Users working in the cryptocurrency industry find it difficult to understand the concept of nodes. Noda, translated from Latin, means node. A node is a computer that operates in the Bitcoin network using the p2p protocol and allowing nodes to communicate with each other on the network and distribute information about transactions and blocks. All transactions are managed and coordinated according to the canons of a decentralized distributed network, which requires constant interaction between nodes. If a node goes down, it will fall off the network for some time and re-synchronization will be required to restore functionality. The more nodes operate in the system, the higher the scalability of the network is. It also increases the speed of transaction validation.

What is a node needed for? 

Since a network node is the basic element of the blockchain ecosystem, it cannot exist without it. Once a miner intends to add a new transaction block to the blockchain, he transfers the block to other nodes. They, in turn, can either accept or reject it. If the verification is successful, then the block is accepted. In other words, blockchain nodes are the backbone of the blockchain and it cannot function properly without them. Also, nodes that misuse or attempt to distribute incorrect information are quickly recognized by honest nodes and disconnected from the network.

The network node is the key factor that creates, receives, and transmits messages. The node monitors the consensus of the network, collects, records transaction data, and stores validated transactions. Each participant voluntarily provides his own hardware to support the blockchain and is not paid for these services. To become a node, the user needs to install special software designed for a particular cryptocurrency. A full node performs routing, base populating, and global blockchain support functions.

Further, the definition of a node can vary greatly depending on the context used. When it comes to computer or telecommunications networks, nodes can offer different services, acting either as a redistribution point or as a communication endpoint. After all, they perform functions such as keeping full copies of the ledger and updating the data to the current version synchronized with other nodes. Usually, a node is a real unit of computing equipment, that is, a personal computer connected to the Internet network with a local wallet installed and synchronized with the blockchain. All network participants have absolutely identical copies of the distributed ledger. Besides, a node can also be virtual. There are also lightweight network nodes that do not have their own copy of the blockchain, as well as special nodes of other types. But all of them must be connected to the same peer-to-peer network to exchange information. 

There are several types of nodes: full node, light node, master node, supernode. First of all, full nodes are communication nodes that are completely independent of each other and store all the data in the blockchain. The peculiarity of such nodes can be referred to as they operate completely autonomously from each other and do not trust the decisions of other communication nodes. 

Light nodes are communication nodes that have less autonomy, compared to full ones. They store only transaction block headers in the network and are dependent on full nodes. Masternode is specially adapted full nodes, which act as a trusted communication node and represents a connection to the network cryptocurrency wallet with placed deposit. Then, supernodes are masternode functioning without a wallet and acting as an endpoint of cryptocurrency API.

However, nodes make the rules, not miners. Miners receive transactions validated by the nodes and create blocks that will also be checked by the node. Important to note, that the consensus rules are not determined by the miners; their job is to put the transaction into a block that the node considers correct. The stability of the blockchain depends on how the node works, and users must be especially careful to secure the network so that attackers cannot exploit the vulnerability of nodes.