A network node for packet data processing, the network node comprising a time-transfer protocol processing unit adapted to generate negotiation messages and management messages for a time-transfer protocol and to forward said negotiation and management messages to one or more remote network nodes, and a network processor unit consisting of separate hardware resources from the time-transfer protocol processing unit and adapted to: perform routing operations, or switching operations, or both, on first data packets received from one or more line ports and transmitted on one or more backplane ports and second data packets received from the one or more backplane ports and transmitted on the one or more line ports, wherein the first and second data packets do not include time-transfer protocol timestamp data; receive a configuration message from the time-transfer protocol processing unit, the configuration message comprising stream configuration data for a first type of repetitive time-transfer message; generate a plurality of repetitive time-transfer messages according to the first type of repetitive time-transfer message, using the stream configuration data; and forward said plurality of repetitive time-transfer messages to the one or more remote network nodes, via the one or more line ports. a time-transfer protocol processing unit adapted to generate negotiation messages and management messages for a time-transfer protocol and to forward said negotiation and management messages to one or more remote network nodes, and a network processor unit consisting of separate hardware resources from the time-transfer protocol processing unit and adapted to: perform routing operations, or switching operations, or both, on first data packets received from one or more line ports and transmitted on one or more backplane ports and second data packets received from the one or more backplane ports and transmitted on the one or more line ports, wherein the first and second data packets do not include time-transfer protocol timestamp data; receive a configuration message from the time-transfer protocol processing unit, the configuration message comprising stream configuration data for a first type of repetitive time-transfer message; generate a plurality of repetitive time-transfer messages according to the first type of repetitive time-transfer message, using the stream configuration data; and forward said plurality of repetitive time-transfer messages to the one or more remote network nodes, via the one or more line ports. perform routing operations, or switching operations, or both, on first data packets received from one or more line ports and transmitted on one or more backplane ports and second data packets received from the one or more backplane ports and transmitted on the one or more line ports, wherein the first and second data packets do not include time-transfer protocol timestamp data; receive a configuration message from the time-transfer protocol processing unit, the configuration message comprising stream configuration data for a first type of repetitive time-transfer message; generate a plurality of repetitive time-transfer messages according to the first type of repetitive time-transfer message, using the stream configuration data; and forward said plurality of repetitive time-transfer messages to the one or more remote network nodes, via the one or more line ports.