Blockchain Layers Explained: Layers 0, 1, and 2

Blockchain Layers Explained: Layers 0, 1, and 2

13 min read

layers of blockchain

You might have heard about “layer one” and “layer two protocols,” but what do they really mean? That’s exactly what we’re diving into today—blockchain layer architecture. Everything you need to know will be in this blockchain layers explained guide.

At its core, blockchain is a fascinating blend of various technologies—think cryptography, game theory, and more—that come together to offer a plethora of applications, from cryptocurrencies to decentralized applications. Cryptography, the art of encoding and decoding data, plays a pivotal role here. Add to that game theory, which studies how rational beings interact strategically, and you’ve got a recipe for a blockchain network that’s both secure and transparent.

Now, here’s where it gets interesting. Because there’s no central authority overseeing things, distributed ledger technology (DLT) steps in to keep the network honest. It uses cryptography to verify transactions and data across a network of users who’ve agreed to a specific blockchain protocol. This unique blend of technologies not only fosters trust but also enables secure value and data exchange between users.

Further Reading – The Complete Blockchain for Beginners Guide: Applications and Technology


But let’s not forget about scalability. As blockchain networks grow, they need to handle more users, transactions, and data without compromising on security. That’s where the concept of layers comes into play. These layers, from the hardware infrastructure to the application layer, are designed to ensure the network remains scalable while maintaining top-tier security.


Why is Blockchain Scalability Important?

Remember when Ethereum nearly had a furball coughing fit thanks to CryptoKitties? Yep, those adorable digital cats nearly clogged up one of the most prominent blockchain networks. It was a wake-up call for many: if virtual pets can slow down a blockchain, we’ve got to talk about scalability.

So, what’s the big deal with scalability, anyway? In simple terms, scalability refers to a blockchain network’s ability to handle increasing transactions without breaking a sweat.

Scalability isn’t just a nice-to-have feature; it’s a necessity for the future of blockchain technology. As blockchain finds its way into everything from cryptocurrencies to supply chain management, its ability to scale effectively becomes crucial. A blockchain that slows down as it grows is a sign of poor scalability, and let’s be honest, nobody wants to be stuck in digital gridlock.

Now, you might have heard of the “blockchain trilemma“, which suggests that a blockchain can’t be scalable, secure, and decentralised simultaneously. It’s like a cosmic trade-off: improve scalability, and you might have to compromise on security or decentralization. But the question is, can we have our cake and eat it too? Can we scale blockchain networks without sacrificing these core principles?

To put things into perspective, let’s talk numbers. Traditional platforms like Visa’s VisaNet can process a staggering 24,000 transactions per second. In contrast, Bitcoin’s main chain can only handle about seven. That’s why blockchain developers are constantly tinkering with layers and smart contracts to boost transaction throughput. The aim? To make blockchain not just a competitor but a frontrunner in the digital landscape.

Layer two technologies and smart contracts are among the innovations being explored to automate transactions and improve scalability. By optimizing these layers, the goal is to elevate blockchain’s transaction processing speed and make it a force to be reckoned with in the commercial world.


Structured Layers of the Blockchain Architecture

layers of blockchain architecture


You probably know how a sandwich is made. You’ve got your bread, your meat, your veggies, and maybe a slice of cheese or two. Each layer serves a purpose, and together, they make a delicious meal. In tech, it’s commonplace for systems to use the concept of layers or stacks, and Blockchain is no different. Technically speaking, you can break down a blockchain into five main layers:


1. The Hardware Layer

The hardware layer serves as the foundational infrastructure of a blockchain network. It consists of nodes, which are individual computers or clusters of computers that contribute computational power to the network. These nodes are essential for transaction validation and data storage.

Blockchain content is securely stored in data centres, accessible through a client-server architecture. In this setup, client devices request specific data from application servers, facilitating the interaction between users and the blockchain network.

In addition to the client-server model, blockchain employs a peer-to-peer (P2P) network architecture. In this network, nodes, or computers, share data and resources directly with each other, bypassing the need for a centralized server. This P2P network is responsible for computing, validating, and recording transactions in a shared ledger, resulting in a distributed database that contains all pertinent data and transaction records.


2. The Data Layer

Each transaction is encapsulated within a block, the fundamental unit of a blockchain. These blocks contain essential information such as the amount of cryptocurrency transferred, the receiver’s public key, and the sender’s private key.

A blockchain can be visualized as a linked list of these blocks in terms of its data structure. Each block is connected to its predecessor and successor, except for the genesis block, which is the first block and only points forward. Pointers are used to establish these connections, serving as variables that indicate the position of another block within the chain.

A key feature within each block is the root hash of a Merkle tree, a binary tree of hashes that provides an additional layer of security and data integrity. The Merkle tree works in conjunction with cryptographic techniques and consensus algorithms to fortify the blockchain system.

