网络发展趋势、嵌入式以太网接入Internet网络数据传输需要的协议的基础上,针对现场总线通信方式的不足,设计了一个基于Ethernet的嵌入式测控系统。文章阐述了系统的设计方案,在硬件电路设计上,重点介绍了测控系统数据采集节点设计和以太网通信接口电路的设计;在软件系统设计上,提出测控终端软件设计方案,并实现了基于TCP/IP协议栈的网络通信设计。实际使用表明,该系统运行灵活、可靠、稳定,可直接使用企业内部的Intranet信息网,也可直接接入现行的公共Internet网络。

CAN总线与Ethernet互联网关的设计

在对CAN协议及TCP/IP协议栈进行深入研究的基础上,设计了以太网与CAN总线互联网关,该设计可以实现基于TCP/IP协议的计算机网络设备与基于CAN总线协议的底层现场网络互联。通过Visual C++6.0编写了网关上的程序使用了MSComm和WinSock控件提供串口通信和TCP/IP通信功能,通过数据包发送和接收实验表明Can-Ethernet网关设计的有效性。

A Dynamic Protocol Stack Structure for Diversified QoS Requirements in Ad Hoc Network

A dynamic protocol stack(DPS) for ad hoc networks, together with a protocol stack construction scheme that is modeled as a multiconstrained knapsack problem is proposed. Compared to the traditional static protocol stack, DPS operates in a dynamic and adaptive manner and is scalable to network condition changes. In addition, a protocol construction algorithm is proposed to dynamically construct of the protocol stack each network node. Simulation results show that, the processing and forwarding performance of our scheme is close to 1 Gb/s, and the performance of our algorithm is close to that of the classical algorithms with much lower complexity.

A NOVEL MARKOV ANALYTICAL MODEL FOR THE TCP/AQM SYSTEMS

A novel closed-loop feedback TCP/AQM(Transfer Control Protocol/Active Queue Management) model is proposed in this paper using a discrete-time Markov chain,and a way to calculate the equilibrium distribution of this model is given.In the model,system time is divided into time slots,the bottleneck router queue model and TCP window size model in each slot are analyzed.Finally,by combining adjacent slots,an integrated TCP/AQM analytical model is developed.By this model,the average values of packets dropping ratio and queue length in the router and TCP sending rate can be estimated,hence,this model could be a useful tool for the analysis of AQMs and support the development of new AQM schemes theoretically.The proposed TCP/AQM model is extended to a TCP-UDP(Control User Datagram Protocol)/AQM model,to analyze the TCP/AQM system performance when UDP flows exist.By implementing this model on Matlab,we compare its solutions to NS2 simulated solutions,then the validity of the model to analyze the closed-loop feedback TCP/RED(Random Early Detection) system is verified.

An efficient cross-layer buffer management optimization scheme for 5G protocol stack

It is extremely challenging for the 5G User Equipment(UE)to meet the requirement of low-latency data transmission with higher achievable data rates.And user plane processing of 5G protocol stack(PS)is one of the dominating components for end-to-end data transmission in the network system.In this paper,a cross-layer buffer management scheme(CLBM)is proposed.CLBM adopts a zero-copy technique for protocol data unit(PDU)processing between protocol layers and allows to improve the memory operation efficiency significantly with reduced processing latency and CPU usage.Moreover,the PS performance profiling(PSperf)tool,a general evaluation framework for the performance measurement and analysis of PS,is implemented based on the OpenAirInterface(OAI)5G platform.The evaluation result shows that compared with the PS of OAI the CLBM strategy reduces the CPU usage of RLC,PDCP,and MAC layer processing significantly up to 20.6%,63.4%,and 38.8%,respectively.In result,the processing delay of the whole user plane of PS also has been reduced distinctly at various offered traffic load.

