JP6696879B2 - Communication system and communication method - Google Patents

Description

  The present invention relates to a communication system and a communication method.

  In a PON (Passive Optical Network) system, there are a unicast method and a multicast method as a method of transmitting data to a plurality of subscriber terminals accommodated in each of a plurality of ONUs (Optical Network Units) (for example, , Patent Document 1 and Non-Patent Document 1). FIG. 27 is a configuration diagram of a PON system showing an example of the unicast method and the multicast method.

  The PON system includes an OLT (Optical Line Terminal) 420, which is an optical line terminal device on the station side, and four ONUs 430-1 to 430-4, which are terminal devices installed in a subscriber's house. The OLT 420 and the four ONUs 430-1 to 430-4 are connected via an optical fiber 440, which is an optical transmission medium, an optical splitter 450, and optical fibers 441-1 to 441-4. The OLT 420 is connected via a relay NW (Network) 470 to a video transmission device 481 such as a video distribution server that transmits unicast stream data and a video transmission device 482 such as a video distribution server that transmits multicast stream data.

  The unicast method will be described with reference to FIG. The subscriber terminal device 460-1 views the data as a unicast packet with respect to a video transmission device 481 such as a video distribution server that transmits real-time unicast stream data such as live distribution via the ONU 430-1 and the OLT 420. Make a distribution request for the channel (CH # 1). Similarly, the subscriber terminal device 460-2 also sends a viewing channel (CH #) by a unicast packet to a video transmitting device 481 such as a video distribution server that transmits unicast stream data via the ONU 430-2 and the OLT 420. Make a distribution request of 1).

  The video transmission device 481 such as a video distribution server or the like transmits the stream data of the viewing channel (CH # 1) requested by the subscriber terminal device 460-1 and the viewing channel (CH #) requested by the subscriber terminal device 460-2. The stream data of 1) is transmitted by a unicast packet. Upon receiving the unicast packet, the OLT 420 gives the unicast packet a unicast logical link ID (Identification) that is an identifier indicating the ONU in the PON section.

  That is, the OLT 420 gives the unicast logical link ID corresponding to the ONU 430-1 to the stream data of the one viewing channel (CH # 1). Further, the OLT 420 gives the unicast logical link ID corresponding to the ONU 430-2 to the stream data of the other viewing channel (CH # 1). The OLT 420 transfers the stream data to which the unicast logical link ID is added to all the ONUs 430-1 to 430-4.

  If the unicast logical link ID assigned to the unicast packet is not its own unicast logical link ID, the ONUs 430-1 to 430-4 discard the unicast packet. On the other hand, if the unicast logical link ID assigned to the unicast packet is its own unicast logical link ID, the ONUs 430-1 to 430-4 are subscriber terminal devices 460- 1 to 460-4.

  In FIG. 27, only the ONU 430-1 and ONU 430-2, which have requested the distribution of the viewing channel (CH # 1), transfer the unicast packet to the subordinate subscriber terminal devices 460-1 and 460-2. (See, for example, FIG. 16 of Patent Document 1). That is, in the unicast method, the stream data for the number of terminal devices that have requested distribution is transmitted in the PON section.

  Next, the multicast method will be described with reference to FIG. The subscriber terminal device 460-3 requests, via the ONU 430-3 and the OLT 420, a distribution request for the viewing channel (CH # 2) by a multicast packet to the video transmission device 482 such as a video distribution server that transmits the multicast stream data. I do. Similarly, the subscriber terminal device 460-4 also sends a viewing channel (CH # 2) by a multicast packet to the video transmitting device 482 such as a video distribution server that transmits the multicast stream data via the ONU 430-4 and the OLT 420. Request delivery. The video transmission device 482 such as the video distribution server transmits the stream data of the viewing request channel (CH # 2) in a multicast packet. The video transmission device 482 such as the video distribution server transmits a single stream data even when a plurality of subscriber terminal devices 460-3 and 460-4 request distribution of the same viewing channel.

  Upon receiving the multicast packet, the OLT 420 gives the multicast packet a broadcast logical link ID indicating broadcast distribution, and transmits the multicast packet to all the ONUs 430-1 to 430-4 by broadcast distribution. As a result, all the ONUs 430-1 to 430-4 can receive the multicast packet in the PON section.

  When all the ONUs 430-1 to 430-4 receive the multicast packet from the OLT 420, the filtering function discards the received multicast packet if the received multicast packet is not the multicast packet corresponding to the pre-registered terminal address. To do. On the other hand, all the ONUs 430-1 to 430-4, if the received multicast packet is a multicast packet corresponding to the terminal address registered in advance, the subscriber terminal devices 460-1 to 460- that control the received multicast packet. 4 (for example, see FIG. 17 of Patent Document 1). As described above, the multicast method is superior to the unicast method in terms of band utilization efficiency because there is no duplicate transmission of the same channel in the PON section.

JP, 2010-16753, A

Hiroki Ikeda, Atsushi Sugawa, "Implementation and Challenges of IPTV Services Using PON Technology", Communications Society Magazine, No.14 [Autumn Issue], 2010, p10-22

  As described above, in the conventional PON system, when transmitting the stream data of the same channel, that is, the same content, if the multicast method is adopted, stream data is not redundantly transmitted in the PON section and the band is efficiently used. be able to. However, in order to perform the transmission by the multicast method, the subscriber terminal devices 460-1 to 460-4, the relay NW 470, the video transmission devices 481, 482 such as the video distribution server for transmitting the stream data, etc. are compatible with the multicast method. Need to be.

  On the other hand, most of the subscriber terminal devices 460-1 to 460-4 and the video transmission devices 481 and 482 such as the video distribution server support only the universal unicast system and support the multicast system. Absent. Therefore, it is general that the same channels with different destinations, that is, real-time stream data having the same contents are transmitted by the unicast method.

  In the conventional PON system, only multicast packets can be transmitted by the multicast method, and unicast packets cannot be transmitted by the multicast method. Therefore, data having different contents and the same content is transmitted by the unicast method, and there is a problem that duplicate transmission of data occurs in the PON section.

  In view of the above circumstances, it is an object of the present invention to provide a technique capable of avoiding redundant transmission of data having the same content and efficiently using a band.

  One aspect of the present invention is a communication system in which a plurality of subscriber-side optical line terminating devices to which a terminal device is connected and a station-side optical line terminating device are connected by a multiplexer / distributor. When a terminal device connected to any one of the subscriber side optical line terminator transmits a distribution request signal requesting to receive the data from the outside, the device transmits the data having the same content as the other data. When the data is being transmitted to the terminal device, the data corresponding to the distribution request signal is not transmitted, but the data being transmitted is transmitted to the multiplex distributor as a broadcast distribution, and the distribution request is transmitted. When the subscriber side optical line terminal device connected to the terminal device of the signal transmission source receives the data transmitted from the multiplex distributor by broadcast distribution, the destination of the received data is the distribution request. It is a communication system that rewrites and transmits to the terminal address of the terminal device that is the source of the signal.

  One aspect of the present invention is the above communication system, wherein when the station side optical line terminal receives the data from the outside based on the distribution request signal, the same content as the received data is received. It is determined whether the data is being transmitted to the other terminal device, and when it is determined that the data is being transmitted, the data received from the outside based on the distribution request signal is discarded. Alternatively, the distribution request signal is discarded.

  One aspect of the present invention is the communication system as described above, wherein either the station side optical line terminal device or the subscriber side optical line terminal device is transmitted by the terminal device by broadcast distribution. In the case of transmitting a stop request signal for requesting stop of transmission of the data that is present, when the data is being transmitted to the other terminal device, the stop request signal is discarded and the stop request signal is transmitted. A response signal to the stop request signal is transmitted to the terminal device that is the transmission source of.

  One aspect of the present invention is the communication system described above, wherein the subscriber-side optical line terminal device includes data identification information for uniquely identifying the data included in the distribution request signal, and a terminal address of the terminal device. When receiving the data transmitted by the terminal side optical line termination device for broadcast transmission, the data identification information of the received data, the terminal request reference unit detects the When it matches the data identification information, the reception processing unit that rewrites the destination of the data to the terminal address corresponding to the data identification information and transmits the data to the terminal device.

  One aspect of the present invention is the communication system as described above, wherein the station side optical line terminal device includes data identification information for uniquely identifying the data included in the distribution request signal, and a terminal address of the terminal device. A terminal device identification information that uniquely identifies the subscriber-side optical line terminal device to which the terminal device is connected, and a distribution request reference unit that detects the terminal device identification information, and the terminal device identification information detected by the distribution request reference unit. The corresponding optical line terminal device on the subscriber side receives the data identification information detected by the distribution request reference unit and the terminal address of the terminal device from the optical line terminal device on the station side, and the optical line terminal device on the station side is received. When the device receives the data to be transmitted by broadcast distribution, when the data identification information of the received data matches the data identification information detected by the distribution request reference unit, the destination of the data is identified as the data identification. A reception processing unit that rewrites the data to the terminal address corresponding to information and transmits the data to the terminal device.

  One aspect of the present invention is the above communication system, wherein the station side optical line terminal is the same data identification information as the data being transmitted and included in the distribution request signal. When the data having the above is transmitted by broadcast distribution, the subscriber side optical line termination to which the terminal device of the transmission source of the distribution request signal is connected by associating uniquely identifiable identifier information with the data identification information. When the signal processing control unit that transmits the identifier information corresponding to the data identification information to the device, and the identifier information is associated with the data identification information by the signal processing control unit, the identifier information is associated with the data. And a signal processing unit for transmitting by broadcast distribution, wherein the reception processing unit of the subscriber-side optical line termination device transmits data transmitted by the station-side optical line termination device by the broadcast distribution. When receiving, when the identifier information received from the signal processing control unit is not added to the received data, the data is discarded, and when the identifier information is added, the data is taken in and taken in. When the data identification information of the data matches the data identification information included in the distribution request signal, the destination of the data is rewritten to the terminal address corresponding to the data identification information to transfer the data to the terminal device. Send.

  One aspect of the present invention is the communication system described above, wherein the signal processing control unit includes the data identification information included in the distribution request signal, and the data identification included in the data being transmitted by the broadcast distribution. When the information and the information belong to the same predetermined group, the identifier information corresponding to the data identification information included in the data being transmitted by the broadcast distribution is associated with the data identification information included in the distribution request signal. The identifier information corresponding to the data identification information included in the distribution request signal is transmitted to the subscriber-side optical line terminal device connected to the terminal device that is the transmission source of the distribution request signal.

  One aspect of the present invention is a communication method by a communication system in which a plurality of subscriber-side optical line terminators to which a terminal device is connected and a station-side optical line terminator are connected by a multiplexer. When the optical line terminal device transmits a distribution request signal requesting that the terminal device connected to any one of the subscriber side optical line terminal devices receives data from the outside, the same content as the data described above is transmitted. When data is being transmitted to the other terminal device, the data corresponding to the distribution request signal is not transmitted, and the data being transmitted is transmitted to the multiplex distributor as broadcast distribution, When the subscriber-side optical line terminator connected to the terminal device that is the transmission source of the distribution request signal receives the data transmitted from the multiplex distributor by broadcast distribution, the destination of the received data is It is a communication method in which the terminal address of the terminal device that is the transmission source of the distribution request signal is rewritten and transmitted.

  According to the present invention, it is possible to avoid duplication of transmission of data having the same content and efficiently use a band.

FIG. 3 is a block diagram showing a configuration of a communication system and a connection configuration with other devices and the like in the first embodiment. It is a flow chart which shows a flow of processing by an overlapping stream control part in a 1st embodiment. It is a block diagram which shows the structure of a communication system in 2nd Embodiment, and a connection structure with other apparatuses. It is a figure which shows the data structure of the memory | storage part with which the OLT in 2nd Embodiment is equipped. It is a figure which shows the data structure of the memory | storage part with which ONU in 2nd Embodiment is equipped. It is a flowchart which shows the flow of a process by the terminal request reference part in 2nd Embodiment. It is a flow chart which shows a flow of processing by OLT in a 2nd embodiment. It is a flow chart which shows a flow of processing by a reception processing part in a 2nd embodiment. It is a block diagram which shows the structure of a communication system in 3rd Embodiment, and a connection structure with other apparatuses. It is a figure which shows the data structure of the memory | storage part with which the OLT in 3rd Embodiment is equipped. It is a figure which shows the data structure of the memory | storage part with which ONU in 3rd Embodiment is equipped. It is a flow chart which shows a flow of processing by a distribution demand reference part in a 3rd embodiment. It is a flow chart which shows a flow of processing by a signal processing control part in a 3rd embodiment. It is a flow chart which shows a flow of processing by a reception processing part in a 3rd embodiment. It is a block diagram which shows the structure of a communication system in 4th Embodiment, and a connection structure with other apparatuses. It is a figure which shows the data structure of the memory | storage part with which the OLT in 4th Embodiment is equipped. It is a flow chart which shows a flow of processing by a signal processing control part in a 4th embodiment. It is a figure which shows the data structure of the memory | storage part with which ONU in 4th Embodiment is equipped. It is a block diagram which shows the structure of a communication system in 5th Embodiment, and a connection structure with other apparatuses. It is a figure which shows the data structure of the memory | storage part with which the OLT in 5th Embodiment is equipped. It is a flow chart which shows a flow of processing by a signal processing control part in a 5th embodiment. It is a figure which shows the data structure of the memory | storage part with which the OLT in the other structural example of 5th Embodiment is equipped. It is a block diagram which shows the structure of a communication system by another structural example of 5th Embodiment, and a connection structure with another apparatus etc. It is a block diagram which shows the structure of a communication system in 6th Embodiment, and a connection structure with other apparatuses. It is a flowchart which shows the flow of a process by the delivery request reference part in 6th Embodiment. It is a flowchart which shows the flow of a process by the selection part in 6th Embodiment. It is a block diagram which shows the example which applied the unicast system and the multicast system to the structure of the conventional PON system.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows the internal configuration of the communication system 1 according to the first embodiment, the connection configuration of the communication system 1 and the terminal devices 60-1 to 60-3, the connection configuration of the communication system 1 and the relay NW 70, and the relay NW 70 and the server device 80. It is a figure which shows the connection structure of. In the following description, the case where the number of terminal devices 60 is three will be described as an example, but the number of terminal devices 60 may be any number as long as it is two or more.

