JP2003124991A - Multicast hierarchy system, distribution server, address assignment server, and hierarchy method - Google Patents

Abstract

(57) [Summary] [Problem] To deliver only multicast data corresponding to a device to be used. SOLUTION: A receiving terminal 10 receives data such as a moving image. The distribution server 20 performs multicast distribution of data such as moving images. Address assignment server 30
Assigns a multicast address. The terminal capability database server 40 centrally manages terminal capability information. The network 50 transmits information as IP packets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicast hierarchy system, a distribution server, an address allocation server and a multicast hierarchy method for distributing hierarchically encoded stream data, and particularly to a multicast hierarchy according to optimum performance at a receiving terminal. The present invention relates to a multicast hierarchy system, a distribution server, an address allocation server, and a multicast hierarchy method for performing efficient multicast communication.

[0002]

2. Description of the Related Art In recent years, various communication networks have been used along 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 exchange and can be constructed by an inexpensive router. With the expansion and development,
IP address assigned to each user (Internet Protoco
lAddress: There was a problem of exhaustion of the address that identifies the location of the device connected to the network. However, it shows about 4.3 billion pieces of address information up to then 3
IPv4 (Internet
Protocol Version4 (IPv4) using a 128-bit IP address from an IPv6 (Internet Protocol)
l Version6) The problem is solved by upgrading to a network, and further expansion and development are expected.

Under such circumstances, various services using the IPv4 or IPv6 protocol (Protocol: an agreement for data communication including an IP address), especially various services using the Internet, are available. It is provided. For example, it is a service that uses the Internet to distribute moving images and the like corresponding to devices used by individuals, that is, stream data that is hierarchically encoded.

[0004]

However, in order to efficiently realize this service, a method of optimally encoding stream data and a server providing the service are provided by an individual who uses the service to be distributed. It is necessary to correspond to the equipment performance that is present.

For this reason, many hierarchical multicast methods for delivering hierarchically encoded stream data have been proposed. Generally, in layered multicast, some layered streams are coded such that they complement the layers below and the quality is better as more layers are available. For example, when encoded in three layers,
It is better to combine the first and second layers than the first layer alone, and to combine all layers than the first and second layers.
The quality of each is improved. The sender only needs to multicast the layered streams to as many groups as there are layers, and by selecting the group to which the receiver should join, it is possible to use various streams without unnecessary data transmission. It can handle a large number of recipients in different environments.

A specific method of layered multicast is, for example, Receiver-driven Layered Multicast (hereinafter referred to as RLM) (Steven McCanne, et al.
"Receiver-driven Layered Multicast", in Proceeding
s of SIGCOMM'96, pp.117-130, Aug.1996). The RLM uses the packet loss rate as an index when selecting a group in which a receiver participates. If the loss rate over a certain time exceeds a certain threshold, the receiver drops one layer. 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 cancelled. On the contrary, if the loss rate in a certain time does not exceed a certain threshold, the layer to be received is increased by one. As described above, each receiver can receive the stream data with the quality according to the available network band.

Further, Japanese Patent Laid-Open No. 10-23380 reports a method similar to the layered multicast. In Japanese Laid-Open Patent Publication No. 10-23380, an image hierarchically encoded by the progressive method is not divided into multicast groups of the number of layers and transmitted, but all are transmitted to one multicast group. To do. Each receiver receives the data of all layers, but decompresses using only the data of the layers that satisfy the preset quality. As described above, it is claimed that the image can be delivered with the quality that meets the request without increasing the communication traffic, as compared with the case where the unicast is performed with the quality requested by each receiver.

Further, the RLM states that the bottleneck of communication quality is the network bandwidth. However, when entering the era of broadband, and when various types of terminals are connected to the network,
It is fully conceivable that the bottleneck of communication quality is not only the bandwidth of the network but also the capability of the terminal. However, the existing hierarchical multicast method represented by the RLM does not consider the capability of the terminal. Further, in Japanese Patent Laid-Open No. 10-23380, there is a problem in that the quality of the received image cannot be automatically set. Further, since all the receivers receive the data of all layers, there is a problem in that the communication traffic becomes large when compared with the RLM.

Further, in order to cope with the performance of the equipment used by an individual, as shown in JP-A-7-302236 and JP-A-11-341074, the operator of the equipment in use must be in advance. It was necessary to manually register the device performance. An application for registration was also needed.

