Method for determining a correctness of an actually received timestamp provided by a first Electronic Control Unit, ECU, of a communication network using a validator, - wherein the communication network comprises: - a master clock, the first ECU having a first slave clock, the validator having a second slave clock, and a first communication bus connecting the first ECU, the validator and the master clock to each other, - a second ECU (4, 5) having a third slave clock (41, 51), a gateway ECU comprising the validator, and a second communication bus connecting the second ECU (4, 5) via the gateway ECU and the first communication bus to the first ECU, - wherein the first ECU uses a first communication standard having a deterministic scheme, - wherein the second ECU (4, 5) uses a second communication standard having a higher safety integrity level than the first communication standard used by the first ECU, - wherein an integrity of the master clock according to the validator is sufficient to fulfill safety requirements of the second communication standard having the higher safety integrity level than the first communication standard, - the method for determining the correctness of the actually received timestamp at the validator, provided by the first ECU of the communication network comprises: - synchronizing, at the first ECU, a time of the first slave clock to a global time of the master clock, - synchronizing, at the validator, a time of the second slave clock to the global time of the master clock, - predicting, at the validator, a timestamp to be received in an actual communication cycle from the first ECU based on the deterministic scheme of the communication standard used by the first ECU, and - comparing, at the validator, the predicted timestamp with the actually received timestamp from the first ECU, - wherein the validator determines the correctness of the actually received timestamp provided by the first ECU according to the safety requirements of the second communication standard. - wherein the communication network comprises: - a master clock, the first ECU having a first slave clock, the validator having a second slave clock, and a first communication bus connecting the first ECU, the validator and the master clock to each other, - a second ECU (4, 5) having a third slave clock (41, 51), a gateway ECU comprising the validator, and a second communication bus connecting the second ECU (4, 5) via the gateway ECU and the first communication bus to the first ECU, - wherein the first ECU uses a first communication standard having a deterministic scheme, - wherein the second ECU (4, 5) uses a second communication standard having a higher safety integrity level than the first communication standard used by the first ECU, - wherein an integrity of the master clock according to the validator is sufficient to fulfill safety requirements of the second communication standard having the higher safety integrity level than the first communication standard, - a master clock, the first ECU having a first slave clock, the validator having a second slave clock, and a first communication bus connecting the first ECU, the validator and the master clock to each other, - a second ECU (4, 5) having a third slave clock (41, 51), a gateway ECU comprising the validator, and a second communication bus connecting the second ECU (4, 5) via the gateway ECU and the first communication bus to the first ECU, - wherein the first ECU uses a first communication standard having a deterministic scheme, - wherein the second ECU (4, 5) uses a second communication standard having a higher safety integrity level than the first communication standard used by the first ECU, - wherein an integrity of the master clock according to the validator is sufficient to fulfill safety requirements of the second communication standard having the higher safety integrity level than the first communication standard, - the method for determining the correctness of the actually received timestamp at the validator, provided by the first ECU of the communication network comprises: - synchronizing, at the first ECU, a time of the first slave clock to a global time of the master clock, - synchronizing, at the validator, a time of the second slave clock to the global time of the master clock, - predicting, at the validator, a timestamp to be received in an actual communication cycle from the first ECU based on the deterministic scheme of the communication standard used by the first ECU, and - comparing, at the validator, the predicted timestamp with the actually received timestamp from the first ECU, - wherein the validator determines the correctness of the actually received timestamp provided by the first ECU according to the safety requirements of the second communication standard. - synchronizing, at the first ECU, a time of the first slave clock to a global time of the master clock, - synchronizing, at the validator, a time of the second slave clock to the global time of the master clock, - predicting, at the validator, a timestamp to be received in an actual communication cycle from the first ECU based on the deterministic scheme of the communication standard used by the first ECU, and - comparing, at the validator, the predicted timestamp with the actually received timestamp from the first ECU, - wherein the validator determines the correctness of the actually received timestamp provided by the first ECU according to the safety requirements of the second communication standard.