共查询到20条相似文献,搜索用时 15 毫秒
1.
Junwon Lee Jaeik Cho Jungtaek Seo Taeshik Shon Dongho Won 《Mobile Networks and Applications》2013,18(1):122-128
Recent developments have caused the expansion of various cloud computing environments and services. Cloud computing environments have led to research in the areas of data processing, virtual environments, and access control. Information security is the most important research area for these environments security. In this study, we analyzed typical example of network testbeds, which have been used for malicious activity data collection and its subsequent analysis. Further, we propose an effective malicious network application testbed, which is based on a cloud system. We also verified the performance of our new testbed by comparing real malicious activity with the cloud-based testbed results. 相似文献
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Design and evaluation of an Ethernet-based residential network 总被引:2,自引:0,他引:2
Shuang Deng Bugos A.R. Hill P.M. 《Selected Areas in Communications, IEEE Journal on》1996,14(6):1138-1150
When the information superhighway arrives at the neighborhood, a residential network will connect home appliances to the community access network. These appliances include personal computers, printers, and video clients. Among all local-area network (LAN) protocols, Ethernet is the most economic and the most popular. The unique characteristics of residential networks call for new performance studies. A residential network typically has few nodes and runs different applications than business and academic LANs. Consequently, residential networks have traffic characteristics different from the subject of existing studies. We constructed a residential network testbed to collect typical application traffic statistics. Additional live traffic characterization was obtained from campus networks. Also, we investigated the suitability of Ethernet for video distribution through simulation. This paper discusses the design issues for residential networks and presents a network design that is based on Ethernet technology. Traffic models are established from the actual traffic traces and used for the performance evaluation of residential networks. Furthermore, several future data traffic scenarios are considered with bandwidth up to 6 Mb/s by scaling up current data traffic. The simulation results of the performance suggest that Ethernet can be used as a cost-effective residential network for video and data communications 相似文献
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基于RAS技术上的虚拟传真机系统的设计 总被引:1,自引:0,他引:1
介绍了如何运用远程访问服务技术,实现虚拟传真机系统的功能设计。远程访问服务是一种新兴的网络技术,计算机之间通过连接的远程接入设备建立起RAS(远程访问服务)拨号连接后,就搭建了一个类似局域网的广域网.在众多务件受限的工程场合中.这种解决方案可以方便有效地解决远程计算机之间的数据通讯问题。文中首先介绍了远程通讯原理和虚拟传真机原理.并以单站系统为例分析了系统的结构,详述了在Windows NT平台上提供远程访问服务的服务器端计算机的配置方法和过程.最后给出了建立RAS连接和实现虚拟传真机的主要程序代码。 相似文献
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Marcos Dias de Assunção Radu Carpa Laurent Lefèvre Olivier Glück Piotr Boryło Artur Lasoń Andrzej Szymański Michał Rzepka 《Photonic Network Communications》2017,34(3):396-410
As experimenting with energy-aware techniques on large-scale production infrastructure is prohibitive, a large number of proposed traffic engineering strategies have been evaluated only using discrete-event simulations. The present work discusses (i) challenges towards building testbeds that allow researchers and practitioners to validate and evaluate the performance and quality of energy-aware traffic engineering strategies, (ii) requirements to fulfil when porting simulations to testbeds, and (iii) two proof-of-concept testbeds. One testbed uses and provides software-defined network (SDN) services created on the open-network operating system while the other is a composition of virtual Open vSwitches controlled by the Ryu SDN framework. The aim of the testbeds is to validate previously proposed energy-aware traffic engineering strategies in different environments. We detail the platforms and illustrate how they have been used for performance evaluation. Additionally, the paper compares results obtained in the testbeds with evaluations performed using discrete-event simulations and presents challenges faced while implementing energy-aware traffic engineering mechanisms as SDN services in testbed environments. 相似文献
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The IEEE 802.16‐based WiMAX technology has great potential for the fourth‐generation mobile networks. Some of its service classes use the contention‐based broadcast polling mechanism to request resources. In this paper, we investigate the performance experienced by these services when the network is unsaturated. In particular, we model each subscriber station as an M/G/1 queue where the service time is determined by the parameters of the network configuration and the binary exponential backoff contention resolution algorithm. We develop a fixed‐point analysis to derive analytical expressions for network throughput and packet access delay. The accuracy of the analytical model is validated by comparing it with simulation over a wide range of operating conditions. The implications of various different parameter configurations on the performance are investigated using the analytical model. Moreover, we show that the model can be degenerated to the saturated condition. The utility of both the unsaturated and saturated models is further demonstrated by finding the optimal set of parameter values that maximize the network throughput. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
7.
