Method for operating units of a communication system

A method for operating a first communication unit of a communication system in order to determine, using a second communication unit, a maximum value for a latency time of a data packet transmitted from the first communication unit to the second communication unit of the communication system, each of the first and second communication units including a respective processing system that includes at least one processor and including a respective communication interface via which communication between the first and second communication units is enabled, and the second communication unit further including a clock, the method comprising:

• receiving over time, by the first communication unit, via the communication interface of the first communication unit, from the second communication unit, and without data packet transmissions from the first communication unit to the second communication unit, a plurality of token messages that each includes respective time information representing a respective reference time of the respective token message generated by the second communication unit based on a respective clock value of the clock that is extant when the respective token message is generated;
• and
• subsequent to the receipt of the plurality of token messages, transmitting, by processing system of the first communication unit and using the communication interface of the first communication unit, the data packet with the respective time information included in one of the plurality of token messages to the second communication unit in order to determine, using the second communication unit, the maximum value for the latency time of the data packet transmitted from the first communication unit to the second communication unit, based on the time information included in the data packet, wherein the time information included in the data packet is:
• whichever of the time information that had been included in a last one of the token messages that the first communication unit had received from the second communication unit;
• or
• whichever of the time information that represents a most recent one of the reference times.

A method for operating a second communication unit of a communication system in order to determine, by the second communication unit, a maximum value for a latency time of a data packet transmitted from a first communication unit of the communication system to the second communication unit, each of the first and second communication units including a respective processing system that includes at least one processor and including a respective communication interface via which communication between the first and second communication units is enabled, and the second communication unit further including a clock, the method comprising the following steps:

• sending, to the first communication unit and by the processing system of the second communication unit using the communication interface of the second communication unit, at least one token message including time information representing a reference time of the token message, which is based on the clock of the second communication unit, wherein the first communication unit, to which the second communication unit sends the at least one token message, is configured to locally record the reference time represented by the time information included in the at least one token message;
• receiving, by the second communication unit and from the first communication unit, a data packet that is transmitted by the first communication unit to the second communication unit after a delay since receipt by the first communication unit of the at least one token message and upon the first communication unit reaching, independently of the receipt of the at least one token message, a state in which the first communication unit has data to be transmitted to the second communication unit, wherein the data packet includes the data and further includes an identification of the reference time that the first communication unit had locally stored;
• and
• determining, by the processing system of the second communication unit, the maximum value for the latency time of the data packet transmitted from the first communication unit to the second communication unit, based on the identified reference time included in the data packet.

A method for operating a communication system including a first communication unit and a second communication unit in order to determine, using the second communication unit, a maximum value of a latency time of a data packet transmitted from the first communication unit to the second communication unit, each of the first and second communication units including a respective processing system that includes at least one processor and including a respective communication interface via which communication between the first and second communication units is enabled, and the second communication unit further including a clock, the method comprising the following steps:

• sending to the first communication unit by the processing system of the second communication unit using the communication interface of the second communication unit, at least one token message including time information representing a reference time of the token message, which is based on the clock of the second communication unit;
• receiving, by the first communication unit via the communication interface of the first communication unit, the at least one token message sent from the second communication unit to the first communication unit;
• locally recording, by the processing system of the first communication unit, the reference time represented by the time information included in the at least one received token message;
• after a delay since receipt of the at least one token message and upon the first communication unit reaching, independently of the receipt of the at least one token message, a state in which the first communication unit has data to be transmitted to the second communication unit, sending, by the processing system of the first communication unit using the communication interface of the first communication unit, the data packet including the data to the second communication unit, wherein the data packet further includes an identification of the locally recorded reference time;
• receiving, by the second communication unit via the communication interface of the second communication unit, the data packet transmitted from the first communication unit to the second communication unit;
• and
• determining, by the processing system of the second communication unit, the maximum value for the latency time of the data packet transmitted from the first communication unit to the second communication unit, based on the identified reference time included in the data packet.

