A device in a decentralized network that assumes the role of supporting the protocol by maintaining a copy of the blockchain and, in some cases, processing transactions is referred to as a node. The distribution across many nodes makes a network decentralized.
A node can be any active electronic device, including a computer, phone, or even a printer, as long as it is connected to the internet and has an IP address. Depending on their function in the network, nodes have specific names and are programmed to carry out transactions based on a particular consensus mechanism.
Nodes as building blocks for decentralised blockchains
Essentially, nodes accept or reject proposals or transactions. Authenticated transactions are added to the blockchain, copied and distributed throughout the network. Unauthorised proposals are rejected and not added to the blockchain. New blocks are processed live, and all copies of the ledger are updated immediately. Nodes act as the storage containers of a blockchain, interacting with it whenever a user retrieves information. They remain fully transparent and accessible to anyone.
Nodes play a crucial role in decentralised blockchains, serving to validate and maintain the integrity and accessibility of the decentralised ledger. They form the backbone of decentralised systems, with each node containing a copy of the blockchain. The more nodes involved in a network, the better the system is protected against single points of failure. While a single node can potentially run an entire blockchain, it is vulnerable to such single points of failure. These could include power outages, hacking or system malfunctions. The presence of more complete nodes increases the blockchain's resilience to such disasters and makes it more difficult for a corrupt party to infiltrate the system, as seen in the 51% attack scenario on bitcoin.
In practice, nodes, sometimes referred to as "peers", fulfil different roles. Primarily, they validate transactions by verifying their accuracy and legitimacy using consensus algorithms such as Proof-of-Work (PoW) or Proof-of-Stake (PoS). The collective synergy of nodes, which vary in size and influence depending on the blockchain architecture, ensures the network's security, transparency and immutability.
Types of Nodes:
- Full Node
Manages all transaction records in the blockchain and serves as the "servers" of the blockchain. - Pruned Node
Similar to a full node, but with a storage space limit, retaining data from a specific number of blocks. - Mining Node
Used for Proof of Work consensus mechanisms, validating transactions and receiving compensation for the work. - Staking Node
Used in Proof of Stake consensus mechanisms, similar to mining nodes, validating transactions and receiving compensation for their work.
