A node (node) is a point in the blockchain network, the main function of which is to distribute data between other nodes. This is necessary to transfer information within the blockchain while maintaining the decentralization effect. A node can be an intermediate link or the final recipient of data.
Technical features of nodes
A node is a computer (server) with an installed cryptocurrency wallet, which is synchronized with other similar computers. A link of such nodes forms a blockchain. Using such a network makes it possible to quickly distribute large data flows.
The operation of the node is ensured by the power of the server. Any device that can transmit information via the Internet is suitable for this. Also, special software is required for the operation of the node.
In most cases, node is used to perform 3 tasks:
Store and distribute information between nodes about transactions and the amount of funds in the wallets of network participants.
Monitor the implementation of network rules (PoS, PoW consensus algorithm, etc.).
Support the operation of distributed registries, which store information about transactions for the entire existence of the network.
Nodes cannot work without an Internet connection. An offline storage device is also not capable of performing the function of a node. But it becomes a full-fledged node if it is connected to the Internet.
Why are nodes needed?
To support stable operation of the blockchain, you need a network of servers that are synchronized with each other. The main value of such a network is to ensure the effect of decentralization without losing the speed of interaction of information arrays.
Considering that computer nodes are located in different countries and cities, even blocking the Internet in a particular region will not lead to the blocking of the blockchain. But if all the nodes are concentrated in the hands of one group of people, then they will be able to completely control the network, which can lead to limiting the effect of decentralization.
At the same time, decentralization is one of the key advantages of cryptocurrencies. To ensure this and obtain the effect of data distribution, the blockchain uses numerous insignificant nodes. They do not participate in mining, but store the entire transaction history. This prevents one limited group of people from taking control of the distributed ledger.
Users who have provided their computing power to ensure the operation of the blockchain receive a reward for this. This is how the project motivates people to connect their PCs to a distributed network.
Types of nodes
Blockchain nodes vary in function and purpose. Among them there are several standard types that are present in many blockchains. There are also additional node models that are used in individual networks with expanded functionality.
Full nodes
This is the very first version of the node that was originally created to run Bitcoin. Full nodes form the basis of the blockchain and are involved in completing transactions.
Such a node contains all the information about transactions and blocks from the moment the network was launched to the current time. When one user transfers coins, this operation is “seen” by all nodes and saved in their history.
Tens of thousands of full nodes can operate simultaneously on one blockchain. They all constantly exchange information with each other. To process such a large data stream, sufficient computing power is required.
If a user installs a full node on his PC for the first time, it must be synchronized, that is, download the entire blockchain. In the case of some blockchains, this takes up quite a lot of memory. For example, the Bitcoin blockchain size in November 2022 was 438 GB, and it may take several weeks to synchronize it.
If a node is disconnected from the network for some time, then when connected, it must re-synchronize, that is, download all the information that was generated during the period of its absence.
Full nodes have a certain set of options that distinguish them from other types of nodes on the network. One of the most important functions is to verify signatures (keys) to confirm transactions and blocks. If an error is detected, the node may reject the operation. The reasons may be different: incorrect formatting, algorithm errors, duplication, manipulation of records, etc.
Users who have a full network node can check incoming transfers themselves. If they wish, they also have the opportunity to participate in mining and receive a reward for it.
Light nodes
Light nodes do not contain complete information about the blockchain. Such a node stores only a record of the block to which it is connected. In most cases, such nodes do not operate continuously.
Typically, a lightweight node is software that connects to a full node and relays information from it to the user's computer - for example, information about the account balance, incoming and outgoing transactions. In fact, a light node uses a full node as a bridge to access the blockchain.
A lightweight node has the necessary set of functions to use cryptocurrency, without requiring large computing power or memory. Therefore, it can be run even on a mobile device. Typically, synchronization takes a matter of seconds.
Pruned full nodes
Such a node downloads the entire blockchain and synchronizes it only upon its first launch. Next, it automatically loads new blocks and deletes old ones when a certain amount of memory is reached. Typically, the user can set the node size in the settings, for example, 10 GB.
