Mutlicast hierarchy system, distribution server, address allocating server and hierarchizing method

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a multicast layering system, a distribution server, an address allocation server, and a multicast layering method for distributing layer-encoded stream data, and knows the multicast layer according to the optimum performance in a receiving terminal, and multicasts without waste. The present invention relates to a multicast layering system for communication, a distribution server, an address allocation server, and a multicast layering method.

【0002】

[Conventional technology]

In recent years, various communication networks have been used with the advanced information society. In particular, the Internet is rapidly expanding and developing all over the world because it does not require an expensive switchboard and a network can be constructed by an inexpensive router. In addition, with the expansion and development, there has been a problem of exhaustion of IP addresses (Internet Protocol Address: addresses that identify the location of devices connected to the network) assigned to each user. However, the version has been upgraded from an IPv4 (Internet Protocol Version 4) network that uses 32-bit IP addresses that show address information for about 4.3 billion pieces to an IPv6 (Internet Protocol Version 6) network that uses 128-bit IP addresses. It will be solved by doing so, and further expansion and development is expected.

【0003】

Under these circumstances, various services using IPv4 or IPv6 protocols (Protocol: agreement for data communication including IP address), especially the Internet, are provided. There is. For example, it is a service that distributes moving images and the like corresponding to devices used by individuals using the Internet, that is, hierarchically coded stream data.

【0004】

[Problems to be Solved by the Invention]

However, in order to realize this service efficiently, it is necessary to optimally hierarchically code the stream data, and the server that provides the service needs to make the delivered service correspond to the performance of the device used by the individual. ..

【0005】

Therefore, layered encoding string layered multicast method for distributing Mudeta have been proposed. Generally, in layered multicast, some layered streams complement the layers below and are encoded so that the quality is so good that many layers are available. For example, when it is coded in three layers, it is better to combine the first layer and the second layer than the first layer alone, and to cover all the layers rather than the first layer and the second layer. The better the combination, the better the quality. The sender only needs to multicast the layered stream to as many groups as there are layers, and by selecting the group in which the recipient should participate, it is diverse without the need to send unnecessary data. It can handle a large number of recipients in various environments.

【0006】

Specific methods of layered multicast include, for example, Receiver-driven Layered Multicast (hereinafter referred to as RLM) (Steven McCanne, et al. "Receiver-driven Layered Multicast", in Proceedings of SIGCOM M'96, pp. 117-130, Aug. 1996). RLM uses the packet loss rate as an index when selecting a group in which the recipient participates. If the loss rate over a period of time exceeds a certain threshold, the recipient drops one hierarchy. In the above example, the first layer to the third layer were received, but since the loss rate is large, the reception of the third layer is canceled. On the contrary, if the loss rate in a certain period of time does not exceed a certain threshold, the receiving layer is increased by one. As described above, each receiver can receive the stream data with the quality corresponding to the available network bandwidth.

【0007】

Further, Japanese Patent Application Laid-Open No. 10-23380 reports a method similar to layered multicast. In Japanese Patent Application Laid-Open No. 10-23380, images that are hierarchically coded by the progressive method are not divided into multicast groups for the number of layers and transmitted, but all are transmitted to one multicast group. To do. Each receiver receives data in all layers, but decompresses using only the data in the layers that satisfy the preset quality. Based on the above, it is claimed that images can be delivered with the quality required by each receiver without increasing the communication traffic when compared with the case of unicasting with the quality required by each receiver.

【0008】

In addition, RLM states that the bottleneck of communication quality is network bandwidth. However, when entering the broadband era and when a wide variety of terminals are connected to the network, the bottleneck of communication quality is not only the bandwidth of the network but also the capacity of the terminals. Conceivable. However, the existing layered multicast method, represented by RLM, does not take into account the capabilities of terminals. Further, Japanese Patent Application Laid-Open No. 10-23380 has a problem in that the received image quality cannot be set automatically. Furthermore, since all recipients receive data of all layers, there is a problem in that communication traffic becomes large when compared with RLM.

【0009】

In addition, in order to correspond to the equipment performance used by individuals, as shown in JP-A-7-302236 and JP-A-11-341074, the operator of the equipment being used must check the equipment performance in advance. I had to register manually. I also needed an application for registration.

【0010】

An object of the present invention has been made in view of the above points, and by using IPv6 (a terminal identifier is implemented in the address part) of the next-generation Internet protocol, the device performance of the receiving terminal can be improved. It is an object of the present invention to provide a multicast layering system, a distribution server, an address allocation server, and a layering method capable of automatically knowing the optimum layer without manual registration and enabling lean multicast communication.

