Communication device, communication method, and program

Abstract

The purpose of the present invention is to provide a communication device that can simplify the monitoring of an optical communication network and quickly detect a failure. A communication device (10) according to this disclosure includes a communication unit (11) connected to an optical communication network for transmitting an optical signal, a management unit (12) that associates and manages a transmission time of the optical signal between a virtual device on the optical communication network and the communication unit (11) together with identification information of the virtual device, and a control unit (13) that, upon receiving a request message for requesting the transmission time of the optical signal between the virtual device and the communication unit (11), transmits a response message indicating the transmission time being managed in association with the identification information of the virtual device in response to the request message.

Description

[Technical field]

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

[0002] The amount of communication traffic has been increasing at an annual rate of more than 30% for the past 30 years. This has created a demand for large-scale networks, including the Internet, mobile networks, and networks between data centers.

[0003] On the other hand, most large-scale networks in recent years are IP networks that use Internet technology, but the high equipment and power costs per unit of communication capacity of IP networks are a problem.

[0004] In order to realize efficient, high-capacity communications in large-scale networks, it is expected that optical communication networks with excellent power efficiency will be wide-area and large-scaled by reducing the number of transfer points of packets or frames such as IP and switching optical signals. In recent years, it is also becoming possible in optical signal processing to perform switching in a short time equivalent to packet transfer.

[0005] However, an optical communication network looks just like a single cable to users who connect to the optical communication network from the outside. In other words, the optical communication network is equivalent to a black box to the users. Therefore, when optical communication networks are expanded in size and coverage, there is a possibility that problems will arise in managing the quality of the optical communication network and in fault monitoring.

[0006] Patent Document 1 discloses the configuration of an optical node device that converts only the header part of a packet transmitted through an optical communication network into an electrical signal and performs processing based on the contents of the converted header part. By converting only the header part of a packet from an optical signal to an electrical signal, when a fault occurs in the optical communication network, the optical node device can notify the end node of a packet with information such as an error message added.

[0007] Moreover, Patent Document 2 discloses a configuration in which a base station and an antenna device communicate with each other via an optical communication network. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2009-206978 A [Patent Document 2] JP 2019-140562 A Summary of the Invention [Problem to be solved by the invention]

[0009] When monitoring the communication quality or fault state of an optical communication network using the optical node device disclosed in Patent Document 1, it is necessary to perform conversion processing from optical signals to electrical signals. However, in order to further stabilize the communication quality, there is a demand for simplifying the monitoring processing of the optical communication network.

[0010] An object of the present disclosure is to provide a communication device, a communication method, and a program that can simplify the monitoring process of an optical communication network. [Means for solving the problem]

[0011] A communication device according to a first aspect of the present disclosure includes a communication unit connected to an optical communication network that transmits an optical signal, a management unit that manages a transmission time of the optical signal between a virtual device on the optical communication network and the communication unit in association with identification information of the virtual device, and a control unit that, when a request message requesting the transmission time of the optical signal between the virtual device and the communication unit is received, responds to the request message with a response message indicating the transmission time managed in association with the identification information of the virtual device.

[0012] A communication method according to a second aspect of the present disclosure manages, in association with each other, a transmission time of an optical signal between a virtual device and a communication device on an optical communication network that transmits the optical signal, and identification information of the virtual device, and when a request message requesting the transmission time of the optical signal between the virtual device and the communication device is received, responds to the request message with a response message indicating the transmission time managed in association with the identification information of the virtual device.

[0013] A program according to a third aspect of the present disclosure causes a computer to manage a transmission time of an optical signal between a virtual device and a communication device on an optical communication network that transmits the optical signal in association with identification information of the virtual device, and when a request message requesting the transmission time of the optical signal between the virtual device and the communication device is received, to respond to the request message with a response message indicating the transmission time managed in association with the identification information of the virtual device. Effect of the Invention

[0014] The present disclosure makes it possible to provide a communication device, a communication method, and a program that can simplify the monitoring process of an optical communication network. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a configuration diagram of a communication device according to a first embodiment. [Diagram 2] 4 is a diagram showing a flow of a communication method executed in the communication device according to the first embodiment. [Diagram 3] FIG. 11 is a configuration diagram of a communication network according to a second embodiment. [Figure 4] FIG. 11 is a configuration diagram of an optical communication device according to a second embodiment. [Diagram 5] FIG. 11 is a configuration diagram of a router according to a second embodiment. [Figure 6] FIG. 11 is a diagram illustrating a process flow when a user device according to the second embodiment executes a Ping. [Figure 7] FIG. 11 is a configuration diagram of a communication network according to a second embodiment. [Figure 8] FIG. 11 is a configuration diagram of a communication network according to a third embodiment. [Figure 9] FIG. 11 is a configuration diagram of a measuring instrument according to a third embodiment. [Figure 10] FIG. 11 is a configuration diagram of a communication network according to a third embodiment. [Figure 11] FIG. 11 is a configuration diagram of a communication network according to a fourth embodiment. [Figure 12] FIG. 13 is a configuration diagram of an optical switch according to a fourth embodiment. [Figure 13] 1A and 1B are configuration diagrams of a communication apparatus and an optical communication device according to respective embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (Embodiment 1) Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. First, a configuration example of a communication device 10 according to the first embodiment will be described with reference to FIG. 1. The communication device 10 may be a computer device that operates when a processor executes a program stored in a memory. The communication device 10 may be a router that converts an electrical signal into an optical signal, or a gateway device that converts an electrical signal into an optical signal.

