JP2000341314A - Network system, information transmitting / receiving terminal, information providing device, and network construction method - Google Patents

Abstract

(57) [Problem] To prevent a heavy load on a network by connecting a client not connected to a multicast network to an optimal connection point to the multicast network. SOLUTION: A client 5 transmits connection request information and own location information to a server 2. The server 2 searches for a connection point at which the client 5 connects to the multicast network based on the position information of the client 5 received from the client 5 according to the connection request information received from the client 5. Then, the server 2 or the client 6 which is the connection point searched by the server 2 transmits the multicast data to the router 3 using the tunneling.
And / or to the client 5 via the router 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a network system, an information transmitting / receiving terminal, an information providing device, and a network construction method for transferring a multicast packet to an information transmitting / receiving terminal or the like in a network.

[0002]

2. Description of the Related Art In a conventional IP multicast network, a multicast packet is transferred using the following two methods.

In the first method, an information relay device (hereinafter, referred to as a router) of an IP network to which an information transmitting / receiving terminal (hereinafter, referred to as a client) belongs also serves as a multicast router. Like this first method,
There is no problem if the router is compatible with multicast, and if application software that supports multicast is used, multicast packets can be transmitted and received as they are.

In the second method, IPinIP encapsulation is performed on a multicast packet, so that the multicast packet subjected to the IPinIP encapsulation is passed through an IP unicast router that transfers only unicast packets. . Here, IPinIP encapsulation refers to encapsulating a multicast packet in a normal unicast packet. As in the second method, by using tunneling called a so-called encapsulated tunnel, an intermediate IP unicast router can handle a multicast packet as a unicast packet, and transmits and receives the encapsulated multicast packet. be able to. Note that IP multicast packets passing through the encapsulation tunnel are transmitted at the start point and the end point I.
P address is I of multicast router at both ends of tunnel
The feature is that it is a P address.

[0005]

However, most routers on the current Internet do not support multicasting, and access the multicast network by tunneling used in the second method. Is the most.

In the case of the second method, a program called a multicast router converts a multicast packet into a unicast packet and transfers the packet. And these multicast routers
They must know where to forward multicast packets as unicast packets. Therefore, when a different individual or organization constructs a multicast network, it is necessary to confirm not only the IP address but also each other's operation policies and countermeasures at the time of failure occurrence, and time and expertise are required. Required.

Accordingly, the present invention has been made in view of such circumstances, and by connecting an information transmission / reception terminal that is not connected to a multicast network to an optimal connection point to a multicast network, a great deal of networking is achieved. It is an object of the present invention to provide a network system, an information transmitting / receiving terminal, an information providing device, and a network construction method that do not apply a heavy load.

[0008]

In order to achieve the above-mentioned object, a network system according to the present invention provides a network system in which multicast data copied only to an information transmitting / receiving terminal requesting reception is transferred to a multicast network. The first is that the multicast data using tunneling for interconnecting networks corresponding to the networks is connected via an information relay device which is treated as unicast data directly transmitted from the information providing device to each information transmitting / receiving terminal. In the network system, wherein the information transmitting / receiving terminal constructs a network path for receiving the multicast data from the information providing apparatus that belongs to the multicast network and holds the multicast data or a second information transmitting / receiving terminal, The information transmitting and receiving terminal includes information transmitting means for transmitting connection request information for requesting connection to the multicast network and its own location information to the information providing apparatus, and the information providing apparatus transmits the information from the first information transmitting and receiving terminal A search for searching for a connection point at which the first information transmitting / receiving terminal connects to the multicast network based on position information of the first information transmitting / receiving terminal received from the first information transmitting / receiving terminal according to the received connection request information. The information providing apparatus or the second information transmitting / receiving terminal, which is a connection point searched by the search means, uses the tunneling to transmit the multicast data via the information relay apparatus to the first information. It is characterized by transmitting to a transmitting / receiving terminal.

In this network system, a first information transmitting / receiving terminal transmits connection request information for requesting connection to a multicast network and its own position information to an information providing apparatus, and the information providing apparatus transmits and receives the first information. In response to the connection request information received from the terminal, the first information transmitting / receiving terminal searches for a connection point at which the first information transmitting / receiving terminal connects to the multicast network based on the position information of the first information transmitting / receiving terminal received from the first information transmitting / receiving terminal. Then, the information providing device or the second information transmitting / receiving terminal, which is the connection point searched by the information providing device, transmits the multicast data to the first information transmitting / receiving terminal via the information relay device using tunneling.

