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Intrusion Tolerance in Wireless Environments
The work program described in the proposal for this on-going PhD thesis at the LASIGE Research Centre / DI-FC-UL is concerned with the investigation of intrusion-tolerant agreement protocols for wireless ad-hoc networks. The broader goal is to design, implement, and evaluate agreement protocols tolerant to arbitrary faults that are able to exploit the particular characteristics of wireless ad-hoc environments in order to maximize their performance. Such protocols, specically tailored for ecient operation in wireless networks, represent a novel contribution and an important step for- ward for the deployment of critical services in these environments. Wireless ad-hoc networks, however, present several challenges to the system architect. They are typically resource-constrained both in terms of computing power and communication capacity. For example, they have less bandwidth than wired local-area-networks, their shared communication medium leaves them more vulnerable to denial-of-service attacks, and their nodes are usually mobile devices with limited energy and computing capa- bilities. The inherent unreliability of radio communications is another signi- cant challenge. Pervasive physical phenomena - such as poor atmospheric conditions, fading, or interference - contribute to signal loss. On top of this, link-layer reliability is usually based on best-eort mechanisms (e.g., CSMA/CA). Collisions in wireless networks are hard to detect. The ra- dio communication is usually half-duplex, which makes impossible for the transmitter to sense the channel for collisions while transmitting data. Some proposals for MAC layer protocols that support collision detection on the receiver side do exist [32, 46], but so far the ability to provide reliable colli- sion detection in wireless environments remains a major technical challenge. Additionally, the very nature of wireless nodes, which are often mobile, may lead to arbitrary periods of disconnection. Finally, the presence of malicious elements, which is likely given the critical services potentially provided by wireless ad-hoc networks, further intensies the diculty of designing agreement protocols for wireless envi- ronments. The system should be able to provide correct operation even if some of its nodes fall under the control of a sophisticated adversary.
Start Date: 2006-01-01
End Date: 2010-06-30
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