Communication system, program, and communication method

Abstract

To provide a communication system, a program and a communication method, capable of reducing a load of management of a communication device by a management device, in a system for managing a plurality of communication devices by the management device.SOLUTION: A communication system 100 includes a plurality of network devices 6, an aggregation device 2, and a management device 1 for managing communication of the plurality of network devices 6, and the aggregation device 2 acquires connection part information of the network devices 6 from all the network devices 6 and aggregates connection parts 60 of all the network devices 6 into one or a plurality of virtual devices based on the connection part information. Aggregated information in which a connection part number of a network device 6 is assigned to each connection part of a virtual device is generated, the aggregated information is transmitted to a management device 1, the number of virtual devices is smaller than the number of actually connected network devices 6, and the management device 1 manages all the network devices 6 connected to an aggregation device 2 on the basis of the aggregated information.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present invention relates to a communication system, a program, and a communication method. [Background technology]

[0002] Conventionally, there is known a technology in which a higher-level management device manages a plurality of communication devices in a communication network configured by the plurality of communication devices. Patent Document 1 describes a system that includes a centralized management server that manages the allocation of one or more managed devices to one or more data processing execution servers, and a management tool that increases or decreases the number of data processing execution servers, and that reallocates the managed devices and updates their connection destination settings based on the increase or decrease in the number of data processing execution servers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-154659 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the management device needs to manage the IP addresses and the like of each network device, and as the number of communication devices increases, the management burden increases. Patent Document 1 describes increasing or decreasing the number of data processing execution servers connected to the centralized management server, but does not describe how to deal with a situation in which the number of connected communication devices increases.

[0005] The present invention aims to provide a communication system, a program, and a communication method that can reduce the burden of managing communication devices on a management device in a system in which a plurality of communication devices are managed by the management device. [Means for solving the problem]

[0006] (1) A communication system includes a plurality of network devices, an aggregation device to which the plurality of network devices are connected, and a management device capable of communicating with the plurality of network devices via the aggregation device and managing the communications of the plurality of network devices, wherein the aggregation device performs a startup status confirmation process with all connected network devices to obtain connection information of the network devices, aggregates the connections of all network devices into one or more virtual devices based on the connection information, generates aggregated information in which the connection number of the network device is assigned to each connection of the virtual devices, and transmits the generated aggregated information to the management device, wherein the number of virtual devices is fewer than the number of the network devices actually connected, and the management device manages all network devices connected to the aggregation device based on the aggregated information.

[0007] (2) In the communication system described in (1), the management device refers to the aggregation information and sends a management message to the connection number of the virtual device, and when the aggregation device receives the management message, it identifies the connection number of the network device that corresponds to the connection number of the virtual device and sends the management message to the connection number of the identified network device.

[0008] (3) In the communication system described in (2), when the aggregation device receives a response from the network device, it identifies the connection number of the virtual device corresponding to the connection number of the network device and sends a message to the management device indicating that a response has been received from the identified connection number.

[0009] (4) In a communication system described in any one of (1) to (3), when a request is made to add a new network device, the aggregation device performs a process of confirming the startup status with the new network device to obtain connection information held by the network device, assigns a connection number based on the connection information to an available connection number of the virtual device, updates the aggregation information, and sends the updated aggregation information to the management device to request the addition.

[0010] (5) In a communication system described in any one of (1) to (3), when a request for deletion of a network device is received, the aggregation device updates the aggregation information by removing the connection number based on the connection information held by the network device from the connection number of the virtual device, and sends the updated aggregation information to the management device to request deletion.

[0011] (6) In the communication system described in (1), the aggregation device assigns each connection part on the network device side to each connection part of the virtual device, assigns a port number on the network device side to each connection part on the network device side to generate the aggregation information, and transmits the aggregation information to the management device, and the aggregation device has an address conversion means and a routing means based on the aggregation information.

[0012] (7) In the communication system described in (6), when there is a request to add a new network device, the aggregation device assigns a connection number based on the connection information of the newly added network device to an available connection number of the virtual device, assigns a port number on the network device side to the connection of the added network device, updates the aggregation information by associating the connection number of the virtual device with the connection number of the new network device, and sends the updated aggregation information to the management device to request the addition.

[0013] (8) In the communication system described in (6) or (7), when a request is made to delete a network device, the aggregation device removes the identification information of the network device to be deleted and the connection number of each connection part of the network device from the connection number of the virtual device, updates the aggregation information so that the connection number of the virtual device corresponds to the port number on the management device side, and sends the updated aggregation information to the management device to request deletion.

[0014] (9) The program is executed by a computer of a communication system including a plurality of network devices, an aggregation device to which the plurality of network devices are connected, and a management device capable of communicating with the plurality of network devices via the aggregation device and managing the communications of the plurality of network devices, and includes the steps of controlling the aggregation device to perform a startup status confirmation process between the aggregation device and all connected network devices to obtain connection information of the network devices, and aggregating the connections of all network devices into one or more virtual devices based on the connection information, generating aggregation information in which the connection number of the network device is assigned to each connection of the virtual devices, transmitting the aggregation information to the management device, and managing all network devices connected to the aggregation device by the management device based on the aggregation information, wherein the number of the virtual devices is smaller than the number of the network devices actually connected.

[0015] (10) A communication method is applied to a communication system including a plurality of network devices, an aggregation device to which the plurality of network devices are connected, and a management device capable of communicating with the plurality of network devices via the aggregation device and managing communication of the plurality of network devices, the communication method including the steps of: controlling the aggregation device to perform a startup status confirmation process with all connected network devices to obtain connection information of the network devices; aggregating the connections of all network devices into one or more virtual devices based on the connection information; generating aggregated information in which the connection number of the network device is assigned to each connection of the virtual devices; transmitting the aggregated information to the management device; and managing all network devices connected to the aggregation device by the management device based on the aggregated information, wherein the number of the virtual devices is smaller than the number of the network devices actually connected. [Effects of the Invention]

[0016] According to the present invention, in a system in which a management device manages a plurality of communication devices, the burden of managing the communication devices on the management device can be reduced. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing a communication system according to a first embodiment. [Figure 2] 2 is a block diagram showing the hardware configuration of a management device according to the first embodiment. FIG. [Figure 3] 2 is a block diagram showing the hardware configuration of the aggregation device according to the first embodiment. FIG. [Figure 4] 1 is a block diagram showing the hardware configuration of a network switch according to a first embodiment. [Figure 5] 2 is a block diagram showing a hardware configuration of a carrier-side communication device according to the first embodiment; FIG. [Figure 6] 1 is a schematic diagram illustrating an example of a center device including a management device and a plurality of carrier-side communication devices in a communication system according to a first embodiment. [Figure 7] 3 is a schematic diagram showing an example of data exchange between a management device and an OLT via an aggregation device in the communication system according to the first embodiment. FIG. [Figure 8] 2 is a block diagram showing the configuration of functional blocks of an aggregation device according to the first embodiment; FIG. [Figure 9] 2 is a block diagram showing the configuration of functional blocks of a management device according to the first embodiment; FIG. [Figure 10] 4 is a diagram showing an example of a conversion table used by the aggregation device to convert between a connection number of a virtual OLT and a connection number of a real OLT in the first embodiment; FIG. [Figure 11] 10 is a diagram showing an example of the identification information and connection unit number of a virtual OLT indicated by the aggregation information acquired by the management device in the first embodiment. FIG. [Figure 12]4 is a sequence diagram showing an example of a processing flow from registration of device information by a management device to transmission and reception of messages between the management device and a network device in the communication system according to the first embodiment. FIG. [Figure 13] 10 is a sequence diagram showing an example of the flow of a process in which the management device in the communication system according to the first embodiment registers device information relating to a new network device. FIG. [Figure 14] 10 is a flowchart showing an example of the flow of processing up to transmission of aggregated information to a management device in the aggregation management processing executed by the aggregation device according to the first embodiment. [Figure 15] 10 is a flowchart showing an example of the flow of processing up to registration of a virtual device in the centralized management processing executed by the management device according to the first embodiment. [Figure 16] 10 is a flowchart showing an example of the processing flow when a management message is sent from a management device to a network device in the centralized management processing of the first embodiment. [Figure 17] 10 is a flowchart showing an example of the processing flow when a response message is sent from a network device to a management device in the centralized management processing of the first embodiment. [Figure 18] 10 is a flowchart showing an example of the flow of processing for updating aggregation information in the aggregation management processing executed by the aggregation device according to the first embodiment. [Figure 19] FIG. 10 is a schematic diagram showing an example of data exchange between a management device and an OLT via an aggregation device in a communication system according to a second embodiment. [Figure 20] FIG. 10 is a block diagram showing the configuration of functional blocks of an aggregation device according to a second embodiment. [Figure 21] FIG. 10 is a block diagram showing the configuration of functional blocks of a management device according to a second embodiment. [Figure 22] FIG. 11 is a diagram illustrating an example of a communication path table in the second embodiment. [Figure 23] FIG. 11 is a diagram illustrating an example of a table that associates connection unit numbers of virtual devices with connection unit numbers of aggregation devices in the second embodiment. [Figure 24] FIG. 11 is a sequence diagram showing an example of a processing flow from registration of device information by a management device to transmission and reception of messages between the management device and an OLT in a communication system according to the second embodiment. [Figure 25] FIG. 11 is a sequence diagram showing an example of a processing flow from registration of information about a new OLT by a management device in a communication system according to the second embodiment to transmission and reception of a message with the newly registered OLT. [Figure 26] 10 is a flowchart showing an example of the flow of processing up to transmission of aggregated information to a management device in the aggregation management processing executed by an aggregation device according to the second embodiment. [Figure 27] 10 is a flowchart showing an example of the flow up to the registration of information about network devices in the centralized management process executed by the management device according to the second embodiment. [Figure 28] 10 is a flowchart showing an example of the flow of processing when a management message is sent from a management device to a network device in the centralized management processing of the second embodiment. [Figure 29] 10 is a flowchart showing an example of the flow of processing for updating aggregation information in aggregation management processing executed by an aggregation device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] First Embodiment A communication system 100 according to a first embodiment of the present invention will be described below. FIG.

