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As the communication infrastructure of the blockchain system, the underlying peer-to-peer (P2P) network has a crucial impact on the efficiency and security of the upper-layer blockchain such as Bitcoin and Ethereum. However, current Ethereum blockchain explorers (e.g., the Etherscan) focus on the tracking of block and transaction records but omit the characterization of the underlying P2P network. This work presents the Ethereum Network Analyzer (Ethna), a tool that probes and analyzes the P2P network of the Ethereum blockchain. Unlike Bitcoin that adopts an unstructured P2P network, Ethereum relies on the Kademlia DHT to manage its P2P network. Therefore, the existing analyzing methods proposed for Bitcoin-like P2P networks are not applicable to Ethereum. In Ethna, we implement a novel method that can accurately measures the degrees of Ethereum nodes; moreover, we design an algorithm that derives the latency metrics of the message dissemination in the Ethereum network. We run Ethna on the Ethereum Mainnet and conduct extensive experiments to analyze the topological features of its P2P network. Our analysis shows that the Ethereum P2P network conforms to the smallworld property, and the degrees of nodes follow a power-law distribution that characterizes scale-free networks.

The fundamental tradeoff between transaction per second (TPS) and security in blockchain systems persists despite numerous prior attempts to boost TPS. To increase TPS without compromising security, we propose a bodyless block propagation (BBP) scheme for which the block body is not validated and transmitted during the block propagation process. Rather, the nodes in the blockchain network anticipate the transactions and their ordering in the next upcoming block so that these transactions can be pre-executed and pre-validated before the birth of the block. It is critical, however, all nodes have a consensus on the transaction content of the next block.This paper puts forth a transaction selection, ordering, and synchronization algorithm to drive the nodes to reach such a consensus. Yet, the coinbase address of the miner of the next block cannot be anticipated, and therefore transactions that depend on the coinbase address cannot be pre-executed and prevalidated. This paper further puts forth an algorithm to deal with such unresolvable transactions for an overall consistent and TPS-efficient scheme. With our scheme, most transactions do not need to be validated and transmitted during block propagation, ridding the dependence of propagation time on the number of transactions in the block, and making the system fully TPS scalable. Experimental results show that our protocol can reduce propagation time by 4x with respect to the current Ethereum blockchain, and its TPS performance is limited by the node hardware performance rather than block propagation.

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