OLT of PON system, redundant communication device, the PON system, band control method, and program

Abstract

To contribute to stable communication while maintaining effective use of a band in a PON system.SOLUTION: In an OLT of a PON system, a communication device comprises: a terminal line switch control part that outputs an alarm notification in the case where a traffic amount between a plurality of ONUs to be housed is detected, and a total traffic amount is larger than a predetermined first threshold value; and a communication device authentication part that outputs a switch instruction for switching a connection destination to a mobile line from a predetermined line to a first communication device that is connected to an alternative available UNU in a predetermined line via an alternative available ONU as at least one ONU of the plurality of ONUs when the alarm notification is output. The plurality of ONUs is connected to the other end of an optical fiber line branched by an optical coupler inserted into a middle of the optical fiber line to which each OLT is connected to one end. In the alternative available ONU, the communication device to be connected is the first communication device, and the first communication device is a communication device that can be connected with the predetermined line and the mobile line.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an OLT in a PON system, a redundant communication device, a PON system, a bandwidth control method, and a program. [Background technology]

[0002] With the spread of optical fiber lines, there is a demand for services that support faster and larger capacity communications. One technology for achieving faster and larger capacity communications is the Passive Optical Network (PON) system, which branches optical signals by branching optical fiber lines and introduces the branched optical signals to each subscriber's home (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-184006 A Summary of the Invention [Problem to be solved by the invention]

[0004] The following analysis has been provided by the inventors of the present invention.

[0005] The PON system is a type of optical access line that connects a communication station and an end user with an optical fiber cable, and is a system that realizes P2MP (Point to Multi Point) communication. In the PON system, the optical fiber cable transmission path is branched by an optical coupler installed along the way, and time division multiplexing (TDM) makes it possible for one device on the communication station side to accommodate multiple devices on the end user side.

[0006] 11, the PON system 900 includes an OLT (Optical Line Terminal) 920, a plurality of ONUs (Optical Network Units) 930, an optical fiber cable 960, and an optical coupler 969. Each ONU 930 is connected to a communication device 940 via a wired cable 970.

[0007] Communications (PON communications) within the PON system 900 are performed by a time division multiplexing communication method (a communication method in which each ONU is assigned to a time slot) for both upstream and downstream. The time slots are dynamically allocated, for example, by referring to the buffer information of the ONU 930. This function is called a DBA (Dynamic Bandwidth Allocation) function. The DBA function is a function that realizes efficient upstream bandwidth without generating unused bandwidth by appropriately switching the allocated bandwidth according to the traffic status of the upstream communication flowing through each ONU 930.

[0008] In this case, the limited bandwidth must be shared between the OLT 920 and each connected ONU 930. In this diagram, a configuration in which four ONUs 930 are connected is shown as an example, but considering the economic advantages of optical fiber networks in the access area, it is assumed that four or more ONUs 930 will be connected.

[0009] As the number of ONUs 930 connected to the OLT 920 increases, the bandwidth allocated to each ONU 930 decreases. Therefore, in the PON system 900, if a specific ONU 930 occupies the bandwidth, it may not be possible to ensure communication stability for the other ONUs 930.

[0010] The present invention has been made in consideration of the above circumstances, and has an object to provide a technique that contributes to the stability of communication between an OLT and an ONU in a PON system while maintaining efficient use of bandwidth. [Means for solving the problem]

[0011] According to a first aspect of the present disclosure, An OLT (Optical Line Terminal) of a PON (Passive Optical Network) system, a terminal line switching control unit that detects traffic volume between each of a plurality of optical subscriber devices (ONUs) accommodated in the network and outputs an alarm notification when a total traffic volume between the ONUs and each of the optical subscriber devices is greater than a first threshold value; An OLT of a PON system is provided which, when the alarm notification is output, outputs a switching instruction, which is an instruction to switch the connection destination from the specified line to a mobile line, to a first communication device connected to a replaceable ONU via a specified line via a replaceable ONU, which is at least one of the multiple ONUs. The plurality of ONUs are each connected to one end of an optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line to which the OLT is connected, and the other end of the optical fiber line branched by the optical coupler is connected, The replaceable ONU is the ONU to which a communication device connected is the first communication device, The first communication device is provided with an OLT, which is a communication device connectable to the predetermined line and the mobile line.

[0012] According to a second aspect of the present disclosure, a WAN port section for connecting to an ONU (Optical Network Unit) via a predetermined line; A mobile line WAN (Wide Area Network) module that connects to a mobile line; a connection control unit that switches a connection destination between the predetermined line and the mobile line, The connection control unit is When the ONU is connected, a message is sent via the ONU to the OLT (Optical Line Terminal), which is the central office side device of the PON system that accommodates the ONU. A redundant communication device is provided which switches the connection from the specified line to the mobile line when a switching instruction is received from the OLT via the ONU to which it is connected, which is an instruction to switch the connection destination from the specified line to the mobile line.

[0013] According to a third aspect of the present disclosure, An OLT (Optical Line Terminal) is a central office device connected to one end of the optical fiber line. A PON (Passive Optical Network) system is provided, comprising: a plurality of ONUs (Optical Network Units), which are optical subscriber devices, each connected to the other end of the optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line. At least one of the plurality of ONUs, which is a replaceable ONU, is a communication device connected to the replaceable ONU via a predetermined line, which is a first communication device connectable to the predetermined line and a mobile line; The OLT is a terminal line switching control unit that detects a traffic volume between each of the plurality of ONUs, and outputs an alarm notification when a total traffic volume between the plurality of ONUs is greater than a first threshold value; There is provided a system including a communication equipment authentication unit that, when the alarm notification is output, outputs, via the replaceable ONU, an instruction to the first communication equipment to switch a connection destination from the specified line to the mobile line.

[0014] According to a fourth aspect of the present invention, A bandwidth control method by an OLT (Optical Line Terminal) of a PON (Passive Optical Network) system, A traffic detection step of detecting the amount of traffic between the OLT and each of a plurality of ONUs (Optical Network Units) that are optical subscriber devices accommodated in the OLT; a determining step of outputting an alarm notification when a total traffic volume, which is the sum of the detected traffic volumes, is greater than a predetermined first threshold value; When the alarm notification is output, a switching instruction step is provided in which a switching instruction is output to a first communication device connected to the ONU, which is at least one of the multiple ONUs, via a replaceable ONU, to switch the connection destination from a specified line to a mobile line. The plurality of ONUs are each connected to one end of an optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line to which the ONU is connected, and the other end of the optical fiber line branched by the optical coupler is connected, The replaceable ONU is the ONU to which a communication device is connected, the first communication device being the ONU; The first communication device is a communication device connectable to the specified line and the mobile line, and a bandwidth control method is provided.

[0015] According to a fifth aspect of the present invention, The computer of the OLT (Optical Line Terminal) of the PON (Passive Optical Network) system a traffic detection step for detecting the amount of traffic between each of a plurality of ONUs (Optical Network Units) that are optical subscriber devices accommodated in the OLT, the ONUs being connected to the other ends of optical fiber lines branched by an optical coupler inserted in the middle of the optical fiber line to which the OLT is connected at one end; a determination step of outputting an alarm notification when a total traffic volume, which is the sum of the detected traffic volumes, is greater than a first threshold value; When the alarm notification is output, a program is provided for executing a switching instruction procedure, which outputs a switching instruction to at least one ONU of the multiple ONUs, which is a replaceable ONU and has a connected communication device that is a first communication device that can be connected to a specified line and a mobile line, via the ONU, to the first communication device, which is an instruction to switch the connection destination from the specified line to the mobile line.

[0016] According to a sixth aspect of the present invention, A redundant communication device connected to an ONU (Optical Network Unit) of a PON (Passive Optical Network) system via a predetermined line, a WAN port unit connected to the ONU via the predetermined line; A mobile line WAN module unit for connecting to a mobile line, and a computer of a redundant communication device having the mobile line WAN module unit. a transmission procedure for transmitting a message via the ONU to an OLT (Optical Line Terminal) that accommodates the ONU when the ONU is connected to the ONU; When a switching instruction is received from the OLT via the connected ONU, which is an instruction to switch the connection destination from the specified line to the mobile line, a switching procedure for switching the connection destination from the specified line to the mobile line is provided, and a program for executing the switching procedure is provided.