[0019] The communication system 100 according to this embodiment is a system that provides various communication services to subscribers.

[0020] The communication system 100 includes a management device 1, an aggregation device 2, a plurality of network devices 6, and a subscriber-side communication device 5 connected to the network device 6. Examples of the network device 6 include a network switch 3 and a carrier-side communication device 4. In this specification, a subscriber is a user who uses a communication service provided by the communication system 100 according to this embodiment.

[0021] The management device 1 is connected to a plurality of network devices 6 via an aggregation device 2. The management device 1 controls and manages communications in a communication network NW that is made up of the plurality of network devices 6, subscriber-side communication devices 5 connected thereto, and the like.

[0022] The aggregation device 2 is connected to a plurality of network devices 6. In this embodiment, the aggregation device 2 is connected to the management device 1 via a communication line P1, and is connected to a plurality of network switches 3 via a communication line P2, or to a plurality of carrier-side communication devices 4 via a communication line P3. The communication lines P1, P2, and P3 may be wireless lines or wired lines. If they are wired lines, they may be configured, for example, by a communication cable that transmits electrical signals.

[0023] 1, a communication system 100 of this embodiment includes a plurality of aggregation devices 2. A plurality of network switches 3 or OLTs 4 are connected to one aggregation device 2. That is, the same type of network devices 6 are connected to one aggregation device 2. The management device 1 and the aggregation devices 2 will be described in detail later.

[0024] The network switch 3 interconnects the management device 1 and multiple subscriber-side communication devices 5 connected to the network switch 3 via the aggregation device 2. The network switch 3 has multiple connection units 9. The connection units 9 include a connection unit 91 for connecting to an upstream device and a connection unit 92 for connecting to a downstream device. The network switch 3 has multiple connection units 91 and multiple connection units 92. The network switch 3 is connected to the aggregation device 2 via a communication line P2 connected to the connection unit 91. Examples of the network switch 3 include an L2 switch and an L3 switch.

[0025] The communication system 100 of this embodiment includes, for example, two network switches 3. Each of the two network switches 3 includes, for example, 16 connection units 92 for connecting to communication devices. Note that some of the connection units 91 and 92 included in the network switch 3 are omitted in FIG. 1.

[0026] The carrier-side communication device 4 is a communication device installed in the central office of a communication carrier that provides communication services. The carrier-side communication device 4 is, for example, an OLT (optical line terminal) that serves as an optical line termination device that communicates using optical signals. In the following explanation, the carrier-side communication device 4 will be referred to as OLT4. The OLT4 is connected to the aggregation device 2 via a communication line P3, and is connected to a plurality of ONUs 51 that serve as a plurality of subscriber-side communication devices 5 via a communication line P4 and an optical splitter (not shown). The communication line P4 is, for example, an optical line configured by an optical fiber cable.

[0027] The OLT 4 interconnects the management device 1 and the subscriber-side communication devices 5 connected to the OLT 4 via the aggregation device 2. The OLT 4 has a plurality of connection units 7. The connection units 7 include a plurality of connection units 71 for connecting to upstream devices and a plurality of connection units 72 for connecting to downstream devices. The OLT 4 is connected to the aggregation device 2 via a communication line P3 connected to the connection units 71, and is connected to the subscriber-side communication devices 5 via a communication line P4 connected to the connection units 72.

[0028] The communication system 100 of this embodiment includes, for example, two OLTs 4. Each of the two OLTs 4 has, for example, four connection units 72 for connecting to a plurality of subscriber-side communication devices 5. In the following description, the connection units 72 of the OLTs 4 and the connection unit 92 of the network switch 3 will be collectively referred to as the "connection unit 60."

[0029] The subscriber-side communication device 5 is installed at the premises of a subscriber who receives communication services, and is managed by the management device 1 and network device 6. The subscriber-side communication device 5 is connected to network devices 6 such as a network switch 3 and an OLT 4. Examples of the subscriber-side communication device 5 include an ONU (optical network unit) 51, an L2 switch (not shown), a modem (not shown) that modulates and demodulates signals, and a router (not shown). The ONU 51 is an optical line termination device connected to the OLT 4, communicates with the OLT 4 via optical signals, and converts received optical signals into electrical signals. The ONU 51 is connected to, for example, customer-premises equipment (CPE, not shown), which is communication equipment installed on the premises of a subscriber. Examples of the CPE include a router.

[0030] Next, a description will be given of the hardware configuration of each device that constitutes the communication system 100. Fig. 2 is a block diagram showing the hardware configuration of the management device 1.

[0031] The management device 1 includes a computer 16, a storage unit 13, and an I / F unit 14. A bus 15 and the like connect these units together.

[0032] The computer 16 includes a processor 10 and a read-only memory (ROM) 11 and a random-access memory (RAM) 12 as main storage devices. The processor 10 may be a central processing unit (CPU), a microprocessing unit (MPU), a system on a chip (SoC), a digital signal processor (DSP), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). Alternatively, the processor 10 may be a combination of these. The processor 10 may also be a combination of these with a hardware accelerator or the like. The processor 10 controls each component to implement various functions of the management device 1 based on programs such as firmware, system software, and application software stored in the ROM 11, the RAM 12, or an auxiliary storage device that is part of the storage unit 13. Note that some or all of these programs may be incorporated into the circuitry of the processor 10.

[0033] The storage unit 13 is a storage area for various programs and various data for causing the hardware group to function as the management device 1, and can be configured with a ROM, RAM, flash memory, a solid-state drive (SSD), a hard disk drive (HDD), etc. Specifically, the storage unit 13 stores programs for causing the computer 16 to execute each function of this embodiment, communication setting information including route information for data transfer processing by each communication device constituting the communication network NW, aggregation information, etc. The communication setting information and aggregation information will be described later.

[0034] The I / F unit 14 is a communication interface that enables the management device 1 to communicate with various communication devices in the communication network NW, such as the aggregation device 2, network switch 3, OLT 4, and subscriber-side communication device 5, as well as with a server (not shown) that manages the management device 1 and other external devices.

[0035] The following describes the hardware configuration of the aggregation device 2. FIG.

[0036] The aggregation device 2 includes a computer 26, a storage unit 23, and an I / F unit 24. A bus 25 and the like connect these units together.

[0037] The computer 26 includes a processor 20 and a read-only memory (ROM) 21 and a random-access memory (RAM) 22 as main storage devices. The processor 20 may be a central processing unit (CPU), a microprocessing unit (MPU), a system on a chip (SoC), a digital signal processor (DSP), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). Alternatively, the processor 20 may be a combination of these. The processor 20 may also be a combination of these with a hardware accelerator. The processor 20 controls each component to realize various functions of the aggregation device 2 based on programs such as firmware, system software, and application software stored in the ROM 21, the RAM 22, or an auxiliary storage device that is part of the storage unit 23. Note that some or all of the programs may be incorporated into the circuitry of the processor 20.

[0038] The storage unit 23 is a storage area for various programs and various data for causing the hardware group to function as the aggregation device 2, and can be configured with a ROM, RAM, flash memory, a solid-state drive (SSD), a hard disk drive (HDD), etc. Specifically, the storage unit 23 stores programs for causing the computer 26 to execute each function of this embodiment, communication setting information including path information for data transfer processing such as a routing table and a MAC address table, aggregation information, etc.

[0039] The I / F unit 24 is a communication interface for the aggregation device 2 to communicate with various communication devices such as the management device 1, the network switch 3, the OLT 4, and the subscriber-side communication device 5.

[0040] The following describes the hardware configuration of the network switch 3. FIG.

[0041] The network switch 3 includes a computer 36, a storage unit 33, and an I / F unit 34. A bus 35 and the like connect these units together.

[0042] The computer 36 includes a processor 30 and a read-only memory (ROM) 31 and a random-access memory (RAM) 32 as main storage devices. The processor 30 may be a central processing unit (CPU), a microprocessing unit (MPU), a system on a chip (SoC), a digital signal processor (DSP), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). Alternatively, the processor 30 may be a combination of these. The processor 30 may also be a combination of these with a hardware accelerator or the like. The processor 30 controls each component to realize various functions of the network switch 3 based on programs such as firmware, system software, and application software stored in the ROM 31, the RAM 32, or an auxiliary storage device that is part of the storage unit 33. Note that some or all of these programs may be incorporated into the circuitry of the processor 30.

[0043] The storage unit 33 is a storage area for various programs and various data for causing the hardware group to function as the network switch 3, and can be configured with a ROM, RAM, flash memory, a solid-state drive (SSD), a hard disk drive (HDD), etc. Specifically, the storage unit 33 stores programs for causing the computer 36 to execute each function of this embodiment, communication setting information including route information for data transfer processing such as a routing table and a MAC address table, etc.

