Ip broadcasting system and multi-cast group management device for ip broadcasting

The present invention relates to a broadcasting service using the Internet Protocol (IP), and relates to an IP broadcasting system technology for providing a broadcasting communication fusion service using a multicast technology.

Multicast communication is a technology that copies IP datagrams with a multicast router and sends them to members belonging to a multicast group, and has already been developed in a wide range. The so-called multicast technology is based on the standard document RFC (Request for Comments) 1112, 2236, 3376 created by the IETF (Internet Engineering Task Force) and published by the IAB (Internet Architecture Board), and performs multicast communication. A technology for managing and notifying information about members in a group. This technology is also called IGMP (Internet Group Management Protocol) in the above RFC and is applied to multicast routers. Multicast communication is executed by the multicast router to which these technologies are applied. In addition, MLD (Multicast Listener Discovery) compliant with RFC2710,3810 is also used. This applies to multicast communication that supports IPv6.

A feature of multicast communication is that only one multicast IP datagram needs to be sent at the time of transmission. Specifically, the multicast IP datagram is automatically copied by the multicast router to which IGMP is applied and sent to the network belonging to the member of the multicast group. Multicast IP datagrams are identified by a single address value called a multicast address.

In recent years, this multicast technology has been applied to IPTV (Internet Protocol TV) broadcasting services. In the broadcasting service, a multicast address is assigned to the broadcasting channel of IPTV, and it is distributed to the multicast group by a network consisting of multicast routers. On the other hand, when an IP broadcasting terminal that is a viewer of an IPTV broadcasting channel wants to receive an IPTV broadcasting, it can receive the IPTV broadcasting by joining this multicast group and becoming a member of the multicast group. At this time, the IP broadcasting terminal needs to know the IP information such as the multicast address information in advance. The management and notification of information about such multicast members is performed by IGMP and MLD.

These multicast technologies are used for services that require a reduction in the amount of data on the network when there are many users who receive the same data, such as IPTV broadcasting services. It is also used for IP packet delivery, which requires reducing the setting load of individual destination IP addresses in services where the number of receiving users increases or decreases.

However, in the actual IPTV broadcasting service, the IP broadcasting user selects the IPTV broadcasting channel to be viewed from the IPTV broadcasting channel name and channel number provided by the broadcasting company. Therefore, the IP broadcasting terminal needs to determine the multicast address from this channel number and acquire the IP broadcasting data from the network. However, if the number of IP broadcasting programs provided, the number of IP broadcasting channels, and the number of IP broadcasting terminals themselves increase as the number of users increases, the IP broadcasting system will not be able to manage and acquire all multicast addresses on the network. It will be extremely difficult.

On the other hand, in Patent Document 1, when a broadcast digital service is provided, modified EPG information including IP information for each broadcast channel is generated in EPG (Electronic Program Guide) information including information on the content and type of the program. It discloses a method of multiplexing into a broadcast stream and transmitting it to a user's terminal.

<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2006-174453</text></patcit>

<p> Since the conventional IP broadcasting server does not have the function of notifying the user of the TV broadcasting channel information and the multicast address information, it is not possible to efficiently notify the multicast information when a new IP broadcasting terminal is added. Further, when the EPG information is used, since the EPG information is added to the broadcast stream, the EPG information of the program can be received only when the broadcast stream is being received. Therefore, the user has no means to know the EPG information and the IP information contained in the EPG information just by adding a new broadcast program by the broadcaster.</p><p> An object of the present invention is an IP broadcasting system for eliminating the need for a broadcasting company to set IP broadcasting channel information and a multicast address and reducing the load of notifying an IP broadcasting terminal of a multicast address, and IP broadcasting thereof. To provide a multicast group management device for.</p>