Further, the information transmitting / receiving terminal according to the present invention is an information providing apparatus or a second information providing apparatus which belongs to a multicast network to which the duplicated multicast data is transferred only to the information transmitting / receiving terminal requesting reception and holds the multicast data. From the transmitting / receiving terminal, the multicast data is treated as unicast data which is directly transmitted from the information providing apparatus to each information transmitting / receiving terminal, wherein the multicast data using tunneling for interconnecting the networks corresponding to the multicast network is treated. In the information transmitting and receiving terminal receiving via the information relay device, information transmission means for transmitting connection request information requesting connection to the multicast network and its own location information to the information providing device, the tunneling is used, The serial multicast data, characterized in that it comprises an information receiving means for receiving through from the information providing apparatus or the second information transmitting and receiving terminals is a connection point which is searched by said information providing apparatus said information relaying apparatus.

In this information transmitting / receiving terminal, connection request information for requesting connection to the multicast network and its own position information are transmitted to the information providing apparatus, and the multicast data is searched by the information providing apparatus using tunneling. The information is received from the information providing device or the second information transmitting / receiving terminal, which is the connection point, via the information relay device.

Further, the information providing apparatus according to the present invention belongs to a multicast network in which the copied multicast data is transferred only to the information transmitting / receiving terminal requesting reception, and transmits the multicast data between networks corresponding to the multicast network. First information for requesting reception of the multicast data via an information relay device in which the multicast data using tunneling for interconnecting the information is handled as unicast data transmitted directly from itself to each information transmitting / receiving terminal In an information providing device for transmitting to a transmitting / receiving terminal, in response to connection request information for requesting connection to the multicast network received from the first information transmitting / receiving terminal,
Searching means for searching for a connection point at which the first information transmitting / receiving terminal connects to the multicast network based on the position information of the first information transmitting / receiving terminal received from the first information transmitting / receiving terminal; And transmitting the multicast data to the first information transmitting / receiving terminal via the information relay device.

[0013] In this information providing apparatus, in response to connection request information received from the first information transmitting / receiving terminal requesting connection to the multicast network, the first information transmitting / receiving terminal receives the information from the first information transmitting / receiving terminal. Based on the location information, the first information transmitting / receiving terminal searches for a connection point to connect to the multicast network, and transmits the multicast data to the first information transmitting / receiving terminal via the information relay device using tunneling.

Still further, the network construction method according to the present invention is directed to a tunneling for interconnecting networks corresponding to the multicast network to a multicast network to which the duplicated multicast data is transferred only to the information transmitting / receiving terminal requesting reception. Is connected via an information relay device which is treated as unicast data in which the multicast data used is directly transmitted from the information providing device to each information transmitting / receiving terminal.
Wherein the information transmitting / receiving terminal constructs a network path for receiving the multicast data from an information providing device that belongs to the multicast network and holds the multicast data or a second information transmitting / receiving terminal. The information transmitting / receiving terminal transmits connection request information requesting connection to the multicast network and its own position information to the information providing apparatus, and the information providing apparatus transmits the connection request information received from the first information transmitting / receiving terminal. The first information transmitting / receiving terminal searches for a connection point to connect to the multicast network based on the position information of the first information transmitting / receiving terminal received from the first information transmitting / receiving terminal, Information providing device or second information transmission / reception which is the searched connection point Terminal, using the tunneling, the multicast data, through the information relay apparatus characterized by constructing a path of the network received by the first information transmitting and receiving terminals.

In this network construction method, the first information transmitting / receiving terminal transmits connection request information for requesting connection to a multicast network and its own location information to the information providing apparatus, and the information providing apparatus transmits the first information In response to the connection request information received from the transmitting / receiving terminal, the first information transmitting / receiving terminal searches for a connection point to connect to the multicast network based on the position information of the first information transmitting / receiving terminal received from the first information transmitting / receiving terminal. The information providing device or the second information transmitting / receiving terminal, which is a connection point searched by the information providing device, uses the tunneling to transmit the multicast data to the first information transmitting / receiving terminal via the information relay device. Build a path for

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

A network system according to an embodiment to which the present invention is applied builds a system using, for example, the Internet. FIG. 1 shows a network system according to an embodiment to which the present invention is applied.

As shown in FIG. 1, the network system 1 includes an information providing device (hereinafter, referred to as a server) 2 and an information relaying device (hereinafter, referred to as a router) 3 belonging to a network A, and a router belonging to a network B. 4
And an information transmitting / receiving terminal (hereinafter, referred to as a client) 5 belonging to the network C. In the network system 1 in the initial state, IP (Internet Protocol)
l) It is assumed that a multicast network (hereinafter, referred to as a multicast network) is not constructed, and these devices are connected by a unicast network.

