Data communication system, backup server, and communication control apparatus

A communication system including a distribution server which distributes a multicast packet for broadcast, a client which receives the multicast packet via a network, a backup server, and a communication control device, wherein

• the backup server comprises:
• a first receiving device which receives the multicast packet from the distribution server;
• a generation device which appends a delay to the received multicast packet and changes a destination of the delayed multicast packet in order to generate a first backup packet and which generates a second backup packet by changing a destination of the received multicast packet without appending a delay;
• and
• a sending device which sends the first backup packet and the second backup packet to the network, wherein
• the communication control device comprises:
• a monitor device which monitors a receiving status of the multicast packet;
• a second receiving device which receives the first backup packet and the second backup packet when the monitor device detects interruption of the receipt of the multicast packet because of a problem;
• a conversion device which changes a destination of the first backup packet and the second backup packet to the destination of the multicast packet;
• and
• a distribution device which distributes the first backup packet and the second backup packet for which the conversion device changed the destination.