A method to enable a network or system to expand.
The goal is to improve efficiency and output without hurting the existing operations.
In blockchain, scaling often involved second layer protocols which are built on top of the main chain and designed to increase transaction throughput. These are typically sidechains or off-chain layers.
Some second layer solutions:
- Sharding
- Roll ups
- Blockchain interoperability
- State channels (payment channels)
The best example within cryptocurrency is the Lightning Network built to help scale Bitcoin. It is a payment system designed to help the decentralized network's efficiency by allowing multiple users to create a direct communication link.
Scaling can take place at any layer of the system.