Communication system

Abstract

This communication system comprises: an interface that stores communication of user devices registered in first user information; a transfer unit that transfers a signal to and from a host device on the basis of second user information which includes the first user information; and a synchronization unit that, if the number of registrations of user devices registered in the first user information is smaller than the number of registrations of user devices registered in the second user information in the transfer unit, which is in cold standby, registers startup registration user information, which is information synchronized with the first user information, in the transfer unit at the time of startup from cold standby. After startup from cold standby, the synchronization unit may register, in the transfer unit, post-startup registration user information, which is information other than the startup registration user information, in the second user information.

Description

communication systems

[0001] The present invention relates to communication systems.

[0002] Patent Document 1 discloses an OLT (Optical Line Terminal) that reduces power consumption by putting some of a plurality of redundant line concentrator switches into cold standby mode depending on traffic conditions and the like.

[0003] Patent No. 5323729

[0004] When the concentrator switch provided in the OLT is started, the kernel is started, the forwarding unit (Layer 2 forwarding unit) that forwards signals is initialized, the operating system is started, and then the application is started.Furthermore, user information (forwarding table) that indicates the forwarding destination of the main signal is registered in the forwarding unit, and the start-up of the concentrator switch is completed.

[0005] Here, the more user information (information about user devices) is registered in the concentrator switch, the longer the startup time from cold standby becomes. When starting up from cold standby, the problem arises that the startup time from cold standby of the concentrator switch cannot be shortened because the amount of user information registered in the concentrator switch is large.

[0006] In view of the above circumstances, an object of the present invention is to provide a communication system that can shorten the startup time of a line concentrator switch from cold standby.

[0007] One aspect of the present invention is a communication system comprising: an interface that accommodates communications of each user device registered in first user information; a transfer unit that transfers signals between a higher-level device and the interface based on second user information including the first user information; and a synchronization unit that, when the number of registered user devices registered in the first user information is less than the number of registered user devices registered in the second user information in the transfer unit that is in cold standby, registers startup-time registered user information, which is information synchronized with the first user information, in the transfer unit upon startup from the cold standby.

[0008] According to the present invention, it is possible to reduce the startup time of a line concentrator switch from cold standby.

[0009] 1 is a diagram showing an example of the configuration of a communication system in a first embodiment. FIG. 2 is a diagram showing an example of the configuration of a PON interface and a line concentrator switch in the first embodiment. FIG. 3 is a diagram showing an example of PON user information in the first embodiment. FIG. 4 is a diagram showing examples of startup-registered user information and post-startup registered user information in the first embodiment. FIG. 5 is a flowchart showing an example of the operation of a communication system in the first embodiment. FIG. 6 is a diagram showing an example of the configuration of a communication system in a second embodiment. FIG. 7 is a diagram showing an example of the configuration of a PON interface, a line concentrator switch, and an OLT control unit in the second embodiment. FIG. 8 is a flowchart showing an example of the operation of a communication system in the second embodiment. FIG. 9 is a diagram showing an example of the configuration of a communication system in a third embodiment. FIG. 10 is a diagram showing an example of the configuration of a PON interface, a line concentrator switch, and an OLT control unit in the third embodiment. FIG. 11 is a flowchart showing an example of the operation of a communication system in the third embodiment. FIG. 12 is a diagram showing an example of the configuration of a communication system in a fourth embodiment. FIG. 13 is a diagram showing an example of the configuration of a collection device in the fourth embodiment. FIG. 14 is a flowchart showing an example of the operation of a communication system in the fourth embodiment.

[0010] Embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) Fig. 1 is a diagram showing an example of the configuration of a communication system 1a in a first embodiment. The communication system 1a performs communication using optical signals. The communication system 1a includes an OLT 10a, an OLT operation unit 20, an upper network operation unit 30, K ("K" is an integer equal to or greater than 2) optical splitters 40, a plurality of conversion devices 50a, and L ("L" is an integer equal to or greater than 2) upper networks 60. The upper network 60 includes one or more upper devices 61.

[0011] The OLT 10a includes K PON interfaces 11, M (where "M" is an integer equal to or greater than 2) line concentrator switches 12a, and an OLT control unit 13a. An optical splitter 40 is connected to the PON interfaces 11 via optical fibers. In addition, a plurality of conversion devices 50a (user devices) are connected to the PON interfaces 11 via optical fibers and the optical splitter 40.

[0012] The concentrator switch 12a is connected to each PON interface 11. The concentrator switch 12a is also connected to each higher-level device 61. This provides redundancy to the transmission path of the main signal, thereby improving the availability of the communication system 1a.

