4 posts tagged with "cip"

This week, the Leios team advanced the Cardano Improvement Proposal (CIP) documentation, conducted comprehensive attack analysis experiments, and continued cross-validation between simulation implementations. The team successfully demonstrated resilience characteristics of proposed Leios under adversarial conditions and refined protocol specification components for the formal CIP submission.

CIP development progress​

The team made substantial progress on the Ouroboros Leios CIP proposal. The draft specification section is now complete except for the network and incentives components. The motivation and abstract sections have been refined for clarity, enhancing the document's accessibility and technical precision. The first of four main rationale subsections has been fully drafted, providing evidence-based arguments for the necessity and viability of the proposed Leios protocol enhancement.

Attack resistance analysis​

Initial adversarial simulation experiments​

The team conducted the first simulation experiment for attacks, examining late Endorser Block (EB) and transaction diffusion scenarios where adversaries control timing of critical protocol messages. The experiment varied the diffusion parameter L_diff and EB propagation schemes to assess protocol robustness under different adversarial strategies.

Key findings from the initial attack analysis include successful demonstration that late-release attacks can impact proposed Leios throughput under specific conditions. The analysis revealed that transaction loss occurred in some scenarios due to memory pool rule formulations in the simulator, leading to important insights for protocol hardening and implementation requirements.

Cross-simulation validation​

Haskell versus Rust comparison​

The team completed another comprehensive comparison between Haskell and Rust simulation implementations at analysis/sims/202532b. Results indicate successful resolution of previous discrepancies in vote diffusion behavior between the two simulation environments. This validation ensures both implementations produce consistent results for protocol analysis and strengthens confidence in the simulation-based evidence supporting the CIP.

CIP figure preparation​

The experiment for draft figures for CIP progressed with updated simulation runs designed to generate publication-quality performance charts and protocol behavior visualizations for inclusion in the formal CIP documentation.

Next steps​

• Complete the remaining network and incentives sections of the CIP specification
• Conduct follow-up analysis on attack experiment findings to refine protocol parameters
• Continue refinement of memory pool rules based on adversarial scenario insights
• Finalize CIP figures and supporting analysis for submission preparation.

This week, the Leios team made significant progress on the Cardano Improvement Proposal (CIP) documentation, conducted extensive Plutus validation experiments, and resolved outstanding discrepancies between simulation implementations. The team successfully demonstrated Linear Leios performance under various Plutus workloads and completed comprehensive protocol parameter analysis for CIP inclusion.

CIP development progress​

The team completed substantial portions of the Leios CIP draft, bringing it closer to submission readiness. The specification section is now complete except for network and incentives components, with the motivation and abstract refined for clarity. The first of four main rationale subsections has been fully drafted, providing evidence-based arguments for Leios necessity and viability.

Plutus validation experiments​

The team conducted comprehensive experiments examining Linear Leios performance under varying Plutus computation loads using 6-vCPU nodes at 100 TPS. Key findings from the Plutus validation analysis include:

• Linear Leios successfully supported doubling the Plutus per-transaction budget
• Protocol breakdown occurred at sixfold increases in Plutus budgets due to validation bottlenecks
• Endorser blocks could handle approximately 5,000 execution steps of Plutus computation, representing 250 times the current Praos per-block budget
• This capacity could support either a handful of transactions with 20x greater Plutus budgets or increasing every Plutus transaction budget by 50%
• Late diffusion of Plutus-heavy transactions poses potential risks to EB adoption timing.

The analysis revealed significant variability in CPU time requirements for Plutus scripts relative to their execution steps, highlighting the need for careful resource planning in high-throughput scenarios.

Simulation improvements and comparisons​

Cross-simulation validation​

The team completed another comprehensive comparison between Haskell and Rust simulations at analysis/sims/202532b, successfully resolving previous discrepancies in vote diffusion behavior. This validation ensures both simulation implementations produce consistent results for protocol analysis.

Protocol parameter optimization​

The 2025w32 experiment established a comprehensive set of protocol parameters and throughput scenarios for inclusion in the CIP Evidence section:

• Protocol variant: Linear Leios with conservative resource allocation
• Resource requirements: 4 vCPU per node, 10 Mb/s bandwidth
• Stage configuration: 7 slots each for voting and diffusion stages
• Block limits: Maximum 12 MB transaction references per EB
• Transaction size: 1,500 bytes per transaction with normal Plutus frequency

Key performance findings demonstrate that modest computational resources adequately support throughput up to 0.3 TxMB/s, with 7-slot stages providing sufficient diffusion time while minimizing EB discard probability. The 12 MB EB limit allows occasional peak utilization to compensate for unlucky sortition periods.

