We're delighted to announce the development of a new feature in the Hermez zk-rollup that improves inter-L2 communication for the whole rollup ecosystem.
Hermez will release the first version of the zk-rollup network in early 2021, including implementing a mechanism for Massive Migrations of L2 transactions for the first time.Why Massive Migrations Are a Game Changer
Most people are aware of the current usability problem of switching between L1 and L2 and the high gas fees usually attached to it.
As more and more L2 solutions are implemented for different use cases, this usability problem would worsen, as users will have to pay high fees when transferring tokens from one rollup to another or alternative L1 smart contracts. This scenario could create a lock-in situation for user funds, limiting the interest in L2 solutions.
Under the current paradigm, when Bob wants to move funds between L2 solutions, say RollupA to RollupB, he has to withdraw funds from RollupA to L1. Then, he'll deposit the funds from L1 to RollupB. Bob would have to pay twice for gas, so he might think it is not worth it.Introducing Massive Migrations
The solution to this problem is simple but complex to implement. Hermez implementation follows very closely the concepts introduced by Barry Whitehat.
With Massive Migrations (MM), users will be able to deal with external L1 Smart Contracts in the same way that they transfer tokens to another Layer 2 network user.
These L1 Smart Contracts will need to be registered in L2, and the users will need to know the L2 address to transfer funds to it.
The Hermez protocol will offer a way to group and extract a set of L2 transfers with the same Smart Contract L2 destination address.
The destination rollup smart contract then withdraws the aggregated amount of funds in L1 using the standard Hermez functions. Although it will need to pay the funds' withdrawal fees, it wi...