JP2010034877A - Redundant transmission system in point-to-multipoint system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a redundant transmission system of an economical PON system by utilizing the band of a spare transmission line system even at usual time. <P>SOLUTION: A center side apparatus (OLT) is provided with a pair of OLTPON terminating parts, a pair of optical transmission/reception parts of different wavelength sets of transmission/reception wavelengths, a pair of optical wavelength demultiplex part for demultiplexing the communication wavelength of each optical transmitter-receiver, and a dynamic SW part for performing the switching control of a transmission line system. A subscriber side apparatus (ONU) is provided with a pair of ONUPON terminating parts, a pair of optical transmission/reception parts communicable using the wavelength of the wavelength set, a pair of optical wavelength demultiplex part for demultiplexing the wavelength of the wavelength set, and a dynamic SW part for performing the switching control of the transmission line system. Between the OLT and the ONU, the wavelength set to be communicated is selected in an ONU unit and the transmission line system is switched. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a redundant transmission system in a point-multipoint system in an optical subscriber network via an optical branching element, that is, an optical splitter.

  Regarding the redundant system of the passive optical network (PON) system, the standard recommendation is made in Non-Patent Document 1 and Non-Patent Document 2, but the development of a redundant system that improves these has been actively conducted so far. Yes.

  FIG. 39 is a configuration example of a passive optical network (PON) system having a conventional redundancy function according to Patent Document 1 and Patent Document 2. The optical transmission line system # 0 connects the optical transmission / reception unit # 0 of the subscriber unit (ONU) and the optical transmission / reception unit # 0 of the center side device (OLT). On the other hand, the optical transmission line system # 1 connects the ONU transceiver unit # 1 and the OLT transceiver unit # 1. When a failure occurs in the optical transmission line system # 0, switching to the optical transmission line system # 1 is performed by the ONU system switching SW unit and the OLT system switching SW unit. However, with this technology, even if the transmitter / receiver # 0 of a specific ONU fails or when a failure such as disconnection occurs in a specific ONU section from the splitter, all systems accommodated in the same transmission line system It is necessary to switch to another transmission line system, and a system that is not affected by a failure is also subject to switching. In the example of FIG. 39, the ONU # 2 has to switch the transmission path system due to the failure of the ONU # 1. In such system switching, it is necessary to perform switching after confirming the normality of all systems accommodated in the same transmission path system in order to determine whether the fault is an ONU unit fault or a fault across multiple ONUs. Yes, as the number of accommodated ONUs increases, it takes time for switching. Further, since the distance between the OLT and the ONU varies depending on the transmission line system, the ranging process for PON signal control (Ranging process of ITU-TG.983.1, Auto Discover process of IEEE Std802.3ah, etc.) is performed again. To register all ONUs again. Further, since the standby transmission line system is a cold standby for when a failure occurs, it is not normally used and is uneconomical. Furthermore, if non-redundant ONUs that do not require a redundant configuration are accommodated in the same PON, communication disconnection occurs due to switching of redundant ONUs, and the ONUs must be manually reconnected to the standby system. Therefore, it is impossible to accommodate non-redundant ONUs at the same time.

  FIG. 40 is a configuration example of a PON system according to Patent Document 3 in which a transmission path system can be selected for each ONU. A new ONU registration control unit is implemented in the OLT, and a branch coupling unit is implemented in place of the system switching SW unit. An ONU registration switching control unit is mounted on the ONU. In the ONU, when a failure occurs, an abnormal signal of the received signal is notified from the PON termination unit to the ONU registration switching control unit, and the system switching SW unit switches from the optical transmission line in which the failure has occurred to another optical transmission line. Do. The ONU registration switching control unit initializes ONU registration to the PON termination unit, makes a transition to an unregistered state, and waits for ranging processing and registration processing from the OLT. On the other hand, in the OLT, when a failure is detected in the PON termination unit, the PON termination unit notifies the ONU registration control unit of an abnormality in the received signal, initializes registration for each corresponding ONU, and transitions to an unregistered state. Start the ranging process and registration process. If forced switching is required, a forced switching signal is transmitted from the operation system or the like to the OLT, and further, the switching can be executed on an ONU basis by notifying the ONU of registration initialization. Further, the branch coupling unit in the OLT simply joins and distributes the signals of the respective optical transmission / reception units constituting the system, and does not require special electrical signal conversion or signal position timing adjustment. Therefore, it is an inexpensive device. However, this technique is also uneconomical because a spare transmission line system is not used at normal times. In addition, since the ranging process is performed, the switching time becomes long.

