Embodiments of this application provide a communication method, a communication apparatus, and a communication system. A proxy client of a terminal device receives application data traffic from an application client of the terminal device; the proxy client determines first data traffic and second data traffic based on the application data traffic, and the first data traffic, the second data traffic, and the application data traffic include same data; and the proxy client sends the first data traffic to a proxy server by using a first session, and sends the second data traffic to the proxy server by using a second session, where the first session and the second session are redundant sessions for each other. In this solution, the proxy client and the proxy server implement redundant transmission of the application data traffic, to ensure correctness and reliability of data transmission, and help improve user experience.