JP2007173899A - Repeater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a repeater enabling computers subordinate to different private networks to perform communication with each other, without interposing another intermediary network address between the plurality of private networks. <P>SOLUTION: A protocol module 13b of a repeater 10 receives its Join message during the middle of transmitting the Join message in a PIM-SM from any of computers on a private network B to a computer of another private network B. In this case, a multicast management application 11b for the network B reads an IP address corresponding to a destination group address (DA) included in the Join message from a transfer destination management table 12b for the network B, and transmits the read IP address to a private network A through a protocol module 13a for the network A without returning the IP address to the private network B. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a relay device for relaying data exchanged between a plurality of networks.

  As is well known, since the private network has a unique address system that is different from the external network, there is a possibility that the same network address may be used repeatedly in a plurality of private networks. For this reason, it is not permitted to connect a plurality of private networks via a general relay device such as a router or a computer having such a function. This will be specifically described below.

  FIG. 13 is a configuration diagram of a conventional general relay device 90. As shown in FIG. 13, a conventional relay device 90 includes a plurality of network interfaces 90e and 90f, a CPU [Central Processing Unit] 90g, a DRAM [Dynamic Random Access Memory] 90h, and a storage 90i. The storage 90i stores several programs developed in the DRAM 90h. The program includes an application (program) 91 that transmits / receives data to / from an application of another terminal device, and a protocol module that controls packet input / output, packet generation, and data reproduction at a network interface ( Program) 92 is included.

  Here, as shown in FIG. 13, of the network interfaces 90e and 90f, the network interface 90e is connected to the two terminal devices E1 and E2 via the router E0, and the other network interface 90f is connected to the router. If it is connected to the terminal device F1 via F0, the path management table used by the protocol module 92 to determine the packet destination is associated with the network address of the terminal device E1 and the network address of the router E0. Records, a record in which the network address of the terminal device E2 is associated with the network address of the router E0, and a record in which the network address of the terminal device F1 is associated with the network address of the router F0 are stored.

  If the pair of networks E and F to which the conventional relay device 90 is connected are both private networks, the same network address is set in the terminal device E2 and the terminal device F1, as described above. There is a possibility of being. In such a case, even if the terminal device E1 tries to send data to the terminal device F1, the protocol module 92 refers to the route management table in order from the top using the network address designated as the destination as a key. When the order of the records is as shown in FIG. 13, the network address of the terminal device E2 is detected before that of the terminal device F1, so the terminal device E2 via the router E0. The data is sent to the terminal device F1, and the data does not reach the terminal device F1.

  Because of such unreasonableness, it is not permitted to connect a plurality of private networks E and F via a general relay device 90 such as a router or a computer having such a function.

JP 2005-244904 A

  Due to the above constraints, when communication is possible between terminal devices belonging to a plurality of private networks, a network such as the Internet is interposed as an intermediary between the private networks, and the intermediary network and the private network It was necessary to prepare a function such as NAT / IP masquerading that performs address translation between them.

  However, in such a connection form, communication with only one specific terminal device of the destination private network is possible, so there is a problem that a service such as multicast that provides data to many terminal devices cannot be operated. It was. In addition, even if the communication speed of the private network is high, if the communication speed of the mediation network is low, data cannot be communicated at high speed. For this reason, it has been desired by consumers to connect these private networks without interposing another network between the private networks.

  The present invention has been made in view of the problems of the prior art as described above, and the problem is that computers belonging to different private networks can mutually interact without interposing another intermediary network between the plurality of private networks. The purpose is to enable communication.

  The relay device devised to solve the above-mentioned problem is the information specifying the service providing destination in the private network and the service providing destination for each of the plurality of private networks having their own unique address system. A storage unit that associates and stores the address of the device, a plurality of network interfaces connected to each of the plurality of private networks via a router in the private network, Through any one of the devices in the private network connected to the network interface, a service including information specifying a service providing destination in a private network different from the private network is included. Receiving the service request information, and when the receiving unit receives the service request information, the address corresponding to the information specifying the service providing destination included in the received service request information is read from the storage unit, A transmission unit is provided that transmits the service request information through the network interface connected to a private network in which the address of the destination is set, with the read address as a destination.