The object of the present invention has been made in view of the above points, and by using IPv6 (a terminal identifier is mounted in the address part) of the next generation Internet protocol, You can automatically know the optimum hierarchy without manually registering device performance,
An object of the present invention is to provide a multicast hierarchization system, a distribution server, an address allocation server, and a hierarchization method that enable efficient multicast communication.

[0011]

According to the present invention, in order to solve the above-mentioned problems, in a multicast layered system for delivering layer-encoded stream data, multicast participation information is transmitted, an IP multicast address is received, A receiving terminal that joins the multicast group based on the received IP multicast address, a distribution server that transmits the search information and receives the IP multicast address, and the corresponding capability information is searched using the multicast participation information as a key and transmitted. Receiving the search information from the terminal capability database server and the distribution server,
Receives the multicast participation information from the receiving terminal, sends the multicast participation information to the terminal capability database server, receives the retrieved capability information, searches the address database for the multicast address, and sends the multicast address to the distribution server and the receiving terminal. A multicast layered system is provided which comprises a transmitting address allocation server.

According to the above configuration, in so-called layered multicast, 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 optimal for a receiving terminal. It is possible to know the hierarchy and to provide efficient multicast communication.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a principle diagram of a multicast hierarchical system of the present invention.

The multicast hierarchical system 1 integrates a receiving terminal 10 that receives data such as moving images, a distribution server 20 that multicasts data such as moving images, an address allocation server 30 that allocates multicast addresses, and capability information of terminals. Centrally managed terminal capacity database server 40, information in IP packet (Pack
et: Network 5 that transmits as a collection of parceled data when transmitting information in the network)
It consists of zero.

The receiving terminal 10 is connected to the distribution server 20 and the address assignment server 30 via the network 50 and receives data such as moving images. Further, the stream is distributed from the distribution server 20 to the address allocation server 3
Receive stream list and multicast address from 0. Further, the stream list request, the terminal identifier, and the stream identifier are transmitted to the address allocation server 30.

The distribution server 20 is connected to the receiving terminal 10 and the address allocation server 30 via the network 50, and multicasts data such as moving images. Also, the multicast address is received from the address allocation server 30. Further, the stream is transmitted to the receiving terminal 10, and the number of multicast groups and the stream identifier which are address requests and the address return request are transmitted to the address allocation server 30.

The address assignment server 30 includes the receiving terminal 10, the distribution server 20, and the terminal capacity database server 4.
It is connected to 0 via the network 50 and assigns a multicast address. Also, the list request, the terminal identifier, and the stream identifier are received from the receiving terminal 10, the address request and the address return request are received from the distribution server 20, and the capability information is received from the terminal capability database server 40. On the other hand, the stream list and the 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.

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

The network 50 transmits information based on a predetermined protocol within a network having communication paths. The protocol is, for example, TCP / IP.
(Transmission Control Protocol / Internet Protoco
l), IPv6, HTTP (Hypertext Transfer Protoc)
ol) or FTP (File Transfer Protocol). The network 50 is, for example, a public line network or IP.
The v6 Internet or the Internet 2 (hereinafter, both are referred to as an IPv6 network).

According to such a multicast hierarchical system, in the address allocation server 30, the receiving terminal 10, the distribution server 20 and the terminal capacity database server 4 are provided.
The address request, the terminal identifier, the stream identifier, and the capability information transmitted from 0 and 0 are received. Then, based on them, the receiving terminal 10 can be notified of the optimum multicast address.

As a result, the receiving terminal can know the optimum hierarchy, and it is possible to provide efficient multicast communication. Embodiments of the present invention will be specifically described below.

In the embodiment of the present invention, in the system as shown in FIG. 1, the receiving terminal 10 and the distribution server 2 are provided.
0, the address allocation server 30, and the terminal capability database server 40 are connected via the network 50. Among these, 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 capacity database server 40. Data transmission is performed between and. Therefore, taking the case of transmitting data to the opposite device or receiving data from the opposite device as an example,
The function of each device in the present embodiment will be specifically described below.

FIG. 2 is a functional block diagram showing the processing functions of the receiving terminal of the present invention. The receiving terminal 10 includes 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 is the distribution server 20.
And address allocation server 30 via network 50, respectively.