[0017] These programs can be recorded on a computer-readable storage medium. The storage medium can be a non-transitory medium such as a semiconductor memory, a hard disk, a magnetic recording medium, an optical recording medium, etc. The present invention can also be embodied as a computer program product. Effect of the Invention

[0018] According to the present invention, in a PON system, it is possible to contribute to stable communication while maintaining efficient use of the band. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2A is an overall configuration diagram showing an example of the overall configuration of a PON system according to the present disclosure, and FIG. 2B is a functional block diagram showing an example of the functional configuration of an OLT according to the present disclosure. [Diagram 2] 1 is an overall configuration diagram showing an example of the overall configuration of a PON system according to the present disclosure. [Diagram 3] 1A to 1C are functional block diagrams showing examples of functional configurations of an OLT, an ONU, and a WAN redundant communication device according to the present disclosure, respectively. [Figure 4] 1 is an explanatory diagram for explaining an example of an ONU management table according to the present disclosure. [Diagram 5] 13 is a flowchart of an example of a device recognition process according to the present disclosure. [Figure 6] 13 is a flowchart of an example of a device recognition process according to the present disclosure. [Figure 7] 1 is a flowchart of an example of a traffic monitoring process according to the present disclosure. [Figure 8] FIG. 2 is a functional block diagram showing an example of a functional configuration of an OLT according to the present disclosure. [Figure 9] 13 is a flowchart of an example of a process at the time of abnormal disconnection according to the present disclosure. [Figure 10] 2 is a hardware configuration diagram showing an example of a hardware configuration of an OLT, an ONU, and a WAN redundant communication device according to the present disclosure. FIG. [Figure 11] FIG. 1 is an overall configuration diagram of a conventional PON system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] An outline of one embodiment of the present invention (hereinafter, referred to as the present embodiment) will be described below with reference to the drawings. Note that the reference symbols in the drawings are given to each element for convenience as an example to aid understanding, and are not intended to limit the present invention to the illustrated form. Furthermore, the connection lines between blocks in the drawings and the like referred to in the following description include both bidirectional and unidirectional lines. Unidirectional arrows are used to diagrammatically indicate the flow of the main signal (data), and do not exclude bidirectionality.

[0021] In addition, although there are ports and interfaces at the connection points of input and output of each block in the figure, they are not shown in the figure. In the following explanation, "A and / or B" means A or B, or A and B.

[0022] <<First embodiment>> An outline of this embodiment will be described.

[0023] In this embodiment, in a PON (Passive Optical Network) system in which a WAN (Wide Area Network) redundant communication device (a communication device that can be connected to either a specified line (e.g., a wired line) or a mobile line) is connected to an ONU (Optical Network Unit), when a state occurs in which a specific ONU occupies a bandwidth, the WAN redundant communication device is switched from wired communication using a specified line with an OLT (Optical Line Terminal) to wireless communication using a mobile line in order to ensure communication stability for ONUs to which the WAN redundant communication device is not connected.

[0024] The configuration of this embodiment that achieves this will be described below.

[0025] 1(a) is a diagram showing the overall configuration of a PON system 100 according to this embodiment. As shown in the figure, the PON system 100 constitutes an optical subscriber access network.

[0026] The PON system 100 of this embodiment includes an OLT device (hereinafter, OLT) 200 which is a communication device (station side device) on the provider side, and a plurality of ONU devices (hereinafter, ONU) 301, 302, 303, and 304 which are communication devices (optical subscriber devices) on the subscriber side.

[0027] In this example, the PON system 100 includes four ONUs. However, the number of ONUs is not limited to this. In addition, when there is no particular need to distinguish between them, they will be represented by ONU 300.

[0028] The OLT 200 is connected to one end of an optical fiber line (hereinafter, optical fiber) 600, which is an optical communication line. The other end of the optical fiber 600 is connected to the ONU 300. An optical coupler 690 for branching / gathering the optical fiber 600 is connected midway along the optical fiber 600. The optical coupler 690 branches one optical transmission line (optical fiber 600) into multiple lines. The other ends of the branched optical fibers 601, 602, 603, and 604 are connected to the ONUs 301, 302, 303, and 304, respectively. The optical coupler 690 for multiplexing / demultiplexing optical signals is installed between the OLT 200 and the ONUs 300, so that multiple ONUs 300 are connected to one OLT 200.

[0029] To each of the ONUs 301, 302, 303, for example, communication devices 401, 402, 403 are connected via wired cables 701, 702, 703. To the ONU (replaceable ONU) 304, for example, a WAN redundant communication device (first communication device) 500 is connected via a wired cable 704, and further, a communication device 404 is connected via a wired cable 800.

[0030] When there is no particular need to distinguish between them, the wired cables 701 to 704 are represented by the wired cable 700. Moreover, the communication devices 401 to 404 are represented by the communication device 400.

[0031] In the example of the figure, WAN redundant communication equipment 500 is connected to ONU 304, but it is sufficient that WAN redundant communication equipment 500 is connected to at least one of the multiple ONUs 300 in PON system 100. As described above, WAN redundant communication equipment 500 is a communication equipment that can be connected to a wired line and a mobile line. That is, WAN redundant communication equipment 500 is an equipment that can switch a connection to a WAN line between, for example, a wired cable 700 and a mobile line.

[0032] In this embodiment, as described above, when a state occurs in which a specific ONU 300 occupies a bandwidth, the connection of the WAN redundant communication device 500 is switched from a wired line to a mobile line.

[0033] 1(b) shows functional blocks of the OLT 200 of this embodiment that realizes this. As shown in this figure, the OLT 200 of this embodiment includes a terminal line switching control unit 210, a communication device authentication unit 220, and a PON termination unit 230.

[0034] The terminal line switching control unit 210 detects the traffic volume between each of the multiple ONUs 300 accommodated in the OLT 200. Then, it determines whether the total traffic volume is greater than a predetermined threshold (first threshold). If it is determined that the total traffic volume is greater, it outputs an alarm notification to the communication equipment authentication unit 220.

[0035] When the communication device authentication unit 220 receives the alarm notification, it outputs a WAN line switching instruction via the replaceable ONU 304. The output destination is the WAN redundant communication device 500 connected to the replaceable ONU 304 via a wired cable 700. The WAN line switching instruction is an instruction to switch the connection from the wired line to a mobile line.

[0036] The PON termination unit 230 performs data communication with a network higher than the OLT 200, establishes links with the ONUs 300 accommodated in the OLT 200, identifies ONUs 300 that have been linked up / down, performs data communication with the ONUs 300, controls the entire OLT 200, and so on.

[0037] As described above, in the PON system 100 of this embodiment, when the traffic volume exceeds a predetermined threshold, the WAN redundant communication equipment 500 is disconnected from the PON system 100, thereby making it possible to ensure communication stability for other ONUs to which the WAN redundant communication equipment 500 is not connected.

[0038] <<Second embodiment>> Next, a second embodiment to which the present invention is applied will be described.

[0039] The overall configuration of a PON system 100a of this embodiment is shown in Fig. 2. The overall configuration of the PON system 100a is basically the same as that of the PON system 100 of the first embodiment shown in Fig. 1(a). However, instead of the OLT 200, an OLT 200a is provided.

[0040] In the PON system 100a of this embodiment, bandwidth is dynamically allocated by DBA (Dynamic Bandwidth Allocation). Therefore, similar to the first embodiment, when a specific ONU 300 occupies a bandwidth, communication stability of other ONUs 300 cannot be guaranteed.

[0041] In this embodiment as well, the OLT 200a monitors the traffic volume between the ONUs 300, and when a state occurs in which a specific ONU 300 occupies the bandwidth, the connection of the WAN redundant communication device 500 is switched. Here, the connection is switched from wired communication using a wired line with the OLT 200a to wireless communication using a mobile line with the WAN. This is to ensure communication stability for the ONUs 300 to which the WAN redundant communication device 500 is not connected.

[0042] A PON system 100a according to the present embodiment that realizes this will be specifically described below. The following description of the present embodiment will focus on the configuration that differs from the first embodiment.

[0043] The OLT 200a is a central office device that accommodates a plurality of ONUs 300. The OLT 200a uses a time division multiplexing (TDM) technique to accommodate a plurality of ONUs 300. The OLT 200a of this embodiment has a DBA function that dynamically allocates a bandwidth for upstream communication from the ONUs 300 to the OLT 200a according to the amount of traffic. The OLT 200a receives an optical signal transmitted from the ONUs 300 and transfers it to a higher-level device or a higher-level network (e.g., the Internet, etc.). The OLT 200a also receives a signal from the higher-level device or the higher-level network and transfers it to each ONU 300. The OLT 200a plays a role in controlling and monitoring the entire PON system 100a and the ONUs 300. The OLT 200a is connected to the ONUs 301 to 304 via an optical fiber 600, an optical coupler 690, and optical fibers 601 to 604.

