Abstract
Blockchain is a type of distributed ledger. It is a chain of blocks. Each block contains a series of transactions. Each transaction
is for a value transfer or a smart contract execution. The main purpose of the blockchain system is to achieve consensus on
transaction sequence without a controller. The transaction processing capability of the blockchain is influenced by the
propagation time of a block in the network -- the shorter the block propagation time, the better the transaction processing
capability of the blockchain system, and the easier that system can reach consensus. Ethereum is the second-generation
blockchain. It supports Turing complete smart contracts. Although many factors will affect the performance of the Ethereum
system, the planned future work of the project is to optimise the transaction/block broadcasting process in the Ethereum peer-to-peer network.