一种提供时延QoS保障的无线网络MAC协议

本文从提高系统工作效率的角度出发,提出了一种基于无争用集中控制的忙队列周期查询(BQPO)控制协议.该协议为时延QoS要求较高的无线终端提供了稳定可靠的保障,通过系统建模分析获得了系统的信息分组平均等待时间的解析结果.仿真实验结果表明理论分析和仿真实验的一致性与合理性,与PCF控制方式相比,BQPO协议具有更好的稳定性和时延QoS保障.     

Network Address Translation for the Stream Control Transmission Protocol

Network address translation is widely deployed in the Internet and supports the Transmission Control Protocol and the User Datagram Protocol as transport layer protocols. Although part of the kernels of all recent Linux distributions, namely, the FreeBSD 7 and the Solaris 10 operating systems, the new Internet Engineering Task Force transport protocol - Stream Control Transmission Protocol - is not supported on most NAT middleboxes yet. This article discusses the deficiencies of using existing NAT methods for SCTP and describes a new SCTP-specific NAT concept. This concept is analyzed in detail for several important network scenarios, including peer-to-peer, transport layer mobility, and multihoming.     

传输层网络编码性能分析

底层网络随机丢包导致的传输控制协议(TCP)传输性能恶化的问题由来已久.为了保障TCP的吞吐量在无线网络环境下依然能够保持在较好的性能,通过分析传输层网络编码(TCP/NC)协议的基本原理,分别利用NS-2搭建了软件仿真平台和Wi-Fi开发板搭建了硬件仿真平台.在2种平台上分别测试了传输层网络编码的性能并且分析了TCP的拥塞窗口和吞吐量性能.实验结果表明:传输层网络编码能够有效克服底层的随机丢包带来的影响,提升TCP吞吐量.     

流控制传输协议研究

文章介绍了流控制传输协议(SCTP)的主要特点:支持多穴主机,支持消息的无序递交,提供端到端的可靠性,提供面向消息的传输,提供相对TCP增强的流量控制和拥塞控制,提供更好的安全性和可扩展性;分析了SCTP的主要应用,强调作为一种通用的传输层协议SCTP是今后发展的方向;综合考察了当前SCTP的研究进展,并给出了相关结论,认为SCTP是一种功能强大的传输层协议.     

新一代流控制传输协议SCTP

详细描述了流控制传输协议ＳＣＴＰ。ＳＣＴＰ设计用于在ＩＰ网络上传输ＰＳＴＮ信令,但它可以有更广阔的用途。     

Design and Implementation of Embedded Transmission Control Protocol/Internet Protocol Network Based on System-on-programmable Chip

A scheme of transmission control protocol/Internet protocol（TCP/IP） network system based on system-on-programmable chip（SOPC） is proposed for the embedded network communication. In this system, Nios processor, Ethernet controller and other peripheral logic circuits are all integrated on a Stratix Ⅱ field programmable gate array （FPGA） chip by using SOPC builder design software. And the network communication is realized by transplanting MicroC/OS Ⅱ （uC/OS Ⅱ ） operation system and light weight Internet protocol（LwIP）. The design idea, key points and the structures of both software and hardware of the system are presented and ran with a telecommunication example. The experiment shows that the embedded TCP/IP network system has high reliability and real-time performance.     

浅析流控传输协议(SCTP)

随着技术的发展,Intemet和电话网PSTN之间的网络融合已经是一种必然的趋势,如何在IP网上实现语音业务,而且同样具有PSTN的业务质量和安全性保证,这就需要能够在IP网上既可以实现数据传输,也可以实现控制信令的传输。SCTP流控协议就是这样一种协议。本文将详细介绍协议的框架,分析协议的功能,分析此协议之所以能成为下一代网络的基本协议的原因。     

On SCP Overload Control in Mobile Intelligent Network Based on Queue Size

1IntroductionIntelligent network,an affiliated network over com-munication network,is introduced for the quick provi-sion of newservices[1 ~2].In the structure of intelligentnetwork,a Service Control Point(SCP) serves a lot ofService Switch Point(SSPs)[3 ~4].It is a veryi mportanttopic that howto guarantee the Qos of SCP (e .g.thenumber of successfully processed calls per unit ti me)whenthe network becomes overloadedinthis centralizednetwork structure . There were many studies about the…     

流控传输协议SCTP的研究

IETF正式把SCTP标准化为RFC2960，作为一种在IP网上传输七号信令消息的新型传输协议，它继承了TCP和UDP的优点，同时增加了一些新特性，特别是多宿和多流，因此吸引了人们的广泛关注。这里首先要介绍了SCTP产生的背景，接着详细介绍了它所具有的一些特性，最后指出它存在的问题和面临的挑战。     

天地一体化信息网络协议体系与传输性能简析

对于中国天地一体化信息网络(ISTIN)的构建,针对可能采用的两种网络协议体系,即传输控制协议(TCP)/IP和容迟容断网络(DTN),以3颗地球静止轨道(GEO)卫星组成天基骨干网络为例,分析了3种基本传输场景下的主要挑战,通过计算机半实物仿真开展了协议传输性能的测试。试验结果表明:尽管DTN协议与TCP-Hybla改进协议能够获得较好的传输性能,由于时延与误码率(BER)等参数存在较大的动态范围,没有一种协议能够在所有传输场景下保持传输性能始终最优。天地一体化信息网络协议体系的性能仍有待进一步提高。     

