Original title ：《Arbitrum yes Rollup The optimal solution of the scheme ？》

5 month 28 Japan ,Arbitrum Announcing the opening of the main network to developers . The next day ,Uniswap Community access 100% I've got the approval rating of 「 stay Arbitrum Upper Department Uniswap v3」 Proposal for . These new developments will once again bring this Ethereum Layer2 The solution of layer expansion has become a hot topic . 

Ethereum network congestion and GAS The problem of excessive fees has a long history , The community has also put forward various expansion plans , only Layer2 There are many ways to expand the layer , Including status channels 、 Side chains and Plasma、Rollup And so on. , among ,Rollup Highly respected . 

Rollup The biggest feature of the expansion plan is , The actual calculation and storage of smart contracts are done under the chain , Transaction data is stored on the Ethereum main network through a series of compression techniques , Security is guaranteed by the Ethereum blockchain . Founder of Ethereum Vitalik Buterin Many times in public that ,Rollup It is the best choice for Ethereum to expand its capacity in the short and medium term . 

because Rollup Class project Optimism The online time of the main network is determined by 3 The month is extended to 7 month , This gives the same kind of project Arbitrum A starting point . Just opened the main network Arbitrum Now it has priority over Optimism Put into use . 

In addition to developers can enter the main network deployment contract , Users can also use wallets MetaMask Replace RPC node , Get into Arbitrum Test network and application , The team provided Arbitrum Asset Bridge Bridge arbitrum, Ethereum can be Layer1 layer Kovan Test network assets and Arbitrum The test network is directly interconnected , Currently supported ETH And ERC-20 and ERC-721 Multiple assets under two standards . 

Arbitrum Rollup What is it? ？ What is the operation mechanism ？ What applications are deployed ？ And Optimistic Rollup and ZK Rollup What's the difference? ？ In this issue DeFi Honeycomb will bring relevant interpretation .

• brief introduction

 

Arbitrum yes OffchainLabs Ethereum developed by the team Layer2 Layer expansion plan , Can achieve high throughput , Let developers deploy at low cost 、 Operating smart contracts , At the same time, it can keep the security without trust . 

Arbitrum It was a research project at Princeton University , since 2018 Ethereum expansion technology Rollup Since the concept was mentioned , The team is committed to using Rollup Technology expansion solves Ethereum congestion .  simply ,Arbitrum It's an off chain protocol managed by Ethereum's on chain contract , Use of the Rollup technology . Let's put it in the vernacular ,Rollup It's the methodology of Ethereum expansion technology ,Arbitrum Turn technology theory into reality . 

Rollup Technology strives to record all transaction data on the main chain , The core idea is to distribute a large amount of transaction data in the block , Aggregate into a deal , Publish to the main chain ; The actual calculation and storage of the contract are completed under the chain . In this way, the computing and storage pressure of the main chain will be reduced , So as to achieve high throughput of the network . 

This year, 1 month ,OffchainLabs stay Arbitrum The test network is up DeFi Ecosystem Demo product , The first applications to be supported include the decentralized transaction protocol Bancor, Decentralized Auction tools Bounce.finance, Decentralized perpetual contract exchanges MCDEX And so on . 

5 month 28 Japan Offchain Labs Team announced that Arbitrum Test version of Ethereum main network has been deployed Arbitrum One, Open to developers , There are more than 250 A team applied for access to the developer test network .（ In order not to confuse Arbitrum Technology and Ethereum Layer2 chain , The team named the main network chain Arbitrum One, namely Arbitrum One It's using Arbitrum Technology to build the main Ethernet Layer2 chain ）. 

• Operation mechanism

 

Rollup The main feature of is that all transaction data are recorded on the chain , in other words ,Arbitrum Put the safety part on the Ethereum chain , The actual calculation and storage are executed under the chain . 

such as ,A The user is in Arbitrum Generate a transaction data on , This data will be recorded on the Ethereum chain , It's for everyone to check the deal . But the computing and storage involved in this deal are in Arbitrum On the chain , It is carried out under the Ethereum chain . It's expanded in this way , Lighten the Ethereum chain . 

The user is in Arbitrum All transactions executed on the chain , All need to be submitted to... Running on Ethereum Inbox（ inbox ） Intelligent contract , Arbitrum Periodically through the aggregator , Package multiple transactions , Nodes submitted to Ethereum in batch . such as , Every time 5 Minutes or 10 The clock , Send to Ethereum containing Arbitrum Hash of the complete status of all transactions that take place on , This hash will be recorded on the Ethereum chain , Open to all . 

Because of all Arbitrum All transaction data will be released to Ethereum , So the cost of each transaction and Arbitrum The number of transactions that can be supported per second , Will be limited by the amount of data allowed to be published to Ethereum during this period of time . 

therefore ,Arbitrum Will optimize and compress the transaction , For example, after aggregating multiple transactions through aggregator , Submit in bulk , This will minimize the number of times you need to publish content on the chain , Increase throughput ; The cost of each transaction is also shared equally , Achieve the effect of reducing transaction costs . 

• characteristic

 

No trust security  

Because transaction data is recorded on Ethereum , in other words Arbitrum Security is rooted in Ethereum , Security is guaranteed by the Ethereum blockchain . 

And Ethereum EVM Fully compatible with  

Ethereum and other compatible EVM The application on the chain doesn't need any modification , You can migrate directly , Support Solidity And more EVM Language , Developers can easily migrate existing contracts or develop new ones . 

License free contract deployment  

No matter who you are , You can be there immediately Arbitrum The contract is signed , And it's very easy , It's like changing your RPC That's easy , The principle is Arbitrum Direct operation EVM Code , No need for any custom tools or translators . 

