JP4243768B2 - Communication device - Google Patents

Description

  The present invention relates to a communication apparatus that is installed between a plurality of first communication networks and a second communication network having a communication protocol different from that of the first communication network and performs communication control.

  As a network system for transmitting various data, for example, an ATM (Asynchronous Transfer Mode) network, an Ethernet (registered trademark) network (hereinafter, referred to as a LAN (Local Area Network) or a wide area LAN) and the like are known. In the ATM network, data is converted into cells of 48 bytes, and a 53-byte cell with a 5-byte header added is transmitted, and the VPI (Virtual Path Identifier), VCI of the header of the cell is transmitted. According to (Virtual Channel Identifier), high-speed transmission is performed to the other party. In a LAN, a transmission destination address and a transmission source address are added to a header portion, and data is transmitted in a frame configuration. For example, 100BASE-FX, 100BASE-T, Specifications such as 1000BASE-LX, 1000BASE-SX, and 10GBASE-X are known.

In a LAN, a MAC (Media Access Control) address is assigned to a terminal device, and data is transmitted as a frame structure by using the MAC address as a transmission destination address. Further, in a wide area LAN, terminal devices located at geographically distant bases are connected via a bridge device or the like disposed at each base and having a required transmission capability. In addition, when an IP (Internet Protocol) packet with an undefined MAC address is efficiently transferred as communication data, an address table is provided in the bridge device, and a function for converting between an IP (Internet Protocol) address and a MAC address is provided. There is a way. When constructing the address table, as an address resolution unit that crosses between transmission layers, for example, a unit that acquires a MAC address of a transmission destination using ARP (Address Resolution Protocol) is known (for example, , See Patent Document 1).
JP 2002-319953 A

  The above-mentioned ATM network transmits cellular data in accordance with VPI / VCI added to the header and includes various advantages. However, the cost for maintaining a communication line connecting an ATM switch and a plurality of bases. However, the network system includes a problem of increasing the cost. On the other hand, the above-mentioned LAN has an advantage that a multipoint-to-multipoint communication line can be maintained at a relatively low cost and an expensive exchange is not included, so that the cost can be reduced. Therefore, it is proposed to construct a network system in which a part of the ATM network is configured by a LAN (particularly, a wide area LAN) and a plurality of ATM exchanges are connected via the LAN. A means for converting between VP1 / VCI added to the cell header in the cell and a MAC address added to the frame in the LAN, that is, an address resolution means is required.

  Therefore, it is conceivable to provide a MAC address management server. However, since the MAC address management server is relatively expensive and needs to be provided for an ATM switch, there is a problem that the cost cannot be sufficiently reduced even if a LAN is used. Note that the MAC address conversion of the bridge device in the above-described conventional example only shows a means for converting an IP address and a MAC address, and is not considered at all for the ATM network.

  The present invention solves the above-mentioned conventional problems, and has a relatively simple configuration and a relatively inexpensive configuration, so that a first communication network such as an ATM network and a second communication such as a LAN are provided. An object of the present invention is to provide a communication device that performs communication control with a network, thereby reducing costs and address resolution.

The communication device of the present invention is a communication device installed between a plurality of first communication networks having the same communication protocol and a second communication network having a communication protocol different from that of the first communication network. An address conversion table for storing a destination identifier used in the first communication network and a device identifier for identifying a data transmission destination device connected to the second communication network, and a first communication network Receiving data from the second communication network, and receiving device information corresponding to the destination identifier from the second communication network, when receiving data from the second communication network Receiving means; and storage means for storing device information received by the receiving means in an address conversion table in association with a destination identifier used in the first communication network .

  According to the present invention, in a network system in which a plurality of ATM networks are connected to a LAN by a converter device, the converter device has an address conversion table and a control processing unit, and a cell to be transmitted by the ATM network. Broadcasting a special frame corresponding to the external VPI / VCI indicating the destination and including the internal VPI / VCI uniquely assigned to the LAN and the MAC address of the own device to the LAN, and the internal of the special frame The converter device that has received and identified the VPI / VCI transmits a response frame having the transmission source MAC address of the special frame as the transmission destination MAC address and the MAC address of its own device as the transmission source MAC address to the LAN. The converter device receiving this response frame receives the external VPI. VCI and, with the internal VPI / VCI, it is also possible to include the steps of wearing the corresponding register set in the address conversion table the source MAC address of the response frame as a facing MAC address.