FIG. 41 is an example in which switching is performed in an upper layer using a dynamic SW unit such as ATMSW or L2SW according to Patent Document 4. FIG. 41 describes a case where L2SW is applied. In this method, bandwidths are secured in advance in transmission path system # 0 and transmission path system # 1, and when a failure occurs, the upper layer path (for example, VLAN ID unit) is switched using the dynamic SW unit. In the example of the figure, the paths of VLAN # 10 and VLAN # 20 are set for the PON system of transmission path system # 0, and the paths of VLAN # 11 and VLAN # 21 are set for the PON system of transmission path system # 1. It is set. In the case of this method, only the system affected by the failure is subject to switching. Further, since ONUs are registered in advance in the systems of the two PON systems, the ranging process associated with switching is not necessary, and the problems pointed out in Patent Documents 1 to 3 do not occur. However, it is necessary to operate the two PON systems in parallel, and it is necessary to reserve a band for switching in a spare transmission line system in advance. Therefore, it can be said that this technique is also uneconomical because the spare transmission line system is not normally used.
JP-A-8-242207 JP 2004-96734 A JP 2006-180422 A JP 2002-218008 A ITU-T G.983.5, SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS, Digital sections and digital line system-Optical line systems for local and access networks, A broadband optical access system with enhanced survivability ITU-T G.984.1, S ERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS, Digital sections and digital line system-Optical line systems for local and access networks, General characteristics for Gigabit-capable Passive Optical Networks (GPON) ITU-T I.630, SERIES I: INTEGRATED SERVICES DIGITAL NETWORK, Maintenance principles, ATM protection switching ITU-T G.8031 / Y.1342, SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS ANDNETWORKS, Ethernet (registered trademark) over Transport aspects-General aspect, SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS , Internet protocol aspect-Transport, Ethernet Protection Switching

  In the case of a conventional PON system having a redundant configuration, a spare transmission line system that is not normally used for communication is a spare PON termination unit, an optical transmission / reception unit in the OLT, and a feeder section from the OLT to the optical branching device. It was uneconomical because fiber installation was necessary.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a redundant transmission system in an economical PON system by utilizing a band of a spare transmission line system even in a normal time. Yes.

  In order to achieve the above object, the present invention includes a center side device (OLT) and a plurality of subscriber side devices (ONUs) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium. In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission between an OLT and an ONU via a plurality of optical transmission paths, the OLT includes a pair of OLTPON termination units, A pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the communication wavelengths of each optical transmitter / receiver, and OLT switching control means for performing transmission path system switching control The ONU includes a pair of optical wavelength demultiplexing units that demultiplex the wavelengths of the wavelength set, an optical transceiver that can communicate using the wavelengths of the wavelength set, an ONUPON termination unit, It includes an ONU switching control means for switching control of the feed path system, between the said OLT ONU, select the wavelength set that communicates the ONU unit, and performs switching of transmission line system.

  The present invention also includes a center side device (OLT) and a plurality of subscriber side devices (ONUs) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of optical transmissions. In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission between an OLT and an ONU via a path, the OLT includes a pair of OLTPON termination units and a wavelength set of transmission / reception wavelengths. A pair of optical transmission / reception units having different wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength set, management of active and standby connection information set for each wavelength set unit, active and standby A higher layer dynamic SW unit for controlling the switching of the connection, and the ONU is a pair of optical transmission / reception different from the pair of ONUPON termination units in the wavelength set of transmission / reception wavelengths A pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength set, and management of current and backup connection information set for each wavelength set unit and switching control of current and backup connections The layer includes a dynamic SW unit, the OLTPON termination unit and the ONUPON termination unit always communicate with each wavelength set unit, and the OLT side dynamic SW unit and ONU side dynamic SW unit set for each wavelength set unit. By performing switching control between active and backup connections, a wavelength set to be communicated is selected in units of ONUs, and failure recovery is performed.