Here, IP multicast (hereinafter, referred to as multicast) means that a source server transfers information to only one or a plurality of clients requesting reception. Specifically, multicast means that a group address called class D (class D) is assigned to all clients subscribing to a specific group, and a router corresponding to multicast is automatically assigned only to a necessary destination. Refers to duplicating and transmitting data. Note that the class D address refers to a logical group address that exists only during operation of a group between Internet sites transmitting and / or receiving specific multicast data.

On the other hand, unicast means that the source server directly transmits information to each client on the receiving side. Specifically, unicast means that the source server duplicates the same number of data as the number of clients on the receiving side and transmits data one by one to each client on the receiving side as the destination. .

Next, each device provided in the network system 1 will be described.

The server 2 includes a central control unit 2a that operates based on a server program that supports multicasting, a multicast control unit 2b that constructs a network path so as to perform multicast communication with an external organization,
The system includes a database 2c in which multicast data and the like (hereinafter, referred to as multicast packets) are stored, and a communication unit 2d that mediates communication of information between the server 2 and the client 5.

The central control unit 2a includes, for example, a CPU (Centra
l Processing Unit) and operates based on a multicast-compatible server program stored inside. Specifically, the central control unit 2a sends a multicast control unit 2b, which is connected to a multicast control unit 5d to be described later as a multicast network by tunneling, to a multicast control unit 2b.
The multicast packet acquired from the database 2c is transmitted to the multicast control unit 5d via the communication unit 2d, the router 3, the router 4, and the communication unit 5f.

The multicast control unit 2b is, for example, a multicast router, and performs control based on a multicast program (hereinafter, referred to as mrouted) for controlling a route of a multicast packet stored therein. Specifically, the multicast control unit 2b, based on mrouted using a protocol used between the multicast routers such as IGMP (Internet Group Management Protocol) described later, for example, transmits information indicating how far the multicast packet has reached. Since it always checks with other multicast control units, it knows how far the multicast network has spread. That is, since the multicast control units provided in the server 2 and the client 5 always confirm where the other multicast control units exist, each multicast control unit determines where the other multicast control units exist. We always keep the information on what to do.

Also, the multicast control unit 2b
As shown in (1), according to the connection request information for requesting connection to the multicast network received from the client 5, which is the first client not connected to the multicast network, the multicast packet connected to the multicast network is held. The IP address of the server 2 or the client 6 which is the second client, and compares the recognized IP address with the IP address of the client 5. Based on the comparison result, the multicast network Server 2 or client 6 which is a connection point to the server is detected. That is, the multicast control unit 2b uses the optimum connection point search method described later to select a network closest to the client 5 in the network among the multicast control units that are currently distributing multicast packets in the existing multicast network. Search for the multicast control unit that is the connection point of Specifically, the multicast control unit 2b
By using mrinfo, an IP address at which the multicast control unit connected to the multicast network exists is listed, and among the listed 32-bit IP addresses, the IP address of the multicast control unit 5d is listed. A multicast control unit that distributes a multicast packet in a multicast network existing at the present time is a connection point to the multicast network closest to the client 5 in a multicast control unit that matches the most significant bits as much as possible. Judge. In addition,
This determination method is referred to as an optimal connection point search method.

Here, the IP address is a 32-bit information comprising a class from A to E, a network number for identifying a network, and a host number for identifying a host on the network. It is. Further, mrinfo indicates a location (I) where a multicast router connected to the multicast network exists.
(P address). Specifically, mrinfo includes mr provided in the multicast control unit which is a multicast router.
The information includes information such as an outgoing version number, information on how this multicast control unit is connected to another multicast control unit via a tunnel, information on a tunnel setting specification, and the like. By using this mrinfo, it is possible to obtain and display information on mrouted from either the multicast control unit in the network to which it belongs or the multicast control unit on the multicast network.

The database 2c stores multicast packets and the like that the server 2 distributes to the clients 5 and the like.

The communication unit 2d mediates information communication such as transmitting a multicast packet obtained from the database 2c by the multicast control unit 2b to the client 5, for example.

The routers 3 and 4 are devices for relaying data flowing on a network to another network, and when exchanging data via a plurality of networks, request the next router to transfer data. do. That is, the router 3 and the router 4 have a mechanism for mutually exchanging information on which network the network to which they belong is further connected to which network, and to the next router based on this information. And request data transfer. At least one of the routers 3 and 4 is a unicast-compatible router. In the network system 1, the router 3 and the router 4 both use unicast-compatible routers.

As described above with reference to FIG. 2, the client 5 is, for example, the first client 5 that is not connected to the multicast network.
Alternatively, the client 6 is a second client connected to the multicast network and holding the multicast data. The client 5 controls the functions of the input unit 5a to which information is input by a user operation, the output unit 5b for outputting information to be provided to the user, and the processing units such as the input unit 5a and the output unit 5b. A central control unit 5c, a multicast control unit 5d for determining whether or not a multicast packet can be received by IGMP to be described later, and a storage unit 5 for storing the multicast packet and the like received from the server 2.
e, and a communication unit 5f that mediates communication of information between the server 2 and the client 5. Client 6
Has the same function as the client 5.

