3 posts tagged with "topology"

This week, the Leios team made significant progress across multiple areas. Major developments included detailed DeltaQ analysis of network topologies, extensive BLS cryptography benchmarking, and improvements to both simulations. The team also explored succinct schemes for BLS key registration and conducted a detailed certificate performance analysis. Both Haskell and Rust simulations received substantial updates to improve visualization and support more realistic testing conditions.

DeltaQ analysis​

• Enhanced the topology-checker with ΔQSD analysis capabilities:
  • Extracts inter-node latencies from given topologies
  • Classifies latencies into near/far components
  • Builds parameterized ΔQ models
  • Outputs fitted models in delta_q web app syntax
• Key findings from topology analysis:
  • Clear distinction between near/far components in examined topologies
  • Unexpectedly high hop counts in latency-weighted Dijkstra paths:
    • Min 4-5, max 8 for topology - 100
    • Min 8, max 20 for 'realistic' topology
  • Model fitting achieved rough shape matching but showed significant deviations at low latencies
  • Resource usage tracking goals remain unmet due to complexity in understanding load multiplication factors.

BLS cryptography​

• Completed comprehensive benchmarking of certificate operations:
  • Detailed performance analysis across committee sizes (500-1000 seats)
  • Certificate generation: 63.4ms - 92.5ms
  • Certificate verification: 104.8ms - 144.9ms
  • Certificate weighing: ~12ms consistently
• Explored succinct schemes for key registration:
  • Proposed 90-day key evolution with 124-byte KZG commitments
  • Analyzed message sizes for key opening (316 bytes per pool)
  • Investigated SNARK-based alternatives for proof of possession
• Added BLS crypto to the CI pipeline with automated testing
• Documented parallelization strategies for certificate operations.

Formal methods​

• Added a conformance testing client for the executable Short Leios specification
• Successfully merged the executable specification for Simplified Leios into main.

Haskell simulation​

• Updated configuration defaults for block sizes and timings
• Added support for idealized simulation conditions:
  • Single-peer block body requests
  • TCP congestion window modeling
  • Mini-protocol multiplexing
  • Unlimited bandwidth links support
• Enhanced simulation output and analysis:
  • Added raw field for accumulated data
  • Implemented block diffusion CDF extraction
  • Created multi-CDF plotting capabilities.

Rust simulation​

• Enhanced visualization capabilities:
  • Added block size breakdown display
  • Implemented total bytes sent/received tracking
  • Added total TX count and CPU time metrics
• Improved event handling:
  • Updated to standard timestamp format (seconds)
  • Enhanced CPU task event structure
  • Added CBOR output support
• Added support for multiple strategies:
  • Implemented ib-diffusion-strategy (freshest-first, oldest-first, peer-order)
  • Added relay-strategy affecting TXs, IBs, EBs, votes, and RBs
  • Enabled unlimited EB and vote bundle downloads from peers.

The Leios team continued refining Haskell and Rust simulations, standardizing inputs, outputs, and event logging for better comparability. The team defined standard formats for configuration parameters and network topology for running the Leios protocol. They also worked on logging identical simulation events to compare and feed them into the DeltaQ model and, consequently, the executable specification, ensuring alignment with formal methods.

Haskell simulation updates​

• The short-leios simulation now outputs diffusion latency data
• Added support for different input block (IB) diffusion strategies:
  • freshest-first: higher slot numbers requested first
  • peer-order: requested in order of peer announcement
• Added support for Vote (Send) and Vote (Recv) stages.

Rust simulation progress​

• Added an 'organic' topology generator that better matches mainnet topology
• The generator creates clusters of colocated stake pools and relays
• The simulation uses stake to determine relay connectivity
• Topology insights gathered from stake pool owners:
  • Most pools have multiple relays (2,312 relays across 1,278 pools)
  • Pool operators often run multiple colocated pools sharing relays
  • Relays typically maintain ~25 active outgoing connections
  • Incoming connections scale with stake weight (10-400+ connections).

DeltaQ update​

• Wrote a comprehensive 2025-01 report covering work since September 2024.

Formal methods​

• Finalizing executable specifications for simplified and short Leios
• Extracted short Leios specification to Haskell for conformance testing.

Simulation progress​

Haskell implementation​

• Enhanced parameter handling with support for reading configurations and topologies from disk
• Added a new generate-topology command for random topology generation
• Aligned Leios sortition with algorithms from sortition benchmarks and the technical report
• Completed analysis comparing the Praos simulation with the benchmark cluster
  • Adoption times within 10% of measured values
  • Review of simulation parameters pending
• Next steps identified:
  • Generate topologies with block producers behind relays
  • Begin comparison with the idealized diffusion model
  • Configure and run simulations for higher throughput.

Rust implementation​

• Completed the first pass of block-level visualization
• Updated topology files to include baked-in latencies
• Improved output with human-readable names from the shared topology format
• Enhanced simulation output comparability across different simulations.

Analysis and research​

Sortition analysis​

• Completed a detailed analysis of the 'Fiat Accompli' sortition scheme using mainnet stake distribution (Epoch 535)
• Key findings for 500-vote committees:
  • 406 largest stake block-producers would be deterministic voters
  • ~88 voters would be randomly selected
  • Significant certificate size reduction achieved through deterministic voter selection.

Downstream impact assessment​

Started comprehensive analysis of Leios's impact on the ecosystem:

• Identified impacts on indexers, explorers, SDKs, and APIs resulting from ledger and node changes
• Transaction construction and memory-pool sharding effects on DApps and wallets
• Physical layer visibility considerations for sophisticated use cases
• High throughput implications for event filtering efficiency
• Transaction journey time considerations from memory pool to Praos block reference.

DeltaQ analysis​

• Successfully matched ΔQ model for IB diffusion across both simulations and implementations
• Identified key differences in simulation approaches:
  • Haskell simulation includes bandwidth effects (328ms network delay per hop at 1MB/s)
  • Rust simulation currently excludes bandwidth effects
• Enabled cross-simulation topology sharing for consistent testing.