Team Regal

Overall Objectives
Scientific Foundations
Application Domains
New Results
Other Grants and Activities

Section: New Results

Distributed algorithms

Participants : Luciana Arantes [ correspondent ] , Maria Gradinariu [ correspondent ] , Mathieu Bouillaguet, Pierre Sens, Julien Sopena.

Our current research in the context of distributed algorithms focuses on two main axes. We are interested in providing fault-tolerant and self*(self-organizing, self-healing and self-stabilizing) solutions for fundamental problems in distributed computing. More precisely, we target the following basic blocks: mutual exclusion, resources allocation, agreement and communication primitives. We propose solutions for both static (eg. grid) and dynamic networks (P2P and mobile networks).

Static systems

In 2009, we have proposed a fault tolerant permission-based k-mutual exclusion which does not rely on timers, nor does on failure detectors, neither needs extra messages for detecting node failures. Fault tolerance is integrated in the algorithm itself and it is provided if the underlying system guarantees a Responsiveness Property. Based on Raymond's algorithm, our algorithm exploits the request-reply messages exchanged by processes to get access to one of the k units of the shared resource in order to dynamically detect failures and adapt the algorithm to tolerate them. This work was published in [27] .

Recently we started to investigate two communication abstractions in asynchronous systems under various class of faults. The first abstraction deals with synchronizing logical clocks of neighboring nodes also known as unisson. We study the FTSS (fault tolerant and self-stabilizing) version of the problem in asynchronous settings. We addressed both the crash and Byzantine faults in [39] . The major contribution of our work steams in exploring for the first time the limits of FTSS unisson in asynchronous setting exploring both the impossibility and possibility results.

The second abstraction addresses the FTSS coloring of undirected networks. Coloring has a direct application in the implementation of TDMA communication which is one of the most efficient collision free communication primitives for adhoc networks. In [23] we propose some impossibility results and a deterministic solution that work under restricted schedulers. We extend the study in [22] by proposing probabilistic solutions for asynchronous networks.

Dynamic systems

In this context we are interested in designing building blocks for distributed applications such as: failure detectors, adequate communication primitives (publish/subscribe) and overlays. Moreover, we are interested in solving fundamental problems such as leader election, membership and naming.


Logo Inria