Mastering Ethereum, 2nd Edition

Chapter 3. Ethereum Nodes

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Ethereum Nodes

An Ethereum node is a software application that implements the Ethereum specification and communicates over the peer-to-peer network with other Ethereum nodes.

Initially a node only has to run one single client to completely implement all the requirements to be part of the Ethereum ecosystem. On the 15th of September 2022 the hard fork The Merge happened, changing the consensus protocol from a Proof of Work based to Gasper, the new Proof of Stake based consensus protocol. This also led to the separation of concerns - consensus and execution - and the creation of a new type of Ethereum client: a consensus client.

And so, at the time of publication, an Ethereum node must run two pieces of software at the same time to be compatible with the latest spec, as shown in Figure 3-1:

Figure 3-1.