JP4882756B2 - Viewing situation monitoring method, viewing situation monitoring apparatus, viewing situation monitoring program, and viewing situation monitoring system - Google Patents

Description

  The present invention relates to a viewing situation monitoring method, a viewing situation monitoring apparatus, a viewing situation monitoring program, and a viewing situation monitoring system, and in particular, a viewing situation monitoring method, a viewing situation monitoring apparatus, and a viewing situation monitoring program for monitoring the viewing situation of content distributed by multicast. And a viewing status monitoring system.

  Currently, with the development of information communication technology, content such as voice and video is distributed via a network. A distribution apparatus that distributes content encodes (encodes) the content into a format suitable for transmission over a network, divides the data into predetermined data units (packets), and outputs the data. The playback device that plays back the content receives the packet output from the distribution device via the network, decodes (decodes), and plays back the content.

  By the way, there are unicast distribution and multicast distribution as a method of distributing contents via a network. Unicast distribution is a distribution method in which a distribution apparatus receives a distribution request from a reproduction apparatus and individually transmits packets to the reproduction apparatus. In the unicast distribution, since the distribution apparatus and the reproduction apparatus directly communicate with each other, there is an advantage that it is easy to centrally manage the viewing state of the content on the distribution apparatus side (see, for example, Patent Document 1).

  On the other hand, multicast distribution is a distribution method in which a communication device located on a path from a distribution device to a playback device accepts a transfer request and transmits a copy of the packet to the transmission source of the transfer request. In multicast distribution, packets are appropriately copied by communication devices on the route, so that there is an advantage that the communication amount of the entire network can be suppressed.

  For example, it is assumed that the playback device A receives a packet via a path called communication device ab-c1, and the playback device B receives a packet via a route called communication device ab-c2. At this time, in the unicast distribution, two packets having different destinations are transmitted between the communication apparatuses a and b. In the multicast distribution, only one packet is transmitted between the communication apparatuses a and b. The packet is duplicated.

  Here, with the increase in content distribution via the network, further spread of multicast distribution is expected in the future. However, the conventional multicast distribution has a problem that it is difficult for the distribution apparatus to manage the viewing state of the content.

On the other hand, a distribution method is known in which content is encrypted and distributed, thereby providing an opportunity for direct communication between the distribution device and the playback device (see, for example, Patent Document 2). That is, the distribution device periodically distributes the encrypted content by changing the encryption key, and the playback device acquires the decryption key from the distribution device and decrypts the content every time the encryption key is changed. Thereby, the distribution apparatus can grasp the viewing state of the content by the reproduction apparatus. In addition, since only the decryption key is transmitted between the distribution device and the playback device, the advantage of multicast distribution that the amount of communication can be suppressed can be maintained.
JP 2003-324758 A Japanese Patent Laid-Open No. 10-164046

  However, the technique described in Patent Document 2 has a problem that the playback apparatus must be equipped with dedicated hardware or software corresponding to the above processing. This is because the multicast distribution protocol (communication protocol) does not assume that the playback device directly communicates with the distribution device. In other words, the technique described in Patent Document 2 extends a communication method for multicast distribution, and content cannot be viewed unless the playback device is compatible with the expanded communication method. This is not preferable from the viewpoint of the spread of multicast distribution.

  The present invention has been made in view of these points, and a viewing status monitoring method and a viewing status that can monitor the viewing status of content that is distributed in a multicast manner without changing hardware or software installed in the playback device. An object is to provide a monitoring device, a viewing situation monitoring program, and a viewing situation monitoring system.

  In order to solve the above-described problems, the present invention provides a viewing status monitoring method as shown in FIG. The viewing status monitoring method according to the present invention monitors the viewing status of content distributed by multicast, and reproduces content 4a, 4b, 4c from content distribution devices 3a, 3b that generate packets corresponding to the content. It is executed by the communication device 1 that is located on the route leading to.

  When the communication apparatus 1 receives a transfer request specifying a multicast address for identifying content, the transfer table 1a associates the transmission source of the transfer request with the multicast address and the transfer destination address for identifying the transfer destination apparatus to which the packet is to be transferred. In addition, while registering as a transfer destination device, the transfer table 1a is kept registered while a transfer request is continuously received from the transfer destination device (step S1). Then, the communication device 1 monitors the transfer table 1a, calculates the current number of transfer destinations for each multicast address, and transmits the transfer information indicating the number of transfer destinations to the playback devices 4a, 4b, and 4c receiving the packet. Is continuously transmitted via the network to the management device 2 that manages the viewing information indicating the number of items (step S2).

  According to such a viewing state monitoring method, the communication device 1 registers the transmission source of the transfer request designating the multicast address as the transfer destination device in the transfer table 1a and continuously receives the transfer request. Meanwhile, the registration of the transfer table 1a is maintained. Then, the communication device 1 calculates the current transfer destination number for each multicast address based on the transfer table 1a, and continuously transmits the transfer information indicating the transfer destination number to the management device 2.

  Further, in order to solve the above-mentioned problem, viewing is performed on a route from a distribution device that generates a packet corresponding to content distributed by multicast to one or more reproduction devices that reproduce the content, and monitors the viewing status of the content When the status monitoring device receives a transfer request that associates a multicast address that identifies content with a transfer destination address that identifies a transfer destination device to which a packet is to be transferred, and a transfer request specifying the multicast address, the source of the transfer request Is registered in the transfer table as the transfer destination device, and the transfer table management means for maintaining the transfer table registration while continuously receiving the transfer request from the transfer destination device, and the multicast address by monitoring the transfer table Calculate the current number of transfer destinations for each transfer information that indicates the number of transfer destinations. Provided with a viewing status monitoring device, comprising a transfer status monitoring means for continuously transmitting via a network to a management device that manages viewing information indicating the number of playback devices receiving packets Is done.

  According to such a viewing status monitoring apparatus, the transfer table management means registers the transfer request source specifying the multicast address in the transfer table as the transfer destination apparatus and continuously receives the transfer request. During this time, the transfer table registration is maintained. Then, the transfer status monitoring means calculates the current number of transfer destinations for each multicast address based on the transfer table, and transfer information indicating the number of transfer destinations is continuously transmitted to the management apparatus.

  In addition, in order to solve the above-described problem, the viewing status of content is monitored by a computer located on a route from a distribution device that generates a packet corresponding to content distributed by multicast to one or more reproduction devices that reproduce the content. Transfer table storage means for storing a transfer table for associating a multicast address for identifying content with a transfer destination address for identifying a transfer destination device to which a packet is to be transferred When a transfer request with an address specified is received, the transfer request source is registered in the transfer table as the transfer destination device, and the transfer table registration is maintained while the transfer request is continuously received from the transfer destination device. Transfer table management means, monitor transfer table The current transfer destination number for each multicast address is calculated, and the transfer information indicating the transfer destination number is transmitted to the management device that manages the viewing information indicating the number of playback devices receiving the packet via the network. A viewing status monitoring program is provided, which functions as transfer status monitoring means for continuously transmitting.

  According to the computer that executes such a viewing situation monitoring program, the transfer table management means registers the transfer request source specifying the multicast address in the transfer table as the transfer destination device, and continuously receives the transfer request. While being received, the forwarding table registration is maintained. Then, the transfer status monitoring means calculates the current number of transfer destinations for each multicast address based on the transfer table, and transfer information indicating the number of transfer destinations is continuously transmitted to the management apparatus.

  In order to solve the above-described problem, a viewing status monitoring system that monitors a viewing status of content on a route from a distribution device that generates a packet corresponding to the content distributed by multicast to one or more playback devices that reproduce the content , A transfer table that associates a multicast address that identifies content with a transfer destination address that identifies a transfer destination device to which a packet is to be transferred, and a transfer request that specifies the multicast address, receives the transfer request source as the transfer destination While registering as a device in the forwarding table and continuously receiving forwarding requests from the forwarding destination device, forwarding table management means for maintaining registration of the forwarding table, and monitoring the forwarding table, the current for each multicast address Transfer status monitoring means for calculating the number of transfer destinations A plurality of communication devices, viewing information storage means for storing viewing information indicating the number of playback devices receiving packets for each multicast address, and transfer information indicating the number of transfer destinations from a plurality of communication devices. Transfer information collecting means for continuously collecting information via the network, transfer information collected by the transfer information collecting means is aggregated to generate viewing information, and the generated viewing information is associated with the total time and the viewing information storage means A viewing status monitoring system comprising: a viewing status totaling unit stored in the viewing status management unit.

  According to such a viewing status monitoring system, in each communication device, the transfer table management means registers the transmission source of the transfer request specifying the multicast address in the transfer table as the transfer destination device and continuously transfers it. While the request is received, the forwarding table registration is maintained. Then, the transfer status monitoring unit calculates the current number of transfer destinations for each multicast address based on the transfer table. On the other hand, in the management device, transfer information indicating the number of transfer destinations is continuously collected from a plurality of communication devices by the transfer information collecting means. Then, the transfer information is totaled by the viewing status totaling means, and viewing information indicating the number of playback devices receiving the packet is generated.