The input unit 5a is a keyboard, a mouse, or the like. For example, the user can input information from the World Wide Web.
(Hereinafter, referred to as WWW.) By accessing the site, it is known that the server 2 is distributing the multicast packet, and if this user wishes to distribute the multicast packet from the server 2, the multicast from the server 2 is transmitted. Multicast packet distribution request information for requesting packet distribution is input by a user operation.

The output unit 5b is a display device such as a liquid crystal display and displays information based on the multicast packet received from the server 2.

The central control unit 5c is, for example, a CPU.
It operates based on a multicast-compatible application program stored inside. Specifically, the central control unit 5c activates a multicast-compatible application program based on multicast packet distribution request information, which will be described later, supplied from the input unit 5a.
A P message is issued in the network to which the client 5 belongs, and an attempt is made to receive the same multicast packet as the multicast packet distributed by the server 2 existing in this network.

Here, IGMP refers to a protocol for controlling a group of hosts configured to receive a multicast packet in multicast. This IGMP is used by routers to recognize the existence of members on sub-networks directly connected to them, and to make neighboring multicast controllers on a given network aware of participation in a specified host group. Is done. That is, IGMP is used for a host on a predetermined local subnetwork to make an adjacent multicast control unit recognize a multicast group to which the host belongs.

The multicast control unit 5d is, for example, a multicast router.
When the MP message is supplied, it is determined whether or not a multicast packet can be received by the IGMP. Further, the multicast control unit 5d includes multicast packet reception request information for requesting to receive the multicast packet and the multicast control unit 2b.
When the IP address information is supplied from the central control unit 5c, the multicast network connection request information, which is information for requesting connection to the multicast network, is transmitted to the network A as a unicast packet by performing IPinIP encapsulation. It transmits to the multicast control unit 2b of the server 2 to which it belongs.

Here, IPinIP encapsulation is
This refers to encapsulating a multicast packet in a normal unicast packet. FIG. 3 shows a configuration diagram of a message of an IPinIP encapsulated packet which is a packet subjected to the IPinIP encapsulation. This IPinIP encapsulated packet is, as shown in FIG. 3, a unicast packet composed of a unicast header area and a multicast packet area. Specifically, the unicast header area of the IPinIP encapsulated packet includes a destination address part A indicating the destination of the unicast packet which is the IPinIP encapsulated packet, and a source address part B indicating the source of the unicast packet. And a type field indicating information as to whether or not this unicast packet is really a multicast packet. The multicast packet area of the IPinIP encapsulated packet has a destination address portion C indicating the destination of the multicast packet.
, A source address D indicating the source of the multicast packet, and a multicast data part for storing the multicast data. And IPi
By using nIP encapsulation, that is, tunneling called a so-called encapsulated tunnel, an intermediate unicast router can handle a multicast packet as a unicast packet, and thus can transmit and receive the encapsulated multicast packet.

The storage unit 5e stores, for example, multicast packets and the like received from the server 2 via the router 3, the router 4, and the communication unit 5f.

The communication unit 5f mediates communication of information such that the multicast control unit 5d receives a multicast packet from the server 2, for example.

In the network system 1 configured as described above, the multicast control unit 2b of the server 2
In response to a request from the client 5, a multicast control unit closest to the network from the client 5 is searched for. The multicast control unit 5d connects to the found multicast control unit by tunneling. Then, the central control unit 5c causes the multicast control unit 5d to receive the multicast packet from the server 2.

Next, in the network system 1, the multicast control unit 2b of the server 2 searches the client 5 for the nearest multicast control unit in the network, and tunneling is performed between the found multicast control unit and the multicast control unit 5d of the client 5. Will be described with reference to the flowchart shown in FIG. 4 until the client 5 receives the multicast packet from the server 2.

As a premise, it is assumed that in the network system 1 in the initial state, no multicast network is constructed, and these devices are connected by a unicast network. Also, the multicast controller 2b, the router 3, the router 4, and the multicast controller 5
It is assumed that d is always operating. In the same network, at least one multicast control unit must be operating. For example, in the network system 1 shown in FIG.
b and the multicast control unit 5d must always operate. Further, the application program provided in the central control unit 5c of the client 5 includes the one in which the IP address of the multicast control unit 2b operating in the server 2 is input in advance by a user using a keyboard or the like. I do.

First, in step S1 in FIG. 4, the user accesses the WWW site and recognizes that the server 2 is delivering a multicast packet. When the requested multicast packet distribution request information is input using a keyboard or the like of the input unit 5a provided in the client 5, the central control unit 5c is supplied with the multicast packet distribution request information from the input unit 5a.