  When configured in this way, if the reception unit receives the service request information while the service request information is being sent from a computer on any private network to a computer on a different private network, The address corresponding to the information specifying the service providing destination included in the service request information is read from the storage unit, and the read service request information is not sent back to the private network of the transmission source. It is automatically sent to the read address.

  Therefore, according to the present invention, computers belonging to different private networks can communicate with each other without interposing another intermediary network between the plurality of private networks.

  Next, two best modes for carrying out the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1

  FIG. 1 is a configuration diagram of a computer network system according to the first embodiment.

  The computer network system according to the first embodiment includes a private network A, a private network B, and a relay device 10.

  The private network A is a network in which a plurality of computers are communicably connected, and an address system independent of an external network is set for each computer. In the first embodiment, for the sake of explanation, it is assumed that the private network A includes at least two distribution server devices 21a and 22a and a router 23a. The two distribution server devices 21a and 22a are both computers for distributing multicast packets according to PIM-SM (Protocol Independent Multicast-Sparse Mode), and the router 23a functions as a rendezvous point (RP). Computer. Here, for the sake of explanation, a source address (DA) of 230.1.1.1 and a destination group address (SA) of 10.1.1.1 are set in the distribution server device 21a, and 230.2.1.1 is set in the distribution server device 22a. It is assumed that a source address (DA) of 10.2.1.1 and a destination group address (SA) of 10.2.1.1 are set, and an IP [Internet Protocol] address of 10.3.1.1 is set in the router 23a.

  On the other hand, the private network B is also a network in which a plurality of computers are communicably connected, and an address system independent of an external network is set for each computer. In the first embodiment, for the sake of explanation, it is assumed that the private network B includes at least three terminal devices 31b, 32b, 33b and a router 34b. The three terminal devices 31b, 32b, 33b are all commercially available personal computers, and the router 34b is a computer for relaying IP packets. Here, for the purpose of explanation, IP addresses 10.1.1.1, 10.2.1.1, and 10.3.1.1 are set for the three terminal devices 31b, 32b, and 33b, respectively, and an IP address of 10.4.1.1 is set for the router 34b. Is set.

  In the computer network system of the first embodiment, by connecting the router 23a of the private network A and the router 34b of the private network B to the relay device 10, respectively, two different private networks A and B are connected to the Internet or the like. Connected directly without going through another network.

  FIG. 2 is a configuration diagram of the relay apparatus 10.

  The relay device 10 is a computer that relays multicast packets exchanged between devices on the private network A and devices on the private network B according to PIM-SM between the networks A and B.

  This relay device 10 includes an A network interface (IF) 10a, a B network interface (IF) 10b, a CPU [Central Processing Unit] 10c, a DRAM [Dynamic Random Access Memory] 10d, and a storage 10e. Yes.

  Of these, the A IF 10a is connected to the router 23a of the private network A, and the B IF 10b is connected to the router 34b of the private network B. Further, the storage 10e stores several programs that are expanded in the DRAM 10d by the CPU 10c.

  The programs stored in the storage 10e control the input / output of packets in the application 11a that manages the destination of multicast packets from the private network A, the application 11b that manages the destination of multicast packets from the private network B, and the IF 10a for A. The protocol module 13a for A and the protocol module 13b for B which control the input / output of the packet in IF IF 10b for B are included.

  The two multicast management applications 11a and 11b both use the transfer destination management tables 12a and 12b in order to manage the destination of the multicast packet.

  FIG. 3 is a diagram illustrating an example of a data structure of the B transfer destination management table 12b.

