First off, a node is an indispensable and fundamental component of the blockchain network, which is the decentralised ledger used for maintaining any cryptocurrency.
To break down the concept of a blockchain node, let’s look at it this way :
- A blockchain consists of numerous blocks of data.
- These blocks of data are stored on nodes that can be compared to small servers.
- On a blockchain, all the nodes are connected to each other and they continuously exchange the newest information on the blockchain with each other.
- This ensures all nodes are updated.
- The nodes actually store, spread and preserve the blockchain data, and thus it can be said that a blockchain exists on nodes.
- Nodes, therefore, are the framework of a blockchain.
- Now, nodes can be any kind of device, usually computers, laptops or servers.
To understand nodes better, it’s important to know some of the critical functions they perform :
- When a miner tries to add a new block of transactions to the blockchain, the node transmits information of the block to all the nodes on the network.
- The nodes can accept or reject the block on the basis of the block’s validity of signature and transactions.
- If a node accepts a new block of transactions, it saves and stores it on top of the rest of the blocks it already has stored.
- Nodes thus save and store blocks of transactions or transaction history.
- Nodes broadcast and disseminate this transaction history to other nodes, which may need to synchronize or update with the blockchain.
Now let’s take a look at the different types of nodes. There are broadly two types:
- Full nodes
- Lightweight nodes
There are also Miners’ nodes and Listening nodes among the most important nodes.
- Full nodes support and provide security to the network.
- These nodes download the complete history of a blockchain to observe and enforce its rules.
- They mainly maintain consensus between other nodes and ensure correctness and verification of the data on the blockchain by storing a copy of the blockchain.
- Lightweight nodes: These nodes establish connection between users outside the blockchain.
- A lightweight node is each user in the network, who needs to connect to a full node in order to synchronize to the current state of the network to be able to participate.
- Miners’ nodes These are nothing but the Bitcoin miners present throughout the world.
- These miners are called miners’ nodes.
- Once the nodes validate a transaction, it’s shown in a pending state until a specialized and solo node, known as a miner, or a group of miners called mining pool picks up the transaction.
- The miners compete to confirm the pending transactions.
- After being confirmed, the transaction is added to the blockchain and the recipient of the bitcoin transaction can send it to another user.
- Listening nodes These are also called supernodes.
- These nodes are publicly visible and accessible full nodes.
- These function as communication bridges by providing blockchain data to other nodes.