The receiving unit 11 is connected to the processing unit 12 and the network interface 13, receives the multicast data of the corresponding layer from the network interface 13, and outputs it to the processing unit 12. Here, the receiving unit 11
Is, for example, a computer program, stored in a memory (not shown), and a CPU (Cent) not shown.
The functions of the present invention are realized by being executed by a ral processing unit).

The processing unit 12 is connected to the receiving unit 11 and the network interface 13 and performs 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 1
Reference numeral 2 denotes a computer program, for example, which is stored in a memory (not shown) and executed by a CPU (not shown) to realize the function of the present invention.

The network interface 13 is connected to the receiving unit 11 and the processing unit 12, and via the network 50, the distribution server 20 and the address allocation server 30.
Communicate with. 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 optical fiber, or a wireless medium.

FIG. 3 is a functional block diagram showing the processing functions 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 responsible for overall processing, and a network interface 23 that communicates via the network 50. Here, the distribution unit 21 is the distribution units 21a to 21n.
Is subdivided into In addition, the distribution server 20 provides the receiving terminal 10 and the address allocation server 30 with the network 5
They are opposed to each other through 0.

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

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. The processing unit 22 is, for example, a computer program, is stored in a memory (not shown), and is executed by a CPU (not shown) to realize the functions of the present invention.

The network interface 23 is connected to the distribution unit 21 and the processing unit 22, and communicates with the receiving terminal 10 and the address allocation server 30 via the network 50. Here, the network interface 2
A device 3 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 optical fiber, or a wireless medium.

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

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

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

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. The processing unit 33 also 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, is stored in a memory (not shown), and is executed by a CPU (not shown) to implement the functions of the present invention.

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

The address database 36 is registered in the registration unit 31.
It is connected to the search unit 32 and holds the available multicast address, the stream identifier corresponding to the already assigned multicast address, and the receiving terminal capability information, and centrally manages them. Here, the address database 36 is a rewritable storage medium, and is, for example, a hard disk or a memory.

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, which 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 optical fiber, or a wireless medium.

Next, the processing flow of each device will be specifically described. FIG. 5 is a flowchart explaining the basic operation of the receiving terminal of the present invention. The description of this flowchart will be given based on FIG. 1, which is a principle diagram of the names of the respective devices, and FIG. 2, which is a functional block diagram of the names of the respective parts of the devices. Further, in the description, the number of required multicast groups is the number of hierarchical layers of stream data. Here, the number of layers will be described as m. Further, which hierarchy the m multicast addresses correspond to is determined in ascending order or descending order so as to be unique in the entire system.

[S100] The processing unit 12 transmits a list request for a stream to be multicast to the address allocation server 30. [S101] The processing unit 12 receives the list of streams transmitted from the address allocation server 30.

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

[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 reception units 11a to 11m.

[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 multicast-transmitted from the distribution server 20.

[S107] If the receiving unit 11 decides not to receive any more multicast data, or if the distribution by the distribution server 20 is completed, step S1.
If not completed, the process returns to step S106.

[S108] The receiving unit 11 decides not to receive any more multicast data, or leaves the multicast group in which it has participated because the distribution server 20 has finished distribution.

FIG. 6 is a flow chart for explaining the basic operation of the distribution server of the present invention. The description of this flowchart will be given based on FIG. 1, which is a principle diagram of names of respective devices, and FIG. 3, which is a functional block diagram of names of respective parts of the devices. Further, in the description, the number of required multicast groups is the number of hierarchical layers of stream data. Here, the number of layers will be described as n. Further, which hierarchy the n multicast addresses correspond to is determined in ascending order or descending order so as to be unique in the entire system.

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

[S201] The processing unit 22 receives the n addresses transmitted from the address allocation server 30. [S202] Processing unit 22 that has received n addresses
Passes the multicast address to each of the n distribution units 21a to 21n. After that, the n distribution units 21a to 21n block until the distribution starts. Here, if the predetermined distribution start time has been reached, the process proceeds to step S203, and if not, step S
The process returns to 201.

[S203] When the distribution start time comes, the processing unit 22 multicast-distributes the stream to the receiving terminal 10. [S204] If the multicast distribution is completed in step S203, the process proceeds to step S205, and if it is not completed, the process returns to step S203.

