A node is a critical component of a blockchain network, consisting of any computer that runs the blockchain software and participates in the network. Nodes are responsible for maintaining a complete and up-to-date copy of the blockchain ledger, ensuring that the data is accurate and consistent across the entire network. Depending on their type, nodes can perform various functions, such as validating transactions and blocks, relaying information, and storing the entire history of the blockchain. Full nodes maintain a complete copy of the blockchain and validate transactions and blocks according to the network's consensus rules, contributing to the network's security and decentralization. Lightweight or SPV (Simplified Payment Verification) nodes, on the other hand, do not store the full blockchain but can verify transactions using simplified proofs. Nodes communicate with each other to propagate transaction data and ensure the network's robustness and reliability, making them essential to the decentralized nature of blockchain technology.
