Scaling a $500Bn+ Ecosystem: Layer 2 and Different Ethereum Scalability Options and Their Present Answer Panorama



By Andreas Freund, EEA Mainnet Curiosity Group Member

The next is a present state of the Ethereum scalability ecosystem mini report, which is longer and extra in depth than a typical weblog publish.

Many enterprises have deserted personal Blockchain consortia attributable to a number of components: the absence of significant community results in personal Blockchain implementations – which are inclined to make them dearer and cumbersome to handle inside a consortium of competing entities than a shared database system – in addition to the dearth of accessibility of the DeFi ecosystem with its new and quickly rising, and, subsequently, very worthwhile asset lessons. Ethereum Layer 2 (L2) scalability options supply a chance to suit the sq. peg of Ethereum Mainnet into the spherical gap of enterprise safety, privateness, and compliance necessities since many L2 options are de facto centralized databases with intelligent cryptography. They’ll additionally present entry to the world of DeFi asset lessons, permitting Mainnet community results to spill over to enterprise options by means of these DeFi asset lessons. This makes for a brand new, and symbiotic, relationship between enterprise use instances on L2 and the Ethereum Mainnet by means of each asset and person development.


A Temporary Introduction to Layer 2 and different Scalability Options for Ethereum

The Ethereum Mainnet has turn out to be a sufferer of its personal success in that it at the moment serves as a major bottleneck for the expansion of its ecosystem; community points have arisen attributable to excessive transaction charges and the restricted variety of transactions allowed per block, endangering the financial viability of Ethereum-based protocols, start-ups, and others with sound enterprise fashions. Whereas Eth2, the subsequent model of Ethereum, guarantees a 100x improve in transaction scalability and considerably decreased transaction charges, its rollout remains to be 12 months or extra away. Ethereum scalability challenges should be addressed immediately if Ethereum desires to retain its management place as the preferred, and most used blockchain community on the earth.

Over the past 2 – 3 years a number of varieties of options have emerged that tackle the scaling and transaction price challenges. What they’ve in frequent is that every one carry out the heavy transaction processing off the Ethereum Mainnet (i.e off-chain) in varied types of centralized or decentralized computing environments, whereas Mainnet is used because the safety and knowledge integrity anchor in varied varieties. These options are what’s colloquially referred to as Layer 2 (L2) as a result of they’re options sitting above the Ethereum Mainnet, additionally also known as Layer 1.

Beneath is a short overview of the most important scalability answer classes adopted by a short description of the traits of every answer class:

  • State Channels
  • Sidechains
  • Rollups
    • Optimistic Rollups
    • Zero-Data (zk) Rollups
    • Plasma
    • Validium


Determine 1: L2 Categorizations; Supply: Token Terminal


State Channels

State channels scale the Ethereum Mainnet by performing transactions off-chain through safe channels established between events. They require a person to deposit a snapshot of the most recent Ethereum state that the person controls right into a multi-signature sensible contract; that is analogous to person deposits into fee channels on Bitcoin’s Lightning Community. This snapshot will comprise essential knowledge such because the ETH holdings of an Ethereum tackle at a given time.

State Channels enable for (practically) free off-chain transactions with instantaneous transaction finality and superior privateness as a result of solely the state channel operator and contributors within the state channel have visibility into the off-chain transactions. Consider a chess sport the place gamers place an ante to start out the sport. This transaction could be recorded on-chain and opens a channel. Particular person strikes could be signed by every participant throughout the channel. The sport would proceed till a participant leaves or the sport ends, at which level one of many gamers or the sport itself would enchantment to Mainnet for a ruling and payout of the winnings.

State channels are more likely to serve in conditions the place there are excessive site visitors peer-to-peer multi-directional transactions amongst fairly trusted events. Particular person state adjustments will happen inside these channels through signed and safe transactions, with the Mainnet or L2 consensus-based contracts serving to deal with periodic and/or “end-game” reconciliation.



Sidechains are blockchains impartial of the Ethereum Mainnet with their very own consensus fashions, e.g., Proof of Authority (PoA), Proof of Stake (PoS), and state machine mechanisms such because the Ethereum Digital Machine or different architectures. Ethereum transactions might be offloaded to such a sequence in a custodial method, lowering the burden on the Ethereum Mainnet. Relying on the community method with respect to chains (impartial multi-chain vs shared chains), transaction privateness can presumably be preserved through gated entry to a sequence.

