Method for transmitting real-time messages in a computer network , in particular real-time computer network, - wherein said computer network comprises two or more computing nodes and one or more star couplers , wherein said computing nodes are interconnected via at least one star coupler , wherein each computing node is connected to the at least one star coupler via at least one of the communication links , and wherein the computing nodes exchange messages (M1, M2) with one another and with the at least one star coupler, wherein a global time base (C) is provided, and wherein the messages comprise at least a first non-empty set (SSET) of real-time messages; and - wherein star couplers, which are synchronized to the global time base (C), transmit said first non-empty set (SSET) of real-time messages according to a synchronized communication paradigm in which real-time messages are transmitted according to a communication schedule, and - wherein computing nodes , which are synchronized to the global time base (C), transmit said first non-empty set of real-time (SSET) messages according to the synchronized communication paradigm, characterised in that the at least one star coupler , which has lost synchronization to the global time base (C), and a computing node of the two or more computing nodes, which has lost synchronization to the global time base (C), - transmits a second non-empty subset (CSET) of said first non-empty subset (SSET) of real-time messages according to an unsynchronized communication paradigm and stops the transmission of said second non-empty subset (CSET) of real-time messages according to the synchronized communication paradigm, wherein said second non-empty subset (CSET) comprises real-time messages defined as critical. - wherein said computer network comprises two or more computing nodes and one or more star couplers , wherein said computing nodes are interconnected via at least one star coupler , wherein each computing node is connected to the at least one star coupler via at least one of the communication links , and wherein the computing nodes exchange messages (M1, M2) with one another and with the at least one star coupler, wherein a global time base (C) is provided, and wherein the messages comprise at least a first non-empty set (SSET) of real-time messages; and - wherein star couplers, which are synchronized to the global time base (C), transmit said first non-empty set (SSET) of real-time messages according to a synchronized communication paradigm in which real-time messages are transmitted according to a communication schedule, and - wherein computing nodes , which are synchronized to the global time base (C), transmit said first non-empty set of real-time (SSET) messages according to the synchronized communication paradigm, characterised in that the at least one star coupler , which has lost synchronization to the global time base (C), and a computing node of the two or more computing nodes, which has lost synchronization to the global time base (C), - transmits a second non-empty subset (CSET) of said first non-empty subset (SSET) of real-time messages according to an unsynchronized communication paradigm and stops the transmission of said second non-empty subset (CSET) of real-time messages according to the synchronized communication paradigm, wherein said second non-empty subset (CSET) comprises real-time messages defined as critical. <EOS>