【0011】

[Means for solving problems]

In the present invention, in order to solve the above problems, in a multicast layered system that distributes layer-coded stream data, multicast participation information is transmitted, an IP multicast address is received, and based on the received IP multicast address. A receiving terminal that participates in a multicast group, a distribution server that transmits search information and receives an IP multicast address, a terminal capacity database server that searches for and transmits the corresponding capability information using the multicast participation information as a key, and a distribution server. Receives search information from, receives multicast participation information from the receiving terminal, sends multicast participation information to the terminal capability database server, then receives the retrieved capability information, searches the address database for multicast addresses, and multicast addresses. Provided is a multicast layered system characterized by having a distribution server and an address allocation server that transmits data to a receiving terminal.

【0012】

According to the above configuration, in so-called layered multicast, the optimum layer is known in the receiving terminal by providing an address allocation server and a terminal capability database server and by using a communication protocol capable of implementing a terminal identifier. It is possible to provide lean multicast communication.

【0013】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a principle diagram of the multicast layered system of the present invention.

【0014】

The multicast layered system 1 centrally manages the receiving terminal 10 that receives data such as moving images, the distribution server 20 that distributes data such as moving images by multicast, the address allocation server 30 that assigns multicast addresses, and the capability information of terminals. It is composed of a database server 40 and a network 50 that transmits information as an IP packet (Packet: a collection of encapsulated data when transmitting information in a network).

【0015】

The receiving terminal 10 is connected to the distribution server 20 and the address allocation server 30 via the network 50, and receives data such as moving images. It also receives a stream from the distribution server 20 and a stream list and a multicast address from the address allocation server 30. Further, the stream list request, the terminal identifier, and the stream identifier are sent to the address allocation server 30.

【0016】

The distribution server 20 is connected to the receiving terminal 10 and the address allocation server 30 via the network 50, and distributes data such as moving images by multicast. It also receives a multicast address from the address allocation server 30. Further, a stream is transmitted to the receiving terminal 10, and the number of multicast groups and stream identifiers that are address requests and an address return request are transmitted to the address allocation server 30.

【0017】

The address allocation server 30 is connected to the receiving terminal 10, the distribution server 20, and the terminal capability database server 40 via the network 50, and assigns a multicast address. Further, the receiving terminal 10 receives the list request, the terminal identifier, and the stream identifier, the distribution server 20 receives the address request and the address return request, and the terminal capacity database server 40 receives the capacity information. On the other hand, the stream list and address are transmitted to the receiving terminal 10, the multicast address is transmitted to the distribution server 20, and the terminal identifier is transmitted to the terminal capability database server 40.

【0018】

The terminal capability database server 40 is connected to the address allocation server 30 via the network 50, and centrally manages the correspondence between the terminal identifier and the capability information. It also receives the terminal identifier from the address allocation server 30. Further, the capability information is transmitted to the address allocation server 30.

【0019】

The network 50 transmits information based on a predetermined protocol in a network in which communication paths are stretched. The protocol is, for example, TCP / IP (Transmission Control Protocol / Internet Protocol), IPv6, HTTP (Hypertext Transfer Protocol), or FTP (File Transfer Protocol). The network 50 is, for example, a public network, an IPv6 Internet, or an Internet 2 (hereinafter, both referred to as IPv6 networks).

【0020】

According to such a multicast layered system, the address allocation server 30 receives the address request, the terminal identifier, the stream identifier, and the capability information transmitted from the receiving terminal 10, the distribution server 20, and the terminal capability database server 40. To do. Then, based on them, it is possible to inform the receiving terminal 10 of the optimum multicast address.

【0021】

As a result, the optimum layer can be known at the receiving terminal, and it becomes possible to provide lean multicast communication. Hereinafter, embodiments of the present invention will be specifically described.

【0022】

In the embodiment of the present invention, in the system as shown in FIG. 1, the receiving terminal 10, the distribution server 20, the address allocation server 30, and the terminal capability database server 40 are connected via the network 50. Among them, between the receiving terminal 10 and the distribution server 20, between the receiving terminal 10 and the address allocation server 30, between the distribution server 20 and the address allocation server 30, and between the address allocation server 30 and the terminal capability database server 40. Data is transmitted to and from each of them. Therefore, taking the case of transmitting data to the opposite device or receiving data from the opposite device as an example, the functions of each device in the present embodiment will be specifically described below.

【0023】

FIG. 2 is a functional block diagram showing the processing function of the receiving terminal of the present invention. The receiving terminal 10 is composed of a receiving unit 11 that receives multicast data, a processing unit 12 that is in charge of overall processing, and a network interface 13 that communicates via the network 50. Here, the receiving unit 11 is subdivided into receiving units 11a to 11m. Further, the receiving terminal 10 faces the distribution server 20 and the address allocation server 30 via the network 50, respectively.