  The transfer destination management table 12b for B has the same number of records as the destination group address set in the private network A. Each record has fields of “destination group address” and “A-side transfer destination address”. The “destination group address” field is a field in which each destination group address is recorded. The “A-side transfer destination address” field is a field in which the IP address of an upstream computer (router or distribution server device) to be a packet transfer destination when the destination group address is designated as a destination is recorded. is there.

  The transfer destination management table 12a for A is not shown, but the destination group address set in the private network B (not shown in the example shown in FIG. 1) is recorded in the “destination group address” field. At the same time, “A” in the name of the “A-side transfer destination address” field may be replaced with “B”, and the contents of this field may be changed as appropriate, and thus will not be described in detail here.

  Accordingly, the DRAM 10d and the storage 10e storing the transfer destination management tables 12a and 12b described above correspond to the storage unit described above.

  By the way, the program in the storage 10e is started by the CPU 10c when the main power of the relay device 10 is turned on. However, the Join message transmission / reception socket interface program included in the protocol modules 13a and 13b is not activated when the main power is turned on. Here, the Join message is a message transmitted to a rendezvous point by a terminal device that is intended to receive data multicast-distributed from the distribution server device 22a or the distribution server device 22b, or tries to run as a rendezvous point. A PIM-compatible router transmits a message to another rendezvous point or bootstrap router, and a specific message format is defined in RFC 2362 [Request for Comments 2362].

  FIG. 4 is a diagram showing a flow of processing executed by the CPU 10c in accordance with the B multicast management application 11b.

  After the start of the processing according to FIG. 4, the CPU 10c activates the join message receiving socket interface program for the protocol module 13b for B (step S101). As a result, the socket for receiving Join messages coming from the private network B is opened.

  Subsequently, the CPU 10c waits until the Join message receiving socket receives the Join message (step S102; NO). Accordingly, the CPU 10c executing this step S102 corresponds to the above-described receiving unit.

  Thereafter, when the Join message receiving socket receives the Join message (step S102; YES), the CPU 10c uses the destination group address in the [Encoded-Multicast Group Address] field in the header of the Join message as a key. The transfer destination management table 12b in FIG. 3 is searched (step S103).

  When the destination group address cannot be detected from the transfer destination management table 12b of FIG. 3 (step S104; NO), the CPU 10c discards the join message (step S105), and the join message reception socket receives the join message. It returns to the state which waits to do (step S102; NO).

  On the other hand, when the destination group address can be detected from the transfer destination management table 12b of FIG. 3 (step S104; YES), the CPU 10c activates the join message receiving socket interface program for the protocol module 13a for A (step S104). S106). As a result, the socket for sending a Join message to be sent to the private network A is opened.

  Subsequently, the CPU 10c performs a process of transmitting a Join message to the transfer destination address of the record detected from the transfer destination management table 12b of FIG. 3 through the Join message transmission socket (step S107).

  Therefore, the CPU 10c that executes steps S103, S104, and S107 corresponds to the transmission unit described above.

  After the transmission, the CPU 10c waits until the Join message receiving socket receives the Join message (step S108; NO). Therefore, this step S108 corresponds to the above-described receiving unit.

  After that, when the Join message receiving socket receives the Join message (step S108; YES), the CPU 10c searches the transfer destination management table 12b of FIG. 3 with the destination group address in the Join message, similarly to step S103. (Step S109).

  Thereafter, when the destination group address cannot be detected from the transfer destination management table 12b of FIG. 3 (step S110; NO), the CPU 10c discards the join message (step S111), and the socket for receiving the join message becomes the join message. Is returned to a state of waiting for reception (step S108; NO).

  On the other hand, when the destination group address can be detected from the transfer destination management table 12b of FIG. 3 (step S110; YES), the CPU 10c joins the transfer destination address of the record detected from the transfer destination management table 12b of FIG. The process for transmitting the Join message is performed through the message transmission socket (step S112), and the process returns to the state of waiting for the Join message reception socket to receive the Join message (step S108; NO).