The actual method every community takes have to be evaluated by itself to find out suitability with respect to scalability, safety, and health for objective. Some ecosystem contributors don’t contemplate sidechains to be true L2 options as they neither inherit enough safety assurances of Ethereum Mainnet attributable to a scarcity of onchain transaction knowledge nor present the flexibility to arbitrate disputes on the Ethereum Mainnet. Proponents of Eth-connected chain-based networks will argue that their Proof of Stake consensus fashions and validator fashions are as rigorous as Eth2 (which additionally makes use of a Proof of Stake mannequin) and that their operational ties with Ethereum (within the type of community contracts operating on Ethereum) present enough safety and transparency in an Eth-native kind.

We are going to define varied chain-based approaches under once we survey the scalability panorama.



Rollups are much like superior, non-custodial sidechains that obtain excessive transaction throughput whereas inheriting the safety assurances of the Ethereum Mainnet. Rollups usually fall into considered one of 4 essential classes: Optimistic rollups, zk-Rollups, Plasma, and Validium.

Rollups are options that carry out transaction execution outdoors the principle Ethereum chain, however publish transaction knowledge on Layer 1. As transaction knowledge is on Layer 1, this permits rollups to be secured by Layer 1. Inheriting most safety properties of Layer 1, whereas performing execution outdoors of Layer 1, is a defining attribute of rollups.

Three simplified properties of rollups are

  1. Transaction execution outdoors Layer 1
  2. Knowledge or proof of transactions is on Layer 1
  3. A rollup sensible contract in Layer 1 that may implement right transaction execution on layer 2 through the use of the transaction knowledge on Layer 1

Some rollups require “operators” to stake a bond within the rollup contract. This incentivizes operators to confirm and execute transactions appropriately. (Layer 2 Rollups,,

Nevertheless, “Operators” have the facility to censor transactions, if the operator-model just isn’t sufficiently decentralized as Mainnet is. The determine under organizes these classes relying on whether or not they deal with knowledge storage on-chain or off-chain, and whether or not computational correctness is enforced by means of zero-knowledge validity proofs or user-deposit-slashing fraud proofs.


Determine 2: L2 Rollup Classes; Supply:


One other differentiation between rollup options is with respect to the place computation takes place and when finality happens. For instance, the computation for ZK Validity Proofs takes place through a third-party operator (or validator, or sequencer) whose major operate is to bundle transactions and submit batches of transactions to the Mainnet. These batches comprise minimal however enough data to show the validity of the transactions. The computation of the transactions is dealt with previous to submission to L1 and finality happens as soon as validated by the L1 (or after the passage of enough L1 blocks because the rollup would possibly dictate).

Optimistic Rollups additionally compute the transactions off-chain as zk-rollups however not in zero-knowledge they usually depend on a contest process and contest interval inside which to abrogate to the Mainnet the choice as as to whether a contested transaction is legitimate or not. As with ZK Validity Proofs, operators of Optimistic Rollups are more likely to stake or be bonded such that if an operator submits a fraudulent transaction to the principle Ethereum chain, their stake is slashed.

Observe that Rollups generally don’t supply privateness to their customers. Nevertheless, new options are rising, each Optimistic (zk Optimistic) and zk Rollups (zk-zk Rollup), that do protect the privateness of their customers. These options can be mentioned within the subsequent part. Additionally, notice that zk-Optimistic Rollups have worse efficiency traits than Optimistic Rollups as a result of every transaction within the rollup block is way bigger than within the case of Optimistic Rollups, and Ethereum blocks are space-constrained by means of the block fuel restrict; a trade-off between privateness and efficiency. However, zk-zk Rollups have comparable efficiency traits as zk Rollups due to a intelligent utilization of cryptography that permits using recursive zk proofs which avoids including extra knowledge to a rollup block. Additional optimizations within the utilized cryptography keep away from a rise within the compute efficiency necessities in comparison with zk Rollups.

