使用Winpcap开发网络数据包分析器

使用Winpcap开发包实现了一个网络数据包分析器。该分析器可以捕获UDP或TCP数据包,并对数据包头进行分析。     

VC下QNX实时系统的通信

对QNX实时嵌入式系统进行研究,明确实时操作系统的概念,QNX操作系统的特点。在TCP／IP协议,以及QNX的多线程编程技术理论的支持下实现了QNX嵌入式系统的通信编程,并对该通信的应用进行了简要的说明。     

一种新的采用TCP封装的IPSec广域网加速通信研究

本文首先针对广域网上TCP通信比较慢等问题进行了分析,接着再对IPSec体系进行剖析。为了提高IPSec保护的TCP数据的广域网通信性能,本文提出了采用ACK代理、组包和压缩以及IPSecover TCP等机制的TTAP协议,并给出了协议实现的结构和流程。为了对协议模型进行验证,本文以FreeSWAN软件为基础,对TTAP协议进行了设计和实现,并提供了性能测试数据作为比较,最后对新系统的性能进行了分析。     

嵌入式TCP/IP协议栈的简化和优化

嵌入式TCP/IP协议网络是嵌入式系统的典型应用,其网络协议必须进行适当的简化和优化,以适应在可靠性、成本、功耗等方面的严格要求。结合嵌入式系统的一般特点,分析TCP/IP协议栈,提出在特定应用中嵌入式网络中如何选择TCP/IP协议栈的关键协议,进而提出协议栈的简化和优化方法。     

时间触发机制在工业以太网中的应用

本文针对工业以太网时间确定性方面的缺陷,提出了一种时间触发以太网架构,通过改进通信协议栈的结构来改变以太网的媒体访问策略,从而大大提高了整个网络的时间确定性。工业现场的设备使用时间触发以太网互连,不但可以满足各任务时间精确性,而且可以使现场的设备和Internet上的任意主机进行通信。     

远程监护系统中ZigBee网关的设计

ZigBee是一种新兴的无线通信技术,本文介绍了一种基于ZigBee的无线网关设计方法并应用到远程监护系统中。完成后的网关设备能实现数据从ZigBee无线传感器网络到互联网的转换,且有较好的通用性,有着广泛的应用前景。详述了该基于双MCU网关的硬件设计方案和在ZigBee协议与TCP/IP协议传输数据的软件编程思路。     

Performance enhancement of TCP in high-speed networks

GridFTP is a secure and reliable high-performance parallel data transfer protocol used for transferring massive amounts of widely distributed data. Currently it allows users to configure the number of parallel streams and socket buffer size. However, its tuning procedure for optimal combination is a time consuming task. The socket handlers and buffers are important system resources and must therefore be carefully managed. In this paper, we propose a scheme to achieve high throughput even with a smaller buffer size, and also derive a regression equation to predict the optimal combination of resources for a connection. To improve the performance, the TCP based on our scheme obtains higher throughput and spends less memory for the same throughput than the original TCP scheme. In addition, the regression equation is verified by comparing measured and predicted values, and we apply the equation to an actual experiment on the KOrea advanced REsearch Network (KOREN). The result demonstrates that the equation provides excellent predictions with only an 8% error boundary.     

Dynamic TCP Acknowledgment and Other Stories about e/(e - 1)

Abstract. We present the first optimal randomized online algorithms for the TCP acknowledgment problem [3] and the Bahncard problem [5]. These problems are well known to be generalizations of the classical online ski-rental problem, however, they appeared to be harder. In this paper we demonstrate that a number of online algorithms which have optimal competitive ratios of e/(e-1) , including these, are fundamentally no more complex than ski rental. Our results also suggest a clear paradigm for solving ski-rental-like problems.     

ER-TCP: an efficient TCP fault-tolerance scheme for cluster computing

This paper proposes a novel scheme, named ER-TCP, which transparently masks the failures happened on the server nodes of a cluster from clients at TCP connection granularity. In this scheme, TCP connections at the server side are actively and fully replicated to remain consistency so as to be transplanted over healthy parts during failure. A log mechanism is designed to cooperate with the replication to achieve small sacrifice on the performance of communication and makes the scheme scales beyond a few nodes, even when they have different processing capacities. We built a prototype system at a four-node cluster with ER-TCP, and conducted a series of experiments on that. The experimental result told us that ER-TCP has relatively small penalty on the communication performance, especially when it is used to synchronize multiple replicas. The results of real applications show that ER-TCP will incur small sacrifice on performance of web server at light load, and it can be used to distribute files very efficiently and reliably.

多参数变送器的工业以太网接口设计

以ATmega128单片机为多参数变送器研制工业以太网通信接口,使用了高集成度的以太网控制芯片来实现数据链路层和物理层的功能;利用TCP、UDP、PING、IP、ARP五个协议组成一个小型化的TCP/IP协议栈;在应用层选用了Modbus/TCP协议.在流量测试过程中,设计的上位机软件与通信接口配合实验,取得了较好的设计效果.对传统仪表和控制装置设计工业以太网接口以及现场设备的网络化,都具有一定的应用和推广价值.