2 posts tagged with "congestion"

This week, the Leios team made significant progress in protocol development, focusing on improving simulation capabilities and analyzing protocol behavior under various network conditions. A comparison of Haskell and Rust simulations across 18 scenarios demonstrated that the Leios protocol scales effectively to mainnet-sized networks. However, congestion occurs when the input block rate reaches 30 IB/s.

Simulation comparison​

• Compared 18 scenarios between Haskell and Rust simulations at tag leios-2025w12
• Recent fixes and adjustments enabled meaningful comparison between simulations
• Identified differences when comparing the Haskell and Rust results, which are under active investigation.

Analysis of simulations​

• Completed the first simulation of Short Leios, evaluating IB production rate, IB size, and network topology
• Demonstrated that the Leios protocol scales effectively to mainnet-sized networks
• Identified congestion occurring when the input block rate exceeds 30 IB/s
• Suggested that allowing IBs larger than current Praos RBs may have advantages in TCP efficiency, network usage, and adapting to fluctuating transaction loads.

Peak CPU	Mean CPU

Haskell simulation​

• Implemented expiration of blocks:
  • Blocks are removed from the relay buffer once diffusion stops and cleared from other states as specified
• Developed an initial Full Leios implementation:
  • Currently in early testing
  • Added the praos-chain-quality configuration parameter for the \eta parameter from the specification.

Rust simulation​

• Developed an initial Full Leios implementation using estimated values for some parameters.

Formal methods​

• Short Leios trace verification: modeling local state evolution of a node
• Developed an initial trace verifier for Short Leios simulation traces in leios-trace-verifier.

This week in Leios development, CPS-0018 for transaction throughput was approved, along with improved Docker support for simulations and analysis of cross-simulation results. The team also examined input block (IB) production rates and their impact on network performance.

Protocol development​

• CPS-0018 'Greater transaction throughput' officially approved:
  • Merged into Cardano Foundation's CIP/CPS repository
  • Documents urgency of higher transaction throughput
  • Defines goals for the Leios initiative
  • Identifies key open questions and use cases.

Cross-simulation analysis​

• Conducted a comprehensive analysis of IB production rates ranging from 1 IB/s to 100 IB/s:
  • Developed an ELT workflow for data processing via MongoDB
  • Created an R Jupyter notebook for analysis and visualization
  • Identified and addressed three significant bugs (#207, #208, #209)
• Key findings from the Haskell simulation:
  • Network congestion emerges at high IB production rates
  • Both average propagation time and slow propagation tail increase
  • A critical threshold of ~40 IBs/s was identified, beyond which network congestion severely impacts block reception
• Comparison of PeerNet and Haskell simulations:
  • Both exhibit qualitatively similar block propagation distributions
  • Both demonstrate protocol breakdown under high block production rates
  • Differences in resolution and configuration prevent exact comparison.

Infrastructure improvements​

• Added comprehensive Docker support for both simulations:
  • Optimized multi-stage Docker files for Haskell and Rust
  • Simplified deployment process
  • Enabled easy configuration via volume mounts and parameters
  • Documented usage in README.md.

Rust simulation​

• Enhanced Rust simulation capabilities:
  • Implemented bandwidth usage tracking
  • Added configurable bandwidth limits per connection
  • Fixed issues identified in cross-simulation comparisons
  • Started updating visualizations for improved clarity.

Haskell simulation​

• Enhanced IB sortition handling for IB/slot < 1
• Began integrating block expiration and diffusion-halt proposal
• Implemented ideal timing calculations for diffusion:
  • Added uniform block behavior configuration
  • Identified relay mini-protocol complexities:
    • Variable latency (3-4) for block transfer
    • Latency depends on traffic conditions and request handling.

Formal methods​

• Moved formal specification to a dedicated repository
• Established a conformance testing framework:
  • Enabled testing between Short Leios implementations
  • Documented the test suite execution process
• Initiated a survey of network models across IO consensus projects.