To reliably acquire attribute information on a file without abandoning a packet for transmitting the attribute information on the file in a reception terminal when packetizing the file and transmitting the packet via a unidirectional transmission path.

The transmission terminal 1 transmits attribute information necessary for recovering a file in a reception terminal 2 as a full header packet. A transmission control unit 18 transmits the full header packet of the attribute information and a compressed header packet of a plurality of units every block in this order, transmits the compressed header packet of the plurality of units in a final block, and transmits a CID record deleted packet. When the reception terminal 2 receives the full header packet of the attribute information, it generates a new CID record, generates an IP packet of the attribute information from the full header packet of the attribute information, and acquires the attribute information. A file is recovered by using the attribute information.

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