【0024】

The receiving unit 11 is connected to the processing unit 12 and the network interface 13, receives multicast data of the corresponding hierarchy from the network interface 13, and outputs the multicast data to the processing unit 12. Here, the receiving unit 11 is, for example, a computer program, which is stored in a memory (Memory) (not shown) and executed by a CPU (Central Processing Unit) (not shown) to realize the function of the present invention.

【0025】

The processing unit 12 is connected to the receiving unit 11 and the network interface 13 to perform overall control and processing. Here, the processing unit 12 receives the request from the receiving unit 11 and outputs the communication data with the address allocation server 30 to the network interface 13. Further, the processing unit 12 is, for example, a computer program, which is stored in a memory (not shown) and executed by a CPU (not shown) to realize the function of the present invention.

【0026】

The network interface 13 is connected to the receiving unit 11 and the processing unit 12, and communicates between the distribution server 20 and the address allocation server 30 via the network 50. Here, the network interface 13 is a device and is connected to the network 50 via a communication medium. The communication medium is, for example, a physical medium such as a wired metal cable or an optical fiber, or a wireless medium.

【0027】

FIG. 3 is a functional block diagram showing the processing function of the distribution server of the present invention. The distribution server 20 includes a distribution unit 21 that distributes multicast data, a processing unit 22 that is in charge of overall processing, and a network interface 23 that communicates via the network 50. Here, the distribution unit 21 is subdivided into distribution units 21a to 21n. Further, the distribution server 20 faces the receiving terminal 10 and the address allocation server 30 via the network 50, respectively.

【0028】

The distribution unit 21 is connected to the processing unit 22 and the network interface 23, and distributes the multicast data layered for each unit from the network interface 23. Here, the distribution unit 21 is, for example, a computer program, which is stored in a memory (not shown) and executed by a CPU (not shown) to realize the function of the present invention.

【0029】

The processing unit 22 is connected to the distribution unit 21 and the network interface 23, and performs overall control and processing. Here, the processing unit 22 receives the request from the distribution unit 21 and outputs the communication data with the address allocation server 30 to the network interface 23. Further, the processing unit 22 is, for example, a computer program, which is stored in a memory (not shown) and executed by a CPU (not shown) to realize the function of the present invention.

【0030】

The network interface 23 is connected to the distribution unit 21 and the processing unit 22, and communicates between the receiving terminal 10 and the address allocation server 30 via the network 50. Here, the network interface 23 is a device and is connected to the network 50 via a communication medium. The communication medium is, for example, a physical medium such as a wired metal cable or an optical fiber, or a wireless medium.

【0031】

FIG. 4 is a functional block diagram showing the processing function of the address allocation server of the present invention. The address allocation server 30 includes a registration unit 31 that registers requests from the distribution server 20, a search unit 32 that searches for multicast addresses, a processing unit 33 that handles overall processing, an inquiry unit 34 that inquires about the capabilities of receiving terminals, and a network 50. It is composed of a network interface 35 that communicates via. Here, the address allocation server 30 faces the receiving terminal 10, the distribution server 20, and the terminal capability database server 40 via the network 50, respectively.

【0032】

The registration unit 31 is connected to the processing unit 33 and the address database 36. Further, based on the information sent from the processing unit 33, the identifier of the stream distributed by the distribution server 20 is registered in the address database 36. This allows the requested number of multicast addresses to be passed. Here, the registration unit 31 is, for example, a computer program, which is stored in a memory (not shown) and executed by a CPU (not shown) to realize the function of the present invention.

【0033】

The search unit 32 is connected to the processing unit 33 and the address database 36, and searches for the multicast address corresponding to the search request. Further, the search unit 32 is, for example, a computer program, which is stored in a memory (not shown) and executed by a CPU (not shown) to realize the function of the present invention.

【0034】

The processing unit 33 is connected to the registration unit 31, the search unit 32, the inquiry unit 34, and the network interface 35, and performs overall control and processing. Here, the processing unit 33 receives the request from the distribution server 20 from the network interface 35, and issues a request registration instruction to the registration unit 31. Further, the processing unit 33 receives a multicast address search request corresponding to the terminal capability from the receiving terminal 10 from the network interface 35, and issues a search instruction to the search unit 32. Further, the processing unit 33 inquires about the terminal capability of the receiving terminal 10. The processing unit 33 is, for example, a computer program, which is stored in a memory (not shown) and executed by a CPU (not shown) to realize the function of the present invention.

