The present invention relates to a device and method for transmitting/receiving a packet in a communication system. The present invention includes: the processes of determining at least one MPEG media transport (MMT) asset protected by an application layer forward error correction (AL-FEC); determining at least one FEC flow for transmitting the at least one MMT asset; determining the MMT asset transmitted from the at least one FEC flow in each case and determining an FEC coding structure to apply to the at least one FEC flow; producing at least one source flow by dividing the MMT asset transmitted from the at least one FEC flow on a transmission unit basis; and producing and transmitting at least one parity flow by performing AL-FEC encoding on the at least one source flow according to the FEC coding structure.