  The communication system 1 is, for example, a PON system, and IEEE (The Institute of Electrical and Electronics Engineers) such as GE-PON (Gigabit Ethernet (registered trademark) Passive Optical Network) and 10G-EPON (10Gigabit-Ethernet Passive Optical Network). It is a system based on a standard and a system based on ITU-T (International Telecommunication Union Telecommunication Standardization Sector) such as G-PON (Gigabit-Cable Passive Optical Network) and XG-PON (10 Gigabit-Cable Passive Optical Network).

  The communication system 1 includes an OLT 20 which is a station side optical line terminating device, and ONUs 30-1 to 30-3 (subscribers) which are terminating devices installed in subscriber homes of communication services provided using the communication system 1. Side optical line terminator), an optical splitter 50 which is a multiplex distributor, and optical fibers 40 and 41-1 to 41-3 which are optical transmission media. ONU identification information (termination device identification information) that can uniquely identify each of the ONUs 30-1 to 30-3 is provided in advance to the ONUs 30-1 to 30-3. Here, as the ONU identification information, for example, The logical link ID for unicast shall be applied. In the following description, the subscriber of the communication service is also called a user.

  The relay NW 70 is, for example, a communication network such as the Internet, and connects the OLT 20 and the server device 80. Further, among the communication devices such as routers provided in the relay NW 70, the communication device that transmits data to the OLT 20 is the ONU identification information that specifies the ONUs 30-1 to 30-3 that are the transmission destination for the data received from the server device 80. Is added to the OLT 20 by the unicast method. Here, for example, VID (Virtual Local Area network Identifier) is applied as the information corresponding to the ONU identification information.

  The server device 80 is, for example, a video transmitting device such as a video distribution server owned by a video distributor, and a streaming server device or the like for transmitting content data including real-time video and audio such as live distribution is applied. To be done. Further, the server device 80 receives the distribution request signals of the terminal devices 60-1 to 60-3, and uses the unicast method to transmit the content data requested based on the received distribution request signal to the terminal that is the transmission source of the distribution request signal. The data is transmitted to the devices 60-1 to 60-3.

  Content data including real-time video and audio, such as live distribution, is broadcast type data, and is a so-called streaming method, that is, when receiving time-series data such as video and audio, it is played back in parallel with data reception. This is data applied to the method of performing. Further, the time-series data that is the target of the streaming method is called stream data or streaming data, and the content data in this embodiment is broadcast type stream data. Broadcast type stream data means, for example, when the terminal device 60-1 continuously receives content data from the server device 80, the terminal device 60-2 causes the server device 80 to display the content at a certain time. It is assumed that a data distribution request signal is transmitted. At that time, since the server device 80 transmits the content data transmitted at the time to the terminal device 60-2, the content data reproduced by the terminal device 60-1 and the terminal device 60-2 are the same. It becomes the content.

  Content identification information that can be uniquely identified for each content data is given in advance and written in the content data. Here, the content identification information may be any information as long as it can uniquely identify the content of the content data, for example, a distribution request transmitted based on HTTP (Hyper Text Transfer Protocol). A file name or the like may be applied. Further, in the following description, the transmission process in which the server device 80 transmits the content data by receiving the distribution request signals from the plurality of terminal devices 60-1 to 60-3 is also referred to as a distribution process. As a protocol applied to the transmission process, in addition to HTTP and MMS (Microsoft (registered trademark) Media Server protocol), a combination of RTP (Real-time Transport Protocol) and RTSP (Real Time Streaming Protocol) is applied. Although it is assumed, a protocol other than these may be used.

  Each of the terminal devices 60-1 to 60-3 is, for example, a personal computer used by a user, and has a terminal address such as an IP (Internet Protocol) address and a MAC (Media Access Control) address that can be uniquely identified in advance. .. In addition, the terminal devices 60-1 to 60-3 are provided with application software such as a Web browser and Windows (registered trademark) Media Player, and receive and reproduce video and audio data by the unicast method. Also, each of the terminal devices 60-1 to 60-3 is connected to the ONUs 30-1 to 30-3, receives a user's operation, and requests the server device 80 to distribute content data in a unicast manner. In this case, the distribution request signal including the content identification information of the content data is transmitted. In addition, each of the terminal devices 60-1 to 60-3 transmits a stop request signal including content identification information of the content data when requesting the stop of distribution of the content data in response to a user operation.

  In the communication system 1, the optical splitter 50 distributes the data received from the OLT 20 via the optical fiber 40 into three and transmits the data to the ONUs 30-1 to 30-3 via the optical fibers 41-1 to 41-3. Further, the optical splitter 50 multiplexes the data received from the terminal devices 60-1 to 60-3 via the ONUs 30-1 to 30-3 and transmits the multiplexed data to the OLT 20 via the optical fiber 40.

  The OLT 20 includes a duplicate stream inhibiting unit 21. When the content data is received from the server device 80 via the relay NW 70, the duplicate stream suppressing unit 21 determines whether or not the content data having the same content exists among the content data already transmitted. Further, when determining that the content data having the same content exists, the duplicate stream inhibiting unit 21 selects one content data from the duplicate content data and discards the other content data. Further, the duplicate stream inhibiting unit 21 adds the broadcast logical link ID to the selected content data and transmits the content data to the ONUs 30-1 to 30-3 by broadcast distribution.

  Each of the ONUs 30-1 to 30-3 includes stream adjusting units 31-1 to 31-3. When the stream adjustment units 31-1 to 31-3 receive the content data transmitted by the broadcast distribution, the content identification information included in the content data is transmitted by the connected terminal devices 60-1 to 60-3. It is determined whether or not it matches the content identification information included in the distribution request signal. In addition, the stream adjusting units 31-1 to 31-3 discard the received content data when determining that the content identification information does not match.

  If the stream adjustment units 31-1 to 31-3 determine that the content identification information matches, the stream adjustment units 31-1 to 31-3 capture the content data, and the destination terminal address that is the destination of the content data is the terminal that is the transmission source of the distribution request signal. It is determined whether the terminal addresses of the devices 60-1 to 60-3 match. When the stream adjusting units 31-1 to 31-3 determine that the terminal addresses match, the stream adjusting units 31-1 to 31-3 transmit the captured content data to the terminal devices 60-1 to 60-3. If the stream adjusting units 31-1 to 31-3 determine that the terminal addresses do not match, the stream adjusting units 31-1 to 31-3 rewrite the destination terminal address with the terminal addresses of the terminal devices 60-1 to 60-3 that are the transmission source of the distribution request signal. Then, the content data is transmitted to the terminal devices 60-1 to 60-3.

(Processing to which the communication system 1 of the first embodiment is applied)
Next, a flow of processing to which the communication system 1 of the first embodiment is applied will be described with reference to FIGS. 1 and 2. FIG. 2 is a flowchart showing the flow of processing by the duplicate stream inhibiting unit 21. In response to the user's operation, the terminal device 60-1 transmits a distribution request signal including the content identification information of the content # 1 to the server device 80. Upon receiving the distribution request signal from the terminal device 60-1, the ONU 30-1 transmits the distribution request signal to the OLT 20 via the optical splitter 50.

  Upon receiving the distribution request signal from the ONU 30-1, the OLT 20 transmits the distribution request signal to the server device 80 via the relay NW 70 (step P1 in FIG. 1). The server device 80 transmits the content data of the content # 1 corresponding to the content identification information included in the distribution request signal to the relay NW 70 by the unicast method. The communication device included in the relay NW 70 adds the VID of the ONU 30-1 that has transmitted the distribution request signal to the content data received from the server device 80, and transmits the content data to the OLT 20.

  The duplicate stream inhibiting unit 21 of the OLT 20 receives the content data from the relay NW 70 (step S1 in FIG. 2). The duplicate stream inhibiting unit 21 determines whether or not content data having the same content has already been transmitted. That is, the duplicate stream suppressing unit 21 refers to the content identification information included in the content data and determines whether or not other content data including the content identification information that matches the content identification information is being transmitted (FIG. 2). Step S2). Here, since the other content data is not transmitted, the duplicate stream suppressing unit 21 determines that the other content data having the same content identification information is not transmitted (step S2-No in FIG. 2). The duplicate stream suppressing unit 21 adds the unicast logical link ID assigned to the ONU 30-1 to the content data and transmits the content data to the ONUs 30-1 to 30-3 (step S3 in FIG. 2).

  When the stream adjusting unit 31-1 of the ONU 30-1 receives the content data, the unicast logical link ID assigned to the ONU 30-1 is assigned to the stream adjusting unit 31-1. Send to 1. The terminal device 60-1 receives the content data from the ONU 30-1 and starts reproduction. The stream adjusting units 31-2 and 31-3 of the ONUs 30-2 and 30-3 use the unicast logical link ID assigned to the received content data as the unicast logical link ID assigned to itself. Since it does not exist, the received content data is discarded.

  In the above state, the terminal device 60-2 transmits the distribution request signal including the content identification information of the content # 1 to the server device 80 in response to the user's operation (step P2 in FIG. 1). The server device 80 transmits the content data of the content # 1 corresponding to the content identification information included in the distribution request signal to the relay NW 70 by the unicast method. The communication device included in the relay NW 70 adds the VID of the ONU 30-2 that has transmitted the distribution request signal to the content data received from the server device 80, and transmits the content data to the OLT 20.

  The duplicate stream inhibiting unit 21 of the OLT 20 receives the content data from the relay NW 70 (step S1 in FIG. 2). The duplicate stream suppressing unit 21 refers to the content identification information included in the content data and determines whether or not other content data including the content identification information that matches the content identification information is being transmitted (step in FIG. 2). S2). Here, since the content data of the content # 1 has already been transmitted to the terminal device 60-1, the duplicate stream suppressing unit 21 determines that other content data having the same content identification information is transmitted. (Step S2-Yes in FIG. 2).

  The duplicate stream inhibiting unit 21 selects any one of the duplicate content data and discards the other content data (step S4 in FIG. 2). Here, it is assumed that the content data transmitted to the terminal device 60-1 is selected and the content data addressed to the terminal device 60-2 is discarded. The duplicate stream suppressing unit 21 assigns a broadcast logical link ID to the content data being transmitted to the selected terminal device 60-1, and transmits the content data to the ONUs 30-1 to 30-3 as broadcast distribution. (Step S5 of FIG. 2).

  Upon receiving the content data, the stream adjusting units 31-1 to 31-3 of the ONUs 30-1 to 30-3 take in the content data because the broadcast logical link ID is assigned. In the ONU 30-1 and the ONU 30-2, the content identification information included in the captured content data matches the content identification information included in the distribution request signal transmitted by the terminal device 60-1 and the terminal device 60-2 connected to each. In order to do so, the fetched content data is transmitted to the terminal device 60-1 and the terminal device 60-2 connected to each. When transmitting, since the destination terminal address of the content data is the terminal address of the terminal device 60-1, the ONU 30-2 rewrites the destination terminal address to the terminal address of the terminal device 60-2 and transmits. .. On the other hand, since the terminal device 60-3 connected to the ONU 30-3 has not transmitted the distribution request signal, the ONU 30-3 discards the captured content data.

  With the configuration of the first embodiment described above, the duplicate stream inhibiting unit 21 of the OLT 20 selects any one content data when the content data received from the server device 80 and the content data having the same content have already been transmitted. And discard other content data. As a result, in the section of the communication system 1, the terminal device 60-1 and the terminal device 60-2 that have transmitted the distribution request signal receive and reproduce the content data without redundantly transmitting the same content data. It becomes possible to do it. Therefore, in the section of the communication system 1, it is possible to avoid redundant transmission of data having the same content and efficiently use the band.

  In addition, in the above-described first embodiment, the duplicate stream suppressing unit 21 determines the newly received terminal device 60-2 instead of the content data already transmitted to the terminal device 60-1 in step S4 of FIG. It is assumed that the content data to be the destination is selected. In this case, the duplicate stream suppressing unit 21 switches the content data to be transmitted to the terminal device 60-1. When the packet forming the content data includes a sequence number indicating the order, the duplicate stream suppressing unit 21 sets the sequence number to start discarding in the content data being transmitted to the terminal device 60-1. Detect it. Then, in the newly selected content data, the duplicate stream suppression unit 21 transmits from the packet of the sequence number at which the discard is started, so that the content data reproduced in the terminal device 60-1 is not interrupted. can do.

  Further, in order to reduce the load caused by continuously receiving the content data to be discarded from the server device 80, the duplicate stream suppressing unit 21 transmits a stop request signal to the server device 80 to transmit the content data. It may be stopped.

(Second embodiment)
FIG. 3 illustrates the internal configuration of the communication system 1a, the connection configuration of the communication system 1a and the terminal devices 60-1 to 60-3, the connection configuration of the communication system 1a and the relay NW70, and the relay NW70 and the server device 80 in the second embodiment. 3 is a block diagram showing the connection configuration of FIG. The same configurations as those in the first embodiment are designated by the same reference numerals, and different configurations will be described below.

  The communication system 1a includes an OLT 20a, ONUs 30a-1 to 30a-3, an optical splitter 50, and optical fibers 40, 41-1 to 41-3. The OLT 20a includes a duplicate stream inhibiting unit 21a, and the duplicate stream inhibiting unit 21a includes a distribution status sharing unit 211, a selecting unit 212, a signal processing unit 213, a signal processing control unit 214, and a storage unit 215. Each of the ONUs 30a-1 to 30a-3 includes stream adjusting units 31a-1 to 31a-3, and each of the stream adjusting units 31a-1 to 31a-3 includes terminal request reference units 311-1 to 311-. 3, storage units 312-1 to 312-3, and reception processing units 313-1 to 313-3.

  In the duplicate stream inhibiting unit 21a, the distribution status sharing unit 211 registers the terminal address, the content identification information, and the ONU identification information from the terminal request reference units 311-1 to 311-3 of any of the ONUs 30a-1 to 30a-3. Information indicating that the terminal address and the content identification information have been deleted is received. Further, the distribution status sharing unit 211 transmits the received information to all the terminal request reference units 311-1 to 311-3.

  The storage unit 215 stores the PON section identifier information data 2151 shown in FIG. In the PON section identifier information data 2151, PON section identifier information is written. Here, the PON section identifier information includes information indicating the PON section identifier and information indicating the value of the PON section identifier, and is set in advance by the operator or the like of the communication system 1a. The information indicating the PON section identifier is information indicating in which field of the header information included in the content data the value of the PON section identifier is written. For example, the position of the field in the header information is The information may be information directly indicated by the number of bits or the number of bytes, or may be information indicating a field name such as the destination MAC address of the MAC address field or the destination IP address of the IP address.

