JP2010263303A - System, method and program for address conversion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To designate a communication line to which communication data is to be transmitted and transmit the data. <P>SOLUTION: An address conversion system includes a communication relay means 31 connected to an external device via a plurality of different communication lines and a communication card C33 communicating with the external device. The communication relay means 31 has: a function of writing information showing a communication line via which communication data from the external device has been transmitted to the communication relay means 31, into the communication data; and a function of determining a communication line via which communication data from the communication card C33 should be transmitted to the external device, on the basis of route line identification information included in the communication data. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an address conversion system that performs destination conversion of communication data transmitted and received on a network such as the Internet.

  In data communication (Ethernet communication) between communication devices connected via Ethernet (Ethernet: registered trademark) as a physical interface, a communication relay device that relays the data communication includes a destination included in communication data to be transmitted and received Data communication is realized by performing address conversion.

Here, for example, the host device A, the network termination unit, the layer 2 switch, and the card C are connected as shown in FIG. 6, and the host device A and the card C are connected via the network termination unit and the layer 2 switch. Ethernet communication shall be performed.
At this time, the network terminating unit performs data termination of Ethernet communication between the host device A and the card C, and when the host device A performs communication of the Ethernet frame with the card C via the line # 1, It is assumed that address conversion is performed between an Ethernet address for communication with A (external communication) and an Ethernet address for internal communication performed between the network termination unit and the card C via a layer 2 switch.

  As a result, data packets called IP datagrams are distributed from the network interface of the transmission source host (higher level device A) to the network interface of the transmission destination host (card C) by the Internet Protocol (IP).

  The operation of Ethernet communication (data communication) in the host device A and card C will be described below with reference to FIG.

  First, the host device A in a configuration including a network termination unit that is connected to the host device A that transmits an Ethernet frame to the card C via the line # 1 and performs termination processing, a layer 2 switch, and the card C. The Ethernet address (EMAC address) is “# 5”, the Ethernet address on the line # 1 side of the apparatus B connected to the upper apparatus A via the line # 1 is “# 7”, and the network in the apparatus B at the network termination unit The Ethernet address for the card C is “# 20”, and the Ethernet address of the card C is “# 30”.

  Further, it is assumed that the host device A, the network termination unit, and the card C all have the same IP address as the Ethernet address (EMAC address). The IP address is an address prepared for identifying each terminal unit in the IP layer, like the Ethernet address.

  Here, first, the header information of the Ethernet frame in the Ethernet communication with the higher-level device A as the transmission source and the card C as the transmission destination is the Ethernet address and IP of the higher-level device A as the transmission source, as shown in status 1 of FIG. The address is “# 5”, and the address of the line # 1 of the transmission destination apparatus B is “# 7”.

  This Ethernet frame is sent (inputted) to the network termination unit, and the network termination unit is an Ether frame addressed to itself (network termination unit) from the destination Ethernet address “# 7” in the address conversion unit set in advance inside. Recognize that there is.

Here, the address conversion unit uses the destination IP address “# 7” and recognizes that this Ethernet frame is addressed to the card C based on a preset conversion table. Since the Ethernet address and the IP address are “# 30”, the transmission destination address is converted to “# 30” (status 2: FIG. 6).
Further, for this Ether frame, since the transmission source is changed from the higher-level device A to the network termination unit, the address conversion unit changes the transmission source Ethernet address from the higher-level device A “# 5” to the network termination unit “# 20”. Convert (status 2: FIG. 6).

As a result, the Ether frame in which the addresses of the transmission source and the transmission destination are converted is transmitted to the card C via the layer 2 switch.
Next, the card C performs Ethernet communication using the card C as a transmission source and the host device A as a transmission destination. At this time, as shown in status 3 in FIG. 6, the card C has “# 30” indicating the address of the card C as the source Ethernet address as the header information of the Ethernet frame, and a layer 2 switch as the destination Ethernet address. "# 20" indicating the network termination part on the side is assigned.

The network termination unit 31 receives an Ethernet frame from the card C via the layer 2 switch, and a preset address reverse conversion unit
From the source Ethernet address and the IP address, it is detected that the Ether frame is from the card C, and the destination Ethernet address, the source Ethernet address and the IP address are determined based on the preset address reverse conversion table and reversely converted. Perform the process.

