Hot/cold routing in mobile ad hoc networks

In mobile ad-hoc networks, many routing algorithms rely on some form of flooding to accomplish the route discovery process. Flooding, however, consumes many valuable network resources, such as time, bandwidth and power. Most current routing schemes expire cached routes after a time to account for nodal movement. Expired routes are resources which, to this point, have been left untapped. The paper proposes a new route discovery method, called hot/cold routing, which directs broadcasts toward the destination node even in the absence of location information. The hot/cold routing scheme reduces the search space for the destination node by implementing an expired route cache that is utilized by each node in the network. Routes are added to the expired route cache as they expire from the active route cache and remain there until some time interval has passed or a new route has been discovered. Since these expired routes can provide valuable insight into finding new routes, hot/cold routing uses them to direct broadcasts toward the destination node. Hot/cold routing can save a significant quantity of valuable network resources because only nodes near the optimal path rebroadcast route requests.