Subsequently, in step S2, the central control unit 5c starts a multicast-compatible application program according to the multicast packet distribution request information supplied from the input unit 5a. Central control unit 5c
Issues a normal IGMP message in the network C based on the started application program, supplies the message to the multicast control unit 5d here,
Attempt to receive the same multicast packet as the multicast packet distributed by server 2 existing in network C.

Subsequently, in step S3, the IGMP
The multicast control unit 5d to which the message is supplied,
It is determined whether the multicast packet can be received by the IGMP.

As described above, since no multicast network is constructed in the network system 1 in the flowchart shown in FIG. 4, the multicast control unit 5d is not connected anywhere as a multicast network. For this reason, since the IGMP message disappears in the network C, the multicast control unit 5d cannot receive the multicast packet distributed by the server 2. Accordingly, the central control unit 5c determines that the reception of the multicast packet is impossible, for example, by receiving the multicast packet non-reception information notifying that the multicast packet could not be received from the multicast control unit 5d. Therefore, the process proceeds to Step S4.

However, it is assumed that the multicast control unit 2b of the server 2 and the multicast control unit 5 of the client 5 in the network system 1 in the initial state described above.
d is connected as a multicast network, the multicast control unit 5 d
Can receive a multicast packet via a multicast network. Accordingly, in this case, the central control unit 5c determines that the multicast packet can be received, for example, by supplying the multicast packet reception information indicating that the multicast packet can be received from the multicast control unit 5d. Therefore, the process proceeds to step S7.

In step S4, the central control unit 5c supplied with the multicast packet non-reception information from the multicast control unit 5d receives the multicast packet reception request information requesting to receive the multicast packet from the server 2, and the multicast control unit 2b. IP
The address information is supplied to the multicast control unit 5d. The multicast control unit 5d supplied with the multicast packet reception request information and the IP address information from the central control unit 5c performs IPinIP encapsulation on the multicast network connection request information which is information requesting connection to the multicast network. Communication unit 5f as a unicast packet
To the multicast controller 2b via the router 4, the router 3, and the communication unit 2d.

Subsequently, in step S5, the multicast control unit 2b, which has received the multicast network connection request information from the multicast control unit 5d, uses the above-described optimal connection point search method to transmit the multicast packet in the multicast network existing at the present time. A multicast control unit that is the connection point to the multicast network closest to the client 5 in terms of the network is searched for among the multicast control units being distributed.

Specifically, the multicast control unit 2b
Uses mrinfo to list the IP addresses where the multicast control unit connected to the multicast network exists, and among the listed 32-bit IP addresses, the IP address of the multicast control unit 5d The one that matches as much as possible from the upper bits of the address is the connection point to the multicast network closest to the client 5 in the multicast control unit that is currently distributing the multicast packet in the existing multicast network. Judge as the multicast control unit. Here, the multicast control unit 2b determines that it is the connection point to the multicast network closest to the client 5 in terms of the network.

When it is expected that it takes time for the multicast control unit 2b to find the multicast control unit closest to the client 5 on the network, or when it is necessary to use a specific multicast control unit, You may set beforehand to select from several multicast control parts.

Subsequently, in step S6, the multicast control unit 2b, which determines that the connection point to the multicast network closest to the client 5 in the network is itself, prepares to connect with the multicast control unit 5d as the multicast network. Issues connection preparation request information requesting to perform the connection preparation to itself. Multicast control unit 2b receiving this issuance
Prepares to receive connection request information for requesting connection as a multicast network from the multicast control unit 5d via the communication unit 5f, the router 4, the router 3, and the communication unit 2d. When the preparation for receiving the connection request information is completed, the multicast control unit 2b
knowledgement), the communication unit 2d, router 3 and router 4
And to the multicast control unit 5d via the communication unit 5f.

Upon receiving the ACK from the multicast control unit 2b, the multicast control unit 5d connects to the multicast control unit 2b ready for connection by tunneling as a multicast network.

Subsequently, in step S7, the central control unit 2a transmits the multicast packet obtained from the database 2c to the multicast control unit 5b, which is connected to the multicast control unit 5d by tunneling as a multicast network, and transmits the multicast packet obtained from the database 2c to the And the multicast control unit 5d via the router 4 and the communication unit 5f. Then, the multicast control unit 5d
Supplies the received multicast packet to the central control unit 5c. Finally, the central control unit 5c supplies the supplied multicast packet to the storage unit 5e and stores it. Alternatively, by supplying the supplied multicast packet to the output unit 5b, the central control unit 5c causes the output unit 5b to output information obtained from the supplied multicast packet.

