Wireless ad hoc routing protocols must employ accurate and rapid link failure detection mechanisms in order to maintain valid multihop routes and provide high data delivery rates. Hello-based failure detection is the predominant failure detection mechanism due to its ease of implementation. Despite its prevalence, no analytical work has been carried out to better understand its fundamental behavior. In this paper, we study the performance of hello-based link failure detection via analysis and experimentation. Our analytical results, which are validated by experimental results, show the existence of optimal hello beaconing parameters which depend on network conditions such as traffic load, link failure rate and hello delivery rate. These results can be applied in real-world network deployments for obtaining the optimal hello beaconing parameters that can provide the highest data delivery rate.