[0044] The ONU300 is an optical subscriber device. It provides optical subscribers with a line for accessing a network such as the Internet. The ONU300 receives an optical signal transmitted from the OLT200a and converts it into an electrical signal. The ONU300 then transfers the converted electrical signal to a connected device (e.g., a communication device, a PC, etc.). The ONU300 also receives an electrical signal transmitted from a connected device and converts it into an optical signal. The ONU300 then transfers the converted optical signal to the OLT200a.

[0045] The communication device 400 is a router, a switching hub, a personal computer, etc. The WAN redundant communication device 500 is a device that selectively enables a WAN connection between a wired connection via a PON system and a wireless connection via a mobile line such as LTE (Long Term Evolution). The WAN redundant communication device 500 is connected to the communication device 404 via a wired cable 800.

[0046] 3(a) is a functional block diagram of the OLT 200a. As shown in this figure, the OLT 200a includes a terminal line switching control unit 210, a communication device authentication unit 220, and a PON termination unit 230. The OLT 200a also holds an ONU management table 250 for managing the ONUs 300 connected thereto. The OLT 200a may further hold a threshold value 260. The threshold value 260 is used to determine whether or not the traffic of the PON communication is congested, as will be described later.

[0047] 3(b) is a functional block diagram of the ONU 300. As shown in this figure, the ONU 300 includes a PON termination unit 310 and a UNI (User-Network Interface) termination unit 320.

[0048] 3(c) is a functional block diagram of WAN redundant communications device 500. As shown in this figure, WAN redundant communications device 500 includes a WAN port 510, a WAN connection control unit 520, and a LAN connection port unit 530. WAN port 510 includes a wired WAN port unit 511 and a mobile line WAN module unit 512.

[0049] The functions of each device will be described below.

[0050] [OLT] The PON termination unit 230 basically has the same functions as the configuration of the same name in the first embodiment. That is, the PON termination unit 230 performs data communication with a network higher than the OLT 200a, establishment of a link with the ONU 300 accommodated in the OLT 200a, identification of individual information of the accommodated ONU 300, data communication with the accommodated ONU 300, control of the entire OLT 200a, etc.

[0051] The communication device authentication unit 220 basically has the same function as the configuration of the same name in the first embodiment. That is, the communication device authentication unit 220 manages individual information of the ONU 300 connected to the OLT 200a (accommodated by the OLT 200a). When the ONU 300 is newly connected to the OLT 200a, the communication device authentication unit 220 acquires individual information of the ONU 300 via the PON termination unit 230. The acquired individual information is then registered in the ONU management table 250. When the ONU 300 disconnects from the OLT 200a, the communication device authentication unit 220 may acquire individual information of the ONU 300 via the PON termination unit 230 and delete (erase) the corresponding data (record) in the ONU management table 250. Note that, as described later, when the connection with the OLT 200a is disconnected in accordance with a switching instruction, the record itself may be left.

[0052] Furthermore, the communication device authentication unit 220 manages the link state (link status) of the UNI termination unit 320 of the ONU 300. The communication device authentication unit 220 receives information indicating the link status of the UNI termination unit 320 (hereinafter simply referred to as link status) transmitted from the ONU 300. The received link status is registered in the ONU management table 250 in association with the source ONU 300. The link status is information indicating whether or not any device is connected to the UNI termination unit 320. Hereinafter, a connected state is referred to as a "link up" state, and a non-connected state is referred to as a "link down" state.

[0053] Furthermore, when the device connected to UNI termination unit 320 is WAN redundant communication device 500, communication device authentication unit 220 receives a message indicating that the device is WAN redundant communication device (WAN redundant communication device notification message) via PON termination unit 230. Note that the WAN redundant communication device notification message is transmitted from WAN connection control unit 520 of WAN redundant communication device 500.

[0054] This allows the unit to know whether the device connected to the UNI termination unit 320 of the ONU 300 is the communication device 400 or the WAN redundant communication device 500. This information is also registered in the ONU management table 250 in association with the ONU 300. The communication device authentication unit 220 may have a function of notifying the WAN connection control unit 520 of the WAN redundant communication device 500 that registration in the ONU management table 250 for management has been completed.

[0055] Furthermore, when the communications equipment authentication section 220 receives an excess alarm, which will be described later, from the terminal line switching control section 210, it issues a WAN line switching instruction to the WAN connection control section 520 of the WAN redundant communications equipment 500 to switch the connection destination of the WAN line.

[0056] The terminal line switching control unit 210 monitors the traffic volume between each ONU 300 connected to the PON termination unit 230. Specifically, the terminal line switching control unit 210 acquires the upstream and downstream traffic volumes of each ONU 300 connected to the PON termination unit 230, for example, for a predetermined period such as a unit time. The traffic volumes are acquired independently for each ONU 300. These traffic volumes are detected and acquired, for example, using a traffic counter (counter for the number of transmitted and received frames, the number of transmitted and received bytes, etc.) that is normally provided in the OLT 200.

[0057] The terminal line switching control unit 210 also sets a threshold value 260. The threshold value 260 is used to determine the degree of bandwidth congestion in the PON section between each ONU 300 connected to the PON termination unit 230. The threshold value 260 includes a first threshold value and a second threshold value. The first threshold value is used to determine whether the total traffic volume of the PON section between the OLT 200a and the ONU 300 exceeds the limit for a predetermined period of time. The second threshold value is used to determine whether the traffic volume (specific traffic volume) of the PON section between the OLT 200a and the ONU 300 (304) to which the WAN redundant communication device 500 is connected to the UNI termination unit 320 exceeds the limit for a predetermined period of time. Information on the ONU 300 (304) to which the WAN redundant communication device 500 is connected to the UNI termination unit 320 is obtained from the communication device authentication unit 220.

[0058] The threshold 260 may be set in advance or during processing. For example, the first threshold may be determined depending on the communication rate of the PON section between the OLT 200 and the ONU 300. For example, in the case of 1GE (Gigabit Ethernet)-PON, the communication rate of the PON section is 1.25 Gbps. For example, the first threshold may be determined by multiplying 80% of that (1.25 Gbps x 0.8 = 1 Gbps) by a predetermined period. The second threshold may be determined based on the relationship with the total number of ONUs 300 accommodated in the PON system 100a. Specifically, it is calculated by, for example, the first threshold / the total number of accommodated ONUs 300. This is a value obtained by equally allocating the first threshold to the ONUs 300 accommodated in the PON system 100a.

[0059] The terminal line switching control unit 210 performs excess determination to determine whether the total traffic volume and the specific traffic volume are exceeded using the first threshold and the second threshold, respectively. If the excess determination determines that the total traffic volume and the specific traffic volume are exceeded, an alarm (excess alarm) is output. The excess alarm is output to the communication device authentication unit 220.

[0060] [ONU] The PON termination unit 310 is a termination unit of the PON line, and receives control instructions from the OLT 200a and establishes communication with the OLT 200a. The PON termination unit 310 also acquires the link status of the UNI termination unit 320 and notifies the communication device authentication unit 220 of the OLT 200a. For example, the PON termination unit 310 monitors the link status of the UNI termination unit 320 at a predetermined time interval, and detects that a new device has been connected (link up) or that a connection with a connected device has been cut off (link down).

[0061] The UNI termination unit 320 is connected to the communication device 400 and / or the WAN redundant communication device 500 via the wired cable 700. It grasps the link status indicating that these devices are connected to the ONU 300 (link up) or that the connection between these devices and the ONU 300 has been released (link down).

[0062] [WAN redundant communication equipment] The wired WAN port unit 511 is connected to the UNI termination unit 320 of the ONU 303 via a wired cable 700. The mobile line WAN module unit 512 is connected to a mobile line such as LTE (Long Term Evolution).

[0063] The WAN connection control unit 520 controls the entire WAN redundant communication device 500. For example, it notifies the communication device authentication unit 220 of the OLT 200a that it is the WAN redundant communication device 500. Specifically, it generates a WAN redundant device notification message and transmits it to the OLT 200a. Furthermore, when it receives a WAN line switching instruction from the communication device authentication unit 220 of the OLT 200a, it switches the connection destination of the WAN line between the wired line and the mobile line. It also controls the activation / deactivation of the functions of the wired WAN port unit 511 and the mobile line WAN module unit 512.

[0064] The LAN connection port unit 530 establishes a link with the communication device 400 via a wired cable 800 to perform communication.

[0065] [ONU management table] Here, a description will be given of information items stored in the ONU management table 250. Fig. 4 is a diagram showing an example of the ONU management table 250 of this embodiment. As shown in this figure, in the ONU management table 250, ONU individual information 251, link status 252, and connected device information 253 are registered for each ONU 300 connected to the OLT 200a.

