JP2018148264A - Terminal device, network module relay device, data relay device, and data communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable live transmission of predetermined data between each terminal device to be interconnected, and to easily switch a communication destination related to data transmission such as live video without changing the communication setting of each terminal device to be connected. It provides a terminal device, a network module relay device, a data relay device, and a data communication system that enable it. SOLUTION: A data communication system 1 of the present invention configures a terminal device so as to have an IP address included in a range of public local addresses according to a predetermined module basic information, and sets a common address for the module basic information. A set of terminal devices grouped by the above is configured as a network module. The connection between the network modules is performed by the data relay device 40-1, 40-2 using the mapping information based on the module basic information. [Selection diagram] Fig. 1

Description

  The present invention is capable of switching the destination of data transmission such as live video, a terminal device that communicates using an IP (Internet Protocol) packet, a network module relay device that interconnects each terminal device via an IP network, and data The present invention relates to a relay device and a data communication system.

In production and transmission of a television program, it is necessary to exchange data such as video signals and audio signals handled by a video recorder, a studio, etc., between terminal devices.

(Matrix switcher)
Therefore, as a terminal device for transmitting video signals, each device is not connected directly but via a matrix switcher so that the combination of the video output device on the transmission side and the video input device on the reception side can be easily changed. Connect. An example of connection using the matrix switcher 100 is shown in FIG. The matrix switcher 100 connects an image output device to be connected to a signal line of the image input device among the image output devices A to D and the image input devices E to G by using an electrical or mechanical switch (cross point). By doing so, it is possible to control the flow path of the video signal and switch the communication partner (see, for example, Patent Document 1).

(IP video switcher)
Also, an IP video switcher is known as a device for controlling the flow path of a video signal using IP network equipment (for example, Ethernet (registered trademark) switch) such as a layer 2 switch instead of an electrical or mechanical switch. (For example, refer to Patent Document 2). The IP video switcher converts a video signal into an IP packet, thereby making it possible to use general-purpose and inexpensive IP network equipment.

(IP video system)
Video signals are input / output in a conventional video output device or video input device by transmitting a non-packet format signal such as a synchronous digital signal or an analog electric signal through a coaxial cable.

  On the other hand, a video output device (hereinafter referred to as a “transmission terminal”) or a video input device (hereinafter referred to as a “reception terminal”) converts a video signal from an IP video switch to an IP packet in an IP video switcher and a video from the IP packet By providing a signal conversion function, video signals can be obtained using high-speed devices and routers used in IP networks such as 10 Gigabit Ethernet (registered trademark) and 40 Gigabit Ethernet (registered trademark) instead of coaxial cables. Can be transmitted. Such a system that transmits data such as video signals via an IP network is hereinafter referred to as an “IP video system”. In the IP video system, it is extremely easy to multiplex and transmit a plurality of video signals on one transmission cable, and a reduction in the number of cables required for signal transmission can be expected.

  In addition to indoor connections, video can also be transmitted using Internet connection services such as LTE (Long Term Evolution), WiMax (Worldwide Interoperability for Microwave Access), and public wireless LAN (Local Area Network). It becomes possible. For example, in the data communication system 200 using the Internet connection service shown in FIG. 11, the video is transmitted from the terminal device 11-1 at the relay site serving as an outdoor transmission point via the router 40-1, and the IP network 50 over the Internet. , The video can be received by the terminal device 11-2 at a reception point in another area such as a studio via the router 40-2.

(Switching communication partner in IP video system)
In an IP network, information such as a destination IP address and a source IP address recorded in a header portion of a packet is read, a packet transfer destination is determined based on routing information set in the router, and the packet is transferred. Therefore, in the IP video system, it is necessary to change packet header information or router routing information in order to switch communication partners.

(Unicast)
The most common and simple method as a data communication system is a method using unicast communication. The communication partner is switched at the transmitting terminal, and the destination IP address of the IP packet to be transmitted is changed to the IP address of the new receiving terminal. In this method, it is not necessary to change the routing information of the router, but it is necessary to change the communication setting of the transmitting terminal.

(Multicast)
When it is desired to distribute a signal to a plurality of terminal devices such as an IP video system, multicast communication is used. In multicast communication, the transmitting terminal transmits a packet with the multicast group address written in the destination IP address, the receiving terminal requests the multicast group address desired to be received from the router, and the router transmits the requested multicast group address. The packet relay is started, the routing operation of the router is changed so as to transfer the corresponding packet to the requesting receiving terminal, and the internal routing information is corrected, so that the packet is sent to the receiving terminal.

  In this method, it is not necessary to change the communication setting of the transmitting terminal, but it is necessary for the receiving terminal to perform a request to stop receiving the multicast group or to stop it.

JP 2005-33511 A International Publication No. 2007/12997

  As described above, in the IP video system, since terminal devices are connected by IP packets, there is an advantage that not only video signals but also signals other than video signals such as control signals can be easily transmitted. Further, in the IP video system, it is expected that the number of cables required for signal transmission can be reduced by multiplexing and transmitting a plurality of video signals on one transmission cable.

  However, in the matrix switcher, it was possible to change the combination of the video output device and the video input device with a simple operation by simply reselecting the cross point to be connected, but switching the reception point in the IP video system In some cases, it is necessary to operate the transmitting terminal or the receiving terminal. For example, assuming a data communication system 300 based on the IP video system shown in FIG. 12, a video is transmitted from a terminal device 11-1 at a relay site serving as an outdoor transmission point via a router 40-1, and an IP network over the Internet. 50, the terminal device 11-2 at a receiving point in a certain area receives the video via the router 40-2, or the terminal device 11- at a receiving point in another area via the router 40-3. It is desirable that the reception point can be switched so that the video can be received by the receiver 3.

  In order to perform such a switching operation, according to the conventional technique, a management device (server) for managing the IP address and multicast group address of each terminal device is provided on the IP network 50 or manually. An operation to set and control an accurate value for each terminal device must be performed. That is, in the case where communication is performed between outdoor terminal devices using the Internet connection service in the IP network 50, the IP address of each terminal device may change with each connection.

  However, in general, an operation method related to setting of an IP address and an operation method of setting and controlling a remote IP address from the management device are different depending on the manufacturer and the type of the terminal device. It is difficult to automate the interconnection and switching of equipment. Such setting work is necessary not only for switching operations, but also when introducing the equipment, replacing with a replacement device due to a failure, or moving equipment to temporarily increase the equipment. The operation of the system was time-consuming and error-prone, which was an obstacle to operation.

(Batch switching)
In production of live broadcast programs, in addition to equipment that transmits the produced video signal, equipment that sends the studio video back to the site, and communication equipment that gives instructions and meetings between the broadcast site and the studio are required as terminal devices. It is. In the program relay, it is necessary to perform communication settings of equipment and communication equipment necessary for the program relay for each terminal device.

  In a data communication system that enables transmission of data such as video signals from a certain terminal device to a certain terminal device, the communication partner of each terminal device can be set without changing the communication settings of each connected terminal device. A technique that enables switching is desired.

  In view of the above-described problems, the object of the present invention is to allow predetermined data to be transmitted live between each terminal device to be interconnected, such as live video without changing the communication settings of each terminal device to be connected. In a data communication system configured to be able to easily switch communication destinations related to data transmission, a terminal device that communicates using an IP packet, and a network module relay device that interconnects each terminal device via an IP network The present invention provides a data relay device and a data communication system thereof.