The above L2 options have particular efficiency, safety, financial, and value attribute that are summarized within the desk under:


Determine 3: L2 Answer Traits by L2 and Scalability Answer Class;
Matter Labs


Given the fast adjustments and optimizations of the employed applied sciences, the above evaluation of the completely different classes is merely a snapshot in time and will – and is anticipated to – change considerably over the subsequent 12 to 24 months.


Ethereum Layer 2 and Scalability Options Panorama

As already said, the Ethereum L2 ecosystem is evolving at warp pace — from the Plasma Whitepaper in 2017 to Ethereum’s largest decentralized alternate, Uniswap, going dwell on an L2 answer in 2021. Therefore, any overview of the ecosystem can be each incomplete and shortly outdated. Nevertheless, a present snapshot remains to be helpful to know the nice number of initiatives within the house, and their supposed use instances.

We are going to talk about every class and provides a number of examples in additional element and point out further, notable initiatives in the identical class with hyperlinks to their web sites or Github repositories in the event that they exist.


State Channels

Connext: Connext is a state channels undertaking that has designs on being an L2 answer not just for Ethereum but additionally a cross-chain routing hub for Ethereum’s many L2 options. The undertaking is trying to deal with a priority within the Ethereum group that Eth-based L2 initiatives won’t be sufficiently interoperable. Connext’s new cross-L2 switch system may show essential to make sure that interconnectivity between options can be available, avoiding community lock-in inside anybody scalability answer.

Different notable initiatives are the Raiden Community, Celer, and Perun.



xDai Chain: xDai Chain is an EVM-based sidechain designed to stably facilitate bigger transaction volumes; at the moment at about 70 transactions per second (TPS). The undertaking is constructed round its STAKE token, which consensus suppliers stake to economically safe the sidechain. Due to its effectivity, xDai Chain has been lately rising in reputation.

POA Community: Much like xDai Chain at ~ 70 TPS, the POA Community is an EVM-based sidechain that depends on a set of trusted consensus suppliers to course of transactions shortly and cheaply. The answer appears to be usable for nearly any use case from blockchain video games to group currencies.

Polygon PoS: Polygon is a know-how framework and protocol that permits builders to deploy and join by means of a messaging protocol various kinds of networks — EVM-based Proof-of-Stake chains, Plasma chains, and so forth. — with one another and Ethereum. Due to this fact, the intention is much like Connext, or non-Ethereum based mostly frameworks akin to Cosmos. Polygon PoS is Polygon’s sidechain answer. The Polygon token is used as a staking token on the completely different networks which might be deployed within the Polygon community of chains to economically safe the consensus suppliers. The method and structure are much like the substrate and parachain method of Polkadot.

Skale: Skale’s Elastic Blockchain Community is an Ethereum suitable POS sidechain answer that may shortly spin up application-specific sidechain cases. Validators for every sidechain are chosen as a random, periodically shuffled subset of your entire SKALE validator pool, which is incentivized by staking a token. Validators are managed and shuffled by an utility that runs on Ethereum Mainnet.

One other notable sidechain is the Loom Community.


Optimistic Rollups

Optimism: Optimism is an Optimistic Rollup implementation enabling about 100x discount in fuel utilization that’s gaining some early traction amongst some large DeFi gamers, akin to Synthetix. Optimism has constructed the OVM, an L2-based EVM such that L1 initiatives can redeploy their Solidity or Vyper sensible contracts on Optimism.

Notable initiatives migrating to Optimism: Uniswap, Compound, Synthetix

Gas: Gas was the primary Optimistic Rollup implementation on Ethereum Mainnet, going dwell on Dec. thirty first, 2020. Gas guarantees quick and environment friendly token funds, desirous to turn out to be the “Earth’s worth alternate layer.”

Arbitrum: Much like Optimism, Arbitrum, developed by Offchain Labs is an optimistic rollup community with validators economically staked in Ether, able to processing at about 100x fuel discount. The principle distinction between Optimism and Arbitrum is that Solidity and Vyper sensible contracts will have the ability to be deployed onto Arbitrum with none modifications as a result of the Arbitrum Digital Machine is similar because the EVM on the bytecode degree.

Notable initiatives migrating to Arbitrum: Reddit, Uniswap

Cartesi Descartes: Cartesi’s Descartes Rollups is a variant of optimistic rollups with interactive dispute decision, much like Truebit. As an alternative of EVM bytecode, Descartes executes the RISC-V instruction set, which permits it to run a Linux VM.

