Characterizing the interaction between routing and MAC protocols in ad-hoc networks

We empirically study the effect of mobility and interaction between various input parameters on the performance of protocols designed for wireless ad-hoc networks. An important objective is to study the interaction of the routing and MAC layer protocols under different mobility parameters. We use three basic mobility models: grid mobility model, random waypoint model, and exponential correlated random model. The performance of protocols is measured in terms of various quality of service measures including (i) latency, (ii) throughput, (iii) number of packets received and (iv) long term fairness. Three different commonly studied routing protocols are used: AODV, DSR and LAR scheme 1. Similarly three well known MAC protocols are used: MACA, 802.11 and CSMA.Our main contribution is simulation based experiments coupled with emph rigorous statistical analysis to characterize the emph interaction between the above stated parameters. Such methods allow us to analyze complicated experiments with large input space in a systematic manner. From our results, we conclude the following: No single MAC or routing protocol dominated the other protocols in their class. More interestingly, no MAC/routing protocol combination was better than other combinations over all mobility models and response variables.In general, it is not meaningful to speak about a MAC or a routing protocol in isolation. Presence of interaction leads to trade-offs between the amount of control packets generated by each layer. The results raise the possibility of improving the performance of a particular MAC layer protocol by using a cleverly designed routing protocol or vice-versa..