Method for synchronizing control applications via a communication network for transferring time-critical data, in which - the communication network comprises communication terminals (201-203) at starting and end nodes of paths for data streams and network infrastructure devices (101-110) at intermediate nodes, selected data streams being associated with control applications running on communication terminals , - the network infrastructure devices ascertain a particular time delay (L(i)) between a scheduled time of transmission (TX P (i)) for a datagram and its actual time of transmission (TX(i)) when forwarding datagrams (11-12) associated with the selected data streams, - the network infrastructure devices send particular information about the ascertained time delay to a network infrastructure device or communication terminal that is subsequent along the respective path, - the network infrastructure devices compute the scheduled time of transmission (TX P (i)) on the basis of a particular time of reception (RX(i)) of the datagrams and a time delay (L(i-1)) ascertained by a communication terminal or network infrastructure device that is precedent along the respective path, - an accumulated maximum time delay (D MAX ) between starting nodes and end nodes is ascertained for a transmission of the selected data streams, - synchronization between transmission cycles of starting-node control applications and transmission cycles of end-node control applications is achieved by virtue of the starting-node control application taking the time delay ascertained by the precedent network infrastructure device, the accumulated maximum time delay and a time of transmission (TX APP ) of the datagrams as a basis for ascertaining a particular start (T SYNC ) of a next end-node transmission cycle. - the communication network comprises communication terminals (201-203) at starting and end nodes of paths for data streams and network infrastructure devices (101-110) at intermediate nodes, selected data streams being associated with control applications running on communication terminals , - the network infrastructure devices ascertain a particular time delay (L(i)) between a scheduled time of transmission (TX P (i)) for a datagram and its actual time of transmission (TX(i)) when forwarding datagrams (11-12) associated with the selected data streams, - the network infrastructure devices send particular information about the ascertained time delay to a network infrastructure device or communication terminal that is subsequent along the respective path, - the network infrastructure devices compute the scheduled time of transmission (TX P (i)) on the basis of a particular time of reception (RX(i)) of the datagrams and a time delay (L(i-1)) ascertained by a communication terminal or network infrastructure device that is precedent along the respective path, - an accumulated maximum time delay (D MAX ) between starting nodes and end nodes is ascertained for a transmission of the selected data streams, - synchronization between transmission cycles of starting-node control applications and transmission cycles of end-node control applications is achieved by virtue of the starting-node control application taking the time delay ascertained by the precedent network infrastructure device, the accumulated maximum time delay and a time of transmission (TX APP ) of the datagrams as a basis for ascertaining a particular start (T SYNC ) of a next end-node transmission cycle. <EOS>