The Impact of Node Density and Buffer Size on DTN Routing Protocols with Energy Efficiency

Delay Tolerant Network (DTN) architecture comprises of portable devices known as nodes, considered a resource-limited networking system. These nodes in DTN utilize the ‘Store Carry and Forward’ approach to route data since the end to end connections are absent here due to a large number of constant intermittent connectivity. The energy quantity of nodes is restricted because limited-lifetime rechargeable batteries drive them. Accordingly, energy is an essential resource in DTN scenarios. For efficient network performance, including proper energy usage, nodes need to expense a minimum amount of energy. For this reason, it is essential to select an energy-efficient forwarding strategy and exhibit excellent performance among existent forwarding approaches in the DTN environment for routing messages effectively. In this paper, we have studied the energy efficiency of conventional DTN routing protocols: Epidemic, Spray and Wait, Spray and Focus, MaxProp, and PRoPHET on the impact of varying both buffer size and node density. We analyzed their energy consumption and compared their performance based on five performance metrics: average remaining energy, delivery ratio, average delay, transmission cost, and average hop count, respectively. Using ONE simulator, we performed a simulation with varying node density (while buffer size is fixed) and varying buffer size (while node density is fixed). From the outcomes of simulation, we found that Spray and Wait are the most energy-efficient DTN routing protocols. On the contrary, Spray and Focus possessed as the best performer in terms of average hop count, average delay, delivery ratio and transmission cost among conventional DTN routing protocols.