![]()
Scalability has always been a key focus of the industry, and it just so happens that blockchains are currently facing the problem of “scalability triple dilemma”, and the modular blockchain that started with Celestia is proposing solutions around its scalability, high level of security, and decentralization, and modular blockchain is becoming a mainstream narrative, crypto KOL Thor Hartvigsen wrote an article on “Modular Blockchain and Its Intrinsic Value”, compiled by BlockBeats as follows:
PART 1: Start with the basic concepts
Issues that need to be improved today:
-
Trustless cross-chain communication
-
Rollup scalability when the number of transactions grows large enough
-
Maintain a high level of security and decentralization while aiming to increase throughput (blockchain triple dilemma)
![]()
First, to ensure a thorough understanding of these concepts, we need to establish some terminology, as shown below:
![]()
blocks
A block is an integral part of a blockchain, and a single block consists of two components: the block headre block body, the header contains the hash of the previous block, timestamp and other data, and the body contains all the transactions in the block.
![]()
One of the most popular scaling strategies in the market is to have larger blocks (Solana).
Larger blocks = increased throughput, but there are some issues at the decentralization level.
Larger blocks = larger data required by nodes, and few people can afford more expensive hardware that can carry huge amounts of data.
node
A full node needs to store the entire blockchain and all transactions that have been made since the first block, and in order to transact on the blockchain, it needs to ensure consensus, ensure that data is available, and that blocks are valid.
Light Node (Light Client)
Light nodes are used for rollups and outsource most of the work to full nodes, they don’t validate transactions, but check if each block has consensus and whether the block data is available to the network, most light nodes rely on the “majority honest assumption” that the majority of participants (like validators) are honest, light nodes require less hardware, more nodes, but overall weaker security (sometimes).
![]()
Rollup (on Ethereum)
Rollup/L 2 is a chain built on top of Ethereum, using the Ethereum mainnet as the settlement layer, and the Rollup can be thought of as a separate execution layer and returns the transaction package to the mainnet for validation.
There are currently two types of rollups: Optimistic Rollup and ZK Rollup.
Blockchain Layer:
Blockchain can be divided into 4 layers:
-
Execution layer, which provides the environment for Dapps and processes transactions in them;
-
Data availability layer: Nodes receive blocks from the block generator and check if the data (transactions) are publicly available
-
Consensus layer: determines the order of transactions
-
Settlement Layer: Determines the actual state of the blockchain (final)
Monolithic vs. modular
Monolithic blockchains are chains that are made up of all of the above 4 layers, so monolithic needs to handle all of the above, which is the case with Ethereum and most other blockchains you know.
A modular blockchain is a chain that outsources one or more of these 4 layers to an external chain, which can reach new levels of scalability due to the fact that modular blockchains can focus on specific elements.
![]()
Some of the basic concepts are explained above and summarized in tabulated as follows:
![]()
Rollups (e.g., Arbitrum, Optimism) on Ethereum currently act as the execution layer and implement the data availability layer, consensus layer, and settlement layer through Ethereum mainnet, which will use “on-chain data availability” to publish data to a specified L 1 (Ethereum).
Conversely: a rollup with “off-chain data availability” publishes its data to a location other than the specified L1, and the rollup can still use Ethereum as the settlement layer, but Celestia will act as the data availability layer by publishing data in this way (off-chain data availability).
![]()
Here are the different types of rollup structures on Ethereum:
-Monolith = Ethereum mainnet
-Rollup=e.g. Arbitrum, Optimism (acts as an execution layer and uses Ethereum for others)
-validium=“Rollup of off-chain data availability”, e.g. Celestia
![]()
PART 2: Learn more about Celestia
Celestia is a modular blockchain network, and the blockchain and all VM rollups (not just EVMs) can use Celestia as a data availability layer and consensus layer, as shown in the figure below, Celestia provides different solutions for modular scaling, such as “Sovereign rollups, Celestium, etc.”