【0035】

The inquiry unit 34 is connected to the processing unit 33 and the address database 36, and inquires of the terminal capacity of the receiving terminal 10 to the terminal capacity database server 40. Here, the inquiry unit 34 is, for example, a computer program, which is stored in a memory (not shown) and executed by a CPU (not shown) to realize the function of the present invention.

【0036】

The address database 36 is connected to the registration unit 31 and the search unit 32, holds available multicast addresses, stream identifiers corresponding to already assigned multicast addresses, and receiving terminal capability information, and centrally manages them. Here, the address database 36 is a rewritable storage medium, such as a hard disk or a memory.

【0037】

The network interface 35 is connected to the processing unit 33 and the inquiry unit 34, and communicates between the receiving terminal 10 and the distribution server 20 via the network 50. Here, the network interface 35 is a device and is connected to the network 50 via a communication medium. The communication medium is, for example, a physical medium such as a wired metal cable or an optical fiber, or a wireless medium.

【0038】

Next, the processing flow of each device will be specifically described. FIG. 5 is a flowchart illustrating the basic operation of the receiving terminal of the present invention. The description of this flowchart is based on FIG. 1 which is a principle diagram for the name of each device, and FIG. 2 which is a functional block diagram for the name of each part of the device. Further, in the description, the required number of multicast groups is the number of layers of layered stream data. Here, this number of layers will be described as m. Furthermore, which layer the m multicast addresses correspond to is determined to be unique to the entire system, such as in ascending or descending order.

【0039】

[S100] The processing unit 12 sends a list request for the multicast stream to the address allocation server 30.

[S101] The processing unit 12 receives the list of streams transmitted from the address allocation server 30.

【0040】

[S102] The processing unit 12 waits for the stream to be received to be selected by inquiring to the user who is the operator of the receiving terminal 10 based on the list of received streams.

【0041】

[S103] The processing unit 12 transmits its own terminal identifier and the identifier of the stream to be received to the address allocation server 30.

[S104] The processing unit 12 receives m addresses transmitted from the address allocation server 30. Then, the multicast address is passed to each of the m receiving units 11a to 11m.

【0042】

[S105] The receiving unit 11 joins the multicast group based on the multicast address transmitted from the address allocation server 30.

[S106] The receiving unit 11 receives the stream transmitted by multicast from the distribution server 20.

【0043】

[S107] If the receiving unit 11 decides not to receive the multicast data any more, or if the distribution by the distribution server 20 is completed, the process proceeds to step S108, and if not, the processing returns to step S106.

【0044】

[S108] The receiving unit 11 decides not to receive the multicast data any more, or the distribution by the distribution server 20 is completed, so that the receiving unit 11 leaves the participating multicast group.

【0045】

FIG. 6 is a flowchart illustrating the basic operation of the distribution server of the present invention. The description of this flowchart is based on FIG. 1 which is a principle diagram for the name of each device, and FIG. 3 which is a functional block diagram for the name of each device part. Further, in the description, the required number of multicast groups is the number of layers of layered stream data. Here, this number of layers will be described as n. Furthermore, which layer the n multicast addresses correspond to is determined to be unique to the entire system, such as in ascending or descending order.

【0046】

[S200] The processing unit 22 sends an address request including the required number of multicast groups, the required capacity information, and the stream identifier to the address allocation server 30.

【0047】

[S201] The processing unit 22 receives n addresses transmitted from the address allocation server 30.

[S202] The processing unit 22 that has received n addresses passes a multicast address to each of n distribution units 21a to 21n. After that, the n distribution units 21a to 21n block until the start of distribution. Here, when the predetermined delivery start time is reached, the process proceeds to step S203, and when the delivery start time is not reached, the process returns to step S201.

【0048】

[S203] The processing unit 22 multicasts the stream to the receiving terminal 10 at the distribution start time.

[S204] If the multicast distribution is completed by step S203, the process proceeds to step S205, and if it is not completed, the process returns to step S203.

【0049】

[S205] The processing unit 22 transmits an address return request including the identifier of the stream for which the multicast distribution has been completed to the address allocation server 30.

【0050】

FIG. 7 is a flowchart illustrating the basic operation of the address allocation server of the present invention. The description of this flowchart is based on FIG. 1 which is a principle diagram for the name of each device, and FIG. 4 which is a functional block diagram for the name of each part of the device. Further, in the description, the number of multicast groups required is the number of layers of layered stream data. Here, this number of layers will be described as m and n. Furthermore, which layer the m and n multicast addresses correspond to is determined to be unique to the entire system, such as in ascending or descending order.

【0051】

[S300] The processing unit 33 receives an address request including the number of multicast groups from the distribution server 20, the required capacity information, and the stream identifier.

