vss-wamp-notes.md

VSS-WAMP mapping variants

native mapping

Mapping convention - variant I ("native mapping")

• VISS path: "Vehicle/Drivetrain/InternalCombustionEngine/RPM"
• <VIN>: Vehicle ID

=>

• WAMP prefix: "org.w3c.automotive.viss.vehicle.<VIN>.drivetrain.internal-combustion-engine.rpm"

Procedures:

• <PREFIX>.get() -> rpm|int
• <PREFIX>.get_history(from|string, to|string) -> [rpm|int] ...

Topics:

• <PREFIX>.on_changed() -> rpm|int
• <PREFIX>.on_limiter_triggered() -> timestamp|string ...

Given above, one can then:

• WAMP regular-subscribe to: "org.w3c.automotive.viss.vehicle.<VIN>.drivetrain.internal-combustion-engine.rpm.on_changed"
• WAMP prefix-subscribe to: "org.w3c.automotive.viss.vehicle.<VIN>.drivetrain."
• WAMP wildcard-subscribe to: "org.w3c.automotive.viss.vehicle.*.drivetrain.internal-combustion-engine.rpm.on_changed"

If collective/structure signal retrieval is a goal, then one can provide eg

• WAMP prefix: "org.w3c.automotive.viss.vehicle.<VIN>.drivetrain.internal-combustion-engine"

Procedures:

• <PREFIX>.get() -> {"rpm": rpm|int, ...}
• <PREFIX>.get_history(from|string, to|string) -> [{"rpm": rpm|int, ...}] ...

---

• VISS path: "Vehicle/Drivetrain/Transmission/PerformanceMode"
• <VIN>: Vehicle ID

=>

• WAMP prefix: "org.w3c.automotive.viss.vehicle.<VIN>.transmission.performance-mode"

Procedures:

• <PREFIX>.set(performance_mode|string) -> performance_mode|string ...

Topics:

• <PREFIX>.on_changed() -> performance_mode|string ...

gen2-on-WAMP mapping

Mapping convention - variant II ("gen2-on-WAMP mapping")

"The transport protocols used to implement these methods MUST implement the Read and Update methods, and MAY implement the Subscribe, Unsubscribe, and Subscription methods."

• <VIN>: Vehicle ID

=>

• WAMP prefix: "org.w3c.automotive.viss.vehicle.<VIN>"

WAMP procedures (7.1.1 Read, 7.1.2 Update, 7.1.3 Subscribe, 7.1.4 Unsubscribe):

• <PREFIX>.get(signal_path|string) -> current_value|type
• <PREFIX>.update(signal_path|string, req_value|type) -> new_value|type
• <PREFIX>.subscribe(signal_path|string, filter, ..) -> signal_subscription|int
• <PREFIX>.unsubscribe(signal_subscription|int) -> - ...

WAMP topics (7.1.5 Subscription):

• <PREFIX>.subscriptions.<signal_subscription|int>

summary

• Vehicle Signal Specification (VSS) => np, can be mapped easily (and natively)
• gen2 core (see below), gen2 transport: unneeded (for WAMP)
• gen2 core:
  • Service Discovery => np, can use the WAMP meta API for that
  • Filtering => in this general way, only with (variant II) below. but ..
  • Access Control Model => no easy mapping - WAMP separates authentication and authorization, as well as decouples this from transport specific mechanisms. both are kinda convoluted in gen2 (core) IMO