Communication network and method of controlling the communication network

1. A communication network with at least two network nodes, with at least one transmission channel for transmitting data packets between the network nodes, and with at least one active coupler, wherein coupler information is attached to the data packets as they pass through the active coupler, and data-packet running-time information is determined from the coupler information in a network node that receives a data packet, and the network node uses the data-packet running-time information to facilitate synchronization between clocks of the network nodes.

2. A communication network as claimed in claim 1 , characterized in that an item of counting information relating to the number of active couplers passed through is added to the data packets as coupler information.

3. A communication network as claimed in claim 1 , characterized in that identification information, which unambiguously identifies a particular active coupler passed through, is added to the data packets as coupler information.

4. A communication network as claimed in claim 1 , characterized in that the network nodes are equipped with a memory in which an associated running-time delay is stored for a particular number of active coupler passed through.

5. A communication network as claimed in claim 1 , characterized in that the network nodes are each equipped with a monitoring circuit for detection of the drop-out of transmission paths, wherein, if the running time of a received data packet differs from the running time normal hitherto, the monitoring circuit detects the drop-out of a transmission path.

6. A communication network as claimed in claim 1 , characterized in that at least one star coupler is provided as the active coupler with at least three star interfaces, that the star interfaces of the star coupler are each provided in order to route a data packet, as a function of an activation signal, from the assigned network node to the other star interfaces or from one of the other star interfaces to at least one of the assigned network nodes.

7. A communication network as claimed in claim 1 , characterized in that the data packets are equipped with an identification section, in particular a preamble, and that the active couplers are equipped to add the coupler information to the data packets by changing the identification section.

8. A communication network as claimed in claim 7 , characterized in that the identification section is equipped with an equisignal, in particular a d.c. voltage signal, and that the active couplers are each provided in order to add the coupler information by changing the length of the equisignal.

9. A communication network as claimed in claim 7 , characterized in that the identification section is equipped with a number of pulses and that the active couplers are provided in order to add the coupler information by changing the number of pulses.

10. A vehicle with a communication network as claimed in claim 1 .

11. A communication network comprising: at least two network nodes, at least one transmission channel for transmitting data packets between the network nodes, and at least one active coupler that attaches coupler information to the data packets as they pass through the active coupler, wherein data-packet running-time information is determined from the coupler information in a network node that receives a data packet, characterized in that a communication time schedule is provided, which assigns to the individual network nodes time slots for the transmission of the data packets, that the network nodes are each equipped with at least one communication controller with a local time scheduler for controlling the access of the network nodes to the transmission channels in accordance with the communication time schedule, and that the running-time information for the data packets determined in the receiving nodes is used to improve the synchronization of the local time schedulers.

12. A communication network as claimed in claim 11 , further comprising a plurality of active couplers, wherein the coupler information attached to the data packets as they pass though a particular one of the active couplers unambiguously identifies the particular one of the active coupler passed though.

13. A communication network as claimed in claim 11 , further comprising a plurality of active couplers, wherein the network nodes are each equipped with a memory in which an associated running-time delay is stored for each of the active couplers.

14. A communication network as claimed in claim 11 , wherein the data packets are each equipped with a preamble, and the active coupler is equipped to add the coupler information to the data packets by changing the preambles.

15. A communication network as claimed in claim 11 , wherein the network nodes are each equipped with a monitoring circuit for detecting drop-out of transmission paths in the communication network, the monitoring circuit detecting the drop-out of a transmission path responsive to data-packet running-time information of a received data packet.

16. A method of controlling a communication network with at least two network nodes, with at least one active coupler and with at least one transmission channel for transmitting data packets between the network nodes, the method comprising: attaching coupler information to the data packets as they pass through the active coupler, determining data-packet running-time information from the coupler information in a network node that receives a data packet, and using the data-packet running-time information to facilitate synchronization between clocks of the network nodes.

17. An active coupler for a network with at least two network nodes, wherein the active coupler is provided in order to attach to data packets as they pass through the active coupler, coupler information that enables data-packet running-time information to be determined in a network node that receives a data packet and that enables the network node that receives the data packet to facilitate synchronization between clocks of the network nodes responsive to the determined data-packet running-time information.

18. A network node for a communication network, wherein the network node is provided in order to determine, on receipt of a data packet, data-packet running-time information from coupler information attached to the data packet as it passes through an active coupler and to use the data-packet running-time information to facilitate synchronization between clocks of network nodes of the communication network.