  The PON section identifier is referred to only between the OLT 20a and the ONUs 30a-1 to 30a-3, and is used, for example, when designating the ONUs 30a-1 to 30a-3 from which the content data is taken. For example, the OLT 20a sets the destination address of the field of the MAC address as the information indicating the PON section identifier in advance to the ONU 30a-1 and the ONU 30a-2, and sets the MAC address A as the value of the PON section identifier. The identifier information for the PON section that specifies that is notified. On the other hand, the OLT 20a does not notify the ONU 30a-3 of the PON section identifier information.

  When transmitting the content data, the OLT 20a writes the MAC address A in the field of the destination MAC address and transmits the content data. Upon receiving the content data, the ONU 30a-1 and the ONU 30a-2 refer to the destination MAC address and detect that the MAC address A is written, and fetch the content data. On the other hand, since the ONU 30a-3 has not received the notification of the PON section identifier information, the ONU 30a-3 discards the content data without capturing it. By doing so, the ONUs 30a-1 to 30a-3 to which the content data is taken can be specified in advance, and the same PON section identifier information is associated with a certain content data group, The destination can also be selected in units of content data groups or the like.

  When the selection unit 212 receives the content data from the server device 80 via the relay NW 70, the content data having the same content, that is, the content data having the same content identification information is transmitted to the ONUs 30a-1 to 30a-3 by the signal processing unit 213. It is determined whether or not there is. In addition, when the selection unit 212 determines that the content data having the same content is transmitted by the signal processing unit 213, the selection unit 212 discards the received content data. Further, when the content data being transmitted is not transmitted by the broadcast distribution, the selection unit 212 outputs the content identification information of the content data to the signal processing control unit 214 in order to transmit the content data by the broadcast distribution. To do.

  The signal processing control unit 214 reads the PON section identifier information from the PON section identifier information data 2151 of the storage unit 215, and transmits the read PON section identifier information to the ONUs 30a-1 to 30a-3. Further, the signal processing control unit 214 receives the content identification information output by the selection unit 212, outputs the content identification information and the read PON section identifier information in association with each other to the signal processing unit 213.

  The signal processing unit 213 acquires the content data output by the selection unit 212. Further, the signal processing unit 213 acquires information in which the content identification information output by the signal processing control unit 214 and the PON section identifier information are associated with each other. The signal processing unit 213 also detects content data including the content identification information acquired from the signal processing control unit 214. Further, the signal processing unit 213 identifies the field corresponding to the information indicating the PON section identifier of the header information included in the detected content data, based on the PON section identifier information corresponding to the content identification information. In addition, the signal processing unit 213 rewrites the value of the specified field with the value of the PON section identifier included in the PON section identifier information, and transmits the content data.

  In the stream adjusting units 31a-1 to 31a-3 included in each of the ONUs 30a-1 to 30a-3, the storage units 312-1 to 312-3 store the data illustrated in FIG. FIG. 5 shows the data stored in the storage unit 312-1 as an example, and the other storage units 312-2 and 312-3 also store data having the same configuration.

  The storage unit 312-1 stores a terminal management table 3121-1 and PON section identifier information data 3122-1. The terminal management table 3121-1 has items of “terminal address”, “content identification information”, and “ONU identification information”. The terminal address given to each of the terminal devices 60-1 to 60-3 is written in the item "terminal address". Content identification information is written in the "content identification information" item. The ONU identification information of the ONUs 30a-1 to 30a-3 is written in the "ONU identification information" item. The PON section identifier information described above is written in the PON section identifier information data 3122-1.

  The terminal request reference units 311-1 to 311-3 refer to information included in the distribution request signal and the stop request signal transmitted by the terminal devices 60-1 to 60-3. In addition, the terminal request reference units 311-1 to 311-3 detect the terminal addresses of the terminal devices 60-1 to 60-3 that are transmission sources and the content identification information included in the distribution request signal or the stop request signal. Further, when referring to the distribution request signal, the terminal request reference units 311-1 to 311-3 include the ONU identification information of the ONUs 30a-1 to 30a-3 corresponding to the detected terminal address and the content identification information, respectively. Correspondingly, it writes in the terminal management table 3121-1 to 3121-3 of the memory | storage part 312-1 to 312-3 corresponding to each.

  Further, when the terminal request reference units 311-1 to 311-3 refer to the stop request signal, the terminal request reference units 311-1 to 311-3 detect the terminal management tables 3121-1 to 3121-3 of the storage units 312-1 to 312-3 corresponding to the respective stop request signals. The record corresponding to the selected terminal address and the content identification information is deleted. Further, the terminal request reference units 311-1 to 311-3 provide the distribution status sharing unit 211 with information indicating registration of the terminal address, content identification information, and ONU identification information, and information indicating deletion of the terminal address and content identification information. Send.

  When the stop request signal is referred to, the terminal request reference units 311-1 to 311-3 transmit the content data corresponding to the content identification information included in the stop request signal to the terminal device 60-1 which is the transmission source of the stop request signal. If the terminal devices 60-1 to 60-3 other than the terminal devices 60 to 60-3 have received the signal, the stop request signal is discarded. When the terminal request reference units 311-1 to 311-3 discard the suspension request signal, the server device 80 transmits a response to the suspension request signal to the source terminal devices 60-1 to 60-3. The same response signal as the signal is transmitted.

  Also, the terminal request reference units 311-1 to 311-3 register the terminal address, the content identification information, and the ONU identification information transmitted from the distribution status sharing unit 211 by the other terminal request reference units 311-1 to 311-3. And information indicating deletion of the terminal address and the content identification information are received. Also, the terminal request reference units 311-1 to 311-3 store the corresponding storage units 312-1 to 312-3 based on the received information indicating the registration of the terminal address, the content identification information, and the ONU identification information. Write in the terminal management tables 3121-1 to 3121-3. Further, the terminal request reference units 311-1 to 311-3, based on the received terminal address and the information indicating the deletion of the content identification information, the terminal management table 3121 of the storage units 312-1 to 312-3 corresponding to each. Corresponding records are deleted from -1 to 3121-3.

  The reception processing units 313-1 to 313-3 receive the PON section identifier information from the signal processing control section 214, and the PONs of the storage sections 312-1 to 312-3 corresponding to the received PON section identifier information, respectively. Write in the section identifier information data 3122-1 to 3122-3. Further, when the reception processing units 313-1 to 313-3 receive the content data from the signal processing unit 213, if the content data is transmitted by broadcast distribution, the PON section identifier information data 3122-1 to 3122. The PON section identifier information written in -3 is read out. Further, when the value of the read PON section identifier information and the value of the PON section identifier of the header information included in the content data match, the reception processing units 313-1 to 313-3 fetch the content data. ..

  In addition, the reception processing units 313-1 to 313-3 are contents in which the fetched content data is requested to be distributed by the terminal devices 60-1 to 60-3 connected to the corresponding ONU 30a-1 to ONU 30a-3. Whether or not it is data is determined based on the content identification information. In addition, when the reception processing units 313-1 to 313-3 determine that the content data has been requested to be distributed, the reception processing units 313-1 to 313-3 refer to the terminal management tables 3121-1 to 3121-3 to refer to the destination terminals of the content data. The address is rewritten to the terminal address of the transmission source of the distribution request signal, and the content data is transmitted.

(Processing by the terminal request reference unit of ONU)
Hereinafter, a process to which the communication system 1a according to the second embodiment is applied will be described with reference to FIGS. 3 and 6 to 8. FIG. 6 is a flowchart showing the flow of processing performed by the terminal request reference units 311-1 to 311-3 of the ONUs 30a-1 to 30a-3. Hereinafter, as an example, a process performed by the terminal request reference unit 311-1 of the ONU 30a-1 will be described.

  The terminal request reference unit 311-1 receives the request signal transmitted by the terminal device 60-1 (step Sa1). The terminal request reference unit 311-1 determines whether the request signal is a distribution request signal or a stop request signal (step Sa2). For example, it is assumed that the terminal device 60-1 connected to the ONU 30a-1 including the terminal request reference unit 311-1 transmits a distribution request signal including the content # 1 as the content identification information to the ONU 30a-1.

  In this case, the terminal request reference unit 311-1 determines that the distribution request signal has been received (step Sa2, distribution request), and reads the terminal address (#a) and the content identification information (content # 1) from the distribution request signal. .. The terminal request reference unit 311-1 uses the read terminal address (#a) and content identification information (content # 1) as “terminal address” and “content identification information” in the terminal management table 3121-1 of the storage unit 312-1. Create a record by writing in the item. The terminal request reference unit 311-1 further writes and stores the ONU identification information (ONU # 1) of the ONU 30a-1 including itself in the "ONU identification information" item of the record (step Sa3).

  The terminal request reference unit 311-1 sends information indicating the registration of the terminal address (#a), the content identification information (content # 1), and the ONU identification information (ONU # 1) by the control signal 101 to the distribution status sharing unit 211 of the OLT 20a. To (step Sa4). The terminal request reference unit 311-1 transmits a distribution request signal to the duplicate stream suppression unit 21a of the OLT 20a (step Sa5).

  In step Sa4, the terminal request reference unit 311-1 shares the distribution status of the information indicating the registration of the terminal address (#a), the content identification information (content # 1) and the ONU identification information (ONU # 1) by the control signal 101. It is transmitted to the section 211. The distribution status sharing unit 211 transmits the received control signal 101 to the terminal request reference units 311-1 to 311-3 of all the ONUs 30a-1 to 30a-3. When receiving the control signal 101, the terminal request reference units 311-2 and 311-3 receive the control signal 101, the terminal address (#a), the content identification information (content # 1), and the ONU identification information (ONU # 1) included in the control signal 101. ) Is written in the items of “terminal address”, “content identification information”, and “ONU identification information” of the terminal management tables 3121-2 and 3121-3 corresponding to each. At this time, the terminal request reference unit 311-1 may overwrite the information included in the received control signal 101 with the information written in the terminal management table 3121-1 in step Sa3, or the same information may already be written. However, overwriting does not have to be performed.

  As described above, the distribution status sharing unit 211 performs a process of transmitting the received control signal 101 to the terminal request reference units 311-1 to 311-3 of all the ONUs 30a-1 to 30a-3. By the processing, in all the ONUs 30a-1 to 30a-3, the terminal address and the content identification information included in the distribution request signal transmitted from the terminal devices 60-1 to 60-3, and the ONU 30a- which transmitted the distribution request signal. Information associated with the ONU identification information of 1 to 30a-3 can be shared.

  On the other hand, when the terminal device 60-1 transmits the stop request signal including the content identification information of the content # 1, the terminal request reference unit 311-1 receives the request signal as the stop request signal in step Sa2. (Step Sa2, stop request). The terminal request reference unit 311-1 detects the terminal address (#a) and the content identification information (content # 1) of the terminal device 60-1 from the received stop request signal. The terminal request reference unit 311-1 deletes a record corresponding to the detected terminal address (#a) and content identification information (content # 1) from the terminal management table 3121-1 (step Sa6). By deleting the record, the reception processing unit 313-1 stops transmitting the content data of the content identification information (content # 1) to the terminal device 60-1.

  The terminal request reference unit 311-1 transmits information indicating deletion of the terminal address (#a) and the content identification information (content # 1) to the distribution status sharing unit 211 by the control signal 101 (step Sa7). The terminal request reference unit 311-1 refers to the terminal management table 3121-1 and stores the content identification information (content # 1) included in the stop request signal in association with another terminal address. It is determined whether or not there is (step Sa8). When the terminal request reference unit 311-1 determines that the content identification information (content # 1) included in the stop request signal is not stored in association with another terminal address (step Sa8-No). , And sends a stop request signal to the OLT 20a (step Sa11). As a result, the server device 80 stops the transmission of the content data of the content # 1.

  On the other hand, when the terminal request reference unit 311-1 determines that the content identification information (content # 1) included in the stop request signal is stored in association with another terminal address (step Sa8- Yes), the stop request signal is discarded (step Sa9). The terminal request reference unit 311-1 transmits the same response signal as the response signal transmitted by the server apparatus 80 in response to the stop request signal, to the terminal device 60-1 which is the transmission source of the stop request signal (step Sa10). ..

  In step Sa7, the terminal request reference unit 311-1 transmits information indicating deletion of the terminal address (#a) and the content identification information (content # 1) to the distribution status sharing unit 211 by the control signal 101. The distribution status sharing unit 211 transmits the received control signal 101 to the terminal request reference units 311-1 to 311-3 of the ONUs 30a-1 to 30a-3. Upon receiving the control signal 101, the terminal request reference units 311-2 and 311-3 each provide a record corresponding to the terminal address (#a) and the content identification information (content # 1) included in the control signal 101. It is deleted from the corresponding terminal management tables 3121-2 and 3121-3. The process shown in FIG. 6 is performed by the terminal request reference units 311-2 and 311-3 by receiving the distribution request signal and the stop request signal from the corresponding terminal devices 60-2 and 60-3. .

(Processing in OLT)
FIG. 7 is a flowchart showing the flow of processing performed by the selection unit 212, the signal processing control unit 214, and the signal processing unit 213 of the OLT 20a. The broken line in FIG. 7 is a line showing the relevance of the processing of each functional unit. In FIG. 3, when any of the terminal devices 60-1 to 60-3 transmits, for example, a distribution request signal including the content identification information of the content # 1, the distribution request signal is transmitted to the ONUs 30a-1 to 30a-3. It is received by the duplicate stream inhibiting unit 21a of the OLT 20a via the terminal request reference units 311-1 to 311-3. The duplicate stream suppression unit 21a transmits a distribution request signal to the server device 80 via the relay NW 70. The server device 80 starts transmitting the content data of the content # 1 to the terminal devices 60-1 to 60-3 that are the transmission source of the distribution request signal. The selection unit 212 of the duplicate stream suppression unit 21a receives the content data (step Sa21).

  The selection unit 212 refers to the content identification information (content # 1) included in the received content data, and the signal processing unit 213 determines whether or not the content data having the same content identification information is transmitted (step Sa22). Since the content data has been transmitted to the signal processing unit 213 through the selection unit 212, the selection unit 212 can make the determination by referring to the content identification information of the content data transmitted by itself. When the signal processing unit 213 determines that the content data having the same content identification information is transmitted (step Sa22-Yes), the selection unit 212 discards the received content data (step Sa23).

The selection unit 212 determines whether the content identification information (content # 1) that is the determination target in step Sa22 is the same, and the content data being transmitted is broadcast transmission (step Sa24). . When the selection unit 212 determines that the content data being transmitted is transmission by broadcast distribution (step Sa24-Yes), the processing is ended.
On the other hand, when the selection unit 212 determines that the content data being transmitted is not the transmission by the broadcast distribution (step Sa24-No), the content identification information (content # 1) included in the content data is sent to the signal processing control unit. It outputs to 214, and a process is complete | finished (step Sa26).

