As the world makes a move towards new technologies that promise decentralization, many view the Bitcoin network as the most revolutionary form of this type of technology. However, while the final product looks pretty good, it is important to understand the details about it, particularly what is it that allows it to remain decentralized. The answer is simple — it uses a globally distributed network of computers, also known as nodes.
If that were it, the answer would truly be quite simple. Unfortunately, however, there are multiple types of nodes, with each of them having its own ‘job' to do. Only with all of them working together can the Bitcoin network operate as it is supposed to. So, let's see how many different node types there are, and how each of them contributes to the network.
Bitcoin network's nodes
Before we start listing the nodes themselves, let's first cover a few things and ensure that everyone is on the same page.
As mentioned earlier, a node is pretty much just a piece of computer equipment that is connected to a larger network. Nodes can come in many different shapes and sizes, similarly to how different devices in your home can be used for browsing the web. You can access the internet with your phone, tablet, a laptop, your desktop, and many other additional devices that are connected to the web as well, such as your router, a wireless IP camera, and alike.
Now, in case of the blockchain — Bitcoin's blockchain — there are four different types of nodes. That includes mining nodes, full nodes, super nodes, and light nodes. Mining nodes are quite different from other types, which have a relatively similar function. However, all of them are necessary, and they all work together to make the network function.
Simply put, mining nodes are nodes that are responsible for producing blocks that make up the blockchain. In the process called ‘mining,' network participants can then confirm which blocks are filled with valid transactions which should be added to the chain.
Mining Bitcoin uses a lot of energy these days, and the process is becoming more and more complex as the number of miners grows. This is why a large number of miners uses application specific integrated devices (ASICs) in order to mine Bitcoin.
To be precise, mining nodes do not maintain the actual blockchain. Instead, their job is simply to create blocks and add them to the chain. After that, the validation is done by another type of node, called a full node.
Full nodes are the second type of nodes, and their job is to hold the copies of the entire blockchain. Their role is extremely important for the network, as they need to be able to serve as a way of confirming the history of transactions that have occurred in the past.
Full nodes can validate all of the transactions that ever occurred, including the first block that was ever created. However, they need to be able to hold massive amounts of data, as the entire blockchain ‘weighs' around 200GB. According to some estimates, the Bitcoin network contains around 10,000 full nodes.
They are also the reason that the network can remain decentralized, as there are 10,000 computers out there, all of which contain the copy of the blockchain. If someone wanted to change something, they would have to hack all of these devices and make the change on all of them, which is hardly possible. As a result, the network can remain unsupervised by any type of centralized authority which would have full control over it.
Super nodes do a similar thing as full nodes, only their number of incoming and outcoming connections is different. They also work around the clock in order to help other full nodes connect to one another. By doing this, they can also increase the speed of the network. In other words, they serve as information relays which can ensure that every full node has the proper copy of the transaction history.
Finally, there are light nodes, also known as thin nodes. Their job is similar to that of full nodes as well, but they do not hold the entire copy of the transaction history. Instead, they only hold a portion of it, which makes them much lighter.
The portion that they hold usually includes the data regarding the previously mined block, including the time of mining, a unique identifying number, and other details. They do not need to be particularly powerful, and they are much cheaper to obtain and maintain.
In addition, light nodes can also dismiss a false blockchain if one of the full nodes gets hacked and tries to overwrite the transaction history.