  The data communication system according to the present invention defines each terminal device to be interconnected to have an IP address included in a range of public local addresses according to predetermined module basic information, and from a certain terminal device to a certain terminal Predetermined data including a video signal can be transmitted / received to / from the device, and the communication partner can be switched without changing the communication setting of each terminal device to be connected.

  For this reason, the terminal device according to the present invention has an IP address included in the range of the public local address according to the predetermined module basic information and another IP address included in the range of the public remote address according to the module basic information. Communicate with the terminal device.

  The module basic information includes a predetermined network address, a netmask, a local gateway (GW) address, a public local address, and a public remote address, and the public local address is a network segment defined by the network address and the netmask. The public remote address defines an address value not included in the network segment defined by the network address and the netmask.

  Whether or not the IP address is included in the network segment is determined by converting the IP address into a binary number, and the value of the upper bit in the range specified by the netmask matches the value converted into the network address binary number. Judgment whether or not to do.

  In addition, when a terminal device connected to a local area network (LAN) communicates with a terminal device having an IP address included in the network segment to which the terminal device belongs, direct communication is performed using the LAN. When communicating with a terminal device having an IP address of, communication is performed via a router.

  Since the terminal device sharing the module basic information has an IP address included in the public local address, it belongs to a common network segment and can be connected by one local area network (LAN). Accordingly, a set of terminal devices grouped by sharing the module basic information can be configured as a network module, and the network module can be connected to the LAN.

  Therefore, a first interface for connecting the network module via the LAN and a second interface for relaying the IP packet communicated between the network module terminal device and the communication destination terminal device to be interconnected via the IP network. And a data relay device provided with the interface.

  The data relay device according to the present invention is connected to the IP network via a router that operates as a local gateway. Instead of using the data relay device and the router, the data relay device is interconnected using a tunnel protocol. A configuration using a router that operates as a local gateway is also possible. Therefore, a data relay apparatus having an interface for connecting individual network modules in association with each other, or a router operating as a local gateway interconnected using a tunnel protocol is referred to as a “network module relay apparatus” in the present specification. Called.

  Each of the data relay devices connected in association with each of the network modules has a public local address and a mapped local address within a range in accordance with the module basic information in order to establish interconnection between the plurality of network modules. Mapping information including a local GW address, a mapped GW address, a public remote address, and a mapped remote address is stored and held.

  The mapped GW address is the IP address value that the router 40-1 connects to the first connection network 30-1. The mapped local address is selected from IP addresses included in the network segment of the first connection network 30-1.

  Each of the data relay apparatuses connected in association with each network module uses a connection control unit that can update the mapped remote address of the mapping information based on an external instruction, and the mapping information. The destination IP address of the IP packet is converted into a mapped remote address corresponding to the external instruction, the source IP address is converted into a mapped local address, or the destination IP address is set as a public local address and the source IP address is set as a public local An address conversion unit for converting each address into an address and an interface of the LAN are provided.

  Here, the address conversion unit provided in each of the data relay devices converts the target protocol address of the ARP packet into the mapped GW address and the source protocol address into the mapped local address using the mapping information, or Means is provided for converting the target protocol address into a public local address and the source protocol address into a local GW address.

  That is, the terminal device according to the present invention can transmit predetermined data live between each terminal device to be interconnected, and can switch the communication destination related to the data transmission without changing the communication setting of each terminal device. In the data communication system, a terminal device that communicates using IP packets, together with a communication destination terminal device to be interconnected, an IP address included in a range of public local addresses according to predetermined module basic information The module basic information includes a predetermined network address, a net mask, a local GW address, a public local address, and a public remote address, and the public local address is defined by the network address and the net mask. Address values included in the network segment Open remote address is characterized in that it is not included in the network segments that are defined by the network address and the netmask address value is defined.

  Further, the network module relay device according to the present invention comprises a set of terminal devices of the present invention grouped by setting the address of the module basic information in common as a network module, and connecting the network module via a LAN. And a second interface for relaying an IP packet communicating with the network module to which the communication destination terminal device to be interconnected belongs via an IP network.

  Furthermore, the data relay device according to the present invention configures a set of terminal devices of the present invention grouped by setting addresses in common with the module basic information, and connects the network modules via a LAN. A mapping information storage unit that stores and holds mapping information including a first interface, a public local address, a mapped local address, a public remote address, and a mapped remote address; and the mapping information can be updated based on an external instruction. A connection control unit that converts the destination IP address of the IP packet from the public remote address to the mapped remote address, and the source IP address from the public local address to the mapped local address using the mapping information, Or an address conversion unit that converts a destination IP address from a mapped local address to a public local address, and a source IP address from a mapped remote address to a public remote address, and the communication destination terminal device to which the interconnection target belongs. And a second interface for relaying an IP packet communicating with the network module via the IP network.

  In the data relay apparatus according to the present invention, the address conversion unit further stores and holds a local GW address and mapped GW address information as the mapping information, and uses the mapping information to set a target protocol address of the ARP packet as a local GW. Convert address to mapped GW address, source protocol address from public local address to mapped local address, or target protocol address from mapped local address to public local address, source protocol address to mapped GW Means is provided for converting each address into a local GW address.

  Furthermore, the data communication system according to the first aspect of the present invention includes the data relay device of the present invention, a network module connected using the data relay device, and each of the data relay devices connected to the IP network. The terminal device belonging to the first network module and the terminal device belonging to the second network module establish a connection by address conversion to enable predetermined transmission of live data. It is characterized in that the communication destination related to the data transmission can be switched without requiring any change.

  Furthermore, the data communication system according to the second aspect of the present invention includes a network module relay device of the present invention, a network module connected using the network module relay device, and each network module relay connected to an IP network. The apparatus establishes a connection using a tunnel protocol between the terminal apparatus belonging to the first network module and the terminal apparatus belonging to the second network module, and allows predetermined data to be transmitted live. It is possible to switch the communication destination related to the data transmission without changing the communication setting.

  According to the present invention, when the manufacturer and the type of the terminal device such as the video encoder and decoder are different and the operation method regarding the setting of the IP address is different, or the operation for setting and controlling the remote IP address from the predetermined management device Even if the method is different, once the setting according to the module basic information is performed, it is possible to automate the switching of the communication partner without changing the communication setting of each terminal device to be connected.

  In addition, according to the present invention, the module basic information related to the setting of the IP address of the terminal device to be connected is shared, so that the equipment constituting each terminal device can be introduced or replaced with a replacement device due to a failure. Such setting work can be made common even when equipment is moved to temporarily increase equipment, or the setting work itself can be made unnecessary.

  In particular, according to the present invention, since it is not necessary to set connection or switching for each individual terminal device as in the conventional technique, a group of transmission-side communication devices that transmit video signals from a relay site, live By setting a network module according to the purpose of communication and the installation location, such as a group of communication equipment on the broadcast station side that receives relay video, you can connect communication equipment for relay sites used for program relay in a batch, It becomes easy to switch the connection.

