2.3.2 Core Technologies

1. Socket.io

• Simplifies the management of persistent connections, channel/room logic, and event-based messages.

• Reliable fallback from WebSockets to other protocols if necessary.

2. WebRTC

• Enables low-latency voice/video chat between users.

• Relies on a signaling process (typically via Socket.io) for NAT traversal, ICE candidate exchange, and session initiation.

3. Redis (Optional Enhancement)

• Pub/Sub: Coordinates state or message broadcasting across multiple Node.js instances (horizontal scaling).

• Caching: Stores ephemeral chat data or presence info.

4. Load Balancer (AWS ALB or NGINX)

• Distributes incoming WebSocket connections across multiple Socket.io instances, typically requiring sticky sessions or a Redis adapter so all instances can share connection state.