Celestia: The Shwap Upgrade, Path to 1GB Blocks

Oct 22, 2024

The Celestia ecosystem is rapidly evolving with two groundbreaking developments: the Shwap upgrade and Mammoth Mini testnet. These innovations mark significant progress toward the community's ambitious goal of reaching 1GB blocks, promising unprecedented scalability for blockchain applications.

Shwap: The Foundation for Scale

Celestia's data availability (DA) network recently received its first major upgrade with Shwap - now live on Arabica and Mocha testnets with celestia-node v0.18.2. The upgrade delivers impressive improvements, making DA sampling 12x faster while reducing storage requirements by 16.5x.

The previous DA network architecture, while functional, faced fundamental scalability limitations. Built during the Devnet era, it relied on an IPLD-based protocol that followed a common pitfall in blockchain engineering: hash-addressability. While this approach initially seemed promising, offering features like deduplication, it introduced significant inefficiencies.

For instance, under the old system, light nodes needed to make seven blocking round-trips just to verify a single sample in a 128x128 data square. This process required multiple network requests and IO reads on the full node side, while also maintaining a resource-heavy global index of historical Merkle Tree nodes.

Shwap addresses these limitations through three key innovations:

  1. A reimagined data square storage subsystem
  2. A composable networking framework
  3. O(1) data availability sampling

The results are remarkable: full node sync times have been reduced from 7 days to just 8 hours on the Mocha testnet. Light nodes see even more dramatic improvements, with sync times dropping from 24 hours to 2 hours.

Mammoth Mini: A Glimpse into the Future

While Shwap lays the groundwork, the recently unveiled Mammoth Mini testnet showcases what's possible with these optimizations pushed to their limits. This proof-of-concept network implements 88MB blocks with an average throughput of 27MB/s - a staggering 160x increase from Celestia's launch throughput of 0.167MB/s (2MB blocks every 12 seconds).

Mammoth Mini combines several cutting-edge improvements:

Compact Blocks

Drawing inspiration from BIP-152, compact blocks eliminate redundant data transmission. Instead of broadcasting entire blocks, nodes share transaction identifiers for data already present in their mempools. This dramatically reduces bandwidth requirements and enables effective pre-downloading of blocks outside of consensus.

Vacuum! Protocol

To ensure compact blocks work effectively, the new Vacuum! protocol introduces Validator Availability Certificates (VACs). These signed commitments to mempool transactions allow validators to coordinate pre-consensus, ensuring synchronized high-priority transactions. The protocol intelligently distributes download responsibilities across different peers, maximizing synchronization speed.

Fast Blocks Slow Squares (FBSS)

Mammoth Mini simulates the upcoming FBSS architecture, which decouples block construction from square construction. This separation allows for faster block times without compromising sampling efficiency, paving the way for sub-second block times with single-slot finality.

Real-world Impact

These improvements enable new possibilities for blockchain applications. Mammoth Mini's throughput alone could support hundreds of thousands of ERC-20 transfers per second (with compression) - comparable to running multiple Visa-scale payment networks in parallel. This capacity opens doors for:

  • High-performance sequencers
  • Alt-VM L2s that rival L1 throughput
  • Fully on-chain worlds
  • Verifiable web applications

The Road Ahead

While Shwap is scheduled to reach Mainnet Beta in November 2024, Mammoth Mini's innovations are targeted for mainnet deployment throughout 2025. The Celestia core developer community is focused on iterative improvements to these systems, particularly the Vacuum! protocol and QUIC-based p2p stack.

These developments represent more than just performance improvements - they're foundational changes that enable Celestia to scale without requiring major protocol rewrites. With Shwap providing the architectural foundation and Mammoth Mini demonstrating the potential, Celestia is well-positioned to achieve its goal of 1GB blocks and beyond.

The path to truly scalable blockchain infrastructure is becoming clearer, and with each upgrade, Celestia moves closer to making it a reality. For developers interested in contributing to this journey, the community welcomes participation through the Celestia Forum, GitHub, or direct engagement on Twitter.