It is a block diagram which shows schematic structure of the data communication system of 1st Embodiment by this invention. (A) and (b) are basic module information of a certain network module (live field module) to be interconnected and another network module (live receiving module) in the data communication system according to the first embodiment of the present invention. It is a figure which illustrates each structure of basic module information. It is a block diagram which shows schematic structure of the data relay apparatus connected via a LAN with a certain terminal device in the 1st network module in the data communication system of 1st Embodiment by this invention. (A), (b) are the mapping information of the first network module held by a certain data relay device in the data communication system of the first embodiment according to the present invention, and the second held by the data relay device of the connection partner. It is a figure which illustrates each allocation of the mapping information of a network module. It is a figure which illustrates matching with the public local address and mapped local address in the data communication system of 1st Embodiment by this invention. It is a flowchart which shows operation | movement of the address conversion part in the data relay apparatus which processes the packet received from the 1st network module side in the data communication system of 1st Embodiment by this invention. It is a figure which shows the packet format (Ethernet (trademark) frame (except a preamble and FCS)) of the ARP packet for resolving an IPv4 address which can be utilized in the data communication system of 1st Embodiment by this invention. . It is a flowchart which shows operation | movement of the address conversion part in the data relay apparatus which processes the packet received from the router side in the data communication system of 1st Embodiment by this invention. It is a block diagram which shows schematic structure of the data communication system of 2nd Embodiment by this invention. It is a block diagram which shows schematic structure of the conventional matrix switcher. It is a block diagram which shows schematic structure of the data communication system of a prior art. It is a block diagram which shows schematic structure of the data communication system assumed from the prior art.

  Hereinafter, data communication systems according to embodiments of the present invention will be described with reference to the drawings.

[Data Communication System of First Embodiment]
(Device configuration)
FIG. 1 is a block diagram showing a schematic configuration of a data communication system 1 according to the first embodiment of the present invention.

  In the data communication system 1 of the first embodiment shown in FIG. 1, terminal devices 11-1, 11-2, and 11-3 such as video transmission devices such as transmission terminals and reception terminals, communication devices, and file transmission devices are directly connected. Instead of connecting to a router, terminal devices that are to be connected together are connected to a common LAN and then connected to the router via a data relay device.

  For example, the terminal device 11-1 and a terminal device that is not shown but are to be connected together with the terminal device 11-1 are connected to the common LAN 12-1 and connected to the data relay device 20-1. . Further, the data relay apparatus 20-1 is connected to the router 40-1 operating as a local gateway by the first connection network 30-1, and is connected to the IP network 50 through the router 40-1.

  Similarly, the terminal device 11-2 and the terminal device to be connected together with the terminal device 11-1 are connected to a common LAN 12-2 and connected to the data relay device 20-2. Further, the data relay device 20-2 is connected to the IP network 50 via the router 40-2 operating as a local gateway by the second connection network 30-2.

  Similarly, the terminal device 11-3 and the terminal device to be connected together with the terminal device 11-3 are connected to a common LAN 12-3 and connected to the data relay device 20-3. Furthermore, the data relay device 20-3 is connected to the IP network 50 via the router 40-2 operating as a local gateway by the third connection network 30-3.

  The LAN 12-1, the LAN 12-2, the LAN 12-3, the first connection network 30-1, the second connection network 30-2, and the third connection network 30-3 are, for example, Ethernet (registered trademark) or 802.11a / b / g. It can be constructed using a wireless LAN such as / n.

  In the present specification, the terminal devices connected to one common LAN are collectively referred to as “network modules”, and FIG. 1 shows an example in which three network modules are configured. The plurality of terminal devices 11-1 belong to the first network module 10-1, and one or more terminal devices 11-2 belong to the second network module 10-2, and one or more terminal devices 11-. 3 belongs to the third network module 10-3.

  Each data relay device 20-1, 20-2, 20-3 has the same structure. For example, as will be described in detail later, the data relay device 20-1 receives an IP packet sent from the terminal device 11-1 of the first network module 10-1 toward the public remote address, and is written in the IP packet. By rewriting the source IP address from the public local address of the first network module 10-1 to the mapped local address and rewriting the destination IP address from the public remote address of the first network module 10-1 to the mapped remote address, The packet is transferred to the data relay apparatus 20-1.

  Further, the data relay device 20-2 receives the IP packet transferred from the data relay device 20-1, and the source IP address written in the IP packet is determined from the mapped remote address of the second network module 10-2. By rewriting to the public remote address and rewriting the destination IP address from the mapped local address to the public local address, the transferred IP packet is transferred to the terminal device 11-2 of the second network module 10-2.

  As described above, the data relay device 20-1 and the data relay device 20-2 rewrite the transmission source IP address and the destination IP address written in the IP packet, and thereby the terminal device 11- of the first network module 10-1. 1 and the terminal device 11-2 of the second network module 10-2 can communicate with each other.

(Module basic information)
The module basic information is information that defines the characteristics of the source IP address and the destination IP address of the IP packet used by the terminal device for communication. Although details will be described later, it includes a public local address and a public remote address. The public local address and the public remote address are a set of IP addresses.

  The public local address is composed of an IP address belonging to one network segment, and the public remote address is composed of an IP address not belonging to this network segment.

  The communication defined in the module basic information is an IP packet in which a terminal device having an IP address included in a public local address transmits a public remote address as a destination IP address, and a public local using the public remote address as a source IP address. This is communication performed using an IP packet whose destination IP address is a terminal device having an address.

(Network module)
The network module is a set of terminal devices that perform IP communication in accordance with predetermined module basic information.

  A terminal that performs communication according to the module basic information has an IP address included in the public local address of the module basic information, and performs communication with any IP address included in the public remote address of the module basic information as a destination or a transmission source. .

  For this reason, in the IP packet transmitted by the terminal included in the network module, the destination IP address is included in the public remote address, and the transmission source IP address is included in the public local address. Conversely, in an IP packet transmitted to a terminal included in the network module, the destination IP address is included in the public local address, and the transmission source IP address is included in the public remote address.

  Since the public local address of the module basic information is composed of IP addresses belonging to one network segment, the terminals included in the network module are connected to one common LAN.

  Hereinafter, a set of terminal devices that perform IP communication according to specific module basic information is referred to as a network module according to the module basic information.

  The first network module 10-1, the second network module 10-2, and the third network module 10-3 follow the first, second, and third module basic information, respectively.

(Mapping information)
The mapping information is information used to convert the IP packet transmitted from the network module and the IP address of the IP packet transmitted to the network module. The data relay device holds mapping information for each network module to which the data relay device is connected.

Although details will be described later, the mapping information includes a public local address, a mapped local address, a public remote address, and a mapped remote address. The mapped local address has a one-to-one correspondence with the public local address, and the mapped remote address has a one-to-one correspondence with the public remote address.
When an alternative method for rewriting ARP packets described later is not used, the local GW address and the mapped GW address are always included as mapping information in order to rewrite the ARP packet.

(Data relay device)
The data relay apparatus 20-1 connected to the first network module via the LAN 12-1 and the router 40-1 via the first connection network 30-1 transmits the source IP address of the received IP packet according to the mapping information. And the destination IP address is converted.

  Since the terminal included in the first network module performs communication according to the first module basic information, the source IP address of the IP packet received from the LAN 12-1 is a public local address, and the destination IP address is a public remote address. is there. For this reason, this is converted into a mapped local address and a mapped remote address.

  Further, since the destination IP address of the IP packet that can be received by the terminal included in the first network module is the public local address, and the source IP address is the public remote address, the first connection network 30-1 The destination IP address of the received IP packet is converted from the mapped local address to the public local address, and the source IP address is converted from the mapped remote address to the public remote address.

