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.

Energy-Efficient Routing and Data Aggregation in Sensor Networks: An Experimental Study

Abstract: Several sensor network applications, such as environmental monitoring, require data aggregation to an observer (eg, a base station) For this purpose, a data aggregation tree rooted at the observer is constructed in the network to reduce communication overhead and facilitate faster and more reliable results Node clustering can be employed for this purpose, to further balance load among sensor nodes and prolong the network lifetime In this paper, we design and implement a system, iHEED, in which node clustering is integrated with multi-hop routing for TinyOS In iHEED, sensor nodes are clustered prior to constructing the data aggregation tree We consider simple data aggregation operators, such as AVG or MAX We perform experiments on a sensor network testbed to quantify the benefits of integrating hierarchical routing with data aggregation Our results indicate that, by using reduced intra-cluster transmission power and exploiting intra-cluster and inter-cluster data aggregation, network lifetime is prolonged by a factor of 2 to 4, and successful transmissions are almost doubled The overhead of the clustering process is subsumed by tree construction and maintenance overhead Index Temlssensor networks, implementation, clustering, energy efficiency

Worst Case Buffer Requirements For Tcp Over ABR

Abstract: ATM (asynchronous transfer mode) is the technology chosen for the Broadband Integrated Services Digital Network (B-ISDN). The ATM ABR (available bit rate) service can be used to transport ``best-effort'' traffic. In this paper, we extend our earlier work on the buffer requirements problem for TCP over ABR. Here, a worst case scenario is generated such that TCP sources send a burst of data at the time when the sources have large congestion windows and the ACRs (allowed cell rates) for ABR are high. We find that ABR using the ERICA+ switch algorithm can control the maximum queue lengths (hence the buffer requirements) even for the worst case. We present analytical arguments for the expected queue length and simulation results for different number of sources values and parameter values.

EasyScale: Easy mapping for large-scale network security experiments

Abstract: Network emulation enables network security evaluation using unmodified implementations. Experimental fidelity with emulation is higher than simulation through the integration of real hardware and systems, but the scalability of emulation testbeds is limited. Scaling techniques such as virtualization and real-time simulation enable larger scale experiments. Using scaling techniques for network security experiments can, however, require considerable expertise in order to avoid overloading resources. In this paper, we propose a new framework, EasyScale, that aims to bridge the current gap between emulation testbed users and large-scale security experiments possibly using multiple scaling techniques. 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.

Nascent: Tackling Caller-ID Spoofing in 4G Networks via Efficient Network-Assisted Validation

Abstract: Caller-ID spoofing deceives the callee into believing a call is originating from another user. Spoofing has been strategically used in the now-pervasive telephone fraud, causing substantial monetary loss and sensitive data leakage. Unfortunately, caller-ID spoofing is feasible even when user authentication is in place. State-of-the-art solutions either exhibit high overhead or require extensive upgrades, and thus are unlikely to be deployed in the near future. In this paper, we seek an effective and efficient solution for 4G (and conceptually 5G) carrier networks to detect (and block) caller-ID spoofing. Specifically, we propose Nascent, Network-assisted caller ID authentication, to validate the caller-ID used during call setup which may not match the previously-authenticated ID. Nascent functionality is split between data-plane gateways and call control session functions. By leveraging existing communication interfaces between the two and authentication data already available at the gateways, Nascent only requires small, standard-compatible patches to the existing 4G infrastructure. We prototype and experimentally evaluate three variants of Nascent in traditional and Network Functions Virtualization (NFV) deployments. We demonstrate that Nascent significantly reduces overhead compared to the state-of-the-art, without sacrificing effectiveness.

HEED: a hybrid, energy-efficient, distributed clustering approach for ad hoc sensor 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.

Topology Control in Wireless Ad Hoc and Sensor Networks

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.