Abstract: In a network node synchronization method and system a first timestamp (TSA) is captured at a first network node system (A) just prior to transmitting a data packet (DP) to a second network node system (B) and incorporated in said data packet (DP). Upon receiving a control block of data (SFD) comprised in the data packet (DP), the second network node system (B) captures a second timestamp (TSB). The delay between capturing the first timestamp (TSA) and the second timestamp (TSB) comprises a number of deterministic delays and a propagation time (PT). Eliminating the deterministic delays, only a small synchronization error due to the propagation time (PT) remains. As the propagation time (PT) may be very small, the synchronization may be very accurate. Further, as the synchronization may be performed using any data packet (DP), the present invention may be employed in any kind of network system and network protocol.