  The same applies to the data relay apparatuses 20-2 and 20-3.

(Method of interconnection)
In the data communication system 1 according to the first embodiment, the IP network 50, the router 40-1, the router 40-2, and the router 40-3 are configured to send packets addressed to the mapped local address of the first network module to the router 40-1. A packet addressed to the mapped local address of the second network module is transferred to the router 40-2, and a packet addressed to the mapped local address of the third network module is transferred to the router 40-3.

  When interconnecting the first network module and the second network module, the mapped remote address in the mapping information of the first network module is changed to the mapped local address of the second network module, and the mapped information in the mapping information of the second network module is used. Set the remote address to the mapped local address of the first network module.

  As a result, the destination IP address of the IP packet transmitted by the terminal device of the first network module is converted to the mapped local address of the second network module by the data relay device 20-1, and the IP network 50, the router 40-1, and the router 40-2 is sent to the data relay device 20-2. The destination IP address of this IP packet is converted into the public local address of the second network module by the data relay device 20-2 and sent to the terminal device of the second network module.

  Conversely, the destination IP address of the IP packet transmitted by the terminal device of the second network module is converted to the mapped local address of the first network module by the data relay device 20-2, and the IP network 50, router 40-2, router 40-1 is sent to the data relay device 20-1. The destination IP address of this IP packet is converted to the public local address of the first network module by the data relay device 20-1, and sent to the terminal device of the first network module.

(Switch connection destination)
When switching the connection destination of the first network module from the second network module to the third network module, the mapped remote address in the mapping information of the first network module is changed to the mapped local address of the third network module, and the third network The mapped remote address in the module mapping information is set to the mapped local address of the first network module.

  As a result, the IP packet transmitted from the terminal device of the first network module is sent to the terminal device of the second network module. Conversely, the IP packet transmitted from the terminal device of the third network module is sent to the terminal device of the first network module. Can be switched to be sent to.

  In this way, in each data relay device 20-1, 20-2, 20-3, each terminal device 11-1, 11-2 to be connected is converted by the IP address conversion process of the IP packet based on each network module mapping information. Interconnection is possible without changing any communication settings to communicate with the public remote address. Further, the terminal device 11-1 can switch the communication partner from the terminal device 11-2 to the terminal device 11-3 without changing any communication setting.

  Hereinafter, the first to third network modules 10-1, 10-2, and 10-3 will be described as the network module 10 without any distinction. Similarly, when the terminal devices 11-1, 11-2, and 11-3 belonging to the first to third network modules 10-1, 10-2, and 10-3 are described without distinction, the terminal devices 11 are described. . Similarly, when the data relay devices 20-1, 20-2, and 20-3 are described without distinction, the data relay device 20 is used. Similarly, the routers 40-1, 40-2, and 40-3 that operate as local gateways are also described as the router 40 when they are described without distinction.

(Details of basic module information)
The terminal device 11 of each network module 10 performs IP communication defined by the module basic information. 2A and 2B, in the data communication system 1 of the first embodiment, basic module information of a certain network module (live site module) to be interconnected and another network module (live Each configuration of the basic module information of the receiving module) is illustrated.

  The module type is identification information of module basic information.

  The connection module type is a set of module types, and includes the module type of the module basic information that is followed by the network module that can be connected to the network module according to the module basic information.

  The public local address is a network address, a subset of IP addresses constituting a network segment defined by a netmask, or a range of IP addresses. For example, if the network segment is specified by the network address 192.168.20.0 and the netmask 255.255.255.0, it is composed of a subset of IP addresses from 192.168.20.0 to 192.168.20.255, for example 192.168.20.2 to 192.168.20.5 The range.

  The public remote address is a set of IP addresses or a range of IP addresses of the counterpart terminal device that is a communication partner of the network module terminal device according to the module basic information, and the module basic information that the network module to which the counterpart terminal device belongs follows. A set of IP addresses or a range of IP addresses included in the public local address.

  Communication between the terminal devices 11 between the network modules 10 is performed for a terminal device having an IP address included in the public local address (for example, the terminal device 11-1) and a terminal device having an IP address included in the public remote address (for example, This is performed with the terminal device 11-2).

  The module basic information according to the present invention has information on a network address, a netmask, and a local GW address necessary for the terminal device 11 to connect to the IP network, and further includes a module type, a public local address, and a public remote address.

  The public remote address is an IP address that is not included in the network segment defined by the network address and netmask of the module basic information. For example, if the network segment is specified by the network address 192.168.20.0 and the netmask 255.255.255.0, it is composed of a subset of IP addresses other than the IP addresses from 192.168.20.0 to 192.168.20.255, for example, 192.168.30.2 To 192.168.30.5.

  The network setting of the terminal device of the network module sets the IP address of the terminal device as one of the IP addresses included in the public local address of the module basic information, and sets the net mask of the module basic information and the local GW address of the module basic information. Set as netmask and default gateway address.

  In the example of the module basic information at the live site in FIG. 2A, the network segment defined by the network address and the netmask includes IP addresses from 192.168.20.0 to 192.168.20.255. Since the public remote address is in the range from 192.168.30.2 to 192.168.30.5, it is not included in this network segment. Therefore, in the example of the module basic information in the live reception of FIG. 2B, it is associated with the module basic information shown in FIG.

(Aggregation of IP packets addressed to public remote addresses)
With this feature, for example, the destination IP address of an IP packet transmitted by one or more terminal devices 11-1 belonging to the network module 10-1 is a public remote address. In IP communication, it is determined using the IP address and netmask of the terminal device whether the destination IP address of the IP packet is included in the network segment. As a result of the determination, if it is determined that the destination IP address of the IP packet is not included in the network segment, the IP packet is transferred to the default gateway, that is, the local GW.

  Since the public remote address is not included in the network segment, all IP packets transmitted from the terminal device of the network module 10-1 are sent to the local GW.

  With this feature, IP packets sent to the public remote address from one or a plurality of terminal devices 11-1 of the network module can be aggregated in the local GW.

  In the data communication system 1 of the first embodiment, the network module is connected to the router 40-1 via the data relay device 20-1. As will be described later, the data relay apparatus 20-1 converts the local GW address and the mapped GW address. By matching the mapped GW address with the IP address of the router, IP packets sent to the public remote address can be collected in the data relay device 20-1.

  More specifically, in IP communication using Ethernet (registered trademark) or wireless LAN, an ARP (Address Resolution Protocol) is used to send an IP packet to a device having a default gateway IP address (local GW in the present embodiment). ) Is used to check the MAC address of the device having the local GW address. The data relay apparatus 20-1 uses the method described later, the terminal uses the mapped GW address, that is, the IP address of the local GW written in the target protocol address of the ARP packet for checking the MAC address of the apparatus having the address of the local GW. The IP address of the router is converted, and the protocol address of the transmission source of the ARP packet sent from the router as a response is rewritten from the IP address of the router to the local GW address. Thereby, the terminal device 10-1 records the MAC address of the router 40-1 as the MAC address of the local GW, and sends an IP packet to be sent to the local GW to the MAC address of the router 40-1. Since the network module is connected to the router 40-1 via the data relay device 20-1, IP packets sent to the public remote address can be collected in the data relay device 20-1.

  Therefore, the communication between the network modules 10 can be aggregated into the communication between the local GWs. In the data communication system 1 of the first embodiment, the communication is aggregated into the communication between the corresponding data relay apparatuses 20, and each data relay is performed. The device 20 can control all communication between the network modules 10 by extracting an IP packet responsible for communication between the public local address and the public remote address.