  In the present invention, the communication device on the path from the distribution device to the playback device monitors the transfer table that defines the transfer destination of the packet having the multicast address, calculates the current transfer destination number, and continues to the management device. Reported. As a result, it is possible to accurately grasp the viewing status of the content distributed by multicast without changing the distribution device and the reproduction device. Therefore, the administrator or the like can consider the enhancement of the distribution system and the charging method according to the viewing state of the content. In addition, it can be expected that the use of multicast distribution will be further promoted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, an outline of the present embodiment will be described, and then specific contents of the present embodiment will be described.
FIG. 1 is a diagram showing an outline of the present embodiment. The viewing status monitoring system shown in FIG. 1 is a system capable of monitoring the viewing status of content distributed by multicast. The viewing status monitoring system shown in FIG. 1 includes a communication device 1, a management device 2, distribution devices 3a and 3b, and playback devices 4a, 4b, and 4c.

  The communication device 1 is located on a route from the distribution devices 3a and 3b that transmit multicast packets corresponding to the content to the reproduction devices 4a, 4b, and 4c that receive the multicast packets and reproduce the content. The communication device 1 includes a transfer table 1a, a transfer table management unit 1b, a packet transfer unit 1c, and a transfer status monitoring unit 1d.

  The forwarding table 1a stores a multicast address and a forwarding address in association with each other. The multicast address is an IP (Internet Protocol) address for identifying content. The transfer destination address is an IP address that identifies a transfer destination device to which the multicast packet received by the communication device 1 is to be transferred next. As the transfer destination device, a playback device and other communication devices are conceivable.

  The forwarding table management unit 1b receives a forwarding request designating a multicast address. Here, when the transmission source of the transfer request is not registered in the transfer table 1a, the transfer table management unit 1b newly registers the transmission source of the transfer request. Further, when the transmission source of the transfer request is registered in the transfer table 1a, the registration of the transfer table 1a is maintained. On the other hand, the transfer table management unit 1b deletes, from the transfer table 1a, transfer destination devices that have not transmitted transfer requests continuously for a predetermined time or more among the transfer destination devices registered in the transfer table 1a.

  The packet transfer means 1c receives the multicast packet transmitted by the distribution devices 3a and 3b. Here, the packet transfer means 1c refers to the transfer table 1a and specifies a transfer destination device corresponding to the received multicast packet. At this time, if there is no corresponding transfer destination device, the received multicast packet is discarded. On the other hand, if there are two or more corresponding transfer destination devices, a copy of the received multicast packet is created. Then, the packet transfer unit 1c transmits the multicast packet to the transfer destination device.

  The transfer status monitoring unit 1d monitors the transfer table 1a and calculates the current number of transfer destinations for each multicast address. Then, the transfer status monitoring unit 1 d transmits transfer information indicating the number of transfer destinations to the management device 2. Note that the transfer information can be transmitted by, for example, a method of transmitting in response to a report request from the management device 2 or a method of transmitting to the management device 2 every time the number of transfer destinations changes.

The management device 2 is connected to the communication device 1 via a network. The management device 2 includes a viewing information storage unit 2a, a transfer information collection unit 2b, and a viewing status totaling unit 2c.
The viewing information storage means 2a stores viewing information for each multicast address in time series. The viewing information is information indicating the number of playback devices that have received a multicast packet at a certain time.

  The transfer information collection unit 2 b continuously collects transfer information from the communication device 1. The transfer information can be collected by, for example, a method of transmitting a report request to the communication device 1 at a predetermined time interval and a method of waiting for the communication device 1 to transmit the transfer information. When there is another communication device having the same function as that of the communication device 1, the transfer information collection unit 2b collects transfer information also from the other communication device.

  The viewing status totaling unit 2c totals the transfer information collected by the transfer information collecting unit 2b to generate viewing information. Then, the viewing status totaling unit 2c stores the generated viewing information in the viewing information storage unit 2a in association with the totaling time.

  Here, it is assumed that the distribution device 3a distributes the content X and the distribution device 3b by multicast distribution, the reproduction devices 4a and 4b view the content X, and the reproduction device 4c views the content Y. In addition, it is assumed that the playback devices 4a, 4b, and 4c are connected to the communication device 1 without passing through other communication devices.

  At this time, the playback devices 4a, 4b, and 4c specify a multicast address corresponding to the content to be viewed and continuously transmit a transfer request to the communication device 1. The communication device 1 receives the transfer request, associates the content X with the playback devices 4a and 4b, and associates the content Y with the playback device 4c, registers them in the transfer table 1a, and maintains them.

  Then, the communication device 1 transfers the multicast packet transmitted from the distribution device 3a to the reproduction devices 4a and 4b and transfers the multicast packet transmitted from the distribution device 3b to the reproduction device 4c. Further, the communication device 1 monitors the transfer table 1 a and transmits to the management device 2 transfer information indicating that the number of content X transfer destinations is 2 and the content Y transfer destination number is 1.

  According to such a viewing status monitoring system, the communication device 1 registers the transmission source of the transfer request designating the multicast address as the transfer destination device in the transfer table 1a and continuously receives the transfer request. Meanwhile, the registration of the transfer table 1a is maintained. Next, the multicast packet having the multicast address registered in the forwarding table 1a is forwarded to all corresponding forwarding destination devices. Then, based on the forwarding table 1a, the current number of forwarding destinations for each multicast address is calculated, and forwarding information indicating the number of forwarding destinations is transmitted to the management apparatus 2. On the other hand, transfer information is continuously collected from the communication device 1 and other communication devices by the management device 2, and the transfer information is aggregated to generate viewing information indicating the viewing status of the content.

  As a result, it is possible to grasp the viewing status of the content distributed by multicast without changing the distribution devices 3a, 3b and the reproduction devices 4a, 4b, 4c. In particular, the administrator can know the time-series change of the viewing status for each content by browsing the time-series viewing information accumulated in the management device 2. Therefore, the administrator can appropriately consider the enhancement of the distribution device and the communication device, the charging method when viewing the content, and the like, and can realize more stable content distribution.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 2 is a diagram showing a system configuration of the present embodiment. The content distribution system according to the first embodiment is a system that distributes video captured by a camera in multicast in real time.

  The content distribution system shown in FIG. 2 includes networks 21, 22, cameras 31, 32, distribution servers 41, 42, clients 51, 52, 53, 54, routers 100, 200, L2 (Layer 2) switches 300, 400, video. Name server 500 and audience rating server 600.

  Distribution servers 41 and 42, router 200, video name server 500 and audience rating server 600 are connected to network 21. The router 200 is located at the boundary between the outside and the inside of the network 21. A camera 31 is connected to the distribution server 41. A camera 32 is connected to the distribution server 42.

  A router 100 and L2 switches 300 and 400 are connected to the network 22. The router 100 is located at the boundary between the outside and the inside of the network 22. The router 100 is connected to the router 200. Clients 51 and 52 are connected to the L2 switch 300. Clients 53 and 54 are connected to the L2 switch 400.

  The camera 31 captures an image at a predetermined position. The distribution server 41 encodes video captured by the camera 31 into a predetermined data format. Then, the distribution server 41 distributes the encoded video data by multicast in real time. That is, the distribution server 41 outputs a multicast packet corresponding to the video data to the network 21. Similarly, the distribution server 42 acquires the video imaged by the camera 32, and multicasts the encoded video data in real time.

  The clients 51, 52, 53, and 54 can receive the multicast packet output from the distribution servers 41 and 42 and reproduce the video captured by the cameras 31 and 32. For example, when a video to be played is selected by a user operation input, the client 51 designates a multicast address corresponding to the selected video and outputs a Join request. Thereby, transfer of the multicast packet to the client 51 is started.

  Further, the client 51 periodically outputs a Join request while continuing to play back the video. For example, the client 51 outputs a join request at intervals of 30 seconds. When a playback stop is instructed by a user operation input, a Leave request is output. Thereby, the transfer of the multicast packet to the client 51 is stopped. The clients 52, 53, and 54 can also reproduce the video by performing the same processing.

  The routers 100 and 200 are communication devices that perform communication processing in the third layer (network layer). Therefore, the routers 100 and 200 control the transfer destination of a normal IP packet (unicast packet) according to the destination address.

  Furthermore, the routers 100 and 200 control the forwarding destination of the multicast packet. That is, the routers 100 and 200 register the IP address of the client or communication apparatus that is transmitting the Join request in the table, and transfer the received multicast packet to the registered transfer destination. If there is no registered forwarding destination, the received multicast packet is discarded.

