Blockchain network

A peer to peer network that consists of a bunch of computers working on a blockchain.

A network can be public (anyone can participate like in the Ethereum blockchain), private (permissioned) or hybrid.

Types of nodes:

• Miner/Validator; Create new blocks by collecting transactions posted on the blockchain network, checking them, construct a new block and post that on the network. In many blockchains miner receive a reward for being the first one to construct a new block.
• Full node; Checking block validity using all transactions and blocks.
• Lightweight node; Checking chain integrity using only the block headers.

Private Networks

• You don't need mining crypto-currencies, validators have an interest in the blockchain integrity.
• Nodes are known the owners of the blockchain decide on the validator nodes.
• Development is directed by the owners of the blockchain.

Hyperledger is an initiative of the Linux Foundation to standardize blockchain development. Hyperledger Fabric is a framework for private blockchains.

Hyperledger Composer is a tool to create Fabric applications. It uses so called LoopBakcs that can communicate blockchain transaction back to an enterprise business system.