  On the other hand, when the selection unit 212 determines in step Sa22 that the content data having the same content identification information is not transmitted (step Sa22-No), it outputs the received content data to the signal processing unit 213 (step Sa25). ). The selection unit 212 outputs the content identification information (content # 1) included in the content data to the signal processing control unit 214 and ends the processing (step Sa26).

  For example, when the OLT 20a is activated, the signal processing control unit 214 reads the PON section identifier information (# α) from the PON section identifier information data 2151 of the storage unit 215, and the ONUs 30a-1 to 30a-in response to the control signal 102. 3 to the reception processing units 313-1 to 313-3 (step Sa31). The reception processing units 313-1 to 313-3 of the ONUs 30a-1 to 30a-3 use the received PON section identifier information (# α) for the PON sections of the corresponding storage units 312-1 to 312-3. Write in the identifier information data 3122-1 to 3122-3.

  In step Sa26, the signal processing control unit 214 acquires the content identification information (content # 1) output by the selection unit 212, associates the read PON section identifier information (# α) with the content identification information, and performs signal processing. It is output to the unit 213 (step Sa32).

  The signal processing unit 213 acquires the content data output by the selection unit 212 in step Sa25 (step Sa41). At this time, the signal processing unit 213 stores, for example, the received content data in a buffer or the like until the next process is performed. In step Sa32, the signal processing unit 213 acquires the content identification information (content # 1) output by the signal processing control unit 214 and the PON section identifier information (# α) (step Sa42). The signal processing unit 213 detects the content data corresponding to the content identification information (content # 1) received from the selection unit 212 from the content data acquired from the selection unit 212 (step Sa43).

  The signal processing unit 213 reads out information indicating the PON section identifier from the PON section identifier information associated with the content identification information and information on the value of the PON section identifier. The signal processing unit 213 identifies the corresponding field of the detected content data based on the information indicating the read PON section identifier, and changes the value of the field by rewriting the value of the read PON section identifier. (Step Sa44). The signal processing unit 213 adds a broadcast logical link ID to the content data and transmits the content data to the ONUs 30a-1 to 30a-3 (step Sa45).

  In addition, in the process of step Sa22 performed by the selection unit 212, when the selection unit 212 determines that the content data having the same content identification information is transmitted, the process of step Sa25 is not performed. In this case, the processing in step Sa41 performed by the signal processing unit 213 indicates the processing in which the signal processing unit 213 continuously acquires the content data that has already been acquired from the selection unit 212 and transmitted. The processing after Sa42 is also performed on the content data that is continuously acquired.

(Processing by ONU reception processing unit)
FIG. 8 is a flowchart showing the flow of processing performed by the reception processing units 313-1 to 313-3 of the ONUs 30a-1 to 30a-3. The processing performed by the reception processing unit 313-1 will be described below as an example. The reception processing unit 313-1 receives the content data transmitted by the signal processing unit 213 of the OLT 20a (step Sa51). The reception processing unit 313-1 refers to the logical link ID added to the received content data to determine the distribution method (step Sa52).

  When the reception processing unit 313-1 determines that the added logical link ID is the unicast logical link ID (step Sa52, unicast (individual)), the reception processing unit 313-1 adds the unicast added to the received content data. By determining whether or not the cast logical link ID is the unicast logical ID of the own ONU 30a-1, it is determined whether or not the content data is addressed to the own ONU 30a-1 (step Sa53). When the reception processing unit 313-1 determines that the unicast logical ID added to the received content data is not the unicast logical ID of the ONU 30a-1 itself (step Sa53-No), the received content data is received. Is discarded and the process ends (step Sa56). On the other hand, when the reception processing unit 313-1 determines that the unicast logical ID attached to the received content data is the unicast logical link ID of the ONU 30a-1 itself (step Sa53-Yes), The received content data is fetched, transmitted to the terminal device 60-1, and the processing ends (step Sa54).

  In step Sa52, when the reception processing unit 313-1 determines that the assigned logical link ID is the broadcast logical link ID (step Sa52, broadcast (broadcast)), the PON of the storage unit 312-1 is determined. The information indicating the PON section identifier and the value of the PON section identifier are read from the section identifier information data 3122-1. The reception processing unit 313-1 refers to the value of the PON section identifier of the header information included in the received content data, based on the read information indicating the PON section identifier. The reception processing unit 313-1 determines whether the value of the PON section identifier included in the referenced header information matches the value of the PON section identifier read from the PON section identifier information data 3122-1. (Step Sa55).

  When the reception processing unit 313-1 determines that the values of the PON section identifiers do not match (No in step Sa55), the reception content unit 313-1 discards the received content data and ends the processing (step Sa56). On the other hand, if the reception processing unit 313-1 determines that the values of the PON section identifiers match (step Sa55-Yes), the reception processing section 313-1 takes in the content data (step Sa57).

  The terminal management table 3121-1 of the storage unit 312-1 also includes information on the terminal devices 60-2 and 60-3 connected to the ONUs 30a-2 and 30a-3 other than the ONU 30a-1. Therefore, the reception processing unit 313-1 refers to the terminal management table 3121-1, and the ONU identification information stored in the “ONU identification information” item is the ONU identification information of the ONU 30a-1 equipped with itself. Extract records. The reception processing unit 313-1 reads the content identification information of the item “content identification information” of the extracted record, and determines whether the read content identification information matches the content identification information included in the imported content data. The determination is made (step Sa58).

  When the reception processing unit 313-1 determines that the content identification information does not match (step Sa58-No), it discards the received content data and ends the processing (step Sa56). When the reception processing unit 313-1 determines that the content identification information matches (Yes in step Sa58), the terminal written in the "terminal address" item of the record extracted from the terminal management table 3121-1 in step Sa58. Read address. The terminal address is the terminal address of the terminal device 60-1 that has transmitted the distribution request signal including the content identification information and that is connected to the ONU 30a-1 equipped with itself.

  The reception processing unit 313-1 rewrites the destination terminal address of the received content data with the read terminal address and transmits the content data to the terminal device 60-1 (step Sa59). The processing shown in FIG. 8 is performed by the reception processing units 313-2 and 313-3 when the content data is received.

  According to the configuration of the second embodiment described above, first, when the content data is not transmitted, the distribution request signal including the content identification information of the content # 1 requested by the terminal device 60-1 is transmitted. (Step Pa1 in FIG. 3), the content data of the content # 1 is transmitted from the server device 80 by the broadcast distribution. Further, all the ONUs 30a-1 to 30a-3 receive the same PON section identifier information from the signal processing control unit 214 and write it in the corresponding PON section identifier information data 3122-1 to 3122-3. I remember it. Therefore, when the processes of steps Sa51 to Sa57 of FIG. 8 are performed, the reception processing unit 313-1 determines that the content identification information matches in the determination of step Sa58, and the reception processing units 313-2 and 313-3 , It is determined that the content identification information does not match. As a result, only the reception processing unit 313-1 performs the process of step Sa59, and the content data is transmitted only to the terminal device 60-1.

  In this state, when the distribution request signal including the content identification number of the content # 1 is transmitted from the terminal device 60-2 (step Pa2 in FIG. 3), the terminal request reference unit 311-2 is based on the distribution request signal. Creates a new record in the terminal management table 3121-1 of the storage unit 312-2 by the process of step Sa3 of FIG. That is, the terminal request reference unit 311-2 includes the terminal address (#b) of the terminal device 60-2 and the content identification information (for each of the items “terminal address”, “content identification information”, and “ONU identification information”). The content # 1) and the ONU identification information (ONU # 2) of the ONU 30a-2 are written to generate a new record.

  Based on the distribution request signal transmitted by the terminal device 60-2, the selection unit 212 of the OLT 20a determines that the content data having the same content identification information is transmitted in the process of step Sa22 of FIG. The selection unit 212 of the OLT 20a discards the content data transmitted from the server device 80 based on the distribution request signal transmitted by the terminal device 60-2 by the process of step Sa23, and the content data of the content # 1 has already been broadcast. Since it has been transmitted by distribution, the processing by the selection unit 212 ends. In this case, since the content data transmitted from the server device 80 based on the distribution request signal transmitted by the terminal device 60-2 is discarded, the signal processing control unit 214 processes the content data in step Sa32 of FIG. The signal processing unit 213 does not perform steps Sa41 to Sa45.

  The reception processing unit 313-2 generates a new record in the terminal management table 3121-1, that is, a record of the terminal address (#b), the content identification information (content # 1), and the ONU identification information (ONU # 2). Therefore, in the process of step Sa58 in FIG. 8, it is determined that the content identification information matches. The reception processing unit 313-2 rewrites the destination terminal address of the fetched content data with the terminal address (#b) included in the new record, and transmits the content data to the terminal device 60-2. This makes it possible to avoid duplication of transmission of data having the same content and efficiently use the band in the section of the communication system 1b.

  Further, in this state, even if the stop request signal including the content identification information of the content # 1 is transmitted from the terminal device 60-1, in the determination in step Sa8 of FIG. 6, the terminal request reference unit 311-1 determines that the content Since the terminal address (#b) is associated with the content identification information of # 1, the determination of “Yes” is made assuming that there is the terminal device 60-2 that is receiving the content data of the content # 1. The terminal request reference unit 311-1 advances the processing of steps Sa9 and Sa10, stops only the transmission of the content data to the terminal device 60-1, and continues the transmission of the content data to the terminal device 60-2. Can be made

(Third Embodiment)
FIG. 9 shows the internal configuration of the communication system 1b, the connection configuration of the communication system 1b and the terminal devices 60-1 to 60-3, the connection configuration of the communication system 1b and the relay NW70, and the relay NW70 and the server device 80 in the third embodiment. 3 is a block diagram showing the connection configuration of FIG. The same configurations as those of the first and second embodiments are designated by the same reference numerals, and different configurations will be described below.

  The communication system 1b includes an OLT 20b, ONUs 30b-1 to 30b-3, an optical splitter 50, and optical fibers 40 and 41-1 to 41-3. The OLT 20b includes a duplicate stream suppressing unit 21b, and the duplicate stream suppressing unit 21b includes a distribution request reference unit 216, a selecting unit 212, a signal processing unit 213, a signal processing control unit 214b, and a storage unit 215b. Each of the ONUs 30b-1 to 30b-3 includes stream adjustment units 31b-1 to 31b-3, and each of the stream adjustment units 31b-1 to 31b-3 includes storage units 312b-1 to 312b-3. The reception processing units 313b-1 to 313b-3 are provided.

  In the duplicate stream inhibiting unit 21b, the storage unit 215b stores the PON section identifier information data 2151 and the terminal management table 2152 shown in FIG. The terminal management table 2512 has items of “terminal address”, “content identification information”, and “ONU identification information”. The terminal address given to each of the terminal devices 60-1 to 60-3 is written in the item "terminal address". Content identification information is written in the "content identification information" item. The ONU identification information of the ONUs 30a-1 to 30a-3 is written in the "ONU identification information" item.

  The distribution request reference unit 216 receives the distribution request signal or the stop request signal transmitted from the terminal devices 60-1 to 60-3 through the ONUs 30b-1 to 30b-3. The distribution request reference unit 216 includes the terminal addresses of the terminal devices 60-1 to 60-3 of the transmission source, the content identification information included in the distribution request signal or the stop request signal, and the ONUs 30a-1 to 30a-3 of the transmission source. The ONU identification information is detected. The distribution request reference unit 216 writes and stores the detected terminal address, content identification information, and ONU identification information in the terminal management table 2152 of the storage unit 215b. The distribution request reference unit 216 also outputs start instruction information including the detected terminal address, content identification information, and ONU identification information to the signal processing control unit 214b.

  When the stop request signal is referred to, the delivery request reference unit 216 deletes the record corresponding to the detected terminal address, content identification information, and ONU identification information from the terminal management table 2152 of the storage unit 215b. Further, when the distribution request reference unit 216 refers to the stop request signal, the distribution request reference unit 216 outputs the content data corresponding to the content identification information included in the stop request signal other than the terminal devices 60-1 to 60-3 that are the transmission sources of the stop request signals. When the terminal devices 60-1 to 60-3 have received the signal, the stop request signal is discarded. Further, when the suspension request signal is discarded, the distribution request reference unit 216 has the same response signal as the response signal transmitted by the server apparatus 80 to the transmission source terminal devices 60-1 to 60-3. Send a response signal. The distribution request reference unit 216 also outputs stop instruction information including the detected terminal address, content identification information, and ONU identification information to the signal processing control unit 214b.

  The signal processing control unit 214b has the following configuration in addition to the configuration of the signal processing control unit 214 of the second embodiment. That is, when the signal processing control unit 214b receives the start instruction information including the terminal address, the content identification information, and the ONU identification information from the distribution request reference unit 216, the signal processing control unit 214b includes the terminal address and the content identification information included in the start instruction information. The registration instruction information of the destination terminal address is generated. Further, the signal processing control unit 214b transmits the generated registration instruction information to the ONUs 30b-1 to 30b-3 corresponding to the ONU identification information included in the start instruction information by the control signal 102.

  When the signal processing control unit 214b receives the stop instruction information including the terminal address, the content identification information, and the ONU identification information from the distribution request reference unit 216, the signal processing control unit 214b deletes the destination terminal address including the terminal address and the content identification information. The instruction information is generated, and the generated deletion instruction information is transmitted by the control signal 102 to the ONUs 30b-1 to 30b-3 corresponding to the ONU identification information included in the stop instruction information.

  In the stream adjusting units 31b-1 to 31b-3 of the ONUs 30b-1 to 30b-3, the storage units 312b-1 to 312b-3 store the data shown in FIG. In FIG. 11, the data stored in the storage unit 312b-1 is shown as an example, and the other storage units 312b-2 and 312b-3 also store data having the same configuration.

  The storage unit 312b-1 stores the PON section identifier information data 3122-1 and the destination conversion table 3123-1. The destination conversion table 3123-1 has items of “terminal address” and “content identification information”. The terminal address given to each of the terminal devices 60-1 to 60-3 is written in the item "terminal address". Content identification information is written in the "content identification information" item.

  The reception processing units 313b-1 to 313b-3 receive the PON section identifier information from the signal processing control section 214b, and the PONs of the storage sections 312b-1 to 312b-3 corresponding to the received PON section identifier information, respectively. Write in the section identifier information data 3122-1 to 3122-3.