Smart antennas represent a broad variety of antennas that differ in their performance and transceiver complexity. The superior capabilities of smart antennas, however, can be leveraged only through appropriately designed higher layer network protocols, including at the medium access control (MAC) layer. Although several related works have considered such tailored protocols, they do so in the context of specific antenna technologies. In this paper, we explore the possibility for a unified approach to medium access control in ad hoc networks with smart antennas. We first present a unified representation of the PHY layer capabilities of the different types of smart antennas, and their relevance to MAC layer design. We then define a unified MAC problem formulation, and derive unified MAC algorithms (both centralized and distributed) from the formulation. Finally, using the algorithms developed, we investigate the relative performance trade-offs of the different technologies under varying network conditions. We also analyze theoretically the performance bounds of the different smart antenna technologies when the available gains are exploited for rate increase and communication range increase. 相似文献
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Rerngvit Yanggratoke Jawwad Ahmed John Ardelius Christofer Flinta Andreas Johnsson Daniel Gillblad Rolf Stadler 《International Journal of Network Management》2018,28(2)
We predict performance metrics of cloud services using statistical learning, whereby the behaviour of a system is learned from observations. Specifically, we collect device and network statistics from a cloud testbed and apply regression methods to predict, in real‐time, client‐side service metrics for video streaming and key‐value store services. Results from intensive evaluation on our testbed indicate that our method accurately predicts service metrics in real time (mean absolute error below 16% for video frame rate and read latency, for instance). Further, our method is service agnostic in the sense that it takes as input operating systems and network statistics instead of service‐specific metrics. We show that feature set reduction significantly improves the prediction accuracy in our case, while simultaneously reducing model computation time. We find that the prediction accuracy decreases when, instead of a single service, both services run on the same testbed simultaneously or when the network quality on the path between the server cluster and the client deteriorates. Finally, we discuss the design and implementation of a real‐time analytics engine, which processes streams of device statistics and service metrics from testbed sensors and produces model predictions through online learning. 相似文献
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This article describes the design and implementation of a unique cooperative agents testbed aimed at addressing diverse applications for the difficult problem of seamless personal information networking (SPIN). The real-world SPIN testbed is aimed at two difficult applications. Namely seamless messaging and intelligent network management. Both applications are agent-driven and share agent behavior, and the messaging agents rely on the network management device diagnostic agents for input. The article introduces both problem areas in a common testbed. The first-generation seamless messaging application is described in detail. User-centric seamless messaging assumes heterogeneous communication environments intended to support today's nomadic users. The prototype is introduced for the management of messages across distributed information networks. Its aim is to intercept, filter, interpret, and deliver multimodal messages, be they voice, fax, video, and/or e-mail messages. A user's personal communication agent is charged with delivering messages to the recipient regardless of their target messaging device-a telephone, pager, desktop, wireless laptop, or wireless phone. Personal communication agents classify and act on incoming messages based on their content. A secretary agent routes and tailors urgent messages appropriately to the device manager agent, which delivers the message to a device on which the user may be roaming or active. What makes the seamless messaging application unique is its approach to treating a message in a universal manner, and its ability to mediate between different messaging environments and devices, and to try to track and find the user 相似文献
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Hofmeister R.T. Chung-Li Lu Min-Chen Ho Poggiolini P. Kazovsky L.G. 《Lightwave Technology, Journal of》1998,16(12):2109-2116