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

FIG. 7 is a flow chart for explaining the basic operation of the address allocation server of the present invention. The description of this flowchart will be given based on FIG. 1, which is a principle diagram showing names of respective devices, and FIG. 4, which is a functional block diagram showing names of respective parts of the devices. Further, in the description, the number of required multicast groups is the number of hierarchical layers of stream data. Here, the number of layers will be described as m and n. Further, which hierarchy the m and n multicast addresses correspond to is determined in ascending order or descending order so as to be unique in the entire system.

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

[S301] If there is an address request, the operation proceeds to step S302, and if there is no address request, the operation proceeds to step S304. [S302] The processing unit 33, which has received the address request,
A registration request is issued to the registration unit 31. In addition, the registration unit 31
Passes the stream identifier, the number of layers n, and required capability information to the address database 36. The delivered address database 36 selects n available from the multicast addresses stored in the database, registers the stream identifier and the capability information in association with each other in the database, and registers the n number of entries for the registration unit 31. Pass the address. Further, the registration unit 31 passes n addresses to the processing unit 33.

[S303] The processing unit 33, to which the n addresses are delivered, transmits the n addresses to the distribution server 20. [S304] If a list request from the receiving terminal 10 is received, the process proceeds to step S305, and if not, the process proceeds to step S307.

[S305] Upon receipt of the list request, the processing unit 33 passes the list request to the search unit 32. The search unit 32 inquires of the address database 36 about all stream identifiers currently held. The address database 36 passes all 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.

[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 are received from the receiving terminal 10, the process proceeds to step S308, and if not, the process proceeds to step S312.

[S308] The processing unit 33 which 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 capacity database server 40.

[S309] The inquiry unit 34 receives the inquiry result from the terminal capability database server 40, and passes the capability information to the processing unit 33. [S310] The processing unit 33, to which the capability information has been passed, passes the stream identifier and the capability 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 layer suitable for the capability information from the layers corresponding to the stream identifiers, and the search unit 32 searches for m multicast addresses assigned to the layer.
Pass to. The search unit 32 has a function of m
Pass each address.

[S311] The processing section 33 determines the receiving terminal 1
For 0, m addresses are transmitted. [S312] When the processing unit 33 receives the address return request from the distribution server 20, step S31.
If not received, the process returns to step S300.

[S313] Upon receiving the address return request, the processing unit 33 passes the stream identifier to the registration unit 31. The registration unit 31 deletes the allocation of the multicast address corresponding to the stream identifier from the address database 36.

FIG. 8 is a flow chart for explaining the basic operation of the terminal capacity database server of the present invention. The description of this flowchart will be given based on FIG. 1, which is the principle diagram of the name of each device.

[S400] The terminal capacity database server 40 receives the terminal identifier for the 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.

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

FIG. 9 is a network sequence diagram for explaining the operation between the distribution server and the address allocation server of the present invention. Address request-reception from the distribution server is processed according to the following flow. The description of this flowchart will be given based on FIG. 1, which is a principle diagram of names of respective devices, and FIGS. 3 and 4 which are functional block diagrams of names of respective parts of the devices. Also, in the explanation,
The number of required multicast groups is the number of hierarchical layers of stream data. Here, the number of layers will be described as n. Further, which hierarchy the n multicast addresses correspond to is determined in ascending order or descending order so as to be unique in the entire system.

[S1000] The processing unit 22 of the distribution server 20 issues an address request including the number of required multicast groups, required capability information, and stream identifier to the processing unit 33 of the address allocation server 30. Send (this is step S200 already described)
Corresponding to).

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

[S1002] In the address allocation server 30, the registration unit 31 makes the address database 3
The stream identifier, the number of layers n, and the required capability information are passed to step 6 (this is the step S30 already described).
2).

[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 association with each other in the database, Pass n addresses to the registration unit 31 (this corresponds to step S302 already described).

[S1004] In the address allocation server 30, the registration unit 31 passes n addresses to the processing unit 33 (this is the step S3 already described).
Corresponding to 02).

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

[S1006] In the distribution server 20, the processing unit 22 receives the n addresses transmitted from the address allocation server 30. The processing unit 22 that has received the n addresses delivers the multicast address to each of the n delivery units 21a to 21n. After that, the n delivery units 21a to 21n block until the delivery is started (this is because the step S201, which has already been described,
(Corresponding to step S202).

