Communication device, communication method, recording medium and program

A data transmitting methods comprising:

• transmitting a check packet to a data receiving apparatus using a User Datagram Protocol UDP;
• receiving an acknowledgment message to the check packet from the data receiving apparatus, the acknowledgment message including acknowledgment information based on shared data shared with said data receiving apparatus;
• computing an expected acknowledgement information based on the shared data shared with said data receiving apparatus;
• producing a comparison result for said data receiving apparatus based on the acknowledgment information and the expected acknowledgement information;
• determining whether a response time of the acknowledgment message is less than a predetermined time;
• and
• judging whether subsequent content data transmitted to said data receiving apparatus will be limited in usage right based on the comparison result in the producing step and the determination in the determining step, if the UDP acknowledgement message is not received, the judgment unit determines that the data receiving apparatus is connected to the data transmitting apparatus through a second network, and the subsequent data content data transmitted is limited in usage right.

A computer readable storage medium encoded with computer program instructions which cause a computer to execute a method of controlling a data transmission comprising:

• transmitting a check packet to a data receiving apparatus using a User Datagram Protocol (UDP);
• receiving a UDP acknowledgment message to the check packet from the data receiving apparatus, the acknowledgment message including acknowledgment information based on shared data shared with said data receiving apparatus;
• computing an expected acknowledgement information based on the shared data shared with said data receiving apparatus;
• producing a comparison result for said data receiving apparatus based on the acknowledgment information and the expected acknowledgement information;
• determining whether a response time of the acknowledgment message is less than a predetermined time;
• and
• judging whether subsequent content data transmitted to said data receiving apparatus will be limited in usage right based on the comparison result in the producing step and the determination in the determining step, if the UDP acknowledgement message is not received, the judgment unit determines that the data receiving apparatus is connected to the data transmitting apparatus through a second network, and the subsequent data content data transmitted is limited in usage right.

A data transmitting apparatus comprising:

• means for transmitting a check packet to a data receiving apparatus using a User Datagram Protocol (UDP);
• means for receiving a UDP acknowledgment message to the check packet from the data receiving apparatus, the acknowledgment message including acknowledgment information based on shared data shared with said data receiving apparatus;
• means for computing an expected acknowledgement information based on the shared data shared with said data receiving apparatus;
• means for producing a comparison result for said data receiving apparatus based on the acknowledgment information and the expected acknowledgement information;
• means for determining whether a response time of the acknowledgment message is less than a predetermined time;
• and
• means for judging whether subsequent content data transmitted to said data receiving apparatus will be limited in usage right based on the comparison result and the determination of means for determining, if the UDP acknowledgement message is not received, the judgment unit determines that the data receiving apparatus is connected to the data transmitting apparatus through a second network, and the subsequent data content data transmitted is limited in usage right.

A data transmitting apparatus comprising:

• a transmitting unit connected to a first network and configured to transmit a check packet to a data receiving apparatus using a Transfer Control Protocol (TCP);
• a control unit configured to receive a TCP acknowledgment message to the check packet from the data receiving apparatus, the acknowledgment message including acknowledgment information based on shared data shared with said data receiving apparatus;
• a computing unit configured to compute an expected acknowledgment information based on the shared data shared with said data receiving apparatus;
• a comparing unit configured to produce a comparison result for said data receiving apparatus based on the acknowledgment information and the expected acknowledgment information;
• a timer configured to determine whether a response time of the acknowledgment message is less than a predetermined time;
• and
• a judgment unit configured to judge whether subsequent content data transmitted to said data receiving apparatus will be limited in usage right based on the comparison result and the determination of the timer, if the TCP acknowledgement message is received, the judgment unit determines that the data receiving apparatus is connected to the data transmitting apparatus through a second network, and the subsequent data content data transmitted is limited in usage right.

A data transmitting method, comprising:

• transmitting a check packet to a data receiving apparatus using a Transfer Control Protocol (TCP);
• receiving an acknowledgment message to the check packet from the data receiving apparatus, the acknowledgment message including acknowledgment information based on shared data shared with said data receiving apparatus;
• computing an expected acknowledgement information based on the shared data shared with said data receiving apparatus;
• producing a comparison result for said data receiving apparatus based on the acknowledgment information and the expected acknowledgement information;
• determining whether a response time of the acknowledgment message is less than a predetermined time;
• and
• judging whether subsequent content data transmitted to said data receiving apparatus will be limited in usage right based on the comparison result in the producing step and the determination in the determining step, if the TCP acknowledgement message is received, the judgment unit determines that the data receiving apparatus is connected to the data transmitting apparatus through a second network, and the subsequent data content data transmitted is limited in usage right.

A computer readable storage medium encoded with computer program instructions which cause a computer to execute a method of controlling a data transmission comprising:

• transmitting a check packet to a data receiving apparatus using a Transfer Control Protocol (TCP);
• receiving a TCP acknowledgment message to the check packet from the data receiving apparatus, the acknowledgment message including acknowledgment information based on shared data shared with said data receiving apparatus;
• computing an expected acknowledgement information based on the shared data shared with said data receiving apparatus;
• producing a comparison result for said data receiving apparatus based on the acknowledgment information and the expected acknowledgement information;
• determining whether a response time of the acknowledgment message is less than a predetermined time;
• and
• judging whether subsequent content data transmitted to said data receiving apparatus will be limited in usage right based on the comparison result in the producing step and the determination in the determining step, if the TCP acknowledgement message is received, the judgment unit determines that the data receiving apparatus is connected to the data transmitting apparatus through a second network, and the subsequent data content data transmitted is limited in usage right.

A data transmitting apparatus comprising:

• means for transmitting a check packet to a data receiving apparatus using a Transfer Control Protocol (TCP);
• means for receiving a TCP acknowledgment message to the check packet from the data receiving apparatus, the acknowledgment message including acknowledgment information based on shared data shared with said data receiving apparatus;
• means for computing an expected acknowledgement information based on the shared data shared with said data receiving apparatus;
• means for producing a comparison result for said data receiving apparatus based on the acknowledgment information and the expected acknowledgement information;
• means for determining whether a response time of the acknowledgment message is less than a predetermined time;
• and
• means for judging whether subsequent content data transmitted to said data receiving apparatus will be limited in usage right based on the comparison result and the determination of means for determining, if the TCP acknowledgement message is received, the judgment unit determines that the data receiving apparatus is connected to the data transmitting apparatus through a second network, and the subsequent data content data transmitted is limited in usage right.