[0013] Link aggregation (LAG: Link Aggregation Group) may be applied to the transmission path of the main signal between the multiple line concentrators 12a and the upper network 60. In the section from the conversion device 50a to the OLT 10a, the conversion device 50a may be identified by using, for example, identification information (VLAN ID) of a Virtual Local Area Network (VLAN).

[0014] Each device (or part of it) of the present invention can also be realized by a computer and a program, and the program can be recorded on a recording medium or provided via a network.

[0015] Some functions of the OLT 10a are realized as software by a processor such as a CPU (Central Processing Unit) executing a program stored in a storage unit having a non-volatile storage medium (non-transitory storage medium). The program may be recorded on a computer-readable storage medium or may be recorded in the storage unit via a network. Examples of computer-readable storage media include portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), and CD-ROMs (Compact Disc Read Only Memory), and non-transitory storage devices such as hard disks or solid-state drives (SSDs) built into computer systems.

[0016] Some functions of OLT 10a may be realized using hardware (accelerator) including an electronic circuit (electronic circuit or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0017] The OLT 10a is an optical line termination device. The OLT 10a is installed in a central office of a telecommunications carrier. The OLT 10a accommodates communications from one or more converters 50a via optical fibers and an optical splitter 40.

[0018] The OLT operation unit 20 is an element management system (EMS) for the OLT. The OLT operation unit 20 manages the operation of the OLT 10a. Here, the OLT operation unit 20 transfers control signals transmitted from the OLT 10a to the upper network operation unit 30. The OLT operation unit 20 also transfers control signals transmitted from the upper network operation unit 30 to the OLT 10a.

[0019] The upper network operation unit 30 is an equipment management system (EMS) for the upper network. The upper network operation unit 30 manages the operation of a plurality of upper networks 60. Here, the upper network operation unit 30 transfers a control signal transmitted from the OLT operation unit 20 to an upper device 61 of the upper network 60. The upper network operation unit 30 also transfers a control signal transmitted from the upper device 61 to the OLT operation unit 20.

[0020] The optical splitter 40 uses optical fibers to connect the OLT 10a and each ONU 50. The optical splitter 40 splits the optical signal transmitted from the OLT 10a and transmits it to each ONU 50a. The optical splitter 40 combines the optical signals transmitted from each ONU 50a and transmits it to the OLT 10a.

[0021] The conversion device 50a is an optical network unit (ONU). The conversion device 50a is installed, for example, in a user's home. The conversion device 50a converts an optical signal input from the optical splitter 40 into an electrical signal. The conversion device 50a converts the input electrical signal into an optical signal. One or more user terminals (not shown) are connected to the conversion device 50a. The conversion device 50a transmits a main signal transmitted from the user terminal (not shown) to the OLT 10a via the optical splitter 40.

[0022] The upper network 60 provides a predetermined communication service to the conversion device 50a that communicates with the OLT 10a. The upper network 60 has a plurality of ports. Each port of the upper network 61 is connected to a predetermined port of the line concentrator 12a.

[0023] Next, the OLT 10a will be described in detail. Fig. 2 is a diagram showing an example of the configuration of the PON interface 11 and the line concentrator 12a in the first embodiment. The PON interface 11 includes a PON storage unit 111, a PON control unit 112, and a PON forwarding unit 113. The line concentrator 12a includes a switch storage unit 121, a switch control unit 122, and a switch forwarding unit 123. The switch control unit 122 includes a synchronization unit 124 and a registration unit 125.

[0024] The PON interface 11 is an interface device for a passive optical network (PON). For example, when authenticating the conversion device 50a, the PON interface 11 acquires the MAC address of the conversion device 50a based on the Multi-Point Control Protocol (MPCP). For example, the PON interface 11 transfers the main signal transmitted from the conversion device 50a to the switch transfer unit 123. For example, the PON interface 11 transfers the main signal transmitted from the switch transfer unit 123 to the conversion device 50a.

[0025] The PON storage unit 111 stores PON user information 100 (first user information). The PON user information includes identification information "user ID" of a PON user device. The identification information of the user device is identification information of the conversion device 50a. The PON user information may register the guaranteed bandwidth and maximum bandwidth of the conversion device 50a in association with the identification information "user ID" of the user device.

[0026] 3 is a diagram showing an example of PON user information 100 in the first embodiment. In the PON user information 100, a "user ID" is identification information of a user device of the conversion device 50a that communicates with the PON interface 11, and the "guaranteed bandwidth" and "maximum bandwidth" are associated with each other.