[0066] The ONU individual information 251 is information for uniquely identifying each ONU 300 connected to the OLT 200a. As described above, the communication device authentication unit 220 acquires and registers the information from the connected ONU 300 via the PON termination unit 230. Note that, in each ONU 300, ONU individual information for uniquely identifying the device itself is set in advance.

[0067] Link status 252 is information indicating whether communication device 400 or WAN redundant communication device 500 is connected to UNI termination unit 320 of ONU 310. If either device is connected, "link up" is registered, and if neither is connected, nothing is registered. Note that if neither is connected, "link down" may be registered. Link status 252 is acquired by communication device authentication unit 220 from connected ONU 300 via PON termination unit 230.

[0068] The connected device information 253 is information on devices connected to the UNI termination unit 320 of the ONU 300. In the example of this embodiment, for example, the communication devices 401-403 are registered in the records of the ONUs 301-303, respectively, and the WAN redundant communication device 500 is registered in the record of the ONU 304. Note that if the connected device is other than the WAN redundant communication device 500, nothing may be registered.

[0069] [Device identification process] Next, a description will be given of the flow of processing in which the OLT 200a identifies the device connected to the UNI termination unit 320 of the ONU 300. First, a description will be given of the flow of the device identification processing in the case where the connected device is the WAN redundant communication device 500.

[0070] 5 shows a process flow of device recognition processing in this embodiment when the WAN redundant communication device 500 is connected. This processing is started when the ONU 300 is connected to the OLT 200a.

[0071] In the PON system 100a, when the ONU 300 is connected to the OLT 200a, an ONU discovery process is executed to establish a link between the PON termination unit 230 of the OLT 200a and the PON termination unit 310 of the ONU 300 (step S1101).

[0072] When the ONU discovery process ends normally, the individual information of the connected ONU 300 is notified to the communication device authentication unit 220 via the PON termination unit 230 of the OLT 200a. That is, the PON termination unit 310 of the ONU 300 transmits the individual information of its own device (ONU individual information) to the PON termination unit 230 of the OLT 200a (step S1102).

[0073] The communication equipment authentication unit 220 of the OLT 200a acquires individual information of the ONU 300 that has completed the ONU discovery process from the PON termination unit 230, and registers the acquired information in the ONU individual information 251 of the ONU management table 250 (step S1103). Here, a new record is generated in the ONU management table 250 and registered.

[0074] Furthermore, when the ONU discovery process with the OLT 200a is completed, the ONU 300 enables the UNI termination unit 320 (step S1104). This enables a link to be established with the communication device 400 and / or the WAN redundant communication device 500 connected to the UNI termination unit 320.

[0075] When the link can be established, an ONU UNI discovery process is executed to establish a link between the UNI termination unit 320 and the destination device (here, the WAN redundant communication device 500) (step S1105).

[0076] The PON termination unit 310 of the ONU 300 monitors the link status of the UNI termination unit 320. When a link-up is detected (step S1106), a link-up notification is sent to the communication device authentication unit 220 of the OLT 200a (step S1107). The link-up is a notification that a link has been established with the communication device 400 or the WAN redundant communication device 500. The link-up notification is a notification that means that a link has been established.

[0077] The communication device authentication unit 220 of the OLT 200a that has received the notification links the ONU individual information 251 of the source ONU 300 in the ONU management table 250, and registers the fact that the UNI termination unit 320 has linked up in the link status 252 (step S1108). That is, "link up" is registered in the link status 252 of the record of the source ONU 300.

[0078] On the other hand, when a link is established with ONU300 by the above-mentioned ONU UNI discovery process, WAN connection control unit 520 of WAN redundant communication device 500 generates a WAN redundant communication device notification message (step S1109). The WAN redundant communication device notification message is a message notifying that it is WAN redundant communication device 500. Then, the WAN redundant communication device notification message is transmitted to communication device authentication unit 220 of OLT 200a via ONU300 connected to wired WAN port unit 511 (step S1110).

[0079] The communications equipment authentication unit 220 of the OLT 200a that has received the message registers the WAN redundant communications equipment 500 in the ONU management table 250 (step S1111). Here, the communications equipment authentication unit 220 links the WAN redundant communications equipment 500 to the ONU individual information 251 of the ONU 300 in the ONU management table 250, and registers information indicating that the WAN redundant communications equipment 500 is the WAN redundant communications equipment 500 in the connected equipment information 253. Then, the communications equipment authentication unit 220 transmits a notification indicating that the registration has been completed (registration completion notification) to the WAN connection control unit 520 of the WAN redundant communications equipment 500 (step S1112).

[0080] Next, the flow of the device recognition process when the device to be connected is the communications device 400 will be described.

[0081] 6 shows a process flow of the device recognition process when the communication device 400 is connected. This process is started when the ONU 300 is connected to the OLT 200a.

[0082] The link establishment process between the OLT 200a and the ONU 300 (steps S1101 to S1103), and the link establishment process between the ONU 300 and the communication equipment 400 (steps S1104 to S1108) are similar to those in the case of the WAN redundant communication equipment 500 described above.

[0083] When the connected device is the communication device 400, the communication device 400 does not transmit any message to the OLT 200a even when a connection with the ONU 300 is established.

[0084] Therefore, if no message is received for a predetermined period of time after step S1108, communications equipment authentication unit 220 of OLT 200a recognizes that the connected equipment is communications equipment 400. Then, in ONU management table 250, communications equipment authentication unit 220 links the ONU to ONU individual information 251 of ONU 300, and registers information indicating that the equipment is communications equipment 400 in connected equipment information 253. Note that step S1108 is a process of receiving a notification that UNI termination unit 320 has linked up, and registering the notification in ONU management table 250, as described above.

[0085] Here, the communications device authentication unit 220 determines whether a predetermined period of time has elapsed (step S1121). Then, if the predetermined period of time has elapsed without receiving any message, the communications device authentication unit 220 of the OLT 200a registers the communications device 400 in the ONU management table 250 (step S1122). Here, information indicating that it is the communications device 400 is registered in the connected device information 253 of the record in which "link up" was registered in the link status 252 in step S1108.

[0086] The "predetermined period" used by the communication device authentication unit 220 for the determination is set in advance.

[0087] If no information is received for a predetermined period of time, the communication device authentication unit 220 may not register any information in the connected device information 253 of the ONU management table 250. In this case, the OLT 200a interprets that the connected device is the communication device 400 (not the WAN redundant communication device 500) for a record in which link up is registered in the link status 252 and nothing is registered in the connected device information 253.

[0088] The OLT 200a executes this device recognition process every time one ONU 300 is connected. This allows the OLT 200a to recognize whether the device connected to the UNI termination unit 320 of the connected ONU 300 is the communication device 400 or the WAN redundant communication device 500.

[0089] [Traffic monitoring process] Next, a flow of a traffic monitoring process for monitoring traffic on a PON line will be described. The OLT 200a of this embodiment monitors traffic on a PON line in the PON system 100a. When the traffic volume on the PON line becomes congested (when a state occurs in which a specific ONU 300 has exclusive use of a band), the WAN redundant communication device 500 switches from wired communication of the OLT 200a to communication using a mobile line in order to stabilize communication.

[0090] 7 is a process flow of the traffic monitoring process. This process is started, for example, when a plurality of ONUs 300 are connected to the OLT 200a and at least one of them is an ONU 300 connected to a WAN redundant communication device 500 (hereinafter referred to as a replaceable ONU 300). Specifically, the process is started when a plurality of records are registered in the ONU management table 250 and at least one of the records has a link status 252 of "link up" and a connection device information 253 of "WAN redundant communication device".

[0091] It should be noted that, here, the first threshold value is assumed to be set in advance.

[0092] The terminal line switching control unit 210 of the OLT 200a identifies the ONUs 300 to be monitored for traffic (monitored ONUs) and calculates a second threshold (step S1201). Here, the terminal line switching control unit 210 acquires the ONU individual information 251 of a record in which the link status 252 is "link up" from the ONU management table 250. The ONUs 300 from which the ONU individual information 251 has been acquired are the ONUs to be monitored. Furthermore, the second threshold is calculated, for example, by the above method, using the number of ONUs 300 from which the ONU individual information 251 has been acquired.

[0093] The terminal line switching control unit 210 further identifies the ONU individual information 251 of the ONU (replaceable ONU) 300 whose connected device information 253 is the WAN redundant communication device 500 (step S1202). The replaceable ONU 300 is a determination target for determining whether or not to output an alarm notification. In this embodiment, it is the ONU 304. The replaceable ONU 300 is included in the ONUs to be monitored.