  Further, the reception processing units 313b-1 to 313b-3 receive registration instruction information or deletion instruction information of the destination terminal address including the terminal address and the content identification information from the signal processing control unit 214b. In addition, when the reception processing units 313b-1 to 313b-3 receive the registration instruction information, the reception processing units 313b-1 to 313b-3 read the terminal address and the content identification information from the registration instruction information and store the corresponding storage units 312b-1 to 312b-3. Destination conversion tables 3123-1 to 3123-3. Further, when receiving the deletion instruction information, the reception processing units 313b-1 to 313b-3 delete the deletion from the destination conversion tables 3123-1 to 1123-3 of the storage units 312b-1 to 312b-3 corresponding to the deletion instruction information. The record corresponding to the terminal address and the content identification information included in the instruction information is deleted.

  Further, when the reception processing units 313b-1 to 313b-3 receive the content data from the signal processing unit 213, if the content data is transmitted by broadcast distribution, the PON section identifier information data 3122-1 to 3122. The PON section identifier information written in -3 is read out. Further, when the value of the read PON section identifier information and the value of the PON section identifier of the header information included in the content data match, the reception processing units 313b-1 to 313b-3 take in the content data. ..

  Further, the reception processing units 313b-1 to 313b-3 are contents in which the fetched content data is requested by the terminal devices 60-1 to 60-3 connected to the corresponding ONU 30a-1 to ONU 30a-3. Whether or not it is data is determined based on the content identification information. In addition, when the reception processing units 313b-1 to 313b-3 determine that the content data has been requested to be distributed, the reception processing units 313b-1 to 313b-3 refer to the destination conversion tables 3123-1 to 1123-3 and refer to the destination terminals of the content data. The address is rewritten to the terminal address of the transmission source of the distribution request signal, and the content data is transmitted.

(Processing of Delivery Request Reference Section of OLT)
FIG. 12 is a flowchart showing the flow of processing performed by the distribution request reference unit 216. The distribution request reference unit 216 receives the distribution request signal or the stop request signal transmitted by the terminal devices 60-1 to 60-3 through the ONUs 30b-1 to 30b-3, and outputs the information included in the distribution request signal or the stop request signal. Reference is made (step Sb1). The distribution request reference unit 216 determines whether the request signal is a distribution request signal or a stop request signal (step Sb2). For example, when the terminal device 60-1 transmits the distribution request signal including the content # 1 as the content identification information, the distribution request reference unit 216 determines that the received request signal is the distribution request signal (step Sb2, Delivery request).

  The distribution request reference unit 216 detects the terminal address (#a), the content identification information (content # 1), and the ONU identification information (ONU # 1) of the source ONU 30b-1 from the received distribution request signal. The delivery request reference unit 216 uses the detected terminal address (#a), content identification information (content # 1), and ONU identification information (ONU # 1) as the “terminal address” of the terminal management table 2152 of the storage unit 215b. A record is generated by writing in the items of "content identification information" and "ONU identification information" (step Sb3). The delivery request reference unit 216 outputs start instruction information including the detected terminal address (#a) and content identification information (# 1) to the signal processing control unit 214b (step Sb4). The distribution request reference unit 216 transmits the received distribution request signal to the server device 80 via the relay NW 70 (step Sb5).

  On the other hand, in step Sb2, when the terminal device 60-1 transmits the stop request signal including the content identification information of the content # 1, the distribution request reference unit 216 determines that the received request signal is the stop request signal. (Step Sb2, stop request). From the received stop request signal, the distribution request reference unit 216 determines the terminal address (#a) of the terminal device 60-1, the content identification information (content # 1), and the ONU identification of the ONU 30b-1 that is the transmission source of the stop request signal. Information (ONU # 1) is detected. The delivery request reference unit 216 deletes the record corresponding to the detected terminal address (#a), content identification information (content # 1), and ONU identification information (ONU # 1) from the terminal management table 3121-1 (step Sb6). ).

  The delivery request reference unit 216 refers to the terminal management table 2152 to determine whether the content identification information (content # 1) included in the stop request signal is stored in association with another terminal address. The determination is made (step Sb7). When the terminal request reference unit 311-1 determines that the content identification information (content # 1) included in the stop request signal is not stored in association with another terminal address (step Sb7-No). , And transmits a stop request signal to the server device 80 through the relay NW 70 (step Sb10).

  On the other hand, when the distribution request reference unit 216 determines that the content identification information (content # 1) included in the stop request signal is stored in association with another terminal address (step Sb6-Yes). , The stop request signal is discarded (step Sb8). The distribution request reference unit 216 transmits the same response signal as the response signal transmitted by the server apparatus 80 in response to the stop request signal, to the terminal device 60-1 which is the transmission source of the stop request signal. Further, the distribution request reference unit 216 outputs stop instruction information for stopping the transmission of the content data of the content identification information (content # 1) to the terminal device 60-1 to the signal processing control unit 214b (step Sb9). ).

  For example, the process of step Sb9 is performed as follows. That is, in step Sb6, the distribution request reference unit 216 temporarily stores the deleted terminal address (#a), content identification information (content # 1), and ONU identification information (ONU # 1) in the internal storage area. I'll do it. In the process of step Sb9, the distribution request reference unit 216 generates the terminal address (#a) and the content identification information (content # 1) from the internal storage area when generating the stop instruction information to the signal processing control unit 214b. The ONU identification information (ONU # 1) is read. The delivery request reference unit 216 generates stop instruction information including the read terminal address (#a), content identification information (content # 1), and ONU identification information (ONU # 1). The distribution request reference unit 216 outputs the generated stop instruction information to the signal processing control unit 214b.

(Processing in the signal processing control unit of the OLT)
FIG. 13 is a flowchart showing the flow of processing performed by the signal processing control unit 214b of the OLT 20b. The signal processing control unit 214b acquires the start instruction information or the stop instruction information output by the distribution request reference unit 216 (step Sb71). The signal processing control unit 214b determines whether the instruction information is start instruction information or stop instruction information (step Sb72). When the signal processing control unit 214b determines that the instruction information is the start instruction information (step Sb72, start), it outputs the registration instruction information of the destination terminal address including the terminal address included in the start instruction information and the content identification information. It is generated (step Sb73).

  The signal processing control unit 214b transmits the generated registration instruction information to the ONUs 30b-1 to 30b-3 corresponding to the ONU identification information included in the start instruction information by the control signal 102 (step Sb74). Upon receiving the registration instruction information, the reception processing units 313b-1 to 313b-3 of the ONUs 30b-1 to 30b-3 corresponding to the ONU identification information receive the terminal address and the content identification information included in the registration instruction information. , And write to the destination conversion tables 3123-1 to 3123-3 of the storage units 312b-1 to 312b-3 corresponding to each.

  On the other hand, in step Sb72, when the signal processing control unit 214b determines that the instruction information is the stop instruction information (stop in step Sb72), the terminal address of the destination including the terminal address and the content identification information included in the stop instruction information. Address deletion instruction information is generated (step Sb75). The signal processing control unit 214b transmits the generated deletion instruction information to the ONUs 30b-1 to 30b-3 corresponding to the ONU identification information included in the stop instruction information by the control signal 102 (step Sb76). Upon receiving the deletion instruction information, the reception processing units 313b-1 to 313b-3 of the ONUs 30b-1 to 30b-3 corresponding to the ONU identification information receive the destinations of the corresponding storage units 312b-1 to 312b-3. The records corresponding to the terminal address and the content identification information included in the deletion instruction information are deleted from the conversion tables 3123-1 to 3123-3. Thereby, the reception processing units 313b-1 to 313b-3 transmit the content data of the deleted content identification information to the terminal devices 60-1 to 60-3 corresponding to the deleted terminal address. Stop.

(Processing in ONU reception processing unit)
FIG. 14 is a flowchart showing the flow of processing performed by the reception processing units 313b-1 to 313b-3 of the ONUs 30b-1 to 30b-3. The processing from step Sb51 to Sb57 is the same as the processing from step Sa51 to Sa57 performed by the reception processing units 313-1 to 313-3 of the second embodiment shown in FIG.

  Upon receiving the content data in step Sb57, the reception processing units 313b-1 to 313b-3 read the content identification information included in the captured content data. In the reception processing units 313b-1 to 313b-3, the read content identification information is stored in the destination conversion tables 3123-1 to 1123-3 of the corresponding storage units 312b-1 to 312b-3. It is determined whether or not the information matches (step Sb58). When determining that the content identification information does not match, the reception processing units 313b-1 to 313b-3 discard the captured content data (step Sb55).

  On the other hand, when the reception processing units 313b-1 to 313b-3 determine that the content identification information matches, the reception processing units 313b-1 to 313b-3 read the terminal address corresponding to the content identification information from the destination conversion tables 3123-1 to 3123-3. The reception processing units 313b-1 to 313b-3 rewrite the destination terminal address of the fetched content data with the read terminal address and transmit the content data to the terminal devices 60-1 to 60-3 (step Sb59).

  According to the configuration of the third embodiment described above, first, when the content data is not transmitted, the distribution request signal including the content identification information of the content # 1 requested by the terminal device 60-1 is transmitted. (Step Pb1 in FIG. 9), the content data of the content # 1 is transmitted from the server apparatus 80 by the broadcast distribution. Further, in all the ONUs 30a-1 to 30a-3, the reception processing units 313b-1 to 313b-3 receive the same PON section identifier information transmitted by the signal processing control unit 214b by the control signal 102, and each of the ONUs 30a-1 to 30a-3 receives it. It is written and stored in the corresponding PON section identifier information data 3122-1 to 3122-3. Therefore, when each of the reception processing units 313b-1, 313b-2, and 313b-3 performs the determination in step Sb58 of FIG. 14, the reception processing unit 313b-1 determines that the content identification information matches, The processing units 313b-2 and 313b-3 determine that the content identification information does not match. Therefore, only the reception processing unit 313b-1 performs the process of step Sb59, and the content data is transmitted only to the terminal device 60-1.

  In this state, when the distribution request signal including the content identification number of the content # 1 is transmitted from the terminal device 60-2 (step Pb2 in FIG. 9), the distribution request reference unit 216 determines, based on the distribution request signal, By the process of step Sb3 of FIG. 12, one record is newly generated in the terminal management table 2152 of the storage unit 215b. That is, the distribution request reference unit 216 includes the terminal address (#b) of the terminal device 60-2 and the content identification information (content #) in each of the items of “terminal address”, “content identification information”, and “ONU identification information”. 1), the ONU identification information (ONU # 2) of the ONU 30b-2 is written to generate a new record.

  The delivery request reference unit 216 outputs start instruction information including the terminal address (#b), the content identification information (content # 1), and the ONU identification information (ONU # 2) to the signal processing control unit 214b. The signal processing control unit 214b generates registration instruction information of the destination terminal address including the terminal address (#b), the content identification information (content # 1), and the ONU identification information (ONU # 2). The signal processing control unit 214b transmits the generated registration instruction information to the ONU 30b-2 corresponding to the ONU identification information (ONU # 2) by the control signal 102. The reception processing unit 313b-2 of the ONU 30b-2 writes the terminal address (#b) and the content identification information (content # 1) included in the registration instruction information into the destination conversion table 3123-2 of the storage unit 312b-2 and newly writes the new address. A new record.

  Based on the distribution request signal transmitted by the terminal device 60-2, the selection unit 212 of the OLT 20b determines that the content data of the same content identification information is transmitted in the process of step Sa22 of FIG. By the process of step Sa23, the selection unit 212 discards the content data transmitted from the server device 80 based on the distribution request signal transmitted by the terminal device 60-2. Since the content data of the content # 1 has already been transmitted by broadcast distribution, the selection unit 212 makes a “Yes” determination in the process of step Sa24 and ends the process. In this case, since the content data transmitted from the server device 80 based on the distribution request signal transmitted by the terminal device 60-2 is discarded, the signal processing control unit 214 processes the content data in step Sa32 of FIG. The signal processing unit 213 does not perform steps Sa41 to Sa45.

  Since the reception processing unit 313b-2 has generated new records in the destination conversion table 3123-2, that is, the record of the terminal address (#b) and the content identification information (content # 1), the processing of step Sb58 in FIG. In the processing, it is determined that the content identification information matches. The reception processing unit 313b-2 rewrites the terminal address of the destination of the fetched content data with the terminal address (#b) of the new record and transmits the content data to the terminal device 60-2. This makes it possible to avoid duplication of transmission of data having the same content and efficiently use the band in the section of the communication system 1b.

  Further, in this state, it is assumed that the terminal device 60-1 transmits a stop request signal including the content identification information of the content # 1. In step Sb7 of FIG. 12, in determining whether or not another terminal address is associated with the content identification information, the delivery request reference unit 216 determines that the content identification information (content # 1) has the terminal address (#b). ) Are associated with each other, a determination of “Yes” is made. The distribution request reference unit 216 advances the processing of steps Sb8 and Sb9, stops only the transmission of the content data to the terminal device 60-1, and continues the transmission of the content data to the terminal device 60-2. You can

(Fourth Embodiment)
FIG. 15 shows the internal configuration of the communication system 1c, the connection configuration of the communication system 1c and the terminal devices 60-1 to 60-3, the connection configuration of the communication system 1c and the relay NW70, and the relay NW70 and the server device 80 in the fourth embodiment. 3 is a block diagram showing the connection configuration of FIG. The same configurations as those of the first to third embodiments are designated by the same reference numerals, and different configurations will be described below.

  The communication system 1c includes an OLT 20c, ONUs 30b-1 to 30b-3, an optical splitter 50, and optical fibers 40 and 41-1 to 41-3. The OLT 20c includes a duplicate stream inhibiting unit 21c, and the duplicate stream inhibiting unit 21c includes a distribution request reference unit 216, a selecting unit 212, a signal processing unit 213, a signal processing control unit 214c, and a storage unit 215c.

  In the duplicate stream inhibiting unit 21c, the storage unit 215c stores the terminal management table 2152 and the identifier management table 2153 shown in FIG. The identifier management table 2153 has items of “content identification information” and “PON section identifier information”. The content identification information is written in the “content identification information” item, and “PON section identifier information”. In the item of “”, PON section identifier information is written.

  In the duplicate stream suppressing unit 21c, the signal processing control unit 214c associates different PON section identifier information with each piece of content identification information. That is, when the signal processing control unit 214c acquires the content identification information output by the selection unit 212, the signal management control unit 214c determines whether the acquired content identification information is associated with the PON section identifier information in the storage unit 215c. The determination is made by referring to the table 2153. Further, when the content identification information is not associated with the PON section identifier information, the signal processing control unit 214c newly generates PON section identifier information.