【0052】

[S301] If there is an address request, the process proceeds to step S302, and if there is no address request, the process proceeds to step S304.

[S302] The processing unit 33 that has received the address request issues a registration request to the registration unit 31. In addition, the registration unit 31 passes the stream identifier, the number of layers n, and the required capability information to the address database 36. The passed address database 36 selects n available multicast addresses from the multicast addresses held in the database, registers the stream identifier and capability information in the database in association with each other, and registers n addresses for the registration unit 31. Pass the address. Further, the registration unit 31 passes n addresses to the processing unit 33.

【0053】

[S303] The processing unit 33, which has been passed n addresses, transmits n addresses to the distribution server 20.

[S304] If the list request from the receiving terminal 10 is received, the process proceeds to step S305, and if not received, the process proceeds to step S307.

【0054】

[S305] The processing unit 33 that has received the list request passes the list request to the search unit 32. The search unit 32 queries the address database 36 for all the stream identifiers currently held. The address database 36 passes all the stream identifiers currently held to the search unit 32. The search unit 32 to which the stream identifiers are passed creates a stream list including those identifiers.

【0055】

[S306] The processing unit 33 to which the stream list is passed transmits the stream list to the receiving terminal 10.

[S307] If the terminal identifier and the stream identifier from the receiving terminal 10 are received, the process proceeds to step S308, and if not received, the process proceeds to step S312.

【0056】

[S308] The processing unit 33 that has received the terminal identifier and the stream identifier passes the terminal identifier to the inquiry unit 34. The inquiry unit 34 transmits the terminal identifier to the terminal capability database server 40.

【0057】

[S309] The inquiry unit 34 receives the inquiry result from the terminal capacity database server 40, and passes the capacity information to the processing unit 33.

[S310] The processing unit 33 to which the capacity information is passed passes the stream identifier and the capacity information to the search unit 32. The search unit 32 passes the stream identifier and the capability information to the address database 36. The address database 36 selects a hierarchy suitable for ability information from the hierarchies corresponding to stream identifiers, and passes m multicast addresses assigned to the hierarchies to the search unit 32. The search unit 32 passes m addresses to the processing unit 33.

【0058】

[S311] The processing unit 33 transmits m addresses to the receiving terminal 10.

[S312] If the processing unit 33 receives the address return request from the distribution server 20, the process proceeds to step S313, and if it is not received, the processing returns to step S300.

【0059】

[S313] The processing unit 33 that has received the address return request passes the stream identifier to the registration unit 31. The registration unit 31 deletes the multicast address assignment corresponding to the stream identifier from the address database 36.

【0060】

FIG. 8 is a flowchart illustrating the basic operation of the terminal capability database server of the present invention. The description of this flowchart is based on FIG. 1, which is a principle diagram, with the names of each device.

【0061】

[S400] The terminal capacity database server 40 receives the terminal identifier for capacity inquiry from the address allocation server 30.

[S401] The terminal capability database server 40 that has received the terminal identifier searches for the capability of the terminal identified by the terminal identifier.

【0062】

[S402] The capability information that is the result of the search by step S401 is transmitted to the address allocation server 30. Next, the basic processing flow between the devices facing each other will be specifically described.

【0063】

FIG. 9 is a network sequence diagram illustrating the operation between the distribution server and the address allocation server of the present invention. Address request from distribution server-Reception is processed according to the following flow. The description of this flowchart is based on FIG. 1 which is a principle diagram for the name of each device, and FIGS. 3 and 4 which are functional block diagrams for the names of each part of the device. Further, in the description, the required number of multicast groups is the number of layers of layered stream data. Here, this number of layers will be described as n. Furthermore, which layer the n multicast addresses correspond to is determined to be unique throughout the system, such as in ascending or descending order.

【0064】

[S1000] The processing unit 22 of the distribution server 20 sends an address request including the required number of multicast groups, the required capacity information, and the stream identifier to the processing unit 33 of the address allocation server 30 ((S1000). This corresponds to step S200 already described).

【0065】

[S1001] In the address allocation server 30, the processing unit 33 receives an address request including the number of multicast groups from the distribution server 20, the required capacity information, and the stream identifier. Then, a registration request is issued to the registration unit 31 (this corresponds to step S300 and step S301 already described).

【0066】

[S1002] In the address allocation server 30, the registration unit 31 passes the stream identifier, the number of layers n, and the required capacity information to the address database 36 (this corresponds to step S302 already described).

【0067】

[S1003] In the address allocation server 30, the address database 36 selects n available multicast addresses from the multicast addresses held in the database, registers the stream identifier and the capability information in the database in association with each other, and registers the registration unit 31. Pass n addresses to (this corresponds to step S302 already described).

