Bankless: What is the Blob of EIP4844 in the Cancun Upgrade?

Original Title: 《WTF is a Blob?》

Original Author: 563

Compiled by: Kate, Marsbit

Recently, we've been discussing the increasing number of Blobs on Bankless, and if you're still a bit confused about them, we won't blame you. Well, we're here today to give you a refresher on Ethereum's recent roadmap. Today, 563 will dive into blobspace and tell us that it's not a big deal. ------Bankless Team

If you've been following cryptocurrency throughout the bear market, you might have heard about Ethereum's "rollup-based" roadmap. With EIP-4844, the Ethereum mainnet has helped these scaling solutions by introducing the new concept of blobs.

Yes, blobs.

But what does a "blob" mean, and how does it help Ethereum's long-term plan for scaling through rollups? Let's get started.

From Full Execution Sharding to Rollup

So, sharding involves randomly rotating validators in different shards (subgroups) of the blockchain, with each shard essentially being its own mini-blockchain running in parallel with the beacon chain.

This isn't a new idea in network design; running a bunch of parallel processes has been part of Ethereum's plan for a long time.

The only question is, what? It's a complex change and takes too long. While Ethereum developers and researchers are figuring out how to best implement sharding, a new challenger has emerged—rollup.

Rollup doesn't break the Ethereum main chain into its own mini-blockchains; instead, it acts as a mini-blockchain that runs "on top of" Ethereum's Layer 1 (hence called Layer 2). When Vitalik wrote his "rollup-centric Ethereum roadmap" in 2020, it was already written:

"In my opinion, when (full execution sharding) finally arrives, basically no one will care about it. Whether we like it or not, everyone has already adapted to a rollup-centric world, and by then, it will be easier to continue down this path than to try to get everyone back on the base chain, as there are no obvious benefits, and scalability is reduced by 20-100 times."

Why EIP-4844 is a Game Changer

Now that the Ethereum community has overwhelmingly embraced rollup as the future, what improvements can have the most significant impact on the mainnet?

First, let's briefly outline the responsibilities of the blockchain in the Ethereum-rollup relationship.

Ethereum's original sharding-centric vision was to scale execution on the mainnet. Now, with execution scaling via rollup, this is no longer a priority.

How Ethereum and rollup function in a modular blockchain architecture.

What else is the issue today? Data availability.

Rollup still needs to publish transaction data (as well as fraud/validity proofs for settlement verification) back to L1 so that everyone has a complete understanding of what’s happening across the network. Currently, this is an expensive gamble.

Thus, while rollup helps scale execution, Proto-Danksharding (PDS, with EIP-4844) is expected to help scale data availability through blobs.

You can think of blobs as a new type of tool where rollups can efficiently store transaction and proof data, saving gas when sending this information to the mainnet. This new type of transaction provides a better way for L2 to interact with L1 block space.

A diagram outlining the blob transactions introduced by EIP-4844. Note that DAS will only be available with full Danksharding.

While the actual gas savings from EIP-4844 will depend on the adoption of blobs, rough preliminary estimates show that cumulative transaction costs could increase by 10-100 times.

Is it just a few cents to transact on Ethereum L2? Yes, please.

In fact, these fees could be very cheap, and they could be fully subsidized by L2 sequencers looking to create some buzz in their networks. Given that both Arbitrum and Optimism are already running token incentive programs, this isn't a crazy idea. Who wouldn't want to trade for free?

The Great Decoupling

After the PDS update in EIP-4844, validators on the Ethereum mainnet will be able to handle L1 execution and blobs (containing L2 data and settlement/proofs). What's the best part? For the first time, we will have independent fee markets for these two sets of data.

Before EIP-4844, L1 gas fees directly impacted the gas costs of rollup.

After EIP-4844 = the fee markets for L2 blobs and L1 execution are completely decoupled.

The decoupling of fee markets is a major reason why Visa chose Solana as the network for stablecoin payments.

Overhyped NFT minting on the Ethereum mainnet will no longer affect the rollups favored by DeFi users. With independent fee markets, these unnecessary entanglements will become a thing of the past.

Blobs will also inherit a "target allocation," where each block can contain three blobs. Like EIP-1559, blob fees are saved through a running count to ensure that blobs do not congest the network. In this way, blobs and L1 execution transactions can coexist harmoniously on the base chain.

What Happens Next

EIP-4844 is expected to launch alongside Ethereum's next upgrade, Dencun, possibly in January. After the mainnet update, rollups will need to make some upgrades to properly construct blobs and send them to the mainnet.

Due to its complexity, full sharding (FDS) is further down the Ethereum roadmap, but it will introduce massive upgrades:

• Data Availability Sampling (DAS) — nodes do not have to download the entire dataset to confirm the existence of data. They only need to randomly sample (called "data availability checks").

• Blocks will be able to contain more blobs, and blobs can be larger, thanks to DAS.

What's the best part? Once FDS arrives, rollups will not need upgrades to support it—they only need the upgrade from EIP-4844.

With the rollout of proto-danksharding, the rollup-centric roadmap officially begins, laying the groundwork for the next chapter of Ethereum. So, when you enjoy nearly free transactions on your favorite L2 next summer, remember to thank your friendly neighbor.