At this time, as shown in status 4 in FIG. 6, the network termination unit uses “# 5” indicating the address of the higher-level device A as the transmission source Ethernet address and the network address as the transmission destination Ethernet address as the header information of the Ethernet frame. Assign “# 7” indicating the network termination.
As a result, the Ethernet frame in which the addresses of the transmission source and the transmission destination are reversely converted is transmitted to the upper apparatus A via the line # 1.

Next, as shown in FIG. 7, consider a communication operation in which the above-described host apparatus A and the network termination unit are connected by different communication lines (lines # 1, # 2).
At this time, it is assumed that the network termination unit includes independent network interfaces set corresponding to the lines # 1 and # 2, respectively.
Further, as shown in FIG. 7, # 9 is set in advance as an IP address and an EMAC address in the network on the line # 2 side in the network termination unit.

  Here, when communication is performed from the upper apparatus A via the line # 1 or the line # 2 with the card C using the Ethernet frame, the Ethernet communication performed via the line # 1 is described above and illustrated in FIG. The communication operation is performed as follows.

  Further, the Ethernet communication performed from the upper apparatus A to the card C via the line # 2 is the same as the Ethernet communication performed via the line # 1 as shown in the status 10 and the status 11 in FIG. A communication operation is performed.

The operation of Ethernet communication performed using the card C as a transmission source and the higher-level device A as a transmission destination will be described below.
Here, first, as shown in the status 12 of FIG. 7, the card C has its own card address “# 30” as the transmission source address and the net network termination unit as the transmission destination Ethernet address, as the header information of the Ethernet frame. “# 20” is assigned, and the Ethernet frame is transmitted to the network termination unit via the layer 2 switch.

  When this ether frame is sent to the network termination unit via the layer 2 switch, the network termination unit (address reverse conversion unit) detects that the ether frame is sent from the card C and sets it in advance. A destination Ethernet address, a source Ethernet address, and an IP address are determined based on the address reverse conversion table.

  At this time, the network termination unit assigns “# 5” indicating the address of the upper apparatus A to the source Ethernet address (EMAC address) as the header information of the Ethernet frame, as shown in the status 13 of FIG. As the destination Ethernet address, “# 7” indicating the network termination part on the line # 1 side is assigned.

  As described above, the network termination unit cannot assign the line # 2 (address # 9) as the transmission destination to the header information of the Ethernet frame at the time of address conversion. Can no longer be sent.

As a technique related to this, a method of reading header information of an Ethernet frame and connecting to the transmission destination physical line is disclosed (Patent Document 1).
Furthermore, as a related technique for this, a technique is disclosed in which a destination of a transmission destination is converted to an address and added to an Ethernet frame received through an Ethernet line (Patent Document 2).

Japanese Patent Application No. 7-162456 JP 2003-143236 A

  However, in the related technology, as described above, the Ethernet address and the IP address in the reversely converted Ether frame cannot specify the line # 2 (IP address # 9, EMAC address # 9) as the transmission destination. In addition, since the same transmission destination address as that of the line # 1 is assigned, there is a disadvantage that the Ethernet frame cannot be transmitted to the line # 2.

  In the related arts of Patent Documents 1 and 2 described above, when communication devices connected in parallel to a plurality of different communication lines connected in parallel transmit communication data, communication data is selected from the communication lines. There is an inconvenience that it is not possible to select and specify a specific communication line on which is transmitted.

[Object of invention]
The present invention provides an address conversion system, an address conversion method, and an address conversion program capable of effectively selecting and specifying a communication line through which communication data is transmitted when communication data is transmitted, by improving the disadvantages of the related art. Is the purpose.

  In order to achieve the above object, an address translation system according to the present invention includes a communication relay unit connected to an external device that transmits and receives communication data via a plurality of different communication lines, and the communication relay unit through the communication relay unit. An address conversion system including an intercommunication device that performs mutual communication with an external device, wherein the communication relay unit performs communication address conversion in communication data sent from the external device, and the communication data The communication information sent from the intercommunication device and the line information writing function for writing in the communication data the route identification information indicating the communication line through which the communication data is sent to the communication relay means A transmission line determination function for determining a communication line to be transmitted to the external device based on the transit line identification information included in the communication data; When the mutual communication device replies communication data with respect to the communication data from the communication relay means, the communication to which the transit line identification information included in the communication data from the communication middle means is added It has a configuration with a transit line specification function that generates data.

