Author: Tanay Ved Source: coinmetrics Translation: Shan Oppa, Bitcoin Vision

core points

• Fusaka builds a more efficient data availability system by increasing blob capacity and deploying node PeerDAS, greatly expanding Ethereum’s expansion capabilities.

• The 60 million Gas limit increase and execution layer optimization significantly improve L1 throughput.

• The optimized fee mechanism and user experience upgrade lay the foundation for a more unified and cost-effective L1-L2 ecosystem.

Fusaka upgrade overview

Ethereum will undergo its next upgrade at 9:49 pm on December 3, 2025 (UTC time, time slot 13,164,544). This hard fork is named “Fusaka”.Following the naming convention of previous forks, the Fukasaka upgrade integrates the execution layer “Osaka” upgrade and the consensus layer “Fulu” upgrade.

Following the Pectra upgrade in May, the Fusaka upgrade is an important step in Ethereum’s expansion roadmap. It will improve network performance, expand data block capacity, improve Rollup cost-effectiveness, and optimize user experience.The upgrade also introduces the “Block Parameters Only (BPO)” forking mechanism, which can safely increase the data block capacity as Rollup demand grows.Earlier this year, the Ethereum Foundation announced its “protocol” strategy, which revolves around three long-term goals: layer-1 network expansion, data block expansion and user experience optimization.The Fukasaka upgrade is the first upgrade that fully fits this unified vision, marking an inflection point in Ethereum’s plans to expand capacity and improve accessibility.

This article will break down the key changes in the Fusaka upgrade in detail, as well as the expected impact on the Ethereum mainnet, second-layer rollup, transaction costs and user experience after the upgrade is activated.

Data block expansion

Last year’s Dencun upgrade introduced “blobs,” a cost-effective way for rollups to store transaction data on the Ethereum mainnet.Since then, blobs have become widely used thanks to rollup projects such as Base, Arbitrum, and Lighter.This often leads to blob usage approaching saturation (currently close to the target of 6 blobs per block), thereby increasing the risk of exponential growth in rollup fees.Higher data availability (DA) requirements make blobs space a key bottleneck for Ethereum expansion, and Fusaka is a solution proposed to solve these limitations.

PeerDAS: Peer Data Availability Sampling

PeerDAS (EIP-7594), or Peer Data Availability Sampling, is arguably one of the most important upgrades in the Fusaka release, and it directly aligns with the goal of extending L1 consensus and blob data.PeerDAS provides a more efficient way for Ethereum nodes to check the availability of blob data.Instead of downloading the entire contents of the blob, nodes verify the data’s availability by sampling a small amount of the data, providing the same security guarantees without increasing the burden on L1 consensus nodes.

Expected impact:

• Nodes store only about 1/8 of each block, allowing for higher block throughput without increasing hardware requirements.

• Enables Ethereum to safely increase blob throughput, a core driver of rollup capacity.

• Lower data availability costs reduce L2 transaction costs and increase the reliability of batch postings.

• This lays the foundation for comprehensive sharding of the entire ecosystem and higher overall transaction throughput.For example, Base said in a blog post that Fusaka L2 scaling improvements will allow it to “double chain throughput in 2 months.”

Branch containing only Blob parameters (BPO)

Because PeerDAS reduces the bandwidth and storage required for nodes to validate blob data, Ethereum can now safely increase blob capacity.Fusaka introduced a blob parameter only (BPO) fork designed to increase the number of blobs per block over time.This allows Ethereum to adjust blob parameters without waiting for a complete hard fork, giving the protocol a more flexible and responsive scaling tool.

Upcoming BPO branches:

Expected impact:

• Increase DA bandwidth:Increase rollup capacity from 6 to 128 blobs per block and reduce L2 transaction fees.

• Flexible expansion:blob parameters can be dynamically adjusted as demand grows.

• Step-by-step development path:Consistent with Ethereum’s roadmap to reduce rollup execution costs and enable scalable data availability.

Blob base fee adjustment

As blob capacity expands, Ethereum’s blob fee market will play a greater role in coordinating rollup demand.Currently, Rollup costs almost nothing to obtain blobs.Since demand is relatively insensitive to price and prices do not always adapt smoothly to changes in usage, Blob fees are typically kept at a minimum of 1 wei.This causes the fee mechanism to be in a “price inelastic” range, limiting its ability to respond to changes in usage.

Source: Ethereum EIP 7198

Fusaka introduces a floor on the blob base fee by tying the blob base fee to a portion of the L1 base fee.This prevents blob prices from plummeting to zero and ensures that the fee adjustment mechanism continues to work effectively as the blobspace scales.

• More stable volume pricing:Prevent the fee market from falling into the trap of the lowest price.

• Predictable aggregate economic benefits:Ensure aggregation pays a reasonable baseline fee for data availability without sudden or erratic fee increases.

• Minimal impact on user costs:Even with the new lower limit, L2 data costs are still only a fraction of a cent, with minimal impact on user experience.

• Sustainable long-term economic benefits:To compensate for the increased blob throughput processed by nodes, blob fees currently contribute a small amount to ETH burning and may contribute more in the future as capacity expands.

L1 expansion

Fusaka also attaches great importance to L1 expansion.He improved Ethereum’s Layer-1 execution capabilities through EIP-7935, raising the protocol’s default gas limit to 60M.This directly increases the number of transactions that can be accommodated per block, resulting in higher throughput, less congestion, and lower gas fees.

Data source: Coin Metrics Network Data Pro

Expected impact:

• Higher throughput:The greater the amount of computation per data block, the greater the overall L1 capacity.

• Support for more complex applications:Larger gas limits allow for the execution of complex contracts.

• Congestion reduction under load:The extra headroom reduces congestion during peak demand periods.

• Help keep fees low:The additional capacity will help maintain current low fee levels (<0.4 gwei).

Data source: Coin Metrics Network Data Pro

In addition to increasing the gas limit, Fusaka has also introduced improvements to improve L1 execution efficiency and prepare the network for future expansion.The new per-transaction gas usage cap prevents any single transaction from dominating a block and sets the stage for parallel execution.Updates to ModExp precompilation recalibrate gas costs and set clearer boundaries for operations, keeping resource usage predictable while throughput grows.In addition, the network layer has been simplified by removing obsolete pre-merge fields, making synchronization of Ethereum nodes faster and more efficient.

Improve user experience

Fusaka has also introduced several updates aimed at improving ease of use for users and developers.EIP-7951 adds native support for secp256r1 elliptic curves, the signature standard used by Apple Secure Enclave, Android Keystore, and most consumer hardware.This enables wallets and applications to integrate familiar authentication flows (Face ID, Touch ID, WebAuthn) directly on Ethereum, thereby lowering the barrier to user registration and enhancing security for retail and institutional users.

These upgrades help modernize Ethereum developer and user interfaces, making it easier to build secure, mainstream applications.

Summary

After the Fusaka upgrade is activated, the most direct impact will be reflected in the reduction of rollup fees, increase in data block throughput, and significant expansion of the execution capacity of the first-tier network.In the long term, larger data block space, lower costs, and steady improvements in layer-1 network performance will jointly shape the economic model of layer-2 settlement, affect ETH burning dynamics, and make the entire Ethereum ecosystem more collaborative and unified.

While the long-term value impact will ultimately depend on demand and adoption, the Fukasaka upgrade lays out a clearer, more scalable foundation for the next phase of Ethereum’s growth—a foundation in which layer one and layer two networks will operate more seamlessly together, and the network will be more capable of supporting more users, assets, and on-chain activities.