  In addition, the signal processing control unit 214c outputs the generated PON section identifier information to the signal processing unit 213 in association with the content identification information. Further, the signal processing control unit 214c refers to the terminal management table 2152, detects the ONU identification information of the ONUs 30b-1 to 30b-3 corresponding to the content identification information, and the ONU 30b-corresponding to the detected ONU identification information. The PON section identifier information corresponding to the content identification information is transmitted to 1 to 30b-3. The signal processing control unit 214c also has a configuration for performing the processing performed by the signal processing control unit 214b of the third embodiment shown in FIG.

(Processing in the signal processing control unit of the OLT)
FIG. 17 is a flowchart showing the flow of processing by the signal processing control unit 214c.
The signal processing control unit 214c performs the process of FIG. 17 instead of the process shown in steps Sa31 and Sa32 performed by the signal processing control unit 214 in the second embodiment shown in FIG.

  The signal processing control unit 214c acquires the content identification information output by the selection unit 212 in step Sa26 of FIG. 7 (step Sc31). The signal processing control unit 214c refers to the identifier management table 2153 of the storage unit 215c and determines whether the acquired content identification information is associated with the PON section identifier information (step Sc32). When the signal processing control unit 214c determines that the acquired content identification information is associated with the PON section identifier information (step Sc32-Yes), it is stored from the identifier management table 2153 in association with the content identification information. The identifier information for the PON section is read.

  On the other hand, when the signal processing control unit 214c determines that the acquired content identification information is not associated with the PON section identifier information (step Sc32-No), the signal processing control section 214c generates new PON section identifier information. The signal processing control unit 214c writes the generated PON section identifier information in the identifier management table 2153 in association with the acquired content identification information (step Sc34).

  Note that generating new PON section identifier information means that the information indicating the PON section identifier, that is, the information indicating the position of the field included in the header information is not changed and only the value of the PON section identifier is updated. It is to change with the value generated in. However, the method for generating the PON section identifier information is not limited to the method, and only the information indicating the PON section identifier may be newly generated, or the information indicating the PON section identifier and the value of the PON section identifier may be generated. Alternatively, both may be newly generated.

  The signal processing control unit 214c outputs the associated content identification information and PON section identifier information to the signal processing unit 213 (step Sc35). In step Sa42 shown in FIG. 7, the signal processing unit 213 acquires the content identification information output by the signal processing control unit 214c and the PON section identifier information. The signal processing unit 213 detects the content data corresponding to the acquired content identification information by the processing in step Sa43 shown in FIG. The signal processing unit 213 rewrites the value of the field corresponding to the information indicating the PON section identifier in the header information of the detected content data with the acquired PON section identifier by the processing in step Sa44.

  The signal processing control unit 214c refers to the terminal management table 2152 of the storage unit 215c and detects the ONU identification information corresponding to the content identification information. The signal processing control unit 214c outputs the PON section identifier information read in Step Sc33 or the PON section identifier information generated in Step Sc34 to the ONUs 30b-1 to 30b-3 corresponding to the detected ONU identification information. (Step Sc36). As a result, the reception processing units 313b-1 to 313b-3 of the ONUs 30b-1 to 30b-3 receive the PON section identifier information and store the corresponding PON section of the storage units 312b-1 to 312b-3. Write in the identifier information data 3122-1 to 3122-3. The reception processing units 313b-1 to 313b-3 determine in the processing of step Sb56 illustrated in FIG. 14 that the values of the identifiers for the PON section match, and fetch the content data being transmitted. The reception processing units 313b-1 to 313b-3 perform the determination based on the content identification information in step Sb58, convert the destination terminal address in step Sb59, and send the content data to the terminal devices 60-1 to 60-3. Send.

  With the configuration of the fourth embodiment described above, for example, as shown in FIG. 15, a distribution request signal including the content identification information of the content # 1 is transmitted from the terminal device 60-1 (step Pc1 in FIG. 15), and the content # The transmission of the content data No. 1 is started. At this time, the signal processing control unit 214c generates the PON section identifier information (# α) by the processing of step Sc34, and writes it in the identifier management table 2153 in association with the content identification information (content # 1).

  Further, by the processing of step Sc36, the signal processing control unit 214c detects the ONU identification information (ONU # 1) corresponding to the content identification information (content # 1) from the terminal management table 2152. The signal processing control unit 214c transmits the PON section identifier information (# α) by the control signal 102 to the ONU 30b-1 corresponding to the detected ONU identification information (ONU # 1). The reception processing unit 313b-1 writes the received PON section identifier information (# α) in the PON section identifier information data 3122-1 of the storage unit 312b-1.

  Next, the terminal device 60-2 transmits a distribution request signal including the content identification information of the content # 1 (step Pc2 in FIG. 15), and then transmits a distribution request signal including the content identification information of the content # 2. (Step Pc3 of FIG. 15). Furthermore, the terminal device 60-3 further transmits a distribution request signal including the content identification information of the content # 2 (step Pc4 in FIG. 15), and then transmits a distribution request signal including the content identification information of the content # 3. (Step Pc5 of FIG. 15). Similar processing is performed for these distribution request signals, and as a result, the data configurations of the storage units 312b-1 to 312b-3 of the ONUs 30b-1 to 30b-3 are shown in FIGS. 18A, 18B, and 18C. ).

  As shown in FIGS. 18A, 18B, and 18C, for the ONU 30b-1, the content data to which the PON section identifier information (# α) is added is fetched, and the destination terminal address is set to the terminal address ( It is rewritten to #a) and transmitted to the terminal device 60-1. The ONU 30b-2 fetches two types of content data to which the PON section identifier information (# α) and the PON section identifier information (# β) are added.

  Further, the ONU 30b-2 rewrites the destination terminal address of the content data of the content identification information (content # 1) and the content identification information (content # 2) with the terminal address (#b) and transmits the content data. The ONU 30b-3 takes in two types of content data to which the PON section identifier information (# β) and the PON section identifier information (# γ) are added.

  Further, the ONU 30b-3 rewrites the destination terminal address of the content data of the content identification information (content # 2) and the content identification information (content # 3) to the terminal address (#c) and transmits the content data. This makes it possible to avoid duplication of transmission of data having the same content in the section of the communication system 1c and efficiently use the band.

  Further, since different PON section identifier information is associated with each piece of content identification information, that is, with each piece of different content data, the load of content data reception processing in the ONUs 30b-1 to 30b-3 is reduced, and the content data distribution processing is performed. Can be easily controlled. For example, if a distributor or the like operating the server device 80 does not want to view particular content data, the content identification information corresponding to the content data should be set such that the PON section identifier information is not assigned. Is possible.

  Further, for example, in the case where the content data of the specific content identification information is not transmitted to the specific ONUs 30b-1 to 30b-3, for example, the ONU 30b-1, the identification is performed in the process of step Sc36 of FIG. When the ONU identification information of the ONU 30b-1 is detected, the PON section identifier information may not be transmitted to the ONU 30b-1 of the ONU identification information.

(Fifth Embodiment)
FIG. 19 shows the internal configuration of the communication system 1d, the connection configuration of the communication system 1d and the terminal devices 60-1 to 60-3, the connection configuration of the communication system 1d and the relay NW 70, and the relay NW 70 and the server device 80 in the fifth embodiment. 3 is a block diagram showing the connection configuration of FIG. The same configurations as those of the first to fourth embodiments are designated by the same reference numerals, and different configurations will be described below.

  The communication system 1d includes an OLT 20d, ONUs 30b-1 to 30b-3, an optical splitter 50, and optical fibers 40, 41-1 to 41-3. The OLT 20d includes a duplicate stream suppressing unit 21d, and the duplicate stream suppressing unit 21d includes a distribution request reference unit 216, a selecting unit 212, a signal processing unit 213, a signal processing control unit 214d, and a storage unit 215d.

  In the duplicate stream suppressing unit 21d, the storage unit 215d stores the terminal management table 2152, the identifier management table 2153, and the group designation table 2154 shown in FIG. The group designation table 2154 has items of “content identification information” and “group number”, the content identification information is written in the item of “content identification information”, and the item of “group number” is A number indicating a group associated with the content identification information is written. For example, in the example of FIG. 20, the content # 1 belongs to the group with the group number “1”, and the content # 2 and the content # 3 belong to the group with the group number “2”.

  The data written in the "content identification information" and "group number" items of the group designation table 2154 is data written in advance by the operator of the communication system 1d. If the group is not set for the content data, no record is provided in the group designation table 2154, that is, the content identification information and the group number data are not written.

  In the duplicate stream suppression unit 21d, the signal processing control unit 214d associates different PON section identifier information with each group of content identification information. That is, when the signal processing control unit 214d acquires the content identification information output by the selection unit 212, the signal management control unit 214d determines whether the acquired content identification information is associated with the PON section identifier information in the storage unit 215d. The determination is made by referring to the table 2153. Further, when the content identification information is not associated with the PON section identifier information, the signal processing control unit 214d determines whether or not other content identification information belonging to the same group exists with respect to the content identification information. It is determined by referring to the group designation table 2154 of the storage unit 215d.

  In addition, when other content identification information belonging to the same group exists, the signal processing control unit 214d determines whether or not the PON section identifier information is associated with the other content identification information, the identifier of the storage unit 215d. The determination is made by referring to the management table 2153. Further, the signal processing control unit 214d newly generates PON section identifier information when other content identification information belonging to the same group is not associated with the PON section identifier information. Further, the signal processing control unit 214c corresponds to the generated PON section identifier information or the content identification information output by the selection section 212 from the PON section identifier information associated with the content identification information belonging to the same group. It attaches and outputs to the signal processing part 213.

  Further, the signal processing control unit 214c refers to the terminal management table 2152, detects the ONU identification information of the ONUs 30b-1 to 30b-3 corresponding to the content identification information, and the ONU 30b-corresponding to the detected ONU identification information. The PON section identifier information corresponding to the content identification information is transmitted to 1 to 30b-3. Further, the signal processing control unit 214d also has a configuration for performing the processing performed by the signal processing control unit 214b of the third embodiment shown in FIG.

(Processing in the signal processing control unit of the OLT)
FIG. 21 is a flowchart showing the flow of processing by the signal processing control unit 214d.
The signal processing control unit 214d performs the process in FIG. 21 in place of the process shown in steps Sa31 and Sa32 performed by the signal processing control unit 214 in the second embodiment shown in FIG.

  The signal processing control unit 214d acquires the content identification information output by the selection unit 212 in step Sa26 of FIG. 7 (step Sd31). The signal processing control unit 214d refers to the identifier management table 2153 of the storage unit 215d and determines whether the acquired content identification information is associated with the PON section identifier information (step Sd32). When the signal processing control unit 214d determines that the acquired content identification information is associated with the PON section identifier information (step Sd32-Yes), it is associated with the content identification information from the identifier management table 2153. The identifier information for the PON section is read (step Sd33).

  On the other hand, if the signal processing control unit 214d determines that the acquired content identification information is not associated with the PON section identifier information (step Sd32-No), the signal processing control unit 214d refers to the group designation table 2154 and refers to the content identification information. It is determined whether or not the group number is associated with. (Step Sd34). When the signal processing control unit 214d determines that the group designation table 2154 is not associated with the group number in association with the content identification information (step Sd34-No), it generates new PON section identifier information. .. The signal processing control unit 214d writes the generated PON section identifier information in association with the content identification information in the identifier management table 2153 (step Sd36).

  On the other hand, when the signal processing control unit 214d determines that the group designation table 2154 is associated with the group number in association with the content identification information (step Sd34-Yes), another signal having the same group number is displayed. The content identification information is read from the group designation table 2154. The signal processing control unit 214d determines whether or not the PON section identifier information is associated with other content identification information having the same group number read from the group designation table 2154, by referring to the identifier management table 2153. (Step Sd35).

  When the signal processing control unit 214d determines that the other PON section identifier information having the same group number is not associated with the PON section identifier information (step Sd35-No), it generates new PON section identifier information. To do. The signal processing control unit 214d writes the generated PON section identifier information in association with the content identification information in the identifier management table 2153 (step Sd36). Although the group number is defined in the group designation table 2154, if there is no other content identification information corresponding to the same group number, another content identification having the same group number is performed in the process of step Sd35. It is determined that the PON section identifier information is not associated with the information (step Sd35-No).

  On the other hand, when the signal processing control unit 214d determines that the PON section identifier information is associated with other content identification information having the same group number (step Sd35-Yes), the other information is identified from the identifier management table 2153. The PON section identifier information associated with the content identification information is read. The signal processing control unit 214d writes the read PON section identifier information in the identifier management table 2153 in association with the content identification information output by the selection unit 212 (step Sd37).

  The signal processing control unit 214d outputs the associated content identification information and PON section identifier information to the signal processing unit 213 (step Sd38). In step Sa42 shown in FIG. 7, the signal processing unit 213 acquires the content identification information output by the signal processing control unit 214d and the PON section identifier information. The signal processing unit 213 detects the content data including the content identification information by the processing in step Sa43. The signal processing unit 213 rewrites the value of the field corresponding to the information indicating the PON section identifier of the header information of the detected content data to the value of the PON section identifier by the processing of step Sa44.

  The signal processing control unit 214d refers to the terminal management table 2152 of the storage unit 215d and detects the ONU identification information corresponding to the content identification information. The signal processing control unit 214d provides the ONUs 30b-1 to 30b-3 corresponding to the ONU identification information with the PON section identifier information read in step Sd33, or the PON section identifier information generated in step Sd36, or step Sd37. Then, the PON section identifier information associated with the other content identification information having the same group number read from the identifier management table 2153 is output (step Sd39).

  As a result, the reception processing units 313b-1 to 313b-3 of the ONUs 30b-1 to 30b-3 receive the PON section identifier information and store the corresponding PON section of the storage units 312b-1 to 312b-3. Write in the identifier information data 3122-1 to 3122-3. The reception processing units 313b-1 to 313b-3 determine in the processing of step Sb56 illustrated in FIG. 14 that the values of the identifiers for the PON section match, and fetch the received content data. The reception processing units 313b-1 to 313b-3 perform the determination based on the content identification information in step Sb58, convert the destination terminal address in step Sb59, and send the content data to the terminal devices 60-1 to 60-3. Send.

  With the configuration of the fifth embodiment described above, for example, the same group number “2” is associated in advance with content # 2 and content # 3 as shown in the group designation table 2154 of FIG. First, similarly to step Pc1 and step Pc2 of the fourth embodiment, the processes of step Pd1 and step Pd2 shown in FIG. 19 are performed, and the content data whose content identification information is content # 1 is distributed by the server device. It is assumed that the data is transmitted from 80 to the terminal device 60-1 and the terminal device 60-2.