  A process of transmitting the special frame including the internal VPI / VCI in an IPv6 address to the LAN, and a process of receiving a response frame from a converter corresponding to the internal VPI / VCI and constructing the address conversion table. It can also be included.

  The converter device may include a process of periodically transmitting the special frame to the LAN, receiving a response frame for the special frame, and performing setting registration of the address conversion table.

  As a communication control method for a network system in which a plurality of ATM networks are connected to a LAN by a converter device, the converter device has an address conversion table, a counter VPI-MAC table, and a control processing unit, and is transmitted by the ATM network. The internal VPI / VCI uniquely assigned to the LAN and the opposite MAC address are set and registered in the address conversion table, and are registered in the opposite VPI-MAC table. The external VPI / VCI, the internal VPI / VCI, the destination MAC address for the opposing converter device via the LAN, and the opposing MAC address indicating its own MAC address are set and registered, and the opposing VPI- The internal VPI based on the setting registration contents of the MAC table A process of transmitting a special frame including a VCI, the destination MAC address, and a counter MAC address indicating the MAC address of the own device to the LAN, and a converter device that has received the special frame according to the destination MAC address, It is also possible to include a process of setting and registering the opposite MAC address of the special frame corresponding to the external VPI / VCI and the internal VPI / VCI in the address conversion table of the converter device.

  A communication device for connecting a first communication network such as an ATM network including a plurality of ATM exchanges via a second communication network such as a LAN has a relatively simple configuration including an address conversion table. The cost of the network system can be reduced, and the address resolution for transmitting the cell transmitting the ATM network as a frame by the LAN can be performed by the address conversion table. The address conversion table for address resolution can be efficiently and autonomously constructed by transmitting and receiving special frames such as VPI-MAC resolution frames.

  1 and 2, the communication device of the present invention includes a plurality of first communication networks having the same communication protocol and a second communication network having a communication protocol different from the first communication network. A communication apparatus installed between the destination identifier used in the first communication network and the device identifier for identifying the data transmission destination device connected to the second communication network A conversion table; means for casting destination information corresponding to a destination identifier included in the data when the data is received from the first communication network; and a destination from the second communication network. Receiving means for receiving device information corresponding to the identifier, and storing means for storing the device information received by the receiving means in the address conversion table in association with the destination identifier. For example, an external VPI / VCI indicating a destination of a cell transmitted through the ATM network, an internal VPI / VCI uniquely assigned to the LAN 3, and the opposing MAC addresses of the opposing converter devices 2-1 to 2-3 connected to the LAN 3. The address conversion table 24 for storing and the external VPI / VCI of the header of the cell from the ATM network is changed to the internal VPI / VCI with reference to the address conversion table 24, and the internal VPI / VCI is supported. A frame with the opposite MAC address added is converted and sent to the LAN 3, and the frame received from the LAN 3 is referred to the address conversion table 24 to remove the opposite MAC address of this frame, and the internal VPI / VCI is changed to the external VPI. Control to send the converted cell to / VCI to ATM network It may comprise a Cormorant control processor 21.

  As a communication control method for a network system in which a plurality of ATM networks are respectively connected to the LAN 3 by converter devices 2-1 to 2-3, the converter devices 2-1 to 2-3 include an address conversion table 24, a control processing unit 21, and the like. VPI-MAC resolution frame including the internal VPI / VCI uniquely assigned to the LAN and the MAC address of its own device, etc., corresponding to the external VPI / VCI indicating the destination of the cell transmitted by the ATM network The process of broadcasting the special frame to the LAN 3 and the converter device that has received and identified the internal VPI / VCI of this special frame uses the source MAC address of this special frame as the destination MAC address, and sets the MAC address of its own device. The process of sending a response frame with the source MAC address to LAN 3 and this The converter device that has received the response frame may include a process of registering and setting the external VPI / VCI, the internal VPI / VCI, and the source MAC address of the response frame in the address conversion table 24 in association with the opposite MAC address. it can.

