A method for effectively implementing real time multimedia data transmission in an Ethernet network that operates in a CSMA/CD (Carrier Sense Multiple Access/Collision Detect) scheme. Real time data gets priority over general data, and uses an MPCP (Multi-Point Control Protocol) of the IEEE 802.3ah EPON to prevent a collision from occurring in real time data transmission, and also prevents delay time variation. An RT-IFG (Real Time Inter-Frame Gap) is defined for real time data, shorter than an IFG, to give priority to the real time data over general Ethernet data. The MPCP is used for transmission of real time data without collision between the real time data.