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Author

Sonia Fahmy

Bio: Sonia Fahmy is an academic researcher from Purdue University. The author has contributed to research in topics: Asynchronous Transfer Mode & Wireless sensor network. The author has an hindex of 39, co-authored 217 publications receiving 11177 citations. Previous affiliations of Sonia Fahmy include Ohio State University & Hewlett-Packard.


Papers
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Proceedings ArticleDOI
26 May 2006
TL;DR: This paper investigates the architecture of a unified environment where the virtual online world is not partitioned according to rigid boundaries, but according to an adaptive paradigm and proposes an optimistic scheme that quickly converges.
Abstract: Distributed virtual environments such as massive multi-player games require multiple servers to balance computational load. This paper investigates the architecture of a unified environment where the virtual online world is not partitioned according to rigid boundaries, but according to an adaptive paradigm. Since it is difficult to develop an optimal load balancing algorithm for a unified environment, we propose an optimistic scheme that quickly converges. The cost of frequent migrations is reduced by following a push/push data exchange model. We analyze the computational time costs of such a system and give simulation results to gauge its performance. The simulation results confirm that our load balancing scheme is efficient and can support large numbers of clients.

44 citations

Journal ArticleDOI
TL;DR: A firewall dataflow model composed of discrete processing stages that reflect the processing characteristics of a given firewall is created, which provides a more complete view of what happens inside a firewall, other than handling the filtering and possibly other rules that the administrator may have established.

43 citations

Proceedings ArticleDOI
03 Mar 2009
TL;DR: This paper surveys existing approaches and criticizes their simplicity and the lack of realism, and concludes with guidelines on efficiently improving DoS evaluation, in the short and in the long term.
Abstract: DoS defense evaluation methods influence how well test results predict performance in real deployment. This paper surveys existing approaches and criticizes their simplicity and the lack of realism. We summarize our work on improving DoS evaluation via development of standardized benchmarks and performance metrics. We end with guidelines on efficiently improving DoS evaluation, in the short and in the long term.

43 citations

Book ChapterDOI
18 Sep 2017
TL;DR: BEADS, a framework to automatically generate test scenarios and find attacks in SDN systems, is created and 831 unique bugs are found across four well-known SDN controllers: Ryu, POX, Floodlight, and ONOS.
Abstract: We create BEADS, a framework to automatically generate test scenarios and find attacks in SDN systems. The scenarios capture attacks caused by malicious switches that do not obey the OpenFlow protocol and malicious hosts that do not obey the ARP protocol. We generated and tested almost 19,000 scenarios that consist of sending malformed messages or not properly delivering them, and found 831 unique bugs across four well-known SDN controllers: Ryu, POX, Floodlight, and ONOS. We classify these bugs into 28 categories based on their impact; 10 of these categories are new, not previously reported. We demonstrate how an attacker can leverage several of these bugs by manually creating 4 representative attacks that impact high-level network goals such as availability and network topology.

43 citations

Proceedings ArticleDOI
31 Oct 2008
TL;DR: This first study to compare streaming overlay architectures in real Internet settings, considering not only intuitive aspects such as scalability and performance under churn, but also less studied factors such as bandwidth and latency heterogeneity of overlay participants indicates that mesh-based systems are superior for nodes with high bandwidth capabilities and low round trip times.
Abstract: We compare two representative streaming systems using mesh-based and multiple tree-based overlay routing through deployments on the PlanetLab wide-area experimentation platform. To the best of our knowledge, this is the first study to compare streaming overlay architectures in real Internet settings, considering not only intuitive aspects such as scalability and performance under churn, but also less studied factors such as bandwidth and latency heterogeneity of overlay participants. Overall, our study indicates that mesh-based systems are superior for nodes with high bandwidth capabilities and low round trip times, while multi-tree based systems currently cope better with stringent real time deadlines under heterogeneous conditions.

42 citations


Cited by
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01 Jan 2002

9,314 citations

Journal ArticleDOI
TL;DR: It is proved that, with appropriate bounds on node density and intracluster and intercluster transmission ranges, HEED can asymptotically almost surely guarantee connectivity of clustered networks.
Abstract: Topology control in a sensor network balances load on sensor nodes and increases network scalability and lifetime. Clustering sensor nodes is an effective topology control approach. We propose a novel distributed clustering approach for long-lived ad hoc sensor networks. Our proposed approach does not make any assumptions about the presence of infrastructure or about node capabilities, other than the availability of multiple power levels in sensor nodes. We present a protocol, HEED (Hybrid Energy-Efficient Distributed clustering), that periodically selects cluster heads according to a hybrid of the node residual energy and a secondary parameter, such as node proximity to its neighbors or node degree. HEED terminates in O(1) iterations, incurs low message overhead, and achieves fairly uniform cluster head distribution across the network. We prove that, with appropriate bounds on node density and intracluster and intercluster transmission ranges, HEED can asymptotically almost surely guarantee connectivity of clustered networks. Simulation results demonstrate that our proposed approach is effective in prolonging the network lifetime and supporting scalable data aggregation.

4,889 citations

Journal ArticleDOI
TL;DR: A taxonomy and general classification of published clustering schemes for WSNs is presented, highlighting their objectives, features, complexity, etc and comparing of these clustering algorithms based on metrics such as convergence rate, cluster stability, cluster overlapping, location-awareness and support for node mobility.

2,283 citations

Book
12 Aug 2005
TL;DR: In this article, the authors state several problems related to topology control in wireless ad hoc and sensor networks, and survey state-of-the-art solutions which have been proposed to tackle them.
Abstract: Topology Control (TC) is one of the most important techniques used in wireless ad hoc and sensor networks to reduce energy consumption (which is essential to extend the network operational time) and radio interference (with a positive effect on the network traffic carrying capacity). The goal of this technique is to control the topology of the graph representing the communication links between network nodes with the purpose of maintaining some global graph property (e.g., connectivity), while reducing energy consumption and/or interference that are strictly related to the nodes' transmitting range. In this article, we state several problems related to topology control in wireless ad hoc and sensor networks, and we survey state-of-the-art solutions which have been proposed to tackle them. We also outline several directions for further research which we hope will motivate researchers to undertake additional studies in this field.

1,367 citations