[0027] 2, the description of the OLT 10a will be continued. The PON control unit 112 controls the operation of the PON interface 11. The PON control unit 112 transmits the PON user information 100 to the synchronization unit 124.

[0028] The PON transfer unit 113 transfers an electrical signal based on the optical signal transmitted from the conversion device 50a to the switch transfer unit 123. The PON transfer unit 113 transfers an optical signal based on the electrical signal transmitted from the switch transfer unit 123 to the conversion device 50a.

[0029] The line concentrator 12a is a Layer 2 line concentrator. The switch storage unit 121 stores startup-registered user information 101 and post-startup-registered user information 102. The startup-registered user information 101 is information synchronized with the PON user information 100. The post-startup-registered user information 102 is information other than the startup-registered user information 101 in the user information (second user information) stored in the switch storage unit 121 of the line concentrator 12a that is in cold standby.

[0030] 4 is a diagram showing examples of startup-registered user information 101 (first database) and post-startup registered user information 102 (second database) in the first embodiment. In some cases, the number of registered conversion devices 50a registered in the PON user information 100 (first user information) is less than the number of registered conversion devices 50a registered in the user information (second user information) stored in the switch storage unit 121 of the line concentrator switch 12a in cold standby mode.

[0031] In this case, the synchronization unit 124 divides the user information (second user information) stored in the switch memory unit 121 of the concentrator switch 12a that is in cold standby into startup registered user information 101 synchronized with the PON user information 100, and post-startup registered user information 102.

[0032] In the startup-registered user information 101, the "user ID" registered in the PON user information 100 is associated with the "VLAN, etc." The "VLAN, etc." is, for example, VLAN identification information (VLAN ID). In the post-startup registered user information 102, the "user ID" of the conversion device 50a that communicates with the PON interface 11 is associated with the "VLAN, etc."

[0033] Returning to Fig. 2, the description of the OLT 10a will continue. The switch control unit 122 controls the operation of each functional unit of the line concentration switch 12a. The synchronization unit 124 acquires the PON user information 100. The synchronization unit 124 determines the startup registered user information 101 and the post-startup registered user information 102, which are synchronized with the PON user information 100.

[0034] At the time of startup from cold standby, the synchronization unit 124 uses the registration unit 125 to register the startup-registered user information 101 in the switch transfer unit 123. After startup from cold standby, the synchronization unit 124 uses the registration unit 125 to register the post-startup registered user information 102 in the switch transfer unit 123.

[0035] When starting up from cold standby, the registration unit 125 registers the startup-registered user information 101 acquired from the synchronization unit 124 in the switch transfer unit 123. After starting up from cold standby, the registration unit 125 registers the post-startup registered user information 102 acquired from the synchronization unit 124 in the switch transfer unit 123.

[0036] The switch forwarding unit 123 performs Layer 2 forwarding of the main signal of the conversion device 50a registered in the PON user information 100 based on the startup registered user information 101 synchronized with the PON user information 100. The switch forwarding unit 123 also performs Layer 2 forwarding of the main signal of the conversion device 50a registered in the post-startup registered user information 102 (the conversion device 50a not registered in the PON user information 100) based on the post-startup registered user information 102.

[0037] The OLT control unit 13a controls the connection state between the upper network 60 and the plurality of concentrator switches 12a based on information that affects the amount of communication between the upper network 60 and the plurality of concentrator switches 12a. The information that affects the amount of communication between the upper network 60 and the plurality of concentrator switches 12a is, for example, the amount of traffic at the ports of the concentrator switches 12a.

[0038] Next, an operation example of the communication system 1a will be described. Fig. 5 is a flowchart showing an operation example of the communication system 1a (high-speed startup mode from cold standby of the line concentrator switch 12a) in the first embodiment. The PON control unit 112 transmits PON user information 100 to the synchronization unit 124 (step S101). The synchronization unit 124 acquires the PON user information 100 (step S102).

[0039] The synchronization unit 124 determines the startup-registered user information 101 and the post-startup-registered user information 102 synchronized with the PON user information 100 (step S103). Upon startup from cold standby, the synchronization unit 124 registers the startup-registered user information 101 in the switch transfer unit 123 using the registration unit 125 (step S104). After startup from cold standby, the synchronization unit 124 registers the post-startup-registered user information 102 in the switch transfer unit 123 using the registration unit 125 (step S105).

[0040] As described above, the PON interface 11 (interface) accommodates communications of each conversion device 50a (each user device) registered in the PON user information 100 (first user information). The switch forwarding unit 123 (forwarding unit) forwards signals between the PON interface 11 and the higher-level device 61 based on second user information including the PON user information 100. The second user information includes startup-registered user information 101 and post-startup registered user information 102, which are information synchronized with the PON user information 100.

