The term "node" is actively used in information technology. So, for example, for computer or telecommunication networks, this is either a redistribution point of information or an endpoint for communication. Almost always - a physical device, but in some cases, it is possible to use virtual ones.
In the context of cryptocurrency networks, the situation does not change much. A node is a point at which various messages are created, transmitted, or received. And depending on what each individual node mainly works on, they are further classified.
Bitcoin nodes and blockchain
This cryptocurrency network is positioned as a distributed P2P network consisting of separate peers. This guarantees high resistance to external influences and internal censorship.
Every computer that is connected to this network can be considered as a node. But despite the fact that all of them have the same rights a priori, they can perform different tasks. Here a lot depends not only on the goal of the owner but also on the specific parameters of the computer.
A machine that provides network security and supports its functioning. Сomplete and adequate copy of the entire blockchain is stored on them. And they are the one who is checking the conformity of the new information and ensuring that it logically and consistently comes from the existing information.
However, this is a rather difficult task, since it involves constant communication with all the machines in the network and obtaining any information about its changes. So, without meeting certain technical points, a computer cannot be considered a complete node. The following parameters must be observed:
- The latest version of the popular operating system - Windows, Mac OS X or Linux.
- 200 gigabytes of free disk space
- 2GB RAM
- Internet speed - at least 50 kB/s
- Unlimited connection, or connection with a very large limit
- Big working time. Minimum - 6 hours a day, but better - 24/7
Currently, about 9,700 such complete nodes are connected to the Bitcoin blockchain. However, during calculating, only publicly accessible nodes were taken into account - “Listening nodes”, which any other computer can contact at any time in order to get an adequate copy of the blockchain state. But there are also hidden nodes that work in exactly the same way but are not tracked during the search. They usually work either through some kind of Firewall or through anonymizers, such as Tor. And even despite the fact that it’s extremely difficult to “reach out” to them - they are the ones who are responsible for the stability of the entire system.
The optimal state of a full node. Other computers can contact them to obtain a complete and adequate copy of the information contained in the blockchain. This requires a good communication channel and stable performance. In addition, it is useful to have several permanent connections that provide additional bandwidth. And the computing power of such a super-node should be significant.
A machine on which installed software that allows you to mine bitcoins. These programs are embedded on top of Bitcoin Core and work in parallel with it. They can act both alone and as part of a group (miner pool). The second option is more effective since each machine contributes part of its computing power to the overall process, and then receives a percentage of the award equal to the percentage of the input power. Can also be full nodes. For example, the administrator of a mining pool is always a full node.
Lightweight or SPV nodes
The main feature is that they do not store all the information about the state of the blockchain network. But they can send requests to confirm or approve transactions. The protocol "Simplified Payment Verification" allows you to find out whether the data about the transaction were included in the block, without downloading this block. Obviously, such nodes directly depend on super nodes or full nodes. And this is exactly what most blockchain network users are.
The difference between a mining node and a full node
With sufficient processing power and suitable parameters, any super-node can simultaneously engage in mining and information verification. However, most users have to choose one thing. The problem is that mining takes up a lot of time and resources - at a minimum, you need to collect all the data about the recent transactions, and then - calculate the hash of the new block. There is no time left for subsequent validation and verification. Nevertheless, even though full nodes do not bring the same reward as miner nodes, someone should still keep them - otherwise, the whole system will become much more vulnerable to external attacks.
If all the nodes connected to the blockchain works according to the established rules, are beneficial and do not violate the basic protocols, the system works quickly and clearly. If the node delivers unverified or unreliable information, it cuts off from the global network.
It is following the general rules, as well as consensus algorithms, that leads to the fact that the network, consisting of various nodes with the same rights, continues to work. Yes, it has some drawbacks, but blockchain technologies are constantly being improved.