[0017] The communication device 10 includes a communication unit 11, a management unit 12, and a control unit 13. The communication unit 11, the management unit 12, and the control unit 13 may be software or modules that perform processing by a processor executing a program stored in a memory. Alternatively, the communication unit 11, the management unit 12, and the control unit 13 may be hardware such as a circuit or a chip.

[0018] The communication unit 11 is connected to an optical communication network that transmits optical signals. The optical communication network may be, for example, a network configured by optical fibers. The optical communication network may be configured by optical communication devices. The optical communication devices may be, for example, splitters, amplifiers, attenuators, or switches. The optical communication network may be configured by connecting optical communication devices using optical fibers. The splitters separate or aggregate optical communication lines that are communication paths in the optical communication network. The amplifiers amplify optical signals, and the attenuators attenuate optical signals. The optical communication network transmits optical signals to an optical signal terminal device without converting them into electrical signals. The optical signal terminal device may be, for example, a router that terminates packets, or may be an ONU (Optical Network Unit).

[0019] The communication unit 11 being connected to the optical communication network may mean that the communication unit 11 is capable of outputting an optical signal to the optical communication network and further capable of receiving an optical signal from the optical communication network.

[0020] The management unit 12 manages the transmission time of the optical signal between the virtual device on the optical communication network and the communication unit 11 in association with the identification information of the virtual device. The optical communication network does not terminate the optical signal. Therefore, an external device that transmits data to the optical communication network via the communication device 10 recognizes the optical communication network as a single cable such as an optical fiber. In other words, the external device cannot transmit a signal or message addressed to the optical communication device in order to monitor or manage the optical communication device on the optical communication network. Furthermore, even if the external device transmits a signal or message to the optical communication device, it cannot receive a response signal from the optical communication device.

[0021] The virtual device may be a virtual device that behaves as if it receives a signal from an external device in an optical communication network and transmits a response signal to the external device. For example, an optical communication device may be defined as a virtual device, and the virtual device may be defined as existing in a location where no optical communication device actually exists.

[0022] The transmission time of an optical signal between the virtual device and the communication unit 11 may be, for example, the time from when the virtual device transmits an optical signal to when the communication unit 11 receives the optical signal. Alternatively, it may be the time from when the communication unit 11 transmits an optical signal to when the virtual device receives the optical signal. The transmission time may be rephrased as a transmission delay or a delay time.

[0023] The transmission time may be determined, for example, according to the distance between the virtual device and the communication unit 11. Alternatively, when laying an optical communication network, the transmission time between the communication unit 11 and the virtual device may be measured using a measuring device or the like.

[0024] The identification information of the virtual device may be, for example, address information assigned to the virtual device, and the address information may be, for example, an IP address.

[0025] When the control unit 13 receives a request message requesting the transmission time of the optical signal between the virtual device and the communication unit 11, it responds to the request message with a response message indicating the transmission time managed in association with the identification information of the virtual device.

[0026] The request message is transmitted to the communication device 10 from an external device that transmits data to the optical communication network via the communication device 10 or receives data from the optical communication network via the communication device 10. The external device is a device managed by a user who uses the optical communication network, and may be referred to as a user device or a user apparatus. The user device or the user apparatus is a computer device. The request message includes identification information of the virtual device. When the control unit 13 receives the request message transmitted from the communication device 10, the control unit 13 acquires information on the transmission time that is managed in association with the identification information of the virtual device from the management unit 12. Acquiring may be rephrased as selecting or extracting, for example.

[0027] The control unit 13 may include information indicating a transmission time between the communication unit 11 and the virtual device in the response message. Alternatively, the control unit 13 may transmit the response message to the external device via the communication unit 11 after a transmission time has elapsed after receiving the request message.

[0028] Next, the flow of communication processing in the communication device 10 will be described with reference to Fig. 2. First, the transmission time of an optical signal between a virtual device on an optical communication network and the communication unit 11 is managed in association with identification information of the virtual device (S11). Next, when the management unit 12 receives a request message requesting the transmission time of an optical signal between the virtual device and the communication unit 11, the management unit 12 responds to the request message with information indicating the transmission time managed in association with the identification information of the virtual device (S12). The management unit 12 includes information indicating the transmission time in the response message and transmits the response message to the device that is the sender of the request message.

[0029] As described above, the communication device 10 transmits a response message indicating the transmission time managed in advance to the external device in response to a request message received from the external device. This allows the communication device 10 to transmit a response message indicating the transmission time to the external device without converting an optical signal into an electrical signal in the optical communication network. As a result, the communication device 10 can simplify the monitoring process of the optical communication network in the external device.

[0030] Since the external device can recognize the transmission time in a specific section in the optical communication network, the external device can manage the communication quality in the optical communication network. As a result, the external device can perform network design using the optical communication network based on the communication quality in the optical communication network.