Different notable Optimistic rollup initiatives are OMGX from the OMG Community, and Dusk V3 from Ernst & Younger, a privacy-preserving Optimistic Rollup the place the rollup transactions are zk-snark proofs to protect transaction privateness, which ends up in decreased TPS as a result of dimension of the proofs.



zkSync: zkSync is a zk-Rollup answer from Matter Labs that makes use of zero-knowledge proofs from zk-snarks to appreciate each excessive throughput (~ 300 – 2,000 tps based mostly on the variety of transactions in a block) and excessive safety (inheriting Ethereum Mainnet safety assurances). Matter Labs can also be engaged on a Validium kind answer referred to as zkPorter.

Notable initiatives on zkSync: Curve, Gitcoin, Balancer, Argent

Loopring: Loopring was the primary zk-rollup deployed to Ethereum Mainnet, and has been working on Ethereum Mainnet for over one yr. Loopring’s zk-Rollup answer is at the moment centered on scaling decentralized exchanges with Automated Market Makers and Order books, and funds. The Loopring Trade and Loopring Pockets are based mostly on Loopring’s know-how. OpenOcean has now additionally migrated to Loopring.

Aztec: Aztec lately launched, which permits for absolutely personal Ether/DAI transactions. is a zk-zk Rollup which is the subsequent era of zk Rollups. The Aztec know-how permits verifying zk proofs of zk-proofs of personal transactions; in different phrases, recursive zk proofs, on the Ethereum Mainnet. Due to the recursive nature of the zk proofs, the identical variety of transactions as common zk Rollups might be positioned on the Ethereum Mainnet.

This type of zk Rollup appears to be essentially the most promising method for a lot of enterprise use instances given their sturdy privateness necessities.

Different notable zk Rollups are the Hermez Community (lately acquired by Polygon) and zkSwap.



StarkEx: StarkEx is much like zk Rollups however makes use of zk-starks as an alternative of zk-snarks, with the principle distinction being that the zk proofs are considerably bigger than the proofs for zk-snarks, and are subsequently each dearer to deposit and to confirm than for zk-snarks. The system can run both as a Validium-type system or a zk-rollup. This dynamic permits the undertaking to have increased throughput capabilities in comparison with pure zk Rollup programs. Present implementation are utilizing the Validium-type implementation.

Notable initiatives utilizing StarkEx: dYdX, DeversiFi, Paraswap, Immutable X



OMG: The OMG Plasma Community, is much like OMGX however is constructed on the Plasma structure, as an alternative of an Optimistic Rollup.

Polygon: Polygon has additionally launched a model of its Polygon sidechain mentioned above as a Plasma chain which might alternate messages with different sidechains and rollups as mentioned for the Polygon Proof-of-Stake sidechain.

One other notable Plasma chain is the Leap DAO.


What does this imply for Enterprises?

Enterprises have historically not been involved with public Blockchains as a result of safety, privateness, and compliance necessities of Enterprise Use Instances have made public Blockchains not appropriate for implementation. Nevertheless, the outcomes of personal Blockchain networks have been combined to disappointing for a number of causes. Chief amongst them, the absence of significant community results in personal Blockchain implementations, which are inclined to make them dearer and cumbersome to handle inside a consortium of competing entities than a shared database system, and the dearth of accessibility of the DeFi ecosystem with its new and quickly rising, and, subsequently, very worthwhile asset lessons from a personal Blockchain. The L2 scalability options mentioned supply a chance to not solely match the sq. peg of Ethereum Mainnet into the spherical gap of enterprise safety, privateness, and compliance necessities since many L2 options are defacto centralized databases with intelligent cryptography but additionally entry the world of DeFi asset lessons permitting Mainnet community results to spill over to enterprise options by means of these DeFi asset lessons. This makes for a brand new, and symbiotic, relationship between enterprise use instances on L2 with the Ethereum Mainnet by means of each asset and person development.


Within the subsequent installment of this weblog sequence, we’ll dive deeper into new and thrilling enterprise use instances for L2 options leveraging Ethereum Mainnet’s safety assurances and vibrant ecosystem.


Till then, keep updated on all the things EEA by following us on Twitter, LinkedIn, and Fb.

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