Recently, a home network integrating various transmission routes such as wired local area network (LAN), wireless LAN, WiFi (registered trademark), WiFi Direct, etc. is widely installed in home. Also, as a digital living network alliance (DLNA) guideline is established, various AV devices such as TV receivers or home servers are connected to a home network to transmit or receive content such as an image or voice. Accordingly, contents stored in a home server may be viewed or listened through a TV receiver installed in another room or a tablet terminal moved to a certain place in a house.
Home network may be connected to a wide area network such as the Internet. A TV receiver connected to a home network through an extended IP network may simultaneously received a plurality of contents (data stream) distributed in real time by various content providers. (For example, please see Patent document 1)
A standard protocol specification for distributing content in real time via an IP network includes a real-time transport protocol (RTP)/an RTP control protocol (RTCP) or a real-time streaming protocol (RTSP). In RTP/RTCP or RTSP, a receiving apparatus regularly sends a receiving report to a transmitting apparatus, and the transmitting apparatus changes a transmission rate according to the receiving report sent by the receiving apparatus. Accordingly, particularly in a network interface such as wireless LAN in which a receiving state varies time to time, the transmission rate is optimized according to a varying network environment so that the receiving apparatus may always receive content in an optimal state.
However, in RTP/RTCP or RTSP, since adjustment of a bandwidth between transmitting apparatuses is not specified, if contents are independently distributed in a plurality of sessions, it is a problem that a bandwidth is occupied by a particular session. For example, in a network environment having a bandwidth of 20 Mbps, when a bandwidth of a transmitting apparatus (A) is 19 Mbps, a bandwidth to be allotted to another transmitting apparatus (B) is only 1 Mbps so that the transmitting apparatus (B) cannot distribute content with a sufficient quality. Also, when a transmission rate of the transmitting apparatus (B) varies, packet loss is generated in streaming data of the transmitting apparatus (A). As a result, both the transmitting apparatuses (A) and (B) may not transmit contents with a sufficient quality. Furthermore, when the transmitting apparatus (A) is disconnected, the bandwidth to be allotted to the transmitting apparatus (B) is increased so that the transmitting apparatus (B) can distribute content with a sufficient quality. However, if one desires to receive content again from the transmitting apparatus (A), re-receiving of content takes time because session between the transmitting apparatus (A) and the receiving apparatus (B) needs to be re-established and buffering of data needs to be performed again.