[0031] (Embodiment 2) Next, a configuration example of a communication system according to the second embodiment will be described with reference to FIG. 3. The communication network in FIG. 3 includes a router 20, a router 30, an optical communication device 40, an optical communication device 50, a user device 60, and an external device 70. The router 20 and the router 30 may be referred to as router devices. The routers 20 and 30 correspond to the communication device 10 in FIG. 1. The optical communication devices 40 and 50 may be, for example, a splitter, an amplifier, an attenuator, or a switch. The user device 60 may be a computer device having a communication function. The external device 70 may be a server device or a user device. The user device 60 and the external device 70 may also be routers.

[0032] The routers 20 and 30 are connected to an optical communication network. That is, the router 20 converts an electrical signal received from the user device 60 into an optical signal and transmits the optical signal to the optical communication device 40. Furthermore, the router 20 converts an optical signal received from the optical communication device 40 into an electrical signal and transmits the electrical signal to the user device 60. The router 30, like the router 20, also converts an optical signal into an electrical signal and then converts an electrical signal into an optical signal between the external device 70 and the optical communication device 50. A device having a function of converting between an optical signal and an electrical signal may be connected to the routers 20 and 30. Alternatively, the communication unit 11 of the routers 20 and 30 may have a function of converting between an optical signal and an electrical signal.

[0033] The routers 20 and 30 are the end points of optical communication paths set on an optical communication network. The routers 20 and 30 relay IP data transmission between a user device 60 and an external device 70.

[0034] The routers 20 and 30 are IP routers, and use ICMP (Internet Control Message Protocol) with an echo request set as control communication for grasping the network state. In addition, when an Ethernet (registered trademark) switch or an MPLS (Multi Protocol Label Switching) router is used instead of the routers 20 and 30, OAM (Operations, Administration, Management) may be used as control communication.

[0035] For example, the router 20 makes a pseudo reply or response to a message (ICMP message) related to control communication received from the user device 60 as if the optical communication device 40 or the optical communication device 50 had responded. Furthermore, the routers 20 and 30 advertise a virtual IP communication path in the optical communication network to the user device 60 and the external device 70 by using an IP route exchange protocol, thereby providing IP communication. The route exchange protocol may be, for example, BGP (Border Gateway Protocol).

[0036] The optical communication devices 40 and 50 measure the power of an optical signal and detect a drop in the signal level due to a defect in an optical fiber or the like. The signal level may be rephrased as, for example, a received light level. For example, the optical communication devices 40 and 50 may detect a drop in the signal level that is so low that communication is impossible, or may detect a drop in the signal level that allows communication but causes degradation of communication quality.

[0037] Here, a description will be given of the router 20 making a pseudo response to an ICMP message in which an echo request is set. In the following description, an ICMP message in which an echo request is set will be referred to as an ICMP Echo. The router 30 has the same functions as the router 20, and a detailed description will be omitted.

[0038] Since the optical communication network is premised on transmitting optical signals to a terminal device without converting the optical signals into electrical signals, the optical communication devices 40 and 50 constituting the optical communication network do not perform processing related to IP packets. In other words, even if the user equipment 60 uses ICMP Echo, the optical communication devices 40 and 50 cannot respond with an ICMP message with an echo reply set. In the following, an ICMP message with an echo reply set will be described as an ICMP Echo reply. As a result, the user equipment 60 cannot detect the optical communication devices 40 and 50 constituting the optical communication network using IP control signals using ICMP or the like.

[0039] Since the user equipment 60 cannot detect the optical communication devices 40 and 50, for example, the user equipment 60 receives ICMP Echo replies only from the routers 20 and 30. Therefore, the user equipment 60 can only measure the transmission time between the user equipment 60 and the router 20 or between the user equipment 60 and the router 30, and can only check the continuity with the router 20 or the router 30. In the future, in a large-scale optical communication network in which the optical communication path is extended, the section that becomes a black box will become large. Therefore, even if a failure that affects communication performance occurs in the optical communication network, the user who manages the user equipment 60 cannot get a clue to know the cause of the failure.

[0040] Therefore, in the present disclosure, the routers 20 and 30 and the optical communication devices 40 and 50 are provided with a virtualization function required for the routers 20 and 30 to perform a pseudo response to an ICMP Echo.

[0041] Next, a configuration example of the optical communication device 40 will be described with reference to FIG. 4. The optical communication device 50 has the same configuration as the optical communication device 40, and therefore a detailed description thereof will be omitted. The optical communication device 40 has a connector 41, a connector 42, a coupler 43, and a virtual device unit 44. The virtual device unit 44 may be software or a module in which processing is performed by a processor executing a program stored in a memory. In FIG. 4, the optical communication device 40 has a configuration in which the virtual device unit 44 is included, but the virtual device unit 44 may be provided in a device different from the optical communication device 40. In this case, the optical communication device 40 may be connected to a device equipped with the virtual device unit 44 via a wired cable, via a network, or via a wireless communication line.