To further enhance security, each transaction is digitally signed using a private key. This signature can be verified by anyone with access to the corresponding public key, ensuring the transaction’s authenticity. Digital signatures play a pivotal role in maintaining data integrity; any alteration to the data would invalidate the signature.

Further Reading – Storing Crypto: Crypto Exchange vs Wallet

The data within the blockchain is encrypted, rendering it unreadable without the appropriate decryption keys. This encryption, along with digital signatures, safeguards the identity of the sender or owner, making the data tamper-proof and ensuring its confidentiality.


3. The Network Layer

After the data layer, we come to the network layer, a vital cog in the blockchain machinery that manages the intricate web of communication between nodes. Often referred to as the P2P (Peer-to-Peer) layer, this layer serves as the backbone for inter-node interactions, including the discovery of nodes, transaction propagation, and data distribution.

The network layer ensures that transactions and blocks are efficiently disseminated across the network. It plays a pivotal role in keeping the blockchain network synchronized and in a state of consensus.

One of the key responsibilities of the network layer is to keep all nodes updated about the transactions being validated across the network. This ensures that every node has the most current and accurate version of the blockchain, thereby maintaining the network’s integrity.

Finally, it’s worth noting that the actual transactions on the blockchain are executed by these nodes. They validate, record, and propagate transactions, making them the workhorses that keep the blockchain running smoothly.


4. The Consensus Layer

This layer is where the magic happens, ensuring that all nodes on the network are on the same page regarding the validity of each transaction.

Whether it’s Proof of Work (PoW) in the case of Bitcoin or Proof of Stake (PoS) as seen in Ethereum 2.0, the consensus mechanism is the rulebook that nodes follow to agree on the state of the blockchain. These mechanisms serve as the referee in the decentralized arena, determining which transactions get added to the blockchain.

If we were to single out the most crucial layer in a blockchain, it would undoubtedly be the consensus layer. It’s the layer that gives blockchains like Ethereum their unique ability to operate without a central authority.

This layer takes on the heavy lifting of not just validating transactions but also sequencing them in the correct order. It’s like an orchestra conductor, ensuring each section comes in at the right time to create a harmonious melody – that is, a secure and reliable blockchain.

The goal of the consensus layer is to achieve network-wide agreement. It ensures that every participant agrees on the validity and order of transactions regardless of their role or location. This is what makes the blockchain a source of truth that can be trusted by all.

Further Reading – Understanding Types of Blockchain Consensus Mechanisms 101 Guide


5. The Application Layer

This is where the blockchain comes to life for the average user. It’s the playground where all sorts of applications are built, from your everyday wallets and DeFi platforms to the trending NFT marketplaces.

While the user interface might look similar to what you’re used to, the real difference lies in the backend. Unlike traditional apps, these applications store their data in a decentralized manner, thanks to the blockchain network they’re built upon.

The Application Layer is a hub of smart contracts, chaincode, and decentralized applications (DApps). They’re divided into two sub-layers: the application and the execution layers.

The former is what you interact with, and it includes scripts, APIs, and user interfaces. The latter is where transactions are executed according to the rules set by smart contracts and chain codes.

When you initiate a transaction, it starts at the Application Layer and moves down to the Execution Layer. Here, it’s validated and executed based on pre-defined rules, ensuring the deterministic nature of the blockchain. In simpler terms, it makes sure that ‘A’ always leads to ‘B,’ providing a reliable and predictable experience.


Blockchain Layers Explained: Understanding Blockchain L0, L1, and L2 and L3


Another approach to understanding the layers of blockchain technology is by diving into its multi-layered protocols. The blockchain network is structured into four distinct layers: Layer 0, Layer 1, Layer 2, and Layer 3.


Layer 0

Think of Layer 0 as the bedrock of the blockchain universe. It’s not just a single entity but a complex web of hardware, protocols, and connections that lay the groundwork for the entire blockchain ecosystem. You could even call it a “network of blockchains.”

One of its standout features is inter-chain operability, which essentially allows different blockchains to “talk” to each other. This is crucial for tackling scalability issues that might arise as the technology evolves. To incentivize participation and further development, Layer 0 often utilizes a native token.

Notable examples of Layer 0 include Polkadot, Avalanche, and Cosmos. It’s the foundational stage that enables the functioning of various blockchain networks


Layer 1

Layer 1 handles the core functions that keep the system running smoothly. This includes everything from dispute resolution and consensus mechanisms to programming languages, protocols, and restrictions.

However, this layer isn’t without its challenges. Scalability is a big one.

Taking L1 blockchains that use the Proof of work mechanism as an example, the computational power needed to solve and add blocks to the chain increases as more people join the blockchain network. This can lead to higher transaction fees and longer processing times, which isn’t ideal for users.

