Under the Hood of the Ethereum Gossip Protocol

Blockchain protocols’ primary security goal is consensus: one version of the global ledger that everyone in the network agrees on. Their proofs of security depend on assumptions on how well their peer-to-peer (P2P) overlay networks operate. Yet, surprisingly, little is understood about what factors influence the P2P network properties. In this work, we extensively study the Ethereum P2P network’s connectivity and its block propagation mechanism. We gather data on the Ethereum network by running the official Ethereum client, geth, modified to run as a “super peer” with many neighbors. We run this client in North America for over seven months, as well as shorter runs with multiple vantages around the world. Our results expose an incredible amount of churn, and a surprisingly small number of peers who are actually useful (that is, who propagate new blocks). We also find that a node’s location has a significant impact on when it hears about blocks, and that the precise behavior of this has changed over time (e.g., nodes in the US have become less likely to hear about new blocks first). Finally, we find prune blocks propagate faster than uncles.