  FIG. 1 shows an outline of a network system of the present invention, wherein 1-1 to 1-3 are ATM switches or an ATM network including an ATM switch, 2-1 to 2-3 are converter devices, and 3 is the above-described converter. 1 shows a LAN as an Ethernet (registered trademark) network. That is, the case of a network system configuration in which a plurality of ATM networks including ATM exchanges 1-1 to 1-3 are connected via converters 2-1 to 2-3 as communication devices and a LAN 3 is shown. It should be noted that a larger number of ATM exchanges may be provided and connected to each other via the LAN 3 via converter devices. It is also possible to configure part or all of the LAN 3 as a wide area LAN.

  FIG. 2 shows a main part of the converter device 2, which corresponds to the converter devices 2-1 to 2-3 in FIG. 1, wherein 21 is a control processing unit (CPU), 22 is an ATM switch 1-1. ... 1-3 are connected to an ATM interface unit (ATMIF), 23 is a LAN interface unit (LANIF) for connecting to the LAN 3, and 24 is an address conversion table.

  The control processing unit 21 is configured by a processor, and processing for cell transmission / reception control by the ATM interface unit 22, control processing such as writing to and reading from the address conversion table 24, and VPI / VCI (hereinafter referred to as a VPI / VCI) of a header indicating a cell destination A processing function including a change process (described as “VPI”), a process of adding a MAC address to a frame to be transmitted and a process of deleting a MAC address of a received frame, and a frame transmission / reception control by the LAN interface unit 23 It is. The address conversion table 24 sets an external VPI on the ATM network side, an internal VPI on the LAN side (a unique value in the LAN), and a MAC address, and after this setting is completed, The control processing unit 21 refers to the address conversion table 24 and associates the VPI with the MAC address, whereby data communication between ATM networks can be performed via the LAN.

  For the ATM exchanges 1-1 to 1-3, converter devices 2-1 to 2-3, and LAN 3 shown in FIG. 1, the MAC addresses of the converter devices 2-1 to 2-3 are set as shown in FIG. AAAA, BBBBB, and CCCCC, respectively, the external VPI in the converter device 2-1 is 100 and 101, the internal VPI is 70 and 71, the external VPI in the converter device 2-2 is 110, and the internal VPI is 70, The setting of the address conversion table 24 and the like will be described below assuming that the external VPI is 111 and the internal VPI is 71 in the converter device 2-3.

  In the first embodiment, when the address conversion table 24 is constructed, after setting the external VPI and the internal VPI in the address conversion table 24, the converter device uses the VPI-MAC resolution frame as a special frame. Is sent and received to perform MAC address setting registration. FIG. 4 is an explanatory diagram of this VPI-MAC resolution frame. FIG. 4A shows an example of a VPI-MAC resolution frame (Request) as a special frame, and FIG. An example of a VPI-MAC resolution frame (Reply) as a response frame to the frame is shown, and includes a destination MAC address, a source MAC address, a frame type (TYPE), a request type, and an internal VPI field.

  As shown in FIG. 4A, the VPI-MAC resolution frame as a special frame for acquiring the MAC address of the converter device facing through the LAN has a transmission destination MAC address as an address indicating broadcast, The source MAC address is the MAC address of the own device, the frame type is the VPI-MAC resolution type, the request type is Request indicating an address resolution request, and the internal VPI is an internal VPI uniquely set in the LAN. And

  In addition, as shown in FIG. 4B, the response frame to this VPI-MAC resolution frame is the MAC address of its own device with the source MAC address of the previously received VPI-MAC resolution frame as the destination MAC address. Is the source MAC address, the frame type is the VPI-MAC resolution type, the request type is Reply indicating a response, and the internal VPI is the internal VPI of the previously received VPI-MAC resolution frame.

