A data transfer control device and a relay device which are suitable for use in the home network environment. For a case of controlling transfer of information data to a receiving node connected with a first physical network from a transmitting node connected with a second physical network, there is provided a data transfer control device connected with the second physical network which has: an establishing unit for establishing a channel in the second physical network for transmitting the information data; a reserving unit for reserving a communication path for transferring the information data transmitted through that channel to another data transfer control device belonging to the first physical network and/or the receiving node; and a commanding unit for commanding the transmitting node to transmit the information data through that channel, by using a protocol depending on the second physical network.