What is Node?

Node is what we call all the participants in the blockchain network. Technically, each node represents an individual computer or device connected to a blockchain network.

Node is crucial for blockchain’s decentralization. Since blockchain does not rely on any third party, peer-to-peer (P2P) needs to be implemented. That means each node needs to communicate with each other and help maintain the system including block verification, protocol validity, and security of the blockchain. 

Types of Blockchain Nodes

In a nutshell, nodes are divided into two types: Full Node and Light Node. Blockchain is open to the general public to act as both types of nodes by attaching computing devices to the system. Additionally, both types of nodes have sub-nodes.

1. Full Node - A node that stores all transactions that occur on the blockchain from the beginning to the present. Therefore, users have to invest in devices with a high capacity of memory cards and space. A full node can be divided into two types:

• Pruned Full Node
  This is a node that stores the latest transaction and some remaining data. This type of node saves the device’s hard disk space, eliminating the need for high-spec devices to connect to the blockchain. Users can find a device with 500 MB capacity to store some necessary information, while users who wish to provide a full node that stores all the history of the blockchain need up to 360 GB of space in their device.
  
  
• Archival Full Node
  Usually, when talking about Full Nodes, most people refer to this type of node. It is the node that stores all the data from the beginning. Users who want to be an archival full node need a device with large-capacity memory to support all blockchain data. For example, users who currently want to become an archival full node for Bitcoin will need a device with 360 GB of memory.
  
  An archival full node can also be further sub-categorized as ones that can add new blocks to the blockchain and ones that cannot.
  • Miners (Mining Node) - a full node that adds new blocks to the blockchain by using Proof of Work as its consensus protocol. To validate transactions, let’s say in Bitcoin blockchain, “miners” are required to solve cryptographic, or mathematical problems, using their computers.
    
    
  • Stakers (Staking Node) - a full node that adds new blocks to the blockchain by using Proof of Stake as its consensus protocol. Stakers are required to stake or hold the cryptocurrency in order to be eligible for the validator node selection.
    
    
  • Authority Node - this type of node can perform its tasks of transaction validation without anyone giving them permission. These nodes have been pre-selected to be validator nodes.  Most of them are organizations or companies with reputations and credibility. Consensus protocols that rely on pre-selected validator nodes are Proof of Authority, Delegated Proof of Stake, etc.
    
    
  • Master Node - Compared to other types of full nodes, master nodes themselves cannot add blocks to the blockchain. While miners or stakers are the ones writing blocks on the blockchain, the master node’s purpose is to keep a record of transactions and validate them. An added benefit, however, is that by running a master node, users not only secure the network but can also earn a share of the rewards for their services.

2. Light Node - another type of blockchain node that downloads only the headers of blocks and saves the remaining hard drive space for users.

• Lightweight Nodes (SPV or Simple Payment Verification)
  Lightweight nodes are used in day-to-day crypto operations and transactions. They communicate with the blockchain while relying on full nodes to provide them with the necessary information. As they don’t store a copy of all blockchain data, they only require the current status of the latest blocks, and broadcast transactions for processing.

Q&A

Q: Why should I run a full node?

A: Most of the time, people who run full nodes on the blockchain want more security and privacy than relying on other people's full nodes. Moreover, having more full nodes in their system reduces the risk of network attack (51% Attack).

Q: Are full nodes similar to master nodes?

A: Full nodes and master nodes have the same features. But if you want to earn money while hosting the nodes, you can choose to become a master node. Be noted that you should have a careful calculation of costs and incomes.

Q: Can I become a full node for Bitkub Chain?

A: Bitkub Chain uses Proof of Authority as our main consensus protocol. At the moment, we have 11 organizations and start-ups with a trustful reputation as our node validators. If your company or organization would like to be part of our nodes, please visit https://bitkubblockchain.com/contact for our contact details.

You can find more information with interesting graphics at Plearn-D KUB EP.3: Node.

Reference: https://nodes.com/#masternodes