嵌入式Internet中TCP／IP协议栈的研究与设计

目前大多数嵌入式设备是8位或16位的MCU,要将Internet与嵌入式设备进行结合,其主要困难在于,相对于8／16位低速处理器本身资源的限制,Internet的TCP／IP协议簇过于复杂,因此不可能实现完整的TCP／IP协议栈,必须根据实际需求进行精简。针对8位或16位的低档MCU接入Internet,采用MCU＋软件嵌入TCP／IP协议的方法加以实现。对嵌入式Internet中TCP／IP协议栈的实现进行了研究与分析,针对每一层的具体协议,提出了设计方法和精简方案。由于嵌入式设备自身资源的限制,使得在嵌入式Internet中TCP／IP协议栈的实现存在功能简单、安全性不高等问题。但是随着嵌入式硬件设备和Internet技术的不断发展,嵌入式TCP／IP协议栈的实现也将会越来越完善。     

嵌入式Internet技术及其实现方案

嵌入式Internet技术在各行业中应用日益广泛．文章介绍了嵌入式Internet技术的原理和几种实现方案。并讨论了嵌入式TCP/IP协议的原理及在嵌入式系统中实现TCP/IP的问题，最终提出了一种嵌入式网关的应用实例．实现了单片机通过以太网联接Internet的目的。     

嵌入式TCP／IP网络协议栈架构与效率研究

嵌入式Internet技术关键问题在于如何在MCU中实现TCP／IP通信协议。现有的嵌入式网络协议研究多数停留在对协议的实现和协议实现的软件优化上,很多研究在内存管理上研究TCP／IP协议存储管理、设计等方面做了一些分析和实验,目前几乎没有在系统架构层面,从硬件和软件协作处理角度横向、纵向地比较研究。本文从硬件执行速度。软件系统内部结构分析,实现并比较嵌入式TCP/IP在不同应用中实现的不同技术,最终提出嵌入式TCP／IP协议栈系统在工业控制系统上最优化的方案。     

嵌入式Internet应用研究

随着Internet技术的发展,嵌入式系统的Internet应用越来越多。嵌入式系统的Internet应用扩展了Internet的应用范围,从而形成了新的技术领域——嵌入式Internet。介绍了嵌入式Internet的概念,然后阐述了嵌入式Internet的研究内容(重点介绍了3种接入技术模型)以及当前所用实现嵌入式Internet的TCP/IP协议栈,最后讨论了嵌入式Internet的发展前景。     

Embedded Internet环境下TCP/IP协议簇的约简

基于 Em bedded Internet技术下 ,为了实现非 Internet设备信息的共享和访问 ,作者对 TCP/ IP协议簇进行系统的研究 ,提出在设备中嵌入 thin TCP/ IP协议栈并使其能够实现与网络的透明互联 .对 TCP/ IP协议簇进行尽最大可能的约简而不使其失去标准和相应的机制 ,从而可以利用 TCP/ IP协议在设备与 Internet之间建立通讯联系 ,真正把设备纳入到网络的管理范围 ,实现设备的网络化和智能化管理 .设备中嵌入 TCP/ IP协议的实现为工业生产自动化系统和智能家电的网络化和智能化管理提供可靠的技术支持     

基于Modbus TCP/IP通信的实现

进行基于Modbus协议和TCP/IP协议相结合的远程网络通信,采用了套接字和多线程技术,使得Modbus协议的信息可以在TCP/IP协议的Internet上传输,从而扩展了Modbus协议的应用,并用基于以太网的控制器和制冷机组设备组成的网络上实现了远程网络通信。     

嵌入式Internet体系结构研究

研究了目前嵌入式Internet技术的二种典型体系结构,在此基础上分析和研究了嵌入式TCP/IP协议栈的特点及其实现方法。     

单片机嵌入式Internet技术研究及系统开发①

实现MCS-51单片机嵌入式接入Internet技术。单片机通过ATL8019AS以太网控制器实现与Internet的交互。利用开源代码的TCP／IP协议栈uIP实现对底层设备的驱动,同时通过uIP协议的应用程序接口实现各种应用服务。给出了硬件设计图,编写了单片机主程序。应用此技术实现了一个城市中心停车监测系统。     

基于Internet的实时控制系统的传输协议

为了在Internet实现实时控制，需要开发基于Internet的实时控制系统的传输协议。提出了该协议的设计方案，完全符合TCP／IP协议标准，并且在运输层同时支持TCP协议和UDP协议。以该协议为基础，开发了基于Internet的实时控制系统实验平台，实验表明该协议能在Internet上进行远程控制。     

基于Web的嵌入式设备监控模型的设计与实现

研究并实现了一种基于Web技术的嵌入式没备监控模型，使管理者可以通过Internet利用Web浏览器完成对现场设备的远程访问、监控和维护等操作，实现了异构设备之间的跨平台互访。对TCP／IP协议进行约简，实现了一个thin TCP／IP协议栈，为嵌入式设备提供了网络接口，实现了与Internet的无缝连接。嵌入式没备网关将TCP／IP协议与嵌入式设备监控协议之间的格式进行转换，实现了远程用户对现场设备的透明访问，具有智能化和远程管理的特点。通过对该模型性能的测试，结果表明基于Web的远程监控方式可以满足监控任务的需要，而且能有效降低监控运行维护成本、提高运行维护效率，具有实际应用价值。     

网络通信协议的分析与实现

网络通信协议是网络通信的基础。TCP/IP协议族是应用最为广泛的一种网络通信协议,无论在局域网、广域网还是Internet,无论是Unix系统、Windows平台都支持TCP/IP协议,是计算机世界的一个通用"语言"。讨论了TCP/IP协议族中传输控制协议TCP、用户数据报协议UDP和网际控制报文协议ICMP等原理和应用。     