Implementation enhancements​

Haskell simulation​

The team addressed head-of-line blocking issues in Linear Leios by implementing message slicing capabilities in the mini-protocol multiplexer, eliminating unexpected delays in vote diffusion. Additional work focused on developing new mini-protocols for enhanced Linear Leios simulation fidelity, with ongoing refinements to balance protocol granularity and sophistication.

Rust simulation​

Implementation of transaction withholding attack scenarios for Linear Leios, where EB producers delay transaction publication until EB release. The simulation also received updates to improve handling of late transactions, EBs, and RBs in Linear Leios scenarios.

Next steps​

• Complete remaining network and incentives sections of the CIP specification
• Finalize mini-protocol designs for enhanced simulation accuracy
• Continue investigation of mempool rule adequacy for high-throughput scenarios
• Expand Plutus validation analysis to cover additional execution budget scenarios.

This week, the Leios team made significant progress in protocol documentation, simulation improvements, and transaction lifecycle analysis. The team completed a draft of the Leios CIP, enhanced simulation visualization capabilities, and conducted detailed analysis of transaction processing times in Full Leios.

Simulation and analysis​

• Completed simulation of 270 Full Leios scenarios at tag leios-2025w17
• Resolved all outstanding discrepancies between Rust and Haskell simulation results
• Conducted detailed transaction lifecycle analysis:
  • Average IB inclusion time: 2.4 seconds
  • Average EB referencing time: 27.6 seconds
  • Average RB referencing time: 67.2 seconds
  • Identified issues with transaction referencing and duplication in current Full Leios implementation.

Protocol documentation​

• Drafted major sections of the Leios CIP using standard CIP template
• Documented evidence-based arguments for Leios necessity and viability
• Pending completion of Full Leios protocol sections due to ongoing discussions.

Rust implementation​

• Publicly hosted visualization as part of the Leios documentation
• Added new "transactions" view showing transaction state graphs over time
• Fixed stability issues in long-running simulations
• Implemented leios-late-ib-inclusion extension for referencing older pipeline IBs.

Plutus benchmarking​

• Documented workflow for benchmarking Plutus
• Prepared methodology for potential experiments with increased Plutus execution budgets
• Established framework for relating Plutus execution units to CPU time measurements.

Next steps​

• Address transaction referencing and duplication issues in Full Leios
• Complete remaining Full Leios protocol sections in CIP
• Investigate higher transaction rates after resolution of #305
• Continue monitoring and optimizing transaction lifecycle performance.

This week in Leios development, the team focused on simulation analysis, formal methods, and documentation updates. Key accomplishments include in-depth analysis of simulations at tag leios-2025w10, advancements in formal methods through a working trace verifier, and the development of technical reports.

Cross-simulation analysis​

• Completed a comprehensive analysis of simulations at tag leios-2025w10:
  • Analyzed Haskell simulation performance with and without CPU usage considerations
  • Varying key protocol parameters:
    • IB production rate
    • IB size
    • Length of Leios stages
  • Identified the following aspects of Leios:
    • Delay between IB generation and receipt at nodes
    • Peak and mean CPU usage over time
    • Breakdown of CPU usage by task type
    • Sizes of IBs, EBs, and RBs
    • Duplicate IB references in EBs
    • Reference to EBs from RBs
    • Resource utilization in network traffic.

Protocol and formal methods​

• Began developing a trace verifier in Agda:
  • Implemented event trace parsing using the Haskell module leios-trace-hs.

Documentation and research​

• Completed the full draft of the Leios technical report #1
• Created a skeletal draft of the Leios CIP
• Aligned with the latest CIP template
• Developed a detailed simulation analysis for the 100-node Leios network.

Programming and testing​

• Resolved several simulation issues:
  • #235: RB size does not reflect the presence of a certificate
  • #234: Fast transmission of large blocks at moderate IB rate
  • #232: Monotonicity of EB inclusion in RBs
  • #230: EBs are not large enough to include their IBs
  • #229: Rust simulations panics from overflow
• Enabled the visualization of network traffic and logging messages for multiple predefined 'scenarios' instead of a single hard-coded trace
• Updated the visualization to display resource utilization in network traffic.

Rust simulation visualization​

• Improved visualization capabilities:
  • Added support for multiple predefined 'scenarios' instead of single hard-coded trace
  • Moved the visualization logic to the client-side web worker for better performance
  • Added the visualization of per-node network traffic breakdown by message type
• Fixed critical simulation bugs:
  • Resolved issue #229 causing time travel and crashes in high-traffic high-latency scenarios.