[0041] If the number of conversion devices 50a registered in the PON user information 100 (first user information) is less than the number of conversion devices 50a registered in the second user information in the switch transfer unit 123 (transfer unit) that is in cold standby, the synchronization unit 124 separates the second user information into startup-registered user information 101 and post-startup registered user information 102. The synchronization unit 124 registers the startup-registered user information 101, which is information synchronized with the PON user information 100, in the switch transfer unit 123 upon startup from cold standby.

[0042] In this way, each conversion device 50a registered in the PON user information 100 can be made to communicate in a short time from cold standby, thereby shortening the startup time of the line concentrator switch 12a from cold standby.

[0043] After startup from cold standby, the synchronization unit 124 registers, in the switch forwarding unit 123, post-startup registered user information 102, which is information in the second user information other than the startup registered user information 101. This makes it possible to reduce the power consumption of the OLT 10a while avoiding a deterioration in the communication quality of each conversion device 50a (each ONU).

[0044] (First Modification) Each concentrator switch 12a may be provided with a lighting device (not shown) or a display device (not shown). When activated in the fast startup mode, each concentrator switch 12a may light up or blink the lighting device. Furthermore, each concentrator switch 12a may display on the display device that it has activated in the fast startup mode. This allows a maintenance person near each concentrator switch 12a to visually confirm whether or not each concentrator switch 12a has activated in the fast startup mode.

[0045] (Second Modification) The OLT control unit 13a may notify the OLT operation unit 20 that each line concentrator 12a has started up in the fast startup mode. The OLT operation unit 20 displays on the console that each line concentrator 12a has started up in the fast startup mode. This allows a maintenance person located remotely from each line concentrator 12a to check on the console whether each line concentrator 12a has started up in the fast startup mode.

[0046] Second Embodiment In the second embodiment, the main difference from the first embodiment is that the OLT control unit registers the startup registered user information in the switch forwarding unit. In the second embodiment, the difference from the first embodiment will be mainly described.

[0047] 6 is a diagram showing an example of the configuration of a communication system 1b in the second embodiment. The communication system 1b includes an OLT 10b, an OLT operation unit 20, an upper network operation unit 30, K optical splitters 40, a plurality of conversion devices 50b, and L upper networks 60. The OLT 10b includes K PON interfaces 11, M line concentrator switches 12b, and an OLT control unit 13b.

[0048] The OLT control unit 13b controls the startup of the switch transfer unit 123 from cold standby and the transition to cold standby of the switch transfer unit 123. When the switch transfer unit 123 starts up from cold standby, the OLT control unit 13b registers startup-registered user information in the switch transfer unit 123. After the switch transfer unit 123 starts up from cold standby, the OLT control unit 13b registers post-startup registered user information in the switch transfer unit 123.

[0049] 7 is a diagram showing an example of the configuration of the PON interface 11, the line concentrator 12b, and the OLT control unit 13b in the second embodiment. The PON interface 11 includes a PON storage unit 111, a PON control unit 112, and a PON transfer unit 113.

[0050] The line concentrator 12b includes a switch control unit 122 and a switch forwarding unit 123. The switch control unit 122 includes a registration unit 125.

[0051] The OLT control unit 13b includes a synchronization unit 131 and an OLT storage unit 132. The OLT storage unit 132 stores startup registered user information 101, post-startup registered user information 102, and PON user information 103.

[0052] The synchronization unit 131 acquires the PON user information 100 from the PON control unit 112. The synchronization unit 131 determines startup-registered user information 101 and post-startup-registered user information 102 synchronized with the PON user information 100. That is, the synchronization unit 131 divides the PON user information 103 stored in the OLT storage unit 132 for the line concentrator switch 12b that is in cold standby into startup-registered user information 101 and post-startup-registered user information 102 based on the PON user information 100.

[0053] When starting up from cold standby, the synchronization unit 131 transmits the startup-registered user information 101 to the registration unit 125. After starting up from cold standby, the synchronization unit 131 transmits the post-startup registered user information 102 to the registration unit 125.

[0054] When starting up from cold standby, the registration unit 125 registers the startup-registered user information 101 in the switch transfer unit 123. After starting up from cold standby, the registration unit 125 registers the post-startup registered user information 102 in the switch transfer unit 123.

[0055] Next, an operation example of the communication system 1b will be described. Fig. 8 is a flowchart showing an operation example of the communication system 1b in the second embodiment. The PON control unit 112 transmits the PON user information 100 to the synchronization unit 131 (step S201). The synchronization unit 131 acquires the PON user information 100 (step S202). The synchronization unit 131 determines the startup-registered user information 101 and the post-startup registered user information 102 synchronized with the PON user information 100 (step S203).

