Coordinates

Coordinates use the Vivaldi algorithm to estimate P2P latency, creating a scalable “map” of network topology in virtual space.

1. Purpose

• Estimate RTT between naras without full-mesh pinging.
• Drive proximity-based social behaviors and “best friends.”
• Optimize World Postcard routing.
• Network visualization in the web UI.

2. Conceptual Model

• Virtual Space: 2D Euclidean plane where naras “move” based on latency.
• Height: A third dimension for “last-mile” (non-Euclidean) latency.
• Confidence: Error score (0.0 to 1.0) indicating coordinate accuracy.

Invariants

• Refinement: Coordinates stabilize over time as real pings are observed.
• Prediction: Estimated_RTT = Euclidean_Distance(A, B) + A.Height + B.Height.

3. External Behavior

• Automatic Updates: Triggered by Mesh HTTP /ping or PingObservation events.
• Influence Bonus: 30% boost to opinions for nearby naras.
• Barrios: Latency clustering into neighborhoods (see Aura & Avatar).

4. Interfaces

NetworkCoordinate Structure

• x, y, height, error.

HTTP API

• GET /coordinates: Returns local virtual position.

5. Algorithms

Vivaldi Update

Triggered when measuring RTT r to peer:

1. Weight: w = me.Error / (me.Error + peer.Error).
2. Relative Error: e_rel = |Predicted_RTT - r| / r.
3. Error Update: me.Error = (e_rel * Cc * w) + (me.Error * (1 - Cc * w)).
4. Position: Move me.pos along the unit vector from peer to me based on (r - Predicted_RTT).
5. Height: Adjust me.Height by displacement factor.

Proximity Bonus

Bonus = 100 / max(1, Measured_Distance_in_ms).

6. Failure Modes

• Oscillation: Unstable networks may prevent convergence.
• Triangle Inequality Violation: High-latency direct links “bend” virtual space.
• Spoofing: Coordinates are self-reported and not cryptographically verified.

7. Test Oracle

• TestVivaldi_UpdateConvergence: Stability checks.
• TestVivaldi_DistanceCalculation: Euclidean + height verification.
• TestProximity_Influence: Clout boost validation.