Patent ID: 7218611

Claim:
A broadcast apparatus for broadcasting a stream to a reception apparatus, comprising: a request reception section for receiving a proxy request including an identifier assigned to the reception apparatus, a command to be transmitted to the reception apparatus, and an execution start time of the command to be transmitted to the reception apparatus; a timer for keeping a current time; a request determination section for determining whether or not to accept the proxy request received by the request reception section by using the execution start time included in the received proxy request and the current time kept by the timer; a proxy request storage device for storing the proxy request that is determined by the request determination section to be acceptable; a command extraction section for extracting a set of an identifier of the reception apparatus and a command for the reception apparatus from the proxy request stored in the proxy request storage device a plurality of times at a predetermined time interval; a command packet assembler for assembling a command packet from the set of the identifier and the command extracted by the command extraction section; a multiplexer for generating a stream in which the command packet assembled by the command packet assembler is multiplexed; and a transmitter for sending out the stream generated by the multiplexer to a broadcast channel, wherein the request determination section comprises: a first time calculation section for calculating a first amount of time required from when each command packet is sent out until the command packet arrives at the reception apparatus; a second time calculation section for calculating a second amount of time required from when a first command packet is assembled until a last command packet, including the same set of the identifier and the command as the first packet, is assembled; a reference time calculation section for calculating a reference time by which the proxy request from the reception apparatus should arrive at the present reception apparatus, based on the execution start time included in the proxy request received by the request reception section and the first and second amounts of time calculated by the first and second time calculation sections, respectively; and a determination section for determining that the proxy request received by the request reception section is unacceptable if the current time kept by the timer is after the reference time calculated by the reference time calculation section.