  As shown in FIG. 19, a distribution request signal including the content identification information of the content # 2 is transmitted from the terminal device 60-2 (step Pd3 in FIG. 19), and the transmission of the content data of the content # 2 is started. The content # 3 has the same group number as the content # 2, but at this point in time, the distribution request for the content # 3 has not been made. Therefore, in the identifier management table 2153, the content # 3 has the PON. The section identifier information is not associated. Therefore, by the process of step Sd36, the signal processing control unit 214d newly generates PON section identifier information (# β) and writes it in the identifier management table 2153 in association with the content identification information (content # 2).

  Further, by the processing of step Sd39, the signal processing control unit 214d detects the ONU identification information (ONU # 2) corresponding to the content identification information (content # 2) from the terminal management table 2152. The signal processing control unit 214d transmits the PON section identifier information (# β) by the control signal 102 to the ONU 30b-2 corresponding to the ONU identification information (ONU # 2). The reception processing unit 313b-2 writes the received PON section identifier information (# β) in the PON section identifier information data 3122-2 of the storage unit 312b-2.

  After that, when the terminal device 60-3 transmits a distribution request signal including the content # 2 as the content identification information (step Pd4 in FIG. 19), the content data of the content # 2 has already been distributed by the signal processing unit 213 by the broadcast. The content data corresponding to the distribution request signal is discarded because it has been transmitted. The signal processing control unit 214d transmits the PON section identifier information (# β) already associated with the content # 2 to the reception processing unit 313b-3 of the ONU 30b-3 by the process of step Sd39. Accordingly, the reception processing unit 313b-3 takes in the content data to which the PON section identifier information (# β) is added, rewrites the destination terminal address, and transmits it to the terminal device 60-3.

  After that, the terminal device 60-3 further transmits a distribution request signal including the content # 3 as content identification information (step Pd5 in FIG. 19). For the content # 3, the content # 2 having the same group number “2” is defined in the group designation table 2154. Further, in the identifier management table 2153, the content # 2 is already associated with the PON section identifier information (# β). Therefore, by the process of step Sd37, the signal processing control unit 214d reads the PON section identifier information (# β) corresponding to the content # 2 from the identifier management table 2153, and the read PON section identifier information (# β). Is associated with the content # 3 and written in the identifier management table 2153. Through the processing in step Sd38, the signal processing control unit 214d outputs the content identification information (content # 3) and the PON section identifier information (# β) to the signal processing unit 213.

  The signal processing unit 213, based on the PON section identifier information (# β), the value of the field corresponding to the information indicating the PON section identifier of the header information of the content data corresponding to the content identification information (content # 3). Is rewritten with the value of the identifier for the PON section and the content data is transmitted. As a result, the value of the PON section identifier is added to the field in the header information indicated by the same PON section identifier in the content data of both content # 2 and content # 3.

  This makes it possible to avoid duplication of transmission of data having the same content in the section of the communication system 1d and efficiently use the band. Further, since different PON section identifier information is associated with each group of content identification information, the load of content data reception processing in the ONUs 30b-1 to 30b-3 is reduced, and the distribution processing of content data is controlled. Can be made easier. For example, when a distributor or the like operating the server device 80 does not want to view the content data of a specific group, it is possible to set such that the PON section identifier information is not assigned to the content identification information belonging to the group. Become.

(Another configuration example of the fifth embodiment)
For example, in the communication system 1d of the fifth embodiment, the same group number (for example, “1” in FIG. 22) may be associated with all content identification information in the group designation table 2154 of the storage unit 215d. Good. In this case, the same PON section identifier information is associated with all content data. That is, as shown in FIG. 23, since the operation is performed with one PON section identifier information in the section of the communication system 1d, the content data is transmitted to all the ONUs 30b-1 to 30b-3 by a simple setting. can do.

(Sixth Embodiment)
FIG. 24 is an internal configuration of the communication system 1e, a connection configuration between the communication system 1e and the terminal devices 60-1 to 60-3, a connection configuration between the communication system 1e and the relay NW70, and a relay NW70 and the server device 80 in the sixth embodiment. 3 is a block diagram showing the connection configuration of FIG. The same configurations as those of the first to fifth embodiments are designated by the same reference numerals, and different configurations will be described below.

  The communication system 1e includes an OLT 20e, ONUs 30b-1 to 30b-3, an optical splitter 50, and optical fibers 40 and 41-1 to 41-3. The OLT 20e includes a duplicate stream inhibiting unit 21e, and the duplicate stream inhibiting unit 21e includes a distribution request reference unit 216e, a selecting unit 212e, a signal processing unit 213, a signal processing control unit 214b, and a storage unit 215b.

  In the duplicate stream suppression unit 21e, the distribution request reference unit 216e receives the distribution request signal or the stop request signal transmitted by the terminal devices 60-1 to 60-3 through the ONUs 30b-1 to 30b-3, and the distribution request signal. Or, refer to the information included in the stop request signal. When the received signal is a distribution request signal, the distribution request reference unit 216e determines whether the content data corresponding to the content identification information included in the distribution request signal has already been transmitted through the selection unit 212e and the signal processing unit 213. To determine. Further, the distribution request reference unit 216e discards the distribution request signal when the content data corresponding to the content identification information included in the distribution request signal has already been transmitted through the selection unit 212e and the signal processing unit 213.

  In the duplicate stream suppression unit 21e, the selection unit 212e receives inquiry request information inquiring from the distribution request reference unit 216e whether or not content data corresponding to the content identification information is being transmitted. Upon receiving the inquiry request information, the selection unit 212e detects the transmission state of the content data with respect to the content identification information, and indicates “not transmitted” indicating that the content data is not transmitted, or is in the transmitting state. "Sending" indicating that there is is output as a response. Further, when the selection unit 212e receives the content data from the server device 80, the selection unit 212e signals the received content data without determining the transmission state of the content data having the same content as in the selection unit 212 of the second embodiment. The content identification information of the content data is output to the processing unit 213, and is output to the signal processing control unit 214b.

(Processing in OLT Delivery Request Reference Section)
FIG. 25 is a flowchart showing the flow of processing by the distribution request reference unit 216e. The distribution request reference unit 216e receives the distribution request signal or the stop request signal transmitted by the terminal devices 60-1 to 60-3 through the ONUs 30b-1 to 30b-3, and outputs the information included in the distribution request signal or the stop request signal. Reference is made (step Se1). The distribution request reference unit 216e determines whether the request signal is a distribution request signal or a stop request signal (step Se2).

  When the distribution request reference unit 216e determines that the received request signal is a distribution request signal (step Sb2, distribution request), the distribution request signal indicates the terminal address, the content identification information, and the ONU identification information of the source ONU 30b-1. To detect. The delivery request reference unit 216 writes the detected terminal address, content identification information, and ONU identification information in the items of “terminal address”, “content identification information”, and “ONU identification information” in the terminal management table 2152 of the storage unit 215b. To generate a record (step Se3).

  The delivery request reference unit 216e outputs start instruction information including the detected terminal address and content identification information to the signal processing control unit 214b (step Se4). The distribution request reference unit 216e outputs inquiry request information including the content identification information to the selection unit 212e in order to detect whether or not the content data corresponding to the content identification information is transmitted to the selection unit 212. When the selection unit 212e receives the inquiry request information and is transmitting the content data corresponding to the content identification information included in the inquiry request information, the selection unit 212e responds with "transmitting". On the other hand, when the content data corresponding to the content identification information included in the inquiry request information has not been transmitted, the selection unit 212e responds with "not transmitted" (step Se5). The delivery request reference unit 216e determines whether the response is "transmitting" or "not transmitted" (step Se6).

  When the distribution request reference unit 216e determines that the response is “untransmitted” (step Se6, untransmitted), the distribution request reference unit 216e transmits the distribution request signal to the server device 80 through the relay NW 70 and ends the process (step Se7). On the other hand, when the distribution request reference unit 216e determines that the response is "transmitting", the distribution request reference unit 216e discards the distribution request signal, and the terminal device 60-1 to 60-3 that is the transmission source of the distribution request signal transmits the server device 80. Transmits the same response signal as the response signal transmitted to the distribution request signal and ends the process (step Se8).

  On the other hand, in step Se2, when the distribution request reference unit 216e determines that the request signal is the stop request signal (step Se2, stop request), the processes of steps Se9 to Se13 are performed. Is the same process as the process of steps Sb6 to Sb10 shown in FIG. 12 performed by the distribution request reference unit 216 of the third embodiment.

(Processing in the selection unit of OLT)
FIG. 26 is a flowchart showing a processing flow of the selection unit 212e. The selection unit 212e performs the processes of the following steps Se21 to Se23 instead of the processes of the steps Sa21 to Sa26 shown in FIG. 7 performed by the selection unit 212 of the second embodiment. The selection unit 212e receives the content data from the server device 80 (step Se21). The selection unit 212e outputs the received content data to the signal processing unit 213 (step Se22). The signal processing unit 213 acquires the content data output by the selection unit 212e in the process of step Sa41 shown in FIG. The selection unit 212e outputs the content identification information of the content data to the signal processing control unit 214b (step Se23). The signal processing control unit 214b acquires the content identification information output by the selection unit 212e in step Sa32 shown in FIG.

  With the configuration of the sixth embodiment described above, the distribution request reference unit 216e determines whether the content data corresponding to the content identification information included in the distribution request signal has already been transmitted, and if it has already been transmitted, the distribution is performed. Discard the request signal. This makes it possible to avoid redundant transmission of data having the same content and efficiently use the band in the section of the communication system 1e. Further, when the content data corresponding to the content identification information included in the distribution request signal has already been transmitted, the distribution request signal is discarded in the OLT 20e without transmitting the distribution request signal to the server device 80. It is possible to reduce the bandwidth and the load on the server device 80.

  In the second to sixth embodiments, the destination MAC address of the MAC address and the destination IP address field of the IP address are applied as the PON section identifier. However, the configuration of the present invention is not limited to this embodiment. Not limited to Any information may be used as long as it is identifier information that can identify the content data. For example, a new field is added to the content data, and the newly added field is used as the value of the PON section identifier. It may be a field to write.

  Further, in the above second to sixth embodiments, a field other than the destination MAC address of the MAC address or the destination IP address of the IP address in the header information may be used as the PON section identifier. However, when the fields other than the destination MAC address of the MAC address and the destination IP address of the IP address are used as the PON section identifier, the content data can be reproduced normally in the terminal devices 60-1 to 60-3 as follows. Need to be processed. That is, in the reception processing units 313-1 to 313-3 and 313b-1 to 313b-3, the original value before being rewritten to the value of the PON section identifier is stored in advance, or the signal processing control units 214 and 214b. , 214c, 214d to receive the original values. Then, before transmitting the content data to the terminal devices 60-1 to 60-3, the reception processing units 313-1 to 313-3 and 313b-1 to 313b-3 write back the original values and then the content data. Need to send.

  Further, in the configurations of the second to sixth embodiments, all the content data requested to be distributed from the terminal devices 60-1 to 60-3 are processed by the signal processing unit 213 in step Sa45 of FIG. , And the content data to which the unicast logical link ID is added does not exist. However, the configuration of the present invention is not limited to this embodiment. For example, when the content data having the same content identification information is not transmitted, that is, when the content data is transmitted for the first time, the signal processing unit 213 adds the unicast logical link ID to the content. The data may be transmitted. At this time, when a distribution request for the content data corresponding to the same content identification information is newly made, in the configurations of the second to sixth embodiments, the logical link ID for broadcast is added to the content data already transmitted. As a result, the transmission is switched to the broadcast distribution. Therefore, even with the above configuration, it is possible to obtain the same effect as that of the configurations of the second to sixth embodiments in which the redundant transmission of the data of the same content is avoided and the band is efficiently used.

  Further, as described above, when the transmission to which the unicast logical link ID is added is changed to the transmission to which the broadcast logical link ID is added, the signal processing unit 213 is provided with a means such as a buffer. Therefore, it is necessary to avoid the interruption of the content data. Further, not only when the logical link ID is changed, but also when the information indicated by the PON section identifier or the value of the PON section identifier is changed, the interruption of the content data is avoided by means such as providing a buffer. You need to keep it.

  In the second to sixth embodiments described above, when the distribution request signal is transmitted, the content data being transmitted is left and the content data that has been transmitted based on the distribution request signal is discarded. However, the configuration of the present invention is not limited to this embodiment. The content data being transmitted may be discarded, and the content data that has started to be transmitted based on the distribution request signal may be transmitted by broadcast distribution. In this case, when discarding the content data, the sequence number at which discarding is started is detected in advance, and in the content data to be newly transmitted by broadcast transmission, the packet having the sequence number at which discarding is started is transmitted, The terminal devices 60-1 to 60-3 that have received the discarded content data can play the content data without interruption. Further, at this time, a means for avoiding a momentary interruption of the content data may be further provided by means such as providing a buffer.

  In addition, in the second, third, and sixth embodiments described above, the same PON section identifier information is applied to all the ONUs 30a-1 to 30a-3, 30b-1 to 30b-3. However, the configuration of the present invention is not limited to this embodiment. For example, different PON section identifier information may be applied to each of the ONUs 30a-1 to 30a-3, 30b-1 to 30b-3 of the second, third, and sixth embodiments, Different PON section identifier information may be applied depending on the combination of the content identification information and the ONUs 30a-1 to 30a-3, 30b-1 to 30b-3.

  In addition, in the second to sixth embodiments, when the reception processing units 313-1 to 313-3 and 313b-1 to 313b-3 transmit content data to the terminal devices 60-1 to 60-3. , The destination terminal address of the content data is rewritten to the terminal address corresponding to the content identification information, but if the destination terminal address of the content data matches the terminal address corresponding to the content identification information, it is rewritten. May not be performed.

  Further, in the configurations of the above-described first to fifth embodiments, when determining whether the content data is the same, the determination is performed only based on whether the content identification information is the same. The configuration of the invention is not limited to the embodiment. For example, if the content identification information is the same and the VIDs assigned to the content data are different, it may be determined that the content data are the same. Further, when the content identification information is the same and the terminal address written in the destination of the content data is different, the content data may be determined to be the same. When both of these two conditions are satisfied, that is, the content identification information is the same, the VIDs assigned to the content data are different, and the terminal address written in the destination of the content data is If they are different, it may be determined that the content data are the same.

