How do WhatsApp calls work - briefly?
WhatsApp calls are facilitated by the Voice over Internet Protocol (VoIP) technology, which transmits audio signals through the internet rather than traditional phone networks. This process ensures high-quality communication and reduces costs for users.
How do WhatsApp calls work - in detail?
WhatsApp calls, introduced in 2015, have revolutionized communication by enabling users to make voice and video calls over the internet. The process behind these calls is complex yet elegant, involving several key components and technologies.
At the core of WhatsApp calls is the Voice over Internet Protocol (VoIP), which allows voice and video data to be transmitted over the internet rather than traditional telephone networks. This technology converts analog audio signals into digital data packets that can travel through the internet more efficiently.
The call setup process begins when a user initiates a call. WhatsApp uses its proprietary signaling protocol to establish a peer-to-peer connection between the caller and the recipient. This protocol ensures secure and efficient communication, bypassing traditional telecommunication infrastructure. The signaling process involves several steps:
- Session Initiation: When a user starts a call, WhatsApp sends a session initiation request to the recipient's device. This request includes metadata such as the caller's identity and the type of call (voice or video).
- ICE Candidate Exchange: Interactive Connectivity Establishment (ICE) is used to find the best path for the media stream between the devices. Each device exchanges ICE candidates, which are potential paths for the media stream. This helps in selecting the most efficient route for the call.
- Offer/Answer Exchange: Once the best path is determined, an offer containing codec and other parameters is sent from the caller to the recipient. The recipient then responds with an answer, agreeing to the offered parameters or proposing alternatives. This negotiation ensures both devices are using compatible settings for the call.
- Media Stream Establishment: After the offer/answer exchange, the media stream is established, and the call can commence. WhatsApp uses Opus codec for audio and VP8 codec for video, ensuring high-quality communication with low latency.
During the call, WhatsApp employs end-to-end encryption to protect the user's privacy. This means that only the communicating devices can decrypt and access the media stream. WhatsApp uses the Signal Protocol developed by Open Whisper Systems for this purpose, ensuring that even WhatsApp itself cannot intercept or listen to the calls.
In addition to the technical aspects, WhatsApp calls also benefit from the platform's vast user base and integration with other features. Users can seamlessly switch between messaging and calling without leaving the app, enhancing convenience and user experience.
In conclusion, WhatsApp calls work through a sophisticated combination of VoIP technology, secure signaling protocols, and end-to-end encryption. This ensures high-quality, private communication for users worldwide, transforming how we connect with each other.