<p> In order to achieve the above object, the present invention provides an IP broadcasting system that provides an IP broadcasting service via an IP multicast network, an IP broadcasting server capable of distributing video data by assigning a multicast group identifier, and an IP broadcasting channel. It is composed of an IP broadcasting terminal capable of transmitting an identifier and an IP broadcasting multicast group management device having a storage unit that holds correspondence information between the multicast group identifier and the IP broadcasting channel identifier. Then, the IP broadcasting terminal sends a query message including the requested IP broadcasting channel identifier to the IP broadcasting multicast group management device, and the IP broadcasting channel identifier included in the query message transmitted from the IP broadcasting multicast group management device. It is configured to include a transmission / reception unit that receives a response message including a multicast group identifier corresponding to the above and transmits a video reception request message using the received multicast group identifier.</p><p> Further, in the present invention, a set-top box for connecting an IP broadcasting terminal to an IP multicast network to which an IP broadcasting server capable of distributing video data by assigning a multicast group identifier is connected is provided from the connected IP broadcasting terminal. When a transmitter that sends a video distribution request message in advance based on user information, a receiver that receives video data transmitted based on the video distribution request message, and a video reception request message from an IP broadcasting terminal are received, the video It consists of a processing unit that controls the transmission of video data corresponding to the reception request message to the IP broadcasting terminal.</p><p> As the multicast group identifier, a multicast address or a combination of a multicast address and a source address is preferably used. These multicast addresses and source addresses that serve as multicast group identifiers are those specified in the above-mentioned IGMP and MLD.</p>

<p> According to the present invention, in an IP broadcasting system that provides an IP broadcasting service via an IP network, the IP broadcasting channel number and the multicast address can be efficiently set by linking the multicast group management device for IP broadcasting and the IP broadcasting terminal. It becomes possible to manage.</p><p> Moreover, even if the number of IPTV broadcasting channels increases, the IP broadcasting terminal can acquire only the multicast address for the required IP broadcasting channel number. Therefore, the load associated with changing the number of IPTV broadcasting channels is reduced.</p><p> Furthermore, even if the number of IP broadcasting terminals increases, it is possible to acquire a multicast address without accessing all IP broadcasting servers, so that the load associated with changing the number of IP broadcasting terminals is reduced.</p><p> Furthermore, by linking the IP broadcasting terminal and the multicast group management device for IP broadcasting, the load of setting the multicast address of the broadcasting company on the IP broadcasting terminal is reduced.</p><p> Furthermore, preferably, the set-top box receives the video data in advance, so that the time required for changing the IP broadcasting channel is shortened. Therefore, it is possible to provide a comfortable service to the user.</p>

Hereinafter, embodiments of the present invention will be described as an example of the case where IPTV broadcasting is used as an application. However, it goes without saying that it is not necessarily limited to this application. Further, a case where a multicast address is used as the multicast group identifier is illustrated, but the present invention is not limited to this, as described above.

FIG. 1 is a diagram showing a first embodiment of an IP broadcasting system for providing the IP broadcasting service of the present invention.

First, the network configuration will be described. The IP broadcasting service is provided between the IP broadcasting server 20 and the IP broadcasting terminal 30 via the multicast network 40. The multicast network 40 is composed of a multicast router (not shown) capable of multicasting an IP packet having a multicast address as a multicast group identifier, and is transmitted based on the multicast address. Here, the number of IP broadcasting terminals 30 may be plural. The set-top box 80 is usually installed in a house and has a media conversion function and the like. For example, in the case of an optical access network, an ONU (Optical Network Unit) converts an optical signal into an electrical signal. Other functions will be described later.

The IP broadcasting multicast group management device 10 of this embodiment manages the IP broadcasting channel identifier-multicast address biting table 11 that holds the correspondence between the broadcasting channel identifier and the multicast address, and the multicast address list that can be used in the network. It has a multicast address pool table 12 for the purpose and an IP broadcast channel management table 13 for managing a list of IP broadcast channel identifications that can be used in the network.

Here, in the IP broadcasting channel identifier-multicast address biting table 11, the IP broadcasting channel identifier and the multicast address set in the IP broadcasting server are preset. In the multicast address pool table 12, the multicast addresses that can be used in the network are set in the initial state. Further, in the IP broadcasting channel management table 13, IP broadcasting channel identifiers that can be broadcast on the network are preset.

