The role of the roll-up solution in the scalability of the second layer of the blockchain

Despite the fact that decentralized networks have made great progress; But they still suffer from the problem of scalability. At the same time as the number of users of blockchain projects increases, the density of the network and then the cost of each transaction increases. This ultimately slows down the operation and has an unpleasant effect on the user experience. Fortunately, in response to these challenges, various scalability solutions have been provided. In this article, to one of the most famous Layer 2 scalability solutionswe will talk about the Rollup solution and describe the most important rollups and their use.

What is meant by blockchain scalability problem?

In order to get acquainted with the roll-up solution, it is better to first discuss the concept of scalability. In order to be able to record more transactions in the first layer blockchains; We need to improve blockchains in terms of scalability. But why do blockchains of the first layer have problems in terms of scalability? Transactions in first-layer blockchains, such as Bitcoin and Ethereum, take place at a very low speed.

The reason for this slowness should be seen in the way transactions are processed. In these blockchains, each operation must be processed by the majority of nodes. These transactions are permanently exposed to the public and for this reason, we face challenges in terms of security and privacy. Better solutions should be provided to enable blockchain networks with better privacy and decentralization. If scalability does not improve; Still seeing an increase Gas rate (gas) And the cost of the necessary hardware to run a node will be. In addition, users who want to buy Ethereum and use their assets to make payments on decentralized platforms have to pay a higher fee rate.

The main point in designing a scalable decentralized system is that operations on different nodes are largely independent. This simple insight shows that the only way to fully scale Decentralized applicationsis to put most transactions off-chain.

What solutions are provided to improve scalability?

To solve the scalability problem, various solutions such as Payment channels, China side (sidechain), Roll-up and hybrid solutions are provided. A payment channel is a method in which a channel is created between users to increase scalability. With this, all transaction operations are done inside the channel instead of being recorded in the main blockchain, and only the final state will be recorded in the blockchain. This method has also been used in the Bitcoin network.

In the side chain, a blockchain is created separately from the main blockchain and is connected to the main network with the help of a blockchain bridge. With the help of this bridge, different currencies can be transferred between layers. The next and very important method is the roll-up solution. Rollup is a way to improve the scalability of layer two. We will get to know more about it later.

What is the rollup solution?

Rollup is a layer 2 scaling solution that operates transactions outside of the main Ethereum blockchain. However, it sends transaction-related data to the same Layer 1. Given that the transaction data is in Layer 1, networks serve users with the same security measures as Layer 1. In general, the roll-up solution has the following three features:

1. Performs all transactions outside of layer 1 (to reduce gas rate and increase transaction speed).

2. Data and proof of transactions reside in layer 1 (to maintain security).

3. With the help of the smart contract defined in layer 1, transactions are executed precisely and standardly in layer 2.

Users are usually asked to Smart contract roll-up solution to encourage them to confirm and execute transactions correctly. The Rollup solution is very useful; Because it reduces fees and, on the other hand, increases transaction and participation efficiency. It is interesting to know that to transfer assets and tokens between one solution and another, protocols such as Hop protocol is used These protocols help you transfer assets from one rollup solution to another.

How roll ups work

In this section, we are going to address the question, how does the roll-up solution work? This solution compresses transactions to reduce the cost of fees; but how? The way it works is that the rollup collects or bundles a large number of transactions outside the main chain and finally transfers them to the first layer as a single transaction. This reduces transaction costs and improves network efficiency.

How does rollup help network scalability?

Roll-up solutions, sort of Smart contracts In the Ethereum network, they act as a relay between the main chain and layer 2. Rollups actually help scale the network by moving the computational operations of transactions to a sidechain. Since the mainchain and sidechain are interoperable, they run in parallel and will be linked together. As a result, blockchain networks become more scalable; Because complex computing processes are removed from the main chain and network congestion is reduced. For example, the Ethereum blockchain can process 15 transactions in one second; However, if the roll-up solution is implemented, this amount will reach 1000 transactions per second!

The most important roll-ups and their use

In this section, we will discuss the most important roll-ups presented and then we will mention the application and important programs of each.

Optimistic roll-up solution

In this roll-up, there is no credit proof that transactions are accepted Ethereum blockchain Not sent. However, in order to ensure the security of information, a period of time is provided to users as a challenge time. During this time, users can challenge the results of transactions. By doing this, if the transactions are not verified, all of them will be removed from the list of valid transactions of the main network. If the transactions are confirmed, users can withdraw the tokens they sent during the transaction.

Among the positive features of Optimistic Rollup, we can mention the low gas cost, increased operational capacity and support for smart contract functionality. Also one of the disadvantages of this solution Long checkout time Is; Because challenge periods can last weeks. Among the most important programs based on the optimistic roll-up solution are:

• Arbitrum
• Boba
• Cartesi
• Fuel Network
• Optimism

Zero knowledge rollup solution (ZK Rollup)

Zero knowledge rollup solution (Zk-Rollups) is also known as proof of credit. With this solution, you can support a wide range of functionality for fungible tokens, non-fungible tokens (NFTs) and decentralized applications (dApps). Zero Knowledge Proof is a solution in which, instead of using the duration of the challenge, transaction confirmations are simultaneously sent to the main network, the Ethereum blockchain. This problem eliminates the time needed to check the authenticity of transactions and users can finalize and execute their transactions as soon as possible.

Among the advantages of this Zk Rollup solution, we can mention fast transfer of transactions, high security and decentralization. One of the disadvantages of the zero-knowledge roll-up solution is the possibility of users influencing the transaction order; Also, this solution does not support some Ethereum virtual machines. The most important programs based on this solution are:

• Aztec
• Immutable X
• Loopring
• Matter Labs zkSync
• Polygon Hermez

Leading challenges for roll-ups

Although the roll-up solutions have improved a lot; However, they still face shortcomings and challenges that must be resolved in the future. For example, one of these challenges is the integration of services related to decentralized financial payments or DeFi. In fact, it seems difficult to establish communication between decentralized applications in roll-up solution chains. However, there is great potential in Rollups and we will probably see more popularity of these solutions in the future.

The role of the roll-up solution in the scalability of the second layer of the blockchain was written for the first time in the Wallex blog. appeared.