  FIG. 5 shows a flowchart of the first embodiment of the present invention. FIGS. 6A and 6B show processing steps (1) of the converter device 2 for the MAC address resolution processing according to the flowchart of FIG. ) To (12) and will be described with reference to the configuration shown in FIGS. In FIG. 5, converter devices 2-1 to 2-3 are A, B, and C, respectively, and each address conversion table 24 sets an external VPI and an internal VPI as shown as 24a1, 24b1, and 24c1. However, in the state where the opposite MAC address for the converter device via the LAN is not set, the ATM interface unit 22 of the converter device A uses the ATM switch 1-1 (ATM network) with an external VPI: 100. A processing process when the cell is received will be described.

  When a cell from the ATM network is received by the ATM interface unit 22 of the converter apparatus A (1) (see FIG. 6A), the control processing unit 21 of the converter apparatus A is added to the header of the received cell. The address translation table 24a1 (see FIG. 5) is searched using the external VPI: 100 as a key (2).

  Since the opposite MAC address is not set in the address conversion table 24a1, the control processing unit 21 of the converter device A extracts the internal VPI: 70 corresponding to the external VPI: 100 (3), and the external VPI of the received cell header. : 100 is changed to this internal VPI: 70, a VPI-MAC resolution frame (Request) is generated (4), and is transmitted from the LAN interface unit (LANIF) 23 to the LAN (5). In this VPI-MAC resolution frame (Request), as shown in FIG. 4A, the transmission destination MAC address indicates broadcast, and the transmission source MAC address is the MAC address of its own device: AAAAA. This MAC address: AAAAA is recognized by the control processing unit 21 as the MAC address of its own device.

  When the converter devices B and C receive the VPI-MAC resolution frame (Request) via the LAN interface unit 23 (6) (see FIG. 6B), the control processing unit 21 receives the received VPI-MAC resolution frame. It is searched whether or not the internal VPI: 70 added to the frame (Request) is set in the address translation tables 24b1 and 24c1 (7). In the converter device B, since the internal VPI: 70 is set in the address conversion table 24b1 (see FIG. 5), the control processing unit 21 of the converter device B uses the internal VPI: 70 from the address conversion table 24b1. (8), and the VPI-MAC resolution frame (the source MAC address: AAAAA of the received VPI-MAC resolution frame is the destination MAC address, and the source MAC address is the MAC address of its own device: BBBBB ( (Reply) is generated (9) and transmitted from the LAN interface unit 23 (10). At that time, the content shown in 24b2 is obtained by setting the MAC address: AAAAA for the internal VPI: 70 in the address conversion table 24b1 of the converter apparatus B.

  In addition, since the internal VPI: 70 is not set in the address conversion table 24c1, the converter device C does not have the same VPI even if it receives the above-mentioned VPI-MAC resolution frame (Request). Not performed. Therefore, the address conversion table of the converter device C is shown in 24c2 which is the same as 24c1 (see FIG. 5). When the VPI-MAC resolution frame (Reply) from the converter device B is received (11) by the LAN interface unit 23 of the converter device A as indicated by the one-dot chain arrow in FIG. Sets the received MAC address: BBBBB in the address conversion table 24a1 in an area corresponding to the internal VPI: 70 (12).

  As a result, as shown in FIG. 5, the address conversion table 24 of the converter device A includes the MAC address: BBBBB of the converter device B corresponding to the external VPI: 100 and the internal VPI: 70, as shown as 24a2. In the address conversion table 24 of the converter apparatus B, the MAC address: AAAAA of the converter apparatus A is set corresponding to the external VPI: 110 and the internal VPI: 70, as shown as 24b2.

  In this state, the converter device A searches the address conversion table 24 (24a2) for the external VPI: 100 cell from the ATM network using the external VPI: 100 as a key, as described above. The internal VPI: 70 and the MAC address: BBBBB are read out, the external VPI: 100 in the header of the cell is changed to the internal VPI: 70, and the destination MAC address: BBBBB, the source MAC address: A frame with AAAAA added is generated, and the frame is sent to the LAN.

  In the converter apparatus B, the frame of the transmission destination MAC address: BBBBB is received as addressed to the own apparatus, the transmission destination MAC address: BBBBB and the transmission source MAC address: AAAAA are deleted, and the address conversion table 24 (24b2). Referring to FIG. 4, the ATM interface unit 22 transmits a cell in which the internal VPI: 70 is changed to the external VPI: 110 to the ATM switching network. Accordingly, it is possible to perform address resolution by transmitting a cell from the external VPI: 100 ATM network to the external VPI: 110 ATM network via the LAN. Also, the address conversion table 24 can be constructed by performing the above-described processing between the converter devices A and C and between B and C. Thereby, data communication between a plurality of ATM networks can be performed via the LAN.