  In order to receive the multicast packet, the router 100 continuously join requests to the router 200, which is a communication device close to the distribution servers 41 and 42, while at least one transfer destination is registered in the table. Send.

  The L2 switch 300 is a communication device that performs communication processing of the second layer (data link layer). Therefore, the L2 switch 300 cannot control the multicast packet transfer destination. For this reason, when the L2 switch 300 receives the Join request and the Leave request from the clients 51 and 52, the L2 switch 300 transfers the Join request and the Leave request to the router 100 as they are. Further, when a multicast packet is received from the router 100, the multicast packet is transferred to both the client 51 and the client 52.

  Similar to the L2 switch 300, the L2 switch 400 is a communication device that performs layer 2 communication processing. However, the L2 switch 400 has an IGMP (Internet Group Management Protocol) snooping function. IGMP snooping refers to performing processing according to the contents of a multicast packet in the L2 switch. That is, the L2 switch 400 can perform communication processing similar to that of the routers 100 and 200 for multicast packets.

  The video name server 500 is a computer that manages the correspondence between the names of videos taken by the cameras 31 and 32 and the multicast addresses assigned to the videos. The clients 51, 52, 53, and 54 can specify the multicast address from the name of the video by using the video name server 500.

  The audience rating server 600 collects multicast packet transfer status information from the routers 100 and 200 and the L2 switch 400, and periodically aggregates the information. Then, the audience rating server 600 holds the counting result as viewing information. The audience rating server 600 collects information from the routers 100 and 200 and the L2 switch 400 because these communication apparatuses hold a table used for forwarding multicast packets.

  Here, in this embodiment, it is assumed that the IP addresses of the clients 51, 52, 53, and 54 are addresses C1, C2, C3, and C4, respectively. Further, assume that the IP addresses of the routers 100 and 200 and the L2 switches 300 and 400 are addresses R1, R2, R3, and R4, respectively.

  FIG. 3 is a diagram illustrating a hardware configuration of the audience rating server. The audience rating server 600 is entirely controlled by a CPU (Central Processing Unit) 601. A RAM (Random Access Memory) 602, a hard disk drive (HDD: Hard Disk Drive) 603, a graphic processing device 604, an input interface 605, and a communication interface 606 are connected to the CPU 601 through a bus 607.

  The RAM 602 temporarily stores at least part of an OS (Operating System) program and application programs to be executed by the CPU 601. The RAM 602 stores various data necessary for processing by the CPU 601. The HDD 603 stores an OS and application programs.

  A monitor 11 is connected to the graphic processing device 604. The graphic processing device 604 displays an image on the screen of the monitor 11 in accordance with a command from the CPU 601. A keyboard 12 and a mouse 13 are connected to the input interface 605. The input interface 605 transmits a signal sent from the keyboard 12 or the mouse 13 to the CPU 601 via the bus 607. The communication interface 606 is connected to the network 21. The communication interface 606 transmits and receives data to and from other computers via the network 21.

  The distribution servers 41 and 42, the clients 51, 52, 53, and 54 and the video name server 500 can be realized by the same hardware configuration as the audience rating server 600. The routers 100 and 200 and the L2 switches 300 and 400 can also be realized using a computer. In this case, the routers 100 and 200 and the L2 switches 300 and 400 can also be realized by a hardware configuration similar to that of the audience rating server 600.

With the hardware configuration as described above, the processing functions of the present embodiment can be realized.
Next, module configurations of the router 100 and the audience rating server 600 will be described.

  FIG. 4 is a block diagram illustrating functions of the router according to the first embodiment. The router 100 includes a routing information storage unit 110, a multicast information storage unit 120, a transfer information storage unit 130, an input control unit 140, a route determination unit 150, a multicast processing unit 160, a transfer status monitoring unit 170, and an output control unit 180.

  The routing information storage unit 110 stores a routing table that defines a correspondence relationship between a packet destination and a transfer destination to which the packet is transferred next. In the routing table, one transfer destination address is specified for one destination address.

  The multicast information storage unit 120 stores a multicast table that defines the correspondence between the multicast address and the client or communication device that is sending the Join request. In the multicast table, IP addresses of zero or more clients or communication devices are specified for one multicast address.

  The transfer information storage unit 130 stores transfer information indicating the current number of transfer destinations for each multicast address. However, the number of transfer destinations is calculated excluding other communication devices having a multicast packet transfer control function. Accordingly, the router 200 and the L2 switch 400 are excluded, and the transfer destination number is calculated.

  The input control unit 140 includes a queue that temporarily stores packets. The input control unit 140 receives the packet transferred from the router 200 or the L2 switches 300 and 400, and adds the received packet to the tail of the queue. Further, the input control unit 140 sequentially extracts the packets stored in the queue from the top, and sends them to any of the route determination unit 150, the multicast processing unit 160, and the transfer status monitoring unit 170 according to the type of the packet.

  Specifically, a packet in which a multicast address is set as the destination address is sent to the multicast processing unit 160. The packet in which the multicast address is set includes a packet indicating a Join request and a Leave request.

  The packet addressed to the router 100 is sent to the transfer status monitoring unit 170. It is assumed that the audience rating server 600 transmits a packet addressed to the router 100. Packets not corresponding to the above are sent to the route determination unit 150.

  When the route determination unit 150 obtains a packet from the input control unit 140, the multicast processing unit 160, or the transfer status monitoring unit 170, the route determination unit 150 refers to the routing table stored in the routing information storage unit 110 and corresponds to the designated destination. Specify the forwarding destination. Then, the route determination unit 150 specifies a communication interface corresponding to the identified transfer destination, and sends the packet to the output control unit 180.

  When the multicast processing unit 160 obtains a Join request packet from the input control unit 140, the multicast processing unit 160 updates the multicast table stored in the multicast information storage unit 120. Here, when the source of the Join request is not registered for the designated multicast address, the multicast processing unit 160 newly registers.

  Furthermore, when there is no other registered transfer destination for the designated multicast address, the multicast processing unit 160 transmits a Join request packet to the communication device close to the distribution server that outputs the corresponding multicast packet. The route determination unit 150 is instructed to do so. The route determination unit 150 can know that the communication device close to the distribution server outputting the multicast packet is the router 200 by referring to the routing table.

  In addition, when the multicast processing unit 160 obtains the Leave request packet from the input control unit 140, the multicast processing unit 160 deletes the transmission source of the Leave request from the multicast table for the designated multicast address. Further, when there is no other forwarding destination for the designated multicast address, the multicast processing unit 160 transmits a Leave request packet to the communication device close to the distribution server outputting the corresponding multicast packet. Instructs the route determination unit 150.

  In addition, the multicast processing unit 160 monitors the multicast table, and deletes from the multicast table a transfer destination that has passed a predetermined time since the last Join request was acquired. This is because the clients 51, 52, 53, and 54 may be shut down without outputting a Leave request.

  Further, when the multicast processing unit 160 acquires the multicast packet output from the distribution servers 41 and 42 from the input control unit 140, the multicast processing unit 160 refers to the multicast table and identifies the corresponding transfer destination. Here, when there is no corresponding transfer destination, the multicast processing unit 160 discards the acquired multicast packet. When there are two or more corresponding transfer destinations, the necessary number of multicast packets are duplicated. Then, the multicast processing unit 160 instructs the route determination unit 150 to transmit a multicast packet to each identified transfer destination.

  The transfer status monitoring unit 170 monitors the multicast table stored in the multicast information storage unit 120. Here, the transfer status monitoring unit 170 calculates the number of transfer destinations for each multicast address each time the transfer destination registration status changes. However, as described above, the calculation is performed excluding the router 200 and the L2 switch 400. Then, the transfer status monitoring unit 170 stores transfer information indicating the calculated transfer destination number in the transfer information storage unit 130.

  It is possible to know that the router 200 and the L2 switch 400 are communication devices having a multicast packet transfer control function by monitoring packets processed by the route determination unit 150. For example, the transfer status monitoring unit 170 can determine that a device that is a packet transmission source according to a specific communication protocol is a communication device having a multicast packet transfer control function.

  Further, the transfer status monitoring unit 170 acquires transfer information from the transfer information storage unit 130 and sends the transfer information to the route determination unit 150 as a packet addressed to the audience rating server 600. Here, there are the following two methods for transmitting the transfer information to the audience rating server 600. The administrator sets which method to use in the transfer status monitoring unit 170 in advance.

  The first method is a method of transmitting transfer information in response to a report request that the audience rating server 600 periodically outputs. That is, when the transfer status monitoring unit 170 acquires a packet indicating a report request from the input control unit 140, the transfer status monitoring unit 170 generates a transfer information packet. The second method is a method of transmitting transfer information to the audience rating server 600 every time the number of transfer destinations increases or decreases. Note that the first method and the second method may be combined.

