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1.
Cloud computing has become the real trend of enterprise IT service model that offers cost-effective and scalable processing. Meanwhile, Software-Defined Networking (SDN) is gaining popularity in enterprise networks for flexibility in network management service and reduced operational cost. There seems a trend for the two technologies to go hand-in-hand in providing an enterprise’s IT services. However, the new challenges brought by the marriage of cloud computing and SDN, particularly the implications on enterprise network security, have not been well understood. This paper sets to address this important problem.We start by examining the security impact, in particular, the impact on DDoS attack defense mechanisms, in an enterprise network where both technologies are adopted. We find that SDN technology can actually help enterprises to defend against DDoS attacks if the defense architecture is designed properly. To that end, we propose a DDoS attack mitigation architecture that integrates a highly programmable network monitoring to enable attack detection and a flexible control structure to allow fast and specific attack reaction. To cope with the new architecture, we propose a graphic model based attack detection system that can deal with the dataset shift problem. The simulation results show that our architecture can effectively and efficiently address the security challenges brought by the new network paradigm and our attack detection system can effectively report various attacks using real-world network traffic.  相似文献   
2.
In this digitalised world, crossing boundaries between life domains is becoming increasingly easy. We are constantly faced with the need to define whether we are online or offline, and technology management is now an integral part of daily life. Technology management, which is affected by the individual's networking position, has different components: connectivity management, online self-presentation and privacy management. The objective of this study is to explore technology management strategies among working adult students. The study identifies three networking positions: socio-affective enthusiasts, context-contingent pragmatists and pragmatic avoiders. These three groups have specific approaches to technology management.  相似文献   
3.
内容中心网络中基于差异化缓存通告的混合路由机制   总被引:1,自引:0,他引:1  
针对内容中心网络(CCN)节点暂态缓存的高效利用问题,将数据场的思想引入到CCN转发决策中,该文提出一种基于差异化缓存通告的混合路由机制。缓存通告时,依据内容活跃等级和缓存驻留概率,执行差异化的内容通告和势能辐射;路由查找时,针对“持久稳定”的内容源和“动态可变”的临时缓存副本,分别构建全局导向和局域吸引势能辐射场,实现兴趣包请求的全局路由和局部就近应答。仿真结果表明,该机制减小了内容请求时延,提高了缓存命中率,以少量额外的开销提升了CCN网络整体的内容分发性能。  相似文献   
4.
Software networking devices running on commercial-off-the-shelf hardware offer more flexibility and less performance than high-end, dedicated, networking devices. However, this lack of performance can be compensated, to some extent, by multi-core processors that can manage network packets in parallel. In order to efficiently utilize multi-core architectures, the processing load and the network traffic must be properly balanced to optimize the inter-core communication. Here, we analyze the traffic distribution on a per-packet and per-flow basis and verify the performance of the Linux Bridge networking device. A new, adaptive, traffic-distribution method is proposed, which combines packet-based and flow-based traffic distributions. The method was experimentally validated by two test cases – the “worst-case” scenario, with one dominant flow, and the “backbone-link” scenario, with a large number of flows that have a similar packet rate. In the case of one dominant flow, the performance in traffic throughput is improved by a factor of 2.8 by engaging four processing cores. In the case of a large number of traffic flows, the performance remains similar to the existing flow-based methods.  相似文献   
5.
Software Defined Networks (SDNs) based on the OpenFlow (OF) protocol export control-plane programmability of switched substrates. As a result, rich functionality in traffic management, load balancing, routing, firewall configuration, etc. that may pertain to specific flows they control, may be easily developed. In this paper we extend these functionalities with an efficient and scalable mechanism for performing anomaly detection and mitigation in SDN architectures. Flow statistics may reveal anomalies triggered by large scale malicious events (typically massive Distributed Denial of Service attacks) and subsequently assist networked resource owners/operators to raise mitigation policies against these threats. First, we demonstrate that OF statistics collection and processing overloads the centralized control plane, introducing scalability issues. Second, we propose a modular architecture for the separation of the data collection process from the SDN control plane with the employment of sFlow monitoring data. We then report experimental results that compare its performance against native OF approaches that use standard flow table statistics. Both alternatives are evaluated using an entropy-based method on high volume real network traffic data collected from a university campus network. The packet traces were fed to hardware and software OF devices in order to assess flow-based data-gathering and related anomaly detection options. We subsequently present experimental results that demonstrate the effectiveness of the proposed sFlow-based mechanism compared to the native OF approach, in terms of overhead imposed on usage of system resources. Finally, we conclude by demonstrating that once a network anomaly is detected and identified, the OF protocol can effectively mitigate it via flow table modifications.  相似文献   
6.
针对当前网络中降低数据包传输时延的机制复杂且在数据包的匹配过程中存在较高的处理时延,提出了基于软件定义网络(SDN)架构的虚拟链式快速通道路由模式(Chain-Like Hyperchannel Routing Mode,CHRN),在将不同优先级的数据流映射到不同的虚拟传输网络上的同时,时延敏感型数据将采用不查表的快速转发方式来降低数据包的处理时延.实验证明,这种方式在不影响普通数据包传输的条件下,有效提高了时延敏感型数据的传输效率.  相似文献   
7.
分析了云计算数据中心的存储需求,探讨了NAS和SAN的工作机制,对其在虚拟机环境下的性能进行比较测试.实验表明,在虚拟机环境下NAS和SAN之间的性能差异小于10%,远小于传统应用环境中的性能差异.综合考虑存储系统的可扩展性、易管理性等多种因素,在虚拟机环境下使用NAS存储是更为合理的方案.  相似文献   
8.
针对频率广播机制在短波组网中的弊端,比较了多种解决方案,提出了一种基于频率分时复用和反向动态唤醒的短波台站频率广播策略,为短波组网项目提供一种短波频率广播机制的实现方案。  相似文献   
9.
The use of content-based services over telecom network infrastructures is growing rapidly as user-generated content, over-the-top videos, on-demand videos, personalized TV with CatchUp/PauseLive features, etc. are becoming increasingly popular. To meet the demands of such services, content-delivery networks (or content-distribution networks (CDN)) are being deployed over these telecom network infrastructures in a similar fashion as traditional CDNs. However, with the increasing energy consumption and carbon footprint of the information and communication technology (ICT) industry, these CDNs must be designed to include energy-efficiency measures. Our study presents energy-consumption models, analysis, and content-placement techniques for different types of CDNs over telecom networks to reduce energy usage. Our suggested content-placement strategies exploit variations between storage power consumption and transmission power consumption to achieve energy efficiency. Also, in dynamic traffic scenarios, our content-placement strategies utilize the time-varying traffic irregularities of content-based services. By creating more content replicas during peak load and less replicas during off-peak load, dynamic approaches can save substantial amount of energy. Illustrative numerical examples show a significant improvement in the CDN energy efficiency using these approaches.  相似文献   
10.
介绍智能家居系统中的常用组网技术,分析智能家居系统的实际需求,然后结合各类组网技术的适用性,提出一种以EIB为基础,同时融合IrDA和Wi-Fi技术的智能家居系统组网技术,并在上海市长宁区某街道的一个智能家居体验点中进行应用。该组网技术兼顾满足了智能家居系统高可靠性、高稳定性以及高速性的需求,具有一定的应用前景。  相似文献   
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