  Therefore, the CPU 10c that executes steps S109, S110, and S112 corresponds to the transmission unit described above.

  Note that the transmission / reception socket opened by the processing according to FIG. 4 is closed when the main power supply of the relay device 10 is cut off or restarted.

  Since such processing is performed in the relay apparatus 10, a Join message is sent from any of the computers 31b to 34b on the private network B toward the rendezvous point in the private network A. When the Join message receiving socket by the B protocol module 13b receives the Join message (Step S102; YES), if the destination group address is appropriate (Steps S103, S104; YES), the Join by the A protocol module 13a is joined. The message transmission socket is opened (step S106), and the communication path of the Join message from the private network B to the private network A is established on the relay device 10.Thereafter, when a Join message addressed to an appropriate destination group address is sent from the private network B to the relay device 10, the relay device 10 automatically returns the Join message to the private network B without returning it. Therefore, it is sent to the private network A (step S108; YES, S109, S110; YES, S112).

  Therefore, according to the relay apparatus 10 of the first embodiment, the private networks A and B can freely communicate with each other regardless of whether the same network address is used in two different private networks A and B. Will be able to connect to.

Embodiment 2

  FIG. 5 is a configuration diagram of a computer network system according to the second embodiment.

  The computer network system according to the second embodiment includes a private network C, a private network D, and a relay device 60.

  The private network C is a network in which a plurality of computers are communicably connected, and an address system independent of an external network is set for each computer. In the second embodiment, for the sake of explanation, it is assumed that the private network C includes at least two web server devices 71c and 72c and a router 73c. The two web server devices 71c and 72c are both computers for transmitting web page data to the web client device according to HTTP [HyperText Transfer Protocol], and the router 73c is for relaying IP packets. It is a computer. Here, for the sake of explanation, the IP addresses 10.1.1.1 and 10.2.1.1 are set for the two web server devices 71c and 72c, respectively, and the IP address 10.3.1.1 is set for the router 73c. Shall.

  On the other hand, the private network D is also a network in which a plurality of computers are communicably connected, and an address system independent of an external network is set for each computer. In the second embodiment, for the sake of explanation, it is assumed that the private network D includes at least three web client devices 81d, 82d, and 83d and a router 84d. The three web client devices 81d, 82d, and 83d are all devices obtained by installing a web browser on a commercially available personal computer, and the router 84d is a computer for relaying IP packets. Here, for the sake of explanation, the IP addresses of 10.1.1.1, 10.2.1.1, and 10.3.1.1 are set to the three web client devices 81d, 82d, and 83d, respectively, and the IP of 10.4.1.1 is set to the router 84d. Assume that an address is set.

  In the computer network system of the second embodiment, by connecting the router 73c of the private network C and the router 84d of the private network D to the relay device 60, two different private networks C and D are connected to the Internet or the like. Connected directly without going through another network.

  FIG. 6 is a configuration diagram of the relay device 60.

  The relay device 60 is a computer that relays an HTTP message unicast between a device on the private network C and a device on the private network D between the networks C and D.

  The relay device 60 includes a C network interface (IF) 60c, a D network interface (IF) 60d, a CPU 60e, a DRAM 60f, and a storage 60g.

  Among these, the C IF 60c is connected to the router 73c of the private network C, and the D IF 60d is connected to the router 84d of the private network D. In addition, the storage 60g stores several programs that are expanded in the DRAM 60f by the CPU 60e.

  The programs stored in the storage 60g include an application 61 that manages the destination of unicast packets between the private networks C and D, a protocol module 63c for D that controls input / output of packets in the C IF 60c, and a protocol in the IF 60d for D. A D protocol module 63d for controlling packet input / output is included.

  The unicast management application 61 uses the C transfer destination management table 62c in order to manage the destination of the HTTP message from the private network C to the private network D. Further, the unicast management application 61 uses the D transfer destination management table 62d in order to manage the destination of the HTTP message from the private network D to the private network C.

