Impact of Node Churn in the Bitcoin Network with Compact Blocks

Abstract

Compact block protocol aims to reduce bandwidth usage and, possibly, latency in the Bitcoin network. In this work, we present an analytical model to evaluate the impact of churning nodes on the Bitcoin network when the compact block protocol is used. We use a Continuous Time Markov Chain to model wake-up and sleeping behavior of each node in the network. We also calculate synchronization time, including transaction deficit recovery, when a node rejoins the network. When a node is absent from the network, it misses blocks mined during its absence but also some of the transactions which may be omitted from the subsequent compact blocks. Our results indicate that synchronization time takes more than a minute when node is away from the network for several hours. Moreover, the majority of synchronization time is spent on block verification and transaction deficit recovery.