【0068】

[S1004] In the address allocation server 30, the registration unit 31 passes n addresses to the processing unit 33 (this corresponds to step S302 already described).

【0069】

[S1005] In the address allocation server 30, the processing unit 33, which has been passed n addresses, transmits n addresses to the distribution server 20 (this corresponds to step S303 already described).

【0070】

[S1006] In the distribution server 20, the processing unit 22 receives n addresses transmitted from the address allocation server 30. The processing unit 22 that has received the n addresses passes the multicast address to each of the n distribution units 21a to 21n. After that, n distribution units 21a to 21n block until the start of distribution (this corresponds to steps S201 and S202 already described).

【0071】

FIG. 10 is a network sequence diagram illustrating the operation between the receiving terminal, the address allocation server, and the terminal capability database of the present invention. Multicast address request from receiving terminal-Reception is processed according to the following flow. The description of this flowchart is based on FIG. 1 which is a principle diagram for the name of each device, and FIGS. 2 and 4 which are functional block diagrams for the names of each part of the device. Further, in the description, the required number of multicast groups is the number of layers of layered stream data. Here, this number of layers will be described as m and n. Furthermore, which layer the m and n multicast addresses correspond to is determined to be unique to the entire system, such as in ascending or descending order.

【0072】

[S2000] In the receiving terminal 10, the processing unit 12 transmits a list request for the multicast stream to the processing unit 33 of the address allocation server 30 (this corresponds to step S100 already described).

【0073】

[S2001] In the address allocation server 30, the processing unit 33 that has received the list request passes the list request to the search unit 32 (this corresponds to steps S304 and S305 already described).

【0074】

[S2002] In the address allocation server 30, the search unit 32 queries the address database 36 for all the stream identifiers currently held (this corresponds to step S305 already described).

【0075】

[S2003] The address database 36 passes all the stream identifiers currently held to the search unit 32 (this corresponds to step S305 already described).

【0076】

[S2004] In the address allocation server 30, the search unit 32 passed the stream identifiers creates a stream list including those identifiers (this corresponds to step S305 already described). The search unit 32 that created the stream list passes the stream list to the processing unit 33 (this corresponds to step S306 already described).

【0077】

[S2005] In the address allocation server 30, the processing unit 33 to which the stream list is passed transmits the stream list to the processing unit 12 of the receiving terminal 10 (this corresponds to step S306 already described).

【0078】

[S2006] In the receiving terminal 10, the processing unit 12 receives the stream list transmitted from the address allocation server 30. Then, based on the list of received streams, the user who is the operator of the receiving terminal 10 is inquired and waits for the stream to be received to be selected (this corresponds to steps S101 and S102 already described). To do).

【0079】

[S2007] In the receiving terminal 10, the processing unit 12 transmits its own terminal identifier and the identifier of the stream to be received to the address allocation server 30 (this corresponds to step S103 already described).

【0080】

[S2008] In the address allocation server 30, the processing unit 33 that has received the terminal identifier and the stream identifier passes the terminal identifier to the inquiry unit 34 (this corresponds to step S308 already described).

【0081】

[S2009] In the address allocation server 30, the query unit 34 transmits a terminal identifier to the terminal capability database server 40 (which corresponds to step S308 already described).

【0082】

[S2010] The terminal capability database server 40 that has received the terminal identifier searches for the capability of the terminal identified by the terminal identifier. After that, the result is transmitted to the inquiry unit 34 of the address allocation server 30 (this corresponds to step S400, step S401, and step S402 already described).

【0083】

[S2011] In the address allocation server 30, the inquiry unit 34 receives the inquiry result from the terminal capacity database server 40 and passes the capacity information to the processing unit 33 (this corresponds to step S309 already described). ..

【0084】

[S2012] In the address allocation server 30, the processing unit 33 to which the capacity information is passed passes the stream identifier and the capacity information to the search unit 32 (this corresponds to step S310 already described).

【0085】

[S2013] In the address allocation server 30, the search unit 32 passes the stream identifier and the capability information to the address database 36 (this corresponds to step S310 already described).

【0086】

[S2014] In the address allocation server 30, the address database 36 selects a hierarchy suitable for capacity information from the hierarchies corresponding to stream identifiers, and sends m multicast addresses assigned to the hierarchies to the search unit 32. (This corresponds to step S310 already described).

【0087】

[S2015] In the address allocation server 30, the search unit 32 passes m addresses to the processing unit 33 (this corresponds to step S310 already described).

【0088】

[S2016] In the address allocation server 30, the processing unit 33 transmits m addresses to the processing unit 12 of the receiving terminal 10 (this corresponds to step S311 already described).