  As described above, each of the converter devices A, B, and C can be realized with a relatively simple configuration including the address conversion table 24 that performs conversion between the VPI and the MAC address. As described above, the association between the VPI and the MAC address for all ATM networks can be executed by transmission / reception of a special frame such as a VPI-MAC resolution frame. Therefore, data communication between ATM networks connected by a LAN can be performed without providing a MAC address management server.

  FIG. 7 shows a flowchart of Embodiment 2 of the present invention, and shows a case where IPv6 (Internet Protocol Version 6) based on RFC (Request For Comments) 2373 is applied. FIG. 8 shows the address configuration of IPv6. As shown in FIG. 8A, the IPv6 address configuration has a 128-bit configuration, and includes a 64-bit network unit and a 64-bit host unit. The section is composed of a 48-bit public topology and an 18-bit site topology. FIG. 8B shows a case where the internal VPI is set to the site topology and the host part (interface ID) is all “1” and the broadcast is set.

  In FIG. 7, the converter devices 2-1 to 2-3 shown in FIG. 1 are designated as A, B, and C, and the converter devices A, B, and C are respectively connected to the control processing unit 21 as shown in FIG. And the ATM interface unit 22, the LAN interface unit 23, and the address conversion table 24. The control processing unit 21 in the second embodiment uses the above-described IPv6 address. It has a function to generate. Similarly to the initial state in the case shown in FIG. 5, the internal VPI: 70 corresponding to the external VPI: 100 and the internal VPI: 71 corresponding to the external VPI: 101 are set in the address conversion table of the converter device A. Then, the internal VPI: 70 corresponding to the external VPI: 110 is set in the address conversion table of the converter device B, and the internal VPI: 71 corresponding to the external VPI: 111 is set in the address conversion table of the converter device C. However, a case will be described in which an address conversion table is constructed by setting a state where a MAC address is not set as an initial state.

  In order to perform data communication from the external VPI: 100 to the external VPI: 110, when a cell arrives at the converter device A from the ATM network of the external VPI: 100, the converter device A refers to the address conversion table 24. Then, the internal VPI: 70 corresponding to the external VPI: 100 is obtained, and as shown in FIG. 8B, the internal VPI: 70 is set in the site topology of the network unit, and the interface ID is all “1” ( A VPI-MAC resolution frame (Request) for which (broadcast) is set is transmitted to the LAN.

  The converter devices B and C that have received the VPI-MAC resolution frame (Request) to which IPv6 is applied compare the network unit including the internal VPI of the own device with the network unit of the received frame. In this case, since it is the same for the network unit including the internal VPI: 70 set in the address conversion table 24 of the converter device B, the VPI-MAC resolution frame (including the MAC address of the own device: BBBBB and applying IPv6 ( (Reply) is transmitted to the converter device A. Further, the converter device C makes no response because the internal VPI is not the same.

By receiving the VPI-MAC resolution frame (Request) from the converter device B, the converter device A sets the MAC address: BBBBB corresponding to the internal VPI: 70 of the address conversion table 24. Further, the converter device B sets the MAC address: AAAAA corresponding to the internal VPI: 70 of the address conversion table 24. Thereby, VPI: 100 in the cell header is changed from the converter device A to the internal VPI: 70, and a frame to which the MAC address: BBBBBB is added is transmitted to the LAN. The converter device B receives the frame of the MAC address: BBBBB, deletes it, changes the VPI of the header of the cell to the external VPI: 110 with reference to the address conversion table 24, and sends it to the ATM network. Send. The processing steps in the above converter devices A and B are substantially the same as those shown in FIGS. 6A and 6B.
As described above, according to the second embodiment, the destination address of the frame transmitted / received between the converter devices is mapped in advance in the IPv6 address space, so that the ATM network and the IPv6 network coexist on the LAN. In addition, it is possible to construct a network system to which the present invention is applied.

