Ethereum Dencun Upgrade Year One: Deep Dive Into Layer2 Ecosystem Transformation

In March 2024, Ethereum underwent its most significant upgrade since "The Merge" — the Dencun upgrade (codenamed "Deneb + Cancun"). The centerpiece of this upgrade was EIP-4844 (Proto-Danksharding), which introduced a "data blob" mechanism for Layer2 networks, fundamentally transforming L2 transaction cost structures. Now, nearly a year since the Dencun upgrade, how has this technical revolution reshaped the Layer2 ecosystem? This article provides an in-depth review of the Rollup sector's evolution over the past year.

The Technical Essence of the Dencun Upgrade

To understand the Dencun upgrade's impact on Layer2, it's essential to grasp the design logic of its core technology — EIP-4844. Prior to EIP-4844, when Layer2 Rollups submitted data to the Ethereum mainnet, they needed to write all transaction data to Ethereum's Calldata storage space, which came with extremely high storage costs and served as the primary source of Gas fees for Layer2 users.

EIP-4844 introduced a data structure called Blob (Binary Large Object). Blobs are temporary data carriers specifically designed for storing Rollup transaction data, with significantly lower storage costs compared to traditional Calldata. Even more importantly, Blob data automatically "expires" from the Ethereum network after approximately 18 days, eliminating the need for permanent storage and further reducing Data Availability costs.

According to the Ethereum Foundation, this design reduced Layer2 data processing fees by approximately 10x or more. Lower fees mean more users can afford on-chain interactions, laying the technical foundation for user growth in the Layer2 ecosystem.

TVL Migration: The Funding Flow Indicator

One of the core metrics for measuring Layer2 ecosystem development is TVL (Total Value Locked). Following the Dencun upgrade, Layer2 TVL experienced significant changes.

Before the upgrade, Ethereum mainnet's TVL consistently dominated, with Layer2's TVL share being relatively limited. After the upgrade, as transaction costs dropped, substantial DeFi activity began migrating to Layer2. User activity on mainstream Optimistic Rollup networks like Arbitrum and Optimism increased notably, with the rise of Base chain becoming a hallmark event of this cycle.

From the market competitive landscape, the Dencun upgrade further strengthened the Optimistic Rollup camp's first-mover advantage. Arbitrum, leveraging its ecosystem prosperity and relatively lower fees, maintained its leading position in TVL rankings; Optimism, through OP Stack's modular architecture, also attracted multiple partner networks to adopt its tech stack.

Meanwhile, the zk Rollup camp (zero-knowledge proof Rollup), despite high expectations for technical security, experienced relatively modest TVL growth during the Dencun cycle. Projects like zkSync Era and Starknet continued advancing technical development, but still face challenges in user experience and ecosystem richness.

Fee Changes: The Most Direct User Perception Improvement

The most immediate impact of the Dencun upgrade on regular users is reflected in Gas fees. Previously, executing a Uniswap transaction on Ethereum mainnet could cost dozens or even hundreds of dollars in Gas fees; on Layer2 networks, the same operation typically costs only a few cents. The sharp fee reduction made micro-transactions economically viable, driving the普及 of DeFi strategies.

According to market observations, in the months following the Dencun upgrade, Layer2 networks' average daily transaction volume showed a clear upward trend, with some mainstream L2s achieving severalfold growth in daily active addresses. This data indicates that the fee reduction strategy effectively activated on-chain economic activity.

Rollup Technology Evolution: From Scaling to Modularization

The Dencun upgrade not only reduced Layer2 operational costs but also catalyzed accelerated evolution in Rollup technology.

First, the rise of Rollup-as-a-Service (RaaS) models. The maturation of technology frameworks like OP Stack and Arbitrum Nitro has enabled developers to deploy their own Rollup networks more easily. This "modular Rollup" approach has lowered the technical threshold for launching a Rollup, promoting diversified development of Layer2 networks.

Second, intensified competition in the Data Availability Layer (DAL). Celestia, a modular blockchain focused on data availability, gained significant attention after the Dencun upgrade. More Layer2 projects began considering outsourcing data availability to specialized layers to further reduce costs.