【0089】

[S2017] In the receiving terminal 10, the processing unit 12 receives m addresses transmitted from the address allocation server 30. Then, the multicast address is passed to each of the m receiving units 11a to 11m (this corresponds to step S104 already described).

【0090】

FIG. 11 is a network sequence diagram illustrating the operation between the distribution server and the receiving terminal of the present invention. Stream distribution from the distribution server-Reception is processed according to the following flow. The description of this flowchart is based on FIG. 1 which is a principle diagram for the name of each device, and FIGS. 2 and 3 which are functional block diagrams for the names of each part of the device. Further, in the description, the required number of multicast groups is the number of layers of layered stream data. Here, this number of layers will be described as m and n. Furthermore, which layer the m and n multicast addresses correspond to is determined to be unique to the entire system, such as in ascending or descending order.

【0091】

[S3000] In the receiving terminal 10, each receiving unit 11a to 11m joins the multicast group based on the multicast address transmitted from the address allocation server 30 (this corresponds to step S105 already described). ..

【0092】

[S3001] In the distribution server 20, each distribution unit 21a to 21n multicasts a stream to the reception units 11a to 11m of the reception terminal 10 at the distribution start time (this is step S202, step already described). Corresponds to S203 and step S204). At the receiving terminal 10, the receiving unit 11 receives the stream multicast-transmitted from the server 20 (this corresponds to steps S106 and S107 already described).

【0093】

[S3002] In the receiving terminal 10, each receiving unit 11a to 11m leaves the participating multicast group when it is determined that the multicast data is not received any more or the distribution by the distribution server 20 is completed ((S3002). This corresponds to steps S107 and S108 already described).

【0094】

FIG. 12 is a network sequence diagram illustrating the operation between the distribution server and the address allocation server of the present invention. Address return request from distribution server-Delete is processed according to the following flow. The description of this flowchart is based on FIG. 1 which is a principle diagram for the name of each device, and FIGS. 3 and 4 which are functional block diagrams for the names of each part of the device.

【0095】

[S4000] In the distribution server 20, the processing unit 22 sends an address return request including the identifier of the stream for which the multicast distribution has been completed to the address allocation server 30 (this corresponds to step S205 already described). ).

【0096】

[S4001] In the address allocation server 30, the processing unit 33 that receives the address return request from the distribution server 20 passes the stream identifier to the registration unit 31 (this corresponds to steps S312 and S313 already described). To do).

【0097】

[S4002] In the address allocation server 30, the registration unit 31 deletes the multicast address assignment corresponding to the stream identifier from the address database 36 (this corresponds to step S313 described above).

【0098】

Next, the overall configuration, operation, and flow of one embodiment will be described with reference to specific examples. FIG. 13 is an overall configuration diagram showing a specific example of the multicast layered system of the present invention. The numbers shown in FIG. 13 (numbers circled) correspond to the following (1) to (7).

【0099】

Multicast layered systems can be applied to hierarchically coded streams and where multicast communication is available. Therefore, for example, an example of multicast distribution of video compressed by JPEG-2000 (Joint Photographic Experts Group-2000), which has a built-in progressive function as standard, using IPv6, which is the next-generation Internet protocol, will be described.

【0100】

First, the overall configuration will be described. The multicast layered system 1 includes a personal computer 10a (hereinafter referred to as receiver A), a mobile information terminal 10b (hereinafter referred to as receiver B), and a mobile phone 10c, which are classified into receiving terminals 10 that desire to receive video. (Hereinafter referred to as receiver C), the distribution server 20, the address allocation server 30, and the terminal capability database server 40 are configured in a network environment connected by a network 50 based on IPv6. Here, the mobile information terminal 10b and the mobile phone 10c are wirelessly connected to the network 50 via the base station 60.

【0101】

Next, the operation and flow (1) to (7) will be described. (1) The distribution server 20 divides the video into four layers according to the resolution progressive. Each layer is 80 x 60 (1st layer), 160 x 120 (2nd layer), 320 x 240 (3rd layer), and 640 x 480 (4th layer) in order from the lowest quality layer. .. At this time, the distribution server 20 gives the address allocation server 30 the number of layers (4), the ability (resolution) required for each layer, and the identifier of the stream to be distributed (arbitrary character string). Send.

【0102】

(2) The address allocation server 30 that received this information has four IPv6 multicast addresses, for example, ff18 :: 1234: 5678: 9abc: 0001 (first layer), ff18 :: 1234: 5678: 9abc: 0002 ( 2nd layer), ff18 :: 1234: 5678: 9abc: 0003 (3rd layer), and ff18 :: 1234: 5678: 9abc: 0004 (4th layer). Then, it is stored in the address database in association with the capability information, and these four addresses are transmitted to the distribution server 20.

