2.5.2 Infrastructure Diagram

                         ┌───────────────────────────────────────┐
                         │          Amazon Route 53             │
                         └───────────────────────────────────────┘
                                       ↓
                         ┌───────────────────────────────────────┐
                         │   AWS CloudFront (CDN) + S3 (React)   │
                         └───────────────────────────────────────┘
                                       ↓
             ┌────────────────────────────────────────────────────────┐
             │            AWS ALB (Load Balancer)                    │
             └────────────────────────────────────────────────────────┘
                 │ (HTTPS)                        │ (HTTPS/WebSockets)
     ┌─────────────────────────┐         ┌─────────────────────────┐
     │ ECS Service (Backend)   │         │ ECS Service (Socket.io) │
     │ Node.js/Express + Auth  │         │ Real-Time + WebRTC      │
     └─────────────────────────┘         └─────────────────────────┘
                     ↓                          ↓
     ┌────────────────────────────┐    ┌──────────────────────────────┐
     │   Amazon RDS (PostgreSQL)  │    │ Amazon ElastiCache (Redis)   │
     └────────────────────────────┘    └──────────────────────────────┘

Flow:

1. DNS (Route 53) → CloudFront + S3 for static assets (React).

2. For API calls and real-time Socket.io connections, traffic goes to the Load Balancer (ALB).

3. Requests are routed to the appropriate ECS service task (backend REST or real-time instance).

4. These services communicate with RDS (PostgreSQL) for persistent data and ElastiCache (Redis) for caching and Pub/Sub.