Assessing Effects of Overlay Networks on Latency in IoT Blockchain <Abstract> With various applications, the Internet of Things (IoT) has been transforming society, human lives, etc. However, the existing IoT faces several issues, including the lack of security, privacy, interoperability, etc. Blockchain has been emerging as a solution for such IoT issues. Accordingly, there is increasing interest in deploying IoT Blockchain systems, in which latency is one of the major concerns. This study aims to assess the impact of Erd?s-R?nyi overlay network configurations on an Ethereum-based IoT system, revealing significant implications for scalability performance considering two latency metrics: Transaction Oriented Latency (TOL) and Block Oriented Latency (BOL). We found that in the worst-case scenario, the average latency was four times greater in TOL and fifteen times higher in BOL compared to the best-case one. |