The IP broadcasting multicast group management device 10 further includes an I / O interface 14 that sends and receives messages from the IP broadcasting terminal 30, a CPU (Central Processing Unit) 15 that functions as a processing unit that processes these messages, and a program. It consists of 16 retained memory.

This CPU 15 extracts the broadcast channel ID (identifier) from the message 73 received from the IP broadcasting terminal 30 or the message 72 received from the IP broadcasting portal, and follows the program stored in the memory 16 from the multicast address binding table 11. , Determine the multicast address corresponding to the IP broadcast channel identifier. After that, the CPU 15 generates a message 74 including the determined multicast address and outputs it to the I / O interface 14 for transmission to the IP broadcasting terminal.

In the IP broadcasting multicast group management device 10, the CPU 15 receives a multicast address allocation request for the IP broadcasting channel identifier from the IP broadcasting server 20, and multicasts based on the IP broadcasting channel management table 13 and the multicast address pool table 12. Determine the address and notify the IP broadcasting server 20. The CPU 35 updates the IP broadcast channel identifier-multicast address biting table 11 according to the multicast address determined as the IP broadcast channel identifier.

The IP broadcasting terminal 30 of this embodiment functions as a transmission / reception unit, and has a GE interface 31 that receives IP packets, a packet processing unit 32 that selects and processes IP packets to be received, and an MPEG (Moving) that processes video from the packets. Picture Expert Group) A processing unit 33, a CPU 35 that controls these and processes messages, a memory 36 that holds a program executed by the CPU 35, and a cache memory 34 that explains its function later are provided. The cache memory 34 and the memory 36 form a storage unit of the IP broadcasting terminal 30. Needless to say, the packet processing unit 32 and the MPEG processing unit 33 may be configured not only by the hardware configuration but also by the software processing. In that case, these software processings are also executed by the CPU 35. ..

In the IP broadcasting terminal 30, the first method, the CPU 35, creates a message 73 including an IP broadcasting channel identifier from the user's IP broadcasting channel selection request 70, for example, an input from a remote control, and the IP broadcasting multicast group management device 10 Send to. It is also possible to access the IP broadcasting portal 50 by the second method, HTTP, etc., create a message 72 including the IP broadcasting channel identifier, and send it to the IP broadcasting multicast group management device 10. In the following examples, the first method will be used, but the present invention is not limited to this.

After that, the CPU 35 determines the multicast address information from the message 74 received from the IP broadcasting multicast group management device 10, and notifies the packet processing unit 32 of the multicast address information. The packet processing unit 32 transmits the video reception request message 75 to the multicast group according to the notified multicast address, and after the reception becomes possible, selects and processes the IP packet. For example, RFC (Request for Comments) 2236 IGMPv2 Join message can be used as a join message.

In the IP broadcasting terminal 30, the CPU 35 updates the cache memory 34 according to the multicast address received from the IP broadcasting multicast group management device 10 and the IP broadcasting channel identifier. From the next time, the response speed of IP broadcast channel selection will be improved by searching the cache memory.

FIG. 2 shows a flowchart of the multicast address resolution operation executed by the IP broadcasting terminal 30 of this embodiment. Here, an example of an IP broadcasting terminal in an IP broadcasting system that provides the IP broadcasting service of this embodiment will be described. That is, the flow in which the IP broadcasting terminal 30 selects and receives an IP packet of broadcast video from a multicast network based on the IP broadcasting channel identifier will be described. Further, this flowchart is executed by, for example, the CPU 35 of the IP broadcasting terminal 30.

First, the IP broadcasting terminal 30 determines whether or not it has received the IP broadcasting channel identifier including the IP broadcasting channel information to be viewed by the user (step 301). Next, when the IP broadcast channel identifier is received, the cache memory is referred to to search for the multicast address (MCA: Multicast Address) corresponding to the IP broadcast channel identifier (step 302).

In the cache memory 34, for example, as shown in FIG. 4, an IP broadcast channel identifier including a list of the IP broadcast channel identifier 11a and the multicast address 11b-IP broadcast channel identifier-multicast address binding table 11 is stored. .. In this embodiment, for example, the IP broadcast channel identifier is "Ch1@ISP-A.COM" and the multicast address is "239.255.255.10".