Distributed slot synchronization (DSS) is a network-wide packet synchronization technique which coordinates node transmissions so that packets arrive aligned to one another at a reference point in the network, independent of propagation delays. DSS was developed for use in the contention resolution with delay-lines (CORD) project, a DARPA-funded 2.5 Gb/s/λ, wavelength division multiplexer (WDM) optical packet-switched network testbed. In this implementation, it was experimentally demonstrated that the DSS system, operating with 80 MHz control logic, achieves a packet arrival jitter of less than 13 ns with 12 km node spacings. DSS was also shown to be robust against noise and node failure or fiber breaks. The technique is data rate and format independent and can be used in other star, extended ring, or tree-and-branch network architectures for metropolitan area network (MAN) and access applications 相似文献
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This paper proposes and describes R-net, a network with a new reservation access protocol that is very suitable for implementation with optical fibre in high speed local area networks. In the operation of R-net, a framing structure with variable length is superimposed on the network bus to bound the network medium access delay which is a highly desirable feature for real time applications. As long as the frame length constraint is not violated, the performance of R-net network is not limited by operating data rate, and the utilization can be set to unity by choosing the appropriate network parameters. The proposed network has the advantage of efficient throughput approaching unity for most practical configurations, bounded delay, and at normal load, the network protocol has fair access for all nodes and allows dynamic bandwidth allocation between the nodes connected to the network bus. A performance (delay and utilization) comparison between R-net and Expressnet is also presented. 相似文献
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We have designed the heterogeneity inclusion and mobility adaptation through locator ID separation (HIMALIS) architecture to support mobility natively in the New Generation Network. This paper proposes a new distributed mobility scheme in the HIMALIS architecture for supporting seamless mobility for the host moving across access networks of different network-layer protocols. The proposed scheme also supports mobility of an access network. It includes a signaling procedure to redirect downstream traffic from the previous gateway (or previous access router) to the new gateway (or new access router) to minimize the service disruption or packet losses during a handover. The performance results obtained from a testbed implementation in Linux validate the effectiveness of the proposal. The results demonstrate that it can achieve seamless (no packet loss) handovers if overlapped wireless access networks are available. 相似文献
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《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》1998,6(1):150-157
Reconfigurability of processor arrays is important due to two reasons (1) to efficiently execute different algorithms and (2) to isolate faulty processors. An array processor that is reconfigurable by the user any number of times to yield a different topology or to isolate faults is envisaged in this paper. The system has a host or controller that broadcasts a command to the interconnect to configure itself into a particular fashion. The interconnect uses static-RAM programming technology and can be programmed to different configurations by sending a different set of bits to the configuration random access memory (RAM) in the interconnect. We present three designs reconfigurable into array, ring, mesh, or Illiac mesh topologies. The first design provides no redundancy or fault tolerance. The second design is capable of graceful degradation by bypassing faulty elements. The third design is capable of graceful degradation by rerouting. The details of the interconnect and the configuration RAM contents for typical configurations are illustrated. It is seen that reconfigurable interconnect results in a highly reconfigurable or polymorphic computer 相似文献
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TCP Veno: TCP enhancement for transmission over wireless access networks 总被引:18,自引:0,他引:18
Wireless access networks in the form of wireless local area networks, home networks, and cellular networks are becoming an integral part of the Internet. Unlike wired networks, random packet loss due to bit errors is not negligible in wireless networks, and this causes significant performance degradation of transmission control protocol (TCP). We propose and study a novel end-to-end congestion control mechanism called TCP Veno that is simple and effective for dealing with random packet loss. A key ingredient of Veno is that it monitors the network congestion level and uses that information to decide whether packet losses are likely to be due to congestion or random bit errors. Specifically: (1) it refines the multiplicative decrease algorithm of TCP Reno-the most widely deployed TCP version in practice-by