  The address conversion method according to the present invention includes a communication relay unit connected to an external device that transmits and receives communication data via a plurality of different communication lines, and the external device via the communication relay unit. An address conversion system including an intercommunication device that performs mutual communication, the intercommunication address conversion method, wherein the communication relay unit performs communication address conversion in communication data sent from the external device In addition, the communication line identification information indicating the communication line through which the communication data is sent to the communication relay means is written to the communication data, and the communication data is transmitted to the mutual communication device. When the communication data is replied to, the communication data with the transit line identification information included in the communication data is generated, and the communication data Is transmitted to the communication relay device, a communication line for sending communication data from the mutual communication device to the external device is determined based on the line identification information included in the communication data, and the transmission communication data is transmitted. It is characterized by that.

  Furthermore, an address conversion program according to the present invention is provided between a communication relay unit connected via a plurality of different communication lines to an external device that transmits and receives communication data, and the external device via the communication relay unit. An address conversion system including an intercommunication device that performs mutual communication, an address conversion program that transmits and receives the communication data, performs communication address conversion in communication data sent from the external device, and A line information writing function for writing in the communication data the line identification information indicating the communication line through which the communication data is sent to the communication relay means with respect to the communication data, the communication data sent from the mutual communication device Is determined based on the line identification information set in advance in the communication data. Delivery line determination function of, the characterized in that to execute a preset computer to the communication relay means.

  Since the present invention is configured and functions as described above, via-line identification information indicating the communication line through which the communication data is sent to the communication relay unit with respect to the communication data sent from the external device is provided. A line information writing function for writing to the communication data, and a transmission line determination function for determining a communication line as a transmission destination of the communication data sent from the mutual communication device based on the transit line identification information included in the communication data. As a result, it is possible to designate a communication line through which communication data is transmitted when communication data is transmitted, and to perform effective communication control.

It is a schematic block diagram which shows one Embodiment of the address translation system by this invention. It is a schematic block diagram which shows an example of an internal structure of the network termination | terminus part in the address translation system disclosed in FIG. It is explanatory drawing which shows the content of the header conversion process in the address conversion system disclosed in FIG. It is explanatory drawing which shows the content of the header conversion process in the address conversion system disclosed in FIG. It is explanatory drawing which shows the example of 1 structure of the Ethernet frame in the address translation system disclosed in FIG. It is explanatory drawing which shows the header conversion process in the related technology of the address translation system by this invention. It is explanatory drawing which shows the header conversion process in the related technology of the address translation system by this invention.

[Embodiment]
FIG. 1 shows a configuration diagram of an address translation system of the present invention.
As shown in FIG. 1, the address translation system according to the present embodiment includes an Ethernet between a host device A1 that performs Ethernet communication, a network 2 that is connected to the host device 1 via a communication line, and a host device A1. A device B3 having cards C33 and D34 for communicating therein is connected to the network 2 via lines # 1 and # 2 which are Ethernet (registered trademark) lines as physical interfaces.

The device B3 includes a network termination unit 31 that terminates data (hereinafter referred to as “Ethernet frame”) sent by the Ethernet communication performed with the host device A1 and the Ethernet, and an Ethernet frame in the network in the device B. A layer 2 switch that performs routing control is provided.

  The device B3 includes a card C33 and a card D34 that transmit an Internet Protocol (IP) data packet called an IP datagram in the device B3.

In the present embodiment, data communication inside the device B3 is also performed by Ethernet communication. Thereby, connectivity with communication (external network) between the upper apparatus A and the apparatus B is maintained.
In Ethernet communication, a unique identifier is assigned in advance to each network interface (of a connected device), and is designated using this identifier as a destination of a signal (communication data).
For this reason, a 48-bit identifier called “Ethernet address” is used for each network interface, and each Ethernet address is fixed to the hardware of each network interface.

  As shown in FIG. 5, the data structure of the Ethernet frame includes a preamble (64 bits), a destination address (48 bits) indicating the destination Ethernet address, and a source address (48) indicating the Ethernet address of the source itself. Bit), a frame type (16 bits) that is an area for storing the identification number of the upper protocol, data (1500 bytes) in which the data content of the Ethernet frame is stored, and CRC “Cyclic Redundancy Check” (32 bits) included.