By performing the above processing, the client 5 connects to the nearest multicast control unit 2b in terms of network by tunneling as a multicast network.
Can receive a multicast packet.

In the above-described series of processing using the flowchart shown in FIG. 4, the multicast control unit 5d is provided inside the client 5, but if the IP address where the multicast control unit 5d exists is known, the process is terminated. As in the network system 10 shown in FIG. 5, the clients may be divided into a client 15 having no multicast control unit 5d and a client 16 having the multicast control unit 5d. Also,
In the series of processing using the flowchart shown in FIG. 4 described above, the multicast control unit 2b is provided inside the server 2, but if the IP address where the multicast control unit 2b exists is known, the network system shown in FIG. As shown in FIG. 20, the server is connected to the multicast controller 2
b may be divided into a server 21 having no multicast control unit 2b and a server 22 having the multicast control unit 2b. Furthermore, in the series of processes using the flowchart shown in FIG. 4 described above, the multicast control unit 2b and the multicast control unit 5d are provided inside the server 2 and the client 5, respectively. IP where multicast controller 5d exists
If the addresses are known, as in the network system 30 shown in FIG. 7, the server and the client are divided into a server 31 having no multicast control unit 2b, a server 32 having the multicast control unit 2b, and a multicast control unit. The client 35 having no 5d may be divided into the client 36 having the multicast control unit 5d.

Further, in the series of processing using the flowchart shown in FIG. 4 described above, only two multicast control units having mrouted, the multicast control unit 2b and the multicast control unit 5d, are shown. By providing a multicast control unit or the like having mrouted3 downstream of the multicast control unit 5d on the network for the unit 2b, when the multicast control unit 5d receives connection request information from the multicast control unit having mrouted3 downstream, The multicast network may be expanded recursively.

Further, in a series of processing using the flowchart shown in FIG. 4, a part of the route of the multicast network constructed through the above-described processing is set to TTL.
(Time To Live) value or the like may be used to make the data disappear after a certain period of time. Alternatively, when the multicast control unit stops operating, or when the computer or the like on which the multicast control unit is operating leaves the multicast network, a part of the route of the multicast network constructed through the above-described processing. May disappear after a certain period of time. Then, in the network system 1 in which the reception of the multicast packet cannot be performed due to the disappearance of a part of the route of the multicast network in this manner, the above-described processing is performed again to configure the optimal multicast network at that time. You may do it again.

As described above, in the network system 1 according to the embodiment to which the present invention is applied, even if the client belongs to a network not connected to the multicast network, the multicast network is automatically constructed. Thus, a multicast packet can be received from a server or the like belonging to the multicast network.

Further, even a user who is not familiar with multicast can automatically receive a multicast packet without imposing a large load on the network because the multicast network is automatically constructed.

Further, since the multicast network is automatically constructed, and a part of the route of the multicast network is automatically deleted, the user does not need to manage the multicast network.

Further, since the user can freely participate in the multicast network using the client, the number of applications corresponding to the multicast increases, and the traffic on the Internet congested by the current unicast service can be reduced.

Further, when a client belonging to a predetermined network receives a multicast packet from a server, another client belonging to the same network as the predetermined network also receives the same multicast packet from a client belonging to the predetermined network. be able to.

Furthermore, since the multicast network can be recursively expanded, it is possible to prevent a concentration of multicast packet acquisition requests to the server. That is, if there is a client that is receiving a multicast packet that the user wants to receive near a client that the user possesses, the multicast packet is received from this client, thereby burdening the server with a network upstream. Multicast packets can be received without calling.

In the network system 1, when a client close to the network to which the multicast control unit makes a request to receive a multicast packet from the server 2, the multicast control unit additionally connects to the client by tunneling. To transfer the multicast packet.

[0065]

As described above, according to the network system, the information transmitting / receiving terminal, the information providing apparatus and the network construction method according to the present invention, a multicast network is automatically constructed, so that a great load is imposed on the network. Multicast data can be received without calling.

According to the network system, the information transmitting / receiving terminal, the information providing apparatus and the network construction method according to the present invention, the multicast network is automatically constructed, and a part of the route of the multicast network disappears automatically. Therefore, the operator does not need to manage the multicast network.

Further, according to the network system, the information transmitting / receiving terminal, the information providing apparatus and the network construction method according to the present invention, when the information transmitting / receiving terminal belonging to the predetermined network receives the multicast data from the information providing apparatus, the predetermined network Other information transmission / reception terminals belonging to the same network can also receive the same multicast data from the information transmission / reception terminals belonging to the predetermined network.

