共查询到11条相似文献,搜索用时 47 毫秒
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介绍了无线Ad Hoc网络的特点和面临的安全问题,分析了移动代理在Ad Hoc网络入侵检测系统中的适用性,给出了一种基于移动代理的无线Ad Hoc网络入侵检测系统模型。 相似文献
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高动态无线自组网路由协议设计 总被引:1,自引:1,他引:0
针对节点快速移动过程中网络建立时间较长,数据端到端传输时延无法得到可靠保
障,并且由于维护动态网络连接性造成网络开销较大等方面的问题,提出了一种无线自组网
路由协议,通过分簇算法快速将网络分为多个簇,每个簇包括簇首节点、成员节点和簇间网
关节点。该协议能够应用于快速移动节点构成的高动态无线自组织网络中,实现了先应式和
反应式路由算法进行了有机结合,能够在快速变化的拓扑结构中为未知路由提供优化的路由
结果,利用较小的网络开销实现网络快速构建和数据端到端的实时传输。 相似文献
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Wei‐Peng Chen Yung‐Ching Hsiao Jennifer C. Hou Ye Ge Michael P. Fitz 《Wireless Communications and Mobile Computing》2002,2(1):37-57
It is well known that the performance of TCP deteriorates in a mobile wireless environment. This is due to the fact that although the majority of packet losses are results of transmission errors over the wireless links, TCP senders still take packet loss as an indication of congestion, and adjust their congestion windows according to the additive increase and multiplicative decrease (AIMD) algorithm. As a result, the throughput attained by TCP connections in the wireless environment is much less than it should be. The key problem that leads to the performance degradation is that TCP senders are unable to distinguish whether packet loss is a result of congestion in the wireline network or transmission errors on the wireless links. In this paper, we propose a light‐weight approach, called syndrome, to improving TCP performance in mobile wireless environments. In syndrome, the BS simply counts, for each TCP connection, the number of packets that it relays to the destination host so far, and attaches this number in the TCP header. Based on the combination of the TCP sequence number and the BS‐attached number and a solid theoretical base, the destination host will be able to tell where (on the wireline or wireless networks) packet loss (if any) occurs, and notify TCP senders (via explicit loss notification, ELN) to take appropriate actions. If packet loss is a result of transmission errors on the wireless link, the sender does not have to reduce its congestion window. Syndrome is grounded on a rigorous, analytic foundation, does not require the base station to buffer packets or keep an enormous amount of states, and can be easily incorporated into the current protocol stack as a software patch. Through simulation studies in ns‐2 (UCB, LBNL, VINT network simulator, http://www‐mash.cs.berkeley.edu/ns/ ), we also show that syndrome significantly improves the TCP performance in wireless environments and the performance gain is comparable to the heavy‐weight SNOOP approach (either with local retransmission or with ELN) that requires the base station to buffer, in the worst case, a window worth of packets or states. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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We propose using the TCP decoupling approach to improve a TCP connection's goodput over wireless networks. The performance improvement can be analytically shown to be proportional to
, where MTU is the maximum transmission unit of participating wireless links and HP_Sz is the size of a packet containing only a TCP/IP header. For example, on a WaveLAN [32] wireless network, where MTU is 1500 bytes and HP_Sz is 40 bytes, the achieved goodput improvement is about 350%. We present experimental results demonstrating that TCP decoupling outperforms TCP reno and TCP SACK. These results confirm the analysis of
performance improvement. 相似文献
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A novel method which can detect the possible handoffs for mobile nodes is proposed in this article. The method can be deployed on mobile nodes. So when a possible handoff occurs, mobile nodes can detect and take some necessary actions in time. In this study, the method is also used to optimize the transmission mechanism of Q-TCP. Moreover, the simulation results show that Q-TCP can provide better quality of service (QoS) for mobile nodes when they are moving among different agents. 相似文献
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The transmission control protocol (TCP) is one of the most important Internet protocols. It provides reliable transport services between two end‐hosts. Since TCP performance affects overall network performance, many studies have been done to model TCP performance in the steady state. However, recent researches have shown that most TCP flows are short‐lived. Therefore, it is more meaningful to model TCP performance in relation to the initial stage of short‐lived flows. In addition, the next‐generation Internet will be an unified all‐IP network that includes both wireless and wired networks integrated together. In short, modelling short‐lived TCP flows in wireless networks constitutes an important axis of research. In this paper, we propose simple wireless TCP models for short‐lived flows that extend the existing analytical model proposed in [IEEE Commun. Lett. 2002; 6 (2):85–88]. In terms of wireless TCP, we categorized wireless TCP schemes into three types: end‐to‐end scheme, split connection scheme, and local retransmission scheme, which is similar to the classification proposed in [IEEE/ACM Trans. Networking 1997; 756–769]. To validate the proposed models, we performed ns‐2 simulations. The average differences between the session completion time calculated using the proposed model and the simulation result for three schemes are less than 9, 16, and 7 ms, respectively. Consequently, the proposed model provides a satisfactory means of modelling the TCP performance of short‐lived wireless TCP flows. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献