Embodiments of the disclosure provide methods, apparatus and machine-readable media relating to transport of data flows over cellular network. One method in a core network node comprises: obtaining configuration information for a data stream in an external data network, the configuration information indicating respective values for one or more fields within a header of data packets associated with the data stream which are to remain static; initiating transmission of the configuration information to a wireless device which is to receive the data stream; receiving a data packet associated with the data stream from the external data network; removing the one or more fields from the data packet to generate a compressed data packet; and initiating transmission of the compressed data packet to the wireless device.