Performance Comparison of SPIN based Push-Pull Protocols

Multiple data-centric protocols - which can broadly be classified as push-pull, push-only, or pull-only - have been proposed in the literature. In this paper we present a framework to develop an insight into the characteristics of push-pull protocols. The performance of push-pull protocols is critically dependent on the timeout settings used to trigger failure recovery mechanisms. We perform a study of how to choose optimal timeouts to achieve best performance and use these timeouts to simulate and compare various push-pull protocols. Our starting point is a recently proposed SPIN-based protocol, called shortest-path minded SPIN (SPMS), in which meta-data negotiations take place prior to data exchange in order to minimize the number of data transmissions, thereby improving in both energy and delay compared to SPIN. We propose a redesign of SPMS, called SPMS-Rec, which reduces the energy expended in the event of failures by requiring intermediate relay nodes to try alternate routes. Our simulation results show that SPMS-Rec outperforms SPMS, and thus SPIN, yielding energy savings while reducing the delay when multiple nodes fail along a route. We further propose a modification to SPMS-Rec through request suppression which helps in reducing redundant data transmissions.