A method for transmitting data in real time in a multimedia data stream over a local network is provided. The local network comprises a sending end and one or more receiving ends. The method includes the steps of packaging a QoS (quality of service) control signal into a QoS packet according to a RTCP/TCP/IP protocol; packaging the multimedia data stream into a multimedia data packet according to a RTP/UDP/IP protocol; establishing a connection between the sending end and one of the one or more receiving ends; delivering the QoS packet and the multimedia data packet from the sending end to the one or more receiving end over the local network; and the one or more receiving end de-packaging the QoS packet into the QoS signal to control the transmission of the multimedia data stream.