It is assumed that the network interface of the transmission destination (here, the network termination unit 31) can recognize what protocol the data stored in the data field (data area) of the Internet frame is.
Thereby, for example, when the frame type of the sent Internet frame is “0800 (Hex)”, the network interface can identify that the upper layer protocol is IP. (Hex) indicates hexadecimal notation.

  As shown in FIG. 1, the device B3 is connected to the network 2 via two different lines (Ethernet lines: # 1 and # 2).

  In addition, the device B3 includes a network termination unit 31 as a network interface therein, and the network termination unit 31 performs an Ethernet frame termination process in Ethernet communication with the host device A1 (Ethernet termination processing function).

The network termination unit 31 includes network interfaces corresponding to the different Ethernet lines (# 1 and # 2), and a unique Ethernet address is assigned to each network interface.
As a result, the device B3 is connected to the host device A1 via different network interfaces that are installed independently for the lines # 1 and # 2.

The network termination unit 31 is also connected to a network (internal network) 30 set inside the device B3 via an Ethernet line.
Further, the network termination unit 31 has a network address conversion function for converting an Ethernet address between the network 2 (external network) and the internal network 30.

The device B3 includes a layer 2 switch 32 that performs Ethernet frame routing control in the internal network 30, and transmits and receives data (ether frame) via the layer 2 switch 32.
In addition, the device B3 includes a card C33 and a card D34 that perform an IP termination process that is a higher-level protocol.
Further, the device B3 forms the internal network 30 with the internal network 30 by the layer 2 switch 32, the card C33, and the card D34.

As shown in FIG. 2, the network termination unit 31 includes a reception buffer 311 that stores an Ethernet frame transmitted from the host apparatus A1 and sent via the line # 1, and an Ethernet address of the Ethernet frame stored in the reception buffer 311. Is converted to an Ethernet address (internal address) for the internal network 30 of the device B3.
In addition, the network termination unit 31 specifies whether the Ethernet frame is input from the line # 1 or # 2, and inserts information indicating the line into the frame type, the frame type conversion unit 315, A transmission control unit 317 is provided to send the Ethernet frame passed from 316 to the layer 2 switch 32.

Furthermore, the network termination unit 31 stores the Ethernet frame transmitted from the host apparatus A1 and sent via the line # 2, and the Ethernet address of the Ethernet frame stored in the reception buffer 312 is stored in the apparatus B3. It has an address conversion unit 314 that converts it into an Ethernet address (internal address) for the network 30.
Further, the network termination unit 31 specifies whether the Ethernet frame passed from the address conversion unit 314 is input from the line # 1 or # 2, and inserts information indicating the line into the frame type. 316.

Further, the network termination unit 31 receives the Ethernet frame sent from the layer 2 switch 32, and the Ethernet frame from which the Ethernet frame from the reception control unit 318 is sent out from either the line # 1 or # 2. And a frame type reverse conversion unit 320 that passes to the address reverse conversion unit for the specified line.
Further, the network termination unit 31 converts the Ethernet address of the Ethernet frame from the frame type reverse conversion unit 320 according to the transmission destination (for example, the host device A1), and the line reverse address conversion unit 321 for the line # 1 and the line # 2. Address reverse conversion unit 322, a transmission buffer 323 that acquires and temporarily stores an Ether frame delivered from address reverse conversion unit 321 and sent to line # 1, and a line passed from address reverse conversion unit 322 The configuration includes a transmission buffer 324 that acquires and temporarily stores the Ethernet frame transmitted to # 2.

  The network termination unit 31 can be handled by software processing instead of hardware. The line number is not assigned to the Ethernet frame field type, but can be included in the IP, address, port number, data area, etc., and can be handled by a higher-level protocol.

[Description of Operation of Embodiment]
Next, the operation of the above embodiment will be outlined.
First, the network termination unit 31 performs communication address conversion on the communication data sent from the higher-level device 1 and communicates via-line identification information indicating the communication line through which the communication data was sent to the network termination unit 31. Write to the data, transmit this communication data to the card C, and when the card C replies to this communication data, generate communication data with the transit line identification information included in the communication data, The network termination unit 31 determines a line for sending the communication data to the host apparatus A1 based on the line identification information included in the communication data, and transmits the communication data.

  Here, regarding the line information writing process and the transmission line determination process, the execution contents may be programmed and executed by a computer.