[0056] Upon startup from cold standby, the synchronization unit 131 transmits the startup-registered user information 101 to the registration unit 125 (step S204). The registration unit 125 registers the startup-registered user information 101 in the switch forwarding unit 123 (step S205). After startup from cold standby, the synchronization unit 131 transmits the post-startup registered user information 102 to the registration unit 125 (step S206). The registration unit 125 registers the post-startup registered user information 102 in the switch forwarding unit 123 (step S207).

[0057] As described above, when the number of registrations of each conversion device 50b registered in the PON user information 100 (first user information) is smaller than the number of registrations of each conversion device 50b registered in the second user information in the switch transfer unit 123 (transfer unit) that is in cold standby, the synchronization unit 131 divides the second user information into startup-registered user information 101 and post-startup registered user information 102. The synchronization unit 131 registers the startup-registered user information 101, which is information synchronized with the PON user information 100, in the switch transfer unit 123 upon startup from cold standby.

[0058] This makes it possible to reduce the startup time of the line concentrator switch 12b from cold standby.

[0059] (Third Embodiment) In the third embodiment, the main difference from the second embodiment is that the OLT control unit registers startup registration user information based on PON user information and ONU authentication information in the switch forwarding unit. In the third embodiment, the differences from the second embodiment will be mainly described.

[0060] 9 is a diagram showing an example of the configuration of a communication system 1c according to the third embodiment. The communication system 1c includes an OLT 10c, an OLT operation unit 20, an upper network operation unit 30, K optical splitters 40, a plurality of conversion devices 50c, and L upper networks 60. The OLT 10c includes K PON interfaces 11, M line concentrator switches 12b, and an OLT control unit 13c.

[0061] The OLT control unit 13c controls the startup of the switch transfer unit 123 from cold standby and the transition to cold standby of the switch transfer unit 123. When the switch transfer unit 123 starts up from cold standby, the OLT control unit 13c registers startup-registered user information in the switch transfer unit 123. After the switch transfer unit 123 starts up from cold standby, the OLT control unit 13c registers post-startup registered user information in the switch transfer unit 123.

[0062] 10 is a diagram showing an example of the configuration of the PON interface 11, the line concentrator 12c, and the OLT control unit 13c in the third embodiment. The PON interface 11 includes a PON storage unit 111, a PON control unit 112, and a PON forwarding unit 113. The line concentrator 12c includes a switch control unit 122 and a switch forwarding unit 123. The switch control unit 122 includes a registration unit 125.

[0063] The OLT control unit 13c includes a synchronization unit 131 and an OLT storage unit 132. The OLT storage unit 132 stores startup registered user information 101, post-startup registered user information 102, PON user information 103, and ONU authentication information 105.

[0064] The PON storage unit 111 stores PON user information 100 and ONU authentication information 104. The ONU authentication information is information related to the authentication of the conversion device 50c. The ONU authentication information may include, for example, the MAC address (identification information) of the authenticated conversion device 50c. The PON control unit 112 transmits the PON user information 100 and the ONU authentication information 104 to the synchronization unit 131.

[0065] The synchronization unit 131 determines for each conversion device 50c whether the conversion device 50c is authenticated in the ONU authentication information 104. For example, the MAC address of each conversion device 50c is pre-registered in the OLT storage unit 132. When authenticating a conversion device 50c, the synchronization unit 131 acquires the MAC address of the conversion device 50c from the PON control unit 112 based on the Multipoint Control Protocol (MPCP). The synchronization unit 131 compares the MAC address pre-registered in the OLT storage unit 132 with the MAC address acquired from the conversion device 50c. The synchronization unit 131 determines that the conversion device 50c that transmitted the MAC address pre-registered in the OLT storage unit 132 is an authenticated conversion device 50c. In this way, the synchronization unit 131 determines the ONU authentication information 105 including identification information of the authenticated conversion device 50c.

[0066] The synchronization unit 131 acquires the PON user information 100. The synchronization unit 131 determines startup-registered user information 101 and post-startup-registered user information 102 that are synchronized with the PON user information 100 and the ONU authentication information 104. That is, the synchronization unit 131 divides the PON user information 103 stored in the OLT storage unit 132 for the line concentrator switch 12c that is in cold standby into the startup-registered user information 101 and the post-startup-registered user information 102 based on the PON user information 100 and the ONU authentication information 104.