In step 302, if there is no multicast address that matches the IP broadcast channel identifier in the IP broadcast channel identifier-IP broadcast channel identifier-multicast address binding table 11, a multicast address query message containing the IP broadcast channel identifier is displayed. Send (step 303).

In this embodiment, the query message 61 includes, for example, an IP broadcast channel identifier, as shown in FIG. 6 (a). In addition, SIP URL (Session Initiation Protocol Uniform Resource Locator), XML (Extensible Markup Language), etc. may be used as the message format. The IP broadcast channel identifier may be any information that identifies the IP broadcast channel.

Next, it is determined whether or not a multicast address response message including the transmitted IP broadcast channel identifier and the corresponding multicast address has been received (step 304). When a multicast address response message is received, the IP broadcast channel identifier and multicast address are registered, and the IP broadcast channel identifier-multicast address binding table is updated (step 305). In this embodiment, the response message 62 includes, for example, the IP broadcast channel identifier and the corresponding multicast address, as shown in FIG. 6 (b). In addition, SIP URL, XML, etc. may be used as the message format. Further, the multicast address may be IPv4 or IPv6.

Next, when a multicast address response message is received, or in step 302, there is a multicast address that matches the IP broadcast channel identifier in the IP broadcast channel identifier-multicast address binding table 11 stored in the cache memory. If so, send a multicast group join message to multicast network 40 (step 306). As a result, it is possible to receive an IP packet that transmits the IPTV broadcast channel data indicated by the IP broadcast channel identifier. The IP broadcasting terminal does not have to be provided with the IP broadcasting channel identifier-multicast address binding table 11. In this case, for example, in the flowchart of this embodiment, steps 302 and 305 are not always necessary.

As a result of the above, the IP broadcasting terminal 30 can receive the IP packet corresponding to the IP broadcasting channel identifier and reproduce the IP broadcasting channel.

FIG. 3 shows an example of a flowchart of the multicast address resolution operation executed by the multicast group management device 10 for IP broadcasting required for the IP broadcasting system of the first embodiment. That is, the operation flow in which the multicast group management device 10 for IP broadcasting responds to an inquiry from the IP broadcasting terminal 30 and returns a multicast address will be described. In this embodiment, this flowchart is executed by, for example, CPU 15 of the multicast group management device 10 for IP broadcasting.

First, the IP broadcasting multicast group management device 10 determines whether or not a multicast address query message including the IP broadcasting channel identifier has been received ( step 101). When a multicast address query message is received, the IP broadcast channel identifier is extracted from the multicast address query message, and the IP broadcast channel management table 13 is referred to to determine whether or not the IP broadcast channel identifier exists (step 102). ).

As shown in FIG. 5, for example, the IP broadcasting channel management table 13 stores information indicating the situation corresponding to the IP broadcasting channel identifier. In this embodiment, the IP broadcast channel identifier 13a indicates "Ch1@ISP-A.COM", and the corresponding situation 13b indicates that it is "on air". The IP broadcast channel management table can also include other information items.

Next, in step 102, if the IP broadcast channel identifier exists, the corresponding multicast address is searched for by referring to the IP broadcast channel identifier-multicast address binding table 11 (step 103).

In this embodiment, the IP broadcast channel identifier-multicast address binding table 11 includes a list of multicast addresses 11b corresponding to the IP broadcast channel identifier 11a, as shown in FIG. The IP broadcasting channel identifier-multicast address binding table is preset in the IP broadcasting multicast group management device 10. For example, the IP broadcast channel identifier 11a indicates that it is "Ch1@ISP-A.COM", and the corresponding multicast address 11b is "239.255.255.10".

In step 103, if the corresponding multicast address 11b exists, the CPU 15 generates a multicast address response message including the multicast address 11b and sends it to the IP broadcasting terminal (step 104). As a result, the IP broadcasting terminal 30 can select and receive the IP packet based on the multicast address 11b.