[0044] The I / F unit 34 is a communication interface for the network switch 3 to communicate with various communication devices such as the management device 1 and the aggregation device 2.

[0045] The hardware configuration of the OLT 4 will now be described with reference to Figure 5, which is a block diagram showing the hardware configuration of the OLT 4.

[0046] The OLT 4 includes a computer 46, a storage unit 43, and an I / F unit 44. A bus 45 and the like connect these units together.

[0047] The computer 46 includes a processor 40 and a read-only memory (ROM) 41 and a random-access memory (RAM) 42 as main storage devices. The processor 40 may be a central processing unit (CPU), a microprocessing unit (MPU), a system on a chip (SoC), a digital signal processor (DSP), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). Alternatively, the processor 40 may be a combination of these. The processor 40 may also be a combination of these with a hardware accelerator or the like. The processor 40 controls each component to realize various functions of the OLT 4 based on programs such as firmware, system software, and application software stored in the ROM 41, the RAM 42, or an auxiliary storage device that is part of the storage unit 43. Note that some or all of the programs may be incorporated into the circuitry of the processor 40.

[0048] The storage unit 43 is a storage area for various programs for causing the hardware group to function as the OLT 4, various data, etc., and can be configured with a ROM, RAM, flash memory, a solid-state drive (SSD), a hard disk drive (HDD), etc. Specifically, the storage unit 43 stores programs for causing the computer 46 to execute each function of this embodiment, identification information of the connected ONUs 51, communication setting information including route information, etc.

[0049] The I / F unit 44 is a communication interface for the OLT 4 to communicate with the aggregation device 2, the network switch 3, the ONU 51, and the like.

[0050] The management device 1 in the communication system 100 of this embodiment functions as an SDN controller. That is, the management device 1 performs communication settings between a plurality of network switches 3, a plurality of OLTs 4, and a plurality of subscriber-side communication devices 5 that exist within the communication network NW, and executes control plane control that manages communication in the communication network NW.

[0051] Control plane control refers to the creation of communication setting information, including route information for data transfer processing performed by each communication device in the network, and the control of managing the communication operations of each communication device. For example, in this embodiment, the network switch 3, OLT 4, subscriber-side communication device 5, etc. perform transfer processing of received data, and the management device 1 creates communication setting information for data transfer processing by the network switch 3, OLT 4, subscriber-side communication device 5, etc. In other words, as shown in Fig. 1, the communication network NW becomes a virtual network managed collectively by the management device 1. This eliminates the need to individually configure each communication device in the communication network NW, making it easier to manage the entire communication system 100.

[0052] Control plane control is mainly realized by the processor 10. The control plane control is executed based on a control protocol such as OpenFlow or NETCONF. The storage unit 13, the ROM 11, or the like stores software that enables the management device 1 to function as an SDN controller. The storage unit 13, the ROM 11, or the like also stores connection information for each network switch 3, OLT 4, subscriber-side communication device 5, and the like in the communication system 100.

[0053] Here, in control plane control, the management device 1 collectively registers and manages the communication devices included in the communication network NW, so as the number of communication devices in the communication network NW increases, the burden on the management device 1 increases and management may become complicated.

[0054] FIG. 6 is a schematic diagram showing an example of a center device 8 including one management device 1 and multiple OLTs 4. The center device 8 allows card-type OLTs 4 to be inserted into a housing 81 provided in a housing 80. In the center device 8 shown in FIG. 6, up to 12 OLTs 4 can be inserted independently. Also, as shown in FIG. 6, one OLT 4 has four connection units 72. Up to 128 ONUs 51 can be connected to one connection unit 72 of the OLT 4 via a communication line P4 and an optical splitter.

[0055] If 12 OLTs 4 are inserted into the center device 8, the management device 1 will communicate with each of the 12 OLTs 4 individually, register each in the database, and perform management control. Therefore, as the number of OLTs 4 increases, mapping and display processing will be performed for each OLT 4, increasing the processing load on the management device 1. Furthermore, since each OLT 4 may be connected to a large number of ONUs 51, processing such as mapping for each OLT 4 becomes complicated, making management cumbersome.

[0056] In the communication system 100 according to this embodiment, the aggregation device 2 transmits information to the management device 1 regarding multiple network devices 6 of the same type connected to it as being realized by a number of virtual devices that is fewer than the actual number, and the management device 1 performs aggregation management processing to manage the multiple network devices 6 based on that information. For example, the aggregation device 2 transmits to the management device 1 that 12 OLTs 4 arranged in the center device 8 are a virtual device aggregated into one OLT 4. As a result, from the perspective of the management device 1, the 12 OLTs 4 that actually exist are recognized as a single aggregated OLT 4, so that the number of devices that need to be individually registered and managed can be reduced, making management easier.

[0057] Next, the functional configuration of the management device 1 and aggregation device 2 in the centralized management process will be described using the communication system 100 shown in Figure 7 as an example. Figure 7 is a diagram showing the communication system 100 including one aggregation device 2 and three OLTs 4 connected to the aggregation device 2, and is a schematic diagram showing an example of data exchange between the management device 1 and the OLTs 4 via the aggregation device 2. Figure 8 is a block diagram showing the configuration of the functional blocks of the aggregation device 2 in the centralized management process. Figure 9 is a block diagram showing the configuration of the functional blocks of the management device 1 in the centralized management process. Note that the dashed-dotted arrows in Figure 7 indicate an example of the direction in which centralized information, described later, is transmitted, and the dashed arrows indicate an example of the direction in which messages are transmitted.

[0058] The functional configuration of aggregation device 2 for performing aggregation management processing will be described. The aggregation management processing by aggregation device 2 is mainly realized by processor 20. As shown in FIG. 8 , processor 20 includes a confirmation processing unit 201, an aggregation information generation unit 202, an aggregation information update unit 204, and a transfer processing unit 203.

[0059] The confirmation processor 201 executes a process (hereinafter referred to as a startup status confirmation process) for confirming the startup status of the network devices 6 actually connected to the aggregation device 2. Specifically, the confirmation processor 201 acquires device information about the network devices 6 connected to the aggregation device 2 and in operation. The device information may include, for example, identification information about each network device 6, connection unit information about the connection units 60, such as the connection unit 72 and the connection unit 92, that each network device 6 has, and the number of network devices 6 connected to one aggregation device 2. The connection unit information may include, for example, the number of operable connection units 60 that one network device 6 has, the connection unit numbers of each operable connection unit 60, and the number of network devices 6 connected to one aggregation device 2. The identification information of the network devices 6 is not particularly limited and may be, for example, an IP address or a MAC address. In this embodiment, the confirmation processor 201 starts the startup status confirmation process when it receives a device registration signal from the management device 1.

[0060] The aggregated information generation unit 202 generates aggregated information based on the device information acquired by the confirmation processing unit 201, and executes a process of transmitting the generated aggregated information to the management device 1. The aggregated information is information in which the connection units 60 of each network device 6 are assigned to the connection units of a smaller number of virtual devices than all of the network devices 6 actually connected to the aggregation device 2. The aggregated information may include, for example, identification information of the virtual devices, connection unit information of the connection units of the virtual devices, etc. The identification information of the virtual devices is not particularly limited, and may be, for example, an IP address or a MAC address.

[0061] The aggregated information generating unit 202 may generate aggregated information by performing the following processes (A) and (B), for example. (A) Based on the connection information acquired by the confirmation processing unit 201, the connections 60 of all the network devices 6 connected to the aggregation device 2 are aggregated into one or more virtual devices. (B) Generate aggregated information in which the connection number of the network device 6 is assigned to each connection of the virtual device.

[0062] In the above (B), a number of virtual devices is set that is less than the number of network devices 6 of the same type actually connected to the aggregation device 2, and the connections 60 of all of the network devices 6 are aggregated into the set virtual devices. The number of set virtual devices is not particularly limited as long as it is less than the number of network devices 6 of the same type (hereinafter referred to as real network devices 6) actually connected to the aggregation device 2. In other words, the aggregation information is not particularly limited as long as it is information that results in a number of virtual devices that is less than the number of real network devices 6 of the same type actually connected to the aggregation device 2. For example, the aggregation information generation unit 202 may aggregate the connections 60 of two or more real network devices 6 into one virtual device in the above (A) and assign connection numbers of the network devices 6 to the connections of the one virtual device. In other words, the aggregation information generation unit 202 may generate aggregation information that virtualizes two or more real network devices 6 into a single virtual device that has all of the connections 60 of the two or more real network devices 6.

[0063] Furthermore, for example, the aggregated information generator 202 may aggregate the connections 60 of three or more real network devices 6 in (A) above into two or more virtual devices that are fewer than the number of real network devices 6, and assign the connections 60 to each of the two or more virtual devices. In this case, the aggregated information generator 202 may generate aggregated information in which the connections 60 of one real network device 6 are allocated to the same virtual device, or may generate aggregated information in which the connections 60 are allocated to two different virtual devices. For example, when the connections 60 of three real network devices 6 are aggregated into two virtual devices, two of the three real network devices 6 may be aggregated into one virtual device and the remaining real network device 6 may be the other virtual device. Alternatively, one of the three real network devices 6 may be allocated to one virtual device, the second to the other virtual device, and the connection 60 of the third real network device 6 may be allocated to the two virtual devices. Alternatively, for example, the multiple connections 60 that each of the three real network devices 6 has may be distributed to two virtual devices.

