Executive Summary
The Story So Far
Why This Matters
Who Thinks What?
Ethereum’s second major upgrade of the year, dubbed “Fusaka,” is scheduled to activate on the blockchain’s mainnet on December 3, 2025. This significant update aims to drastically improve the network’s capacity to manage the growing transaction traffic from its layer 2 chains, which collectively represent a $47 billion on-chain economy built atop Ethereum’s base layer.
Key Upgrade Details
The primary objective of Fusaka is to enhance data availability through a key feature called PeerDAS, which is expected to make rollups both cheaper and more scalable. Nick Johnson, founder and lead developer of Ethereum Naming Service (ENS), emphasized that PeerDAS will have the biggest impact on these improvements.
Layer 2 chains currently bundle thousands of transactions into summaries, known as blobs, and submit them to the Ethereum base layer. Nodes on the base layer must download the entire blob data to verify validity, a process that becomes increasingly expensive and creates data traffic jams as layer 2 transactions surge.
PeerDAS addresses this challenge by reducing the data load required for nodes to verify layer 2 transactions. Instead of downloading the complete blob, nodes will only need to check random samples within the blob data, significantly streamlining the verification process.
Expert Perspectives
Leo Fan, co-founder of zero-knowledge-based blockchain Cysic, described Fusaka as a “deep infrastructural shift” for Ethereum, projecting that it could increase the chain’s throughput eightfold. Shiv Shankar, CEO of Boundless, a zero-knowledge scalability protocol, added that this reduction in bandwidth costs for nodes will improve Ethereum’s overall efficiency, benefiting developers building applications.
Fusaka encompasses a total of 12 Ethereum Improvement Proposals (EIPs), which are vetted blueprints for blockchain changes. These EIPs include two upgrades specifically designed to stretch the base layer’s block and data limits, thereby increasing transaction processing capacity and the number of blobs layer 2 chains can submit.
Ethereum’s Scaling Roadmap
This upgrade marks the latest step in Ethereum’s ambitious development roadmap, which seeks to scale the $410 billion blockchain to handle 100,000 transactions per second, a substantial leap from its current maximum of 30 transactions per second. It follows the “Pectra” upgrade, which was released by developers in May.
Looking Ahead
The Fusaka upgrade represents a critical milestone in Ethereum’s ongoing efforts to enhance its scalability and efficiency. By optimizing data handling for layer 2 transactions and increasing base layer capacities, Ethereum aims to solidify its foundation for future growth and broader adoption within the decentralized finance ecosystem.
