A method for transmitting messages via a time-controlled communication system (ZK) between a number of IP cores is provided. Each IP core has an information-processing subsystem (IVS) and a network controller (NK). Each NK has at least two interfaces, one for the ZK and a one for the IVS, wherein a distinction is drawn between privileged and non-privileged messages of the ZK, and where the transmission parameters relating to the ZK of a port of the NK, such as the periodically recurring transmission time of a message and the maximum transmission duration after each transmission time, can be set by a privileged message via the ZK or directly by a privileged entity. Each NK intending to transmit a message starts to transmit the message autonomously exactly at the time of the next set transmission time and interrupts the transmission process no later than the assigned maximum transmission duration has elapsed.