[0064] Fig. 10 is a diagram showing an example of a conversion table showing the relationship between an OLT4 (hereinafter referred to as a real OLT4) which is a real network device 6 and an OLT4 (hereinafter referred to as a virtual OLT4) which is a virtual device converted from the real OLT4. The conversion table shown in Fig. 10 shows identification information of each real OLT4 and connection number which is the connection number of each connection unit 72 that the real OLT4 has, as well as identification information of a virtual OLT4 and connection number of each connection unit 72 that the virtual OLT4 has.

[0065] In Fig. 10, three real OLTs 4, each with identification information "A," "B," and "C," are aggregated into one virtual OLT 4 with identification information "V." In the following explanation, the OLT 4 with identification information "A" may be referred to as "OLT4A," the OLT 4 with identification information "B" as "OLT4B," the OLT 4 with identification information "C" as "OLT4C," and the OLT 4 with identification information "V" as "OLT4V."

[0066] 10, each of OLT4A to OLT4C has four connection units 72. In the example shown in Fig. 10, the aggregation information generation unit 202 aggregates OLT4A to OLT4C into OLT4V having 12 connection units 72 with connection unit numbers 1 to 12.

[0067] The aggregated information generation unit 202 transmits the generated aggregated information to the management device 1, as indicated by the two-dot chain arrow in Fig. 7. Fig. 11 is an example of a table showing the identification information of the virtualized OLT 4 indicated in the aggregated information transmitted to the management device 1 by the aggregated information generation unit 202 and the connection unit numbers of the connections 72 that the virtualized OLT 4 has. The management device 1 recognizes, registers, and manages three real OLTs 4 as one virtual OLT 4 having 12 connection units 72.

[0068] When there is a request to add a new network device 6, the aggregation information update unit 204 executes a process to update the aggregation information to include information about the new network device 6. For example, when the aggregation information update unit 204 receives a request to add a new network device 6, it causes the confirmation processing unit 201 to execute a startup status confirmation process and acquire device information including connection information about the newly added network device 6. The aggregation information update unit 204 updates the aggregation information by assigning a connection number based on the connection information of the newly added network device 6 to an available connection number of the virtual device. Then, the aggregation information update unit 204 transmits the updated aggregation information to the management device 1 to request the addition.

[0069] Furthermore, when there is a request to delete a network device 6 that is under management by management device 1, aggregated information update unit 204 executes a process of updating the aggregated information to information that removes information related to the network device 6 to be deleted. For example, when the aggregated information update unit 204 receives a request to delete a network device 6, it updates the aggregated information by removing the identification information of the network device 6 to be deleted and the connection number of each connection 60 that the network device 6 has from the connection number of the virtual device. Then, aggregated information update unit 204 transmits the updated aggregated information to management device 1 to request deletion.

[0070] The transfer processing unit 203 executes a process for transferring data exchanged between the management device 1 and the network device 6 to the correct destination.

[0071] For example, when the transfer processing unit 203 receives a management message addressed to the OLT 4 from the management device 1, it refers to the conversion table and identifies the identification information of the real OLT 4 and the connection number of its connection 72 that correspond to the identification information of the virtual OLT 4 that is the destination of the management message and the connection number of its connection 72. For example, when the transfer processing unit 203 receives a message sent from the management device 1 and addressed to connection number 1 of OLT4V, it refers to the conversion table and identifies that the real destination of the management message is connection 72 with connection number A1 of OLT4A. Then, the transfer processing unit 203 transmits the management message to the identified connection 72 of connection number A1 of OLT4A, as shown in FIG. 7.

[0072] On the other hand, when the transfer processing unit 203 receives a response message addressed to the management device 1 from the OLT 4, for example, it refers to the conversion table and identifies the identification information of the real OLT 4, which is the real destination of the response message, and the connection number of the virtual OLT 4 corresponding to the connection number of its connection 72. Next, the transfer processing unit 203 transmits to the management device 1 a message indicating that a response has been received from the identified connection number of the network device 6. For example, the transfer processing unit 203 rewrites the source information added to the header of the response message from the information of the real OLT 4 to the information of the corresponding virtual OLT 4. Then, the transfer processing unit 203 transfers the response message, in which the source information added to the header has been rewritten to the information of the virtual OLT 4, to the management device 1. As a result, the management device 1 receives the response message sent from the real OLT 4 as a response message sent from the virtual OLT 4.

[0073] Next, the functional configuration of management device 1 for performing the centralized management process will be described. The centralized management process by management device 1 is mainly realized by processor 10. As shown in FIG. 9, processor 10 includes an aggregated information acquisition unit 101 and a communication management unit 102.

[0074] The aggregated information acquisition unit 101 executes a process of acquiring aggregated information generated by the aggregated information generation unit 202 of the aggregation device 2 or updated by the aggregated information update unit 204. In this embodiment, the aggregated information acquisition unit 101 transmits to the aggregation device 2 a device registration signal that causes the aggregation device 2 to start acquiring device information, thereby causing the aggregation device 2 to acquire device information and generate aggregated information. Furthermore, when the aggregation information acquisition unit 101 receives from the aggregation device 2 an application for addition or deletion of a network device 6, it acquires the updated aggregated information from the aggregation device 2.

[0075] The communication management unit 102 executes a process of managing information about each communication device included in the communication network NW, such as the network switch 3, the OLT 4, and the ONU 51. The information about each communication device includes, for example, identification information such as the IP address or MAC address of each communication device, the number of connections 60, the connection number of each connection 60, communication setting information, etc.

[0076] For example, the communication management unit 102 associates the communication setting information of each communication device included in the communication network NW with identification information of each communication device and stores it in the storage unit 13, and reads it from the storage unit 13 as needed when updating the communication setting information, etc. In this embodiment, the communication management unit 102 registers and manages each network device included in the communication network NW as a virtual device based on the aggregated information acquired by the aggregated information acquisition unit 101. In the example shown in FIG. 7, the management device 1 registers and manages three real OLTs 4A, 4B, and 4C, each having four connection units 72, as one virtual OLT 4V having 12 connection units 72 as shown in FIG. 11. As a result, instead of registering and managing the three real OLTs 4 individually, they are registered and managed as one virtual OLT 4V, which reduces the number of objects to be managed and simplifies the processing for managing the mapping of the OLTs 4, etc.

[0077] Furthermore, the communication management unit 102 executes a process of transmitting a management message to each communication device included in the communication network NW based on the aggregation information. For example, the communication management unit 102 may set the identification information of a virtual device such as the virtual OLT 4 indicated in the aggregation information and the connection number of the connection unit 72 as the destination and transmit the management message. For example, the communication management unit 102 may send a management message to the aggregation device 2, with the IP address of the virtual OLT 4 indicated in the aggregation information and the connection number of the connection unit 72 added as the destination to the header.

[0078] Next, an example of the process flow for registering device information of network devices 6 in communication system 100 and performing communication between management device 1 and each network device 6 will be described with reference to Fig. 12. Fig. 12 is a sequence diagram showing an example of the process flow from the registration process of network devices 6 to the transmission and reception of data. Fig. 12 explains the process between one management device 1, one aggregation device 2, and two OLTs 4, OLT4A and OLT4B, connected to this aggregation device 2, as an example.

[0079] 12, in step S101, the management device 1 starts registering information about the network devices 6 connected to the aggregation device 2. The management device 1 causes the aggregation device 2 to check the startup status of the multiple network devices 6 connected to the aggregation device 2 and obtain device information about them.

[0080] In step S102, the aggregation device 2 transmits a signal to the OLT 4A to check the activation state of the OLT 4A.

[0081] In step S103, the aggregation device 2 receives device information including its state, identification information, and connection part information from the OLT 4A.

[0082] In step S104, the aggregation device 2 transmits a signal to the OLT 4B to check the activation state of the OLT 4B.

[0083] In step S105, the aggregation device 2 receives device information including its state, identification information, and connection part information from the OLT 4B.

[0084] In step S106, the aggregation device 2 generates aggregated information based on the device information acquired in steps S103 and S105, and transmits the generated aggregated information to the management device 1. At this time, the aggregation device 2 also generates a conversion table that enables the aggregation device to convert between the connection number of the virtual device and the connection number of the actual network device 6. The aggregated information includes identification information and connection information of one virtual OLT 4 having the total number of connection units 72 of OLT4A and OLT4B. In other words, the aggregation device 2 applies for OLT4A and OLT4B as a virtual OLT 4 having the total number of connection units 72 of those OLT4A and OLT4B.

[0085] In step S107, the management device 1 registers information about the virtual OLT 4 as the network device 6 connected to the aggregation device 2 in the storage unit 13 based on the aggregation information.

[0086] In step S108, the management device 1 transmits a management message addressed to the connection 7 of the virtual OLT 4 with the desired connection number.

[0087] In step S109, the aggregation device 2 receives the management message sent in step S108 from the management device 1. Then, the aggregation device 2 compares the connection number of the virtual OLT 4 as the destination attached to the header of the management message with the conversion table generated in step S106, identifies the identification information and connection number of the real OLT 4 as the destination of the message, and transfers the management message to the connection 7 of the identified OLT 4A.

[0088] In step S110, the OLT 4A receives the management message transferred by the aggregation device 2 in step S109, and transmits to the aggregation device 2 a response message addressed to the management device 1 in response to the management message.

