Tutorial Abstract Virtual Infrastructure

Abstract

Ad-hoc and mobile sensor networks are chaotic in nature. The goal of the tutorial is to present several techniques to form virtual infrastructure for such mobile ad-hoc networks. Different approaches (some of which are inherently self-stabilizing [2,3]) will be presented:

∙ The use of randomization to overcome the random nature of the network. In particular the use of random walks to obtain a middleware that supports group communication abstractions [11].

∙ The use of directed antennas to define ad-hoc virtual infrastructure. The directed antennas are used to define virtual tilling of geographic regions. The tilling definition serves as a backbone for communication procedures [7].

∙ The use of GPS service to define a static tilling of a geographic region. Each tile resembles a (base station free) cell in a cellular network. The mobile hosts that happen to be present at a cell implement the base station function. Whenever a mobile host arrives to a populated cell, it copies the state of the virtual base station, whenever the mobile host leaves the cell it erases the virtual state. Thus each tile is in fact a virtual automaton that may implement a router or home location server [1,4,8,9].

∙ One can imagine a virtual automaton deciding to move to a non mobile-host-deserted location to make sure it survives, or even move in order to collect information [5,6].

∙ Implementation of a virtual automaton by the moving hosts requires an investigation of security issues. One would like to avoid the possibility of an host to know or corrupt the state of the virtual automaton, reactive secret sharing techniques are suggested for this sake [10].

Partially supported by the Rita Altura Trust Chair in Computer Sciences.