Patent ID: 7051100

Claim:
A data communication apparatus performing communication between a terminal device requesting streaming delivery of a piece of information and a delivering apparatus holding at least one piece of information data and performing the streaming delivery of the information data requested by the terminal device, the data communication apparatus comprising: a data storing unit available to store any piece of the information data; a delivery request receiving unit for receiving a delivery request of the streaming delivery of specific information data from the terminal device; a data checking unit for checking if requested information data of which the streaming delivery is requested by the delivery request is stored in the data storing unit, and sending the delivery request to the delivering apparatus if the requested information data is not stored in the data storing unit; a data receiving unit for receiving delivered requested information data which is the requested information data delivered from the delivering apparatus, and judging an existence of missing data within the delivered requested information data; a data delivering unit for performing the streaming delivery of the delivered requested information data received by the data receiving unit to the terminal device; a missing data transmission requesting unit for sending a missing data transmission request to the delivering apparatus for requesting a transmission of the missing data within the delivered requested information data, when the missing data is detected within the delivered requested information data by the data receiving unit; and a missing data receiving unit for receiving the missing data from the delivering apparatus, and wherein the data storing unit stores the delivered requested information data received by the data receiving unit, and stores the missing data received by the missing data receiving unit with relating the missing data to the delivered requested information data; wherein before the data storing unit finishes storing the delivered requested information data, the delivery request receiving unit receives the delivery request of the delivered requested information data from a new terminal device other than the terminal device, and then the data storing unit finishes storing the delivered requested information data without storing a part of the delivered requested information data, the data delivering unit performs the streaming delivery of the delivered requested information data except an unstored part which has not been stored in the data storing unit to the new terminal device, the data checking unit sends an unstored part delivery request for requesting the streaming delivery of the unstored part to the delivering apparatus, the data receiving unit receives the unstored part delivered from the delivering apparatus, and the data delivering unit performs the streaming delivery of the unstored part received by the data receiving unit to the new terminal device.