Third, improved technical maturity of zk Rollup. The launch of zkEVM-compatible projects like Polygon zkEVM and Scroll marked zk Rollup's transition from theory to practice. Although zk Rollup's overall market share still trails Optimistic Rollup, the debate over technical approaches continues.

Competitive Landscape: Multi-Chain Contestation and Differentiated Positioning

One year after the Dencun upgrade, the Layer2 sector exhibits clear differentiated competition dynamics.

Arbitrum: Consolidating Ecosystem Dominance

Through the dual-chain布局 of Arbitrum One and Arbitrum Nova, Arbitrum has continued consolidating its leading position in TVL and ecosystem project counts. Its ecosystem encompasses mainstream DeFi protocols like Aave, Uniswap, and GMX, forming a relatively complete on-chain financial infrastructure.

Optimism: Modular Ecosystem Expansion

With OP Stack as its core, Optimism has built a vision of multi-chain interconnectivity. Base chain's rapid rise represents the biggest highlight of the Optimism camp during this cycle. Launched with support from Coinbase and positioned for social and consumer-grade application scenarios, Base achieved significant TVL growth leveraging Coinbase's brand backing and user base.

zk-Rollup Newcomers: Long-Term Technology-First Positioning

Technology-focused projects like zkSync Era, Starknet, and Polygon zkEVM, while not yet achieving breakthrough in user scale, hold theoretical advantages in security and finality. With continued iteration of zk technology, this camp is expected to capture greater market share in the future.

New Entrants: Specialized Scenario Focus

After the Dencun upgrade, some Layer2 networks focused on specific scenarios began emerging. For example, IMX (Immutable X) specializing in gaming and NFTs, Linea focusing on zk programming — these projects seek differentiated positioning through deep optimization of vertical scenarios.

Challenges and Outlook: Layer2's Next Chapter

Despite the Dencun upgrade bringing significant short-term benefits to Layer2, the sector still faces multiple challenges.

First, the sequencer decentralization issue urgently needs resolution. Currently, most mainstream Layer2 networks employ centralized sequencers, where user transactions must be sorted through centralized servers before being submitted to the mainnet — creating tension with Ethereum's decentralization ethos. OP Stack and Arbitrum are advancing research on decentralized sequencers, but full implementation remains pending.

Second, the cross-chain liquidity fragmentation problem persists. Asset migration between Layer2 networks still requires bridging, which not only introduces time delays but also carries security risks. The demand for cross-chain liquidity aggregation and unified liquidity layers is increasingly pronounced.

Third, large-scale zk technology application still requires time. Although zk Rollup is theoretically more secure and efficient, large-scale commercial deployment remains challenging due to complex proof generation processes and high computational costs.

<

Looking ahead, the Layer2 sector may exhibit the following trends:

• Deepened modular specialization: Execution, settlement, and data availability layers will further separate, with specialized division of labor enhancing efficiency.
• Enhanced interoperability: Cross-chain bridging and unified liquidity protocols will mature, making capital movement between Layer2s more convenient.
• Diversified application scenarios: Beyond DeFi, Layer2 will find differentiated positioning in gaming, social, and payment scenarios.
• Improved regulatory frameworks: As on-chain economic scale expands, Layer2 regulatory concerns will receive greater attention.

Conclusion

The one-year anniversary of the Dencun upgrade marks a pivotal transition for the Ethereum Layer2 ecosystem from "concept verification" to "scale application." The cost reduction brought by the Blob mechanism accelerated user adoption and ecosystem prosperity; modular technology evolution has paved the way for Layer2's long-term development.

However, the Layer2 sector remains in an early competitive phase. Topics such as technical route debates, decentralized governance, and liquidity integration await resolution. For investors and developers focused on the Ethereum ecosystem, understanding the historical significance and upcoming challenges of the Dencun upgrade will help better navigate the Layer2 sector's evolution trajectory.

Risk Warning: This article is for market research reference only and does not constitute any investment advice. The cryptocurrency market exhibits high volatility; investment requires caution, and decisions should be made based on individual risk tolerance.