一种基于端到端的Ad Hoc网络TCP性能改进方案

由于Ad Hoc网络环境所具有的特殊性,使传统的传输控制协议(TCP)已不再适合这样的环境.在总结分析现有的Ad Hoc网络中TCP性能的改进方案基础上,文章提出一种新的基于端到端检测方法的TCP改进方案,该方案利用数据包的单向传输延迟特性,让接收端检测网络状态,然后通过回送的ACK数据包携带网络状态信息以便让发送端采取合理措施;仿真结果验证了该方案是有效的.     

Best-retransmission count selection for environment optimization over wireless heterogeneous networks

This paper proposes an environment-aware best- retransmission count selected optimization control scheme over IEEE 802.11 multi-hop wireless networks. The proposed scheme predicts the wireless resources by using statistical channel state and provides maximum retransmission count optimization based on wireless channel environment state to improve the packet delivery success ratio. The media access control （MAC） layer selects the best-retransmission count by perceiving the types of packet loss in wireless link and using the wireless channel charac- teristics and environment information, and adjusts the packet for- warding adaptively aiming at improving the packet retransmission probability. Simulation results show that the best-retransmission count selected scheme achieves a higher packet successful delivery percentage and a lower packet collision probability than the corresponding traditional MAC transmission control protocols.     

蚂蚁群行为酷似互联网传输协议

表面上,蚂蚁和互联网好像没什么共同之处,但二者之间却存在惊人的相似性。据物理学家组织网近日报道,斯坦福大学研究人员发现,一种叫做收获蚁的蚂蚁在决定派多少蚂蚁出去找食物时,所用方法和互联网TCP(传输控制协议)确定还有多少带宽可用来传输数据的方法极为相似。     

分布式局域网视音频监控系统

在分析局域网视音频数据多点传输特点的基础上，提出了视音频数据网络传输以及发送和接收的队列管理机制，设计了一套满足系统要求的数据包格式，并描述了接收队列模型。给出了系统的整体结构，以及各组成部分所承担的主要功能，对系统实时解码的原理、解码器的结构及其实现方法进行了讨论。采用分段存储和查询算法，实现了视音频数据的实时存储和精确到秒级的查询。性能测试结果表明，系统的稳定性得到了较大的提高。     

基于TCP的操作系统远程探测技术

利用TCP协议实现中的差异来探测远程操作系统是获取远程操作系统类型信息的一种有效途径。TCP协议上的差异体现为与TCP有关的特征行为和某些字段的特征值。列举了一些探测远程操作系统类型时常使用的TCP协议特征字段和特征行为。将探测的实施分为两个基本步骤:获取远程系统的TCP报文和分析、判断获取的TCP报文。端口扫描是获取远程系统TCP报文前期的一种重要活动,通过对端口扫描原理和三种确定操作系统类型方法的分析,阐明了基于TCP的远程操作系统探测技术的可用性。     

Experimental Evaluation of TCP and ICMP in Network Measurement

Network measurement is an important approach to understand network behaviors, which has been widely studied. Both Transfer Control Protocol （TCP） and Interact Control Messages Protocol （ICMP） are applied in network measurement, while investigating the differences between the measured results of these two protocols is an important topic that has been less investigated. In this paper, to compare the differences between TCP and ICMP when they are used in measuring host connectivity, RTT, and packet loss rate, two groups of comparison programs have been designed, and after careful evaluation of the program parameters, a lot of comparison experiments are executed on the Internet. The experimental results show that, there are significant differences between the host connectivity measured using TCP or ICMP; in general, the accuracy of connectivity measured using TCP is 20%- 30% higher than that measured using ICMP. The case of RTT and packet loss rate is complicated, which are related to path loads and destination host loads. While commonly, the RTF and packet loss rate＂ measured using TCP or ICMP are very close. According to the experimental results, some advices are also given on protocol selection for conducting accurate connectivity, RTF and packet loss rate measurements.     

重传确认延迟--一种改进无线传输控制协议性能的链路层重传方案

基于无线网络中的传输控制协议(TCP)，提出一种新的链路层自动请求重传(ARQ)方案——重传确认延迟，ARQ能对无线链路差错进行恢复。当接收端检测到分组丢失时，对确认帧延迟一段时间，仿真结果表明，在保证无线TCP吞吐量的同时，新算法所需的确认帧数目显著减少。     

WindOWs NT提供的RAS的一个运用

目前,随着我国计算机信息化建设的进一步发展,许多单位或部门的局域网已通过光纤连人Internet,使得局域网内用户能共享局域网资源,并充分享受Internet上巨大的信息资源.然而对于局域网外的许多拨号用户而言,如何共享局域网的资源一直是一个问题.本文提出利用WindowsNT的远程访问服务(RAS),实现局域网外用户通过拨号连入局域网,进而接入Internet的具体方法,并经实际测试,证实方法可行、有效.     

Design of Congestion Control Strategy Based on Pipeline Flux Leak Monitoring Networks

Flow against pipeline leakage and the pipe network sudden burst pipe to pipeline leakage flow for the application objects,network congestion avoidance strategy is designed in pipeline leak monitoring.Based on the property of Markov chain for network data,a new estimator with particle filter is proposed for congestion control in this paper.The proposed scheme can predict the traffic patterns by the decision-making model.To compare with previous scheme based on fuzzy neural network,the proposed scheme can ada...     

第三代移动通信系统中PDCP的数据头压缩技术

PDCP(分组数据会聚协议)主要实现IP数据流的头压缩和解压缩.主要根据PDCP协议中的头压缩技术原理,提出第三代移动通信系统(3G)中的数据头压缩办法.PDCP中的数据头压缩技术,可以在第三代移动通信系统中有效地传输数据,降低头开销.