Extensibility  

Move the calculation and storage of the contract out of the Ethereum main chain , To achieve higher throughput . 

Minimum cost  

Batch submit transactions through aggregator , To minimize Layer1 The processing cost of the layer , Minimize the cost sharing of each transaction . 

• application

 

Uniswap（UNI）

The community is about UniswapV3 Deploy to Arbitrum The proposal is in 5 month 29 The voting ended on May , Finally, there was overwhelming support ,Uniswap founder Hayden Adams A tweet means , If passed by vote , Will V3 Smart contracts deployed to Arbitrum, The deployment plan has now begun . 

SushiSwap（SUSHI） 

5 month 30 Japanese official Xuan ,SushiSwap Already in Arbitrum Upper Department . 

Decentralized trading platform DODO（DODO） 

6 month 1 Japanese official Xuan ,DODO Of V1 and V2 Smart contracts have been deployed to Arbitrum Main network . 

Decentralized exchange Bancor（BNT） 

1 The end of the month has been in Arbitrum Development and deployment on the Internet , Users can enter the application through the test network as early as possible . 

Decentralized derivatives trading platform MonteCarloDEX

MCDEX Original name MonteCarloDEX, The first to adopt Arbitrum The expansion project ,MCDEX I've been Arbitrum Test running online ,MCDEX V3 Will be in 5 month 28 Deploy to the main network every day . 

Arbiswap 

Offchain Labs Team in 2020 year 11 Month uses Uniswap Open source code is created in Arbitrum Decentralized exchanges on the Internet , Interface and Uniswap similar , The only difference is Arbiswap There is an asset bridge on the page Arbitrum Bridge , Users use it to implement L1 and L2 The asset transfer of the layer . Users can use MestMask Change your wallet Arbitrum Test network RPC Node to experience Arbitrum Transaction speed and low cost on the Internet . 

Team tests show that , The etheric fang Layer 1 It can only process at most per second 7 pen Uniswap transaction , and Arbiswap Even in Arbitrum When the chain is fully loaded , Up to... Per second 390 pen , At the same time Gas Cost reduction 55 times . 

Another thing to note Arbitrum There is no official issue of any related token , stay Arbitrum In the main network test version ETH As fuel , All costs use ETH payment .  

• Rollup The difference between different schemes

 

It is said that , No contrast, no harm . In the morning Arbitrum We already have the first mover advantage , It's also technically better than other Rollup Class expansion technology shows the characteristics of differentiation in practice . 

Rollup Technology is currently practiced by multiple teams , To form the Arbitrum Rollup、Optimistic Rollup as well as ZK Rollup programme , Like all kinds of schools , They all have their own supporters . 

Arbitrum Rollup、Optimistic Rollup It's similar in the framework process , And ZK Rollup The difference lies in the verification of the final transaction results . The first two use fraud proof , and ZK Rollup Zero knowledge proof is adopted . 

The so-called fraud proof , It's assuming that all the submitted traders are good people , Unless proven guilty . Some people question , The party who raises a question should first pledge a certain amount of deposit , In case of malicious attack ; If the chain proves right , Then the deposit pledged by the doubting party will be confiscated . 

such as , node A Submitted a transaction data generated on the chain , and B Disagree , So how does this deal go ? How the Internet continues to work ？ There are basically two options ： To prove fraud or to re execute a transaction .Arbitrum Rollup and Optimistic Rollup They all use fraud proof .

ZK Rollup programme  

The user can actively prove the result of the transaction , Transfer and withdrawal can be quickly confirmed . 

such as , user A stay ZK Rollup Class on the chain transactions , The aggregator submits the transaction data to Ethereum ,ZK Rollup You can immediately verify if there is a problem with the aggregator providing transaction data . This way, in terms of security and the finality of the transaction , They all have advantages . 

however ,ZK Rollup In the process of proving , Computing costs are high , It can only be used to realize simple transaction and transfer , In deploying and operating complex smart contracts , It's going to cost too much . Besides , because ZK Rollup The development language level is too high , Are not compatible EVM, Application migration on Ethereum is also difficult . Although the founder of Ethereum Vitalik Recognized in public ZK Rollup programme , But these problems can not be solved in a short period of time . 

Arbitrum Rollup and Optimistic Rollup 

The fraud proofs adopted by both of them are time-delay , The default is that the submitted data on the chain is correct ,Layer1 Check again to see if it's right . 

Arbitrum Rollup and Optimistic Rollup The biggest difference between the two is when there are differences in the process of fraud proof , There are different ways to resolve differences . in other words , When a transaction is executed, after execution , If the status is controversial , How to solve ？ 

Arbitrum Multiple rounds of fraud proof were used ,Optimistic Using a single round of fraud proof . 

Arbitrum It's multiple rounds of fraud proof , In other words, the controversial points are disassembled layer by layer , Find the most critical issue , Then use the Ethereum contract to determine if it's right . and Optimistic Single round fraud proof , You need to take the whole Layer 2 The deal moved to Layer1 On the main chain , Verify... On the main chain , This will increase the processing cost of calling contracts on the main chain . 

In addition to the round of fraud proof , Is it fully compatible with Ethereum EVM It's also Rollup The focus of the solution , After all , Yes Layer2 The demand for the Internet is increasing , Mainly because DeFi After the outbreak , The congestion and high cost of Ethereum are highlighted . 

Arbitrum Rollup Fully compatible with EVM; By contrast ,Optimistic Rollup Also compatible EVM, But not yet 100%. Decentralized financial agreements dForce Founder Yang mindao is very concerned about this ,（ use Optimistic Rollup technology ）Optimism no 100% compatible EVM It's a major strategic misjudgment , Not to mention the delayed launch of the market ,「 These people don't understand ,99.9% Compatible and 100% Incompatibility is one thing .」