adjusting the slow-start threshold according to the perceived network congestion level rather than a fixed drop factor and (2) it refines the linear increase algorithm so that the connection can stay longer in an operating region in which the network bandwidth is fully utilized. Based on extensive network testbed experiments and live Internet measurements, we show that Veno can achieve significant throughput improvements without adversely affecting other concurrent TCP connections, including other concurrent Reno connections. In typical wireless access networks with 1% random packet loss rate, throughput improvement of up to 80% can be demonstrated. A salient feature of Veno is that it modifies only the sender-side protocol of Reno without changing the receiver-side protocol stack. 相似文献
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Pratik K. Biswas Alex Poylisher Ritu Chadha Abhrajit Ghosh 《International Journal of Network Management》2010,20(4):199-218
Integrated network experimentation often combines real nodes with simulated ones, each modeling different portions of the topology, in the same experimental run. They enable new validation techniques and larger experiments than obtainable using real elements alone. Integrated experiments can be particularly useful in testing and validating QoS mechanisms for mobile ad hoc networks (MANETs), when the characteristics of the intermediate wireless network segments are not observable from the end segments, and as a consequence these intermediate segments have to be treated as opaque networks; and also when there is a need to conduct experiments in a real MANET environment at a scale larger than just a few nodes. End‐to‐end QoS assurance for such opaque networks, consisting of admission control and quality adjustment, can be based on techniques for dynamically measuring throughput representing the state of these networks. In this paper, we describe a distributed and hybrid testbed that has been deployed for running large‐scale integrated experiments to demonstrate the efficacy of a measurement‐based QoS solution. The infrastructure for the testbed provides an integrated platform consisting of real nodes running the actual software under test, augmented with a simulated network environment. We define a set of metrics and run experiments to evaluate the effectiveness of the QoS solution as well the performance of the deployed testbed. We propose an alternative architecture that employs a Xen‐based virtualization of the real nodes from the deployed testbed. We compare the performances of the virtualized architecture with the deployed architecture vis‐à‐vis latency and resource utilization. Our goal is to establish benchmarks for running large‐scale experiments on performance and QoS measurements in virtualized environments. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
18.
In this article we illustrate the performance of Transmission Control Protocol in an overlay cognitive radio network under dynamic spectrum access. We show that the performance of TCP in overlay CR networks that implement DSA to be quite different from its performance in conventional networks, which do not allow DSA. The key difference is that secondary users in an overlay CR network have to cope with a new type of loss called service interruption loss, due to the existence of primary users. We demonstrate on an NS2 simulation testbed the surprising result: Excessive radio resource usage leads to a decrease in aggregate TCP throughput. This behavior is in contrast to the behavior of TCP in conventional networks, where throughput increases monotonically with the available radio resource. 相似文献
19.
Gannon D. Alameda J. Chipara O. Christie M. Dukle V. Fang L. Farrellee M. Kandaswamy G. Kodeboyina D. Krishnan S. Moad C. Pierce M. Plale B. Rossi A. Simmhan Y. Sarangi A. Slominski A. Shirasuna S. Thomas T. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2005,93(3):551-563
This work describes an approach to building Grid applications based on the premise that users who wish to access and run these applications prefer to do so without becoming experts on Grid technology. We describe an application architecture based on wrapping user applications and application workflows as Web services and Web service resources. These services are visible to the users and to resource providers through a family of Grid portal components that can be used to configure, launch, and monitor complex applications in the scientific language of the end user. The applications in this model are instantiated by an application factory service. The layered design of the architecture makes it possible for an expert to configure an application factory service with a custom user interface client that may be dynamically loaded into the portal. 相似文献
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《Industrial Electronics, IEEE Transactions on》2009,56(7):2347-2356