Next, the operation of the above embodiment will be described in detail with reference to FIGS.
First, data communication (Ethernet communication) in the card C33 in the device B3 and the host device A1 connected via the line # 1 will be described with reference to FIG.
Here, Ethernet communication between the card C33 and the host device A1 will be described, but it is assumed that Ethernet communication between the card C34 and the host device A1 can be executed in the same manner.

In the present embodiment, as shown in FIG. 3, the EMAC address (Ethernet address) of the host device A1 is “# 5”, the Ethernet address on the line # 1 side of the device B3 is “# 7”, and the network termination unit 31 internal It is assumed that the Ethernet address for the network 30 is “# 20” and the Ethernet address of the card C is “# 30”.
Further, it is assumed that the line # 1, the network termination unit 31, and the card C33 in the host device A1 and the device B3 each have the same IP address as the Ethernet address (EMAC address).

In addition, this IP address is an address for identifying each terminal unit in the IP layer like the Ethernet address.
The frame type (Type field) “0800 (Hex)” of this Ethernet frame indicates that the upper protocol is IP. (Hex) indicates hexadecimal notation.

First, the Ethernet frame transmitted from the upper apparatus A1 to the card C33 is sent to the network termination unit 31 via the line # 1. Here, the Ethernet frame is transmitted via the line # 1, and is input to the network termination unit 31 of the device B3.
Next, the address conversion unit 313 of the network termination unit 31 recognizes (detects) from the transmission destination address “# 7” included in the Ethernet frame that the Ethernet frame is an Ethernet frame addressed to itself.
Next, the address conversion unit 313 detects that this Ether frame is addressed to the card C based on a preset address conversion table (hereinafter referred to as “conversion table”) using the destination IP address “# 7”. Address conversion is performed for the Ethernet (internal network 30) in the device B3.

Here, since the Ethernet address and IP address of the card C are “# 30”, the address conversion unit 312 converts the transmission destination address of the Ethernet frame to “# 30”.
For this Ethernet frame, since the transmission source is changed from the higher-level device A to the network termination unit 31, “# 5” indicating the higher-level device A as the transmission source Ethernet address is replaced with the internal network 30 in the network termination unit 31. Side is converted to “# 20” indicating the Ethernet address on the side.

Next, the frame type conversion unit 315 adds the line number “0001 (Hex)” input by the higher-level device A1 to the field type area of the ether frame for which address conversion has been completed. (Hex) indicates hexadecimal notation.
As a result, the field type of the Ether frame transmitted to the network (internal network) 30 in the device B3 is “0801 (Hex)”. Status 2 in FIG. 3 shows an Ethernet frame configuration in the internal network 30 in the device B3. (Hex) indicates hexadecimal notation.

  Next, since the transmission destination address in the ether frame is “# 30”, the card C33 recognizes that it is an ether frame addressed to itself (self card), and from the field type “0801 (Hex)”. The Ethernet frame is recognized (detected) as frame data input from the line # 1 connected to the device B3. (Hex) indicates hexadecimal notation.

  Here, the card C33 assigns its own card address “# 30” as the source address. Further, “# 20” indicating the network termination unit 31 is input as the destination Ethernet address, and “0801 (Hex)” indicating the line # 1 is input as the field type. (Hex) indicates hexadecimal notation.

  The network termination unit 31 detects from which line number the Ethernet frame needs to be transmitted from the field type of the Ethernet frame received from the layer 2 switch 32, and an address reverse conversion unit (321 or 321 based on the line number). The Ethernet frame is passed to 322).

At this time, the field type is rewritten to “0800 (Hex)”. (Hex) indicates hexadecimal notation.
The address reverse conversion unit 321 detects that the Ethernet frame is from the card C33 from the transmission source Ethernet address and the IP address, and based on a preset address reverse conversion table, the transmission destination address, the transmission source address, and the IP address Determine the address. Status 4 in FIG. 3 shows the Ethernet address and IP address contents after reverse conversion.

  As described above, when the host device A1 and the device B3 are connected via the line # 1 as shown in FIG. 3, the network termination unit 31 performs address conversion to perform Ethernet communication with each other. be able to.