  The present invention also includes a center side device (OLT) and a plurality of subscriber side devices (ONUs) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of optical transmissions. In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission between an OLT and an ONU via a path, the OLT includes a pair of OLTPON termination units and a wavelength set of transmission / reception wavelengths. A pair of optical transmission / reception units having different wavelengths, a pair of optical wavelength demultiplexing units for demultiplexing wavelengths of the wavelength set, and ONUs that manage ONUs belonging to each OLTPON termination unit and perform system switching control in the OLT A registration control unit, wherein the ONU demultiplexes the non-redundant ONUPON termination unit, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, and wavelengths of the wavelength sets A pair of optical wavelength multiplexing / demultiplexing units, an ONTU registration switching control unit that performs management of the OLPON termination unit to which the own ONU belongs and system switching control in the ONU, and a system switching electrical SW unit, and the OLTPON termination unit and the ONUPON When the termination unit communicates via any wavelength set wavelength, and the ONU registration switching control unit of the ONU receives the reception signal abnormal signal, the switching of the system switching electrical SW unit and the switching destination ONU-side optical transmission / reception unit of the ONU side optical transmission / reception unit, optical transmission stop of the transmission wavelength of the switching source ONU-side optical transmission / reception unit, registration control for the switching destination OLTPON termination unit, and ONU registration control of the OLT By receiving a signal notifying that the reception signal abnormality signal or the registration request from the ONU has been received from the OLTPON termination unit. A registration deletion control in the switching source OLTPON termination for, by performing the registration control in OLTPON end of the switching destination, select the wavelength set that communicates the ONU unit, and performs error recovery.

  In the redundant transmission system, the wavelength set may have the same upstream signal wavelength and different downstream signal wavelengths.

  The present invention also includes a center side device (OLT) and a plurality of subscriber side devices (ONUs) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of optical transmissions. In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission between an OLT and an ONU via a path, the OLT includes a pair of OLTPON termination units and a wavelength set of transmission / reception wavelengths. A pair of optical transmission / reception units having different wavelengths, a pair of optical wavelength demultiplexing units for demultiplexing wavelengths of the wavelength set, and ONUs that manage ONUs belonging to each OLTPON termination unit and perform system switching control in the OLT A pair of optical wavelengths for demultiplexing the wavelengths of the wavelength set and a non-redundant ONUPON termination unit; a non-redundant wavelength tunable optical transceiver unit; A demultiplexing unit, an ONU registration switching control unit that performs management of the OLTPON termination unit to which the own ONU belongs and system switching control in the ONU, and a system switching optical SW unit, and the OLTPON termination unit and the ONUPON termination unit are either The ONU registration switching control unit of the ONU communicates via wavelengths in units of wavelength sets, and receives a reception signal abnormal signal, thereby corresponding to the wavelength set of the switching destination OLTPON termination unit in the wavelength tunable optical transmission / reception unit The wavelength conversion of the transmission wavelength, the switching of the system switching light SW unit, and the registration control for the switching destination OLTPON termination unit are performed, and the ONT registration control unit of the OLT receives the received signal abnormal signal or the signal from the OLTPON termination unit. By receiving a signal notifying that the registration request from the ONU has been received, the switching source OLTPO for the corresponding ONU A registration deletion control in the terminal unit, by performing the registration control in OLTPON end of the switching destination, select the wavelength set that communicates the ONU unit, and performs error recovery.

  The present invention also includes a center side device (OLT) and a plurality of subscriber side devices (ONUs) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of optical transmissions. In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission between an OLT and an ONU via a path, the OLT includes a pair of OLTPON termination units and an upstream signal wavelength. Management of ONUs belonging to a pair of optical transmission / reception units that are the same and differ only in the wavelength of the downstream signal, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the communication wavelengths of each optical transmitter / receiver, and each OLTPON termination unit And an ONU registration control unit that performs system switching control in the OLT, and the ONU includes a non-redundant ONUPON termination unit, a non-redundant optical transmission / reception unit that differs only in reception wavelength, and a communication wave of the optical transceiver A pair of optical wavelength demultiplexing units for demultiplexing, an ONTU registration switching control unit for performing management of the OLTPON termination unit to which the own ONU belongs and system switching control in the ONU, and a system switching optical SW unit, When the termination unit and the ONUPON termination unit communicate with each other through a wavelength in any wavelength set unit, and the ONU registration switching control unit of the ONU receives the reception signal abnormal signal, the switching of the system switching optical SW unit is performed. And the OLT ONU registration control unit of the OLT receives a signal notifying that the reception signal abnormality signal or the registration request from the ONU has been received from the OLTPON termination unit. Therefore, the registration deletion control at the switching source OLTPON termination unit and the registration at the switching destination OLTPON termination unit for the corresponding ONU By performing the control to select the wavelength set that communicates the ONU unit, and performs error recovery.

