Mesh Routing Fabric

Conduit uses a two-plane architecture to handle both real-time data and analytical queries.

Two Data Planes

Real-Time Plane (NATS)

NATS handles all push-based, real-time data:

• Tag subscriptions: Subscribe to uns.PlantA.Line3.Filler01.temperature and receive updates in under 1ms
• Wildcard patterns: uns.PlantA.Line3.> subscribes to everything on Line 3
• Edge-to-edge: Translators communicate directly through NATS without involving the control plane
• JetStream: Persistent streams for bulk export and replay after consumer disconnection

NATS subjects map 1:1 to UNS paths. The delimiter changes from / to .:

| UNS Path | NATS Subject | | ----------------------------------- | --------------------------------------- | | PlantA/Line3/Filler01/temperature | uns.PlantA.Line3.Filler01.temperature | | PlantA/Line3/* (wildcard) | uns.PlantA.Line3.> |

Query Plane (MCP over HTTP)

MCP handles all request-response patterns:

• NQE queries: Natural language to structured query to execution
• Tool discovery: tools/list aggregates capabilities across all translators
• Bulk history: Large result sets from Splunk, historians
• Tool calls: tools/call dispatches queries to specific translators

Message Format

All NATS messages use a compact JSON envelope:

{
  "v": 72.3,
  "ts": 1739462400000,
  "q": "good",
  "u": "degF",
  "src": "opcua-translator-01"
}

| Field | Type | Description | | ----- | ------ | --------------------------------------- | | v | any | Value (number, string, boolean, object) | | ts | number | Unix timestamp (milliseconds) | | q | string | Quality: good, uncertain, bad | | u | string | Engineering unit (optional) | | src | string | Source translator ID |

Translators

Each translator is a standalone Docker container that:

1. Connects to NATS and publishes tag values
2. Exposes an MCP server (tools/list, tools/call)
3. Auto-registers with Conduit Core on startup
4. Speaks its native protocol (SPL, MQTT, OPC-UA, Modbus, etc.)

Available Translators

| Translator | Native Protocol | Status | | --------------- | ------------------------------- | ---------- | | Splunk | REST / SPL | Production | | MQTT | mqtt.js v5 | Production | | OPC-UA | node-opcua | Production | | MCP IoT Gateway | Modbus, S7, EtherNet/IP, BACnet | Production |

Translator Lifecycle

1. Start → Load config
2. Connect to NATS
3. Connect to native data source
4. Start publishing values to NATS subjects
5. Start MCP server (HTTP)
6. Register with Conduit Core (POST /mcp → initialize)
7. Accept MCP tool calls for queries
8. On shutdown → Deregister → Disconnect

Latency

| Pattern | Latency | | ----------------------------------- | ------------------ | | Single tag subscription (same site) | 0.2-2ms | | Wildcard subscription | 0.5-1ms per update | | Edge-to-edge (same site) | 1-3ms | | Cross-site via federation | 5-25ms | | Historical query (MCP) | 200ms-30s |

Next Steps

• Federation — Multi-plant setup
• Architecture — Full system overview