Further, according to the network system, the information transmitting / receiving terminal, the information providing apparatus and the network construction method according to the present invention, the multicast network can be recursively expanded, so that the multicast data can be obtained by the information providing apparatus. Requests can be prevented from being concentrated. That is, if there is an information transmitting / receiving terminal that is receiving multicast data that the operator desires to receive near the information transmitting / receiving terminal owned by the operator, the information providing device is received by receiving the multicast data from the information transmitting / receiving terminal. Multicast data can be received without imposing a burden on the network upstream.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a network system showing an embodiment to which the present invention is applied.

FIG. 2 is a configuration diagram of a network system showing another embodiment to which the present invention is applied.

FIG. 3 shows an IP used in the embodiment to which the present invention is applied.
FIG. 4 is a packet configuration diagram showing a configuration of a message of an inIP encapsulated packet.

FIG. 4 is a diagram illustrating a series of processing from when a multicast control unit of a server searches for a multicast control unit closest to a network from a client to when a client receives a multicast packet from a server in an embodiment to which the present invention is applied; It is a flowchart which shows a flow.

FIG. 5 is a configuration diagram of a network system showing another embodiment to which the present invention is applied.

FIG. 6 is a configuration diagram of a network system showing another embodiment to which the present invention is applied.

FIG. 7 is a configuration diagram of a network system showing another embodiment to which the present invention is applied.

[Explanation of symbols]

1 network system, 2 servers, 3 routers,
4 routers, 5 clients

Claims (16)