  FIG. 7 is a diagram showing an example of the data structure of the D transfer destination management table 62d.

  Each record of the D transfer destination management table 62d has fields of “request destination address”, “first path”, and “C side transfer destination address”. In the “request destination address” field, among the unused (unset) IP addresses in the private network D, the web server devices 71c and 72c or the web client devices in the private network C (in the example shown in FIG. 5) This is a field in which an IP address virtually allocated to (No) is recorded. In the second embodiment, for the sake of explanation, the web server device 71c is virtually assigned an unused IP address of 10.5.1.1 in the private network D, and the web server device 72c has It is assumed that an unused IP address 10.5.1.2 is virtually allocated in the private network D. As a result, the web client devices 81d to 83d in the private network D must send a request message to 10.5.1.1 or 10.5.1.2 when requesting a web page from the web server devices 71c and 72c of the private network C. The “first path” field is a field in which path information incorporated as the first path in the URL [Uniform Resource Locator] set in each web page of the web server devices 71c and 72c is recorded. However, since the web client device (not shown in the example shown in FIG. 5) does not have a web page, the “first pass” field is blank for a record of such a device. In the “C-side transfer destination address” field, the IP addresses of the web server devices 71c and 72c in the private network C (IP addresses in the private network C) are recorded.

  Although the transfer destination management table 62c for C is not shown in the drawing, the “request destination address” field of the table 62c contains an IP address that is not used in the private network C and each web in the private network D. Record what is virtually allocated to the client devices 81d to 83d, and replace “C” in the name of the “C-side transfer destination address” field with “D” and this field and the “first path” field. Since the contents of the above may be changed as appropriate, they will not be described in detail here.

  Accordingly, the DRAM 60f and the storage 60g that store the transfer destination management tables 62c and 62d described above correspond to the storage unit described above.

  By the way, the program in the storage 60g is activated by the CPU 60e when the main power of the relay device 60 is turned on. However, the HTTP message transmission / reception socket interface program included in the protocol modules 63c and 63d is not activated when the main power is turned on, as in the first embodiment.

  8 and 9 are diagrams showing a flow of processing executed by the CPU 60e in accordance with the unicast management application 61.

  8 and 9, the CPU 60e activates an HTTP message receiving socket interface program for the C protocol module 63c (step S201). As a result, a socket for receiving an HTTP message coming from the private network C is opened.

  In addition, the CPU 60e activates the HTTP message reception socket interface program for the D protocol module 63d (step S201). As a result, a socket for receiving an HTTP message coming from the private network D is opened.

  Subsequently, the CPU 60e waits until the reception socket of the C or D protocol module 63c, 63d receives the HTTP message (step S202; NO). Therefore, the CPU 60e executing this step S202 corresponds to the above-described receiving unit.

  Thereafter, when the receiving socket for C or D receives the HTTP message (step S202; YES), the CPU 60e determines whether the HTTP message is from private network C or private network D (for C). (Which of the receiving socket for C and the receiving socket for C has been received) is discriminated (step S203).

  If the HTTP message is from the private network D (step S203; YES), the CPU 60e sends the IP address of the destination acquired from the D protocol module 63d that received the HTTP message, If the HTTP message is a request message, the D transfer destination management table 62d is further searched using the path information included as the first path in the GET method as a key (step S204).

  If a record that matches the condition cannot be detected from the D transfer destination management table 62d (step S205; NO), the CPU 60e sends an error message as shown in FIG. 10 to the transmission source in the private network D. Processing for transmission is performed (step S206), and the state returns to a state of waiting for the reception socket for C or D to receive the HTTP message (step S202; NO).

  On the other hand, when a record that matches the condition can be detected from the D transfer destination management table 62d (step S205; YES), the CPU 60e activates a socket interface program for receiving an HTTP message to the C protocol module 63c. (Step S207). As a result, a socket for sending an HTTP message to be sent to the private network C is opened.