  FIG. 9 shows a flowchart of Embodiment 3 of the present invention, where converter devices 2-1 to 2-3 shown in FIG. 1 are denoted as A, B, and C, and each converter device A, B, and C is shown in FIG. As shown, the control processing unit 21, the ATM interface unit 22, the LAN interface unit 23, and the address conversion table 24 are included. The control processing unit 21 in the third embodiment is a VPI. -It has a function of broadcasting a MAC resolution frame (Request) every predetermined period. The function in this case can be provided in all the converter devices, and in that case, it is desirable to make the transmission cycle or the transmission timing different from each other. It can also be provided only in important converter devices.

  Similarly to the initial state in FIG. 5, the internal VPI: 70 corresponding to the external VPI: 100 and the internal VPI: 71 corresponding to the external VPI: 101 are set in the address conversion table of the converter device A. The internal VPI: 70 corresponding to the external VPI: 110 is set in the address conversion table of the converter device B, and the internal VPI: 71 corresponding to the external VPI: 111 is set in the address conversion table of the converter device C. However, from the initial state in which the MAC address is not set, the converter device B periodically transmits the MAC address: BBBBB of its own device and a VPI-MAC resolution frame in which, for example, 70 of the internal VPI is set. Show.

  When the converter device A receives the broadcast VPI-MAC resolution frame from the converter device B, the converter device A refers to the address conversion table 24 based on the internal VPI: 70 set in the VPI-MAC resolution frame, and the internal VPI. : 70 is set, the source MAC address: BBBBB of the VPI-MAC resolution frame is set to support the internal VPI: 70. In this case, since the internal VPI: 70 is not set in the address conversion table 24, the converter device C performs no processing.

  When the external VPI: 100 cell arrives at the converter device A, the external VPI: 100 is converted into the internal VPI: 70 with reference to the address conversion table 24, and a frame with the MAC address: BBBBB added is transmitted. . The converter device B receives the frame of the MAC address: BBBBB addressed to its own device, refers to the address conversion table 24 for the internal VPI: 70, and transmits the cell changed to the external VPI: 110 to the ATM network. That is, communication can be performed between the ATM networks of the external VPI: 100 and the external VPI: 110. Also in the third embodiment, similarly to the second embodiment, a VPI-MAC resolution frame to which IPv6 is applied can be used.

  Further, the converter device C is also provided with a function of periodically broadcasting the VPI-MAC resolution frame, whereby the MAC address: AAAAA of the counterpart converter device A corresponding to the internal VPI: 71 is collected by the response frame, and the address conversion table. 24 can be set. Further, by periodically broadcasting the VPI-MAC resolution frame, the contents of the address translation table 24 can be automatically updated even when the network system is changed including addition and deletion of converter devices.

  FIG. 10 is an explanatory diagram of the main part of the converter device according to the fourth embodiment of the present invention. The same reference numerals as those in FIG. 2 indicate the same name parts, 25 indicates the opposite VPI-MAC table, An address can be set from the processing unit 21 to the opposite VPI-MAC table 25. In addition, (a) to (f) of alternate long and short dash arrows indicate processing steps. FIG. 11 shows a flowchart of the fourth embodiment of the present invention, wherein converter devices 2-1 to 2-3 shown in FIG. 1 are A, B, and C, and converter device A has the configuration shown in FIG. Moreover, the converter apparatuses B and C show the case where it has the structure shown in FIG.

  In FIG. 11, as in the case shown in FIGS. 5 and 9, the address conversion table 24 of the converter device A has an internal VPI: 70 corresponding to the external VPI: 100 and an external in the initial state. The internal VPI: 71 corresponding to the VPI: 101 is set, the internal VPI: 70 corresponding to the external VPI: 110 is set in the address conversion table 24 of the converter apparatus B, and the address conversion table 24 of the converter apparatus C is set. Is the state in which the internal VPI: 71 corresponding to the external VPI: 111 is set, but the counter MAC address is not set, and the counter VPI-MAC table 25 of the converter device A includes the destination MAC address and The external VPI, the internal VPI, and the opposite MAC address are stored in association with each other. In the MAC address and the like it has not been set.