[0042] The connectors 41 and 42 are, for example, optical fiber connectors, and are connected to optical fibers that form an optical communication path. In addition, a virtual address is assigned to each of the connectors 41 and 42. The virtual address may be in the form of, for example, an IP address. That is, the virtual address may be referred to as a virtual IP address. For example, an administrator who manages the optical communication network may determine the virtual addresses to be assigned to the connectors 41 and 42. The connector 41 may be connected to an optical communication device 50 via an optical fiber, and the connector 42 may be connected to a router 20 via an optical fiber.

[0043] The coupler 43 is, for example, an optical fiber coupler, and branches a part of the optical signal received from the connector 41 or the connector 42. The coupler 43 outputs, for example, the optical signal received from the connector 41 or the connector 42 to the connector 42 or the connector 41, and outputs a part of the branched optical signal to the virtual device unit 44. Also, in Fig. 4, the connector 41, the connector 42, and the coupler 43 are illustrated one by one on the assumption that one optical fiber is used for bidirectional communication, but when used for unidirectional communication, each of them may be used in pairs.

[0044] The virtual device unit 44 has a virtual device control unit 45 and an optical power meter 46. The optical power meter 46 measures the power of the optical signal received from the coupler 43. The virtual device control unit 45 determines whether the power of the optical signal measured by the optical power meter 46 is within a preset range. In other words, the virtual device control unit 45 determines whether the power of the optical signal measured by the optical power meter 46 is equal to or lower than the lower limit of the preset range. The lower limit of the preset range may be referred to as a threshold.

[0045] The power of the optical signal that is equal to or lower than the lower limit of the preset range may be a signal level that is so low that communication is impossible, or may be a signal level that allows communication but causes degradation of communication quality. When the power of the optical signal measured by the optical power meter 46 is equal to or lower than the lower limit of the preset range, this indicates that there is a possibility that a fault has occurred in the optical fiber connected to the connector 41 or the connector 42.

[0046] The virtual device control unit 45 transmits the determination result to the router 20 to which the user device 60 is connected. The virtual device control unit 45 may also transmit the determination result to the router 20 and the router 30. The virtual device control unit 45 may transmit the determination result to the router 20 via a network different from the optical communication network configured using the routers 20 and 30 and the optical communication devices 40 and 50, for example. If the optical communication network is a service network that provides communication services to the user device 60 and the external device 70, the network used by the optical communication device 40 to transmit the determination result to the router 20 may be a maintenance network. The maintenance network may be an IP network and may be an optical communication network different from the optical communication network configured using the routers 20 and 30 and the optical communication devices 40 and 50.

[0047] Next, a configuration example of the router 20 according to the second embodiment will be described with reference to Fig. 5. The router 30 has the same configuration as the router 20, and therefore a detailed description thereof will be omitted. The router 20 has an optical signal processing unit 21, a frame processing unit 22, a packet forwarding unit 23, an input / output processing unit 24, a frame processing unit 25, and a virtual router unit 26. Each of the components constituting the router 20 may be software or a module in which processing is performed by a processor executing a program stored in a memory. Alternatively, each of the components constituting the router 20 may be hardware such as a circuit or a chip.

[0048] The optical signal processing unit 21 extracts a communication frame of an optical signal received from the optical communication network, and outputs the extracted communication frame to the frame processing unit 22. The optical signal received by the optical signal processing unit 21 from the optical communication network may be rephrased as an optical signal received via an optical fiber. Alternatively, the optical signal processing unit 21 transmits the communication frame received from the frame processing unit 22 to the optical communication network as an optical signal. A virtual address is assigned to the optical signal processing unit 21.

[0049] The frame processing unit 22 extracts packets from the communication frame received from the optical signal processing unit 21, and outputs the extracted packets to the packet forwarding unit 23. Alternatively, the frame processing unit 22 converts the packets received from the packet forwarding unit 23 into frames, and outputs the framed communication frames to the optical signal processing unit 21.

[0050] The input / output processing unit 24 extracts a communication frame of the communication data received from the user device 60, and outputs the extracted communication frame to the frame processing unit 25. Alternatively, the input / output processing unit 24 transmits the communication frame received from the frame processing unit 25 to the user device 60.

[0051] The packet forwarding unit 23 refers to the destination written in the packet and forwards the packet to the frame processing unit 22 or the frame processing unit 25. Furthermore, when the packet forwarding unit 23 receives a control packet whose destination is a virtual address assigned to a connector of the optical communication device 40 or 50, it outputs the control packet to the control packet processing unit 28. Here, it is assumed that the control packet processing unit 28 receives an ICMP Echo with a virtual address set as the destination as a control packet.

[0052] Next, a description will be given of the function or operation of the virtual router unit 26. The virtual router unit 26 includes a virtual network control unit 27 and a control packet processing unit .

[0053] The control packet processing unit 28 outputs the control packet received from the packet forwarding unit 23 to the virtual network control unit 27. Alternatively, the control packet processing unit 28 outputs the control packet received from the virtual network control unit 27 to the packet forwarding unit 23.