  Subsequently, the CPU 60e performs a process of transmitting an HTTP message to the transfer destination address of the record detected from the D transfer destination management table 62d through the C message transmission socket (step S208). If this HTTP message is a request message as shown in FIG. 11, the CPU 60e sends a path in the GET method of the HTTP message before sending the HTTP message in step S208 as shown in FIG. Processing for rewriting the host information is also performed.

  Therefore, the CPU 60e that executes steps S204, S205, and S208 corresponds to the transmission unit described above.

  After the transmission, the CPU 60e waits for the C or D receiving socket to receive the HTTP message (step S213; NO).

  If the HTTP message received in step S202 is from the private network C (step S203; NO), the CPU 60e sends the IP address of the transmission destination acquired from the C protocol module 63c that received the HTTP message. If the address and the HTTP message is a request message, the C transfer destination management table 62c is searched using the path information included as the first path in the GET method as a key (step S209).

  If a record that matches the conditions cannot be detected from the C transfer destination management table 62c (step S210; NO), the CPU 60e sends an error message as shown in FIG. 10 to the transmission source in the private network C. Processing for transmission is performed (step S206), and the state returns to a state of waiting for the reception socket for C or D to receive the HTTP message (step S202; NO).

  On the other hand, if a record that matches the condition can be detected from the C transfer destination management table 62c (step S210; YES), the CPU 60e causes the protocol module 63d for D to activate the socket interface program for receiving HTTP messages. (Step S211). As a result, a socket for sending an HTTP message to be sent to the private network D is opened.

  Subsequently, the CPU 60e performs a process of transmitting an HTTP message to the transfer destination address of the record detected from the C transfer destination management table 62c through the D message transmission socket (step S212). Similar to step S208, also in this step S212, when the HTTP message is a request message, the CPU 60e performs a process of rewriting the path and the host information in the GET method of the HTTP message before transmitting the HTTP message. .

  Therefore, the CPU 60e that executes steps S209, S210, and S212 corresponds to the transmission unit described above.

  After the transmission, the CPU 60e waits for the C or D receiving socket to receive the HTTP message (step S213; NO).

  While waiting for the reception of the HTTP message in step S213 (the execution subject of this process is equivalent to the receiving unit), when the C or D receiving socket receives the HTTP message (step S213; YES), the CPU 60e determines the HTTP message. Is from the private network C or the private network D (which one of the C reception socket and the C reception socket has been received) is determined (step S214).

  If the HTTP message is from the private network D (step S214; YES), the CPU 60e sends the destination IP address acquired from the D protocol module 63d that received the HTTP message, If the HTTP message is a request message, the D transfer destination management table 62d is further searched using the path information included as the first path in the GET method as a key (step S215).

  If a record that matches the conditions cannot be detected from the D transfer destination management table 62d (step S216; NO), the CPU 60e sends an error message as shown in FIG. 10 to the transmission source in the private network D. Processing to transmit is performed (step S217), and the state returns to a state of waiting for the reception socket for C or D to receive the HTTP message (step S213; NO).

  On the other hand, if a record that matches the conditions can be detected from the D transfer destination management table 62d (step S216; YES), the CPU 60e addresses the transfer destination address of the record detected from the D transfer destination management table 62d. A process of transmitting an HTTP message through the C message transmission socket is performed (step S218). As in step S208, also in this step S218, when the HTTP message is a request message, the CPU 60e performs a process of rewriting the path and the host information in the GET method of the HTTP message before transmitting the HTTP message. .

  Therefore, the CPU 60e that executes steps S215, S216, and S218 corresponds to the transmission unit described above.

  After the transmission, the CPU 60e waits for the C or D receiving socket to receive the HTTP message (step S213; NO).

