A node is a device on a blockchain network, that is essentially bedrock of the technology, allowing it to function and survive. Nodes are present across a widespread network to carry out different tasks. Let us examine the qualities of a node on a blockchain network.
A node could be many thing, an electronic device, computer, phone, printer, as long as it is connected to an internet and has an IP address. The function of a node is to support the network by keeping a copy of blockchain and maybe also process transactions. Nodes are arranged in form of binary trees. Every Cryptocurrency has its own node, keeping transaction record of that particular token.
Nodes are a separate part of the larger blockchain network. Because nodes deploy their computational power to store and validate transaction they get transaction fee and earn an incentive in the underlying cryptocurrency for doing so. The process is called mining or forging.
Processing transactions require astronomical amount resources i.e computational power thereby rendering average computers useless. Professional miner invest extremely powerful computing devices called CPU(central processing unit) or GPU(graphics processing units) to meet the demand of processing power that is required to validate transactions and to earn rewards that are associated with it
Each node is linked to another node in blockchain which can either be communication endpoint or the point of communication distribution. Generally, each node is equal but some node has an extra function to support the network. For instance, each node will store the full copy of blockchain or validate transactions.
A full node downloads a complete copy of a blockchain and checks any new transactions coming in based on the consensus protocol utilized by that particular cryptocurrency or utility token. All nodes use the same consensus protocol to remain compatible with each other. It is the nodes on the network that confirm and validate transactions, putting them into blocks. Nodes always come to their own conclusion on whether a transaction is valid and should be added to a block with other transactions, irrespective of how other nodes act.