[0094] The terminal line switching control unit 210 starts monitoring the traffic with each ONU to be monitored (step S1203). Then, it performs an excess determination. Here, the terminal line switching control unit 210 detects the traffic volume with each ONU 300 to be monitored at a predetermined time interval, and calculates the total traffic volume by adding them up (step S1204). Then, it is determined whether the calculated total traffic volume exceeds the first threshold (total traffic volume>first threshold) (step S1205). If it does not exceed the first threshold, it returns to step S1204 and continues the process.

[0095] On the other hand, if the total traffic volume exceeds the first threshold, the terminal line switching control unit 210 judges whether the specific traffic volume exceeds the second threshold (specific traffic volume>second threshold) (step S1206). Note that the specific traffic volume is the traffic volume between the replaceable ONU300 (ONU304) identified in step S1202, as described above. If it does not exceed the first threshold, the process returns to step S1204 and continues.

[0096] On the other hand, if the specific traffic volume exceeds the second threshold, the terminal line switching control unit 210 determines that the traffic volume is exceeded, and notifies the communication equipment authentication unit 220 of an alarm indicating the exceedance (excess alarm) (step S1207).

[0097] Upon receiving the excess alarm, the communication device authentication unit 220 generates and transmits a WAN line switching instruction, which is an instruction to switch the WAN connection, to the WAN redundant communication device 500 connected to the replaceable ONU 300 (ONU 304) (step S1208). Here, the communication device authentication unit 220 transmits the WAN line switching instruction to the WAN connection control unit 520 of the WAN redundant communication device 500 via the ONU 304.

[0098] Upon receiving the WAN line switching instruction, the WAN connection control unit 520 first responds (replies) to the communication device authentication unit 220 of the OLT 200a that the WAN line switching instruction has been received (step S1209). After that, the mobile line WAN module unit 512 switches the WAN line connection from the wired WAN port unit 511 (step S1210). At this time, the WAN connection control unit 520 disables the function of the wired WAN port unit 511 and disconnects the link with the UNI termination unit 320 of the ONU 304 (step S1211).

[0099] When the PON termination unit 310 detects a link down (step S1212), it transmits a link down notification to the communication device authentication unit 220 of the OLT 200a (step S1213). The PON termination unit 310 monitors the link status of the UNI termination unit 320 of the ONU 304. The link down is when the link is cut off at the UNI termination unit 320.

[0100] The communication device authentication unit 220 that has received the link down notification updates the ONU management table 250 (step S1214). Here, the registration of the link status 252 in the record of the ONU 300 that sent the notification (here, ONU 304) is changed to "link down" and the data of the connected device information 253 is deleted. Note that the ONU individual information 251 may be maintained as it is, that is, the record itself may be left.

[0101] As described above, in the WAN redundant communications device 500, the mobile line WAN module unit 512 switches the connection of the WAN line from the wired WAN port unit 511. As a result, the replaceable ONU 300 (in this embodiment, the ONU 304) to which this WAN redundant communications device 500 is connected no longer uses the PON communication line, and is removed from the PON system 100a.

[0102] As described above, according to this embodiment, line congestion in the PON section is detected by controlling the OLT 200a. Then, when the PON communication line between the OLT 200a and the ONU 300 accommodated in the OLT 200a is congested, the replaceable ONU 300 is removed from the PON system 100a. This alleviates communication congestion in the PON system 100a. That is, since the WAN redundant communication device 500 whose traffic volume exceeds a threshold is separated from the PON system 100a, it becomes possible to ensure communication stability of other ONUs 300 to which the WAN redundant communication device 500 is not connected.

[0103] If the WAN redundant communication device 500 is connected to a replaceable ONU 300, communication can be continued through the mobile line, so that when the entire PON system 100a is taken into consideration, the communication bands of both the mobile line and the PON line can be used efficiently. In other words, the communication band can be used efficiently throughout the entire PON system 100a.

[0104] Furthermore, according to this embodiment, a two-stage judgment is performed between the total traffic volume and the specific traffic volume. That is, an excess judgment is also performed for the traffic volume between the OLT 200a and the replaceable ONU 300 (ONU 304), and if it is exceeded, the replaceable ONU 300 is removed from the PON system 100a. In general, a user of the WAN redundant communication device 500 connected to the ONU 300 removed from the PON system 100a must pay a communication fee for LTE or the like. In some cases, the fee is based on a pay-per-use system. However, by performing the control according to this embodiment, unnecessary switching control is prevented, and unnecessary burden in terms of fees on the user of the WAN redundant communication device 500 can be reduced.

[0105] Therefore, according to this embodiment, the communication of the entire PON system 100a can be stabilized, and the communication band can be used efficiently.

[0106] <<Third embodiment>> Next, a third embodiment to which the present invention is applied will be described.

[0107] The WAN redundant communication device 500 has a WAN redundant configuration to enhance the stability and robustness of communication. Here, it is assumed that after the traffic monitoring process of Fig. 7, there is a problem with the mobile line to which the WAN redundant communication device 500 is connected, and the connection via the mobile line is cut off.

[0108] When the mobile line is abnormally disconnected, the WAN connection control unit 520 of the WAN redundant communication device 500 activates the wired WAN port unit 511. Accordingly, the PON termination unit 310 of the replaceable ONU 300 (ONU 304) detects that the link status of the UNI termination unit 320 has been changed to link up, and notifies the OLT 200a.

[0109] However, when the PON line is congested, that is, when the total traffic volume exceeds the first threshold and the specific traffic volume exceeds the second threshold, it is possible that a WAN line switching instruction will be received again from the OLT 200a within a short period of time. The WAN line switching instruction is an instruction (notification) to switch the WAN connection destination of the WAN redundant communication device 500 to the mobile line, as described above.

[0110] If the mobile line has not been restored at this point, the WAN redundant communication device 500 cannot connect to the mobile line, and the WAN connection control unit 520 may get caught in a WAN line switching loop.

[0111] This embodiment is an embodiment that can also handle such a situation, that is, an embodiment that prevents the WAN redundant communication device 500 from falling into a switching loop.

[0112] The overall configuration of the PON system of this embodiment is basically the same as the PON system 100a of the second embodiment. However, in this embodiment, an OLT 200b is provided instead of the OLT 200a. Also, the function of the WAN connection control unit 520 of the WAN redundant communication device 500 is different. The following describes this embodiment, focusing on the differences from the second embodiment.

[0113] The WAN connection control unit 520 of this embodiment has, in addition to the functions of the second embodiment, a function of detecting that the link with the mobile line WAN module unit 512 has been abnormally disconnected, and a function of sending a notification (abnormal disconnection notification) to the communication device authentication unit 220 of the OLT 200b described later, indicating that the connection of the mobile line WAN module unit 512 has been abnormally disconnected.

[0114] Furthermore, the OLT 200b of this embodiment includes a timer 270 that counts time in addition to the components of the OLT 200a of the second embodiment. A functional block diagram of the OLT 200b of this embodiment is shown in Fig. 8. Components with the same names as the OLT 200a have at least the same functions as the components with the same names.

[0115] Furthermore, when the communication device authentication unit 220 receives an abnormal disconnection notification transmitted from the WAN redundant communication device 500, it masks the connected device information 253 of the record in the ONU management table 250 corresponding to the ONU 300 that is the source of the abnormal disconnection notification. The masking period (masking period) is determined in advance. After the masking period has elapsed, the communication device authentication unit 220 removes the mask from the connected device information 253.

[0116] The mask period is measured by the timer 270. That is, upon receiving an abnormal disconnection notification, the communications device authentication unit 220 causes the timer 270 to start measuring time.

[0117] [Abnormal disconnection process] FIG. 9 shows a process flow of an abnormal disconnection process when the mobile line WAN module unit 512 of the WAN redundant communications device 500 is abnormally disconnected.

[0118] The WAN connection control unit 520 of the WAN redundant communications device 500 detects that the link of the mobile line WAN module unit 512 has been abnormally disconnected (step S2101).

[0119] The WAN connection control unit 520 enables the function of the wired WAN port unit 511 (step S2102). As a result, the WAN redundant communication device 500 is connected to the ONU 300 via the wired WAN port unit 511. In other words, it is connected to the OLT 200b via the PON line.

[0120] When the function of the wired WAN port unit 511 of the WAN redundant communication device 500 is enabled, the UNI termination unit 320 of the ONU 300 connected by the wired cable 700 establishes a link with the WAN redundant communication device 500 (step S2103). Here, similar to the second embodiment, the PON termination unit 310 executes an ONU UNI discovery process to establish a link between the UNI termination unit 320 and the WAN redundant communication device 500.

