Nodes are computers that are connected and share information with each other to form a blockchain network. The union of these nodes is what forms the main base of the blockchain network, its fundamental axis, something like its spine.
In short, this is what the nodes do:
They check if a block of transactions is valid and accept or reject it.
They save and store blocks of transactions (storing the blockchain transaction history).
They transmit and extend this transaction history to other nodes that may need to synchronize with the blockchain (they must be updated in the transaction history).
Relationship of the nodes with the mining
For the safety of the blockchain network to be complete, the participation of the miners is not enough; there must also be nodes to help ensure that the rules that have been established for crypto-currency in particular are fully complied with. The nodes can store an important part of the information contained in that large ledger, reaching a maximum of 100GB of information.
It is good at this point to differentiate: nodes and mining are not the same thing although a computer that has been incorporated as a node to the blockchain could also be used for mining, but it would be exclusive of its other function. While the computers dedicated to PoW mining are constantly performing complex computer calculations, the nodes are there to guarantee the stability and security of the transactions performed by the miners, i.e. to ensure that the established rules are followed when adding new blocks to the chain, approving or not the transactions and they are not guaranteed a profit from their participation within the network.
Importance of nodes in blockchain security
In the digital world it is always very important to take all possible security measures, especially in this case where we are talking about digital money, that is, the handling of financial assets in a data network that, like every element on the web, runs the risk of being attacked and hacked by unscrupulous people.
The 51% attack that the blockchain network could have consists of a group of miners agreeing to control more than half of the network’s operations and thus make all decisions related to it. It is then as the real influence of the nodes in the operation of the blockchain network lies in the security that they bring to it and in the power of decision that they have on the approval or not of the transactions.
Types of nodes
In blockchain networks there are traditionally three types of nodes, which provide different functions within the network. These types of nodes are:
Broadcast nodes: they only emit transactions and receive the blockchain information from a third party. They follow what is dictated by the greatest mining power and are known as lightweight purses, widely used in mobile devices or simply by people who do not want to download the whole blockchain.
Complete nodes: When you install a complete node software like Bitcoin Core, besides having the most secure wallet, you’ll be downloading a copy of the blockchain and you’ll become one more node in the Bitcoin network. So, you’ll be issuing your transactions, propagating them to the rest of the network, and checking that the consensus rules are followed.
Mining nodes: miners must necessarily have a copy of the blockchain, in addition to running the mining software of their choice (BTCMiner, CGMiner). These nodes, besides being dedicated to mining bitcoins and therefore contributing to the creation of new blocks, also issue and propagate transactions.
What are the Masternodes?
Masternodes are a unique feature of some current blockchains. The masternodes are usually much more equipped than normal nodes. In addition to validating, saving and transmitting transactions, sometimes masternodes also facilitate other events in the block chain depending on their nature, such as voting events, execution of protocol operations and compliance with the laws of the corresponding block chain. The masternodes are usually always online (24/7) and provide much more memory than normal nodes. Because hosting a masternode generally requires many more resources (electricity, uptime, maintenance, storage space, memory), hosting generally provides a payment in the form of interest.
However, given the peculiarity of masternodes, not just anyone can run one. The power to control a masternode can be abused, and therefore requires the host to deposit a minimum amount (often quite large) of crypto currency as collateral. This guarantee is taken hostage when the masternode host violates the rules of the block chain. The interest rate a masternode host receives is calculated on its security deposit. On this retained money, depends the profit of the owner of the masternode, which is measured by a percentage of all transactions and operations handled by the set of masternodes in question. Projects like DASH and Ethereum, have in their structure the use and creation of masternodes.
I appreciate your contribution to encourage my articles