Expanding Ring Search for Route Discovery in LOADng Routing Protocol

LOADng is an on-demand routing protocol, derived from AODV, simplified for use in lossy, low-power and constrained environments, where the ability for devices to communicate is a commodity to their primary function, and where therefore not only the communications channel offers limited capacity, but also the resources available to the device’s communications subsystem are limted. LOADng simplifies AODV in a number of ways, notably the route discovery process by removing intermediate/gratuitous Route Replies – sacrificing that functionality in order to attain smaller control messages and less router state and processing. Alas, this comes at an expense: in some situations, LOADng produces increased control traffic overhead (as compared to AODV), and more control messages transmissions means tapping into the device’s limited resources. This paper presents a simple mechanism by which to integrate Expanding Ring flooding into LOADng. The mechanism is described, and the result of simulation studies are presented, showing that both in scenarios with “point-to-point” (any-to-any) traffic and in scenarios with “multipoint-to-point” (all traffic sent to the same destination, as in a data acquisition sensor network) traffic, considerable savings in control traffic overhead can be achieved – without loss in data delivery ratios.