Netmap enables you to visualize a network with a vector mesh representation. You can place things like routers, terminals and hubs on the map and connect them with different links. You can also verify the operation of a complete network with a single click.
http://kempele.fi/~skyostil/projects/netmap-1.0.zip
http://kempele.fi/~skyostil/projects/netmap-1.0.zip