[Claims] The present invention provides information to a multicast network to which copied multicast data is transferred only to an information transmitting / receiving terminal requesting reception by using tunneling for interconnecting networks corresponding to the multicast network. A first information transmission / reception terminal connected via an information relay device treated as unicast data transmitted directly from the device to each information transmission / reception terminal holds the multicast data belonging to the multicast network and holding the multicast data In a network system for constructing a route of a network for receiving information from an information providing apparatus or a second information transmitting / receiving terminal, the first information transmitting / receiving terminal may include connection request information for requesting connection to the multicast network. And information transmission means for transmitting the position information of the first information transmitting and receiving apparatus to the information providing apparatus, wherein the information providing apparatus receives from the first information transmitting and receiving terminal according to the connection request information received from the first information transmitting and receiving terminal. Search means for searching for a connection point at which the first information transmission / reception terminal connects to the multicast network based on the obtained position information of the first information transmission / reception terminal, and providing information as the connection point searched by the search means A network system, wherein a device or a second information transmitting / receiving terminal transmits the multicast data to the first information transmitting / receiving terminal via the information relay device using the tunneling. 2. The information transmitting means, according to information that the information providing device is distributing the multicast data, includes multicast data reception request information for requesting reception of the multicast data from the information providing device. 2. The network system according to claim 1, wherein the network system transmits connection request information for requesting connection to the multicast network and its own location information to the information providing device by being supplied. 3. The first information transmission / reception terminal includes operation input means for inputting reception request information for requesting reception of the multicast data, and the information transmission means receives the reception request information from the operation input means. 2. The network system according to claim 1, wherein the connection request information and the position information are transmitted to the information providing device when the information is supplied. 4. The search means, according to connection request information received from the first information transmitting / receiving terminal, an IP (Internet Protocol) of an information providing apparatus or a second information transmitting / receiving terminal connected to the multicast network. A) recognizing means for recognizing the address, the IP address recognized by the recognizing means, and the I
A comparison unit that compares the P address with a P address; and a detection unit that detects an information providing device or a second information transmitting / receiving terminal that is a connection point to the multicast network based on a comparison result compared by the comparison unit. The information providing device or the second information transmitting / receiving terminal, which is the connection point detected by the detecting means, transmits the multicast data using the tunneling via the information relay device to the first information transmitting / receiving terminal. The network system according to claim 1, wherein the transmission is performed to the network system. 5. The information providing apparatus according to claim 1, further comprising: a path eliminating unit that eliminates a path of a network connected by the first information transmitting / receiving terminal when a predetermined condition is satisfied. The described network system. 6. An information providing apparatus or a second information transmitting / receiving terminal that belongs to a multicast network to which the multicast data copied is transferred only to the information transmitting / receiving terminal requesting reception and that holds the multicast data. Information received through an information relay device in which the multicast data using tunneling interconnecting networks corresponding to the multicast network is treated as unicast data transmitted directly from an information providing device to each information transmitting / receiving terminal An information transmitting means for transmitting connection request information for requesting connection to the multicast network and its own location information to the information providing apparatus; and the tunneling is used to transmit the multicast data to the transmitting / receiving terminal. Information receiving terminal, characterized in that from the information providing apparatus or the second information transmitting and receiving terminals is a connection point searched by the providing apparatus and an information receiving means for receiving through the information relay apparatus. 7. The information transmitting means according to the information that the information providing device is distributing the multicast data, wherein the multicast data receiving request information for requesting to receive the multicast data from the information providing device is provided. 7. The information transmitting / receiving terminal according to claim 6, wherein the information transmitting / receiving terminal transmits connection request information requesting connection to the multicast network and its own location information to the information providing device when supplied. 8. An operation input means for inputting reception request information for requesting reception of the multicast data, wherein the information transmission means receives the reception request information from the operation input means, so that the connection is established. 7. The information transmitting / receiving terminal according to claim 6, wherein the request information and its own position information are transmitted to the information providing device. 9. A multicast network belonging to a multicast network to which copied multicast data is transferred only to an information transmitting / receiving terminal requesting reception, and tunneling for interconnecting the multicast data between networks corresponding to the multicast network is used. An information providing apparatus for transmitting the multicast data to a first information transmitting / receiving terminal requesting reception of the multicast data via an information relay apparatus which is treated as unicast data transmitted directly from the information transmitting / receiving terminal to itself; Responding to connection request information requesting connection to the multicast network received from the first information transmitting / receiving terminal, based on the position information of the first information transmitting / receiving terminal received from the first information transmitting / receiving terminal. First information transmitting / receiving end Comprises searching means for searching for a connection point connected to the multicast network, wherein the multicast data is transmitted to the first information transmitting / receiving terminal via the information relay device using the tunneling. Information providing device. 10. The search means, according to the connection request information received from the first information transmitting / receiving terminal, an IP (Internet Protocol) of an information providing apparatus or a second information transmitting / receiving terminal connected to the multicast network. )
Recognizing means for recognizing an address, comparing means for comparing the IP address recognized by the recognizing means with the IP address of the first information transmitting / receiving terminal, and based on a comparison result compared by the comparing means, An information providing device which is a connection point to the multicast network or a second
Detecting means for detecting said information transmitting / receiving terminal, wherein said multicast data is transmitted to said first information transmitting / receiving terminal via said information relay device using said tunneling. Information providing device. 11. The information providing apparatus according to claim 9, further comprising a route disappearing unit that disappears a route of a network connected by the first information transmitting / receiving terminal when a predetermined condition is satisfied. 12. A method for providing information to a multicast network to which copied multicast data is transferred only to an information transmitting / receiving terminal requesting reception by using tunneling for interconnecting networks corresponding to the multicast network. A first information transmission / reception terminal connected via an information relay device treated as unicast data transmitted directly from the device to each information transmission / reception terminal holds the multicast data belonging to the multicast network and holding the multicast data In a network construction method for constructing a route of a network to be received from an information providing device or a second information transmitting / receiving terminal, the first information transmitting / receiving terminal may include a connection request information requesting connection to the multicast network. And transmitting its own location information to the information providing device, the information providing device responding to the connection request information received from the first information transmitting / receiving terminal, and receiving the first information received from the first information transmitting / receiving terminal. The first information transmitting / receiving terminal searches for a connection point connected to the multicast network based on the position information of the transmitting / receiving terminal, and the information providing device or the second information transmitting / receiving terminal being the connection point searched by the information providing device Comprises constructing a network path for receiving the multicast data by the first information transmitting / receiving terminal via the information relay device using the tunneling. 13. The information transmitting / receiving terminal, according to the information that the information providing device is distributing the multicast data, the multicast data reception request information requesting to receive the multicast data from the information providing device. 13. The network construction method according to claim 12, wherein when supplied, connection request information requesting connection to the multicast network and its own location information are transmitted to the information providing apparatus. 14. The information providing apparatus as the connection point or the first information transmitting / receiving terminal connected to the second information transmitting / receiving terminal transmits the multicast data to the information providing apparatus or the second information transmitting / receiving terminal as the connection point. 13. The network according to claim 12, wherein the received multicast data is received from the information transmitting / receiving terminal via the information relay device, and the received multicast data is transferred to the third information transmitting / receiving terminal via another information relay device. How to build. 15. The information providing apparatus according to claim 1, wherein said information providing apparatus is connected to said multicast network in response to connection request information received from said first information transmitting / receiving terminal. Protoco
l) Recognizing the address, comparing the recognized IP address with the IP address of the first information transmitting / receiving terminal,
An information providing device or a second information transmitting / receiving terminal which is a connection point to the multicast network is detected based on the comparison result, and the information providing device or the second information providing device which is the connection point detected by the information providing device 13. The network construction method according to claim 12, wherein the second information transmitting / receiving terminal transmits the multicast data to the first information transmitting / receiving terminal via the information relay device using the tunneling. 16. The network construction method according to claim 12, wherein the information providing device deletes a route of a network connected by the first information transmitting / receiving terminal when a predetermined condition is satisfied. .