软件定义网络环境下DoS攻防实验设计

SDN作为一种新型网络架构,对网络进行集中控制、拥有全局网络视图和灵活编程能力,很大程度上代表了未来网络的发展方向.但SDN集中控制的特性和数据平面与控制平面的分离,会大大增加受到DoS攻击的可能性.该文首先详细分析了SDN环境下控制平面、数据平面、网络主机等遭受洪范式DoS攻击或隐藏式DoS攻击的不同特点;然后利用轻...     

SYN Flood攻击的检测

为有效防止和避免网络的SYN Flood攻击，本文介绍了SYN Flood攻击的基本原理，国内外研究现状，然后详细描述了两种比较有效和方便实施的防御方法：SYN-cookie技术和地址状态监控。SYN-cookie技术实现了无状态的握手，避免了SYN Flood的资源消耗。地址状态监控的解决方法能够对每一个连接服务器的IP地址的状态进行监控，主动采取措施避免SYN Flood攻击的影响。同时提出自己的解决方案，即从报文段数据层面进行统计分析，通过得到的统计结果比较正常情况下的统计数据来做出是否存在SYN flood攻击的判断。     

基于SDN的DDoS攻击检测技术研究

为了在保证检测准确率的前提下提高检测效率,并优化SDN网络中基于流表特征的DDoS攻击检测算法,主要分析基于流表特征的DDoS攻击检测技术及其存在的不足,提出首先利用主成分分析优化流表特征,从中选出合适的特征子集,并采用支持向量机算法实现分类检测;然后搭建仿真网络环境,利用正常数据集与攻击数据集训练分类器进行测试实验;最后从检测准确率与检测时间两个维度对特征降维前后的检测方法进行对比。实验结果表明,经过特征降维的检测方法在不影响准确率的同时,有效提高了检测速率。     

防火墙防御SYN Flood攻击机制研究

为了有效防御SYN Flood攻击,同时降低防火墙的压力,提出一种防火墙代理的防御SYN Flood攻击机制,并在Linux平台上通过增加防火墙过滤钩子块和修改服务器协议栈进行了实现.该机制是对SYN中继的改进,避免了防火墙与服务器之间的三次握手过程和修改TCP数据包的序列号及确认号的操作.实验结果表明,该机制能够大幅降低防火墙资源消耗,同时具有更好的防御效果.     

抵抗欺骗攻击的DV-Hop定位算法

由于无线传感器网络处于开放性的环境中,很容易受到欺骗攻击,即难以利用DV-Hop算法进行有效定位.针对此问题,本文在分析欺骗攻击模型和DV-Hop算法易受攻击原因的基础上,提出了一种新的抵抗欺骗攻击的DV-Hop定位算法.该算法能对参与未知节点的信标节点进行分组,并根据各个分组的加权平均残差平方和,排除可能含有恶意节点的分组,并通过利用没有恶意节点分组中的所有信标节点进行定位,从而有效抵抗了欺骗攻击.仿真结果表明,当网络中存在欺骗攻击时,DV-Hop算法仍然能够有效地定位.     

软件定义网络技术的动态网络移动目标防御研究

传统的网络防御技术主要是研究静态的、被动的防御手段.针对目前现有网络安全态势具有"易攻难守"的特点,充分利用软件定义网络的控制与转发分离、网络可编程等新特性,设计了一个针对动态网络移动目标防御的动态防御策略方案,提出了一种基于设备指纹识别技术的防DDoS攻击策略.在开放源码的SDN控制器Floodlight上进行了实验...     

无线校园网络钓鱼AP攻击检测技术研究

随着无线校园网络的发展和普及,无线钓鱼攻击更具有隐蔽性和破坏性.通过分析无线钓鱼攻击原理,结合准确性、稳定性、安全性和检测效率等因素提出3种钓鱼攻击AP检测技术:在服务端应用基于构建特定MAC管理帧的检测技术,在客户端应用基于路由跟踪和HDT算法的检测技术.综合使用多种检测技术可以提高检测能力,使无线校园网络保持高效稳定的运行状态,为师生提供安全可靠的服务.     

openFlow/SDN控制器路由算法的研究

基于open Flow的SDN是新兴的网络技术,它将控制平面与数据平面分离,降低了网络管理的难度。首先介绍了SDN的思想及结构设计SDN控制器的架构,对SDN控制器路由算法进行分析,提出性能更好的算法方案,最后表明未来研究的方向。     

基于现代网络的深度学习应用协议识别技术研究与实现

在高速网络环境下,随着用户对端口的自由使用,点对点网络及加密协议开始得到广泛应用。通过创建一个网络协议分析库,深入网络数据包,进行深度学习的应用层协议分类与分析识别,以提高协议检测的准确性。根据大量主流应用程序的流特征进行深度学习,建立应用协议特征库,通过算法实现应用层协议的识别。研究一种应用于APT攻击防御系统、网络入侵检测系统与Web审计系统的应用层协议识别技术,可提高对APT攻击防御判断的准确性。     

SDN技术在云IDC网络中的应用研究

在新的云计算模式下,传统IDC树形层次化结构的网络架构在流量工程、虚拟机动态迁移、负载均衡和多租户隔离等方面存在诸多不足。作为一种新型网络创新架构,软件定义网络（SDN）技术为解决以上云数据中心的问题提供了一种新的解决方案。分析并阐述了SDN技术在IDC互联网络和IDC内部网络中的应用场景,并介绍了SDN技术的关键问题与云计算管理平台的融合。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.