FIG. 10 is a network sequence diagram for explaining the operation between the receiving terminal, the address assigning server and the terminal capability database of the present invention. Multicast address request-reception from the receiving terminal is processed according to the following flow. The description of this flowchart will be given based on FIG. 1, which is a principle diagram of names of respective devices, and FIGS. 2 and 4 which are functional block diagrams of names of respective parts of the devices. Further, in the description, the number of required multicast groups is the number of hierarchical layers of stream data. Here, the number of layers will be described as m and n. Further, which hierarchy the m and n multicast addresses correspond to is determined in ascending order or descending order so as to be unique in the entire system.

[S2000] In the receiving terminal 10,
The processing unit 12 is the processing unit 3 of the address allocation server 30.
3, a list request for a stream to be multicast is sent (this is the step S10 already described).
Corresponding to 0).

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

[S2002] In the address allocation server 30, the search unit 32 causes the address database 3
6 is inquired of all stream identifiers currently held (this is done in step S30 already described).
5).

[S2003] Address database 3
6 passes all currently held stream identifiers to the search unit 32 (this corresponds to step S305 already described).

[S2004] In the address allocation server 30, the search unit 32 to which the stream identifier is passed
Creates a stream list containing 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).

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

[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 received stream list, the user who is the operator of the receiving terminal 10 is inquired to wait until the stream to be received is selected (this corresponds to step S101 and step S102 already described). To).

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

[S2008] In the address allocation server 30, the processing unit 33 which 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). .

[S2009] In the address allocation server 30, the inquiry unit 34 transmits the terminal identifier to the terminal capacity database server 40 (this corresponds to step S308 already described).

[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 is the step S40 already described).
0, corresponding to step S401 and step S402).

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

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

[S2013] In the address allocation server 30, the search unit 32 causes the address database 3
6, the stream identifier and the capability information are passed (this corresponds to step S310 already described).

[S2014] In the address allocation server 30, the address database 36 selects a layer suitable for the capability information from the layers corresponding to the stream identifier, and the m number of multicast addresses allocated to the layer is searched by the search unit. 32 to 32 (this corresponds to step S310 already described).

[S2015] In the address allocation server 30, the search unit 32 instructs the processing unit 33 to execute m
Number of addresses (this is the step S
Corresponding to 310).

[S2016] In the address allocation server 30, the processing unit 33 is the processing unit 1 of the receiving terminal 10.
2, m addresses are transmitted (corresponding to step S311 already described).

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

FIG. 11 is a network sequence diagram for explaining the operation between the distribution server and the receiving terminal of the present invention. Stream distribution-reception from the distribution server is processed according to the following flow. The description of this flowchart will be given based on FIG. 1, which is a principle diagram of names of respective devices, and FIGS. 2 and 3 which are functional block diagrams of names of respective parts of the devices. Further, in the description, the number of required multicast groups is the number of hierarchical layers of stream data. Here, the number of layers will be described as m and n. Further, which hierarchy the m and n multicast addresses correspond to is determined in ascending order or descending order so as to be unique in the entire system.

[S3000] In the receiving terminal 10,
Each of the reception units 11a to 11m includes the address allocation server 3
Join the multicast group based on the multicast address sent from 0 (this corresponds to step S105 already described).

[S3001] In the distribution server 20, each of the distribution units 21a to 21n multicasts the stream to the reception units 11a to 11m of the reception terminal 10 at the distribution start time (this is the step already described). S202, step S203, step S20
4). In the receiving terminal 10, the receiving unit 11
Receives the stream multicast-transmitted from the server 20 (this is the step S10 already described).
6, corresponding to step S107).

[S3002] At the receiving terminal 10,
Each of the receiving units 11a to 11m decides not to receive any more multicast data, or leaves the participating multicast group when the distribution server 20 finishes the distribution (this is the step S107 already described). , Corresponding to step S108).

FIG. 12 is a network sequence diagram for explaining the operation between the distribution server and the address allocation server of the present invention. Address return request-deletion from the distribution server is processed according to the following flow. In addition,
The description of this flowchart will be given based on FIG. 1 which is a principle diagram of names of respective devices and FIG. 3 and FIG. 4 which is a functional block diagram of names of respective parts of the devices.