[0054] The virtual network control unit 27 holds in advance information regarding the round-trip transmission time of the optical signal between the optical signal processing unit 21 and the optical communication devices 40 and 50 present in the optical communication network. For example, the virtual network control unit 27 manages the virtual addresses assigned to the optical communication devices in association with the round-trip transmission times of the optical signal. Specifically, the virtual network control unit 27 manages the round-trip transmission time between the optical signal processing unit 21 and the optical communication device 40 in association with the virtual address assigned to the connector 42 of the optical communication device 40. Furthermore, the virtual network control unit 27 manages the round-trip transmission time between the optical signal processing unit 21 and the optical communication device 50 in association with the virtual address assigned to the connector 42 of the optical communication device 50.

[0055] Furthermore, the virtual network control unit 27 manages the determination results of the power of the optical signals received via the maintenance network in the optical communication devices 40 and 50. The determination results indicate, for example, whether the power of the optical signals received in the optical communication devices 40 and 50 is within a preset range.

[0056] When the virtual network control unit 27 receives an ICMP Echo with a virtual address set as the destination from the packet forwarding unit 23, it identifies the round-trip transmission time of the optical signal between the optical communication device to which the virtual address is assigned. Furthermore, the virtual network control unit 27 determines whether or not the power of the optical signal is within a preset range as a determination result associated with the virtual address.

[0057] When the virtual network control unit 27 determines that the power of the optical signal is within a preset range as a result of the determination associated with the virtual address, the virtual network control unit 27 generates an ICMP Echo reply with the virtual address set as the destination set as the source. The virtual network control unit 27 outputs the generated ICMP Echo reply to the control packet processing unit 28. When the sender of the ICMP Echo is the user device 60, the virtual network control unit 27 sets the destination of the ICMP Echo reply to the user device 60. Also, when the virtual network control unit 27 determines that the power of the optical signal is not within a preset range as a result of the determination associated with the virtual address, the virtual network control unit 27 does not generate an ICMP Echo reply. In other words, when the virtual network control unit 27 determines that the power of the optical signal is not within a preset range, the virtual network control unit 27 does not respond to the user device 60 with an ICMP Echo reply.

[0058] When outputting the ICMP Echo reply to the control packet processing unit 28, the virtual network control unit 27 may output the ICMP Echo reply to the control packet processing unit 28 at a timing when a specified round-trip transmission time has elapsed since the input / output processing unit 24 received the ICMP Echo. Alternatively, when the input / output processing unit 24 transmits the ICMP Echo reply to the user device 60, the virtual network control unit 27 may output the ICMP Echo reply to the control packet processing unit 28 so that the round-trip transmission time has elapsed since the input / output processing unit 24 received the ICMP Echo.

[0059] 6, a process flow of the router 20 when the user equipment 60 uses Ping as a tool for measuring a round-trip transmission time to the optical communication device 40 will be described. Ping is used to measure the RTT (Round Trip Time) from sending an ICMP Echo to receiving an ICMP Echo reply.

[0060] First, the input / output processing unit 24 receives a packet from the user device 60 (S11). Next, the packet forwarding unit 23 determines whether the received packet is an ICMP Echo (S12). When the packet forwarding unit 23 determines in step S12 that it has received an ICMP Echo, the virtual network control unit 27 determines whether the destination of the ICMP Echo is a virtual address (S13).

[0061] In step S13, if the virtual network control unit 27 determines that the destination of the ICMP Echo is a virtual address, it determines whether the power of the optical signal associated with the virtual address is within a preset range, that is, whether it is equal to or greater than a threshold value (S14).

[0062] When the virtual network control unit 27 determines in step S14 that the power of the optical signal associated with the virtual address is equal to or greater than the threshold, the virtual network control unit 27 generates an ICMP Echo reply, and the input / output processing unit 24 transmits the ICMP Echo reply to the user device 60 (S15). Here, the virtual network control unit 27 determines the output timing of the ICMP Echo reply based on the round-trip transmission time managed in association with the virtual address. For example, the virtual network control unit 27 may output the ICMP Echo reply to the control packet processing unit 28 at the timing when the round-trip transmission time has elapsed. Alternatively, when the input / output processing unit 24 transmits the ICMP Echo reply to the user device 60, the virtual network control unit 27 may output the ICMP Echo reply to the control packet processing unit 28 so that the round-trip transmission time has elapsed since the input / output processing unit 24 received the ICMP Echo. The virtual network control unit 27 sets the source address of the ICMP Echo reply to the virtual address.

[0063] In step S12, if the packet forwarding unit 23 determines that the received packet is not an ICMP Echo, it outputs the received packet to the frame processing unit 22, and the optical signal processing unit 21 transmits an optical signal including the packet to the optical communication network (S16).

[0064] In step S13, if the virtual network control unit 27 determines that the destination of the ICMP Echo is not a virtual address, it outputs the packet to the optical signal processing unit 21 via the packet forwarding unit 23. Furthermore, the optical signal processing unit 21 transmits an optical signal including the packet to the optical communication network (S16).

[0065] In step S14, if the virtual network control unit 27 determines that the power of the optical signal associated with the virtual address is below the threshold, it does not respond with an ICMP Echo reply to the ICMP Echo. In other words, in step S14, if the virtual network control unit 27 determines that the power of the optical signal associated with the virtual address is below the threshold, the process ends without executing the process in step S15.

