Hi!
I know this question is related to Polygon but I would like to have the Ethereum community’s point of view. After all, Polygon is a scalability solution for Ethereum and each one is making the other one better.
When I read about Polygon, half of the time, it is described as a Layer 2 solution. However, upon closer examination, it appears that technically, it functions as a sidechain.
I understand the distinction between Layer 2 and sidechain at a high level: Layer 2 security relies on Ethereum, whereas a sidechain is a completely independant chain that manages its own security with its own set of validators and consensus.
Though, I don´t really understand:
- what makes people think Polygon is a Layer 2. I also could ask “What part of Polygon architecture follows the Layer 2 pattern?” ;
- what makes actually Polygon a sidechain. I also could ask “What part of Polygon architecture follows the sidechain pattern?”.
I hope my questions are clear.
Thank your for reading and sharing your thoughts / explanations!
Polygon PoS is a side chain, but it calls itself a “commit chain” because it publishes checkpoints to Ethereum L1.
There is a pre-PIP proposal to change it to a zkEVM Validium. A Validium publishes validity proofs, like a rollup, but unlike a rollup it does not publish transaction data, but handles data availability (DA) itself.
Note the transaction data for rollups will only be kept around for a while with 4844 (in next Ethereum hardfork early 2024) and then purged - long enough for a fraud proof for optimistic chains.
This is meant to be a chain using validity proofs not fraud proofs. I am a little shaky as to where the trade off is in keeping the DA off the Ethereum L1 - lower cost vs? Need to read Vitalik’s paper on that again 😅