  The output control unit 180 includes a queue for temporarily storing packets for each communication interface. Specifically, the output control unit 180 includes two queues for the outside and the inside of the network 22. When the output control unit 180 acquires a packet from the route determination unit 150, the output control unit 180 adds the acquired packet to the tail of the queue corresponding to the designated communication interface. Further, the output control unit 180 sequentially extracts the packets stored in the respective queues from the top and outputs the packets from the corresponding communication interface.

  FIG. 5 is a block diagram illustrating functions of the audience rating server according to the first embodiment. The audience rating server 600 includes a transfer information collection unit 610, a transfer information storage unit 620, a viewing status totaling unit 630, and a viewing information storage unit 640.

  The transfer information collection unit 610 continuously collects transfer information from the routers 100 and 200 and the L2 switch 400. Then, the transfer information collection unit 610 sequentially stores the transfer information acquired from each communication device in the transfer information storage unit 620.

  Here, the administrator presets a transfer information collection method in accordance with the transfer information transmission method set in the routers 100 and 200 and the L2 switch 400. That is, when the first method is adopted as the transfer information transmission method, the transfer information collection unit 610 periodically outputs a report request to the routers 100 and 200 and the L2 switch 400. For example, the transfer information collection unit 610 outputs report requests at 10-minute intervals. On the other hand, when the second method is adopted as the transfer information transmission method, the transfer information collection unit 610 waits for transfer information to be transmitted from the routers 100 and 200 and the L2 switch 400.

  When the first method is adopted, the administrator can select either UDP (User Datagram Protocol) or TCP (Transmission Control Protocol) as the communication protocol. UDP has a high transfer rate but low reliability. On the other hand, TCP has high reliability but low transfer speed. Therefore, it is preferable to select a communication protocol to be used in consideration of the congestion degree of the network, the packet loss rate, and the like.

  The viewing status totaling unit 630 counts the number of clients receiving multicast packets for each multicast address based on the transfer information stored in the transfer information storage unit 620. For example, the viewing status totaling unit 630 counts every 10 minutes. Further, when the transfer information collection unit 610 cannot acquire transfer information from some communication devices, the communication device performs aggregation using the transfer information acquired normally last.

  Then, the viewing status totaling unit 630 associates the number of clients for each multicast address and the totaling time, and stores them in the viewing information storage unit 640 as viewing information. Thus, information indicating the viewing status of the content is accumulated in the viewing information storage unit 640 in time series.

  The router 200 can also be realized by the same module configuration as the router 100. Further, the L2 switch 400 can also be realized by a module configuration similar to that of the router 100 for processing of multicast packets.

Next, the data structure of data held by the video name server 500, the router 100, and the audience rating server 600 will be described.
FIG. 6 shows the data structure of the video name table. The video name table 511 illustrated in FIG. 6 is managed by the video name server 500. The video name table 511 includes an item indicating a video name and an item indicating a multicast address. Information arranged in the horizontal direction of each item is associated with each other.

  In the video name item, the name of the video distributed by the distribution servers 41 and 42 is set. For example, the video name of the video distributed by the distribution server 41 is set as “video at point A”, and the video name of the video distributed by the distribution server 42 is set as “video at point B”.

  In the multicast address item, a multicast address assigned to each video is set. For example, “239.199.75.11” (corresponding to the address M1 in FIG. 2) for the video distributed by the distribution server 41, and “239.199.75.12” for the video distributed by the distribution server 42. (Corresponding to the address M2 in FIG. 2) is set.

  The information stored in the video name table 511 is registered in advance by the administrator before starting the video distribution. When a video name is input, the video name server 500 refers to the video name table 511 and outputs a corresponding multicast address. Therefore, the clients 51, 52, 53, and 54 do not need to store a multicast address in order to view the video.

  FIG. 7 is a diagram illustrating a data structure of the routing table. The routing table 111 illustrated in FIG. 7 is stored in the routing information storage unit 110 of the router 100. The routing table 111 includes an item indicating a destination network, an item indicating a netmask, an item indicating a gateway, and an item indicating an interface. Information arranged in the horizontal direction of each item is associated with each other.

  In the destination network item, a network address for identifying a network or an IP address for identifying a device is set. For example, “10.74.1.10.1” (corresponding to the address C1 in FIG. 2) is set for the client 51, and “10.74.30.0” is set for the network 21.

  In the item of netmask, a bit string for distinguishing the network part and the host part of the address set in the destination network is set. For example, “255.255.255.255” means that the address set in the destination network is an IP address that identifies the device. “255.255.255.0” means that the upper 24 bits of the address set in the destination network are a part for identifying the network.

  In the gateway item, the IP address of the transfer destination to which the packet corresponding to the address range specified by the destination network and the netmask is transferred next is set. For example, the IP address “10.74.30.1” (corresponding to the address R2 in FIG. 2) of the router 200 is set for a packet addressed to a device belonging to the network 21.

  In the interface item, a character string for identifying a communication interface used for transmitting a packet to the gateway is set. For example, when the gateway is the router 200, “net1” indicating a communication interface for the outside of the network 22 is set.

  Information stored in the routing table 111 is registered in advance by an administrator. Note that the router 100 may dynamically update the routing table 111 by communicating with other communication devices according to a routing protocol such as RIP (Routing Information Protocol). In this case, when the network configuration is changed, the registered contents of the routing table 111 are automatically changed.

  FIG. 8 shows the data structure of the multicast table. The multicast table 121 illustrated in FIG. 8 is stored in the multicast information storage unit 120 of the router 100. The multicast table 121 includes an item indicating a multicast address, an item indicating a recipient address, and an item indicating an update time. Information arranged in the horizontal direction of each item is associated with each other.

  In the item of multicast address, a multicast address for identifying a video is set. The IP address of the client or communication device to which the multicast packet is transferred is set in the receiver address item. Zero or more recipient addresses are set for one multicast address. In the update time item, the time when the router 100 last received the Join request is set. Recipient addresses whose predetermined time or more has elapsed from the update time are deleted from the multicast table 121.

  Information stored in the multicast table 121 is appropriately updated by the multicast processing unit 160. Here, since the L2 switch 300 does not perform multicast address transfer destination control, the IP addresses of the clients 51 and 52 connected to the L2 switch 300 are directly registered. On the other hand, since the L2 switch 400 performs multicast address transfer destination control, the IP address of the L2 switch 400 is registered for the clients 53 and 54 connected to the L2 switch 400.

Note that the transfer information storage unit 620 of the audience rating server 600 stores a table similar to the transfer information table 131 for each communication device.
FIG. 9 illustrates a data structure of the transfer information table according to the first embodiment. The transfer information table 131 illustrated in FIG. 9 is stored in the transfer information storage unit 130 of the router 100. The transfer information table 131 includes an item indicating a multicast address and an item indicating the number of transfer destinations. Information arranged in the horizontal direction of each item is associated with each other.

  In the item of multicast address, a multicast address for identifying a video is set. In the item of the transfer destination number, the current transfer destination number of the multicast packet is set. As described above, the transfer destination number is calculated by excluding the router 200 and the L2 switch 400. Information stored in the transfer information table 131 is appropriately updated by the transfer status monitoring unit 170.

  FIG. 10 is a diagram illustrating a data structure of the viewing information table according to the first embodiment. The viewing information table 641 shown in FIG. 10 is stored in the viewing information storage unit 640 of the audience rating server 600. The viewing information table 641 is provided with an item indicating the date, an item indicating the multicast address, and an item indicating the number of views. Information arranged in the horizontal direction of each item is associated with each other.

  In the date and time item, the date and time when the viewing status totaling unit 630 performs the totaling process is set. In the item of multicast address, a multicast address for identifying a video is set. The total number of transfer destinations in all communication devices is set in the viewing number item. Information stored in the viewing information table 641 is periodically added by the viewing status totaling unit 630.

Next, details of processing executed in the system having the above-described configuration and data structure will be described.
FIG. 11 is a first sequence diagram showing a flow of multicast distribution. The sequence diagram shown in FIG. 11 is for the case where the client 51 views “video at the point A”, and the first method (the audience rating server 600 periodically outputs a report request) as a transfer information collection method. This is an example when the method is adopted. In the following, the process illustrated in FIG. 11 will be described in order of step number.

  [Step S <b> 11] The distribution server 41 acquires the video captured by the camera 31 and outputs a multicast packet having the address M <b> 1 to the network 21. The output multicast packet reaches the router 200. However, since the transfer destination is unregistered, the router 200 discards the received multicast packet.

[Step S12] The client 51 transmits a search request designating the video name “video at point A” to the video name server 500.
[Step S13] The video name server 500 replies to the client 51 with the address M1 (“239.199.75.11”) corresponding to the designated video name.

  [Step S14] The client 51 outputs a Join request in which the destination address is the address M1 and the transmission source address is the address C1. The output Join request reaches the L2 switch 300. The L2 switch 300 transfers the received Join request to the router 100 as it is.