[0067] When starting up from cold standby, the synchronization unit 131 transmits the startup-registered user information 101 to the registration unit 125. After starting up from cold standby, the synchronization unit 131 transmits the post-startup registered user information 102 to the registration unit 125.

[0068] When starting up from cold standby, the registration unit 125 registers the startup-registered user information 101 in the switch transfer unit 123. After starting up from cold standby, the registration unit 125 registers the post-startup registered user information 102 in the switch transfer unit 123.

[0069] Next, an example of operation of the communication system 1c will be described. Fig. 11 is a flowchart showing an example of operation of the communication system 1c in the third embodiment. The PON control unit 112 transmits the PON user information 100 and the ONU authentication information 104 to the synchronization unit 131 (step S301). The synchronization unit 131 acquires the PON user information 100 and the ONU authentication information 104 (step S302). The synchronization unit 131 determines the startup-registered user information 101 and the post-startup registered user information 102 synchronized with the PON user information 100 and the ONU authentication information 104 (step S303).

[0070] Upon startup from cold standby, the synchronization unit 131 transmits the startup-registered user information 101 to the registration unit 125 (step S304). The registration unit 125 registers the startup-registered user information 101 in the switch forwarding unit 123 (step S305). After startup from cold standby, the synchronization unit 131 transmits the post-startup registered user information 102 to the registration unit 125 (step S306). The registration unit 125 registers the post-startup registered user information 102 in the switch forwarding unit 123 (step S307).

[0071] As described above, the synchronization unit 131 determines the startup-registered user information 101 based on the PON user information 100 and the ONU authentication information 104. The synchronization unit 131 registers the startup-registered user information 101, which is information based on the PON user information 100 and the ONU authentication information 104, in the switch forwarding unit 123 upon startup from cold standby. That is, the synchronization unit 131 registers the startup-registered user information 101, which is synchronized with the identification information of each authenticated conversion device 50c and the PON user information 100, in the switch forwarding unit 123 upon startup from cold standby.

[0072] This makes it possible to reduce the startup time of the line concentrator switch from cold standby.

[0073] (Variation of the Third Embodiment) <Priority Registration Based on Power Supply State> The synchronization unit 131 acquires a “Dying Gasp” signal from each conversion device 50 c (each ONU) via the PON transfer unit 113 and the PON control unit 112. Based on the acquired “Dying Gasp” signal, the synchronization unit 131 determines, for each conversion device 50 c, whether the power supply of the conversion device 50 c that transmitted the “Dying Gasp” signal is on or off.

[0074] When the power supply of the conversion device 50c is turned off, the conversion device 50c uses the power stored in the capacitor of the conversion device 50c to transmit an information OAM (Operations, Administration, Maintenance) frame (Information OAM frame (Dying Gasp)) to the PON interface 11 (Reference 1: "Setting Dying Gasp," [online], [searched on August 29, 2023], Internet) <URL: https: / / www.cisco.com / c / ja_jp / td / docs / switches / lan / catalyst1000 / software / releases / 15_2_7_e / configuration_guides / sys_mgmt / b_1527e_sys_mgmt_c1000_cg / m_sm_configuring_dying_gasp.pdf> ).

[0075] If communication with the conversion device 50c for the user information becomes possible in the order in which the user information is registered in the switch transfer unit 123, the synchronization unit 131 and the registration unit 125 may give priority to registering the user information of the conversion device 50c that is powered on in the switch transfer unit 123.

[0076] <Priority Registration Based on Priority Frame> When a specific communication service is provided to a user, the conversion device 50c may transmit a priority frame of that communication service to the PON interface 11. The priority frame is, for example, a Media Access Control (MAC) frame. The synchronization unit 131 identifies the conversion device 50c that transmitted the priority frame based on the top three bits of the ToS (type of service) field in the IP (Internet Protocol) header of the MAC frame. The synchronization unit 131 and the registration unit 125 may prioritize and register the user information of the conversion device 50c that transmitted the priority frame in the switch forwarding unit 123.

[0077] The synchronization unit 131 may identify priority frames based on the class of service (CoS) value of the VLAN. The conversion device 50c assigns the ToS value of the MAC frame to the VLAN and copies it to the CoS value, and the PON forwarding unit 113 and the switch forwarding unit 123 prioritize upstream signals based on the CoS value. The conversion device 50c also deletes the VLAN CoS value from downstream signals that have been prioritized based on the VLAN CoS value.

