The definition of a node may vary depending on the context used. For example, when it comes to computer networks or telecommunications networks, nodes may serve different purposes as they represent a redistribution point or a communication endpoint. Usually a node consists of a physical network device but there are some specific cases where virtual nodes are used.

Simply put, a network node is a point where a message can be generated, received or transmitted. Here we will discuss the different types of Bitcoin nodes which are: Full Nodes, Super Nodes, Miner Nodes, and SPV clients.


Bitcoin Nodes

Entering into the context of blockchains, which are designed as distributed systems, the network of computer nodes is what makes it possible to use Bitcoin as a decentralized digital currency that operates on a peer-to-peer system and is resistant to censorship by its design and does not require any other method to By mediating between one user and another user (regardless of the distance between them in the world).

Therefore, the blockchain nodes are responsible for acting as a connection point that may perform various functions. Any computer or device that connects to the Bitcoin interface can be considered a node in the sense that they communicate in some way with each other. These nodes are also able to transmit information about transactions and blocks within the distributed network of computers using Bitcoin's peer-to-peer protocol. However, each computer node is defined according to its own functions, so there are different types of Bitcoin nodes.


Full Nodes

Full nodes are what support and provide security for Bitcoin and are indispensable. These nodes are also referred to as full verification nodes because they intervene in the process of verifying transactions and blocks according to the system's consensus rules. Full nodes can also relay new transactions and blocks to the blockchain.

Normally, a full node uploads a copy of the Bitcoin blockchain with every block and transaction but this is not a requirement to be considered a full node (a reduced version of the blockchain can be used instead).


A full Bitcoin node can be created through different software applications, but the most common and popular is Bitcoin Core.

These are the minimum requirements to run a full node for Bitcoin Core:

  • A computer or laptop with the latest version of Windows, Mac OS

  • 200 GB available disk space.

  • 2GB of memory (RAM).

  • High-speed internet with download speeds of at least 50 kb/s.

  • An open connection or a connection with high load limits. Full hotspots may have upload usage of 200GB per month or more and download usage of up to 20GB per month. You will also need to download about 200GB when you first start up the full node.

  • The full node should be running at least 6 hours a day. It is also better to work continuously 24/7.


Many volunteer organizations and users run Bitcoin full nodes as a way to help the Bitcoin system. Currently there are approximately 9,700 public nodes running on the Bitcoin network. Note that this number only includes public nodes, which refers to visible Bitcoin nodes that can be seen and accessed (also known as listening nodes).

Besides public nodes, there are many other hidden nodes that are not visible (non-listening nodes). These nodes typically operate behind a firewall through hidden protocols such as Tor, meaning they are configured not to listen in on communications.


Listening Nodes - Super Nodes

Basically a listening node or super node is a complete node that is publicly visible. So that it communicates and provides information to any other node that decides to establish a connection between them. Hence, a supernode is essentially a redistribution point that may act as a data source and as a communication bridge.

A trusted supernode typically operates 24/7 and has multiple connections in place as it transmits the blockchain history and aggregate transactions to multiple touchpoints around the world. For this reason, a supernode may require more computational power and better Internet connectivity when compared to hidden full nodes.


Miners’ Nodes

To be able to mine Bitcoin in the current competitive state, one has to invest in specialized mining hardware and software. These mining programs are not directly related to Bitcoin Core but are implemented in a similar way to trying to mine Bitcoin blocks. The miner may choose to work alone (solo miner) or in groups (pool miner).

While full nodes of individual miners use their own version of the blockchain, collective miners (mining pools) work together with each one contributing their own computing resources (hashpower).

In a mining pool  only the pool administrator is required to run a full node  which can be referred to as a full node for mining pool users.


Lightweight or SPV Clients

SPV clients (or lightweight clients) are lightweight clients that use the Bitcoin network but do not truly operate as a full node. Therefore, SPV clients do not contribute to the security of the network because they do not maintain a private copy of the blockchain and are not involved in the process of verifying and confirming transactions.

In short, SPV is the way a user can check whether some transactions have been added in the block or not, without having to download the entire block data. SPV clients therefore rely on information provided by other full nodes (super nodes). Light clients act as communications endpoints and are used by many cryptocurrency wallets.


Client vs Mining Nodes

It is important to note that the meaning of running a full node is not the same as running a full mining node. While miners have to invest in expensive mining hardware and software, anyone is capable of running a full validator node. Furthermore, before attempting to mine blocks, miners need to collect pending transactions that were previously accepted as valid by full nodes. Next, the miner creates a candidate block (with a set of transactions) and attempts to mine this block. If the miner can find a valid solution for this block, it broadcasts it to the network and other full nodes will validate the block. Therefore, consensus rules are defined and secured by the distributed network of validator nodes, not miners.



Conclusion

Bitcoin nodes communicate with each other through the Bitcoin P2P network protocol and by doing so, they ensure the integrity of the system. A node that misbehaves or tries to spread incorrect information is quickly identified by honest nodes and then disconnected from the network.

Despite the fact that running a full validator node does not provide financial rewards, it is highly recommended as it provides trust, security and privacy to users. Full nodes ensure that the rules are followed. The blockchain protects against attacks and fraudulent methods such as (double-spending) or (double spending). In addition, a full node does not need to trust others and allows the user to have full control over their funds.