1. A method of determining a shortest path in a network comprising a plurality of nodes, the method comprising: broadcasting a path request message from the source node; and propagating the path request message through the network from node to node, wherein, on first receipt of the path request message at each node, a hop count and broadcast identifier are stored, wherein, when a path request message is received a second time at any node, it is only propagated if the new hop count is less than the stored hop count, wherein the destination node replies to the source node along the path with the lowest hop count to set up the shortest path, wherein the network is a mobile ad-hoc network operating distributed routing, using an ad-hoc on-demand resilient path protocol, and wherein at least one of the nodes in the first and second paths does not have a fixed geographical location.