Next, FIG. 7 shows a flowchart of an operation of assigning a multicast address executed by the multicast group management device 10 for IP broadcasting that manages the IP broadcasting service of the present invention. In this embodiment, the operation flow in which the multicast group management device 10 for IP broadcasting responds to the multicast address allocation request from the IP broadcasting server 30 and allocates the multicast address will be described.

First, the IP broadcasting multicast group management device 10 determines whether or not a multicast address request message including the IP broadcasting channel identifier has been received from the IP broadcasting server 30 (step 201). When a multicast address request message is received, the IP broadcast channel identifier is extracted from the multicast address request message, and the multicast address pool table 12 is referred to to determine whether or not an assignable multicast address exists (step). 102,103).

The multicast address pool table 12 stores information 12b indicating the allocation status in correspondence with the multicast address 12a, for example, as shown in an embodiment in FIG. In this embodiment, the multicast address 12a indicates "224.0.0.0", and the allocation status 12b indicates that the allocation is "possible". The multicast address pool table 12 can also include other information items.

Next, in step 203, if an assignable multicast address exists, the multicast address / allocation message including the assignable multicast address is generated by referring to the multicast address pool table 12 and sent to the IP broadcasting server. (Step 204). Also, in the multicast address pool table 12, change the allocation status to "allocated". Also, in the IP broadcast channel identifier-multicast address binding table 11, the IP broadcast channel identifier information and the multicast information data are updated.

As a result, the IP broadcasting server 20 transmits an IP packet based on the assigned multicast address. As a result, the multicast group management device 10 for IP broadcasting can centrally manage the multicast address and can quickly respond to inquiries from the IP broadcasting terminal.

FIG. 9 is a diagram showing a message sequence for explaining the entire IP broadcasting system in the first embodiment described above. At time t0. The multicast address request message transmitted from the IP broadcasting server 20 is received by the multicast group management device 10 for IP broadcasting (step 141). As shown in FIG. 7, the multicast group management device 10 for IP broadcasting determines the multicast address with reference to the multicast address pool table 12 (step 142), and sends a multicast address allocation message to the IP broadcasting server 30. (Step 143). As a result, the IP broadcasting server 20 transmits an IP packet including the assigned multicast address and starts IP broadcasting. At this point, the IP packet has been sent to the multicast network 40, but has not been received by the IP broadcasting terminal 30.

Next, in order for the user to watch the IP broadcast, a signal including the IP broadcast channel identifier is input or transmitted to the IP broadcast terminal 30 using the IP broadcast channel selection request 70 (step 144). As shown in FIG. 2, the IP broadcasting terminal 30 transmits a multicast address / query message including the IP broadcasting channel identifier to the multicast group management device 10 for IP broadcasting (step 145).

Next, as shown in FIG. 3, the multicast group management device 10 for IP broadcasting determines the corresponding multicast address by referring to the received IP broadcasting channel identifier and the IP broadcasting channel identifier-multicast address binding table 11. Then, a multicast address response message including the determined multicast address is transmitted to the IP broadcasting terminal 30 (step 147).

The IP broadcasting terminal 30 analyzes the received multicast address / response message, determines the multicast address to be received, sends a multicast group participation message to the multicast router, and after the IP broadcasting terminal 30 becomes receivable, Select and receive the IP packet (step 148). As a result, the IP broadcasting terminal 30 can receive the broadcast video IP packet, and the user can watch the IP broadcasting.

FIG. 10 shows a flowchart of an operation for canceling the multicast address allocation executed by the multicast group management device 10 for IP broadcasting of the present invention. Using FIG. 10, the operation flow in which the IP broadcasting multicast group management device 10 responds to the multicast address cancellation request from the IP broadcasting server 20 and cancels the multicast address will be described. This operation flow is executed by CPU 15 of the IP broadcasting multicast group management device 10.

First, the IP broadcasting multicast group management device 10 determines whether or not a multicast address / cancellation request message (MCA Return) including an IP broadcasting channel identifier has been received from the IP broadcasting server 20 via the network (step 201). .. When a multicast address / cancellation request message is received, the IP broadcast channel identifier and multicast address are extracted from the multicast address / cancellation request message, and the received IP broadcast is referred to by referring to the IP broadcast channel identifier-multicast address / binding table 11. Determine if the channel identifier and multicast address exist (steps 402,403).

