Weekly Update 2025-04-14 (#306)

* site: weekly update

Author: will-break-it

site/news/2025-04-14-weekly-progress-summary.md

@@ -0,0 +1,65 @@
+---
+title: Weekly Summary – April 14, 2025
+authors:
+- will
+tags: [progress, update, weekly]
+---
+
+This week, the team achieved significant milestones in both the Haskell and Rust simulations, improved cost estimates, and conducted comprehensive analyses of transaction lifecycle and Full Leios simulations.
+
+### Simulation improvements
+
+#### Haskell simulation
+- Completed first draft of new mini protocols for leios diffusion
+  - Protocols modeled after BlockFetch and node-to-node Tx-Submission from ouroboros-network
+  - IB-relay, EB-relay, Vote-relay for header diffusion and body announcements
+  - IB-fetch, EB-fetch for body diffusion
+  - CatchUp protocol for older blocks
+  - See `simulation/docs/network-spec` for complete protocol details
+- Renamed `short-leios` command to `leios` since it now covers full variant as well
+  - `short-leios` is kept as alias for compatibility
+
+#### Rust simulation
+- Fixed conformance with shared trace format
+- Fixed bug with voting logic which was preventing EBs from receiving enough votes to get on-chain
+- Updated visualization to use smaller trace files to prepare for hosting on docs site
+
+### Revisions to cost dashboard
+
+The [cost dashboard](https://leios.cardano-scaling.org/cost-estimator/) was updated with lower and more realistic IO estimates.
+
+### Analysis of transaction lifecycle
+
+The Jupyter notebook [Analysis of transaction lifecycle](https://github.com/input-output-hk/ouroboros-leios/blob/leios-2025w17/analysis/tx-to-block.ipynb) estimates the delay imposed by each of the seven stages of Full Leios as a transaction moves from memory pool to being referenced by a Praos block.
+
+Key findings from the analysis:
+1. There seems little advantage to moving to stage lengths less than 10 slots
+2. The number of shards should be kept small enough so that the IB rate per shard is high relative to the stage length
+3. Low EB rates result in many orphaned IBs
+4. Realistic parameter settings result in an approximately two-minute delay between transaction submission and its referencing by an RB
+
+Potential next steps:
+- Translating this model into Delta QSD to include network effects
+- Comparing this model's results to output of the Rust simulator
+- Elaborating the model to represent the memory-pool and ledger variants under consideration
+
+### Simulation and analysis of Full Leios
+
+The team conducted comprehensive simulations using both Haskell and Rust simulators at tag [leios-2025w16](https://github.com/input-output-hk/ouroboros-leios/releases/tag/leios-2025w16). The simulations covered 648 scenarios of Full and Short Leios with varied parameters:
+- IB production rate
+- IB size
+- EB production rate
+- Stage length
+- CPU constraints
+
+Two new output files were generated:
+1. Summary of network, disk, and CPU resource usage over the course of the simulation
+2. Vertices and edges of the "Leios graph" showing linkages between transactions, IBs, EBs, RBs, and votes (can be visualized as an interactive web page)
+
+Key findings:
+- Agreement between Rust and Haskell simulations is generally quite close
+- The Haskell simulation experiences network congestion at 16 IB/s, but the Rust simulation does not
+- The Rust simulation uses more CPU at high IB rates than the Haskell simulation
+- The Rust simulation sometimes does not produce enough votes to certify an EB
+
+Detailed results are available in the Jupyter notebook [analysis/sims/2025w16/analysis.ipynb](https://github.com/input-output-hk/ouroboros-leios/blob/leios-2025w17/analysis/sims/2025w16/analysis.ipynb).