[0078] <Priority Registration Based on Communication Volume> The synchronization unit 131 and the registration unit 125 may prioritize user information of conversion devices 50c with high communication volumes and register it in the switch forwarding unit 123. The synchronization unit 131 measures the communication volume (number of MAC frames and length of each MAC frame) for each conversion device 50c (for each VLAN). The synchronization unit 131 identifies conversion devices 50c with communication volumes greater than the measured communication volume.

[0079] (Fourth Embodiment) In the fourth embodiment, the main difference from the first to third embodiments is that user information registered at startup is registered in a switch transfer unit provided in an optical subscriber line aggregation device. In the fourth embodiment, the differences from the first to third embodiments will be mainly described.

[0080] 12 is a diagram showing an example of the configuration of a communication system 1d in the fourth embodiment. The communication system 1d includes an OLT 10d, an OLT operation unit 20, an upper network operation unit 30, a plurality of conversion devices 50d, and L upper networks 60. A collection device 70 is connected to the conversion device 50d. A plurality of modems 80 are connected to the collection device 70. A control line may be provided between the conversion device 50d and the OLT 10d.

[0081] The OLT 10d includes K interfaces 14, M line concentrators 12d, and an OLT control unit 13d. The interfaces 14 are media converters (MC). A plurality of conversion devices 50d are connected to the interfaces 14 via optical fibers. The interfaces 14 convert electrical signals input from the line concentrators 12d into optical signals. The interfaces 14 convert optical signals input from the conversion devices 50d into electrical signals.

[0082] The conversion device 50d is a media converter. The conversion device 50d converts the electrical signal input from the aggregation device 70 into an optical signal. The conversion device 50d converts the optical signal input from the optical splitter 40 into an electrical signal.

[0083] The concentrator 70 is a very high bitrate digital subscriber line (VDSL) concentrator, and is installed in, for example, an apartment building, etc. The modem 80 is, for example, a VDSL modem.

[0084] 13 is a diagram showing an example of the configuration of a concentrator device 70 in the fourth embodiment. The concentrator device 70 includes a concentrator 71 and a switch 72. The concentrator 71 includes a DSLAM (Digital Subscriber Line Access Multiplexer) storage unit 711, a DSLAM control unit 712, and a VDSL forwarding unit 713. The switch 72 includes a switch storage unit 721, a switch control unit 722, and a switch forwarding unit 723. The switch control unit 722 includes a synchronizing unit 724 and a registering unit 725.

[0085] The aggregation unit 71 is a functional unit that aggregates the digital subscriber lines of multiple modems 80. The DSLAM storage unit 711 stores DSLAM user information 106. The DSLAM user information 106 includes "user ID," which is identification information for the DSLAM user device. The user device identification information is identification information for the modem 80. The DSLAM user information may also register the guaranteed bandwidth and maximum bandwidth of the modem 80 in association with the "user ID," which is identification information for the user device.

[0086] The DSLAM control unit 712 controls the operation of the aggregation unit 71. The DSLAM control unit 712 transmits DSLAM user information 106 to the synchronization unit 724. The VDSL transfer unit 713 transfers the electrical signal transmitted from the modem 80 to the switch transfer unit 723. The VDSL transfer unit 713 transfers the electrical signal transmitted from the switch transfer unit 723 to the modem 80.

[0087] The switch 72 is a Layer 2 switch. The switch storage unit 721 stores startup-registered user information 107 and post-startup-registered user information 108. The startup-registered user information 107 is information synchronized with the DSLAM user information 106. The post-startup-registered user information 108 is information other than the startup-registered user information 107 in the user information (second user information) stored in the switch storage unit 721 of the switch 72 that is in cold standby mode.

[0088] The switch control unit 722 controls the operation of each functional unit of the line concentrator switch 12 d. The synchronization unit 724 may detect that the number of registered modems 80 in the DSLAM user information 106 (first user information) is less than the number of registered modems 80 in the user information (second user information) stored in the switch storage unit 721 of the switch 72 that is in cold standby.

[0089] In this case, the synchronization unit 724 divides the user information (second user information) stored in the switch memory unit 721 of the line concentration switch 12a that is in cold standby into startup registered user information 107 synchronized with the DSLAM user information 106, and post-startup registered user information 108.

[0090] At the time of startup from cold standby, the synchronization unit 724 uses the registration unit 725 to register the startup-registered user information 107 in the switch transfer unit 723. After startup from cold standby, the synchronization unit 724 uses the registration unit 725 to register the post-startup registered user information 108 in the switch transfer unit 723.

[0091] At the time of startup from cold standby, the registration unit 725 registers the startup registered user information 107 acquired from the synchronization unit 724 in the switch transfer unit 723. After startup from cold standby, the registration unit 725 registers the post-startup registered user information 108 acquired from the synchronization unit 724 in the switch transfer unit 723.