Next, the Ethernet communication operation between the card C33 of the device B3 and the host device A1 performed when the host device A1 and the device B3 are connected via the line # 1 and the line # 2, as shown in FIG. Will be described with reference to the explanatory diagram of FIG.
It is assumed that “# 9” is assigned in advance as the EMAC address and IP address of the network interface on the line # 2 side in the network termination unit 31.

Here, it is assumed that the Ethernet communication performed via the line # 1 in this embodiment operates as described above (FIG. 3).
Hereinafter, an operation of Ethernet communication performed via the line # 2 in the present embodiment will be described.

First, the Ethernet frame transmitted from the host device A1 to the card C33 is sent to the network termination unit 31 via the line # 2.
Next, the address conversion unit 313 of the network termination unit 31 recognizes (detects) that the Ethernet frame is an Ethernet frame addressed to itself from the transmission destination address “# 9” included in the Ethernet frame (Ethernet frame). .
Here, the address conversion unit 313 detects that this Ether frame is addressed to the card C based on a preset address conversion table (hereinafter referred to as “conversion table”) using the destination IP address “# 9”. Then, address conversion for the Ethernet (internal network 30) in the device B3 is performed.
Here, the address conversion unit 313 performs address conversion corresponding to the Ethernet (internal network 30) in the device B3 with respect to the ether frame addressed to the card C33 input to the line # 2 (statuses 10 and 11 (FIG. 4). )).

At this time, since the EMAC address and the IP address of the card C33 are “# 30”, the address conversion unit 314 converts the destination address of the Ethernet frame to “# 30”.
In addition, since the transmission source of the ether frame is changed from the higher-level device A to the network termination unit 31, the address conversion unit 314 changes the transmission-source Ethernet address from the higher-level device A “# 5” to the network on the internal network 30 side. The address is converted to an address “# 20” indicating the end portion 31.

Next, with respect to the value “0800 (Hex)” of the field type area (Type field) of the ether frame in which this address conversion is completed, the frame type conversion unit 316 indicates the line # 2 input by the host apparatus A1. A process of adding the line number “0002 (Hex)” to the line number (line identification number assigning function) is performed. (Hex) indicates hexadecimal notation.
Thereby, the field type of the Ethernet frame transmitted to the internal network 30 is set to “0802 (Hex)” as shown in the status 11 (FIG. 4). (Hex) indicates hexadecimal notation.

  Next, the Ethernet frame is transmitted to the internal network 30 by the transmission control unit 317 and sent to the card C33 via the layer 2 switch 32.

  Next, a communication operation using the card C33 as a transmission source and the host device A as a transmission destination will be described.

First, the card C33 generates an Ethernet frame addressed to the higher-level device A1.
Here, similarly to the status 3, the card C33 assigns its own card address “# 30” to the source address, and assigns “# 20” indicating the network termination unit 31 to the destination Ethernet address. It shall be.
Also, the card C33 inputs “0802 (Hex)” indicating the line # 2 set as described above as the field type of the Ethernet frame. (Hex) indicates hexadecimal notation.

  Next, the card C33 transmits the generated Ethernet frame to the network termination unit 33 via the layer 2 switch 32. The reception control unit 318 of the network termination unit 31 receives the Ethernet frame and passes it to the frame type inverse conversion unit 320.

Next, the frame type inverse conversion unit 320 detects from the field type (0802 (H)) of the ether frame that the ether frame is an ether frame transmitted from the line # 2 (destination line detection function), and detects it. The Ethernet frame is transferred to the address reverse conversion unit 322 based on the line number (here, line # 2 is indicated).
Here, the frame type inverse conversion unit 320 detects that the Ether frame is an Ether frame transmitted to the line # 1 from the field type of the Ether frame, that is, indicates the line # 1 as the field type. If “0801 (Hex)” is input, this Ethernet frame is transferred to the address reverse conversion unit 321. (Hex) indicates hexadecimal notation.

Next, the address reverse conversion unit 322 for the line # 2 is based on the preset address reverse conversion table, and the transmission destination Ethernet address, the transmission source Ethernet address in the Ethernet frame passed from the frame type reverse conversion unit 320, and Reverse translation of IP address (address reverse translation function).
Here, as shown in statuses 12 and 13 (FIG. 4), the transmission source IP address and the transmission source EMAC address are converted to “# 9”, and the transmission destination EMAC address is converted to “# 5”.
Next, the Ethernet frame whose address has been reversely converted is read into the transmission buffer 324 and transmitted to the upper apparatus A1 via the line # 2 together with the frame.

