The communication device has a receiver that receives packets from the first device, a packet identifier that identifies the chunk, which is a data unit in a higher layer, to which said packet belongs, a buffer that stores said packet, and a buffer control unit that reads the packet from the buffer and sends it to the second device as a unit of the chunk. The buffer control unit controls the storing of said packets in said buffer and the discarding of the packets from said buffer, and the transmitter reads the packets from the buffer and transmits them to the second device.