  Further, in the second to sixth embodiments described above, the process of deleting a record based on the stop request signal, for example, steps Sa6 and Sa7 shown in FIG. 6, step Sb6 shown in FIG. 12, step Se9 shown in FIG. The process shown is for determining whether or not another terminal address is associated with the content identification information to be deleted, that is, step Sa8 shown in FIG. 6, step Sb7 shown in FIG. 12, step Se10 shown in FIG. It may be performed after the determination process of. However, when the order of processing is changed, it is necessary to exclude the record to be deleted from the judgment target in the judgment processing.

  Further, in the second to sixth embodiments described above, even if the stop request signal is not transmitted, a response is sent from the destination terminal devices 60-1 to 60-3 to the content data distribution process for a certain period of time. If not, the record may be deleted from the terminal management tables 3121-1 to 3121-3 and the terminal management table 2152 by timing out.

  In addition, in the above-described first to sixth embodiments, the redundant stream suppressing units 21, 21a, 21b, 21c, 21d, 21e are provided in an external device other than the OLT 20, 20a, 20b, 20c, 20d, 20e. Good. Further, the stream adjusting units 31-1 to 31-3, 31a-1 to 31a-3, 31b-1 to 31b-3 are connected to the ONUs 30-1 to 30-3, 30a-1 to 30a-3, 30b-1 to 30b. It may be provided in an external device other than -3.

  In the first to sixth embodiments, the unicast logical link ID is applied as the ONU identification information, but the ONUs 30-1 to 30-3, 30a-1 to 30a-3, 30b- are used. Any information may be used as long as it is identification information that can identify 1 to 30b-3. Further, among the communication devices such as routers provided in the relay NW 70, the VID is applied as the information corresponding to the ONU identification information given by the communication device transmitting the data to the OLT 20, but the ONU identification information is used. Any information may be used as long as the information corresponds to.

Further, in the above-described first to sixth embodiments, the number of branches of the optical splitter 50 may be any number as long as it is a plurality of branches, and is not limited to three branches.
Further, in the above-described first to sixth embodiments, the server device 80 is not limited to one, and a plurality of server devices 80 may be connected to the relay NW 70, and different server devices 80 have the same content. The content data may be transmitted.

  Further, the fourth and fifth embodiments described above are based on the configuration of the third embodiment, but the configuration of the present invention is not limited to this embodiment. For example, in the configurations of the second and sixth embodiments, the configuration of the fourth embodiment in which different pieces of content identification information are associated with different PON section identifier information, and the different pieces of content identification information for different PON section identifier information are used. The configuration of the corresponding fifth embodiment may be applied. Further, the configuration of the second embodiment may be applied to the configuration of the sixth embodiment so that the ONUs 30b-1 to 30b-3 detect the terminal address and the content identification information.

  In addition, in the above-described first to sixth embodiments, the content data transmitted by the server device 80 is content data including real-time video and audio such as live distribution, but it may be broadcast stream data. For example, it may be in any format and may be data composed of data other than video and audio.

  The OLTs 20, 20a, 20b, 20c, 20d, 20e and ONUs 30-1 to 30-3, 30a-1 to 30a-3, 30b-1 to 30b-3 in the above-described embodiments may be realized by a computer. .. In that case, the program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in this recording medium may be read by a computer system and executed. The “computer system” mentioned here includes an OS and hardware such as peripheral devices. Further, the “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in a computer system. Further, the "computer-readable recording medium" means to hold a program dynamically for a short time like a communication line when transmitting the program through a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system that serves as a server or a client in that case may hold a program for a certain period of time. Further, the program may be for realizing some of the functions described above, or may be one that can realize the functions described above in combination with a program already recorded in the computer system, It may be realized using a programmable logic device such as FPGA (Field Programmable Gate Array).

  Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes a design and the like within a range not departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Communication system, 20 ... OLT, 21 ... Duplication stream suppression part, 30-1, 30-2, 30-3 ... ONU, 31-1 to 31-3 ... Stream adjustment part, 40, 41-1 to 41- 3 ... Optical fiber, 50 ... Optical splitter, 60-1 to 60-3 ... Terminal device, 70 ... Relay NW, 80 ... Server device

Claims (7)

A plurality of subscriber-side optical line terminal devices to which the terminal device is connected, and a station-side optical line terminal device are connected by a multiplex distributor,
The station side optical line terminal device,
When a terminal device connected to any one of the subscriber side optical line terminal devices transmits a distribution request signal requesting to receive data from the outside, data having the same content as the data is transferred to another terminal device. When it is being transmitted to, the data corresponding to the distribution request signal is not transmitted, and the data being transmitted is transmitted to the multiplex distributor as broadcast distribution,
The subscriber-side optical line terminator to which the terminal device of the transmission source of the distribution request signal is connected,
When receiving the data transmitted by broadcasting from the multiple distributor, met communication system transmits rewrites the destination of the data received to the terminal address of the source of the terminal apparatus of the distribution request signal hand,
The subscriber side optical line terminal device,
Data identification information that uniquely identifies the data included in the distribution request signal, and a terminal request reference unit that detects a terminal address of the terminal device,
When the station side optical line terminal receives data to be transmitted by broadcast distribution, the data identification information of the received data matches the data identification information detected by the terminal request reference unit, and the data A reception processing unit that rewrites the destination of the data to the terminal address corresponding to the data identification information and transmits the data to the terminal device,
Equipped with
The station side optical line terminal device,
When the data that is being transmitted and has the same data identification information as the data identification information included in the distribution request signal is transmitted by broadcast distribution, the identifier information that can be uniquely identified is the data identification information. And a signal processing control unit that transmits the identifier information corresponding to the data identification information to the subscriber-side optical line termination device connected to the terminal device that is the transmission source of the distribution request signal,
When the identifier information is associated with the data identification information by the signal processing control unit, a signal processing unit that adds the identifier information to the data and transmits by broadcast distribution,
Equipped with
The reception processing unit of the subscriber side optical line terminal device,
When the station side optical line terminal receives the data to be transmitted by the broadcast distribution, when the identifier information received from the signal processing control unit is not added to the received data, the data is discarded, When the identifier information is added, the data is captured, and when the data identification information of the captured data matches the data identification information included in the distribution request signal, the destination of the data is identified as the data identification. A communication system in which the terminal address corresponding to information is rewritten and the data is transmitted to the terminal device. A plurality of subscriber-side optical line terminal devices to which the terminal device is connected, and a station-side optical line terminal device are connected by a multiplex distributor,
The station side optical line terminal device,
When a terminal device connected to any one of the subscriber side optical line terminal devices transmits a distribution request signal requesting to receive data from the outside, data having the same content as the data is transferred to another terminal device. When it is being transmitted to, the data corresponding to the distribution request signal is not transmitted, and the data being transmitted is transmitted to the multiplex distributor as broadcast distribution,
The subscriber-side optical line terminator to which the terminal device of the transmission source of the distribution request signal is connected,
When receiving the data transmitted by broadcasting from the multiple distributor, met communication system transmits rewrites the destination of the data received to the terminal address of the source of the terminal apparatus of the distribution request signal hand,
The station side optical line terminal device,
Data identification information that uniquely identifies the data included in the distribution request signal, a terminal address of the terminal device, and termination device identification information that uniquely identifies the subscriber-side optical line termination device to which the terminal device is connected. And a delivery request reference unit for detecting
The subscriber-side optical line terminator corresponding to the terminator identification information detected by the distribution request reference unit,
The data identification information detected by the distribution request reference unit and the terminal address of the terminal device are received from the station side optical line terminating device, and the data transmitted by the station side optical line terminating device by broadcast delivery is received. In this case, when the data identification information of the received data matches the data identification information detected by the distribution request reference unit, the destination of the data is rewritten to the terminal address corresponding to the data identification information, and the data is rewritten. A reception processing unit for transmitting to the terminal device,
The station side optical line terminal device,
When the data that is being transmitted and has the same data identification information as the data identification information included in the distribution request signal is transmitted by broadcast distribution, the identifier information that can be uniquely identified is the data identification information. And a signal processing control unit that transmits the identifier information corresponding to the data identification information to the subscriber-side optical line termination device connected to the terminal device that is the transmission source of the distribution request signal,
When the identifier information is associated with the data identification information by the signal processing control unit, a signal processing unit that adds the identifier information to the data and transmits the data by broadcast distribution,
Further equipped with,
The reception processing unit of the subscriber side optical line terminal device,
When the station side optical line terminal receives data to be transmitted by the broadcast distribution, when the identifier information received from the signal processing control unit is not added to the received data, the data is discarded, When the identifier information is added, the data is captured, and when the data identification information of the captured data matches the data identification information included in the distribution request signal, the destination of the data is identified as the data identification. A communication system in which the terminal address corresponding to information is rewritten and the data is transmitted to the terminal device. The station side optical line terminal device,
When the data is received from the outside based on the distribution request signal, it is determined whether or not the data having the same content as the received data is being transmitted to the other terminal device, and the data is transmitted. when it is determined to be in, or discarding the data received from the outside based on the distribution request signal, or, discarding the distribution request signal, the communication system according to claim 1 or 2. Either the station side optical line terminator or the subscriber side optical line terminator,
When the terminal device transmits a stop request signal requesting a stop of transmission for the data being transmitted by the broadcast distribution, when the data is being transmitted to the other terminal device, The communication system according to claim 1, wherein the stop request signal is discarded, and a response signal to the stop request signal is transmitted to the terminal device that is the transmission source of the stop request signal. The signal processing control unit,
When the data identification information included in the distribution request signal and the data identification information included in the data being transmitted by the broadcast distribution belong to the same predetermined group, the data being transmitted by the broadcast distribution is The subscriber-side optical line terminal to which the identifier information corresponding to the included data identification information is associated with the data identification information included in the distribution request signal, and which is connected to the terminal device that is the transmission source of the distribution request signal. The communication system according to claim 1, wherein the identifier information corresponding to the data identification information included in the distribution request signal is transmitted to a device. A plurality of subscriber-side optical line terminal devices to which the terminal device is connected, and a station-side optical line terminal device are connected by a multiplex distributor ,
The station side optical line terminal device,
One of said terminals being connected to the subscriber optical network unit apparatus, when transmitting a distribution request signal for requesting to receive data from the outside, said data of the data having the same content of other When the data is being transmitted to the terminal device, the data corresponding to the distribution request signal is not transmitted, and the data being transmitted is transmitted to the multiplex distributor as broadcast distribution,
The subscriber-side optical line terminator to which the terminal device of the transmission source of the distribution request signal is connected,
When receiving the data transmitted by the broadcast distribution from the multiplex distributor, the communication method by the communication system in which the destination of the received data is rewritten to the terminal address of the terminal device which is the transmission source of the distribution request signal and is transmitted. And
The subscriber side optical line terminal device,
Data identification information for uniquely identifying the data included in the distribution request signal, and a terminal request reference step of detecting a terminal address of the terminal device,
When the station side optical line terminal receives data to be transmitted by broadcast distribution, the data identification information of the received data matches the data identification information detected in the terminal request reference step, Receiving step of rewriting the destination of the above to the terminal address corresponding to the data identification information and transmitting the data to the terminal device,
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The station side optical line terminal device,
When the data that is being transmitted and has the same data identification information as the data identification information included in the distribution request signal is transmitted by broadcast distribution, the identifier information that can be uniquely identified is the data identification information. And a signal processing control step of transmitting the identifier information corresponding to the data identification information to the subscriber-side optical line termination device connected to the terminal device of the transmission source of the distribution request signal,
If the identifier information is associated with the data identification information in the signal processing control step, a signal processing step of adding the identifier information to the data and transmitting by broadcast distribution,
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In the reception processing step, the subscriber side optical line terminal device,
When the station side optical line terminal receives the data to be transmitted by the broadcast distribution, the data is discarded when the identifier information transmitted in the signal processing control step is not added to the received data. When the identifier information is added, the data is captured, and when the data identification information of the captured data matches the data identification information included in the distribution request signal, the destination of the data is the data. A communication method in which the terminal address corresponding to identification information is rewritten and the data is transmitted to the terminal device. A plurality of subscriber-side optical line terminal devices to which the terminal device is connected, and a station-side optical line terminal device are connected by a multiplex distributor ,
The station side optical line terminal device,
One of said terminals being connected to the subscriber optical network unit apparatus, when transmitting a distribution request signal for requesting to receive data from the outside, said data of the data having the same content of other When the data is being transmitted to the terminal device, the data corresponding to the distribution request signal is not transmitted, and the data being transmitted is transmitted to the multiplex distributor as broadcast distribution,
The subscriber-side optical line terminator to which the terminal device of the transmission source of the distribution request signal is connected,
When receiving the data transmitted by the broadcast distribution from the multiplex distributor, the communication method by the communication system in which the destination of the received data is rewritten to the terminal address of the terminal device which is the transmission source of the distribution request signal and is transmitted. And
The station side optical line terminal device,
Data identification information that uniquely identifies the data included in the distribution request signal, a terminal address of the terminal device, and termination device identification information that uniquely identifies the subscriber-side optical line termination device connected to the terminal device. Perform the delivery request reference step to detect and
The subscriber-side optical line terminator corresponding to the terminator identification information detected in the distribution request reference step,
The data identification information and the terminal address of the terminal device detected in the distribution request reference step are received from the station side optical line terminating device, and the data transmitted by the station side optical line terminating device by broadcast delivery is received. In this case, when the data identification information of the received data matches the data identification information detected in the distribution request reference step, the destination of the data is rewritten to the terminal address corresponding to the data identification information, and Performing a reception processing step of transmitting data to the terminal device,
The station side optical line terminal device,
When the data that is being transmitted and has the same data identification information as the data identification information included in the distribution request signal is transmitted by broadcast distribution, the identifier information that can be uniquely identified is the data identification information. And a signal processing control step of transmitting the identifier information corresponding to the data identification information to the subscriber-side optical line termination device connected to the terminal device of the transmission source of the distribution request signal,
If the identifier information is associated with the data identification information in the signal processing control step, a signal processing step of adding the identifier information to the data and transmitting by broadcast distribution,
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In the reception processing step, the subscriber side optical line terminal device,
When the station side optical line terminal receives the data to be transmitted by the broadcast distribution, the data is discarded when the identifier information transmitted in the signal processing control step is not added to the received data. When the identifier information is added, the data is captured, and when the data identification information of the captured data matches the data identification information included in the distribution request signal, the destination of the data is the data. A communication method in which the terminal address corresponding to identification information is rewritten and the data is transmitted to the terminal device.

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