  As described above, in this embodiment, in the network termination unit 31 that terminates the two Ethernet lines (# 1, # 2) connected to the apparatus, each Ethernet line is connected from the same external apparatus (higher-level apparatus A1). From the in-device card (33, 34) by writing the physical line number in the frame type area of the ether frame at the time of address conversion to transfer the ether frame sent through the card to the card C33 in the device B3. The destination physical line of the Ethernet frame to be transmitted to the upper apparatus A1 can be designated.

  In addition, Ethernet frames are transmitted / received to / from communication cards (cards C and D: equivalent to mutual communication devices) set in the device B3 between the host device A1 and the device B3 connected via a plurality of different lines. In this case, the Ethernet frame transmitted from the card to the higher-level apparatus A can be transmitted using the same line as the line where the apparatus B receives the Ethernet frame from the higher-level apparatus. This also ensures independence of the communication line.

Further, by writing information indicating the transmission destination physical line in the frame type (area) of the Ethernet frame, it is possible to specify the transmission destination physical line of the Ethernet frame.
As a result, the network termination unit 31 in the device B3 can be supported by supporting only the Ethernet frame of the physical layer. For this reason, it is not necessary to implement an upper protocol higher than IP, and Ethernet communication can be easily realized only by the physical layer which is the basic implementation.

  The present invention can be applied to a communication system including a communication device that performs parallel connection to different communication lines.

1 Host device A
2 Network 3 Device B
30 Internal Network 31 Network Termination Unit 32 Layer 2 Switch 32
33 Card C
34 Card D
311 and 312 Reception buffer 313 and 314 Address conversion unit 315 and 316 Frame type conversion unit 317 Transmission control unit 318 Reception control unit 320 Frame type reverse conversion unit 321 and 322 Address reverse conversion unit 323 and 324 Transmission buffer

Claims (5)

Communication relay means connected via a plurality of different communication lines to an external device that transmits and receives communication data, and a mutual communication device that performs mutual communication with the external device via the communication relay means An address translation system,
The communication relay means performs communication address conversion in communication data sent from the external device, and indicates a communication line through which the communication data is sent to the communication relay means with respect to the communication data A line information writing function for writing identification information to the communication data;
A transmission line determination function for determining a communication line for transmitting communication data sent from the mutual communication device to the external device based on transit line identification information included in the communication data;
When the mutual communication device returns communication data to the communication data from the communication relay means, the communication data to which the transit line identification information included in the communication data from the communication middle means is added An address conversion system characterized by having a function of specifying a transit line to be generated. The address translation system according to claim 1,
The address conversion system, wherein the communication line is configured by Ethernet (registered trademark). In the address translation system according to claim 1 or 2,
A communication device comprising the communication relay means and the mutual communication device;
The communication device includes an internal communication control unit that relays communication between the communication relay unit and the intercommunication device and routes communication data sent from the communication relay unit and the intercommunication device. Address translation system. Communication relay means connected via a plurality of different communication lines to an external device that transmits and receives communication data, and a mutual communication device that performs mutual communication with the external device via the communication relay means In the address translation system, the intercommunication address translation method,
The communication relay means performs communication address conversion in the communication data sent from the external device, and also includes routed line identification information indicating the communication line through which the communication data was sent to the communication relay means. Write to the communication data and send the communication data to the mutual communication device,
When replying to the communication data, generate communication data with the transit line identification information included in the communication data, and transmit the communication data to the communication relay device,
A communication line for sending communication data from the mutual communication device to the external device is determined based on the line identification information included in the communication data, and the communication data from the mutual communication device is transmitted. Address translation method. Communication relay means connected via a plurality of different communication lines to an external device that transmits and receives communication data, and a mutual communication device that performs mutual communication with the external device via the communication relay means An address conversion system for transmitting and receiving the communication data, the address conversion program comprising:
In addition to performing communication address conversion on the communication data sent from the external device, the communication data is converted to the communication data indicating the communication line through which the communication data is sent to the communication relay means. Line information writing function to write to
A transmission line determination function for determining a communication line for transmitting communication data sent from the mutual communication device to the external device based on line identification information set in advance in the communication data is preset in the communication relay means. An address conversion program that is executed by a computer.

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