基于SDH传输网络的防爆工业监控系统

介绍了应用SDH光纤网络传输的防爆工业监控系统的整体设计,并结合一个特殊环境的油田项目进行了应用。     

一种新的卫星网络传输控制协议

为了解决TCP协议在卫星通信网络中性能差的问题,该文提出了一种适合卫星网络的新型传输控制协议TP-Satellite。为了加速在连接开始阶段拥塞窗口(cwnd)增涨速度,该协议不再采用传统的Slow Start策略,而是采用一种新的窗口增涨策略超起始策略。为了将误码与网络拥塞造成的数据丢失区分开,协议还采用基于不同优先级IP数据交错发送的丢失判断策略。另外,协议采用了主动周期应答策略。通过理论分析和仿真比较,TP-Satellite协议能够迅速提升数据发送速率和有效地区分数据丢失原因,明显提高前向链路的吞吐量,同时降低反向链路的带宽占用。     

多路径传输控制协议技术综述

随着互联网的应用发展,用户对带宽的需求日益增大。同时,伴随着宽带接入技术的发展,终端可以同时具有多条网络链接,然而传统传输控制协议(TCP)采取单路通信,因而造成资源浪费。为此,IETF专门提出了多路径TCP(MPTCP)来实现TCP的多路传输,从而提高链路利用率和协议鲁棒性。本文对国内外MPTCP的最新研究成果进行了总结,包括MPTCP的体系结构、路由和拥塞控制等内容,可为国内研究者进一步深入研究提供参考。     

多路径TCP协议性能分析

现有的网络终端通常配有多个网络接口,被称为多宿主主机,拥有多个可用的IP地址。多路径TCP能够同时使用这些接口进行数据传输,提高数据传输的效率和稳定性。通过搭建真实环境测试平台,剖析了多路径TCP的工作机制,并对多路径TCP的性能进行测试分析。     

卫星网络传输控制协议研究

标准传输控制协议（TCP）直接用于卫星网络,由于其不能够区分丢包和慢启动的长时间需求等导致协议的非适应性。在分析卫星网络影响协议性能因素的基础上,总结了当前针对这些因素造成的不利影响所增加的额外技术,并对现有提高卫星网络TCP性能的方法进行了分类总结,比较了这些TCP的特点,最后指出了卫星网络TCP的未来研究策略和发展趋势。     

无线局域网协议802.11安全性分析

本文从身份认证、通信的机密性、完整性和不可否认性方面对IEEE无线局域网协议802.11的安全机制进行分析,证明了该协议的安全机存在着严重的安全漏洞,实际上该协议的安全机制无法保障无线局域网的安全通信.本文还指出了实际中可能存在的攻击,针对文中提到的漏洞和可能受到的攻击,提出了相应的解决方案.     

Improvement of Transmission Control Protocol for High Bandwidth Applications

Transmission control protocol (TCP) is the widely and dominantly used protocol in today’s internet. A very recent implementation of congestion control algorithm is BBR by Google. Bottleneck bandwidth and round-trip time (BBR) is a congestion control algorithm which is created with the aim of increasing throughput and reducing delay. The congestion control protocols mentioned previously try to determine congestion limits by filling router queues. BBR drains the router queues at the bottleneck by sending exactly at the bottleneck link rate. This is done by the BBR through pacing rate which infers the delivery rate of the receiver and uses this as the estimated bottleneck bandwidth. But when the data rate is high, in the startup phase itself pipe becomes full and leads to some degradation in the Access Point of wireless environments by inducing losses specific to this environment. So the current pacing rate is not suitable for producing higher throughputs. Therefore, in the proposed system named R-BBR, this startup gain should be lower than the current startup gain which eventually would reduce pacing rate to reduce queue pressure in the sink node during the startup phase. The startup phase of BBR is modified to solve the problem of pipe full under high data rate. R-BBR has been evaluated over a wide range of wired as well as wireless networks by varying different factors like startup gain, congestion window, and pacing rate. It is inferred that R-BBR performs better than BBR with significant performance improvement.

     

网络传输协议在视频监控系统设计中的运用

主要分析网络传输协议在视频监控系统设计中的运用.设计者在设计基于网络传输协议的视频监控系统时,要充分考虑将多种视频监控核心服务进行融合,而且在业务设计过程中对于数据的稳定性、事件响应及时性等进行关注,从而进一步实现业务逻辑的高度协调,大大便利使用者的日常使用.     

Deploying Internet Protocol Security in satellite networks using Transmission Control Protocol Performance Enhancing Proxies

Applications that use the reliable Transmission Control Protocol (TCP) have a significant degradation over satellite links. This degradation is mainly a consequence of the congestion control algorithm used by standard TCP, which is not suitable for overcoming the impairments of satellite networks. To alleviate this problem, two TCP Performance Enhancing Proxies (PEPs) can be deployed at the edges of the satellite segment. Then these PEPs can use different mechanisms such as snooping, spoofing and splitting to achieve a better TCP performance. In general, these mechanisms require the manipulation of the Internet Protocol (IP) and TCP headers that generates a problem when deploying the standard IP security (IPsec) protocol. The security services that IPsec offers (encryption and/or authentication) are based on the cryptographic protection of IP datagrams, including the corresponding IP and TCP headers. As a consequence, these cryptographic protections of IPsec conflict with the mechanisms that PEPs use to enhance the TCP performance in the satellite link. In this article, we detail the reasons that cause this conflict, and we propose three different approaches to deploy IPsec in a scenario with TCP PEPs. Our proposals provide different trade‐offs between security and TCP performance in some typical scenarios that use satellite networks. Copyright © 2012 John Wiley & Sons, Ltd.     

一种短波高效数据传输协议关键技术的设计与实现

针对未来实战对短波数据传输的要求,在美军第三代短波网络标准低速数据链路协议(LDL)基础上,提出了将数据分包传输、包长自适应及递增冗余校验等技术应用于短波通信,实现在复杂的短波信道条件下数据高效、可靠传输的新思路。阐述了关键技术的具体实现方式,给出了数据分包传输、包长自适应及递增冗余等技术的计算机仿真结论。