  [Step S15] The router 100 receives a Join request from the client 51. Then, the router 100 registers the address C1 of the client 51 in the multicast table in association with the address M1.

[Step S16] The router 100 transmits to the router 200 a Join request with the destination address as the address M1 and the source address as the address R1.
[Step S17] The router 200 receives the Join request from the router 100. Then, the router 200 registers the address R1 of the router 100 in the multicast table in association with the address M1.

[Step S18] The router 200 starts forwarding a multicast packet having the address M1 to the router 100.
[Step S19] The router 100 receives a multicast packet having an address M1 from the router 200. Then, the router 100 outputs the received multicast packet to the network 22. The output multicast packet reaches the L2 switch 300. The L2 switch 300 transfers the received multicast packet to both the clients 51 and 52 as they are. In the client 52, the transferred multicast packet is discarded.

  [Step S20] The client 51 outputs a Join request similar to that in Step S14 after a predetermined time has elapsed from Step S14. The output Join request reaches the router 100 via the L2 switch 300.

[Step S21] The router 100 changes the update time corresponding to the client 51 in the multicast table.
[Step S22] The router 100 transmits a Join request similar to that in step S16 to the router 200 after a predetermined time has elapsed from step S16.

[Step S23] The router 200 changes the update time corresponding to the router 100 in the multicast table.
[Step S24a] The audience rating server 600 transmits a report request to the router 200.

  [Step S25a] The router 200 transmits the latest transfer information to the audience rating server 600 in response to the report request. Here, the number of transfer destinations for the address M1 is zero. The audience rating server 600 holds the received transfer information.

  [Step S24b] The audience rating server 600 transmits a report request to the router 100. Note that the audience rating server 600 does not need to send a report request after waiting for a response in step S15a.

  [Step S25b] In response to the report request, the router 100 transmits the latest transfer information to the audience rating server 600. Here, the number of transfer destinations for the address M1 is one. The audience rating server 600 holds the received transfer information.

  [Step S26] Upon receiving an instruction to end viewing by the user, the client 51 outputs a Leave request with the destination address as the address M1 and the source address as the address C1. The output Leave request reaches the L2 switch 300. The L2 switch 300 transfers the received Leave request to the router 100 as it is.

  [Step S27] The router 100 receives the Leave request from the client 51. Then, the router 100 deletes the registration of the client 51 for the address M1 from the multicast table. Thereby, the transfer of the multicast packet to the client 51 is stopped.

  [Step S28] When the number of transfer destinations for the address M1 becomes 0 by the deletion process in step S27, the router 100 transmits a Leave request with the destination address as the address M1 and the source address as the address R1 to the router 200. .

  [Step S29] The router 200 receives the Leave request from the router 100. Then, the router 200 deletes the registration of the router 100 for the address M1 from the multicast table. Thereby, the transfer of the multicast packet to the router 100 stops.

  In this way, the client 51 outputs a Join request at the start of viewing. Then, the router 100 registers the client 51 in the multicast table, and the router 200 registers the router 100 in the multicast table. Accordingly, the multicast packet is relayed from the distribution server 41 to the router 200, the router 100, and the client 51. At this time, the audience rating server 600 periodically collects transfer information from the routers 100 and 200 and aggregates the transfer information to generate viewing information.

  FIG. 12 is a second sequence diagram illustrating a flow of multicast distribution. The sequence diagram shown in FIG. 12 is for the case where the client 51 views “video at point A”, and the second method (the communication device appropriately transmits the transfer information to the audience rating server 600) as a transfer information collection method. This is an example in the case of adopting the method. In the following, the process illustrated in FIG. 12 will be described in order of step number.

  [Step S <b> 31] The distribution server 41 acquires the video captured by the camera 31 and outputs a multicast packet having the address M <b> 1 to the network 21. The output multicast packet reaches the router 200.

[Step S <b> 32] The client 51 transmits a search request designating the video name “video at point A” to the video name server 500.
[Step S33] The video name server 500 replies to the client 51 with an address M1 corresponding to the specified video name.

  [Step S34] The client 51 outputs a Join request with the destination address as the address M1 and the transmission source address as the address C1. The output Join request reaches the router 100 via the L2 switch 300.

  [Step S35] The router 100 receives a Join request from the client 51. Then, the router 100 registers the address C1 of the client 51 in the multicast table in association with the address M1.

[Step S36] The router 100 transmits the latest transfer information to the audience rating server 600 because the number of transfer destinations is increased by the registration process in step S25.
[Step S37] The router 100 transmits to the router 200 a Join request with the address M1 as the destination address and the address R1 as the source address.

  [Step S38] The router 200 receives the Join request from the router 100. Then, the router 200 registers the address R1 of the router 100 in the multicast table in association with the address M1. Since the router 100 is excluded when calculating the number of transfer destinations, the number of transfer destinations does not change before and after the registration process. For this reason, the router 200 does not transmit transfer information to the audience rating server 600.

[Step S39] The router 200 starts forwarding a multicast packet having the address M1 to the router 100.
[Step S40] The router 100 receives a multicast packet having an address M1 from the router 200. Then, the router 100 outputs the received multicast packet to the network 22. The output multicast packet reaches the clients 51 and 52 via the L2 switch 300.

  [Step S41] The client 51 outputs a Join request similar to that in Step S34 after a predetermined time has elapsed from Step S34. The output Join request reaches the router 100 via the L2 switch 300.

[Step S42] The router 100 changes the update time corresponding to the client 51 in the multicast table.
[Step S43] After a predetermined time has elapsed from step S37, the router 100 transmits a Join request similar to that in step S37 to the router 200.

[Step S44] The router 200 changes the update time corresponding to the router 100 in the multicast table.
[Step S45] When the user gives an instruction to end viewing, the client 51 outputs a Leave request with the destination address as the address M1 and the source address as the address C1. The output Leave request is delivered to the router 100 via the L2 switch 300.

  [Step S46] The router 100 receives the Leave request from the client 51. Then, the router 100 deletes the registration of the client 51 for the address M1 from the multicast table.

[Step S47] The router 100 transmits the latest transfer information to the audience rating server 600 because the number of transfer destinations is reduced by the deletion process in step S46.
[Step S48] When the number of transfer destinations for the address M1 becomes 0 by the deletion processing in step S46, the router 100 transmits a Leave request with the destination address as the address M1 and the source address as the address R1 to the router 200. .

  [Step S49] The router 200 receives the Leave request from the router 100. Then, the router 200 deletes the registration of the router 100 for the address M1 from the multicast table.

  In this way, the client 51 outputs a Join request at the start of viewing. Then, the router 100 registers the client 51 in the multicast table, and the router 200 registers the router 100 in the multicast table. Accordingly, the multicast packet is relayed from the distribution server 41 to the router 200, the router 100, and the client 51. Here, the router 100 transmits the transfer information to the audience rating server 600 when the client 51 is registered.

  FIG. 13 is a third sequence diagram illustrating a flow of multicast distribution. The sequence diagram shown in FIG. 13 is for the case where the client 53 views “video at the point A”, and the first method (the audience rating server 600 periodically outputs a report request) as a transfer information collection method. This is an example when the method is adopted. However, unlike the case of FIG. 11, the description of continuous Join request transmission is omitted. In the following, the process illustrated in FIG. 13 will be described in order of step number.

  [Step S <b> 51] The distribution server 41 acquires the video captured by the camera 31 and outputs a multicast packet having the address M <b> 1 to the network 21. The output multicast packet reaches the router 200.

[Step S <b> 52] The client 53 transmits a search request designating the video name “video at point A” to the video name server 500.
[Step S53] The video name server 500 returns an address M1 corresponding to the specified video name to the client 53.

  [Step S54] The client 53 outputs a Join request with the address M1 as the destination address and the address C3 as the source address. The output Join request reaches the L2 switch 400.

  [Step S55] The L2 switch 400 receives a Join request from the client 53. Then, the L2 switch 400 registers the address C3 of the client 53 in the multicast table in association with the address M1.

[Step S56] The L2 switch 400 transmits to the router 100 a Join request in which the destination address is the address M1 and the transmission source address is the address R4.
[Step S57] The router 100 receives the Join request from the L2 switch 400. Then, the router 100 registers the address R4 of the L2 switch 400 in the multicast table in association with the address M1.

[Step S58] The router 100 transmits to the router 200 a Join request with the destination address as the address M1 and the source address as the address R1.
[Step S59] The router 200 receives the Join request from the router 100. Then, the router 200 registers the address R1 of the router 100 in the multicast table in association with the address M1.

[Step S60] The router 200 starts forwarding the multicast packet having the address M1 to the router 100.
[Step S61] The router 100 receives a multicast packet having an address M1 from the router 200. Then, the router 100 outputs the received multicast packet to the network 22. The output multicast packet reaches the L2 switch 400.

