Cascade: The First Interchain SVM

Cascade features an innovative new rollup architecture design.
There are two core ideas that form the basis of Cascade:
  1. 1.
    Optimistic rollups
  2. 2.
    Sovereign rollups
Cascade is an optimistic SVM rollup using the Eclipse sovereign settlement layer. For a more detailed technical explanation of how the Eclipse chains work, refer to the Eclipse developer docs.
In this article, we'll explain how optimistic rollups and sovereign rollups on a high level.

Blockchain Architecture Fundamentals

A typical blockchain (or "rollup") engages in the following functions:
  • Execution: computing the state of the blockchain after ingesting transactions
  • Settlement (for rollups): verifying the correctness of execution and bridging
  • Consensus & data availability: establishing the ordering of transactions

Optimistic Rollups

At a high level, rollups execute transactions and separately must "settle" that execution to verify that the execution was correct.
There are two types of settlement: optimistic or zero-knowledge. An optimistic rollup periodically posts the result of transactions to some settlement layer along with a bounty. If a challenger correctly asserts that the execution was invalid, the challenger receives some (or all) of the bounty. The settlement layer must have some method of determining whether a challenge is correct or not.

Sovereign Rollups

A "smart contract rollup" like Optimism or Arbitrum settles to some set of smart contracts on a Layer 1 blockchain like Ethereum. By contrast, "sovereign rollups" don't require such smart contracts to perform settlement. Instead, sovereign rollups like the Eclipse settlement layer circulate fraud proofs directly to light clients. If the majority of Eclipse becomes dishonest, these circulated fraud proofs ensure that an honest minority can still maintain the integrity of the chain.

Block Production

Cascade block production is primarily managed by a single party, called the "sequencer," which helps the network by providing the following services:
  • Providing transaction confirmations and state updates
  • Constructing and executing rollup blocks
  • Posting rollup blocks to the settlement layer, where they are passed to the consensus layer
For the moment, the Eclipse team runs the primary block producer. Over time, there are plans to further decentralize the sequencer role. In order to further increase scalability parameters, there are plans to integrate Celestia in the near future to serve as a modular data availability layer.