A Fully Distributed Document Sharing System for Mobile Ad Hoc Networks (LaBRI RR-1395-06)

Many research projects have defined applications that are claimed to operate in a MANet environment. Consider for instance the notion of a distributed file system which is the concern of a large number of these applications. It appears that most of the proposed solutions require a central server that makes it possible to ensure data consistency, by storing copies of the data from time to time, and thus making it possible for all the mobile units of the system to get the most recent version of the data. This does not work in a real MANet environment, where the presence of a central server cannot be guaranteed. The applications that really work in a MANet context are those that do not require global consistency. In this paper we present an application that makes it possible to share a document among the mobile nodes of a MANet. One of the major originalities of our solution is to work in a real MANet environment. It makes it possible to modify shared data still ensuring consistency, without any central server. From a practical point of view, a document can be split into pieces (or blocks) and shared among a set of mobile devices; the blocks can be modified, split further, and the whole document can be locally rebuilt depending on how and when the different mobile units come across.