While advancements like proof-of-stake and sharding have been introduced to alleviate these issues, they haven’t been a silver bullet. These methods do help by dividing computing tasks into smaller, more manageable pieces, but they’re not a complete solution to the scalability problem.

Prominent examples of a Layer One blockchain include Ethereum, Cardano, Bitcoin, and Solana. Each has its own unique approach to solving the scalability issue, but it remains a work in progress.


Layer 2

Layer 2, often referred to as L2 solutions, enhances the base layer, or Layer 1, of the blockchain. Its primary role is to boost scalability by offloading some of the transactional load from the main blockchain. This allows the core blockchain to focus on essential tasks like deposits and withdrawals, while Layer 2 handles the nitty-gritty details of individual transactions.

In simpler terms, think of Layer 2 as a set of mini-networks that operate on top of the main blockchain. These mini-networks process transactions independently, then report back to the main chain. This division of labour significantly speeds up transaction times and reduces costs.

One well-known example of a Layer 2 solution is Bitcoin’s Lightning Network, which enables faster and more cost-effective transactions by operating off-chain.

So, how does Layer 2 differ from Layer 1? While Layer 1 is the foundational blockchain layer that handles the core operations, Layer 2 acts as a third-party integration that enhances the system’s overall throughput.


Layer 2 Scaling Solutions

The rise of Layer 2 protocols has been an important in addressing scalability issues, especially in Proof of Work (PoW) networks. Let’s explore the various types of Layer 2 scaling solutions that are making waves in the blockchain ecosystem.


Nested Blockchain

Think of a nested blockchain as a hierarchical structure within the main blockchain. It involves two blockchains layered and running on one another. In this setup, Layer 1 sets the ground rules, while Layer 2 executes the operations. It’s similar to a corporate hierarchy where tasks are delegated to various departments, which then report back to the top management. This enhances scalability.


State Channels

State channels are designed to boost transaction speed and capacity by establishing a two-way communication link between the blockchain and off-chain transaction channels. Transactions are conducted off-chain and then finalized on-chain, reducing the immediate need for miner validation. Examples include Bitcoin’s Lightning Network and Ethereum’s Raiden Network. While state channels offer increased scalability, they do compromise a bit on decentralization.



Sidechains operate parallel to the main blockchain and are tailored for handling bulk transactions. Unlike state channels, transactions on sidechains are publicly recorded. Each sidechain has its own consensus mechanism and often uses a utility token for data transfer between the main and side chains. The primary role of the main chain here is to offer security and resolve disputes.



Rollups are another Layer 2 solution that process transactions off the main network and then upload the transaction data back to it. They offer the advantage of increased transaction throughput and lower gas costs. Since the data resides on the base layer, Layer 1 can ensure the security of rollups.


Layer 3

Layer 3, often dubbed as the application layer, serves as the user-friendly interface that masks the complex technicalities of the underlying layers. It’s the layer that brings blockchain technology into our daily lives, making it more than just a buzzword but a tool with real-world applications.


Wrapping Up

Scalability remains a significant hurdle for mainstream adoption of blockchain technology. As cryptocurrency demand surges, the need to enhance blockchain protocols becomes increasingly urgent. Layer 1 serves as the bedrock of decentralized systems but faces its own scalability challenges. Layer 2 solutions aim to alleviate these issues, yet most current Layer 3 applications (DApps) still operate primarily on Layer 1, leading to suboptimal performance.

While Layer 3 apps bring real-world utility to blockchain, they can’t fully realize their potential without a strong, scalable foundation. The future likely lies in a harmonized system that effectively tackles the scalability trilemma, allowing each layer to perform optimally and contribute to the blockchain’s overall value and utility.

For blockchain to go mainstream, it’s crucial to address scalability across all layers, ensuring that they work in tandem to offer both robustness and real-world applicability.

Now that you are familiar with our blockchain layers explained guide, let’s dive even further with our FAQ.


Frequently Asked Questions on Blockchain Layers

What are layers in blockchain?

Blockchain layers encompass Application, Services, Protocol, Network, Data, and Infrastructure. These form the complete architecture of a blockchain. Additionally, terms like L1 and L2 often refer to scalability solutions within the blockchain.


What is Layer 1, Layer 2, and Layer 3 in blockchain?

Layer 1 is the foundational blockchain layer responsible for dispute resolution, consensus mechanisms, and core programming (e.g., Bitcoin, Ethereum). Layer 2 enhances scalability and allows for third-party integrations. Layer 3 is where decentralized applications (dApps) and user interfaces reside.


What layer is Bitcoin?

Bitcoin operates primarily on Layer 1 as it forms the foundational blockchain for its network.


What layer is Ethereum?

Ethereum operates on Layer 1 but also supports Layer 2 solutions for better scalability and has a rich ecosystem of Layer 3 dApps.


Is Doge a Layer 1?

Yes, Dogecoin (Doge) operates on Layer 1 as it has its own blockchain and consensus mechanism.


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