Dual-Layer Architecture
The Subject Interface uses a dual-layer architecture that separates management operations from data streaming through specialized nodes.
Overview
The two components work together to provide a complete C-ITS communication solution:
API Node
The API Node implements the JSON-REST interface, providing lifecycle management and administrative control through web service endpoints.
Core Characteristics
| Characteristic |
Description |
| Protocol |
JSON-REST principles |
| Access Control |
Role-based permissions |
| Management |
Resource lifecycle operations |
| Multi-tenancy |
Cross-domain and jurisdiction support |
Responsibilities and Functions
| Function |
Purpose |
Operations |
| Session Lifecycle |
Manage streaming sessions |
Session creation with protocol selection, real-time monitoring, dynamic updates, graceful termination |
| Resource Management |
Handle CRUD operations |
Subject registrations, authorizations, tokens, accounts |
| Authentication & Authorization |
Secure access control |
Token validation, role-based access, scope restrictions, token relationships |
| Administrative Monitoring |
System visibility and logs |
Historical session data, connection logs, system health status, diagnostic information |
| Configuration Management |
System parameters |
Domain configuration, operational parameters, security settings, system limits |
Interface Categories
| Category |
Purpose |
Capabilities |
| ADMIN Interfaces |
Administrative control |
TLC registrations, authorization management, token generation/revocation, system configuration |
| SYSTEM Interfaces |
Operational functionality |
Session creation/management, streaming control, real-time data exchange, connection monitoring |
| Cross-Role Functionality |
Shared capabilities |
Dynamic subject discovery, load balancing, service distribution, domain-wide queries |
Access Control Implementation
| Component |
Implementation |
Details |
| Role-Based Validation |
Permission enforcement |
Verify roles, enforce boundaries, validate contexts, apply restrictions |
| Scope Enforcement |
Multi-level access |
Platform (full system), Domain (domain-wide), Account (owned resources), Authorization (specific TLCs) |
| Token Management |
Credential control |
Multiple active tokens, rotation without disruption, usage tracking, immediate revocation |
TCP Streaming Node
The TCP Streaming Node implements the TCP streaming protocol, managing data exchange connections and providing low latency, high-volume communication.
Core Characteristics
| Characteristic |
Description |
| Implementation |
Native TCP streaming with binary protocol |
| Data Exchange |
Continuous asynchronous bidirectional streaming |
| Payload Design |
Message-agnostic, supports any payload type |
| Monitoring |
Built-in time synchronization and health tracking |
| Feature |
Description |
| Resilience |
Automatic recovery, fault tolerance, connection state persistence |
| Horizontal Scalability |
Load balancing, stateless nodes, dynamic capacity adjustment |
| Low Latency |
Real-time communication, minimal protocol overhead, direct TCP sockets |
| High Throughput |
High-frequency messages, concurrent streams, backpressure handling |
| Resource Optimization |
Memory utilization, bandwidth management, CPU optimization, connection pooling |
Protocol and Operational Features
| Feature |
Implementation |
| Version Management |
Protocol negotiation at connect, future compatibility, graceful mismatch handling |
| Frame-Based Communication |
Structured datagrams with integrity checking, fixed headers, variable payloads |
| Time Synchronization |
Clock difference detection, regular timestamp exchanges, drift termination |
| Security Integration |
Optional TLS v1.2, per-session configuration, token-based authentication |
Core Responsibilities
| Function |
Purpose |
Operations |
| Connection Management |
TCP connection handling |
Establishment procedures, keep-alive mechanisms, health monitoring, graceful termination |
| Data Routing |
Payload distribution |
TLC to Broker routing, Broker to TLC distribution, Monitor replication, scope-based filtering |
| Time Synchronization |
Timing enforcement |
Timestamp exchanges, clock difference calculations, drift detection, automatic enforcement |
| Security Enforcement |
Policy application |
Token validation, session authentication, TLS encryption, access control verification |
| Quality Monitoring |
Performance tracking |
Latency measurements, throughput statistics, error rate tracking, performance indicators |
| Load Management |
Resource distribution |
Connection algorithms, utilization monitoring, automatic redistribution, capacity thresholds |