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

[S4001] In the address allocation server 30, the processing unit 33 which receives the address return request from the distribution server 20 passes the stream identifier to the registration unit 31 (this is the step S3 already described).
12, corresponding to step S313).

[S4002] In the address allocation server 30, the registration unit 31 has the address database 3
From 6, delete the assignment of the multicast address corresponding to the stream identifier (this corresponds to step S313 already described).

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

The multicast hierarchical system can be applied when a hierarchically codeable stream and multicast communication are available. So, for example, JPEG-2000 (Jo
int Photographic Experts Group-2000) compressed video, IP next generation Internet protocol
An example of multicast distribution using v6 will be described.

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

Next, the operation and flow (1) to (7) will be described. (1) The distribution server 20 divides the video into four layers by resolution progressive. Each layer is, in order from the lowest quality layer, 80 × 60 (first layer), 160 × 120 (second layer), 320 × 240 (third layer), and 640 × 4.
It is 80 (fourth layer). At this time, the distribution server 2
The number 0 transmits the number of layers (4), the capability (resolution) required for each layer, and the identifier (arbitrary character string) of the stream distributed by itself to the address allocation server 30.

(2) The address allocation server 30 which has received these pieces of information receives four IPv6 multicast addresses, for example, ff18 :: 1234: 5678:
9abc: 0001 (first layer), ff18 :: 123
4: 5678: 9abc: 0002 (second layer), ff1
8 :: 1234: 5678: 9abc: 0003 (3rd
Layer), and ff18 :: 1234: 5678: 9ab.
c: 0004 (4th layer) is assigned. 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.

(3) Each of the three receiving terminals 10 (in this example, the mobile phone 10c) transmits its own IPv6 address to the address allocation server 30 together with the identifier of the stream distributed by the distribution server 20. To do.

(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.

(5) Terminal capability database server 40
Then, it retrieves the capability information corresponding to the identifier of the recipient A in these IPv6 addresses from its own database. As the search results, it is assumed that the resolution capability of the recipient A is 1024 × 768, the resolution capability of the recipient B is 160 × 120, and the resolution capability of the recipient A is 80 × 60. Then, the terminal capability database server 40 transmits the capability information as a result of these to the address allocation server 30.

(6) The address allocation server 30 which has acquired the terminal capability information searches the multicast address from the built-in address database 36 using the stream identifier and the capability information as keys. Then, one or a plurality of multicast addresses obtained as a result are transmitted to each receiving terminal 10 (in this example, the mobile phone 10c as a representative). For example, for recipient A,
Since the resolution capability of 1024x768 can tolerate all layers of the stream being delivered, ff18 :: 1234: 5
678: 9abc: 0001 (first layer), ff18 ::
1234: 5678: 9abc: 0002 (second layer),
ff18 :: 1234: 5678: 9abc: 0003
(Third layer), and ff18 :: 1234: 5678:
All addresses of 9abc: 0004 (4th layer) are transmitted.

(7) The distribution server 20 multicast-transmits the data of the corresponding layers (resolution components) to the groups represented by the four multicast addresses. On the other hand, each receiving terminal 10 (in this example, the mobile phone 10c as a representative) is assigned an address allocation server 30.
Participates in the multicast group informed by and receives the video from the distribution server 20.

With the above configuration, each receiving terminal 10 participates in the multicast group notified from the address allocation server 30 so that the quality of each receiving terminal 10 can be optimized without receiving unnecessary data. It becomes possible to receive video.

Although only the resolution is taken as the capability information of the receiving terminal in this embodiment, it is not specified in the present invention, and it is possible to realize a multicast hierarchical system according to various capability information. .

[0110]

As described above, since the distribution server and the receiving terminal are made to know the optimum multicast layer, the distribution server can transmit only the multicast data corresponding to the capability of the receiving terminal. The terminal can receive the image with the optimum quality for the capability of each receiving terminal without receiving unnecessary data.

[Brief description of drawings]

FIG. 1 is a principle diagram of a multicast hierarchical system of the present invention.

FIG. 2 is a functional block diagram showing processing functions of the receiving terminal of the present invention.

FIG. 3 is a functional block diagram showing processing functions of a distribution server of the present invention.

FIG. 4 is a functional block diagram showing processing functions of the address allocation server of the present invention.