Data packet intercepting on the internet: How and why? A closer look at existing data packet-intercepting tools

The Internet constitutes a means of communication in terms of which millions of messages and huge chunks of data are electronically sent millions of miles across the globe each day thanks to the Transmission Control Protocol/Internet Protocol (TCP/IP). One of the functions of the TCP/IP is to break up each of these messages into smaller entities of equal length. Such an entity is known as a ‘datagram’ or a ‘data packet’. The Internet, however, already disposes of many tools/applications that can intercept a TCP/IP datagram. The reasons for intercepting a TCP/IP datagram vary from application to application. Some applications, for example, intercept a data packet or datagram to execute harmful effects on it, mostly to terrorize the sender and/or the receiver of such packet or datagram. Some applications, on the other hand, might want to monitor a packet or datagram for security reasons. Still other applications might merely want to intercept a data packet or datagram to manage flow control and other network-management aspects. Packet intercepting can, therefore, be a useful tool in any TCP/IP-based application aimed at monitoring or intercepting TCP/IP data packets or datagrams.     

Architecture for a hardware-based, TCP/IP content-processing system

The transmission control protocol is the workhorse protocol of the Internet. Most of the data passing through the Internet transits the network using TCP layered atop the Internet protocol (IP). Monitoring, capturing, filtering, and blocking traffic on high-speed Internet links requires the ability to directly process TCP packets in hardware. High-speed network intrusion detection and prevention systems guard against several types of threats. As the gap between network bandwidth and computing power widens, improved microelectronic architectures are needed to monitor and filter network traffic without limiting throughput. To address these issues, we've designed a hardware-based TCP/IP content-processing system that supports content scanning and flow blocking for millions of flows at gigabit line rates. The TCP splitter2 technology was previously developed to monitor TCP data streams, sending a consistent byte stream of data to a client application for every TCP data flow passing through the circuit. The content-scanning engine can scan the payload of packets for a set of regular expressions. The new TCP-based content-scanning engine integrates and extends the capabilities of the TCP splitter and the old content-scanning engine. IP packets travel to the TCP processing engine from the lower-layer-protocol wrappers. Hash tables are used to index memory that stores each flow's state.     

TCP switching: exposing circuits to IP

A simple technique could eliminate choke points on the the Internet. TCP switching, which integrates circuit switching benefits in the packet-switched Internet, demonstrates the possibilities. The research presented focuses on how the existing IP infrastructure can incorporate fast, simple (and perhaps optical) circuit switches. Several approaches to this already exist, but we propose a technique called transmission control protocol (TCP) switching in which each application flow (usually an individual TCP connection) triggers its own end-to-end circuit creation across a circuit-switched core. Based on IP switching, TCP switching incorporates modified circuit switches that use existing IP routing protocols to establish circuits. Routing occurs hop by hop, and circuit maintenance uses soft state, that is, it is removed through an inactivity time-out     

TCP in a wireless world

Mobile wireless is one of the more challenging environments for the Internet protocols, and for TCP in particular. One approach to supporting the wireless environment is the so-called “walled garden”. Here the transport protocol used within the mobile wireless environment is not TCP, but is instead a transport protocol that has been specifically adapted to mobile wireless. In this model, Internet applications interact with an application gateway to reach the wireless world, and the application gateway uses a wireless transport protocol and potentially a modified version of the application data to interact with the wireless device. The most common implementation of this approach is to extend a Web client into the mobile wireless device, using some form of proxy server at the boundary of the wireless network and the Internet. This is the approach adopted by the Wireless Access Protocol (WAP) Forum. An alternative is to allow mobile wireless devices to function as any other Internet-connected device. This approach requires some form of end-to-end direct IP continuity and an associated end-to-end TCP functionality, where the TCP path straddles both wired and wireless segments. Ensuring the efficient operation of TCP in this environment becomes integral to the development of the environment itself; the problem is no longer one of adjusting TCP to match the requirements of the wireless environment, but one of providing seamless interworking between the wired and wireless worlds     

IP网络实时视频流的传输控制算法AVTC的研究

随着实时音视频流和多播应用的发展，越来越多的非TCP流将出现在IP网上，它们可能和TCP流不公平地竞争网络带宽．针对TFRC算法存在的一些缺陷、Rtt的计算以及具体的实现等问题进行了讨论，并提出了IP网的自适应实时视频传输控制算法AVTC(adaptive video transmission control)．在AVTC算法中，发送端通过从接收端得到当前网络的状态信息，从而估计得到比较合适的发送速率，并动态地调整发送端的发送速率以适合当前网络的状况．AVTC算法满足实时视频流传输的实时性要求以及与TCP流公平地分享带宽的TCP友好性要求．     

基于TCP/IP硬件协议栈的智能仪器网络接口设计

目前嵌入式应用系统，特别是智能仪器中常采用51系列的微控制器为核心。为了实现智能仪器与Internet连接的功能，通过应用网络接口芯片W3100A与51系列的微控制器接口来实现TCP／IP协议栈，用于数据的快速传输和共享，标准协议（TC/IP）为数据的可靠传输提供了保证。提出了一种利用Internet获得智能仪器中的实时及历史数据的可行性方案。     

对FASTTCP网络拥塞控制优缺点的分析

随着互联网规模与应用的扩大，网络环境变得复杂，传统的拥塞控制已经不能适应高速网络，FASTTCP因此应运而生。通过仿真实验与传统TCPReno进行对比，发现FASTTCP确实有很大的提高，但也存在问题需要改进。