Next, in step 403, if the IP broadcast channel identifier and the multicast address exist, the received IP broadcast channel identifier and the multicast address are deleted from the IP broadcast channel identifier-multicast address binding table 11, and the multicast address is changed. Generate a resolution response message (MCA Return ACK) and send it to the IP broadcast server (step 404). Also, in the multicast address pool table 12, change the allocation status to "assignable". Furthermore, in the IP broadcast channel management table management table 13, the status of the status is changed to "not broadcast". As a result, the IP broadcasting server 20 returns the right to use the multicast address to the multicast group management device 10 for IP broadcasting. As a result, the multicast address can be reused, and the multicast network 40 can be operated efficiently.

FIG. 11 is a diagram illustrating the above-mentioned multicast address allocation cancellation sequence. The IP broadcasting server 20 ends the IP broadcasting at time t2 (step 150). Next, the IP broadcasting server 20 transmits a multicast address / cancellation request message (MCA Return) to the IP broadcasting multicast group management device 10 (step 151). As shown in FIG. 10, the multicast group management device 10 for IP broadcasting cancels the allocation of the multicast address by referring to the multicast binding table 11 (step 152), and cancels the multicast address / cancellation response message (MCA Return). ACK) is transmitted to the IP broadcasting server 30 (step 153). As a result, the IP broadcasting server 20 returns the right to use the multicast address, and the multicast group management device 10 for IP broadcasting can reuse the multicast address.

FIG. 12 shows another embodiment of the multicast address pool table 12 in the multicast group management device 10 for IP broadcasting in the system of this embodiment. The multicast group management device 10 for IP broadcasting stores information for assigning a multicast address in the multicast network 40 in advance.

As is clear from FIG. 12, in this embodiment, unlike the table of the embodiment shown in FIG. 8, in addition to the multicast address 13a and the allocation status 13b, the information item of the transfer priority 13c of the IP packet is included. As a result, the IP broadcasting multicast group management device 10 can assign a multicast address that satisfies the conditions when, for example, a request for a high-priority multicast address is received from the IP broadcasting server.

FIG. 13 shows another embodiment of the multicast address pool table in this embodiment. In this embodiment, in addition to the multicast address 13a and the allocation status 13b, the information item of the network area information 13d capable of transmitting the IP packet at the multicast address 13a is included. As a result, the multicast group management device 10 for IP broadcasting satisfies the condition when, for example, receives a request from the IP broadcasting server 20 for the multicast address 13a for executing IP broadcasting in a limited area (region). Address 13a can be assigned.

Subsequently, FIG. 14 shows a flowchart of the channel switching operation executed by the IP broadcasting terminal in this embodiment. Currently, the IP broadcasting terminal 30 is receiving the IP broadcasting indicating the multicast address A. First, the IP broadcasting terminal 30 determines whether or not it has received the IP broadcasting channel identifier including the IP broadcasting channel information newly viewed by the user (step 501). Next, when the IP broadcast channel identifier is received, a multicast address query message including this IP broadcast channel identifier is transmitted (step 502).

Next, it is determined whether or not a multicast address response message including the transmitted IP broadcast channel identifier and the corresponding multicast address B has been received (step 503). Next, when the multicast address response message is received, the participation message to the multicast group B is sent to the multicast network (step 504). At the same time, an exit message to the multicast group A is sent to the multicast network (step 505). As a result, the IP broadcasting channel can be switched from the IP broadcasting channel indicating the multicast group A to the IP broadcasting channel indicating the multicast group B. Although steps 504 and 505 are in no particular order, the channel switching time can be shortened for the user by preceding step 504.

FIG. 15 shows a message sequence diagram of channel switching executed by the IP broadcasting terminal in this embodiment.

