scispace - formally typeset
Search or ask a question
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
More filters
Proceedings ArticleDOI
12 Jun 2007
TL;DR: Several DoS impact metrics that measure the quality of service experienced by end users during an attack are proposed, and compare these measurements to application-specific thresholds.
Abstract: Denial-of-service (DoS) research community lacks accurate metrics to evaluate an attack's impact on network services, its severity and the effectiveness of a potential defense. We propose several DoS impact metrics that measure the quality of service experienced by end users during an attack, and compare these measurements to application-specific thresholds. Our metrics are ideal for testbed experimentation, since necessary traffic parameters are extracted from packet traces gathered during an experiment.

4 citations

Proceedings ArticleDOI
20 Jun 2011
TL;DR: A platform-independent mechanism to partition a large network experiment into a set of small experiments that are sequentially executed, exposing the fundamental trade off between the simplicity of the partitioning and experimentation process, and the loss of experimental fidelity.
Abstract: Understanding the behavior of large-scale systems is challenging, but essential when designing new Internet protocols and applications. It is often infeasible or undesirable to conduct experiments directly on the Internet. Thus, simulation, emulation, and testbed experiments are important techniques for researchers to investigate large-scale systems. In this paper, we propose a platform-independent mechanism to partition a large network experiment into a set of small experiments that are sequentially executed. Each of the small experiments can be conducted on a given number of experimental nodes, e.g., the available machines on a testbed. Results from the small experiments approximate the results that would have been obtained from the original large experiment. We model the original experiment using a flow dependency graph. We partition this graph, after pruning uncongested links, to obtain a set of small experiments. We execute the small experiments in two iterations. In the second iteration, we model dependent partitions using information gathered about both the traffic and the network conditions during the first iteration. Experimental results from several simulation and testbed experiments demonstrate that our techniques approximate performance characteristics, even with closed-loop traffic and congested links. We expose the fundamental trade off between the simplicity of the partitioning and experimentation process, and the loss of experimental fidelity.

4 citations

01 Jan 2013
TL;DR: The first solution, flow-based scenario partitioning (FSP), is a platform-independent mechanism to partition a large network experiment into a set of small experiments that are sequentially executed, and EasyScale is a new framework for easily configuring a large-scale network security experiment on an emulation testbed.
Abstract: One of the major challenges that network researchers and operators face today is the lack of reliable and scalable network testbeds. Since it is often infeasible to perform experiments directly on a production network or build analytical models for complex systems, researchers often resort to simulation or downscaled testbed experiments. However, designing a downscaled experiment that can faithfully represent a large-scale experiment is often challenging. The results of a non-representative experiment can be misleading and unexpected bugs may not be discovered until the Internet protocol or application is deployed into an operational network. In this work, we present two solutions to enable large-scale network experiments. Our first solution, flow-based scenario partitioning (FSP), is a platform-independent mechanism to partition a large network experiment into a set of small experiments that are sequentially executed. Each of the small experiments can be conducted on a given number of experimental nodes, e.g., the available machines on a testbed. Results from the small experiments approximate the results that would have been obtained from the original large experiment. Experimental results from several simulation and testbed experiments demonstrate that our techniques approximate performance characteristics, even with closed-loop traffic and congested links. Our second solution, EasyScale, aims to bridge the current gap between emulation testbed users and large-scale security experiments possibly using multiple scaling techniques. EasyScale is a new framework for easily configuring a large-scale network security experiment on an emulation testbed. Multiple scaling techniques, such as full and OS-level virtualization techniques, can be used for different parts of the input experimental topology in order to balance scalability and fidelity. The EasyScale resource allocation scheme considers user-specified fidelity requirements. Additional resources are allocated to the experiment components that are considered to be highly important, in order to increase the experimental fidelity. Our results from distributed denial of service and worm attack experiments demonstrate that EasyScale can easily allocate testbed resources to the critical components in an experiment, lowering the barrier for testbed users to conduct high fidelity yet scalable network security experiments.

4 citations

Proceedings Article
23 Mar 2004
TL;DR: This poster introduces the multi-organization project funded by the National Science Foundation and the Department of Homeland Security entitled "Evaluation Methods for Internet Security Technology".
Abstract: This poster introduces the multi-organization project funded by the National Science Foundation and the Department of Homeland Security entitled "Evaluation Methods for Internet Security Technology". Its main objective is to develop scientifically rigorous testing frameworks and methodologies for representative classes of network attacks and defense mechanisms.

4 citations

Proceedings ArticleDOI
Yan Wu1, Sonia Fahmy1
03 Oct 2005
TL;DR: An important feature of the proposed credit-based distributed protocol is its backward compatibility, which allows legacy IEEE 802.11 stations to coexist with stations adopting the new MAC protocol.
Abstract: Fair bandwidth allocation is critical in wireless communication networks, since the wireless channel is often shared by a number of stations in the same neighborhood. With fair scheduling, bandwidth can be shared by competing flows in proportion to their assigned weights. In this paper, we propose a credit-based distributed protocol for fair allocation of bandwidth in IEEE 802.11 wireless LANs. Our protocol is derived from the distributed coordination function in the IEEE 802.11 medium access control (MAC) protocol. Analytical and simulation results demonstrate that the protocol achieves the desired bandwidth allocations. An important feature of our protocol is its backward compatibility, which allows legacy IEEE 802.11 stations to coexist with stations adopting the new MAC protocol.

4 citations


Cited by
More filters
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