A transfer delay compensation system comprising: - a source node comprising a first forwarding physical layer, PHY, unit; and - a destination node comprising a second forwarding PHY unit with a loop-back, LB, unit; - wherein the first forwarding PHY unit is configured to exchange a plurality of symbols at a network physical layer with the second forwarding PHY unit of the destination node; - wherein the first forwarding PHY unit is configured to receive the symbols looped back from the LB unit of the destination node; - wherein the second forwarding PHY unit is configured to add a delay to the symbols looped back; - wherein the delay equals to a difference between an initial transmission time indicated in the symbols based on a local clock in the source node or an absolute clock in the network and a retransmission time at which the symbols are looped back after processing the symbols at the destination node based on a local clock in the destination node or the absolute clock in the network and therefore is a combined time for a half round-trip delay in a forward direction, D1, and a delay, D2, for processing the symbols at the destination node; - wherein the first forwarding PHY unit is configured to calculate a total delay, D4, and a half round-trip delay which equals to D1 and further equals to half of the difference between D2 and D4 calculated by the source node; - wherein the first forwarding PHY unit is configured to inform the destination node of the half round-trip delay; and - wherein the source node and the destination node are configured to use the half-round-trip delay for synchronization of their clocks. - a source node comprising a first forwarding physical layer, PHY, unit; and - a destination node comprising a second forwarding PHY unit with a loop-back, LB, unit; - wherein the first forwarding PHY unit is configured to exchange a plurality of symbols at a network physical layer with the second forwarding PHY unit of the destination node; - wherein the first forwarding PHY unit is configured to receive the symbols looped back from the LB unit of the destination node; - wherein the second forwarding PHY unit is configured to add a delay to the symbols looped back; - wherein the delay equals to a difference between an initial transmission time indicated in the symbols based on a local clock in the source node or an absolute clock in the network and a retransmission time at which the symbols are looped back after processing the symbols at the destination node based on a local clock in the destination node or the absolute clock in the network and therefore is a combined time for a half round-trip delay in a forward direction, D1, and a delay, D2, for processing the symbols at the destination node; - wherein the first forwarding PHY unit is configured to calculate a total delay, D4, and a half round-trip delay which equals to D1 and further equals to half of the difference between D2 and D4 calculated by the source node; - wherein the first forwarding PHY unit is configured to inform the destination node of the half round-trip delay; and - wherein the source node and the destination node are configured to use the half-round-trip delay for synchronization of their clocks.