[0092] The switch forwarding unit 723 performs Layer 2 forwarding of main signals of modems 80 registered in the DSLAM user information 106 based on startup registered user information 107 synchronized with the DSLAM user information 106. The switch forwarding unit 723 also performs Layer 2 forwarding of main signals of modems 80 registered in post-startup registered user information 108 (modems 80 not registered in the DSLAM user information 106) based on the post-startup registered user information 108.

[0093] Next, an example of operation of the communication system 1d will be described. Fig. 14 is a flowchart showing an example of operation of the communication system 1d in the fourth embodiment. The DSLAM control unit 712 transmits the DSLAM user information 106 to the synchronization unit 724 (step S401). The synchronization unit 724 acquires the DSLAM user information 106 (step S402).

[0094] The synchronization unit 724 determines the startup-registered user information 107 and the post-startup-registered user information 108 that are synchronized with the DSLAM user information 106. That is, the synchronization unit 724 divides the user information stored in the switch storage unit 721 of the switch 72 that is in cold standby into the startup-registered user information 107 and the post-startup-registered user information 108 based on the DSLAM user information 106 (step S403).

[0095] When starting up from cold standby, the synchronization unit 724 uses the registration unit 725 to register the startup-registered user information 107 in the switch transfer unit 723 (step S404). After starting up from cold standby, the synchronization unit 724 uses the registration unit 725 to register the post-startup registered user information 108 in the switch transfer unit 723 (step S405).

[0096] As described above, the second user information may include startup-registered user information 107, which is information synchronized with the DSLAM user information 106, and post-startup registered user information 108. If the number of registered modems 80 registered in the DSLAM user information 106 (first user information) is less than the number of registered modems 80 registered in the second user information in the switch forwarding unit 723 (forwarding unit) that has gone into cold standby, the synchronizing unit 724 separates the second user information into startup-registered user information 107 and post-startup registered user information 108. The synchronizing unit 724 registers the startup-registered user information 107, which is information synchronized with the DSLAM user information 106, in the switch forwarding unit 723 upon startup from cold standby.

[0097] In this way, each modem 80 registered in the DSLAM user information 106 can be made to communicate in a short time from cold standby, thereby shortening the startup time of the aggregation device 70 from cold standby.

[0098] Furthermore, the synchronization unit 724 registers the post-startup registered user information 108, which is information other than the startup registered user information 107 in the second user information, in the switch transfer unit 723 after startup from cold standby.

[0099] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0100] The present invention is applicable to optical communication systems (optical access networks).

[0101] 1a, 1b, 1c, 1d...Communication system, 10a, 10b, 10c, 10d...OLT, 11...PON interface, 12a, 12b, 12c, 12d...Line concentrator switch, 13a, 13b, 13c, 13d...OLT control unit, 14...Interface, 20...OLT operation unit, 30...Higher-level network operation unit, 40...Optical splitter, 50a, 50b, 50c, 50d...Conversion device, 60...Higher-level network, 61...Higher-level device, 70...Concentrator, 71...Concentrator unit, 72...Switch, 80...Modem, 100...PON user information, 101...User information registered at startup, 102 ...user information registered after startup, 103...PON user information, 104...ONU authentication information, 105...ONU authentication information, 106...DSLAM user information, 111...PON storage unit, 112...PON control unit, 113...PON forwarding unit, 121...switch storage unit, 122...switch control unit, 123...switch forwarding unit, 124...synchronization unit, 125...registration unit, 131...synchronization unit, 132...OLT storage unit, 711...DSLAM storage unit, 712...DSLAM control unit, 713...VDSL forwarding unit, 721...switch storage unit, 722...switch control unit, 723...switch forwarding unit, 724...synchronization unit, 725...registration unit

Claims

1. A communications system comprising: an interface that accommodates communications of each user device registered in first user information; a transfer unit that transfers signals between a higher-level device and an interface, based on second user information including the first user information; and a synchronization unit that, when the number of registered user devices registered in the first user information is less than the number of registered user devices registered in the second user information in the transfer unit that has gone into cold standby, registers startup-time registered user information, which is information synchronized with the first user information, in the transfer unit upon startup from the cold standby.

2. A communication system as described in claim 1, wherein the synchronization unit registers the startup-registered user information synchronized with the identification information of each authenticated user device and the first user information in the transfer unit upon startup from the cold standby.

3. The communication system according to claim 1, wherein the synchronization unit registers, in the transfer unit after startup from the cold standby, post-startup registered user information, which is information in the second user information other than the startup-time registered user information.

Images