Ad hoc public wireless networks deal with transient traffic patterns. Sporadically evaluating the performance of ad hoc network routing protocols via simulation amid synthetic workloads lacks credibility. This is due to the scarce investigation of discontinuous routes originating from mobility or congestion [1]. In particular, simulations sometimes do not accentuate the costs of discovering routes. An effective ad hoc packet routing tactic should spawn less frequent route discovery than long-term communication to circumvent flooding a network.

Piggybacking, timestamping, and layered routing are valuable strategies for reducing overheads of protocols, improving the packet delivery ratio, and minimizing network congestion and interference. Setting the appropriate heartbeat frequency and the number of routes for piggybacking a reply message in high-mobility networks is nontrivial. The tradeoffs between the speed of topological change propagation and protocol overheads must be objectively weighed. The authors of this paper have developed a valuable hybrid backbone routing protocol (BRP) for both short- and long-term network traffic. The BRP piggybacks information on each route-discovery reply message to prefetch routes for multiple nodes, applies timestamps to route-cache entries, and dynamically modifies inter-backbone-node links using proactive local route adaptation and recovery without altering global caches of routes or dropping packets. The novel BRP applies a backbone topology to resourcefully improve route-!cache and frequency of route discovery.

The BRP was evaluated by using a collection of 200 randomly distributed nodes in an area of 1500-by-750 meters that was designed to eliminate the formation of chain-like backbones. Concurrent continuous bit rate traffic connections with varying durations at each connection were used to simulate the mobility of the short- and long-term traffic network loads. The performance of both small and large dynamic source routing protocols was assessed alongside two versions of the hierarchical protocol developed by the authors. Incredible results and recommendations came from the simulation experiments, including the capacity to improve broadcast efficiency by modifying control messages operating in promiscuous mode at specific network nodes, the importance of scaling the lifetime duration of traffic connections, and the substance of varying short-time connections at hot spots.