Software-Engineering

WebRTC (Web Real-Time Communication)

What is WebRTC?

WebRTC is an open-source project that provides web browsers and mobile applications with real-time communication (RTC) capabilities via simple application programming interfaces (APIs). It allows audio and video communication to work inside web pages by allowing direct peer-to-peer communication, eliminating the need to install plugins or download native apps.

How it Works

WebRTC enables peer-to-peer communication, but it still needs servers to establish the connection.

1. Signaling: Clients exchange metadata (session control messages) to coordinate communication. This is not part of the WebRTC standard and can be done via WebSockets, HTTP, etc.
2. ICE Candidates: Interactive Connectivity Establishment (ICE) is used to find the best path to connect peers.
3. STUN/TURN Servers:
   • STUN: Tells a client what its public IP address is (traversing NAT).
   • TURN: Relays traffic if a direct peer-to-peer connection fails (e.g., strict firewalls).
4. Peer-to-Peer Connection: Once established, media and data flow directly between browsers (DTLS/SRTP).

Why We Need It & When to Use

WebRTC is the standard for browser-based real-time media.

Use WebRTC when:

• Video/Audio Conferencing: Zoom-like apps, Google Meet.
• Live Streaming: Low-latency broadcasting.
• P2P File Sharing: Sending large files directly between users without server storage.

Pros and Cons

Pros	Cons
Low Latency: Direct peer-to-peer connection minimizes delay, ideal for real-time interaction.	Complexity: Setting up the infrastructure (Signaling, STUN, TURN) is complex.
Bandwidth Efficiency: Reduces server load as media flows directly between users (except when using TURN).	UDP Reliability: Uses UDP, so packet loss can occur (video glitches), though it handles congestion well.
Security: Encryption (DTLS/SRTP) is mandatory and built-in.	Scalability: Mesh networking (connecting everyone to everyone) doesn’t scale well for large groups; requires SFU/MCU servers.
No Plugins: Native support in all modern browsers without external software.	Network Traversal: Corporate firewalls and NATs can block connections, requiring fallback to expensive TURN servers.