[0089] In step S111, the aggregation device 2 receives the response message sent from OLT 4A in step S110. The aggregation device 2 refers to the conversion table generated in step S106 and converts the identification information and connection number of OLT 4A, which are added as the sender in the header of the received response message, into the identification information and connection number of the corresponding virtual OLT 4.

[0090] Next, an example of processing when a new OLT4C is registered in the management device 1 in the communication system 100 shown in Fig. 12 will be described with reference to Fig. 13. Fig. 13 is a sequence diagram showing an example of processing when an OLT4C newly connected to the aggregation device 2 is registered in a state where OLT4A and OLT4B are registered in the management device 1 (step S107). In Fig. 13, OLT4A and OLT4B are registered in the management device 1, and OLT4C is newly connected to the connection unit 27 of the aggregation device 2.

[0091] In step S112, a communication connection is established between the aggregation device 2 and the OLT4C. For example, the aggregation device 2 performs a process of checking the startup status with the OLT4C and acquires connection part information held by the OLT4C. The connection establishment may be initiated by the aggregation device 2, which has received a request to add the OLT4C, sending a connection request to the OLT4C, or by the OLT4C sending a connection request to the aggregation device 2.

[0092] In step S113, the aggregation device 2 receives device information including its state, identification information, and connection part information from the OLT 4C.

[0093] In step S114, the aggregation device 2 updates the existing aggregation information generated in step S106 by adding device information for OLT4C to the existing aggregation information generated in step S106, based on the device information of OLT4C acquired in step S113. At this time, the aggregation device 2 also updates the conversion table for converting between the connection number of the virtual device and the connection number of the actual network device 6. The aggregation information is updated to indicate, for example, a virtual OLT 4 having the number of connections 72 obtained by adding the connections 72 of OLT4C to the connections 72 indicated by the existing virtual OLT 4. In other words, the aggregation device 2 requests the management device 1 to add OLT4A, OLT4B, and OLT4C to be registered as a virtual OLT 4 having the number of connections 72 equal to the total number of connections 72 of those connections 72.

[0094] In step S115, the management device 1 registers information relating to the virtual OLT 4 as the network device 6 connected to the aggregation device 2 based on the aggregation information.

[0095] Next, an example of the aggregation management process executed by the aggregation device 2 according to this embodiment will be described. First, the process up to the point where information about the network device 6 connected to the aggregation device 2 is transmitted to the management device 1 will be described. Fig. 14 is a flowchart showing an example of the flow of the process up to the point where the aggregation information is transmitted to the management device 1 in the aggregation management process executed by the management device 1 and the aggregation device 2.

[0096] As shown in FIG. 14, in step S11, the confirmation processing unit 201 of the aggregation device 2 performs a process of confirming the activation states of the plurality of network devices 6 connected to the aggregation device 2.

[0097] In step S12, the confirmation processing unit 201 acquires device information including connection information of the plurality of network devices 6 that are the targets of the startup state confirmation processing in step S11 and are running.

[0098] In step S13, the aggregation information generation unit 202 aggregates the multiple connections 60 indicated by the connection information of the multiple network devices 6 acquired in step S12 into one or more virtual devices. Specifically, the aggregation information generation unit 202 sets a number of virtual devices that is fewer than the number of network devices 6 connected to the aggregation device 2 indicated by the device information acquired in step S12. Then, the aggregation information generation unit 202 aggregates the connections 60 of all activated network devices 6 indicated by the device information acquired in step S12 into the set virtual device.

[0099] In step S14, the aggregated information generating unit 202 generates aggregated information in which the connection numbers of all active network devices 6 are assigned to each connection of the virtual device set in step S13. At this time, the aggregated information generating unit 202 generates a conversion table for converting between the virtual device and its connection number and the actual network device 6 and its connection number.

[0100] In step S15, the aggregated information generating unit 202 transmits the aggregated information generated in step S12 to the management device 1.

[0101] Next, an example of the aggregation management process executed by the management device 1 according to this embodiment will be described. First, the process up to the point where information about the network device 6 connected to the aggregation device 2 is registered in the management device 1 will be described with reference to Fig. 15. Fig. 15 is a flowchart showing an example of the flow of the process up to the point where aggregation information is registered in the management device 1 in the aggregation management process executed by the management device 1.

[0102] In step S21, the aggregation information acquisition unit 101 of the management device 1 acquires the aggregation information transmitted from the aggregation device 2 in step S15.

[0103] In step S22, the communication management unit 102 of the management device 1 registers the plurality of network devices 6 as virtual devices in the storage unit 13 based on the aggregation information acquired from the aggregation device 2 in step S15.

[0104] Next, a process for transmitting a management message from the management device 1 to the network device 6 when information about the network device 6 has been registered in the management device 1 will be described with reference to Fig. 16. Fig. 16 is a diagram showing an example of a process executed by the management device 1 and the aggregation device 2, in which a message is transmitted from the management device 1 to the OLT 4, which is the network device 6.

[0105] As shown in FIG. 16, in step S31, the communication management unit 102 of the management device 1 refers to the aggregation information registered in step S14, and transmits a management message to a desired connection unit 7 of the virtual OLT 4.

[0106] In step S32, the transfer processing unit 203 of the aggregation device 2 receives the management message sent from the management device 1 in step S31.

[0107] In step S33, the transfer processing unit 203 refers to the conversion table generated in step S15 and identifies the real OLT 4 and its connection number corresponding to the connection number of the virtual OLT that is the destination of the management message received in step S32.

[0108] In step S34, the transfer processing unit 203 transfers the management message received in step S32 to the connection 72 of the connection number of the real OLT 4 identified in step S33. Thereafter, the management message transferred by the aggregation device 2 is received by the OLT 4, and the management message is transmitted to the ONU 51 connected to the connection 72 that received the management message.

[0109] Next, the processing from the OLT 4 that has received a message from the management device 1 in the processing shown in Fig. 16 until it returns a message to the management device 1 via the aggregation device 2 will be described with reference to Fig. 17. Fig. 17 is a flowchart showing an example of the flow of processing executed by the aggregation device 2 until the message sent from the OLT 4 is received by the management device 1.

[0110] As shown in FIG. 17, in step S41, the transfer processing unit 203 of the aggregation device 2 receives a response message addressed to the management device 1 from the OLT 4.

[0111] In step S42, the transfer processing unit 203 identifies the identification information and connection number of the OLT 4 that is the sender of the response message received in step S41.

[0112] In step S43, the transfer processing unit 203 refers to the conversion table generated in step S15, and identifies the identification information and connection number of the virtual OLT 4 that correspond to the identification information and connection number of the source OLT 4 identified in step S42.

[0113] In step S44, the transfer processing unit 203 notifies the management device 1 that a response has been received from the connection number identified in step S43. For example, the transfer processing unit 203 transmits a message to the management device 1, the header of which includes the identification information of the virtual OLT 4 identified in step S43 and the source converted into the connection number. The management device 1 then receives the message, and the process ends.

[0114] Next, the process of updating the aggregation information when a new network device 6 is added to be managed by management device 1 will be described with reference to Fig. 18. Fig. 18 is a flowchart showing an example of the flow of the process executed by aggregation device 2, from updating the aggregation information to submitting an application for addition to management device 1.

[0115] In step S51, the aggregation information update unit 204 of the aggregation device 2 receives a request to add a new network device 6 from the network device 6 or the like.

[0116] In step S52, the aggregation information update unit 204 causes the confirmation processing unit 201 to execute a confirmation process for the activation state of the new network device 6.

[0117] In step S53, the aggregated information update unit 204 acquires the connection unit information of the network device 6 that is the target of the activation state confirmation process in step S52.

[0118] In step S54, the aggregation information update unit 204 updates the aggregation information by assigning a connection number based on the connection information acquired in step S53 to an available connection number of the virtual device registered in step S22.

[0119] In step S55, the aggregated information update unit 204 requests the management device 1 to add the aggregated information updated in step S54, and then ends the process.

[0120] Second Embodiment Next, a communication system 100 according to the second embodiment will be described. In the following description, the same components as those in the first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0121] The communication system 100 according to the second embodiment includes a management device 1, an aggregation device 2, a plurality of network devices 6 such as a network switch 3 and an OLT 4, and a plurality of communication devices such as an ONU 51 connected to the network devices 6.

[0122] The communication system 100 according to the second embodiment differs from the first embodiment mainly in the configuration of the functional blocks of the processors 10A and 20A that realize the centralized management processing. For example, in the centralized management processing of the first embodiment, the forwarding processing unit 203 of the aggregation device 2 distributes messages transmitted and received between the management device 1 and the network device 6 to the correct destination. On the other hand, in this embodiment, messages are transmitted and received between the management device 1 and the network device 6 using a general-purpose address conversion function and a routing function. Details of the centralized management processing by the processors 10A and 20A according to this embodiment will be described using as an example a communication system 100 including one aggregation device 2 and four OLTs 4A, 4B, 4C, and 4D connected to the aggregation device 2, as shown in FIG. 19.

[0123] The functional configuration of the aggregation device 2 for performing aggregation management processing according to the second embodiment will be described with reference to FIG. 20. As shown in FIG. 20, the processor 20A includes a confirmation processing unit 201, an aggregation information generation unit 202A, and an aggregation information update unit 204A. In addition to these, the aggregation device 2 of this embodiment includes an address conversion unit 205A and a routing unit 206A. Note that in FIG. 20, only two OLTs 4 are shown for the sake of simplicity. The same applies to FIG. 21, which will be described later.