[0066] As described above, the router 20 responds with an ICMP Echo reply to an ICMP Echo in which a virtual address assigned to the optical communication device 40 or 50 is set. Furthermore, the router 20 responds with an ICMP Echo reply based on the round-trip transmission time between the router 20 and the optical communication device 40 or 50. As a result, the user equipment 60 can respond with an ICMP Echo replay after a time substantially similar to that when an ICMP Echo is transmitted to the optical communication device 40 or 50 and an ICMP Echo reply transmitted from the optical communication device 40 or 50 is received has elapsed.

[0067] Furthermore, the router 20 does not respond with an ICMP Echo reply when the destination of the ICMP Echo is a virtual address assigned to the optical communication device 40 and the power of the optical signal in the optical communication device 40 is below a threshold. This allows the user equipment 60 to detect the occurrence of a fault between the router 20 and the optical communication device 40 or to estimate the occurrence of a fault.

[0068] In the second embodiment, the operation using ICMP Echo has been mainly described, however, continuity check and delay check that perform request / response operations similar to ICMP Echo, such as Ethernet (registered trademark) OAM (which may also be referred to as Ether OAM) or MPLS OAM, may also be used.

[0069] In addition, in the communication system of Fig. 3, a configuration example in which two optical communication devices exist in the optical communication network between routers has been described, but the number of optical communication devices is not limited to two. For example, as shown in Fig. 7, the number of optical communication devices may be generalized to n (n is an integer equal to or greater than 1). Fig. 7 shows a configuration example in which optical communication devices 40_1 to 40_n exist. It is assumed that virtual addresses V1 to Vn are assigned to the optical communication devices 40_1 to 40_n, respectively.

[0070] When laying an optical fiber, the transmission time di (i=1 to n) in the optical fiber section is measured. Let di represent the transmission time in the optical fiber section between the optical communication device 40_i-1 and the optical communication device 40_i. In this case, the round-trip transmission time Di between the router 20 and the optical communication device 40_i is expressed by the following formula (1).

[0071] Formula (1) TIFF0007622877000001.tif1319

[0072] The router 20 records information regarding the round-trip transmission time to each of the optical communication devices 40_1 to 40_n.

[0073] (Embodiment 3) Next, a configuration example of a communication system according to the third embodiment will be described with reference to Fig. 8. In the communication system of Fig. 8, a measuring instrument 80 is disposed between the router 20 and the router 30. Furthermore, the measuring instrument 80 may be disposed in a position close to the router 20. The measuring instrument 80 is used to detect whether or not a fault has occurred in the optical communication network by using an optical pulse signal.

[0074] Next, a configuration example of the measuring instrument 80 according to the third embodiment will be described with reference to Fig. 9. The measuring instrument 80 may be a computer device that operates when a processor executes a program stored in a memory.

[0075] The measuring instrument 80 has a connector 81, a connector 82, a coupler 83, and a virtual measurement unit 84. The connectors 81, 82, and coupler 83 are similar to the connectors 41, 42, and coupler 43 in Fig. 4, so detailed description will be omitted. The connector 81 connects to an optical fiber between the router 30. The connector 82 connects to an optical fiber between the router 20.

[0076] The virtual measurement unit 84 has a control unit 85 and an optical pulse test unit 86. The optical pulse test unit 86 may be called, for example, an OTDR (Optical Time Domain Reflectometer). The optical pulse test unit 86 is used, for example, to detect a break in an optical fiber. The optical pulse test unit 86 detects a fault occurring in the optical fiber by transmitting an optical pulse signal and observing the reflection of the optical pulse signal, and further identifies the fault location. The fault location may be identified, for example, by the distance from the measuring instrument 80. The optical pulse test unit 86 transmits an optical pulse signal in the direction of the router 30 via the connector 81. That is, the optical pulse test unit 86 is used to determine whether or not a fault has occurred in the optical fiber laid between the measuring instrument 80 and the router 30.

[0077] The optical pulse test unit 86 may transmit an optical pulse signal periodically, or may transmit an optical pulse signal at any timing in response to an instruction from an administrator or the like who operates the measuring instrument 80. After transmitting an optical pulse signal, the optical pulse test unit 86 determines whether or not a fault has occurred in the optical communication network by observing the reflection of the optical pulse signal. The optical pulse test unit 86 outputs the determination result to the control unit 85. The control unit 85 transmits the determination result to the virtual network control unit 27 of the router 20. The determination result includes information indicating whether or not a fault has occurred, and, if a fault has occurred, information specifying the location of the fault. The control unit 85 may transmit the determination result to the router 20 via the connector 82, or may transmit the determination result to the router 20 via the maintenance network.