  If the HTTP message received in step S213 is from the private network C (step S214; NO), the CPU 60e sends the destination IP acquired from the C protocol module 63c that received the HTTP message. If the address and the HTTP message is a request message, the C transfer destination management table 62c is searched using the path information included as the first path in the GET method as a key (step S219).

  If no record matching the condition is detected from the C transfer destination management table 62c (step S220; NO), the CPU 60e sends an error message as shown in FIG. 10 to the transmission source in the private network C. Processing to transmit is performed (step S217), and the state returns to a state of waiting for the reception socket for C or D to receive the HTTP message (step S213; NO).

  On the other hand, when a record matching the condition can be detected from the C transfer destination management table 62c (step S220; YES), the CPU 60e addresses the transfer destination address of the record detected from the C transfer destination management table 62c. A process of transmitting an HTTP message through the D message transmission socket is performed (step S221). As in step S208, also in this step S221, when the HTTP message is a request message, the CPU 60e performs processing for rewriting the path and the host information in the GET method of the HTTP message before transmitting the HTTP message. .

  Therefore, the CPU 60e that executes steps S219, S220, and S221 corresponds to the transmission unit described above.

  After the transmission, the CPU 60e waits for the C or D receiving socket to receive the HTTP message (step S213; NO).

  8 and 9 is closed when the main power supply of the relay device 10 is cut off or restarted.

  Since such processing is performed in the relay device 60, an HTTP message is sent from any of the web client devices 81d to 83d on the private network D to the web server devices 71c and 72c in the private network C. When the HTTP message receiving socket by the D protocol module 63d receives the HTTP message (step S202; YES), the destination is registered in the D transfer destination management table 62d (step S202). S204, S205; YES), the HTTP message transmission socket by the C protocol module 63c is opened (step S207), and the communication path of the HTTP message from the private network D to the private network C is established. The be established on the relay device 60. Thereafter, when an HTTP message addressed to the IP address registered in the transfer destination management table 62d for D is sent from the private network D to the relay device 60, the relay device 60 transmits the HTTP message to the relay device 60. The data is automatically sent to the private network C without returning to the private network D (steps S213; YES, S215, S216; YES, S218).

  Therefore, even if the same network address is used in two different private networks C and D by the relay device 60 of the second embodiment, the private networks C and D can freely communicate with each other. You can connect.

  In the second embodiment, the D transfer destination management table 62d shown in FIG. 7 includes the real addresses of the web server devices 71c and 72c and the private network for the web server devices 71c and 72c of the private network C. Although it has been described that the virtual address prepared in D is recorded in association with each other, the use of the D transfer destination management table 62d is not limited thereto.

  For example, in a record in which path information is recorded in the “first path” field, the real address in the private network C corresponding to the virtual address in the “request destination address” field is displayed in the “C-side transfer destination address” field. If different addresses are recorded, it is possible to impose access restrictions on the URL including the path information in the first path for the web client devices 81d to 83d in the private network D.

(Appendix 1)
A storage unit that stores, for each of a plurality of private networks, each having a unique address system, information specifying a service provider in the private network and an address of a device that is the service provider in association with each other;
A plurality of network interfaces connected to each of the plurality of private networks via a router in the private network;
Service request information including information for specifying a service providing destination in a private network different from the private network from a device in the private network connected to the network interface through any of the plurality of network interfaces. Receiving unit, and
When the receiving unit receives the service request information, the address corresponding to the information specifying the service providing destination included in the received service request information is read from the storage unit, and the read request address is used as the destination. A relay device comprising: a transmission unit that transmits a message through the network interface connected to a private network in which a destination address is set.

(Appendix 2)
The relay apparatus according to appendix 1, wherein the service request information is information requesting transmission of multicast data.

(Appendix 3)
The relay apparatus according to appendix 2, wherein the information specifying the service providing destination is a destination group address included in a Join message in PIM-SM.

(Appendix 4)
The relay apparatus according to appendix 1, wherein the service request information is information requesting transmission of unicast data.