  In the converter device A, as shown in FIG. 11, the MAC addresses BBBBB and CCCCC of the converter devices B and C are registered as counter MAC addresses in the address conversion table 24 by command registration, and the counter VPI- By registering the command to the MAC table 25, the MAC addresses BBBBB and CCCCCC of the converter devices B and C, the external VPI, the internal VPI, and the MAC address AAAAA of the own device as the opposite MAC address are transmitted as the destination MAC addresses. Set. In the processing steps in FIG. 10, the setting control is performed on the address conversion table 24 and the opposite VPI-MAC table 25 from the control processing unit 21 as indicated by the one-dot chain arrows (a) and (b). .

  When the setting registration processing is completed, the control processing unit 21 accesses the counter VPI-MAC table 25 (c), reads the registered content (d), and generates a frame based on the destination MAC address (e). Then, the data is transmitted via the LAN interface unit 23 (f). In this case, it can be transmitted as a VPI-MAC resolution frame including a transmission destination MAC address, a transmission source MAC address, a type (VPI-MAC resolution TYPE), a request type (Reply), and an internal VPI.

  Thereby, the converter device B can receive the frame of the transmission destination MAC address: BBBBB, and can configure the address conversion table 24 in which the external VPI: 110, the internal VPI: 70, and the opposite MAC address: AAAAA are set. Further, the converter device C can receive the frame of the transmission destination MAC address: CCCCC and configure the address conversion table 24 in which the external VPI: 111, the internal VPI: 71, and the opposing MAC address: AAAAA are set.

  Therefore, after that, when the ATM interface unit 22 of the converter apparatus A receives a cell from the ATM network of the external VPI: 100, the control processing unit 21 refers to the address conversion table 24 and determines the VPI of the cell header. The internal VPI is changed to 70, a frame with the opposite MAC address: BBBBB added is generated, and transmitted from the LAN interface unit 23 to the LAN. The converter device B receives this frame by the LAN interface unit 23, removes the MAC address, changes the internal VPI: 70 of the cell header to the external VPI: 110, and converts the cell from the ATM interface unit 22 to the ATM. Send to the network.

  Also, by setting and registering MAC addresses corresponding to the external VPI and internal VPI in the address conversion table 24 of each converter device, a network system in which a plurality of ATM networks are connected via a LAN is constructed. It is also possible to transmit and receive network cells as frames within the LAN. In the LAN, it is also possible to use a frame having the above-described IPv6 address configuration.

It is explanatory drawing of the outline | summary of the network system of Example 1 of this invention. It is principal part explanatory drawing of the converter apparatus of Example 1 of this invention. It is explanatory drawing of VPI and a MAC address. It is explanatory drawing of a VPI-MAC resolution frame. It is a flowchart of Example 1 of this invention. It is explanatory drawing of a process of a converter apparatus. It is a flowchart of Example 2 of this invention. It is explanatory drawing of an IPv6 address. It is a flowchart of Example 3 of the present invention. It is principal part explanatory drawing of the converter apparatus of Example 4 of this invention. It is a flowchart of Example 4 of the present invention.

Explanation of symbols

1-1 to 1-3 ATM switch 2, 2-1 to 2-3 Converter device 3 LAN
21 Control processing unit (CPU)
22 ATM interface (ATMIF)
23 LAN interface unit (LANIF)
24 Address conversion table

Claims (1)

A plurality of first communication networks having the same communication protocol and a communication device installed between the first communication network and a second communication network having a different communication protocol,
An address conversion table for storing a destination identifier used in the first communication network and a device identifier for identifying a data destination device connected to the second communication network;
When data is received from the first communication network, destination information corresponding to a destination identifier included in the data and a device identifier for identifying a data transmission source device connected to the first communication network are Means for casting on the communication network of
Receiving means for receiving destination information corresponding to the destination identifier and a device identifier for identifying the data transmission source device from the second communication network;
Storage means for storing the device identifier received by the receiving means in the address conversion table in association with a destination identifier used in the first communication network and the destination information ;
A communication device characterized in that is provided.

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