基于Windows套接字的Ethercat主站协议栈设计与实现

针对Ethercat主站需要专用硬件或者特殊网卡驱动的问题,提出了一种在windows平台上利用套接字实现Ethercat主站的方法。首先对协议栈进行模块化设计;然后分析了Ethercat协议在UDP/IP协议上的报文规范,并实现了主站对从站的读写;在此基础上设计了协议栈自动配置从站的方法;最后采用wireshark软件抓取通信数据包,实验结果表明:设计的协议栈能够实现对从站的配置及数据交换,验证了协议栈的正确性。

A new protocol for concurrently allocating licensed spectrum to underlay cognitive users

Cognitive radio technology makes efficient use of the valuable radio frequency spectrum in a non-interfering manner to solve the problem of spectrum scarcity. This paper aims to design a scheme for the concurrent use of licensed frequencies by Underlay Cognitive Users （UCUs）. We develop a new receiver-initiated Medium Access Control （MAC） protocol to facilitate the selections of alternative reliable carrier frequencies. A circuit is designed to establish reliable carrier selections based on the Received Signal Strength Indicator （RSSI） at the receiving end. Based on both packet-level simulations and various performance parameters, a comparison is carried out among conventional techniques, including the Multiple Access with Collision Avoidance （MACA） and MACA by invitation（MACA-BI） techniques, and our scheme. The simulated results demonstrate that when conventional techniques are used, the system overhead time increases from 0.5 s on the first attempt to 16.5 s on the sixth attempt. In the proposed scheme under the same failure condition, overhead time varies from 0.5 s to 2 s. This improvement is due to the complete elimination of the exponential waiting time that occurs during failed transmissions. An average efficiency of 60% is achieved with our scheme while only 43% and 34% average efficiencies are achieved with the MACA and MACA-BI techniques, respectively. The throughput performance of our scheme on the fourth attempt is 7 Mbps, whereas for the MACA and MACA-BI protocols, it is 1.9 Mbps and 2.2 Mbps respectively.

基于F-Stack的高性能ICN网关设计与实现

部署信息中心网络(ICN)协议转换网关是实现ICN与现有IP网络兼容演进的一种方式。为了提升网关在数据流量的处理与转发方面的效率,避免网关的数据处理瓶颈影响ICN提供的性能增益,本文提出一种基于F-Stack开发框架的高性能ICN网关设计方法。该网关系统利用DPDK用户态协议栈快速处理大量TCP连接与流量,并结合DPDK的共享内存与无锁环形队列机制实现进程间通信,不仅具备良好的性能,而且可以降低模块间的耦合性。实验结果表明,在8核CPU资源配置下,本文方法具有良好的性能优势:数据传输速率可达75%网卡线速,同时支持87万个以上的并发连接,且平均处理时延在45μs以下。

基于Z-Stack协议栈的WSN能量管理策略

在分析基于ZigBee协议的Z-Stack1.4.3协议栈基础上,实现无线传感器网络(WSN)数据的自动周期获取,通过设置协议栈中休眠条件,不仅能最大限度地降低功耗,而且可以保证网络的同步性。构建一个簇树结构的低功耗ZigBee网络,设计具有网络数据、拓扑显示等功能的监控管理系统。应用结果表明,该系统能在低功耗下稳定地工作,完成环境数据监测。

基于Z-Stack协议栈的无线温湿度采集系统

基于Z-Stack协议栈,以CC2530射频收发芯片和DHT22数字温湿度传感器为核心,采用Zig Bee无线通信技术设计实现了无线温湿度采集监测系统,并在IAR环境下采用上位机软件以GUI的方式在终端直观地显示温湿度变化情况.主要阐述了系统结构设计、温湿度数据采集流程和图形化界面监测实现.实验表明,该系统实现温湿度数据的采集不但实时有效、可扩展性良好,而且具有极高的可靠性和卓越的稳定性.

基于Z-Stack协议栈的船舶机舱环境监测系统设计

为提高船舶机舱的安全性,针对传统有线监测方式存在布线困难、成本高和扩展性差的缺点,设计了一套基于Z-Stack协议栈的监测系统。该系统综合了Zigbee无线网络自行愈合、组网灵活和超低功耗的优点,以CC2530射频模块为基础组成网络节点,由传感器节点把测得的温湿度值、CO_(2)浓度和空气流速等参数经路由器或直接传递到协调器,最终传至上位机监控界面来实时显示、记录数值。试验结果表明,该系统具有功耗低、稳定性高、可开发性强等特点,满足机舱里监测实时性和数据精度的要求,同时对提高船舶自动化水平具有一定的参考和借鉴意义。