Mining nodes
The mining node is involved in the cryptocurrency mining process and is used only in blockchains based on the Proof of Work algorithm. It can be full or light.
To run such a node, the user must have powerful computing equipment:
central processing unit (CPU);
graphics processing unit (GPU);
application-specific integrated circuit (ASIC).
You will also need to install special software.
Thus, in the process of mining Bitcoin, it is necessary to solve complex mathematical problems. As a result of such calculations, the miner finds a unique code value - a hash, which serves as proof of the work performed.
Next, the miner sends the found hash to other nodes, which must check it for compliance with the task. If the verification is successful, the miner can add a new block and receive a reward for this.
Staking nodes
This is an analogue of mining nodes, which is used in blockchains with the Proof of Stake algorithm. Such a node is also needed to validate transactions and add new blocks, and it can also be full or lightweight.
In this case, the reward is awarded not for mathematical calculations, but for storing a certain amount of coins in the account. Accordingly, to launch a staking node you do not need to buy expensive equipment. All you need to do is configure the software correctly and top up your account.
Masternodes
A masternode is an analogue of a full node: it also stores all the information from the blockchain and is synchronized with it, but it also has additional functions. They are needed to ensure anonymity by splitting transactions and sending them between wallets.
The owner of a full node can receive a masternode if he fulfills the necessary conditions of the blockchain. Typically, the main requirement is to replenish and hold a certain number of coins in your account. It is also necessary to perform special server settings (they are different for different cryptocurrencies).
When a user makes an anonymous transaction, their coins are “shuffled” in the masternodes. This process can involve a different number of nodes, which are scattered throughout the world and selected randomly. The number of mixing rounds also varies - this can be set manually or automatically. As a result, it becomes impossible to trace the connection between the sender and the recipient.
Masternodes can operate on the Proof of Stake algorithm or a hybrid PoW/PoS consensus. To encourage users to create and manage masternodes, the system awards them a portion of the miners' commission. The size of the reward also varies between different blockchains.
The type of masternode that runs on the NEM (XEM) blockchain is called a supernode.
Lightning nodes
Lightning Network (LN) is a second-layer add-on for the Bitcoin blockchain, which is a network of user payment channels. This system employs special ultra-fast nodes that synchronize with each other and with the main blockchain.
Lightning nodes only verify transactions that are directly associated with them (unlike standard nodes, which verify all transactions on the blockchain). Thanks to this feature, maximum transaction processing speed is achieved.
Validators and oracles
These are additional functions that a node in a decentralized network may have:
A validator node is a device that verifies transactions and approves them. Such nodes can operate using different algorithms depending on the characteristics of the blockchain.
An oracle is a node that transmits information from external systems to the blockchain. An example of such data could be the current cost of currencies for an exchange service running on a blockchain.
An oracle script is needed to convert information into a form understandable for a smart contract. The validator then validates the data from the oracle along with all other information on the blockchain.
In this case, the signal from one oracle is verified by a large number of validators, which increases the overall security of the network.
Forks and changes in node functions
Any cryptocurrency project can be updated periodically. For updates to take effect network-wide, all nodes must accept them. Sometimes there may be disagreements in the developer and validator community regarding the implementation of certain updates, when one part of the nodes may accept them, while others may reject them. The process of introducing changes is called a fork.
There are two types of forks:
A soft fork is a soft change and improvement that does not contradict the basic settings of the blockchain. To accept them, the node owner needs to update the software. If only a portion of the nodes accept this update, the system will still continue to operate stably.
A hard fork involves significant changes to the blockchain. As a result of such an event, the types of network nodes may completely change. For example, in September 2022, the Ethereum cryptocurrency switched from the POS algorithm to POW. As a result, mining nodes disappeared and staking nodes with validator functions appeared.
If there is disagreement in the community about whether to accept a hard fork, the network splits into two incompatible blockchains. One of them retains the basic settings, and the second switches to new ones.
