Types of Nodes - Crypto Ledgers

#BlockchainNodes

In the previous article , you learned about the recordkeeping in the bitcoin blockchain system. You saw how bitcoin uses UTXO’s for transactions and stores the UTXO’s obtained by a node at a given point of time and not the balance of each node. In this section, you will learn about the various types of nodes in the bitcoin blockchain network. Before going into the types of node, let’s take a time instance in the bitcoin blockchain network and analyze how transaction pool works,

Video1

In?blockchain at a given point of time, it is not necessary for all the nodes to have the same transactions in their transaction pool. There could be various reasons for this to happen such as network latency, broken connection, less computational power etc. Bitcoin blockchain also defines the frequency at which blocks should be created inside the network which is set to 10 minutes in the current Bitcoin system.

Now let’s analyze the roles of nodes in the network.

video 2

There are three types of nodes in the bitcoin blockchain network:

1. Miner nodes:?They create the blocks in the network
2. Full nodes:?They store the details of all the blocks in the network
3. SPV nodes:?They are nodes that store only the partial details of the blocks in the network

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Note: Questions like what are these partial details, what are complete details shall be answered shortly in upcoming videos. So please be patient! We shall address everything.

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You will understand these roles better in the upcoming videos. Now, let's see how the blocks are created by the miner in the upcoming video.

video3

The miner node takes the unconfirmed transactions in the mining pool and creates a block. Once a block is created, it gets flooded across the network using the gossip protocol. All the nodes receive the block and first validate the block if the block passes the validation they add it to their respective blockchain otherwise not. To understand the validation of block, let’s first dive into the contents of the block in the next section.

Types of Nodes

Suppose you create a blockchain network for your company. Now, you hire an external third party agent to perform some data validation tasks. There is no need to share the entire network data with the third party. Which type of node will the third party be in the network?

Mining Node

Full Node

SPV Node

? Correct

Feedback:

SPV nodes store only partial data and are used mainly for validation purposes. The third party fits exactly into the description and hence it should be an SPV node.

Your answer is Correct.

Block Anatomy

So far you have learnt about the architecture of the bitcoin blockchain network and the types of nodes that exist in the network. However, we are yet to discuss what comprises the blockchain, i.e., Blocks. Blocks are the fundamental components of the blockchain. The word "block" is an interesting way to think about the information it stores; but what a block actually is, might be a little different than what you expect. In this segment, we'll discuss what blocks are, and the various elements that are included in the block.

video

A blocks header is comprised of the following components:

• Merkle root?- aggregation of all the hash values of the transactions into a single hash value.
• Timestamp?- Timestamp of the block creation time.
• Nonce?- Random Value that is altered/updated to try different permutations to achieve the required difficulty level. You will learn more about this in the upcoming section.
• Transaction counter -?Count of the?number of transactions?in a block.

Contents of a Block

Blockchain is a chain of blocks wherein all the blocks are ordered according to the time at which they were created. Which of the following fields of block could be used in this case?

Nonce

Timestamp

? Correct

Feedback:

Yes, since the timestamp stores the block creation time it will be used to order the blocks in the blockchain.

Transaction Counter