Citation

Yang, S., Öz, B., Wu, F., Zhang, F. “Geographical Centralization Resilience in Ethereum’s Block-Building Paradigms.” Proc. ACM Meas. Anal. Comput. Syst. 10, 2, Article 39 (June 2026). doi:10.1145/3805637

Published: June 2026 (arXiv v3: Apr 5, 2026)

Core Claim

Ethereum’s block-building architecture is not geographically neutral. Both local building and external building (MEV-Boost) generate location-dependent payoffs and incentives to relocate, but through different underlying mechanisms. Asymmetric access to information sources amplifies centralization effects.

Methods

  • Formal mean-field model of validators’ geographic positioning incentives
  • Agent-based simulation calibrated with real-world latency data
  • Two block-building paradigms compared: local building vs. external building (MEV-Boost)
  • Varied: geographic distribution of validators, information sources, consensus parameters (attestation thresholds, slot time)

Key Findings

Under Local Block Building

  • Validators have incentive to co-locate near other validators (to receive blocks faster → better attestation rewards)
  • Validators also incentivized to move near information sources (CEX feeds, price oracles) for CEX-DEX arb
  • Creates two competing gravity wells: peer network vs. information sources
  • Result: moderate but persistent centralization, concentrated along low-latency corridors

Under External Block Building (MEV-Boost)

  • Block construction outsourced to builders; validators receive completed blocks via relays
  • Validator proximity to the relay replaces proximity to other validators
  • All major relays are US/EU → strong pull toward Atlantic corridor
  • Asymmetric access to builder infrastructure (co-location in datacenters) amplifies centralization
  • Different mechanism, similar outcome: centralization but geographically concentrated near relay/builder infrastructure

Effect of Consensus Parameters

  • Attestation threshold: higher thresholds increase latency sensitivity → more centralization pressure
  • Slot time reduction: halving slot time dramatically amplifies geographic effects; short slots benefit validators closest to relay/builder infrastructure
  • Protocol-level levers can mitigate or amplify geographic centralization

Asymmetric Information Access

  • Validators with privileged access to CEX price feeds (co-located with exchanges) have systematic advantage
  • This advantage amplifies centralization: only validators in specific regions can profitably engage in CEX-DEX arbitrage
  • Geographic information asymmetry → MEV income asymmetry → staking concentration

Implications for Protocol Design

  1. ePBS changes geographic incentives: with in-protocol PBS, builders’ location matters more than validators’. This may reduce validator geographic pressure but concentrate builder location
  2. Slot time reduction (Strawmap target: 8s → 4s) should be evaluated for geographic effects before deployment
  3. Decentralized building (BuilderNet, NAMP) reduces the geographic advantage of co-located builders
  4. Relay decentralization (geographic diversity) is necessary to reduce validator pull to US/EU

Connection to Existing Wiki