基于Stacking模型融合的专变用户电费回收风险识别方法

针对当前电力公司面临的专变用户电费回收风险,提出一种基于Stacking模型融合的专变用户电费回收风险识别方法。对专变用户数据进行特征处理、特征构造与特征筛选,从样本分布和特征属性上优化模型的泛化性能;利用Stacking模型融合多个基学习器,构建专变用户电费回收风险识别模型。实验结果表明,相较于其他常用的分类算法,所提方法具有更优的精确率、召回率、P-R调和均值、AUC值以及模型泛化性能,对专变风险用户的识别率也更高。

基于Z-Stack的ZigBee协议栈组网过程研究

在ZigBee协议栈Z-Stack基础上,重点分析了Z-Stack协议栈的结构和组网类型,通过详细研究TI公司的Z-Stack协议栈核心的实现过程,从代码级别对ZigBee协议栈组网过程进行剖析和节点组网过程中的重要函数调用进行详细分析,对实际工程项目开发有一定的指导作用。

TCP Offload系统的设计与实现

网络带宽的迅速发展使主机协议处理开销成为系统整体性能的瓶颈。为了提高网络应用的性能、降低主机系统的资源占用,该文采用网卡子系统分担主机的网络包收发和TCP协议处理,设计实现了一个TCP offload系统,分析了一般TCP offload系统在性能和实施的困难,给出系统设计的基本原则,介绍了系统在通信接口、资源管理、事件管理和用户接口等方面的实现。系统测试结果表明,网卡能处理高速的网络应用,在一些情况下甚至达到线速。

基于Stacking与多特征融合的加密恶意流量检测

加密技术保护网络通信安全的同时,大量恶意软件也采用加密协议来隐藏其恶意行为。在现有基于机器学习的TLS加密恶意流量检测模型中,存在单模型检测算法对多粒度特征适用性差和混合流量检测误报率高的问题。提出基于Stacking策略和多特征融合的非解密TLS加密恶意流量检测方法。分析加密恶意流量特征多粒度的特点,提取流量的流特征、连接特征和TLS握手特征。对所提取的特征通过特征工程进行规约处理,从而减少计算开销。对规约处理后的3类特征分别建立随机森林、XGBoost和高斯朴素贝叶斯分类器模型学习隐藏在流量内部的规律。在此基础上,使用流指纹融合处理后的多维特征,利用Stacking策略组合3个分类器,构成DMMFC检测模型来识别网络中的TLS加密恶意流量。基于CTU-13公开数据集对构建的模型进行性能评估,实验结果表明,该方法在二分类实验上识别召回率高达99.93%,恶意流量检测的误报率低于0.10%,能够有效检测非解密的TLS加密恶意流量。

Z-STACK协议栈应用开发分析

Z-STACK协议栈可为基于开放式协议的应用开发提供强大的功能支持。为了理清协议栈的工作过程,文中在简要说明了Z-STACK协议栈的层次结构及任务调度流程的基础上,结合具体案例,剖析了基于Z-STACK协议栈的应用开发流程。

基于TI Z-STACK的智能小车调度系统设计

针对高职院校物联网应用技术专业实训问题,基于MCS-51及CC2430单片机、红外及超声波传感器,设计了一套基于TI Z-STACK协议栈的智能小车调度系统。分析了无线网的组建流程及软件实现方法。

适合酒店应用的Z-Stack协议的研究与实现

应用先进的信息化、智能化技术来改变现有的酒店管理和经营方式,可以有效地解决现有酒店管理效率低,人工成本高等问题,而这些技术的应用都需要高效、安全的网络来支撑。本文根据Z-Stack协议的特点,以及在酒店对所使用的无线网络的特殊性及要求,在原有Z-Stack协议的基础上设计了专门用于酒店自动化的ZStack协议。论文从网络结构、固定地址处理、安全与加密以及低功耗等几个方面对所设计的协议进行了阐述,最后给出了所设计的Z-Stack协议在酒店门锁管理系统中的一个具体应用。本文提出的专用于酒店管理的ZStack协议不仅数据传输可靠性高、安全性高,并且成本低、功耗低,能有效提高酒店的经济效益,提升酒店的服务水平。