[0124] The aggregated information generating unit 202A generates aggregated information based on the device information acquired by the confirmation processing unit 201, and executes a process of transmitting the generated aggregated information to the management device 1.

[0125] The aggregated information generating unit 202A may generate aggregated information by performing the following processes (A) and (D), for example. (A) Based on the connection information acquired by the confirmation processing unit 201, the connections 60 of all the network devices 6 connected to the aggregation device 2 are aggregated into one or more virtual devices. (D) Each connection 60 of the network device 6 is assigned to each connection of the virtual device. A port number on the network device 6 side is assigned to each connection 60 of the network device 6. Here, the port number refers to a port number shared between the aggregation device 2 and each network device 6. Aggregation information is generated by associating each connection 60 of the virtual device with a port number on the management device 1 side. Here, the port number refers to a port number shared between the management device 1 and the aggregation device 2.

[0126] The address conversion unit 205A has general-purpose functions such as NAPT (Network Address Port Translation), and converts the IP address and port number included in a TCP (UDP) / IP packet into another IP address and port number. In this embodiment, the IP address of the virtual device and the port number shared between the management device 1 and the aggregation device 2 are converted into the IP address of each network device 6 and the port number shared between the aggregation device 2 and each network device 6.

[0127] The routing unit 206A has the function of a general-purpose router, is placed between the address conversion unit 205A and each network device 6, and transfers management messages to each network device 6 based on the IP address converted by the address conversion unit 205A. In this embodiment, these general-purpose functions can realize a function equivalent to the transfer process in the first embodiment.

[0128] 22 shows an example of a network device table included in the aggregated information generated by the aggregated information generating unit 202A in the communication system 100 shown in FIG. 19. As shown in FIG. 22, in the aggregated information of this embodiment, the connection number of the virtual device is associated with the connection number of the actual network device 6. Specifically, as shown in FIG. 22, the connection number of the virtual device is associated with the connection number of the actual OLT 4 by combining the identification information and connection number of the virtual OLT 4 with the identification information and connection number of the actual OLT 4. For example, the connection of the virtual device having identification information "V1" and connection number "4" is associated with the connection 60 of the network device 6 having identification information "B" and connection number "1". Furthermore, in this embodiment, a port number shared between the aggregation device 2 and the network device 6 (hereinafter referred to as the port number on the network device 6 side) is assigned to each connection 72 of the actual OLT 4. For example, the connection unit 60 of the network device 6 having the identification information "B" and the connection unit number "1" is associated with the port number "E4" on the network device 6 side.

[0129] Furthermore, in this embodiment, the aggregation information generation unit 202A generates the management device table shown in Fig. 23 in addition to the network device table of Fig. 22. The management device table shown in Fig. 23 associates the connection number of the virtual device with the port number shared between the management device 1 and aggregation device 2 (hereinafter referred to as the port number on the management device 1 side). The aggregation device 2 shares the network device table of Fig. 22 with the network device 6 and stores it in the address conversion unit 205A. The aggregation device 2 also transmits the management device table of Fig. 23 to the management device 1.

[0130] When a request for adding a new network device 6 is received, the aggregation information update unit 204A executes a process to update the aggregation information to include information about the new network device 6. For example, when the aggregation information update unit 204A receives a request for adding a new network device 6, it causes the confirmation processing unit 201 to execute a startup status confirmation process and acquire device information about the newly added network device 6. The aggregation information update unit 204A assigns a connection number based on the connection information of the newly added network device 6 to an available connection number of the virtual device, assigns a port number on the network device 6 side to the added connection 60, and updates the network device table by associating the connection number of the virtual device with the connection number of the new network device 6. The aggregation information update unit 204A shares the updated information with the network device 6 and stores it in the address conversion unit 205A. It updates the management device table, which associates the connection number of the virtual device with the port number on the management device 1 side. Then, the aggregation information update unit 204A sends the updated management device table to the management device 1 to request the addition.

[0131] Furthermore, when there is a request to delete a network device 6 that is under management by the management device 1, the aggregation information update unit 204A executes a process of updating the aggregation information to information that removes information related to the network device 6 to be deleted. For example, when the aggregation information update unit 204A receives a request to delete a network device 6, it updates the aggregation information by removing the identification information of the network device 6 to be deleted and the connection number of each connection 60 that the network device 6 has from the connection number of the virtual device. It also updates the table that associates the connection number of the virtual device with the port number on the management device 1 side. The aggregation information update unit 204A then sends the updated management device table to the management device 1 to request deletion.

[0132] Next, a description will be given of the functional configuration of management device 1 for performing the centralized management process. The centralized management process by management device 1 is mainly realized by processor 10A. As shown in Fig. 21, processor 10A includes an aggregation information acquisition unit 101A and a communication management unit 102A.

[0133] The aggregated information acquisition unit 101A executes a process of acquiring aggregated information generated by the aggregated information generation unit 202A of the aggregation device 2 or updated by the aggregated information update unit 204A. In this embodiment, the aggregated information acquisition unit 101A transmits to the aggregation device 2 a device registration signal that causes the aggregation device 2 to start acquiring device information, thereby causing the aggregation device 2 to acquire device information and generate aggregated information. Furthermore, when the aggregation information acquisition unit 101A receives from the aggregation device 2 an application for addition or deletion of a network device 6, it acquires the updated aggregated information from the aggregation device 2.

[0134] The communication management unit 102A registers and manages each network device 6 included in the communication network NW as a virtual device based on the aggregated information acquired by the aggregated information acquisition unit 101A. In the example shown in Fig. 22, the management device 1 registers and manages real OLT4A and real OLT4B, each having three connection units 72, as a virtual OLT4V1 having six connection units 72, and real OLT4C and real OLT4D, each having three connection units 72, as a virtual OLT4V2 having six connection units 72. As a result, instead of registering and managing four real OLTs 4 individually, they are registered and managed as two virtual OLTs 4, which reduces the number of objects to be managed and controlled, and simplifies the processing for managing the mapping of OLTs, etc.

[0135] When the management device 1 performs communication, the communication management unit 102A refers to the management device table shown in Fig. 23 and identifies the virtual OLT4V and the connection unit 72. Then, it transmits a message specifying the identification number (IP address, etc.) of the virtual OLT4V and the port number on the management device 1 side. Furthermore, when a message is received, the communication management unit 102A refers to the management device table shown in Fig. 23 and identifies the virtual OLT4V and the connection unit from the identification number (IP address, etc.) of the virtual OLT4V and the port number on the management device 1 side.

[0136] Next, an example of the process flow for registering device information of a network device 6 and performing communication between the management device 1 and each network device 6 in the communication system 100 of the second embodiment will be described with reference to Fig. 24. Fig. 24 is a sequence diagram showing an example of the process flow from the registration process of the network device 6 to the transmission and reception of data. Fig. 24 explains the process between one management device 1, one aggregation device 2, and two OLTs 4, OLT4A and OLT4B, connected to this aggregation device 2, as an example.

[0137] 24, in step S201, the management device 1 starts registering information about the network devices 6 connected to the aggregation device 2. The management device 1 causes the aggregation device 2 to check the startup status of the multiple network devices 6 connected to the aggregation device 2 and obtain device information about them.

[0138] In step S202, the aggregation device 2 transmits a signal to the OLT 4A to check the activation state of the OLT 4A.

[0139] In step S203, the aggregation device 2 receives device information including its state, identification information, and connection part information from the OLT 4A.

[0140] In step S204, the aggregation device 2 transmits a signal to the OLT 4B to check the activation state of the OLT 4B.

[0141] In step S205, the aggregation device 2 receives device information including its state, identification information, and connection part information from the OLT 4B.

[0142] In step S206, the aggregation device 2 generates aggregated information based on the device information acquired in steps S203 and S205, and transmits the generated aggregated information to the management device 1. The aggregated information includes identification information for each network device 6, and includes a network device table in which the connection number of the virtual device is associated with the connection number of the network device 6. As shown in FIG. 22, the network device table also includes information in which the connection number of the network device 6 is associated with the port number on the network device 6 side. IP addresses and MAC addresses are used as identification information for the virtual device and the network device 6. The aggregation device 2 also generates the management device table shown in FIG. 23 in which the connection number of the virtual device is associated with the port number on the management device 1 side. The aggregation device 2 transmits the management device table shown in FIG. 23 to the management device 1, and retains the network device table shown in FIG. 22, using it for address translation function and sharing it with the network device 6.

[0143] In step S207, the management device 1 registers information about the virtual OLT 4 as the network device 6 connected to the aggregation device 2 based on the aggregation information. Thereafter, communication between the management device 1 and the aggregation device 2 is specified by the identification number of the virtual OLT 4 and the port number on the management device 1 side. In addition, communication between the aggregation device 2 and the network device 6 is specified by the identification number of the network device 6 and the port number on the network device 6 side.

[0144] In step S208, the management device 1 specifies the identification number of the virtual OLT 4 and the port number on the management device 1 side that correspond to the virtual OLT 4 and the connection number of the virtual OLT 4, based on the information in the management device table shown in Fig. 23, and sends a management message to the aggregation device 2. The aggregation device 2 converts the received identification number of the virtual OLT 4 and the port number on the management device 1 side into the identification number of the real OLT 4 and the port number on the network device 6 side, based on the information in the network device table shown in Fig. 22 held in the address conversion function. Then, based on the converted identification number and the port number on the network device 6 side, it forwards the management message to the real OLT 4 using the routing function. The real OLT 4 identifies the connection based on the port number on the network device 6 side of the received management message and performs control.

