Abstract: A multicast communication system in which a receiving node which has detected a packet loss can make a retransmission request without applying a high load to a transmitting node, all receiving nodes, and the band of the entire network. The transmitting node transmits an explicit multicast data packet including an address list including a plurality of destination addresses and a bitmap indicating whether the data packet has been delivered to the respective destination addresses, to a plurality of the receiving nodes. The receiving node which has detected the packet loss checks an address list and bitmap of another data packet received and selects a receiving node to which the another data packet has been delivered as a retransmission requester. The receiving node which has detected the packet loss creates a unicast retransmission request packet with the selected receiving node as the destination and transmits it to the selected receiving node.

Abstract: Provided is a multicast distribution device for transmitting a packet in which a reception node can easily perform signal synchronization between a plurality of hierarchized data. The multicast distribution device (100) includes an input unit (110), a hierarchy encoding unit (112), a communication control unit (114), a flow rate control unit (116), a reception node sorting unit (118), a hierarchy setting unit (120), a hierarchy information storage unit (122), and a reception node information storage unit (124). The reception node sorting unit (118) decides the order of addresses described in an address list of a packet of each hierarchy in the descending order from the most significant hierarchy to the least significant hierarchy. When deciding the address order for an arbitrary hierarchy, the address order decided in the more significant hierarchy by one step is acquired as it is and after this, the address order of the remaining reception node is decided.