At time t1, the IP broadcast terminal is receiving the IP broadcast channel indicating the multicast address A (step 160). In order for the user to view the IP broadcast channel B at time t2, the IP broadcast channel B request signal including the IP broadcast channel identifier is input or transmitted to the IP broadcast terminal 30 (step 161). The IP broadcasting terminal 30 transmits a multicast address / query message including the IP broadcasting channel identifier to the IP broadcasting multicast group management device 10 (step 162). Next, the IP broadcasting multicast group management device 10 transmits a multicast address response message including the determined multicast address B to the IP broadcasting terminal 30 (step 163).

Next, the IP broadcasting terminal 30 is arranged in the multicast network and transmits a participation message to the multicast group B or a video reception request message to a multicast router (not shown) (step 164). At the same time, the IP broadcasting terminal 30 transmits a participation message to the multicast group A or a video distribution cancellation message (step 165). As a result, the IP broadcasting terminal 30 switches from the video of the IP broadcasting channel indicating the multicast group A to the video of the IP broadcasting channel indicating the multicast group B. As described above, by preceding the video reception request (IGMP Join B) 164 with the video reception cancellation (IGMP Leave A) 165, the channel switching time can be shortened for the user.

The specific configuration of the set-top box 80 for realizing the IP broadcasting system of the present embodiment shown in FIG. 1 and its operation will be described with reference to FIGS. 16 to 20. 16 and 17 are diagrams showing an embodiment of the configuration of the set-top box 80, FIG. 16 is a functional configuration diagram thereof, and FIG. 17 is a circuit configuration diagram thereof.

First, in FIG. 16, the set-top box 80 is composed of a video data control unit 81, a transfer unit 82, and a memory 83 for storing user information such as IP broadcast channel information. The video data control unit 81 generates a video distribution request message to the multicast network 40. When a video reception request message is received from the IP broadcasting terminal 30, a transfer command is sent to the transfer unit 82. The memory 83 stores the IP broadcasting channel information that can be viewed by the user using the IP broadcasting terminal 30. In the figure, other functional parts as a set-top box, that is, the media conversion function part described above and the like are not shown.

The video data control unit 81 transmits a video distribution request message in advance based on the IP broadcast channel information stored in the memory 83. As a result, the set-top box 80 is in a state of continuously receiving a plurality of video data. In this state, when the set-top box 80 receives a video reception request message from the IP broadcasting terminal 30, the video data control unit 81 analyzes the received video reception request message and sends a transfer command to the transfer unit 82. Start transferring video data. As a result, the IP broadcasting terminal 30 can receive the video data.

FIG. 17 shows a specific configuration of the set-top box 80 corresponding to FIG. 84, 85, and 86 are a processing unit (CPU) that executes programs such as transfer control processing, a memory that stores programs, and a cache memory that stores information and data, respectively. The cache memory 86 temporarily stores the same information as the IP broadcast channel identifier-multicast address biting table 11 described above. 87 and 89 are the external interface unit (IF) which is the transmission / reception unit of the set top box 80, and 88 is the packet transfer processing unit, which executes the packet transfer processing under the control of the CPU 84 which is the video data control unit 81. Corresponds to the transfer unit 82 in FIG.

Next, an example of a specific operation of the set-top box 80 will be described with reference to FIGS. 18, 19, and 20. In FIG. 18, first, the set-top box 80 is in the initial state and does not receive any video (180). Therefore, the set-top box 80 inquires of the currently available broadcast to the IP broadcasting multicast group management device 10 which is an IP broadcasting channel management server (181). The set-top box 80 then sends a user-viewable video delivery request message (182). As a result, the set-top box 80 can receive a plurality of videos corresponding to the transmitted video distribution request message (183).

FIG. 19 is a diagram illustrating a case where the video is delivered (190) to the set-top box 80 in advance. In this case, the set-top box 80 receives the multicast address query message, which is a query message including the IP broadcast channel identifier described above, from the IP broadcast terminal 30 (191). The CPU 84 searches the cache memory 86 to see if a multicast address corresponding to the IP broadcast channel identifier exists (192). If it exists, it records the multicast address in a response message and sends it to the IP broadcasting terminal 30 (194). If it does not exist, the CPU 84 controls the multicast address inquiry message to be forwarded to the IP broadcasting multicast group management device 10 for inquiry (193). As a result, the set-top box 80 receives a multicast address response message (195) and updates the contents of cache memory 86 based on it (196).

