WhatsApp References and backup

Putting everything together

So far, we have discussed each feature, including user connection with a server, sending messages and media files, group messages, and end-to-end encryption, individually. Let’s combine these features in a single illustration and summarise our design.

• Each user is connected via Load Balancers with a WebSocket handler provided by the WebSocket server. The mapping between the WebSocket handler and a user is stored in the WebSocket Manager resides on top of the Redis cluster. A connection between users is established through WebSocket Manager. However, to reduce latency, WebSocket servers cache information stored in the WebSocket Manager, reducing traffic towards WebSocket Manager.

• After a connection is established, users can send and receive messages via Message Service. If a user is offline, the messages are stored on the Mnesia cluster ...