  [Step S62] The L2 switch 400 receives the multicast packet having the address M1 from the router 100. Then, the L2 switch 400 transmits the received multicast packet to the client 53.

[Step S63a] The audience rating server 600 transmits a report request to the router 200.
[Step S64a] The router 200 transmits the latest transfer information to the audience rating server 600 in response to the report request. Here, the number of transfer destinations for the address M1 is zero.

  [Step S63b] The audience rating server 600 transmits a report request to the router 100. Note that the audience rating server 600 does not need to send a report request after waiting for a response in step S64a.

  [Step S64b] In response to the report request, the router 100 transmits the latest transfer information to the audience rating server 600. Here, the number of transfer destinations for the address M1 is zero.

  [Step S63c] The audience rating server 600 transmits a report request to the L2 switch 400. Note that the audience rating server 600 does not need to send a report request after waiting for a response in step S64b.

  [Step S64c] The L2 switch 400 transmits the latest transfer information to the audience rating server 600 in response to the report request. Here, the number of transfer destinations for the address M1 is one.

  [Step S65] Upon receiving an instruction to end viewing by the user, the client 53 outputs a Leave request with the destination address as the address M1 and the transmission source address as the address C3. The output Leave request reaches the L2 switch 400.

  [Step S66] The L2 switch 400 receives the Leave request from the client 53. Then, the L2 switch 400 deletes the registration of the client 53 for the address M1 from the multicast table.

  [Step S67] When the number of transfer destinations for the address M1 becomes zero as a result of the deletion process in step S66, the L2 switch 400 transmits a Leave request with the destination address as the address M1 and the source address as the address R4 to the router 100. To do.

  [Step S68] The router 100 receives the Leave request from the L2 switch 400. Then, the router 100 deletes the registration of the L2 switch 400 for the address M1 from the multicast table.

  [Step S69] When the number of transfer destinations for the address M1 becomes 0 by the deletion process in step S68, the router 100 transmits a Leave request with the destination address as the address M1 and the source address as the address R1 to the router 200. .

  [Step S70] The router 200 receives the Leave request from the router 100. Then, the router 200 deletes the registration of the router 100 for the address M1 from the multicast table.

  In this way, the client 53 outputs a Join request at the start of viewing. Then, the L2 switch 400 registers the client 53 in the multicast table, the router 100 registers the L2 switch 400 in the multicast table, and the router 200 registers the router 100 in the multicast table. As a result, the multicast packet is relayed from the distribution server 41 to the router 200, the router 100, the L2 switch 400, and the client 51. At this time, the audience rating server 600 periodically collects transfer information from the L2 switch 400 and the routers 100 and 200, and aggregates the transfer information to generate viewing information.

  FIG. 14 is a fourth sequence diagram illustrating a flow of multicast distribution. The sequence diagram shown in FIG. 14 is for the case where the client 53 views “video at point A”, and the second method (the communication device appropriately transmits the transfer information to the audience rating server 600) as a transfer information collection method. This is an example in the case of adopting the method. However, unlike the case of FIG. 12, the description of continuous Join request transmission is omitted. In the following, the process illustrated in FIG. 14 will be described in order of step number.

  [Step S <b> 71] The distribution server 41 acquires the video captured by the camera 31 and outputs a multicast packet having the address M <b> 1 to the network 21. The output multicast packet reaches the router 200.

[Step S <b> 72] The client 53 transmits a search request designating the video name “video at point A” to the video name server 500.
[Step S73] The video name server 500 returns an address M1 corresponding to the specified video name to the client 53.

  [Step S74] The client 53 outputs a Join request with the destination address as the address M1 and the source address as the address C3. The output Join request reaches the L2 switch 400.

  [Step S75] The L2 switch 400 receives a Join request from the client 53. Then, the L2 switch 400 registers the address C3 of the client 53 in the multicast table in association with the address M1.

[Step S76] The L2 switch 400 transmits the latest transfer information to the audience rating server 600 because the number of transfer destinations is increased by the registration process in step S75.
[Step S77] The L2 switch 400 transmits to the router 100 a Join request with the destination address being the address M1 and the transmission source address being the address R4.

  [Step S78] The router 100 receives the Join request from the L2 switch 400. Then, the router 100 registers the address R4 of the L2 switch 400 in the multicast table in association with the address M1. Since the L2 switch 400 is excluded when calculating the number of transfer destinations, the number of transfer destinations does not change before and after the registration process. For this reason, the router 100 does not transmit transfer information to the audience rating server 600.

[Step S79] The router 100 transmits to the router 200 a Join request with the destination address as the address M1 and the source address as the address R1.
[Step S80] The router 200 receives a Join request from the router 100. Then, the router 200 registers the address R1 of the router 100 in the multicast table in association with the address M1.

[Step S81] The router 200 starts forwarding a multicast packet having the address M1 to the router 100.
[Step S82] The router 100 receives a multicast packet having an address M1 from the router 200. Then, the router 100 outputs the received multicast packet to the network 22. The output multicast packet reaches the L2 switch 400.

  [Step S83] The L2 switch 400 receives the multicast packet having the address M1 from the router 100. Then, the L2 switch 400 transmits the received multicast packet to the client 53.

  [Step S84] When the user gives an instruction to end viewing, the client 53 outputs a Leave request with the destination address as the address M1 and the transmission source address as the address C3. The output Leave request reaches the L2 switch 400.

  [Step S85] The L2 switch 400 receives the Leave request from the client 53. Then, the L2 switch 400 deletes the registration of the client 53 for the address M1 from the multicast table.

[Step S86] The L2 switch 400 transmits the latest transfer information to the audience rating server 600 because the number of transfer destinations is reduced by the deletion process in step S85.
[Step S87] When the number of transfer destinations for the address M1 becomes zero as a result of the deletion process in step S85, the L2 switch 400 sends a Leave request with the destination address as the address M1 and the source address as the address R4 to the router 100. To do.

  [Step S88] The router 100 receives the Leave request from the L2 switch 400. Then, the router 100 deletes the registration of the L2 switch 400 for the address M1 from the multicast table.

  [Step S89] When the number of transfer destinations for the address M1 becomes 0 by the deletion process in step S88, the router 100 transmits a Leave request with the destination address as the address M1 and the source address as the address R1 to the router 200. .

  [Step S90] The router 200 receives the Leave request from the router 100. Then, the router 200 deletes the registration of the router 100 for the address M1 from the multicast table.

  In this way, the client 53 outputs a Join request at the start of viewing. Then, the L2 switch 400 registers the client 53 in the multicast table, the router 100 registers the L2 switch 400 in the multicast table, and the router 200 registers the router 100 in the multicast table. As a result, the multicast packet is relayed from the distribution server 41 to the router 200, the router 100, the L2 switch 400, and the client 53. Here, the L2 switch 400 transmits the transfer information to the audience rating server 600 when the client 53 is registered.

  By using such a content distribution system, the distribution servers 41 and 42 and the clients 51, 52, 53, and 54 need only be compatible with general multicast communication protocols, and are equipped with dedicated hardware and software. There is no need to do. For this reason, it is possible to easily realize the viewing state of the content. In particular, since the audience rating server 600 accumulates information indicating the viewing status of the entire content distribution system in time series, the administrator can appropriately consider the facility enhancement and charging method. As a result, a more stable content distribution system can be realized.

[Second Embodiment]
Next, a second embodiment will be described. The first embodiment is a system that can grasp the instantaneous number of viewers, but the second embodiment is a system that can further grasp the total number of viewers and the total viewing time within a predetermined period. is there. Differences from the first embodiment will be mainly described, and description of similar matters will be omitted.

  The system configuration of the second embodiment is the same as that of the first embodiment shown in FIG. However, some of the processing functions provided in the router, the L2 switch, and the audience rating server are different from those in the first embodiment. In the following description, it is assumed that the router 100a is a communication device corresponding to the router 100 described above, and the audience rating server 600a is a computer corresponding to the audience rating server 600 described above.

  FIG. 15 is a block diagram illustrating functions of the router according to the second embodiment. The router 100a includes a routing information storage unit 110, a multicast information storage unit 120, a period transfer information storage unit 130a, an input control unit 140, a route determination unit 150, a multicast processing unit 160, a period transfer status monitoring unit 170a, and an output control unit 180. Have.

  The functions of the routing information storage unit 110, the multicast information storage unit 120, the input control unit 140, the route determination unit 150, the multicast processing unit 160, and the output control unit 180 are the same as those in the first embodiment.

  In the period transfer information storage unit 130a, for each multicast address, transfer information indicating the current number of transfer destinations, the total number of transfer destinations and the total transfer time since the transfer information was last transmitted to the audience rating server 600 is stored. Stored. The number of transfer destinations and the total number of transfer destinations are calculated excluding other communication devices having a multicast packet transfer control function.

