Mobile Agents for Dynamic Multi-Hop Networks

Here at the MIT Media Lab, Nelson Minar, Kwin Kramer, and Pattie Maes have been working on using mobile agents to route packets on dynamic, multi-hop networks (aka ad-hoc networks). Our work has connections to active networks and social insect paradigms. We are currently working to apply our research to build real, flexible, low power wireless networks for use inside buildings.

We have three papers and a demo:

Cooperating Mobile Agents for Mapping Networks (May 1998)
Our first paper on the topic. The simulated system is a bit unrealistic, but we have an interesting population diversity result.
Cooperating Mobile Agents for Dynamic Network Routing (December 1998)
A book chapter that describes more recent (and more realistic) results.
Tutorial: Mobile Software Agents for Dynamic Routing (March 1999)
An article in Mobile Computing and Communications Review that summarizes our results and presents some of our thinking on mobile agents and routing.
An applet demo
Shows the dynamics of one version of our simulator.

Simulated System Description

At right is a screenshot of our simulator. Nodes in the network are drawn as squares. Green lines between nodes indicate physical links; each node has a limited transceiver range, faintly visible as grey circles surrounding the yellow nodes. In our simulation these nodes are moving, so the physical links are constantly breaking and reforming as nodes move in and out of range with each other.

Blue circles represent routing agents travelling around the network, red circles are message agents. The goal of the routing agents is to update the routing tables on each node so that message agents can find their way from any arbitrary node to one of the yellow "gateway" nodes. Nodes in white currently have a valid route to a gateway, nodes in grey do not.

As you can see, the three nodes in the upper left have no route to a gateway because they are physically out of range. Three nodes in the lower middle also do not have a valid route at the moment, because a link they were relying on has been broken. As the blue routing agents move to those nodes, their routing tables will be updated and they will turn white again.

If you want to see animation, we have an applet of an earlier system simulation.

  routing screenshot

Nelson Minar Created: December 3, 1998
<> Updated: November 30, 1999