# Sovereign Rollups - A Brief Intro

By [Aditi](https://paragraph.com/@adeets) · 2022-07-23

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In order to fully understand what a sovereign rollup is, we’ll need to first understand the different pieces of a blockchain:

1.  Data Availability and Consensus - makes sure data is available and that there is an agreed upon ordering of transactions. Example: [Celestia](https://celestia.org/)
    
2.  Settlement - writes transaction data to the DA layer while publishing new state to the settlement layer. Settlement layers maintain state roots and is a place for dispute resolution and proof verification to take place
    
3.  Execution - processing transactions. Example: [Fuel](https://fuel.network/)
    

![The modular blockchain stack. ](https://storage.googleapis.com/papyrus_images/ceceb73d54dcd42206b4a98af409ab1bab78086a859ec159e11053f17880d43e.png)

The modular blockchain stack.

Monolithic chains handle all three functions in one architecture. The modular stack scales **horizontally** by splitting up the three functions into different layers.

A sovereign rollup is a rollup that has the scalability and security of a rollup but the sovereignty of an L1. A sovereign rollup does not need a smart contract layer. Instead, every transaction is published to the data availability layer and settled in another layer.

Benefits of Sovereign Rollups
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*   Sovereign rollups can fork independently of the data/consensus layer. So sovereign rollups define their fork choice rules independent of the data/consensus layer.
    
*   Most rollups today do not have the ability to define their own rules for forking.
    
    *   Settling to a monolithic L1 means that the L1 innately decides which block gets added to the rollup chain. This makes forking very difficult without the L1 initiating the fork itself.
        
*   Proof verification happens on the p2p network. Instead of validating proofs on the L1, proofs will be distributed among nodes.
    
    *   In the optimistic case, a fraud proof is only distributed in the p2p network when there is a dispute.
        
    *   In the zero knowledge case, a validity proof is distributed in the p2p network with each block.
        
*   Execution layers generally act the same.
    
    *   Execution layers _still_ execute transactions off-chain. However in the modular stack, execution layers will push transactions to the settlement layer.
        
*   Sovereign rollups can take advantage of the trust-minimized nature of settlement layers where tokens can easily be transferred between rollups and the settlement layer.
    

Settlement Rollups
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Settlement rollups are similar to sovereign rollups except it can have execution layers on top of it. Settlement rollups **are still considered** sovereign rollups because they can fork at will, but their purpose is solely to act as a settlement layer for other execution environments.

In an app-chain/app-rollup world, settlement layers can be optimized or restrained such that execution layers powering applications are first class citizens.

Further Reading
---------------

*   [Rollups as Sovereign Chains](https://blog.celestia.org/sovereign-rollup-chains/)
    
*   [![User Avatar](https://storage.googleapis.com/papyrus_images/9ca77ed71bc2258254d8ab8b45760a07455ca30b1b0dc47a99ba55398bb3f8b4.jpg)](https://twitter.com/evansforbes)
    
    [zkFART 🦣](https://twitter.com/evansforbes)
    
    [@evansforbes](https://twitter.com/evansforbes)
    
    [![Twitter Logo](https://paragraph.com/editor/twitter/logo.png)](https://twitter.com/evansforbes/status/1540772513516511233)
    
    Sovereignty isn't just a meme. It's the ability to hardfork. It's the recognition that the most important layer in blockchains and society is social consensus.  
      
    It's the encoding of people > tokens. people > validators. people > governance.
    
     [![Like Icon](https://paragraph.com/editor/twitter/heart.png) 161](https://twitter.com/evansforbes/status/1540772513516511233)[
    
    2:02 PM • Jun 25, 2022
    
    ](https://twitter.com/evansforbes/status/1540772513516511233)
    
*   [Settlement Rollups: Celestia Forum](https://forum.celestia.org/t/an-open-modular-stack-for-evm-based-applications-using-celestia-evmos-and-cosmos/89)

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*Originally published on [Aditi](https://paragraph.com/@adeets/sovereign-rollups-a-brief-intro)*