Patent ID: 8472479

Claim:
A data transmission method for continuously transmitting data in packet units to a receiving end, each packet unit containing transmission data, the data transmission method comprising: receiving transmission data that is a target of a transmission of a sender; transmitting an uncompressed packet in which predetermined transmission data is stored as uncompressed data, the predetermined transmission data being included in the transmission data received by said receiving of the transmission data and the predetermined transmission data being the target of the transmission of the sender; setting an initial value of reference data to the predetermined transmission data included in the transmission data received by said receiving of the transmission data; forming compressed data that is to be stored in any packet other than the uncompressed packet, the compressed data being formed based on the reference data and transmission data to be compressed; subsequently and continuously transmitting compressed packets in which at least a portion of the transmission data to be compressed is compressed and stored as the compressed data; and updating the reference data to be the transmission data that is the target of the transmission of the sender and that is uncompressed, the reference data being updated when a transmitted compressed packet, of the transmitted compressed packets, includes an update flag and the update flag indicates that the reference data is to be updated.