  The basic module information is determined according to the communication purpose, installation location, and the like, such as a group of communication devices on the site side that transmits live relay video and a group of communication devices on the broadcast station side that receives live relay video. As a result, it becomes easy to collectively connect or switch the relay site communication devices used for program relay.

(Switching connections between network modules)
Thus, the terminal device 11 of the network module 10 has a preset public local address, and communicates with another terminal device 11 having a preset public remote address. By the way, when the network module 10 is directly connected to the IP network 50 via the router 40 that simply operates as a local gateway, for example, the terminal device 11-1 and the terminal device 11-2 of the communication partner set the IP network 50 and the public local address. The communication partner cannot be switched to another terminal device (for example, the terminal device 11-3).

  For this reason, in the data communication system 1 shown in FIG. 1, the data relay device 20 is provided between the network module 10 and the router 40 so that the connection between the network modules 10 can be switched. Details of the data relay device 20 will be described below.

(Data relay device)
FIG. 3 shows a data relay device 20-1 connected via a LAN 12-2 to a certain terminal device 11-1 in the first network module 10-1 in the data communication system 1 according to the first embodiment of the invention. It is a block diagram which shows schematic structure.

  The data relay device 20 (representatively, the data relay device 20-1 in FIG. 3) includes a LAN interface 21, an address conversion unit 22, a LAN interface 23, a mapping information storage unit 24, and a connection control unit 25.

  The LAN interface 21 has a function of transmitting and receiving an Ethernet (registered trademark) frame, and communicates with the terminal device 11-1 of the first network module 10-1 and the Ethernet (registered trademark) via the layer 2 switch in the LAN 12-1. ) Send and receive frames.

  The LAN interface 23 has a function of transmitting and receiving an Ethernet (registered trademark) frame. The LAN interface 23 is connected directly to the router 40-1 via the layer 2 switch in the first connection network 30-1 (not shown). Send and receive (registered trademark) frame.

(Sharing of LAN interfaces 21 and 23 using tag VLAN)
The data relay device 20 is connected to the connection with the LAN 12-1 via the layer 2 switch in the LAN 12-1 and the LAN interface 21, and is connected to the first connection network 30-1 with the first connection network 30. -The layer 2 switch in -1 is connected through the LAN interface 23.

  Here, if a layer 2 switch corresponding to the tag VLAN (IEEE 802.1Q) is used, the layer 2 switch used for connection to the LAN 12-1 and the layer 2 switch used for connection to the first connection network 30-1 are: The LAN interface 21 and the LAN interface 23 can be combined into a single tag VLAN-compatible LAN interface (not shown).

  The tag VLAN-compatible LAN interface uses an Ethernet (registered trademark) frame to which 32-bit information called a tag is added, so that it is an Ethernet (registered trademark) frame of the LAN 12-1 or the first connection network 30-1. Identify whether it is an Ethernet (registered trademark) frame.

  The tag VLAN-compatible LAN interface determines whether the received Ethernet (registered trademark) frame tag value is the Ethernet (registered trademark) frame received from the LAN 12-1 or received from the first connection network 30-1. And the Ethernet frame received by the LAN interface 21 and the Ethernet frame received by the LAN interface 23 according to the determination result.

  Conversely, a tag of LAN 12-1 is used for the Ethernet® frame transmitted by the LAN interface 21, and a tag of the first connection network 30-1 is used for the Ethernet® frame transmitted by the LAN interface 23. Send.

  Therefore, the LAN interface 21 and the LAN interface 23 can be substituted by using a tag VLAN compatible LAN interface.

  The address conversion unit 22 inspects the Ethernet (registered trademark) frame received by the LAN interface 21, rewrites a part of the IP address stored in the Ethernet (registered trademark) frame, and outputs the IP address to the LAN interface 23; The Ethernet interface (registered trademark) frame received by the LAN interface 23 is inspected, and a part of the IP address stored in the Ethernet (registered trademark) frame is rewritten and output to the LAN interface 21.

  The address conversion unit 22 rewrites the IP address and recalculates the checksum values of the IP header, UDP header, and TCP header included in the IP packet.

  FIG. 3 shows an example in which the data relay device 20-1 has only one LAN interface 21 connected to the first network module 10-1. However, the LAN interface 21 is added, and mapping information described later is added. It is good also as a structure which connects several 1st network module 10-1 by adding correspondingly. In a configuration in which a plurality of first network modules 10-1 are connected, each network module is connected to the data relay device 20-1 via the added interface 21.

The mapping information storage unit 24 is a functional unit that stores and holds mapping information used by the address conversion unit 22 to convert the IP address stored in the Ethernet (registered trademark) frame. A remote address, a mapped local address, and a mapped remote address are created for each network module 10-1 to which the data relay apparatus 20-1 is directly connected.
When the data relay apparatus 20-1 rewrites the ARP packet, the mapping information storage unit 24 further includes a local GW address and a mapped GW address as mapping information.

  The connection control unit 25 receives an external instruction (connection destination instruction) for specifying the connection destination of the first network module 10-1 and updates the mapping information stored and held in the mapping information storage unit 24. For example, mapping information is created in advance for each connection destination, and when a new connection destination is designated by a connection destination instruction, the mapping information is updated to mapping information corresponding to the designated connection destination. As another method, mapping information excluding the mapped remote address is created in advance prior to the connection, and when the connection destination instruction is obtained, the mapped remote address of the first network module 10-1 and the connection partner are obtained. A mapped remote address is created from the public local address and the mapped local address of the network module 10.

  The mapped remote address is created so as to have a one-to-one correspondence with the mapped remote address of the first network module 10-1. For example, when the range of the mapped remote address matches the range of the public local address of the network module 10 of the connection partner, the mapped local address of the network module 10 of the connection partner is used as it is as the mapped remote address.

  When the mapped remote address is smaller than the range of the public local address of the network module 10 of the connection partner, a terminal device that cannot communicate may occur.

  Also, when the first network module 10-1 connected to the LAN interface 21 is disconnected and a network module 10 having a different module type is connected, or the network setting used for connection with the router 40-1 by relocation or the like is set. A function for updating the mapping information when changing may be added.

  For example, as an external instruction (connection destination instruction) to the connection control unit 25, mapping information is created in advance for each module type and network setting for connection with the router 40-1, and the mapping information is set according to the module type to be connected and the network setting. Can be switched.

  In this way, the data relay device 20-1 rewrites the transmission source IP address and the destination IP address so that the second network module 10-2 connects the IP packet transmitted from the first network module 10-1. It is possible to transfer to the data relay device 20-2 and to switch the transfer destination to the data relay device 20-3 to which the third network module 10-3 is connected.

  In the IP network 50, various layer 2 transmission means such as Ethernet (registered trademark), wireless LAN, and LTE can be used. However, for the sake of simplicity, in the above description, the first to third connection networks 30-1 are used. , 30-2 and 30-3 are performed using Ethernet (registered trademark).

  4 (a) and 4 (b) show the first network module 10-1 held by a certain data relay device (for example, the data relay device 20-1) in the data communication system 1 of the first embodiment according to the present invention. It is a figure which illustrates each allocation of mapping information and the mapping information of the 2nd network module 10-2 which the data relay apparatus 20-2 of a connection other party hold | maintains, for example.

