Like HTTP, RTSP uses TCP to maintain an end-to-end connection and, while most RTSP control messages are sent by the client to the server, some commands travel in the other direction (i.e. from server to client).
像HTTP一样，RTSP使用TCP来维护端到端连接，而大多数RTSP控制消息由客户端发送到服务器，一些命令沿着另一个方向（即从服务器到客户端）传播。