![]()
First of all, you need to understand the “data availability layer”
Data availability: As a node, it is possible to receive a block from the block generator and needs to verify that the data is public (published) in order to add it as the next link in the blockchain.
Data availability issues: Occur when data is retained.
Specifically, the block generator does not reveal the data of a new block (in the case of a data hiding attack), and the node is suddenly unable to approve the block because it cannot read the data, which is a common problem in rollups.
Introduction to Data Availability Sampling (DAS):
The light client (which I covered earlier) can verify data availability without having to download all the data, and the light client runs a small sample of the data and gets 50% certainty that the data is actually published every time.
![]()
In many cases, light nodes only need to download less than 1% of the data to ensure that 99% of the data is published, which is a big improvement!
Learn more
Going back to light clients, as I said earlier, light nodes are much less expensive in terms of hardware requirements, but because they rely on “majority honest assumptions”, they are less secure.
What about the light client of the “few honest assumptions”?
![]()
For example, Celestia’s light nodes use data availability sampling by downloading a small portion of the data, and they rely on the “few honesty assumptions” (assuming that a small number of blockchain traders are honest and follow the rules of the protocol), which greatly improves security.
![]()
The following figure shows the comparison of different nodes and clients
![]()
Now let’s take a look at Celestia’s different solutions:
-Sovereign Rollup
-Sovereign Rollup itself handles the execution layer and settlement layer, rather than using Ethereum as the settlement layer like Arbitrum and Optimism.
![]()
Benefits of Sovereign Rollup:
-
Greater freedom over the execution environment
-
No shared computing resources
-
A hard fork is possible after something goes wrong
Sovereign Rollups are more similar to L 1 and can be bridged to other Sovereign Rollups and settlement layers.
Cluster
A blockchain cluster is a set of blockchains and rollups that can communicate with each other in a “trust-minimized manner”, a trust-minimized bridge between two chains that does not require a middleman or majority honest assumption to ensure the safety of funds.
![]()
An example of a cluster is Ethereum and its Rollup (L2) or different chains in the Cosmos ecosystem that are capable of intra-cluster communication (trust-minimized bridges rather than trusted bridges).
Here’s everything combined with Celestia:
Trust-minimized communication (intra-cluster communication) requires a “few honest assumptions”, which is exactly what Celestia takes advantage of, and light nodes can use data availability sampling. Trust-minimized bridges are much more secure, forming a “cluster” of the chain and “intra-cluster communication”, so Celestia provides the key parts of the rollup to form a cluster and communicate in a trustless manner.
Celestia Quantum Gravity Bridge and Celestium
The Celestia Quantum Gravity Bridge is a data availability bridge between Ethereum and Celestia that allows for L2 “off-chain data availability” (Ethereum rollups using Celestia as the data availability layer) on Ethereum.
![]()
Celestium is an L2 rollup built on top of Ethereum, using Celestia instead of Ethereum as a data availability layer, and still using the Ethereum mainnet for settlement and consensus, with other L2s following suit to improve its scalability.
![]()
Summary:
Celestia is a standalone data availability layer, and in some cases a consensus layer, and Rollups can use Celestia to improve scalability due to the inherent techniques of data availability sampling and “honest” light nodes.
PART 3: Stop at Fuel Labs
Let’s end this topic by talking about Fuel Labs, which is building an execution layer that can be implemented with Ethereum and Celestia, maintaining a high level of security and decentralization premise to scale throughput.
![]()
Learn more about Fuel Labs:
-
One of Fuel Labs’ products is their Optimistic Rollup, which they built to scale Ethereum. Include:
-
Trust-minimized bridge between Fuel and Ethereum
-
FuelVM - Parallel verification by running smart contracts using “UTXO” (unconsumed transaction outputs).
Sway programming language
![]()
In a nutshell, FuelVMs can run multiple processes at the same time (parallel validation) because Celestia works with all VMs, and Fuel can also use Celestia as a data availability layer and/or consensus layer to start rollups.
![]()