  The present invention also relates to a center side device (OLT) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a plurality of subscriber side devices (ONUs) via a plurality of optical transmission paths. A pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and for each wavelength set unit A higher-layer dynamic SW unit that performs management of set working and spare connection information and switching control between the working and spare connections is provided. The OLTPON termination unit communicates with the ONU in units of wavelength sets, and By switching and controlling the working and backup connections set by the SW unit for each wavelength set unit, the wavelength set for communication is selected for each ONU unit, and the transmission path system is switched. And wherein the Ukoto.

  The present invention also relates to a center side device (OLT) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a plurality of subscriber side devices (ONUs) via a plurality of optical transmission paths. A pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and each OLTPON termination unit An ONU registration control unit that performs management of ONUs that belong to the system and performs system switching control in the OLT, and notifies that the ONU registration control unit has received a reception signal abnormality signal or a registration request from the ONU from the OLTPON termination unit By receiving the signal to be registered, the registration deletion control at the switching source OLTPON termination unit for the corresponding ONU and the registration at the switching destination OLTPON termination unit are performed. By performing the control to select the wavelength set that communicates the ONU unit, and performs switching of transmission line system.

  In the center side apparatus (OLT), the wavelength set may have the same upstream signal wavelength and different downstream signal wavelengths.

  The present invention also relates to a subscriber side device (ONU) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a center side device (OLT) through a plurality of optical transmission paths. A pair of ONUPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and set for each wavelength set A dynamic SW unit of an upper layer that performs management of current and spare connection information and switching control between current and spare connections is provided, and the ONUPON termination unit communicates with the OLT in units of wavelength sets, and the dynamic SW unit By switching the active and standby connections set for each wavelength set unit, the wavelength set to be communicated can be selected for each ONU unit, and the transmission path system can be switched. The features.

  In addition, the present invention provides a non-contact unit (ONU) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a center side device (OLT) through a plurality of optical transmission paths. A redundant ONUPON termination unit, a pair of optical transmission / reception units with different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and an OLTPON termination unit to which the own ONU belongs Management and switching control within the ONU, and an ONU registration switching control unit and a system switching electrical SW unit, and the ONU registration switching control unit receives the received signal abnormality signal, so that the system switching electrical SW unit Performs switching, optical output start of the transmission wavelength of the switching destination optical transmission / reception unit, optical output stop of the transmission wavelength of the switching source optical transmission / reception unit, and registration control for the switching destination OLTPON termination unit. It allows to select the wavelength set that communicates the ONU unit, and performs switching of transmission line system.

  In the subscriber unit (ONU) system, the wavelength set may have the same upstream signal wavelength but different downstream signal wavelengths.

  In addition, the present invention provides a non-contact unit (ONU) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a center side device (OLT) through a plurality of optical transmission paths. Redundant ONUPON termination unit, non-redundant wavelength tunable optical transmission / reception unit, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength set, management of the OLTPON termination unit to which the own ONU belongs and the ONU An ONU registration switching control unit and a system switching optical SW unit that perform system switching control of the optical switching unit, and when the ONU registration switching control unit receives a reception signal abnormal signal, an OLPON termination of a switching destination in the wavelength tunable optical transceiver unit By performing wavelength conversion of the transmission wavelength corresponding to the wavelength set of the unit, switching of the system switching light SW unit, and registration control for the switching destination OLTPON termination unit. Selects a wavelength set to communicate in ONU unit, and performs switching of transmission line system.

  In addition, the present invention provides a non-contact unit (ONU) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a center side device (OLT) through a plurality of optical transmission paths. A redundant ONUPON termination unit, a non-redundant optical transmission / reception unit that differs only in reception wavelength, a pair of optical wavelength demultiplexing units for demultiplexing the communication wavelength of the optical transceiver, and an OLTPON termination unit to which the own ONU belongs An ONU registration switching control unit that performs management and system switching control in the ONU and a system switching light SW unit are provided. When the ONU registration switching control unit receives a reception signal abnormality signal, the switching of the system switching light SW unit is performed. Then, by performing registration control for the switching destination OLTPON termination unit, a wavelength set to be communicated is selected in units of ONUs, and the transmission path system is switched.

The present invention also relates to a redundant transmission method in a point-multipoint optical transmission system (PON system) that performs signal transmission with a subscriber unit (ONU) via a plurality of optical transmission paths, Between the ONUs, a working path accommodated in the working transmission line system and a protection path accommodated in the spare transmission line system are set using wavelength sets having different transmission and reception wavelengths. It is characterized in that a protection path is selected and switching between the working and protection transmission line systems is performed.
In the wavelength set, the wavelength of the upstream signal may be the same and only the wavelength of the downstream signal may be different.