FIG. 20 shows an example of video distribution when an authentication function for a video reception request message is added as a processing function of the set-top box 80, that is, the CPU 84. First, the set-top box 80 receives a video reception request message from the IP broadcasting terminal 30 (197). At this time, the set-top box 80 first authenticates this request message, and based on the authentication result, transfers only the corresponding video packet to the IP broadcasting terminal 30.

As described in detail above, according to the present invention, in a multicast network capable of multicast routing, the load of setting the multicast address of the user can be reduced, and the load of setting the multicast to the IP broadcasting terminal can be reduced. It is possible to provide a system and a multicast group management device for IP broadcasting suitable for the system.

<figref num="1">The figure for demonstrating the IP broadcasting communication system, the multicast address management apparatus for IP broadcasting, and the IP broadcasting terminal to which the IP broadcasting channel management system of 1st Example of this invention is applied.</figref><figref num="2">FIG. 5 is a flowchart of a multicast address resolution operation executed by the IP broadcasting terminal of the first embodiment.</figref><figref num="3">FIG. 5 is a flowchart of a multicast address resolution operation executed by the IP broadcasting multicast address management device of the first embodiment.</figref><figref num="4">The figure which shows the configuration example of the IP broadcast channel identifier-multicast address binding table of 1st Example.</figref><figref num="5">The figure which shows the configuration example of the IP broadcasting channel management table of 1st Example.</figref><figref num="6">The figure which shows the message format example of 1st Example.</figref><figref num="7">FIG. 5 is a flowchart of a multicast address allocation operation executed by the IP broadcasting multicast address management device of the first embodiment.</figref><figref num="8">The figure which shows the configuration example of the multicast address pool table of 1st Example.</figref><figref num="9">The basic message sequence diagram in the IP broadcasting communication system of the first embodiment.</figref><figref num="10">The figure which shows the elimination operation flowchart of the multicast address executed by the multicast address management apparatus for IP broadcasting of 1st Example.</figref><figref num="11">The message sequence diagram of the multicast address resolution of the first embodiment.</figref><figref num="12">The figure which shows the configuration example of the multicast address pool table of 1st Example.</figref><figref num="13">The figure which shows the configuration example of the multicast address pool table of 1st Example.</figref><figref num="14">The flowchart of the channel switching operation executed by the IP broadcasting terminal of 1st Example.</figref><figref num="15">The message sequence diagram of the channel switching executed by the IP broadcasting terminal of the first embodiment.</figref><figref num="16">The functional diagram for demonstrating the set-top box for realizing the IP broadcasting communication system of 1st Example.</figref><figref num="17">The block diagram for demonstrating the set-top box for realizing the IP broadcasting communication system of 1st Example.</figref><figref num="18">The flow diagram for demonstrating the function of the set-top box of 1st Example.</figref><figref num="19">The flow diagram for demonstrating the function of the set-top box of 1st Example.</figref><figref num="20">First Example A flow diagram for explaining the function of a set-top box.</figref>

Code description

10 ... IP Broadcast Multicast Address Management Device, 20 ... IP Broadcast Server, 30 ... IP Broadcast Terminal, 50 ... IP Broadcast Portal Server, 11 ... IP Broadcast Channel Identifier-Multicast Address Buy Ding table, 12 ... Multicast address pool table, 13 ... IP broadcast channel management table, 14 ... I / O interface, 15 ... CPU, 31 ... GE interface, 32 ... Packet Processing unit, 33 ... MPEG processing unit, 34 ... cache memory, 35 ... CPU, 80 ... set top box, 81 ... video data control unit, 82 ... transfer unit, 83. .. IP broadcast channel information, 84 ... CPU, 85 ... memory, 86 ... cache memory, 87, 89 ... interface, 88 ... packet transfer processing unit.