[0121] The PON termination unit 310 monitors the link status of the UNI termination unit 320. When the ONU 300 detects that the link is up with the WAN redundant communication device 500 (step S2104), the PON termination unit 310 transmits a link-up notification to the communication device authentication unit 220 of the OLT 200b (step S2105).

[0122] The communication equipment authentication unit 220 of the OLT 200b that has received the link-up notification registers the link-up notification in the ONU management table 250 (step S2106). Here, the fact that the UNI termination unit 320 of the ONU 300 has linked up is registered in association with individual information of the source ONU 300 (here, ONU 304).

[0123] At this time, the ONU 300 transmits the link-up notification including its own individual information. If there is a record in the ONU management table 250 that has the individual information as ONU individual information 251, the communication device authentication unit 220 registers the individual information in the link status 252 of the record. On the other hand, if there is no such record, a new record is added and registered.

[0124] When the WAN redundant communication device 500 links up with the ONU 300, the WAN connection control unit 520 of the WAN redundant communication device 500 generates a WAN redundant device notification message (step S2107). The link up is performed between the wired WAN port unit 511 of the WAN redundant communication device 500 and the UNI termination unit 320 of the ONU 300 connected by the wired cable 700. The WAN redundant device notification message is a message for notifying the communication device authentication unit 220 of the OLT 200b that it is the WAN redundant communication device 500. At this time, the WAN redundant device notification message includes a notification (abnormal disconnection notification) that means that the mobile line WAN module unit 512 has been abnormally disconnected. Then, the WAN connection control unit 520 transmits the message to the communication device authentication unit 220 of the OLT 200b via the ONU 300 connected to the wired WAN port unit 511 (step S2108).

[0125] The communication device authentication unit 220 of the OLT 200b that receives the WAN redundant device notification message including the abnormal disconnection notification registers the WAN redundant device notification message in the ONU management table 250 (step S2109). Here, the communication device authentication unit 220 registers information indicating that the WAN redundant communication device is the WAN redundant communication device 500 in the connection device information 253 in association with the ONU individual information 251 of the ONU 300.

[0126] The communications equipment authentication unit 220 of the OLT 200b determines whether or not a notification that the mobile line has been abnormally disconnected has been received from the WAN redundant communications equipment 500 (step S2110). That is, it determines whether or not the WAN redundant equipment notification message includes an abnormal disconnection notification.

[0127] When an abnormal disconnection notification is received from the WAN redundant communication device 500, the communication device authentication unit 220 masks the connected device information 253 of the corresponding ONU 300 in the ONU management table 250 (step S2111). Here, the fact that the communication device connected to the UNI termination unit 320 of the corresponding ONU 300 is the WAN redundant communication device 500 is masked.

[0128] Then, communications device authentication unit 220 starts counting the masking period using timer 270 (step S2112). The masking period is set in advance.

[0129] When the masking period has elapsed (step S2113), the communications equipment authentication unit 220 removes the masking from the ONU management table 250 (step S2114). After removing the masking, the communications equipment authentication unit 220 transmits a registration completion notification to the WAN connection control unit 520 of the WAN redundant communications equipment 500 (step S2115).

[0130] In step S2110, if an abnormal disconnection notification has not been received from the WAN redundant communication device 500, the process proceeds to step S2115. Then, the communication device authentication unit 220 of the OLT 200b transmits a registration completion notification to the WAN connection control unit 520 of the WAN redundant communication device 500.

[0131] During this process, the OLT 200b continues to monitor the traffic volume. Even if the communication device authentication unit 220 receives an excess alarm notification from the terminal line switching control unit 210, if the connected device information 253 is masked, the communication device authentication unit 220 does not transmit a WAN line switching instruction to the WAN redundant communication device 500. The excess alarm notification is transmitted from the terminal line switching control unit 210 when the total traffic volume exceeds the first threshold.

[0132] As described above, according to this embodiment, the same effects as those of the above-mentioned embodiments can be obtained. Furthermore, according to this embodiment, when the mobile line WAN module unit 512 of the WAN redundant communication device 500 is abnormally disconnected, the WAN connection control unit 520 can be prevented from falling into a WAN line switching loop under the control of the OLT 200b.

[0133] <Variation 1> In each of the above embodiments, in the PON system 100 (100a, hereinafter represented by 100, the same applies to the others), when the total traffic volume exceeds the first threshold and the specific traffic volume exceeds the second threshold, the ONU 300 to which the WAN redundant communication device 500 is connected is disconnected from the PON system 100. However, the present invention is not limited to this method.

[0134] For example, when the total traffic volume exceeds a first threshold, the ONU 300 to which the WAN redundant communication device 500 is connected may be disconnected from the PON system 100 regardless of the specific traffic volume.

[0135] According to this modification, the number of determinations is smaller than in the above embodiment, and the desired effect can be achieved with simpler processing.

[0136] <Variation 2> In addition, in each of the above embodiments and modifications, the case where the WAN redundant communication device 500 is connected to one ONU 300 (hereinafter, replaceable ONU 300) has been described as an example. However, a plurality of replaceable ONUs 300 may be connected to the OLT 200 (200a, 200b).

[0137] In this case, for example, in step S1206, all replaceable ONUs 300 whose specific traffic volume exceeds the second threshold value may be disconnected from the PON system 100.

[0138] Also, in step S1206, among the replaceable ONUs 300 whose specific traffic volume exceeds the second threshold, only the replaceable ONU 300 with the largest traffic volume may be disconnected from the PON system 100. In this case, each time one replaceable ONU 300 is disconnected (for example, after it is determined as Yes in step S1206 of the traffic monitoring process), the second threshold is recalculated and updated. That is, the second threshold is calculated using the latest number of ONUs 300 (including replaceable ONUs 300) in the PON system 100. Subsequent processes are performed using the updated second threshold.

[0139] Furthermore, without using the second threshold, when the total traffic volume exceeds the first threshold in step S1205, the replaceable ONU 300 with the largest traffic volume among the replaceable ONUs 300 may be disconnected from the PON system 100.

[0140] Furthermore, in the above traffic monitoring process, after it is determined as Yes in step S1205, the terminal line switching control unit 210 may refer to the ONU management table 250 and determine whether or not there is a replaceable ONU 300 that can be disconnected. If there is not, the process after S1206 is not performed.

[0141] <Variation 3> In the above embodiments and modifications, the first threshold, the second threshold, and the third threshold are described as being preset, but are not limited to this. For example, at the beginning of the traffic monitoring process, the terminal line switching control unit 210 may be configured to calculate them according to the number of connected ONUs 300.

[0142] <Variation 4> In addition, in each of the above embodiments and modifications, the traffic monitoring process is started when a plurality of ONUs 300 are registered and at least one of them becomes a replaceable ONU 300, but this is not limited to the above. For example, the traffic monitoring process may be started in response to a user instruction and ended according to a user instruction.

[0143] <Variation 5> In the above embodiments and modifications, the OLT 200 collects the status of the ONU 300 by receiving a WAN redundant device notification message or by waiting for a predetermined period of time after receiving a link-up notification. However, the method of collecting the status of the ONU 300 is not limited to this. For example, the OLT 200 may make an inquiry to the ONU 300 from which it has received the ONU individual information at a predetermined time interval and collect the link status.

[0144] Also, the traffic volume may be detected on the ONU 300 side, and the OLT 200 may collect the traffic volume from each ONU 300 at a predetermined time interval.

[0145] [Hardware configuration] The above-mentioned OLT 200, ONU 300, and WAN redundant communication equipment 500 may be realized by, for example, a general-purpose information processing device.

[0146] A general-purpose information processing device includes, for example, a CPU (Central Processing Unit) 191, a main memory device (memory) 192, an auxiliary memory device 193, a communication I / F 194, and an expansion I / F 195, which are interconnected by an internal bus, as shown in FIG. 10.

[0147] The CPU 191 realizes the above-mentioned functions and centrally controls the entire device by, for example, loading a program stored in the auxiliary storage device 193 into the main storage device 192 and executing the program. Note that, instead of the CPU 191, one or more processors such as an MPU (Micro Processing Unit) may be used.

[0148] The main storage device 192 is a memory such as a RAM (Random Access Memory), etc. The main storage device 192 is a work area when the CPU 191 processes programs and the like executed by the device.

[0149] The auxiliary storage device 193 is, for example, a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), etc. The auxiliary storage device 193 stores various programs executed by the device. The auxiliary storage device 193 may include a storage medium such as a flexible disk, a hard disk, an optical disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, a DVD, etc.

[0150] The programs stored in the auxiliary storage device 193 can be provided as program products recorded on a non-transitory computer-readable storage medium. The auxiliary storage device 193 can be used to store various programs recorded on the non-transitory computer-readable storage medium for a medium to long term.