As described above, according to the present invention, it is economical to use a spare transmission line system that could not be used at normal time in a conventional PON system having a redundant configuration.
Further, in the redundant transmission method using the dynamic SW unit, the switching process in the upper layer can eliminate the need for the ranging process in the PON layer in the switching process, so that the switching process can be speeded up.
In addition, according to the present invention, since switching control in units of ONUs is possible, even if a non-redundant ONU is accommodated in each PON system, communication disconnection due to switching of other ONUs having a redundant configuration is avoided. be able to.
In addition, since the present invention is made redundant at the wavelength level, even when the optical branching element and the ONU are configured by a non-redundant optical transmission line, a set of upstream signal wavelengths and downstream signal wavelengths in the ONU. If a wavelength demultiplexing unit capable of demultiplexing the wavelength of any one of the wavelength sets is installed, redundancy from the optical branching element to the PON termination unit of the OLT becomes possible. In other words, in the same PON system, it is possible to provide a mixture of non-redundant ONUs, optical branching elements to OLT PON termination units, and ONU to OLT PON termination units in different protection levels.

Embodiments of the present invention will be described with reference to the drawings.
The present invention provides a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission between a center side apparatus (OLT) and a subscriber side apparatus (ONU) through a plurality of optical transmission paths. It is.
(First embodiment)
Hereinafter, a redundant transmission system according to the first embodiment, in which different upstream and downstream wavelength sets are applied to each PON system, will be described.

FIG. 1 is a diagram illustrating a basic configuration of a redundant transmission system according to the first embodiment. The center side device (OLT) includes a pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, and a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength sets And an upper layer dynamic SW unit (OLT switching control means) for managing the current and spare connection information set for each wavelength set unit and controlling the switching between the current and spare connections, and the subscriber unit (ONU) Is a pair of ONUPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and for each wavelength set unit An upper layer dynamic SW unit (ONU switching control means) is provided for managing the set current and backup connection information and controlling switching between the current and backup connections.
The OLTPON termination unit and the ONUPON termination unit always communicate with each wavelength set unit, and the OLT-side dynamic SW unit and the ONU-side dynamic SW unit perform switching control between the active and standby connections set for each wavelength set unit. Then, the wavelength set to be communicated is selected in units of ONUs, and failure recovery is performed.

  The OLT and the ONU are connected by a plurality of optical transmission lines composed of an optical branching element (optical power splitter) of 2: 4n (n = 2 in FIG. 1) and an optical transmission line medium, as shown in FIG. Each PON system is assigned a wavelength set (λu1, λd1), (λu2, λd2), which is a set of the wavelength of the upstream signal and the wavelength of the downstream signal. Examples of the connection configuration of the optical branching element (optical power splitter) and the optical transmission line are shown in FIGS. FIG. 3 is a configuration example in which the OLT and the ONU are connected by a one-stage optical branching element, and FIG. 4 is a configuration example in which the OLT and the ONU are connected by a two-stage optical branching element. The number of branches and the number of stages of the optical branching element can be easily changed according to the service application. Assuming that the PON system that communicates via the PON termination unit # 1 of the OLT is the PON system # 1, and the PON system that communicates via the PON termination unit # 2 is the PON system # 2, the PON system # 1 includes (λu1, λd1 ), (Λu2, λd2) is assigned to the PON system # 2. The ONUs # 1 to #n (# 11 and # 12 in FIG. 1) normally belong to the PON system # 1 as shown in FIG. 2, and the wavelength set (λu1, λd1) is assigned to the working path and the wavelength set (λu2). , Λd2) as backup paths. Similarly, ONUs # n + 1 to # 2n (# 21 and # 22 in FIG. 1) normally belong to the PON system # 2 and use the wavelength set (λu2, λd2) as the working path. The wavelength set (λu1, λd1) operates as a backup path.

