[CONSTITUTIONAL] AIP: Update Arbitrum One and Nova L1-Pricing Parameters for Ethereum Glamsterdam

Proposals
1

[CONSTITUTIONAL] AIP: Update Arbitrum One and Nova L1-Pricing Parameters for Ethereum Glamsterdam

Abstract

This proposal updates the parentGasFloorPerToken and perBatchGasCharge parameters on Arbitrum One and Arbitrum Nova in response to Ethereum’s Glamsterdam upgrade.

Glamsterdam changes the Ethereum gas costs associated with posting Arbitrum chain batches. Without corresponding parameter updates, the L1 fee paid by Arbitrum One and Nova users may no longer accurately reflect the cost of posting batches to Ethereum.

The proposal authorizes targeted updates to the live parameters through the ArbOwner precompile. It does not introduce an ArbOS software upgrade or change the underlying L1-pricing algorithm.

Motivation

Arbitrum’s L1-pricing system estimates Ethereum gas cost of each batch, then uses that estimate to set the L1 fee paid by Arbitrum users and the amount the batch poster is paid back. Two parameters feed into this estimate:

  • parentGasFloorPerToken, which mirrors Ethereum’s minimum gas charge for calldata; and
  • perBatchGasCharge, which represents a fixed component of the estimated Ethereum gas cost attributed to each batch.

The existing values reflect Ethereum’s pre-Glamsterdam cost structure. Following Glamsterdam’s activation, they may no longer accurately account for the costs incurred by the Arbitrum One and Nova batch posters.

This proposal updates the parameters to reflect the expected post-Glamsterdam posting costs.

Rationale

Updating these two parameters is the smallest change that keeps the L1 fee paid by Arbitrum users in line with what the batch posters spend after Glamsterdam. It uses the existing ArbOwner controls and requires no change to Nitro software, ArbOS or the L1-pricing algorithm.

The proposed values are based on measured post-Glamsterdam batch costs. They may be revisited if posting costs or the L1-pricing system changes.

Specifications

Affected chains

This proposal applies to:

  • Arbitrum One; and
  • Arbitrum Nova.

It does not change parameters on Arbitrum Sepolia or independently governed Arbitrum chains.

Parameter updates

Parameter Current value Proposed value
parentGasFloorPerToken 10 16
perBatchGasCharge 210,000 480,000

Note: these values may underestimate the gas paid for zero-bytes posted for calldata. The effect is minimal, since zero bytes are rare and Arbitrum One and Nova post blobs. A future ArbOS version could address this.

For each chain, the Governance Action Contract will call:

ArbOwner.setParentGasFloorPerToken(16);
ArbOwner.setPerBatchGasCharge(480000);

The proposal also includes an onchain check (GlamsterdamForkGateAction) that blocks execution until Glamsterdam is live on Ethereum. Any earlier attempt reverts, and the proposal can only be executed once the fork is active.

Implementation work is available in ArbitrumFoundation/governance PR #384.

Expected Impact

If approved and executed, the proposal is expected to improve the alignment between:

  • The Ethereum gas costs incurred by the Arbitrum One and Nova batch posters after Glamsterdam; and
  • The reimbursement calculated by the existing ArbOS L1-pricing system.

Updating these parameters will affect the L1 fee component paid by users.

The proposal does not change Nitro node software, transaction-execution rules or the ArbOS version running on either chain.

Steps to Implement

  1. Forum discussion: An AIP outlining the proposed parameter changes is posted to the ArbitrumDAO Forum for discussion (this post).
  2. Temperature check: Submit the proposal to Snapshot.
  3. Implementation and review: The governance payload is finalized, tested and audited by a third party. The audit report, source code and deployment addresses are published before the onchain vote.
  4. Onchain vote: Following a successful temperature check and completion of the implementation materials, submit the Constitutional AIP for an on-chain vote.
  5. Governance execution: If approved, complete the required governance waiting periods and execute the proposal once Glamsterdam is active on Ethereum.

Overall Cost

This proposal comes at no additional cost to the ArbitrumDAO; the engineering work and coordination for an audit will be managed by Offchain.