[0145] Next, an example of processing when a new OLT4C is registered in the management device 1 in the communication system 100 shown in Fig. 25 will be described with reference to Fig. 25. Fig. 25 is a sequence diagram showing an example of processing when an OLT4C newly connected to the aggregation device 2 is registered in a state where OLT4A and OLT4B are registered in the management device 1 (step S207). In Fig. 25, OLT4A and OLT4B are registered in the management device 1, and OLT4C is newly connected to the connection unit 27 of the aggregation device 2.

[0146] In step S211, a communication connection is established between the aggregation device 2 and the OLT4C. For example, the aggregation device 2 performs a process of checking the startup status with the OLT4C and acquires connection part information held by the OLT4C. The connection establishment may be initiated by the aggregation device 2, which has received a request to add the OLT4C, sending a connection request to the OLT4C, or by the OLT4C sending a connection request to the aggregation device 2.

[0147] In step S212, the aggregation device 2 receives device information including its state, identification information, and connection part information from the OLT 4C.

[0148] In step S213, the aggregation device 2 updates the aggregation information based on the device information of OLT4C acquired in step S212. The updated aggregation information includes identification information of OLT4C and includes a network device table including information associating the connection number of a virtual device with the connection number of OLT4C and information associating the connection number of OLT4C with a port number on the OLT4C side. The updated aggregation information also includes a management device table associating the connection number of a virtual device corresponding to OLT4C with the connection number on the management device 1 side of the aggregation device 2. The aggregation device 2 transmits the updated management device table to the management device 1.

[0149] In step S214, the management device 1 registers information relating to the virtual OLT 4 including the OLT 4C connected to the aggregation device 2 based on the aggregation information updated in step S213.

[0150] In step S215, the management device 1 controls the OLT 4C in the same manner as in step S208, based on the aggregation information updated in step S214.

[0151] Specifically, in step S215, the management device 1 specifies the identification number of the virtual OLT 4 corresponding to OLT 4C and the port number on the management device 1 side based on the information in the management device table acquired in step S213, and transmits a management message to the aggregation device 2. The aggregation device 2 converts the received identification number of the virtual OLT 4 and the port number on the management device 1 side into the identification number of the real OLT 4 and the port number on the network device 6 side based on the information in the network device table held in the address conversion unit 205A and updated in step S213. Then, based on the converted identification number and the port number on the network device 6 side, the routing unit 206A transfers the management message to the real OLT 4C. The real OLT 4C identifies the connection part based on the port number on the network device 6 side of the received management message and performs control.

[0152] Next, an example of the aggregation management process executed by the aggregation device 2 according to the second embodiment will be described. First, the process up to the point where information on the network device 6 connected to the aggregation device 2 is transmitted to the management device 1 will be described. Fig. 26 is a flowchart showing an example of the flow of the process up to the point where the aggregation information is transmitted to the management device 1 in the aggregation management process executed by the aggregation device 2.

[0153] As shown in FIG. 26, in step S61, the confirmation processing unit 201 of the aggregation device 2 performs a process of confirming the activation status of the plurality of network devices 6 connected to the aggregation device 2.

[0154] In step S62, the confirmation processing unit 201 acquires device information including connection information of the plurality of network devices 6 that are the targets of the startup state confirmation processing in step S61 and are running.

[0155] In step S63, the aggregation information generation unit 202A aggregates the multiple connections 60 indicated by the connection information of the multiple network devices 6 acquired in step S62 into one or more virtual devices. Specifically, the aggregation information generation unit 202A sets a number of virtual devices that is fewer than the number of network devices 6 connected to the aggregation device 2 indicated by the device information acquired in step S62. Then, the aggregation information generation unit 202A aggregates the connections 60 of all activated network devices 6 indicated by the device information acquired in step S62 into the set virtual device.

[0156] In step S64, the aggregated information generation unit 202A assigns each connection unit 60 of the network device 6 to each connection unit of the virtual device set in step S63, assigns a port number on the network device 6 side to each connection unit 60, and generates a network device table. The aggregated information generation unit 202A further associates each connection unit 60 of the virtual device with a port number on the management device 1 side to generate a management device table, and combines it with the network device table to form aggregated information.

[0157] In step S65, the aggregated information generating unit 202A transmits the network device table of the aggregated information generated in step S64 to the network device 6, and transmits the management device table to the management device 1.

[0158] Next, an example of the aggregation management process executed by management device 1 according to this embodiment will be described. First, the process up to the point where information about network device 6 connected to aggregation device 2 is registered in management device 1 will be described. Figure 27 is a flowchart showing an example of the flow of the process up to the point where management device 1 registers information about network device 6 in the aggregation management process executed by management device 1.

[0159] In step S71, the aggregation information acquisition unit 101 of the management device 1 acquires the management device table from the aggregation information transmitted from the aggregation device 2 in step S65.

[0160] In step S72, the communication management unit 102 registers the plurality of network devices 6 as virtual devices in the storage unit 13 based on the aggregation information acquired from the aggregation device 2 in step S71.

[0161] Next, a process of transmitting a management message from the management device 1 to the network device 6 in a state where information about the network device 6 as a virtual device has been registered in the management device 1 will be described with reference to Fig. 28. Fig. 28 is a diagram showing an example of the process up to transmission of a management message from the management device 1 to the OLT 4.

[0162] As shown in FIG. 28, in step S81, the communication management unit 102A of the management device 1 refers to the management device table acquired in step S71, and transmits a management message to the desired connection number of the virtual OLT 4.

[0163] In step S82, the management message is transmitted via the aggregation device 2 to the connection number of the real OLT corresponding to the connection number of the virtual OLT 4 as the destination.

[0164] Next, the process of updating the aggregation information when a new network device 6 is added to be managed by the management device 1 will be described with reference to Fig. 29. Fig. 29 is a flowchart showing an example of the flow of the process executed by the aggregation device 2 of the second embodiment, from updating the aggregation information to submitting an application for addition to the management device 1.

[0165] In step S91, the aggregation information update unit 204A of the aggregation device 2 receives a request to add a new network device 6 from the network device 6 or the like.

[0166] In step S92, the aggregation information update unit 204A causes the confirmation processing unit 201 to execute a confirmation process for the activation state of the new network device 6.

[0167] In step S93, the aggregated information update unit 204A acquires the connection unit information of the network device 6 that is the target of the activation state confirmation process in step S92.

[0168] In step S94, the aggregation information update unit 204A assigns the connection number based on the connection information acquired in step S93 to the available connection number of the virtual device registered in step S72, assigns the port number on the network device 6 side to the added connection 60, and updates the network device table by associating the connection number of the virtual device with the connection number of the new network device 6. The aggregation information update unit 204A shares the updated information with the network device 6 and stores it in the address translation function. It updates the management device table that associates the connection number of the virtual device with the port number on the management device 1 side.

[0169] In step S95, the aggregated information update unit 204A requests the management device 1 to add the aggregated information updated in step S94, and then ends the process.

[0170] In the second embodiment, the connection unit 72 of the actual OLT 4 is identified by the port number, but the connection unit 72 may be identified by other means, for example, by description in the management message. In this case, the aggregation device 2 is responsible for the function up to routing the management message based on the identification information.

[0171] According to the embodiment described above, the following effects are achieved.

[0172] The communication system 100 according to the first embodiment comprises a plurality of network devices 6, an aggregation device 2 to which the plurality of network devices 6 are connected, and a management device 1 capable of communicating with the plurality of network devices 6 via the aggregation device 2 and managing the communications of the plurality of network devices 6. The aggregation device 2 performs a startup status confirmation process with all of the connected network devices 6 to obtain connection information held by the network devices 6, aggregates the connections 60 of all of the network devices 6 into one or more virtual devices based on the connection information, and generates aggregated information in which the connection number of the network device 6 is assigned to each connection 7 of the virtual devices. The virtual devices are fewer in number than the network devices 6 that are actually connected, and transmits the aggregated information to the management device 1. The management device 1 manages all of the network devices 6 connected to the aggregation device 2 based on the aggregated information.

[0173] This allows the management device 1 to manage multiple network devices 6 as if they were aggregated into a number smaller than the actual number, preventing the number of objects that the management device 1 registers and manages and controls from increasing and making management more complicated.

[0174] Here, for example, in a communication network NW in which a large number of ONUs 51 and the like are connected to each OLT 4, as the number of OLTs 4 increases, the processing related to mapping and display for each OLT 4 becomes more complicated. According to this embodiment, the management device 1 registers and manages a smaller number of actual OLTs 4 as virtual devices, which makes management easier for the management device 1 and reduces the processing load. Therefore, the burden on the management device 1 of managing a plurality of communication devices including the network device 6 can be reduced.

[0175] Furthermore, in the communication system 100 according to the first embodiment, the management device 1 refers to the aggregation information and transmits a management message to the connection number of the virtual device, and when the aggregation device 2 receives the management message, it identifies the connection number of the network device 6 that corresponds to the connection number of the virtual device and transmits the management message to the connection number of the identified network device 6.

[0176] As a result, the aggregation device 2 takes charge of the process of distributing messages from the management device 1 to the network device 6 to appropriate destinations, and the processing load on the management device 1 can be further reduced.