[0078] The router 20 uses the determination result received from the measuring instrument 80 to determine whether or not to respond with an ICMP Echo reply to the ICMP Echo received from the user device 60. Here, the virtual addresses assigned to the virtual devices on the optical communication network will be described with reference to FIG. 10. As shown in FIG. 10, it is assumed that a virtual device to which a virtual address VA_1 is assigned, a virtual device to which a virtual address VA_2 is assigned, and a virtual device to which a virtual address VA_3 is assigned exist between the router 30 and the measuring instrument 80. Although the virtual devices are not actually placed as physical devices, the router 20 notifies the user device 60 of the virtual addresses VA_1, VA_2, and VA_3 using a route exchange protocol. Alternatively, the user device 60 may be notified of configuration information indicating a network configuration in which devices to which the virtual addresses VA_1, VA_2, and VA_3 are assigned exist between the router 20 and the router 30. As a result, the user device 60 recognizes that between the router 20 and the router 30, devices to which the virtual addresses VA_1, VA_2, and VA_3 are assigned actually exist.

[0079] For example, in order to verify reachability to the virtual address VA_1, the user device 60 transmits an ICMP Echo with the virtual address VA_1 set to the router 20. In order to verify reachability to the virtual address VA_2 or the virtual address VA_3, the user device 60 may transmit an ICMP Echo with the virtual address VA_2 or the virtual address VA_3 set to the router 20.

[0080] Assume that the router 20 has been notified of the determination result received from the measuring instrument 80 that a fault has occurred between a virtual device to which virtual address VA_1 is assigned and a virtual device to which virtual address VA_2 is assigned. In this case, the router 20 does not respond with an ICMP Echo reply to an ICMP Echo in which virtual address VA_1 is set. On the other hand, the router 20 transmits an ICMP Echo reply to an ICMP Echo in which virtual address VA_2 or virtual address VA_3 is set. When transmitting an ICMP Echo replay to an ICMP Echo in which virtual address VA_2 or virtual address VA_3 is set, the router 20 determines the timing of transmitting the ICMP Echo replay in accordance with the round-trip transmission time between the router 20 and the virtual device.

[0081] The user device 60 can estimate the location of the failure depending on whether or not an ICMP Echo reply is received from the router 20. For example, assume that the user device 60 does not receive an ICMP Echo reply to an ICMP Echo that sets a virtual address VA_1, but receives an ICMP Echo reply to an ICMP Echo that sets a virtual address VA_2. In this case, the user device 60 can estimate that the failure has occurred between the location of the virtual device to which the virtual address VA_1 is assigned and the location of the virtual device to which the virtual address VA_2 is assigned.

[0082] As described above, the router 20 can detect the location of a fault in an optical fiber as a fault in a virtual device-to-device link. Furthermore, the user device 60 can detect the location of the fault according to the result of receiving the ICMP Echo reply.

[0083] (Embodiment 4) Next, a configuration example of a communication network according to the fourth embodiment will be described with reference to Fig. 11. Fig. 11 shows a configuration in which optical switches 91 to 94 are used instead of the optical communication devices 40 and 50 in Fig. 3. Fig. 11 shows a configuration in which the optical switch 91 is connected to the router 20, the optical switch 92, and the optical switch 94 via optical fibers, and the optical switch 92 is connected to the optical switch 91 and the optical switch 93 via optical fibers. Furthermore, Fig. 11 shows a configuration in which the optical switch 93 is connected to the optical switch 92 and the optical switch 94 via optical fibers, and the optical switch 94 is connected to the router 30, the optical switch 93, and the optical switch 91 via optical fibers. It is assumed that virtual addresses are assigned to the optical switches 91 to 94.

[0084] Next, a configuration example of the optical switch 91 will be described with reference to Fig. 12. The optical switches 92 to 94 have the same configuration as the optical switch 91, and therefore detailed description thereof will be omitted.

[0085] The optical switch 91 has connectors 101 to 104, a switch 105, and a virtual device unit 106. The switch 105 outputs optical signals received from the connectors 101 to 104 to either the connectors 101 to 104 or the optical switch manager 108. Furthermore, the optical switch 91 outputs the detection states of the optical signals in the connectors 101 to 104 to the optical switch manager 108. In other words, the optical switch 91 outputs the continuity states of the connectors 101 to 104 to the optical switch manager 108. That is, the switch 105 judges whether or not the optical signals can be detected in the connectors 101 to 104, and outputs the judgment result to the optical switch manager 108.

[0086] The optical switch manager 108 determines whether or not a fault has occurred in the optical fiber connected to each connector, based on the determination result received from the switch 105. For example, the optical switch manager 108 may determine that a fault has occurred in the optical fiber connected to a connector that cannot detect an optical signal.

[0087] The control unit 107 transmits the determination result in the optical switch management unit 108 to the router 20 and the router 30. The determination result includes information regarding the optical fiber connected to which connector the fault has occurred in. The control unit 107 may transmit the determination result to the router 20 and the router 30 via, for example, a maintenance network.

[0088] The router 20 identifies which section of the optical fiber has a fault, based on the determination results received from the optical switches 91-94. Furthermore, when the router 20 receives an ICMP Echo with a virtual address set from the user device 60, if the virtual address of an optical switch that communicates through the optical fiber in which the fault has occurred is set in the ICMP Echo, the router 20 does not respond with an ICMP Echo reply. If the virtual address of an optical switch that does not need to communicate through the optical fiber in which the fault has occurred is set in the ICMP Echo, the router 20 responds with an ICMP Echo reply.