  The period transfer status monitoring unit 170 a monitors the multicast table 121 stored in the multicast information storage unit 120. Here, when a transfer destination is newly added, the period transfer status monitoring unit 170a recalculates the number of transfer destinations and adds the total number of transfer destinations by the increase in the number of transfer destinations, and the period transfer information storage unit The transfer information stored in 130a is updated.

  Further, when the transfer destination is deleted, the period transfer status monitoring unit 170a recalculates the number of transfer destinations and updates the transfer information stored in the period transfer information storage unit 130a. Further, when the transfer destination update time becomes new due to continuous reception of the Join request, the period transfer status monitoring unit 170a adds the total transfer time by the elapsed time from the previous update time, and the period transfer information storage unit 130a. The transfer information stored in is updated.

  Further, in response to the report request transmitted by the audience rating server 600a, the period transfer status monitoring unit 170a acquires the current transfer information from the period transfer information storage unit 130a, and generates a packet addressed to the audience rating server 600a. At this time, the period transfer status monitoring unit 170a initializes the total number of transfer destinations and the total transfer time of the transfer information stored in the period transfer information storage unit 130a to zero.

  Note that, unlike the first embodiment, the period transfer status monitoring unit 170a selects a method for transmitting transfer information to the audience rating server 600 every time the number of transfer destinations increases or decreases as a transfer information transmission method. Can not.

  FIG. 16 is a block diagram illustrating functions of the audience rating server according to the second embodiment. The audience rating server 600a includes a period transfer information collection unit 610a, a period transfer information storage unit 620a, a period viewing status totaling unit 630a, and a period viewing information storage unit 640a.

  The period transfer information collection unit 610a collects transfer information at a predetermined time interval from a communication apparatus having a multicast packet transfer control function. Then, the period transfer information collection unit 610a sequentially stores the transfer information acquired from each communication device in the period transfer information storage unit 620a. Note that the administrator can select either UDP or TCP as the communication protocol.

  Based on the transfer information stored in the period transfer information storage unit 620a, the period viewing status totaling unit 630a determines the current number of received clients, the total number of clients and the total reception time since the previous aggregation is performed, as a multicast address. Aggregate every time. For example, the period viewing status totaling unit 630a counts every 10 minutes. Then, the period viewing status totaling unit 630a associates the total result with the total time, and stores it in the period viewing information storage unit 640a as viewing information.

  FIG. 17 illustrates a data structure of the transfer information table according to the second embodiment. The transfer information table 132 shown in FIG. 17 is stored in the period transfer information storage unit 130a of the router 100a. The transfer information table 132 includes an item indicating a multicast address, an item indicating the number of transfer destinations, an item indicating the total number of transfer destinations, and an item indicating the total transfer time. Information arranged in the horizontal direction of each item is associated with each other.

  In the item of multicast address, a multicast address for identifying a video is set. In the item of the transfer destination number, the current transfer destination number of the multicast packet is set. In the item of the total number of transfer destinations, the total number of transfer destinations measured from the start of each counting period is set. In the item of total transfer time, a total value of transfer continuation times of multicast packets to each transfer destination measured from the start of each counting period is set. Information stored in the transfer information table 132 is appropriately updated by the period transfer status monitoring unit 170a.

  FIG. 18 illustrates a data structure of the viewing information table according to the second embodiment. The viewing information table 642 shown in FIG. 18 is stored in the period viewing information storage unit 640a of the audience rating server 600a. The viewing information table 642 includes an item indicating the date, an item indicating the multicast address, an item indicating the number of views, an item indicating the total number of views, and an item indicating the total teacher long time. Information arranged in the horizontal direction of each item is associated with each other.

  In the date and time item, the date and time when the period viewing status totaling unit 630a performs the totaling process is set. In the item of multicast address, a multicast address for identifying a video is set. The total number of transfer destinations in all communication devices is set in the viewing number item. In the total viewing number item, a total value of the total number of transfer destinations in all communication apparatuses is set. In the item of total viewing time, a total value of total transfer time in all communication devices is set. Information stored in the viewing information table 642 is periodically added by the period viewing status totaling unit 630a.

The overall flow of processing executed in the system having the above-described configuration and data structure is the same as that of the first embodiment shown in FIGS.
By using such a content distribution system, the same effect as the content distribution system according to the first embodiment can be obtained. Furthermore, by using the content distribution system according to the second embodiment, information on the total number of viewings and the total viewing time for each predetermined time interval is accumulated in time series in the audience rating server 600a. For this reason, even when there is a user who frequently switches the content to be viewed, the administrator can grasp an accurate viewing situation. Therefore, it becomes possible to construct a more realistic content distribution system.

  In the above-described embodiment, each communication device excludes other communication devices and calculates the number of transfer destinations, and the audience rating server specifies the number of views by totaling the number of transfer destinations. On the other hand, each communication device may calculate the number of transfer destinations without excluding other communication devices, and the audience rating server may appropriately specify the number of views in consideration of the connection relationship between the communication devices. . The administrator preferably selects which method to use in consideration of the load that the above processing places on the communication device and the audience rating server.

  The viewing situation monitoring method, viewing situation monitoring apparatus, viewing situation monitoring program, and viewing situation monitoring system according to the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and each unit The configuration of can be replaced with any configuration having the same function. Moreover, other arbitrary structures and processes may be added to the present invention. Further, the present invention may be a combination of any two or more configurations (features) of the above-described embodiments.

  The above processing functions can be realized by a computer. In that case, a program describing the processing contents of the functions that the server should have is provided. By executing the program on a computer, the above processing functions are realized on the computer. The program describing the processing contents can be recorded on a computer-readable recording medium. Examples of the computer-readable recording medium include a magnetic recording device, an optical disk, a magneto-optical recording medium, and a semiconductor memory. Examples of the magnetic recording device include a hard disk device (HDD), a flexible disk (FD), and a magnetic tape (MT). Optical disks include DVD (Digital Versatile Disc), DVD-RAM, CD-ROM (Compact Disc-Read Only Memory), CD-R (Recordable) / RW (ReWritable), and the like. Magneto-optical recording media include MO (Magneto-Optical disk).

  When distributing the program, for example, a portable recording medium such as a DVD or a CD-ROM in which the program is recorded is sold. It is also possible to store the program in a storage device of a server computer and transfer the program from the server computer to another computer via a network.

  The computer that executes the program stores, for example, the program recorded on the portable recording medium or the program transferred from the server computer in its own storage device. Then, the computer reads the program from its own storage device and executes processing according to the program. The computer can also read the program directly from the portable recording medium and execute processing according to the program. In addition, each time the program is transferred from the server computer, the computer can sequentially execute processing according to the received program.

The main technical features of the embodiment described above are as follows.
(Supplementary Note 1) Monitoring the viewing status of the content executed in a communication device located on a route from a distribution device that generates a packet corresponding to the content distributed by multicast to one or more reproduction devices that reproduce the content In the viewing status monitoring method,
When a transfer request designating a multicast address that identifies the content is received, a source of the transfer request is transferred to a transfer table that associates the multicast address with a transfer destination address that identifies a transfer destination device to which the packet is to be transferred. A management step of registering as the forwarding destination device and maintaining registration of the forwarding table while continuously receiving the forwarding request from the forwarding destination device;
Monitor the forwarding table, calculate the current forwarding destination number for each multicast address, manage forwarding information indicating the forwarding destination number, and viewing information indicating the number of playback devices receiving the packet Monitoring step of continuously transmitting to the management device via the network;
A viewing situation monitoring method characterized by comprising:

  (Supplementary Note 2) In the monitoring step, the communication device is configured such that when another communication device capable of controlling the forwarding destination of the packet having the multicast address is registered in the forwarding table as the forwarding destination device, 2. The viewing status monitoring method according to claim 1, wherein the number of transfer destinations is calculated excluding other communication devices.

  (Supplementary Note 3) In the monitoring step, the communication device further calculates a total transfer time for each multicast address based on an elapsed time in which each of the transfer destination addresses is registered in the transfer table, and the transfer The viewing status monitoring method according to claim 1, wherein the transfer information is transmitted to the management apparatus including the total transfer time in the information.

  (Supplementary note 4) In the monitoring step, the communication device transmits the transfer information to the management device in response to a report request transmitted by the management device at a predetermined time interval. Item 1. The viewing status monitoring method according to Item 1.

  (Supplementary Note 5) The viewing state monitoring method according to claim 1, wherein, in the monitoring step, the communication device transmits the transfer information to the management device every time the transfer destination number changes. .