[0177] Furthermore, in the communication system 100 according to the first embodiment, when a response is received from a network device 6, the aggregation device 2 identifies the connection number of the virtual device corresponding to the connection number of the network device 6, and transmits to the management device 1 information that a response has been received from the identified connection number.

[0178] This allows messages sent from the network device 6 to appear to the management device 1 as if they were sent from a virtual device, thereby reliably reducing the load on the management device 1 in managing the network device 6.

[0179] Furthermore, in the communication system 100 according to the first embodiment, when a request is made to add a new network device 6, the aggregation device 2 performs a startup status confirmation process with the new network device 6 to obtain the connection information of the network device 6, assigns a connection number based on the connection information to an available connection number of the virtual device, updates the aggregation information, and sends the updated aggregation information to the management device 1 to request the addition.

[0180] As a result, even when a network device 6 to be managed by the management device 1 is added, an increase in the load of the management device 1 in managing the network device 6 can be suppressed.

[0181] Furthermore, in the communication system 100 according to the first embodiment, when a request is made to delete a network device 6, the aggregation device 2 removes the connection number based on the connection information held by the network device 6 from the connection number of the virtual device, updates the aggregation information, and sends the updated aggregation information to the management device 1 to request deletion.

[0182] As a result, even if the number of network devices 6 to be managed by the management device 1 decreases, the load of management of the network devices 6 by the management device 1 can be reliably reduced.

[0183] In addition, in the communication system 100 according to the second embodiment, the aggregation device 2 assigns each connection unit 60 on the network device 6 side to each connection unit of the virtual device, assigns a port number on the network device 6 side to each connection unit 60, generates aggregation information, and transmits the aggregation information to the management device 1. The aggregation device 2 has an address conversion unit 205A and a routing unit 206A based on the aggregation information.

[0184] As a result, the message is automatically transferred from the aggregation device 2 to the destination network device 6, so that the processing load on the entire communication system 100 can be further reduced.

[0185] Furthermore, in the communication system 100 according to the second embodiment, when there is a request to add a new network device 6, the aggregation device 2 assigns a connection number based on the connection information of the newly added network device 6 to an available connection number of the virtual device, assigns a port number on the network device 6 side to the added connection 60, updates the aggregation information by associating the connection number of the virtual device with the connection number of the new network device 6, and sends the updated aggregation information to the management device 1 to request the addition.

[0186] As a result, even when a network device 6 to be managed by the management device 1 is added, an increase in the load of the management device 1 in managing the network device 6 can be suppressed.

[0187] Furthermore, in the communication system 100 according to the second embodiment, when a request is made to delete a network device 6, the aggregation device 2 removes the identification information of the network device 6 to be deleted and the connection number of each connection 60 of the network device 6 from the connection number of the virtual device, updates the aggregation information so that the connection number of the virtual device corresponds to the port number on the management device 1 side, and sends the updated aggregation information to the management device 1 to request deletion.

[0188] As a result, even if the number of network devices 6 to be managed by the management device 1 decreases, the load of management of the network devices 6 by the management device 1 can be reliably reduced.

[0189] The program of this embodiment is a program to be executed by a computer 16, 26 of a communication system 100 having a plurality of network devices 6, an aggregation device 2 to which the plurality of network devices 6 are connected, and a management device 1 that is capable of communicating with the plurality of network devices 6 via the aggregation device 2 and manages the communications of the plurality of network devices 6. The program includes the steps of controlling the aggregation device 2 to perform a startup status confirmation process with all connected network devices 6 to obtain connection information held by the network devices 6, and aggregating the connections 60 of all network devices 6 into one or more virtual devices based on the connection information; generating aggregation information in which the connection number of the network device 6 is assigned to each connection of the virtual device; transmitting the aggregation information to the management device 1; and managing all network devices 6 connected to the aggregation device 2 by the management device 1 based on the aggregation information, wherein the number of virtual devices is smaller than the number of network devices 6 that are actually connected.

[0190] The communication method of this embodiment is a communication method applied to a communication system 100 having a plurality of network devices 6, an aggregation device 2 to which the plurality of network devices 6 are connected, and a management device 1 that is capable of communicating with the plurality of network devices 6 via the aggregation device 2 and manages the communications of the plurality of network devices 6, and includes the steps of controlling the aggregation device 2 to perform a startup status confirmation process with all connected network devices 6 to obtain connection information held by the network devices 6, and aggregating the connections 60 of all network devices 6 into one or more virtual devices based on the connection information, generating aggregation information in which the connection number of the network device 6 is assigned to each connection of the virtual device, transmitting the aggregation information to the management device 1, and managing all network devices 6 connected to the aggregation device 2 by the management device 1 based on the aggregation information, wherein the number of virtual devices is smaller than the number of network devices 6 that are actually connected.

[0191] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate.

[0192] The communication system 100 according to the above embodiment includes a plurality of OLTs 4 and a plurality of network switches 3 as the network device 6, but may include only one of the OLTs 4 or the network switches 3. [Explanation of symbols]

[0193] 1 Management device 2 Aggregation Device 6 Network Devices 7, 9, 71, 72, 91, 92 Connections 16, 26 Program 60 Connection 100 Communication Systems 101, 101A Aggregated information acquisition unit 102, 102A Communication management department 201 Confirmation processing section 202, 202A Aggregated information generation unit 203 Transfer Processing Unit 204, 204A Aggregate information update section 205A Address conversion unit (address conversion means) 206A Routing unit (routing means)

Claims

1. a plurality of network devices; an aggregation device to which the plurality of network devices are connected; a management device that can communicate with the plurality of network devices via the aggregation device and manages communications between the plurality of network devices; The aggregation device A process for checking the startup status of all connected network devices is performed to acquire connection information of the network devices, and based on the connection information, the connections of all network devices are aggregated into one or more virtual devices; generating aggregated information in which the connection number of the network device is assigned to each connection of the virtual device, and transmitting the generated aggregated information to the management device; The number of virtual devices is less than the number of network devices actually connected; The management device manages all network devices connected to the aggregation device based on the aggregation information.

2. the management device refers to the aggregated information and transmits a management message to the connection number of the virtual device; The communication system described in claim 1, wherein when the aggregation device receives the management message, it identifies the connection number of the network device that corresponds to the connection number of the virtual device, and sends the management message to the connection number of the identified network device.

3. The communication system described in claim 2, wherein when the aggregation device receives a response from the network device, the aggregation device identifies the connection number of the virtual device corresponding to the connection number of the network device, and sends a notification to the management device that a response has been received from the identified connection number.

4. A communication system as described in any one of claims 1 to 3, wherein when a request is made to add a new network device, the aggregation device performs a startup status confirmation process with the new network device to obtain connection information held by the network device, assigns a connection number based on the connection information to an available connection number of a virtual device, updates the aggregation information, and sends the updated aggregation information to the management device to request the addition.

5. A communication system described in any one of claims 1 to 3, wherein when a request is made to delete a network device, the aggregation device updates the aggregation information by removing the connection number based on the connection information held by the network device from the connection number of the virtual device, and sends the updated aggregation information to the management device to request deletion.

6. the aggregation device assigns each connection unit on the network device side to each connection unit of the virtual device, assigns a port number on the network device side to each connection unit on the network device side, generates the aggregation information, and transmits the aggregation information to the management device; The communication system according to claim 1 , wherein the aggregation device includes address conversion means and routing means based on the aggregation information.

7. 7. The communication system of claim 6, wherein when a request is made to add a new network device, the aggregation device assigns a connection number based on the connection information of the newly added network device to an available connection number of the virtual device, assigns a port number on the network device side to the connection of the added network device, updates the aggregation information by associating the connection number of the virtual device with the connection number of the new network device, and sends the updated aggregation information to the management device to request the addition.

8. A communication system as described in claim 6 or 7, wherein when a request is made to delete a network device, the aggregation device removes the identification information of the network device to be deleted and the connection numbers of each connection part of the network device from the connection number of the virtual device, updates the aggregation information so that the connection number of the virtual device corresponds to the port number on the management device side, and sends the updated aggregation information to the management device to request deletion.

9. A program to be executed by a computer in a communication system including a plurality of network devices, an aggregation device to which the plurality of network devices are connected, and a management device capable of communicating with the plurality of network devices via the aggregation device and managing communications of the plurality of network devices, a step of controlling the aggregation device to perform a process of checking the startup status of all connected network devices, acquiring connection information of the network devices, and aggregating the connections of all network devices into one or more virtual devices based on the connection information; generating aggregated information in which a connection number of the network device is assigned to each connection of the virtual device; transmitting the aggregated information to the management device; and managing all network devices connected to the aggregation device based on the aggregation information by the management device; The program wherein the number of virtual devices is less than the number of network devices actually connected.

10. A communication method applied to a communication system including a plurality of network devices, an aggregation device to which the plurality of network devices are connected, and a management device capable of communicating with the plurality of network devices via the aggregation device and managing communications of the plurality of network devices, comprising: a step of controlling the aggregation device to perform a process of checking the startup status of all connected network devices, acquiring connection information of the network devices, and aggregating the connections of all network devices into one or more virtual devices based on the connection information; generating aggregated information in which a connection number of the network device is assigned to each connection of the virtual device; transmitting the aggregated information to the management device; and managing all network devices connected to the aggregation device based on the aggregation information by the management device; A communication method in which the number of virtual devices is less than the number of network devices actually connected.

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