[0151] The communication I / F 194 is an interface for inputting and outputting signals and data by wire or wirelessly. In this embodiment, an optical fiber 600, a wired cable 700, a mobile line, etc. are connected. Each device transmits and receives information (data) required for processing between other devices via the communication I / F 194.

[0152] The expansion I / F 195 is an interface for connecting a display device, an input device, etc. The display device is, for example, a liquid crystal monitor, etc. The input device is, for example, a device that accepts user operations such as a keyboard or a mouse.

[0153] The above-mentioned functions of each device are realized by the CPU 191 loading a program stored in the auxiliary storage device 193 into the main storage device 192 and executing it.

[0154] The ONU management table 250 is constructed, for example, in the auxiliary storage device 193. The threshold value 260 is also stored in the auxiliary storage device 193.

[0155] The hardware configuration of each device is not limited to the above. Each function (server) of each device may be implemented, for example, by an integrated circuit (IC) dedicated to each process, an application specific integrated circuit (ASIC), a system on chip (SOC), a field programmable gate array (FPGA), or the like.

[0156] In addition, the programs for implementing the above-mentioned functions of each device can be recorded on a computer-readable storage medium. The storage medium can be a non-transient medium such as a semiconductor memory, a hard disk, a magnetic recording medium, or an optical recording medium. The present invention can also be embodied as a computer program product.

[0157] In the process flow used in the above description, multiple steps (processes) are described in order, but the order of execution of each step is not limited to the order described. For example, the order of the steps shown in the figure can be changed to a range that does not affect the content, such as executing each process in parallel.

[0158] Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications that can be understood by those skilled in the art can be made. Each embodiment and modification can be appropriately combined with other embodiments. For example, the network configuration and the configuration of each element shown in each drawing are examples to help understand the present invention, and the present invention is not limited to the configurations shown in these drawings.

[0159] Finally, preferred embodiments of the present invention will be summarized as follows: A part or all of the above-described embodiments can be described as follows, but are not limited to the following. (Appendix 1) An OLT (Optical Line Terminal) of a PON (Passive Optical Network) system, a terminal line switching control unit that detects traffic volume between each of a plurality of optical subscriber devices (ONUs) accommodated in the network and outputs an alarm notification when a total traffic volume between the ONUs and each of the optical subscriber devices is greater than a first threshold value; a communication device authentication unit that outputs, when the alarm notification is output, a switching instruction, which is an instruction to switch a connection destination from the predetermined line to a mobile line, to a first communication device connected to a replaceable ONU via a predetermined line via a replaceable ONU that is at least one ONU of the plurality of ONUs; The plurality of ONUs are each connected to one end of an optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line to which the OLT is connected, and the other end of the optical fiber line branched by the optical coupler is connected, The replaceable ONU is the ONU to which a communication device is connected, the first communication device being the ONU; The first communication device is an OLT of a PON system that is a communication device connectable to the specified line and the mobile line. (Appendix 2) In the OLT of the PON system described in Appendix 1, It is desirable that, when the total traffic volume is greater than the first threshold value, the terminal line switching control unit further detects a specific traffic volume, which is the traffic volume between the replaceable ONU, and outputs the alarm notification only when the specific traffic volume is greater than a predetermined second threshold value. (Appendix 3) In the OLT of the PON system described in Appendix 1 or 2, Further, an ONU management table for managing the ONUs accommodated therein is provided, The communication device authentication unit When the first communication device is connected to the replaceable ONU, receiving a message from the first communication device via the replaceable ONU; When the message is received, the connected device information is registered in the ONU management table in association with the information identifying the replaceable ONU; It is preferable that the connected device information is information indicating that the device connected to the replaceable ONU is the first communication device. (Appendix 4) In the OLT of the PON system described in Appendix 3, The communication device authentication unit When receiving an abnormal disconnection notification from the first communication device via the replaceable ONU, register information indicating that the device connected to the replaceable ONU is the first communication device in the connected device information of the ONU management table in association with the replaceable ONU; Masking the connected device information in the ONU management table for a predetermined masking period; the abnormal disconnection notification is a notification transmitted from the first communication device after switching a connection to the mobile line, the notification indicating that the mobile line has been abnormally disconnected; When the connected device information is masked in the ONU management table, it is preferable that the communication device authentication unit does not output the switching instruction to the first communication device even if the alarm notification is output. (Appendix 5) a WAN (Wide Area Network) port section for connecting to an ONU (Optical Network Unit) via a predetermined line; A mobile line WAN module part for connecting to a mobile line; a connection control unit that switches a connection destination between the predetermined line and the mobile line, The connection control unit is When the ONU is connected, a message is sent via the ONU to the OLT (Optical Line Terminal), which is the central office side device of the PON system that accommodates the ONU. A redundant communication device that switches a connection from the specified line to the mobile line when a switching instruction is received from the OLT via the ONU to which it is connected, the switching instruction being an instruction to switch a connection destination from the specified line to the mobile line. (Appendix 6) In the redundant communication device according to appendix 5, The connection control unit is If the connection to the mobile line is disconnected due to an abnormality in the mobile line, it is desirable to switch the connection to the specified line, connect to the ONU, and send a notification to the OLT via the ONU indicating that the mobile line has been abnormally disconnected. (Appendix 7) An OLT (Optical Line Terminal) is a central office device connected to one end of the optical fiber line. and a plurality of ONUs (Optical Network Units) which are optical subscriber devices each connected to the other end of the optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line, At least one of the plurality of ONUs, which is a replaceable ONU, is a communication device connected to the replaceable ONU via a predetermined line, which is a first communication device connectable to the predetermined line and a mobile line; The OLT is a terminal line switching control unit that detects a traffic volume between each of the plurality of ONUs, and outputs an alarm notification when a total traffic volume between the plurality of ONUs is greater than a first threshold value; A PON (Passive Optical Network) system comprising: a communication equipment authentication unit that, when the alarm notification is output, outputs an instruction to the first communication equipment via the replaceable ONU to switch the connection destination from the specified line to the mobile line. (Appendix 8) A bandwidth control method by an OLT (Optical Line Terminal) of a PON (Passive Optical Network) system, A traffic detection step of detecting the amount of traffic between the OLT and each of a plurality of ONUs (Optical Network Units) that are optical subscriber devices accommodated in the OLT; a determining step of outputting an alarm notification when a total traffic volume, which is the sum of the detected traffic volumes, is greater than a predetermined first threshold value; a switching instruction step of outputting, when the alarm notification is output, a switching instruction which is an instruction to switch a connection destination from a predetermined line to a mobile line to a first communication device connected to at least one of the plurality of ONUs via a replaceable ONU which is an ONU of the plurality of ONUs; The plurality of ONUs are each connected to one end of an optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line to which the ONU is connected, and the other end of the optical fiber line branched by the optical coupler is connected, The replaceable ONU is the ONU to which a communication device connected is the first communication device, A bandwidth control method, wherein the first communication device is a communication device that can be connected to the specified line and the mobile line. (Appendix 9) The computer of the OLT (Optical Line Terminal) of the PON (Passive Optical Network) system a traffic detection step for detecting the amount of traffic between each of a plurality of ONUs (Optical Network Units) that are optical subscriber devices accommodated in the OLT, the ONUs being connected to the other ends of optical fiber lines branched by an optical coupler inserted in the middle of the optical fiber line to which the OLT is connected at one end; a determination step of outputting an alarm notification when a total traffic volume, which is the sum of the detected traffic volumes, is greater than a first threshold value; a program for executing, when the alarm notification is output, a switching instruction procedure for outputting, via at least one ONU of the plurality of ONUs, a switching instruction to a replaceable ONU which is a first communication device capable of connecting to a specified line and a mobile line, to the first communication device, the switching instruction being an instruction to switch the connection destination from the specified line to the mobile line, when the alarm notification is output, to the first communication device. (Appendix 10) A redundant communication device connected to an ONU (Optical Network Unit) of a PON (Passive Optical Network) system via a predetermined line, a WAN (Wide Area Network) port unit that connects to the ONU via the predetermined line; A computer of a redundant communication device including a mobile line WAN module unit for connecting to a mobile line, a transmission procedure for transmitting a message via the ONU to an OLT (Optical Line Terminal) that accommodates the ONU when the ONU is connected to the ONU; A program for executing a switching procedure for switching the connection destination from the specified line to the mobile line when a switching instruction is received from the OLT via the ONU to which it is connected, the switching instruction being an instruction to switch the connection destination from the specified line to the mobile line. The form of Supplementary Note 7 can be developed into the form of Supplementary Note 2-4 and / or Supplementary Note 6, similarly to Supplementary Note 1 and / or Supplementary Note 5. The forms of Supplementary Note 8 and Supplementary Note 9 can be developed into the form of Supplementary Note 2-4, similarly to Supplementary Note 1. The form of Supplementary Note 10 can be developed into the form of Supplementary Note 6, similarly to Supplementary Note 5.