(Appendix 5)
The storage unit stores, as information for specifying a service providing destination in a private network, an address that is unused in a private network different from the private network and virtually assigned to the service providing destination,
The transmission unit corresponds to the virtual address when the address included in the service request information received by the reception unit is an address virtually allocated to a service providing destination of another private address. A service provision destination address is read from the storage unit, and the service request information is transmitted through the network interface connected to a private network in which the destination address is set, using the read address as a destination. The relay device according to appendix 4.

(Appendix 6)
The transmitting unit is a case where the address included in the service request information received by the receiving unit is an address virtually allocated to a service providing destination of another private address, and the service request information is predetermined 6. The relay apparatus according to appendix 5, wherein the service request information is transmitted to an address different from the address of the service providing destination.

(Appendix 7)
Computer
For each of a plurality of private networks for which a unique address system is set, information for specifying a service providing destination in the private network and an address of a device that is the service providing destination are stored in a storage device in association with each other means,
From each of the plurality of private networks, a device in the private network connected to the network interface through any one of the plurality of network interfaces connected via the router in the private network. Receiving means for receiving service request information including information for specifying a service providing destination in a private network different from the private network; and
When the receiving means receives the service request information, an address corresponding to information for specifying a service providing destination included in the received service request information is read from the storage device, and the read request address is used as the destination. As a transmission means for transmitting through the network interface connected to the private network in which the destination address is set.

1 is a configuration diagram of a computer network system according to a first embodiment. Relay device configuration diagram The figure which shows an example of the data structure of the transfer destination management table for B The figure which shows the flow of a process by the multicast management application for B Configuration diagram of a computer network system according to the second embodiment Relay device configuration diagram The figure which shows an example of the data structure of the transfer destination management table for D Diagram showing the flow of processing by the unicast management application Diagram showing the flow of processing by the unicast management application Example of error message Example of request message addressed to virtual address of source network Example of request message addressed to real address of destination network Configuration of a conventional general relay device

Explanation of symbols

10 relay device 10a network interface for A 10b network interface for B 10c CPU
10d DRAM
11a Multicast management application for A 11b Multicast management application for B 12a Transfer destination management table for A 12b Transfer destination management table for B 13a Protocol module for A 13b Protocol module for B 21a Distribution server device 22a Distribution server device 23a Router 31b Terminal device 32b Terminal device 33b Terminal device 34b Router

Claims (5)

A storage unit that stores, for each of a plurality of private networks, each having a unique address system, information specifying a service provider in the private network and an address of a device that is the service provider in association with each other;
A plurality of network interfaces connected to each of the plurality of private networks via a router in the private network;
Service request information including information for specifying a service providing destination in a private network different from the private network from a device in the private network connected to the network interface through any of the plurality of network interfaces. Receiving unit, and
When the receiving unit receives the service request information, the address corresponding to the information specifying the service providing destination included in the received service request information is read from the storage unit, and the read request address is used as the destination. A relay device comprising: a transmission unit that transmits a message through the network interface connected to a private network in which a destination address is set. The relay apparatus according to claim 1, wherein the service request information is information requesting transmission of multicast data. The relay apparatus according to claim 1, wherein the service request information is information requesting transmission of unicast data. The storage unit stores, as information for specifying a service providing destination in a private network, an address that is unused in a private network different from the private network and virtually assigned to the service providing destination,
The transmission unit corresponds to the virtual address when the address included in the service request information received by the reception unit is an address virtually allocated to a service providing destination of another private address. A service provision destination address is read from the storage unit, and the service request information is transmitted through the network interface connected to a private network in which the destination address is set, using the read address as a destination. The relay apparatus according to claim 3. The transmitting unit is a case where the address included in the service request information received by the receiving unit is an address virtually allocated to a service providing destination of another private address, and the service request information is predetermined 5. The relay apparatus according to claim 4, wherein the service request information is transmitted to an address different from the service providing destination address.