  For example, referring to FIG. 4A, for the public local address, local GW address, and public remote address, the values of the module basic information (see FIG. 2A) of the first network module 10-1 are used as they are. For the module type and connection module type information, the values of the module basic information (see FIG. 2A) are used as they are, but these pieces of information are not essential. The connection state holds the connection state with the network module of the connection partner, and holds states such as being connected and disconnected.

  The mapped GW address specifies the IP address of the router 40-1.

  The mapped local address is a set of IP addresses that can communicate with each other via the router 40-1 and the IP network 50, and includes the same number of IP addresses as the IP addresses included in the public local address. In the mapping information according to the present invention, the public local address and the mapped local address are associated one-to-one.

  For example, IP addresses can be associated with integers, public local addresses and mapped local addresses can be arranged in ascending order, and addresses having the same order from the top can be associated.

  More specifically, the router 40-1 is set to connect the subnet in the range of 10.0.1.0 to 10.0.1.255 with the IP network 50, and the data relay apparatus 20-1 as a router having the IP address 10.0.1.1. In this case, the mapped GW address is 10.0.1.1, and the mapped public address is selected from 253 IP addresses from 10.0.1.2 to 10.0.1.254. In the example of FIG. 4A, four public local addresses from 192.168.20.2 to 192.168.20.5 and four mapped public addresses from 10.0.1.6 to 10.0.1.9 are arranged in ascending order and associated with each other.

  FIG. 5 shows public local addresses and mapped local addresses of the first network module 10-1, the second network module 10-2, and the third network module 10-3 in the data communication system 1 according to the first embodiment of the present invention. FIG.

  The mapped remote address includes the same number of IP addresses as the public local address, and holds all or a part of the public local address of the network module of the connection partner.

  In the example of the data communication system 1 of the first embodiment shown in FIG. 1, when the first network module 10-1 and the second network module 10-2 are connected, the data relay device 20-2 is the second network module. The same value as the mapped local address of the mapping information held in association with 10-2 is held.

  In the example shown in FIG. 5, the public remote address of the first network module 10-1 is composed of four IP addresses. Since the public local addresses of the second network module 10-2 connected to the first network module 10-1 also have four IP addresses from 192.168.30.2 to 192.168.30.5, these addresses are made to correspond one-to-one. It is possible. Therefore, the mapped public address 10.0.2.2 to 10.0.2.5 corresponding to the public local address of the network module 3-2 is set as the mapped remote address of the first network module 10-1, thereby having a one-to-one correspondence with the public remote address. The mapped remote address to be associated is obtained.

  If the range of the public local address of the second network module 10-2 to be connected is wider than the range of the public remote address of the first network module 10-1, the public remote address of the first network module 10-1 is set. The mapped local address of the second network module 10-2 of the connection partner corresponding to the public local address of the second network module 10-2 of the connection partner is extracted, and the map of the first network module 10-1 is extracted. Remote address.

(Operation of address converter)
<Address conversion from connected network module>
With reference to FIG. 6, the processing of the Ethernet® frame received from the LAN interface 21 by the address conversion unit 22 in the data relay device 20 will be described in detail.

  First, the address conversion unit 22 determines whether an Ethernet (registered trademark) frame received from the LAN interface 21 includes an ARP (Address Resolution Protocol) packet or an IP packet (step S1), and includes an ARP packet. In step S2, if an IP packet is included, the process proceeds to step S3.

  The type of packet can be identified by the value of the 16-bit protocol type in the header part of the Ethernet (registered trademark) frame. The value of the protocol type of the ARP packet is 0x0806, and the protocol type of the IP packet (version 4) is 0x0800. When tag VLAN (IEEE802.1Q) is used, one or a plurality of 32-bit tags are inserted before the protocol type. Since the value of the first 16 bits of the tag is 0x8100, which is different from the protocol type value of the ARP packet or IP packet, this is detected when a tag is inserted, and the 16-bit value immediately after the tag is read. Thus, the type of packet can be determined.

  FIG. 7 shows an example of the Ethernet (registered trademark) frame structure of the ARP packet when the IPv4 address is resolved by Ethernet (registered trademark). Details of the ARP protocol are disclosed in RFC826.

  Referring to FIG. 6, subsequently, the address translation unit 22 checks whether or not the value of the target protocol address of the ARP packet matches the local GW address of the mapping information (step S2). Proceed to S4. In other cases, for example, the Ethernet (registered trademark) frame is discarded (step S9).

  Subsequently, the address conversion unit 22 changes the target protocol address to the mapped GW address, and when the transmission source protocol address is included in the public local address, the transmission source protocol address corresponds to the public local address. The address is changed to a mapped local address (step S4), and the process proceeds to step S10.

  Subsequently, the address conversion unit 22 transmits an Ethernet (registered trademark) frame from the LAN interface 23 (step S10).

  On the other hand, when the address conversion unit 22 determines that the Ethernet (registered trademark) frame received from the LAN interface 21 includes an IP packet (step S1), the IP header of the IP packet stored in the Ethernet (registered trademark) frame Whether the destination IP address is a local GW address or an address included in the public remote address. If the destination IP address is a local GW address, the process proceeds to step S7. If it is included in the public remote address, the process proceeds to step S6. If this is not the case, the Ethernet (registered trademark) frame may be discarded, but the process proceeds to step S8 without discarding in this example (step S5). When the mapping information storage unit 24 does not include the local GW address and the mapped GW address as the mapping information, the destination IP address of the IP header of the IP packet stored in the Ethernet (registered trademark) frame is the local GW address. Whether or not there is an inspection is not performed, and the process of step S7 is not performed.

  If the address is included in the public remote address in the inspection in step S5, the address conversion unit 22 regards the destination IP address as the public remote address and changes it to the corresponding mapped remote address (step S6).

  If the address is included in the local GW address in the inspection in step S5, the address conversion unit 22 changes the destination IP address to the mapped GW address (step S7).

  Preferably, in order to stop transmission of the packet when it is not in the connection state, the address translation unit 22 monitors the connection state based on the mapping information (see FIG. 4A) in step S5, and the mapping information If the connection state is disconnected, the process proceeds to step S9, the Ethernet (registered trademark) frame is discarded (not shown), and if connected, a function to proceed to step S8 may be added.

  Subsequently, the address conversion unit 22 regards the source IP address as a public local address, changes it to the corresponding mapped local address, recalculates the checksum of the IP header, and then proceeds to step S10 (step S8). In step S8, if the IP packet includes a TCP header, the TCP header checksum is recalculated. If the IP packet includes a UDP header and the UDP header checksum is other than 0, the UDP header checksum is recalculated.

  The address conversion unit 22 transmits an Ethernet (registered trademark) frame from the LAN interface 23 (step S10).

  Thus, the address conversion unit 22 determines whether the Ethernet (registered trademark) frame received from the LAN interface 21 includes an ARP packet or an IP packet, and determines whether the packet is an ARP packet or an IP packet. Based on the type, the protocol address or destination IP address of the target is analyzed, and if it is an Ethernet (registered trademark) frame sent to the local GW, it is converted into a mapped GW address to convert it into the router 40-1. Address translation to deliver to When the destination IP address is an Ethernet (registered trademark) frame sent to the public remote address, the data relay device 20-2 (or 20-3) is converted by converting the frame into a mapped remote address. The address conversion is performed so as to reach the terminal device 11-2 (or 11-3) in the network module 10-2 (or 10-3) of the communication partner via the communication.