FIG. 5 is a flowchart explaining the basic operation of the receiving terminal of the present invention.

FIG. 6 is a flowchart illustrating the basic operation of the distribution server of the present invention.

FIG. 7 is a flowchart illustrating the basic operation of the address allocation server of the present invention.

FIG. 8 is a flowchart illustrating the basic operation of the terminal capacity database server of the present invention.

FIG. 9 is a network sequence diagram for explaining the operation between the distribution server and the address allocation server of the present invention.

FIG. 10 is a network sequence diagram for explaining the operation between the receiving terminal, the address allocation server, and the terminal capability database of the present invention.

FIG. 11 is a network sequence diagram for explaining the operation between the distribution server and the receiving terminal of the present invention.

FIG. 12 is a network sequence diagram for explaining the operation between the distribution server and the address allocation server of the present invention.

FIG. 13 is an overall configuration diagram showing a specific example of a multicast hierarchical system of the present invention.

[Explanation of symbols]

1 ... Multicast hierarchical system, 10 ... Receiving terminal, 11, 11a to 11m ... Receiving unit, 12 ...
・ Processing unit, 13 ... Network interface, 2
0 ... Delivery server, 21, 21a to 21n ... Delivery unit, 22 ... Processing unit, 23 ... Network interface, 30 ... Address assignment server, 31 ...
..Registration unit, 32 ... Search unit, 33 ... Processing unit, 3
4 ... Inquiry section, 35 ... Network interface, 36 ... Address database, 40 ...
・ Terminal capability database server, 50 ... Network

Claims (10)

[Claims] 1. A multicast layered system for delivering layer-encoded stream data, transmitting multicast participation information, receiving an IP multicast address, and joining a multicast group based on the received IP multicast address. A receiving terminal, a delivery server that sends search information and receives the IP multicast address, a terminal ability database server that searches and sends corresponding capability information using the multicast participation information as a key, and the delivery server to the The search information is received, the multicast participation information is received from the receiving terminal, the multicast participation information is transmitted to the terminal capability database server, the searched capability information is received, and the IP multicast is transmitted from the address database. Multicast layered system characterized by having to search an address, the address allocation server for sending the multicast address to the receiving terminal and the distribution server, a. 2. The multicast layering system according to claim 1, wherein the search information is the number of layers, processing capability, and stream identifier. 3. The multicast hierarchical system according to claim 1, wherein the multicast participation information is a stream identifier and an IP address. 4. The address database searches the multicast address using a stream identifier and the capability information as a key.
The described multicast layering system. 5. A receiving terminal for confirming a network group to which the user belongs, comprising: a receiving unit for receiving multicast data, a processing unit for overall processing, and a network interface for performing communication via a network. And the receiving terminal. 6. The receiving terminal according to claim 5, wherein the receiving unit is subdivided into a plurality of receiving units to support a plurality of IP multicast addresses. 7. A distribution server that distributes information to a receiving terminal, comprising: a distribution unit that distributes multicast data, a processing unit that handles overall processing, and a network interface that performs communication via a network. Delivery server to do. 8. The distribution server according to claim 7, wherein the distribution unit is subdivided into a plurality of distribution units to correspond to a plurality of IP multicast addresses. 9. An address allocation server that sets each device address on a network, a registration unit that registers a request from a distribution host, a search unit that searches an IP multicast address, a processing unit that is responsible for overall processing, and a reception unit. An address assignment server, comprising: an inquiry unit for inquiring about the capability of a terminal, and a network interface for performing communication via a network. 10. A multicast layering method for delivering a layer-encoded service, wherein a device to which the service is delivered transmits multicast participation information, receives a fixed IP multicast address, and receives the IP multicast address. Participate in the multicast group based on the above, the device that distributes the service transmits the search information, receives the IP multicast address, and stores the capability information by using the multicast participation information as a key. To send the service to a device to which the service is distributed, and to perform address allocation by the device that receives the search information from the device that distributes the service, and from the device that distributes the service to the multicast After receiving the participation information, After transmitting the cast participation information to the device in which the capability information is stored, receiving the retrieved capability information, retrieving the multicast address, and providing the multicast address to the device that provides the service and the service. Multicast to a device that provides the service, the device that provides the service delivers data to the multicast address, and the device that provides the service receives data for the multicast address. Method.