[0160] The disclosure of Patent Document 1 is incorporated herein by reference. Within the framework of the entire disclosure of the present invention (including the scope of claims), and further based on the basic technical idea, the embodiments or variants can be modified or adjusted. Furthermore, within the framework of the disclosure of the present invention, various combinations or selections of the various disclosed elements (including each element of each claim, each element of each embodiment or variant, each element of each drawing, etc.) are possible. In other words, the present invention naturally includes various modifications and corrections that a person skilled in the art would be able to make according to the entire disclosure including the scope of claims and the technical idea. In particular, with regard to the numerical ranges described in this specification, any numerical value or subrange included in the range should be construed as being specifically described even if not otherwise specified. [Explanation of symbols]

[0161] 100: PON system, 100a: PON system, 191: CPU, 192: main memory device, 193: auxiliary memory device, 194: communication I / F, 195: expansion I / F, 200: OLT, 200a: OLT, 200b: OLT, 210: terminal line switching control unit, 220: communication device authentication unit, 230: PON termination unit, 250: ONU management table, 251: ONU individual information, 252: link status, 253: connection device information, 260: threshold, 270: timer, 300:ONU, 301:ONU, 302:ONU, 303:ONU, 304:ONU, 310:PON termination, 320:UNI termination, 400: communication device, 401: communication device, 402: communication device, 403: communication device, 404: communication device, 500: WAN redundant communication device, 510: WAN port, 511: wired WAN port section, 512: mobile line WAN module section, 520: WAN connection control section, 530: LAN connection port section, 600: optical fiber, 601: optical fiber, 602: optical fiber, 603: optical fiber, 604: optical fiber, 690: optical coupler, 700: Wired cable, 701: Wired cable, 702: Wired cable, 703: Wired cable, 704: Wired cable, 800: Wired cable, 900: PON system, 920: OLT, 930: ONU, 940: Communication equipment, 960: Optical fiber cable, 969: Optical coupler, 970: Wired cable

Claims

1. An OLT (Optical Line Terminal) of a PON (Passive Optical Network) system, a terminal line switching control unit that detects traffic volume between each of a plurality of optical network units (ONUs) accommodated in the network and outputs an alarm notification when a total traffic volume, which is a sum of the traffic volumes, is greater than a first threshold value; a communication device authentication unit that outputs, when the alarm notification is output, a switching instruction, which is an instruction to switch a connection destination from the predetermined line to a mobile line, to a first communication device connected to a replaceable ONU that is at least one ONU of the plurality of ONUs via the replaceable ONU; The plurality of ONUs are each connected to one end of an optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line to which the OLT is connected, and the other end of the optical fiber line branched by the optical coupler is connected, The replaceable ONU is the ONU to which a communication device connected is the first communication device, The first communication device is an OLT of a PON system, which is a communication device connectable to the specified line and the mobile line.

2. 2. The OLT of the PON system according to claim 1, The terminal line switching control unit, when the total traffic volume is greater than the first threshold value, further detects a specific traffic volume, which is the traffic volume between the replaceable ONU, and outputs the alarm notification only when the specific traffic volume is greater than a predetermined second threshold value.

3. 3. An OLT of a PON system according to claim 1, An ONU management table for managing the ONUs accommodated therein is further provided, The communication device authentication unit receiving a message from the first communication device via the replaceable ONU when the first communication device is connected to the replaceable ONU; When the message is received, the connected device information is registered in the ONU management table in association with the information for identifying the replaceable ONU; The connected device information is information indicating that the device connected to the replaceable ONU is the first communication device.

4. An OLT for a PON system according to claim 3, The communication device authentication unit When receiving an abnormal disconnection notification from the first communication device via the replaceable ONU, register information indicating that the device connected to the replaceable ONU is the first communication device in the connected device information of the ONU management table in association with the replaceable ONU; Masking the connected device information in the ONU management table for a predetermined masking period; the abnormal disconnection notification is a notification transmitted from the first communication device after switching a connection to the mobile line, the notification indicating that the mobile line has been abnormally disconnected; When the connected device information is masked in the ONU management table, the communication device authentication unit does not output the switching instruction to the first communication device even if the alarm notification is output.

5. a WAN (Wide Area Network) port section for connecting to an ONU (Optical Network Unit) via a predetermined line; a mobile line WAN module unit for connecting to a mobile line; a connection control unit that switches a connection destination between the predetermined line and the mobile line, The connection control unit is When a connection is made to the ONU, a message is sent via the ONU to an OLT (Optical Line Terminal) which is a central office side device of the PON system that accommodates the ONU. A redundant communication device that switches a connection from the specified line to the mobile line when a switching instruction is received from the OLT via the ONU to which it is connected, the switching instruction being an instruction to switch a connection destination from the specified line to the mobile line.

6. 6. The redundant communication device according to claim 5, The connection control unit is A redundant communication device that, when the connection to the mobile line is disconnected due to an abnormality in the mobile line, switches the connection to the specified line, connects to the ONU, and sends a notification to the OLT via the ONU indicating that the mobile line has been abnormally disconnected.

7. An OLT (Optical Line Terminal) which is a central office device connected to one end of an optical fiber line; and a plurality of ONUs (Optical Network Units) which are optical subscriber devices each connected to the other end of the optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line, At least one of the plurality of ONUs, i.e., a replaceable ONU, is a communication device connected to the replaceable ONU via a predetermined line, the communication device being a first communication device connectable to the predetermined line and a mobile line; The OLT includes: a terminal line switching control unit that detects a traffic volume between each of the plurality of ONUs, and outputs an alarm notification when a total traffic volume between the plurality of ONUs is greater than a first threshold value; a communication device authentication unit that outputs, when the alarm notification is output, an instruction to the first communication device via the replaceable ONU to switch a connection destination from the specified line to the mobile line.

8. A bandwidth control method by an OLT (Optical Line Terminal) of a PON (Passive Optical Network) system, comprising: a traffic detection step of detecting the amount of traffic between the OLT and each of a plurality of ONUs (Optical Network Units) that are optical subscriber devices accommodated in the OLT; a determining step of outputting an alarm notification when a total traffic volume, which is the sum of the detected traffic volumes, is greater than a predetermined first threshold value; a switching instruction step of outputting, when the alarm notification is output, a switching instruction which is an instruction to switch a connection destination from a predetermined line to a mobile line to a first communication device connected to at least one ONU of the plurality of ONUs via a replaceable ONU which is an ONU of the plurality of ONUs; The plurality of ONUs are each connected to one end of an optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line to which the OLT is connected, and the other end of the optical fiber line branched by the optical coupler is connected, The replaceable ONU is the ONU to which a communication device connected is the first communication device, A bandwidth control method, wherein the first communication device is a communication device that can be connected to the specified line and the mobile line.

9. The OLT (Optical Line Terminal) computer of the PON (Passive Optical Network) system a traffic detection procedure for detecting the amount of traffic between each of the ONUs (Optical Network Units) connected to one end of an optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line connected to the OLT; the ONUs being a plurality of optical subscriber devices accommodated in the OLT, and the OLT and each of the ONUs being connected to the other end of the optical fiber line branched by an optical coupler inserted in the middle of the optical fiber line; a determination step of outputting an alarm notification when a total traffic volume, which is the sum of the detected traffic volumes, is greater than a first threshold value; A program for executing, when the alarm notification is output, a switching instruction procedure for outputting, via an ONU to a replaceable ONU, which is at least one ONU of the multiple ONUs and has a connected communication device that is a first communication device that can be connected to a specified line and a mobile line, a switching instruction that is an instruction to the first communication device to switch the connection destination from the specified line to the mobile line.

10. A redundant communication device connected to an ONU (Optical Network Unit) of a PON (Passive Optical Network) system via a predetermined line, a WAN (Wide Area Network) port unit that connects to the ONU via the predetermined line; A computer of a redundant communication device including a mobile line WAN module unit for connecting to a mobile line, a transmission procedure for transmitting a message via the ONU to an OLT (Optical Line Terminal) that accommodates the ONU when the ONU is connected; A program for executing a switching procedure for switching a connection destination from the specified line to the mobile line when a switching instruction is received from the OLT via the connected ONU, which is an instruction to switch a connection destination from the specified line to the mobile line.

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