A blockchain node is a computer participating in a peer-to-peer network. A client is the software implementation that lets the computer understand and enforce protocol rules.
What you'll understand
- A full node independently checks blocks and transactions according to the rules implemented by its software.
- Light clients reduce resource requirements by verifying a smaller amount of information or relying on cryptographic proofs and additional assumptions.
- Some blockchains encourage multiple independently developed clients.
- Nodes discover peers, relay transactions and exchange blocks over network protocols.
Full nodes
A full node independently checks blocks and transactions according to the rules implemented by its software. This reduces dependence on third-party data providers.
Full verification may require significant storage, bandwidth and processing resources depending on the network.
Light clients
Light clients reduce resource requirements by verifying a smaller amount of information or relying on cryptographic proofs and additional assumptions.
They can be useful on mobile or constrained devices, but their security model differs from full verification.
Multiple client implementations
Some blockchains encourage multiple independently developed clients. Client diversity can reduce the chance that one software bug affects the entire network in the same way.
It also creates coordination challenges during upgrades.
Peer-to-peer communication
Nodes discover peers, relay transactions and exchange blocks over network protocols. This communication layer is a core part of blockchain resilience.
The clearest way to understand this topic is to separate the protocol, the digital asset, the software interface and any third-party service. Each layer has different responsibilities, dependencies and risks.
