Predicting the performance of geographic delay-tolerant routing

Performing large scale physical experiments to evaluate the packet delivery ratio, latency, and resource utilization in mobile ad hoc networks is a costly and difficult exercise. A more cost-effective method of performing trade-off studies in connection with protocol evaluations is simulation. However, simulations are often time consuming and require a detailed description of a given scenario´s mobility and topology. A more general approach for scalability and performance studies is the use of abstract models of behavior in networks of mobile nodes. This paper illustrates the power of such a model by illustrating the prediction capability of the Forward-Wait framework with respect to the routing performance of geographic delay-tolerant routing. The Forward-Wait mathematical framework describes packet movements as a sequence of alternating forwarding and waiting phases. Key input parameters to the Forward-Wait framework are distributions describing the forwarding and waiting phases, and the source destination distance. The paper shows how these distributions can be derived and used to predict the routing performance in different scenarios and a variety of network sizes.