【0103】

(3) The three receiving terminals 10 (in this example, the mobile phone 10c as a representative) transmit their own IPv6 address to the address allocation server 30 together with the identifier of the stream distributed by the distribution server 20.

【0104】

(4) The address allocation server 30 first transmits the IPv6 address of each terminal to the terminal capacity database 40 in order to acquire the capacity of each terminal from these IPv6 addresses.

【0105】

(5) Terminal capability database The server 40 searches the database it holds for capability information corresponding to the identifier of recipient A in these IPv6 addresses. As a result of the search, it is assumed that the resolution capacity of the receiver A is 1024 × 768, the resolution capacity of the receiver B is 160 × 120, and the resolution capacity of the receiver A is 80 × 60. Then, the terminal capacity database server 40 transmits the capacity information resulting from these to the address allocation server 30.

【0106】

(6) The address allocation server 30 that has acquired the terminal capability information searches the built-in address database 36 for the multicast address using the stream identifier and the capability information as keys. Then, the resulting one or more multicast addresses are transmitted to each receiving terminal 10 (in this example, the mobile phone 10c as a representative). For example, for recipient A, the resolution capability of 1024 x 768 can tolerate all layers of the stream being delivered, so ff18 :: 1234: 5678: 9abc: 0001 (first layer), ff18 :: 1234: All addresses of 5678: 9abc: 0002 (2nd layer), ff18 :: 1234: 5678: 9abc: 0003 (3rd layer), and ff18 :: 1234: 5678: 9abc: 0004 (4th layer) are sent. To.

【0107】

(7) The distribution server 20 multicasts the data of the corresponding layer (resolution component) to the group represented by the four multicast addresses. On the other hand, each receiving terminal 10 (in this example, the mobile phone 10c as a representative) participates in the multicast group notified from the address allocation server 30, and receives the video from the distribution server 20.

【0108】

With the above configuration, each receiving terminal 10 joins the multicast group notified from the address allocation server 30, and receives video with the optimum quality for the capabilities of each receiving terminal 10 without receiving unnecessary data. It becomes possible to do.

【0109】

In this embodiment, only the resolution is taken up as the capability information of the receiving terminal, but the present invention does not specify it, and it is possible to realize a multicast layered system according to various capability information.

【0110】

[Effect of the invention]

As explained above, since the optimum multicast hierarchy is known between the distribution server and the receiving terminal, the distribution server can transmit only the multicast data corresponding to the capability of the receiving terminal, which is unnecessary for the receiving terminal. It is possible to receive video with the optimum quality for the capabilities of each receiving terminal without receiving data.

[Simple explanation of drawings]

[Figure 1]

It is a principle diagram of the multicast layering system of this invention.

[Figure 2]

It is a functional block diagram which showed the processing function of the receiving terminal of this invention.

[Fig. 3]

It is a functional block diagram which showed the processing function of the distribution server of this invention.

[Fig. 4]

It is a functional block diagram which showed the processing function of the address allocation server of this invention.

[Fig. 5]

It is a flowchart explaining the basic operation of the receiving terminal of this invention.

[Fig. 6]

It is a flowchart explaining the basic operation of the distribution server of this invention.

[Fig. 7]

It is a flowchart explaining the basic operation of the address allocation server of this invention.

[Fig. 8]

It is a flowchart explaining the basic operation of the terminal capacity database server of this invention.

[Fig. 9]

It is a network sequence diagram explaining the operation between the distribution server and the address allocation server of this invention.

[Fig. 10]

It is a network sequence diagram explaining operation between a receiving terminal of this invention, an address allocation server, and a terminal capacity database.

[Fig. 11]

It is a network sequence diagram explaining the operation between the distribution server and the receiving terminal of this invention.

[Fig. 12]

It is a network sequence diagram explaining the operation between the distribution server and the address allocation server of this invention.

[Fig. 13]

It is an overall block diagram which shows the specific example of the multicast layering system of this invention.

[Explanation of symbols]

1 ... Multicast layered system, 10 ... Receiving terminal, 11, 11a ~ 11m ... Receiver, 12 ... Processing unit, 13 ... Network interface, 20 ... Distribution server, 21, 21a ~ 21n Distribution department, 22 Processing department, 23 Network interface, 30 Address allocation server, 31 Registration department, 32 Search department, 33 Processing Department, 34 ... Inquiry Department, 35 ... Network Interface, 36 ... Address Database, 40 ... Terminal Capacity Database Server, 50 ... Network