A first communication unit of a communication system that further includes a second communication unit, the second communication unit of the communication system including a second processing system that includes at least one processor, a second communication interface, and a clock, the first communication unit comprising:

• a first processing system that includes at least one processor;
• and
• a first communication interface;
• wherein the first processing system is configured to:
• receive, via the first communication interface, at least one token message sent by the second processing system of the second communication unit using the second communication interface to the first communication unit, the token message including time information representing a reference time of the token message, which is based on the clock of the second communication unit;
• locally record the reference time represented by the time information included in the at least one received token message;
• and
• after a delay since receipt of the at least one token message and upon the first communication unit reaching, independently of the receipt of the at least one token message, a state in which the first communication unit has data to be transmitted to the second communication unit, send, via the first communication interface, a data packet including the data to the second communication unit, wherein the data packet further includes an identification of the locally recorded reference time, in order to determine, using the second communication unit, a maximum value for a latency time of the data packet transmitted from the first communication unit to the second communication unit based on the identification of the locally recorded reference time included in the data packet.

A second communication unit of a communication system that further includes a first communication unit, the first communication unit of the communication system including a first processing system that includes at least one processor and a first communication interface, the second communication unit comprising:

• a second processing system that includes at least one processor;
• a second communication interface;
• and
• a clock;
• wherein the second processing system is configured to:
• send, using the second communication interface, at least one token message including time information representing a reference time of the token message, which is based on the clock of the second communication unit, to a first communication unit of a communication system, the communication system including the first communication unit and the second communication unit, wherein the first processing system of the first communication unit, to which the second communication unit sends the at least one token message, is configured to locally record the reference time represented by the time information included in the at least one token message;
• receive, via the second communication interface and from the first communication unit, a data packet that is transmitted by the first communication unit to the second communication unit after a delay since receipt by the first communication unit of the at least one token message and upon the first communication unit reaching, independently of the receipt of the at least one token message, a state in which the first communication unit has data to be transmitted to the second communication unit, wherein the data packet includes the data and further includes an identification of the reference time that the first communication unit had locally stored;
• and
• determine a maximum value for a latency time of the data packet transmitted from the first communication unit to the second communication unit based on the identified reference time included in the data packet.

A communication system, comprising:

• a first communication unit that includes first communication interface and a first processing system having at least one processor;
• and
• a second communication unit including a second communication interface, a clock, and a second processing system that includes at least one processor;
• wherein:
• the second processing system of the second communication unit is configured to send, using the second communication interface and to the first communication unit, at least one token message including time information representing a reference time of the token message, which is based on the clock of the second communication unit;
• the first processing system of the first communication unit is configured to:
• receive, via the first communication interface, the at least one token message sent from the second communication unit to the first communication unit;
• locally record the reference time represented by the time information included in the at least one received token message;
• and
• after a delay since receipt of the at least one token message and upon the first communication unit reaching, independently of the receipt of the at least one token message, a state in which the first communication unit has data to be transmitted to the second communication unit, transmit, using the communication interface, a data packet including the data to the second communication unit, wherein the data packet further includes an identification of the locally recorded reference time;
• and
• the second processing system of the second communication unit is configured to:
• receive, via the second communication interface, the data packet transmitted from the first communication unit to the second communication unit, and
• determine a maximum value for a latency time of the data packet transmitted from the first communication unit to the second communication unit based on the identified reference time included in the data packet.

A non-transitory machine-readable storage medium on which is stored a computer program for operating a first communication unit of a communication system in order to determine, using a second communication unit, a maximum value for a latency time of a data packet transmitted from the first communication unit to the second communication unit of the communication system, each of the first and second communication units including a respective processing system that includes at least one processor and including a respective communication interface via which communication between the first and second communication units is enabled, and the second communication unit further including a clock, the computer program, when executed by the processing system of the first communication unit, causing the processing system of the first communication unit to perform the following steps:

• receiving, by the first communication unit and via the communication interface of the first communication unit, at least one token message sent from the second communication unit to the first communication unit, the token message including time information representing a reference time of the token message, which is based on the clock of the second communication unit;
• locally recording, by the first communication unit, the reference time represented by the time information included in the at least one received token message;
• and
• after a delay since receipt of the at least one token message and upon the first communication unit reaching, independently of the receipt of the at least one token message, a state in which the first communication unit has data to be transmitted to the second communication unit, sending, by the first communication unit and using the communication interface of the first communication unit, the data packet including the data to the second communication unit, wherein the data packet further includes an identification of the locally recorded reference time, in order to determine, using the second communication unit, the maximum value for the latency time of the data packet transmitted from the first communication unit to the second communication unit, based on the identification of the locally recorded reference time included in the data packet.