An apparatus for use in a SpaceWire-based network is configured to send and receive data packets, and process data included in a received data packet. A header of the received data packet is stored in a buffer while the data is being processed, a processed data packet including the stored header and the processed data is generated, and the processed data packet is transmitted. The header of the received data packet may be modified, and the modified header attached to the processed data to generate the processed data packet. When the data packet is received via a first port, the processed data packet may be transmitted via the first port, or may be transmitted via a second port.