LAYER 1
A Layer-1 blockchain (also known as the parent chain or root chain) is typically a name used to describe a main blockchain network protocol such as Ethereum or Bitcoin. Layer-1 blockchains are simply the main network that a Layer-2 scaling solution attaches to in order to improve the scalability and transaction throughput of the main chain, or Layer 1.
LAYER 2
Layer 2 refers to a secondary framework or protocol that is built on top of an existing blockchain system. Layer 1 blockchains face the problems of scaling, speed, volume of transaction processing power, high has fees. All these Layer 2 blockchains are created to solve yet ensuring the security of the chain.
Layer 2 protocols are specifically designed to integrate with the underlying blockchain to improve the transaction throughput. They rely on the consensus mechanism and security of the main chain.
Layer 2 Scaling Solutions:
There are two main dimensions where Layer 2 scaling solutions differ from each other;
Transaction Execution: This strategy deals with how transactions are run, where they are run, what the trust environments are, what the security and decentralization environments are, etc.
Data Availability: This strategy deals with whether or not the Layer 2 solution makes their transaction data available on the main Layer 1 chain or not.
Channels Through Which These Scaling Solutions Are Deployed:
Transaction Execution:
A. State Channels:
State channels were the first widespread scaling approach for blockchains. State channels are used when two or more users want to do a bunch of transactions in a trusted setting without paying gas every single time. In a single and simple layman word: It’s a method of performing several transactions that could’ve cost alot of gas if done on on-chain(Layer 1) to be done off-chain(Layer 2) and sent to on-chain(Layer 1) for confirmation thereby reducing drastically gas fees.
Example: Imagine developing a chess game on Ethereum where you have 3 players to bet and the winner will go with the rewards, surely alot of transactions will be carried which will cost alot because each time a player plays gas will be charged for that transaction. Thereby avoiding this extreme gas charge State Channel is opened anytime the chess game is to be played and all time will be played off-chain as the state is opened and after the completion of the game the state will be closed and sent to on-chain (Layer 1) thereby causing the whole transaction to just pay for winning or taking reward. Perfectly in short of how State Channel is Deployed.
NB: State Channel is a game played on solely TRUST.