Farcry: using mobility to support ad hoc networks

Mobile ad hoc networks (MANETs) are formed by using meshes of mobile devices that communicate wirelessly and act as repeaters. This can extend the range of wireless networks dynamically, since the network extends out beyond a central point, using each node in the network as a repeater. In this situation, mobility in MANETs is usually seen as a problem, in that systems need to be reconfigured when nodes move. Farcry uses mobility to overcome one of the key problems MANETs have to address: partitioning of the network into separate parts that cannot communicate. Breaks in the network can be patched by using mobile nodes to carry information between segmented networks. These networks are much slower than existing networks, but information can be routed where previously impossible.

MANET with nodes repeating information


Partitioned network


Using mobility to copy data around the network

Farcry works on a PDA copying messages from other PDAs it can see. As the user moves with their PDA they carry the messages to other remote PDAs. In our demos of this technology, we have used FarCry to disseminate MP3 files across a network of friends. As the files move, the path they take is put into the MP3's ID3 tag. This uses the geographical clustering of interests to record and control distribution.

In a second demo, Internet access can be provided at a distance by moving caches of pages held in individuals PDAs. RSS feeds are copied and passed between separated MANETS.

The Visual Studio 2005 solution containing the source code for FarCry may be downloaded here.