[0089] As described above, even if the route is branched by an optical switch that constitutes the optical communication network, the router 20 and the router 30 can identify the location of a fault that has occurred in the optical communication network. Furthermore, the router 20 can control whether or not to respond with an ICMP Echo reply to an ICMP Echo received from the user device 60 depending on the fault occurrence state. As a result, an external device such as the user device 60 can detect the location of a fault that has occurred in the optical communication network.

[0090] Fig. 13 is a block diagram showing a configuration example of a communication apparatus 10, an optical communication device 40, and an optical communication device 50 (hereinafter referred to as communication apparatuses 10, etc.). Referring to Fig. 13, the communication apparatuses 10, etc. include a network interface 1201, a processor 1202, and a memory 1203. The network interface 1201 may be used to communicate with a network node. The network interface 1201 may include, for example, a network interface card (NIC) that complies with the IEEE 802.3 series. IEEE stands for Institute of Electrical and Electronics Engineers.

[0091] The processor 1202 reads out and executes software (computer programs) from the memory 1203 to perform the processing of the communication device 10 and the like described using the flowcharts in the above-mentioned embodiments. The processor 1202 may be, for example, a microprocessor, an MPU, or a CPU. The processor 1202 may include multiple processors.

[0092] The memory 1203 is configured by a combination of volatile memory and non-volatile memory. The memory 1203 may include storage located away from the processor 1202. In this case, the processor 1202 may access the memory 1203 via an I / O (Input / Output) interface (not shown).

[0093] 13, the memory 1203 is used to store software modules. The processor 1202 reads out and executes the software modules from the memory 1203 to perform the processing of the communication device 10 and the like described in the above-mentioned embodiment.

[0094] As described with reference to FIG. 13, each of the processors of the communication device 10 in the above-described embodiment executes one or more programs including a set of instructions for causing a computer to execute the algorithm described with reference to the drawings.

[0095] In the above examples, the program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, the computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray® disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, the transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0096] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0097] 10. Communications Equipment 11 Communications Department 12 Management Department 13 Control section 20 Router 21 Optical signal processing section 22 Frame Processing Section 23 Packet forwarding unit 24 Input / Output Processing Section 25 Frame Processing Section 26 Virtual Router Section 27 Virtual Network Control Section 28 Control packet processing unit 30 Router 40 Optical Communication Devices 41 Connector 42 Connector 43 Coupler 44 Virtual Device Section 45 Virtual Device Control Unit 46 Optical Power Meter 50 Optical communication devices 60 User device 70 External device 80 Measuring Instruments 81 Connector 82 Connector 83 Coupler 84 Virtual Measurement Section 85 Control Unit 86 Optical Pulse Test Section 91 Optical Switch 92 Optical Switch 93 Optical Switch 94 Optical Switch 101 Connector 102 Connector 103 Connector 104 Connector 105 Switch 106 Virtual Device Section 107 Control Unit 108 Optical Switch Management Unit

Claims

1. a communication unit that connects to an optical communication network that transmits optical signals; a management unit that manages a transmission time of the optical signal between a virtual device on the optical communication network and the communication unit, and identification information of the virtual device in association with each other; A communication device comprising: a control unit that, when receiving a request message requesting the transmission time of the optical signal between the virtual device and the communication unit, responds to the request message with a response message indicating the transmission time managed in association with identification information of the virtual device.

2. The management unit Using virtual address information assigned to the virtual device as identification information of the virtual device, The control unit is 2. The communication device according to claim 1, wherein when the request message including the virtual address information is received, the communication device responds to the request message with a response message indicating the transmission time managed in association with the virtual address information.

3. The control unit is The communication device according to claim 2 , wherein the virtual address information included in the request message is set as a source address of the response message.

4. The control unit is A communication device as described in any one of claims 1 to 3, wherein when a request message requesting the transmission time of the optical signal between the virtual device and the communication unit is received, the response message is responded to after the transmission time has elapsed since receiving the request message.

5. The control unit is The communication device according to claim 1 , wherein when a failure occurs in the virtual device or in a section between the virtual device and the communication unit, the communication device does not respond to the request message.

6. 6. The communication device of claim 5, wherein the fault is detected by using reflections of optical pulse signals.

7. The control unit is A communication device as described in any one of claims 1 to 6, which determines whether an incoming message received from an external device corresponds to the request message, and if it is determined that the incoming message corresponds to the request message, responds with the response message to the external device, and if it is determined that the incoming message does not correspond to the request message, outputs the incoming message to the optical communication network.

8. managing a transmission time of an optical signal between a virtual device and a communication device on an optical communication network that transmits the optical signal in association with identification information of the virtual device; A communication method executed in a communication device, in which, when a request message requesting a transmission time of the optical signal between the virtual device and the communication device is received, a response message indicating the transmission time managed in association with identification information of the virtual device is responded to the request message.

9. managing a transmission time of an optical signal between a virtual device and a communication device on an optical communication network that transmits the optical signal in association with identification information of the virtual device; A program that causes a computer to respond to a request message requesting the transmission time of the optical signal between the virtual device and the communication device with a response message indicating the transmission time that is managed in association with the identification information of the virtual device.

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