(Additional remark 6) In the viewing condition monitoring apparatus which is located on the path | route from the delivery apparatus which produces | generates the packet corresponding to the content delivered by multicast to one or more reproduction | regeneration apparatuses which reproduce | regenerate the said content, and monitors the viewing condition of the said content ,
A forwarding table associating a multicast address for identifying the content with a forwarding destination address for identifying a forwarding destination device to which the packet is to be forwarded;
Upon receiving the transfer request designating the multicast address, while registering the transfer request source as the transfer destination device in the transfer table, while continuously receiving the transfer request from the transfer destination device, Forwarding table management means for maintaining registration of the forwarding table;
Monitor the forwarding table, calculate the current forwarding destination number for each multicast address, manage forwarding information indicating the forwarding destination number, and viewing information indicating the number of playback devices receiving the packet Transfer status monitoring means for continuously transmitting to the management device via the network;
A viewing situation monitoring apparatus comprising:

(Additional remark 7) The process which monitors the viewing condition of the said content is performed in the computer located on the path | route from the delivery apparatus which produces | generates the packet corresponding to the content delivered by multicast to one or more reproduction | regeneration apparatuses which reproduce | regenerate the said content In the viewing situation monitoring program for causing the computer to
Transfer table storage means for storing a transfer table that associates a multicast address for identifying the content with a transfer destination address for identifying a transfer destination device to which the packet is to be transferred;
Upon receiving the transfer request designating the multicast address, while registering the transfer request source as the transfer destination device in the transfer table, while continuously receiving the transfer request from the transfer destination device, Transfer table management means for maintaining registration of the transfer table;
Monitor the forwarding table, calculate the current forwarding destination number for each multicast address, manage forwarding information indicating the forwarding destination number, and viewing information indicating the number of playback devices receiving the packet Transfer status monitoring means for continuously transmitting to the management device via the network,
A viewing situation monitoring program characterized by functioning as

(Supplementary Note 8) In a viewing status monitoring system that monitors the viewing status of the content on a route from a distribution device that generates a packet corresponding to the content distributed by multicast to one or more playback devices that reproduce the content,
A forwarding table associating a multicast address for identifying the content with a forwarding destination address for identifying a forwarding destination device to which the packet is to be forwarded;
Upon receiving the transfer request designating the multicast address, while registering the transfer request source as the transfer destination device in the transfer table, while continuously receiving the transfer request from the transfer destination device, Forwarding table management means for maintaining registration of the forwarding table;
A transfer status monitoring means for monitoring the transfer table and calculating a current transfer destination number for each multicast address;
A plurality of communication devices comprising:
Viewing information storage means for storing viewing information indicating the number of the playback devices receiving the packet in time series for each multicast address;
Transfer information collecting means for continuously collecting transfer information indicating the number of transfer destinations from the plurality of communication devices via a network;
Viewing information totaling means for generating the viewing information by counting the transfer information collected by the transfer information collecting means, storing the generated viewing information in the viewing information storage means in association with the counting time;
A viewing information management device comprising:
A viewing situation monitoring system comprising:

It is a figure which shows the outline | summary of this Embodiment. It is a figure which shows the system configuration | structure of this Embodiment. It is a figure which shows the hardware constitutions of an audience rating server. It is a block diagram which shows the function of the router of 1st Embodiment. It is a block diagram which shows the function of the audience rating server of 1st Embodiment. It is a figure which shows the data structure of a video name table. It is a figure which shows the data structure of a routing table. It is a figure which shows the data structure of a multicast table. It is a figure which shows the data structure of the transfer information table of 1st Embodiment. It is a figure which shows the data structure of the viewing-and-listening information table of 1st Embodiment. It is a 1st sequence diagram which shows the flow of multicast delivery. It is a 2nd sequence diagram which shows the flow of multicast delivery. It is a 3rd sequence diagram which shows the flow of multicast delivery. It is a 4th sequence diagram which shows the flow of multicast delivery. It is a block diagram which shows the function of the router of 2nd Embodiment. It is a block diagram which shows the function of the audience rating server of 2nd Embodiment. It is a figure which shows the data structure of the transfer information table of 2nd Embodiment. It is a figure which shows the data structure of the viewing-and-listening information table of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication apparatus 1a Transfer table 1b Transfer table management means 1c Packet transfer means 2 Management apparatus 2a Viewing information storage means 2b Transfer information collection means 2c Viewing status totaling means 3a, 3b Distribution apparatus 4a, 4b, 4c Playback apparatus

Claims (5)

A viewing status monitoring method for monitoring the viewing status of the content executed in a communication device located on a path from a distribution device that generates a packet corresponding to the content distributed by multicast to a plurality of playback devices capable of reproducing the content In
Upon receiving a transfer request specifying a multicast address identifying the contents, the transfer source of the request, a plurality association enables the transfer destination address identifying the destination device to forward the packet to the multicast address to Do forwarding table, while with registered as the transfer destination device, and continuously receives the transfer request from the transfer destination device, and a management step of maintaining the register of the transfer table,
Monitor the forwarding table to calculate the current number of forwarding destinations for each multicast address, and based on the elapsed time each forwarding destination address is registered in the forwarding table, the packet to each forwarding destination the total transfer time which is the sum of the transfer time of the calculations for each of the multicast address, the transfer information which the transfer destination number and indicating the total transfer time, to the management apparatus that manages viewing state by previous SL plurality of playback devices A monitoring step for continuous transmission over the network;
A viewing situation monitoring method characterized by comprising:   In the monitoring step, the communication device, when another communication device capable of controlling the forwarding destination of the packet having the multicast address is registered in the forwarding table as the forwarding destination device, The viewing status monitoring method according to claim 1, wherein the number of transfer destinations is calculated by excluding the number of destinations.   In a viewing status monitoring device that is located on a route from a distribution device that generates a packet corresponding to content distributed by multicast to a plurality of playback devices capable of reproducing the content, and that monitors the viewing status of the content,
  A forwarding table capable of associating a plurality of forwarding destination addresses for identifying forwarding destination devices to which the packet should be forwarded, with a multicast address for identifying the content;
  Upon receiving the transfer request designating the multicast address, while registering the transfer request source as the transfer destination device in the transfer table, while continuously receiving the transfer request from the transfer destination device, Forwarding table management means for maintaining registration of the forwarding table;
  Monitor the forwarding table to calculate the current number of forwarding destinations for each multicast address, and based on the elapsed time each forwarding destination address is registered in the forwarding table, the packet to each forwarding destination The total transfer time is calculated for each multicast address, and the transfer information indicating the number of transfer destinations and the total transfer time is sent to the management device that manages the viewing status of the plurality of playback devices. A transfer status monitoring means for continuously transmitting via the network;
  A viewing situation monitoring apparatus comprising:   Viewing status monitoring for causing a computer located on a route from a distribution device that generates a packet corresponding to content distributed by multicast to a plurality of playback devices capable of reproducing the content to execute processing for monitoring the viewing status of the content In the program, the computer is
  Transfer table storage means for storing a transfer table capable of associating a plurality of transfer destination addresses for identifying transfer destination devices to which the packet is transferred with respect to a multicast address for identifying the content;
  Upon receiving the transfer request designating the multicast address, while registering the transfer request source as the transfer destination device in the transfer table, while continuously receiving the transfer request from the transfer destination device, Transfer table management means for maintaining registration of the transfer table;
  Monitor the forwarding table to calculate the current number of forwarding destinations for each multicast address, and based on the elapsed time each forwarding destination address is registered in the forwarding table, the packet to each forwarding destination The total transfer time is calculated for each multicast address, and the transfer information indicating the number of transfer destinations and the total transfer time is sent to the management device that manages the viewing status of the plurality of playback devices. Transfer status monitoring means for continuous transmission over the network,
  A viewing situation monitoring program characterized by functioning as   In a viewing status monitoring system that monitors the viewing status of the content on a route from a distribution device that generates a packet corresponding to the content distributed by multicast to a plurality of playback devices capable of reproducing the content,
  A forwarding table capable of associating a plurality of forwarding destination addresses for identifying forwarding destination devices to which the packet should be forwarded, with a multicast address for identifying the content;
  Upon receiving the transfer request designating the multicast address, while registering the transfer request source as the transfer destination device in the transfer table, while continuously receiving the transfer request from the transfer destination device, Forwarding table management means for maintaining registration of the forwarding table;
  Monitor the forwarding table to calculate the current number of forwarding destinations for each multicast address, and based on the elapsed time each forwarding destination address is registered in the forwarding table, the packet to each forwarding destination Transfer status monitoring means for calculating the total transfer time for each multicast address,
  A plurality of communication devices comprising:
  Viewing information storage means for storing, in chronological order, viewing information indicating the number of playback devices receiving the packet and the total reception time by the plurality of playback devices for each multicast address;
  Transfer information collecting means for continuously collecting transfer information indicating the number of transfer destinations and the total transfer time from the plurality of communication devices via a network;
  Viewing information totaling means for generating the viewing information by counting the transfer information collected by the transfer information collecting means, storing the generated viewing information in the viewing information storage means in association with the counting time;
  A viewing information management device comprising:
  A viewing situation monitoring system comprising:

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