<Address translation of packets from connected routers>
Next, processing of the Ethernet® frame received from the LAN interface 23 by the address conversion unit 22 in the data relay device 20 will be described in detail with reference to FIG.

  First, the address translation unit 22 determines whether the Ethernet (registered trademark) frame received from the LAN interface 23 includes an ARP packet or an IP packet (step S21). If the ARP packet is included, the address conversion unit 22 proceeds to step S22. If the IP packet is included, the process proceeds to step S23.

  Subsequently, the address conversion unit 22 checks whether the value of the protocol address of the transmission source of the ARP packet matches the mapped GW address of the mapping information, and the target protocol address is a mapped local address (step S22). If they match, the process proceeds to step S24; otherwise, the Ethernet (registered trademark) frame is discarded (step S29).

  Subsequently, the address conversion unit 22 changes the target protocol address to the public local address corresponding to the mapped local address, changes the source protocol address to the local GW address (step S24), and proceeds to step S30.

  Subsequently, the address conversion unit 22 transmits an Ethernet (registered trademark) frame from the LAN interface 21 (step S30).

  On the other hand, when the address conversion unit 22 determines that the Ethernet® frame received from the LAN interface 23 includes an IP packet (step S21), the source IP address of the IP header is the mapped GW address or the mapped Whether the address is included in the remote address is checked. If it is a mapped GW address, the process proceeds to step S27. If it is included in the mapped remote address, the process proceeds to step S26. Although the registered trademark frame may be discarded, the process proceeds to step S28 without discarding in this example (step S25). When the mapping information storage unit 24 does not include the local GW address and the mapped GW address as the mapping information, the destination IP address of the IP header of the IP packet stored in the Ethernet (registered trademark) frame is the mapped GW address. Whether or not there is an inspection is not performed, and the process of step S27 is not performed.

  When the transmission source IP address is an address included in the mapped remote address in the inspection in step S25, the address conversion unit 22 regards the transmission source IP address as the mapped remote address and changes it to the corresponding public remote address ( Step S26).

  When the transmission source IP address is a mapped GW address in the inspection in step S25, the address conversion unit 22 changes the transmission source IP address to the local GW address (step S27).

  Preferably, in order to stop the transmission of the packet when it is not in the connection state, the address translation unit 22 monitors the connection state based on the mapping information in the inspection of step S25 (see FIG. 4A). If the connection state of the mapping information is disconnected, the process may proceed to step S9 to discard the Ethernet (registered trademark) frame (not shown), and if connected, a function to proceed to step S28 may be added.

  Subsequently, the address conversion unit 22 regards the destination IP address as a mapped local address, changes it to the corresponding public local address, recalculates the checksum of the IP header, and then proceeds to step S30 (step S28). In step S28, if the IP packet includes a TCP header, the checksum of the TCP header is recalculated. If the IP packet includes the UDP header and the checksum of the UDP header is other than 0, the checksum of the UDP header is recalculated.

  The address conversion unit 22 transmits an Ethernet (registered trademark) frame from the LAN interface 21 (step S30).

  Thus, the address conversion unit 22 determines whether the Ethernet (registered trademark) frame received from the LAN interface 23 includes an ARP packet or an IP packet, and determines whether the packet is an ARP packet or an IP packet. Based on the type, the target protocol address or destination IP address is converted from the mapped local address to the public local address of the terminal device 11-1 in the first network module 10-1.

(Alternative method for rewriting ARP packet)
The relay device 20-1 receives the IP packet sent from the terminal device 11-1 to the router 40-1 via the LAN interface 21 and the IP packet sent from the router 40-1 to the terminal device 11-1 via the LAN interface 23. In order to do this, a process of rewriting the target protocol address and the source protocol address of the ARP packet is performed.

  For this reason, in steps S4, S10, S24, and S30 described above, the protocol address of the ARP packet is rewritten and data relay processing is performed for transmission from an interface different from the received interface. However, instead of relaying the ARP request packet, In addition, this function can be replaced by transmitting an ARP response packet responding to the terminal device 11-1 or the router 40-1 from which the relay device 20-1 has made an ARP request.

  For example, when the OPCODE of the ARP packet is 0x0001 (REQUEST) instead of the process of step S4 described above, this Ethernet (registered trademark) frame is discarded and the terminal device 11-1 that transmitted the ARP packet is preliminarily set. The recorded ARP response packet for notifying the MAC address of the router 40-1 may be transmitted from the LAN interface 21 (step S4 ′).

  Similarly, if the OPCODE of the ARP packet is 0x0001 (REQUEST) instead of the process of step S24 described above, this Ethernet (registered trademark) frame is discarded and the router 40-1 that transmitted the ARP packet is preliminarily set. The ARP response packet notifying the MAC address of the terminal device 11-1 corresponding to the recorded mapped local address may be transmitted from the LAN interface 23 (step S24 ').

  As another alternative method, the MAC address M201 of the relay device 20-1 is prepared, and in step S4 ′ or step S24 ′, the MAC address of the router 40-1 or the MAC address of the terminal device 11-1 An ARP response packet notifying the MAC address M201 is transmitted, and in step S3 described above, it is checked whether the destination MAC address matches M201 (step S3 ′). When this alternative method is used, the transmission MAC address of the Ethernet (registered trademark) frame transmitted in steps S10 and S30 is changed to the MAC address M201, and the Ethernet (registered trademark) frame is converted in step S30. Is transmitted, the destination MAC address corresponding to the destination IP address of the IP packet is retrieved, and the destination MAC address is rewritten to the retrieved value (steps S10 ′ and S30 ′).

[Data Communication System of Second Embodiment]
(Device configuration)
FIG. 8 is a block diagram showing a schematic configuration of the data communication system 2 according to the second embodiment of the present invention.

  In the data communication system 2 of the second embodiment shown in FIG. 9, as in the first embodiment, terminal devices 11-1a, 11- such as video transmission devices such as transmission terminals and reception terminals, communication devices, and file transmission devices. 1b etc. are connected together to the LAN 12-1 as the first network module 10-1, and similarly the terminal devices 11-2a, 11-2b etc. are connected together to the LAN 12-2 as the second network module 10-2. doing.

  Further, the terminal device 11 of each network module 10 performs IP communication defined by the module basic information as exemplified in FIGS. 2A and 2B, as in the first embodiment.

(Switching connections between network modules)
As described above, the terminal device 11 of each network module 10 has a preset public local address, and communicates with another terminal device 11 having a preset public remote address. By the way, when the network module 10 is directly connected to the IP network 50 via the router 40 that simply operates as a local gateway, for example, the terminal device 11-1 and the terminal device 11-2 of the communication partner set the IP network 50 and the public local address. The communication partner cannot be switched to another terminal device (for example, the terminal device 11-3).

  For this reason, in the data communication system 1 according to the first embodiment, the example in which the data relay device 20 is provided between the network module 10 and the router 40 and the connection between the network modules 10 can be switched has been described. In the data communication system 2 of the second embodiment, as shown in FIG. 9, a tunnel protocol such as GRE (RFC2784 Generic Routing Encapsulation) protocol or IPsec protocol is used instead of the router 40 operating as a local gateway. The local gateways (GW) 60-1 and 60-2 to be connected are configured.

  Also in the second embodiment, for example, an IP packet sent from each of a plurality of terminal devices 11-1a and 11-1b belonging to the network module 10-1 to another terminal device 11-2a having a public remote address is transmitted through the LAN 12-1. Then, it is sent to the local GW 60-1. For this reason, IP packets from one or a plurality of terminal devices 11-1a and 11-1b can be aggregated in the local GW 60-1. The same applies to the local GW 60-2.

  Therefore, the communication between the network modules 10-1 and 10-2 is aggregated into the communication between the corresponding local GWs 60-1 and 60-2, and each of the local GWs 60-1 and 60-2 has a public local address and It is possible to control all communication between the network modules 10 by extracting IP packets that are responsible for communication between public remote addresses.

  The terminal device 11-1a of the first network module 10-1 has an IP address 192.168.20.2, which is one of public local addresses according to predetermined module basic information, a network address 192.168.20.0, and a netmask 255.255. Connected to the LAN 12-1 of 255.0, and communicates with the terminal device 11-2a having the IP address 192.168.30.2, which is one of the public remote addresses, via the local GW 60-1 having the IP address 192.168.20.1.

  Similarly, the terminal device 11-2a of the second network module 10-2 has an IP address 192.168.30.3 which is one of public local addresses according to predetermined module basic information, a network address 192.168.30.0, and a network Connect to LAN 12-2 with mask 255.255.255.0 and communicate with terminal device 11-1a having IP address 192.168.20.3, which is one of the public remote addresses, via local GW 60-2 having IP address 192.168.30.1 I do.

  The terminal device 11-1b of the first network module 10-1 and the terminal device 11-2b of the second network module 10-2 also have a unique IP that is one of public local addresses according to predetermined module basic information. Have an address.

  In the data communication system 2 of the second embodiment, the local GW 60-2 connected to the second network module 10-2 to be connected to the local GW 60-1 is connected using a tunnel protocol such as the GRE protocol or the IPsec protocol. When switching the second network module 10-2 of the connection partner to another network module 10, the connection using the tunnel protocol with the local GW 60-2 of the current connection partner is once disconnected, and the network module to be newly connected is The connection using the local GW (not shown) to be connected and the tunnel protocol is started.

  In this way, by switching the tunnel protocol connection, it is possible to perform connection destinations collectively without setting communication connection destinations for each terminal device.

  Therefore, the data relay apparatus 10 (first embodiment) having an interface connected in association with each individual network module, or a router that operates as a local GW 60-1, 60-2 interconnected using a tunnel protocol. Is configured as a network module relay device that relays IP packets communicated between individual network modules via an IP network.

  In the method using the tunnel protocol as in the second embodiment, IP packets exchanged between the terminal device 11-1a and the terminal device 11-2a are exchanged between the local GW 60-1 and the local GW 60-2. Store in packet and relay. Since the IP header of the IP packet requires the IP address of the local GW 60-1 or the local GW 60-2, the length of the relayed IP packet is longer than that of the original IP packet. Here, since there is an upper limit on the length of the packet that can be transmitted in the IP network 50, the length of the IP packet exchanged between the terminal device 11-1a and the terminal device 11-2a is the IP header to be added, etc. It is necessary to limit the amount of information short.

  For this reason, in the data communication system 2 of the second embodiment, if the packet is shortened, the transmission efficiency is lowered, and the number of packets is increased, so that the load on the terminal device is increased. In the data communication system 2 according to the second embodiment, the local GWs 60-1 and 60-2 increase the processing load because the IP packets are stored and extracted, so that transmission delay and transmission jitter are likely to increase. There is a drawback.

  On the other hand, the data communication system 1 according to the first embodiment described above is advantageous in that these disadvantages in the data communication system 2 according to the second embodiment can be eliminated because the network module is switched by rewriting addresses. It becomes.

  The present invention is not limited to the above-described embodiments, but is limited only by the description of the scope of claims.

  According to the present invention, it is possible to easily switch communication destinations related to data transmission of live video and the like, which is useful for use in a data communication system that enables data transmission of live video and the like.

1, 2 Data communication system 10-1 First network module 10-2 Second network module 10-3 Third network module 11-1, 11-2, 11-3 Terminal devices 11-1a, 11-1b, 11- 2a, 11-2b Terminal equipment 12-1, 12-2, 12-3 LAN
20-1, 20-2, 20-3 Data relay device 21 LAN interface 22 Address conversion unit 23 LAN interface 24 Mapping information storage unit 25 Connection control unit 30-1 First connection network 30-2 Second connection network 30-3 Third connection network 40-1, 40-2, 40-3 Router 50 IP network 60-1, 60-2 Local gateway (GW)
100 matrix switcher 200,300 data communication system

Claims (6)

In a data communication system in which predetermined data can be transmitted live between each terminal device to be interconnected, and a communication destination related to the data transmission can be switched without changing the communication setting of each terminal device. A terminal device that communicates using packets,
It is defined to have an IP address included in a range of public local addresses according to predetermined module basic information together with a communication destination terminal device to be interconnected. The module basic information includes a predetermined network address, netmask, local A GW address, a public local address, and a public remote address. The public local address defines an address value included in a network segment defined by the network address and the netmask, and the public remote address is the network address. And an address value not defined in the network segment defined by the netmask. The set of terminal devices according to claim 1, which is grouped by setting addresses in common for the module basic information, is configured as a network module,
A first interface for connecting the network module via a LAN;
A second interface for relaying, via an IP network, an IP packet communicating with the network module to which the communication destination terminal device to be interconnected belongs;
A network module relay device comprising: The set of terminal devices according to claim 1, which is grouped by setting addresses in common for the module basic information, is configured as a network module,
A first interface for connecting the network module via a LAN;
A mapping information storage unit that stores and holds mapping information including a public local address, a mapped local address, a public remote address, and a mapped remote address;
A connection control unit capable of updating the mapping information based on an external instruction;
Using the mapping information, the destination IP address of the IP packet is converted from the public remote address to the mapped remote address, the source IP address is converted from the public local address to the mapped local address, or the destination IP address is converted to the mapped local address. An address conversion unit that converts a source IP address from a mapped remote address to a public remote address,
A second interface for relaying, via an IP network, an IP packet communicating with the network module to which the communication destination terminal device to be interconnected belongs;
A data relay device comprising:   The address conversion unit further stores and holds a local GW address and mapped GW address information as the mapping information, and uses the mapping information to change the target protocol address of the ARP packet from the local GW address to the mapped GW address. Means for converting a protocol address from a public local address to a mapped local address, or converting a target protocol address from a mapped local address to a public local address, and a source protocol address from a mapped GW address to a local GW address. The data relay device according to claim 3, further comprising: A data relay device according to claim 3 or 4,
A network module connected using the data relay device;
Each of the data relay devices connected to the IP network establishes a connection by address translation between the terminal device belonging to the first network module and the terminal device belonging to the second network module, and A data communication system characterized in that data can be transmitted live and a communication destination related to the data transmission can be switched without changing the communication setting of each terminal device. A network module relay device according to claim 2;
A network module connected using the network module relay device;
Each network module relay device connected to the IP network establishes a connection by a tunnel protocol between the terminal device belonging to the first network module and the terminal device belonging to the second network module. The data communication system is characterized in that the data can be transmitted live and the communication destination for the data transmission can be switched without changing the communication setting of each terminal device.