  The OLT optical wavelength demultiplexing unit # 1 for the PON system # 1 can perform wavelength demultiplexing of the wavelength set (λu1, λd1), and blocks the wavelengths of the wavelength set (λu2, λd2). Conversely, the OLT optical wavelength demultiplexing unit # 2 for the PON system # 2 can perform wavelength demultiplexing of the wavelength set (λu2, λd2), and blocks the wavelength set (λu1, λd1). In addition, the wavelength set (λu2, λd2) is blocked in the ONU, and the wavelength set (λu1, λd1) is blocked, and the wavelength set (λu1, λd1) is blocked. An optical wavelength demultiplexing unit # 2 that performs wavelength demultiplexing on only the wavelength set (λu2, λd2) is mounted. Thereby, in PON system # 1 (# 2), it can communicate without being influenced by the wavelength of the wavelength set of PON system # 2 (# 1).

  In the upper layer dynamic SW unit, a connection or a connection group is set in units of ONUs, and a communication destination ONU can be identified from the connection number. The working and backup connections are statically set as upper layer connections, and the dynamic SW unit manages the paired working and protection connection information and updates the connection information at the time of switching. In the PON system, the working path and the protection path are set through two wavelength sets (λu1, λd1) and (λu2, λd2), and the communication between the working path and the protection path is always established in the PON system. Therefore, during normal operation, the dynamic SW unit can send and receive client signals via the working connection, and can confirm connectivity and switch control information via CC (Continuous Check) via the spare connection. is there.

In FIG. 1, for example, when a failure occurs in the optical transmission line # 111, the dynamic SW unit of the ONU # 11 receives a reception signal abnormality signal at the path level from the ONUPON termination unit # 1, or reception at the connection level. Using the detection of signal abnormality as a trigger, the current connection via the optical transmission path # 111- # 1 is switched to the spare connection via the optical transmission path # 112- # 2 while performing switching control communication.
Note that the dynamic SW unit mounted on the OLT can also perform switching control triggered by detection of an abnormality in the received signal at the connection level.

Note that the switching methods described in Non-Patent Document 3 and Non-Patent Document 4 are representative and applicable as the connection switching method in the upper layer.
Further, when the operator needs to switch the system via the operation system, it can be realized by transmitting a command (system switching signal) from the operation system to the OLT and transmitting a command from the OLT to the ONU.

  FIG. 5 is an example in which a failure occurs in the section of ONU # 11 to the optical branching element and switching is performed in the configuration of FIG. The dynamic SW unit implemented in the OLT and ONU # 11 can receive the reception signal abnormality signal from the PON termination unit or detect the reception signal abnormality. Fault recovery is possible by switching from the path # 111- # 1 to the optical transmission path # 112- # 2.

  FIG. 6 shows a switching control flow of this embodiment. The dynamic SW unit installed facing the OLT and the ONU always confirms the connectivity by CC (Continuous Check) on the working and backup connections. When a failure occurs on the current connection, switching from the current connection to the spare connection is performed in the opposing dynamic SW unit. Note that switching control information of switching request = signal failure (SF: Signal Failure) and selection system = 1 system (working path) is transmitted to the opposing dynamic SW unit in the state before the completion of switching after failure detection. After the switching is completed, switching control information of switching request = signal failure (SF: Signal Failure) and selection system = 2 system (backup path) is transmitted. After the switching is completed, the switching information of the selection system received from the opposing dynamic SW unit is referred to and it is confirmed that no mismatch occurs in the selection system. In FIG. 6, switching request = XX (X is an arbitrary value) is, for example, normal (NR: No Request), signal interruption, signal quality degradation, forced switching (by operator), manual switching, etc. Is a message (switching control information) for transmitting a request for switching control with the highest priority to the opposite switching device, and the selection system = X system (X is an arbitrary value) is actually selected within the own device. This message (switching control information) indicates the active system (working path (system 0), backup path (system 1)).

  FIG. 7 is an example in which a failure occurs in the section of the optical branching element to the OLT and switching is performed in the configuration of FIG. Since the dynamic SW unit mounted on the OLT and the ONUs # 11 and # 12 can receive the reception signal abnormal signal from the PON termination unit or detect the reception signal abnormality as described above, the OLT to the ONU # 11 It is possible to recover from the failure by switching from the current connection to the spare connection in the section of OLT and ONU # 12. Note that the switching control flow of this embodiment is the same as that shown in FIG.

(Second Embodiment)
FIG. 8 is a diagram illustrating a basic configuration of a redundant transmission system according to the second embodiment. The configuration of the optical branching element and the optical transmission line, and the assignment of the wavelength set in the second embodiment are the same as those in the first embodiment. However, only one of the working path and the backup path can be established between the OLTPON termination unit and the ONUPON termination unit, and either connection is selectively established according to the failure status by switching control at the PON system level. There is a need. The ONT registration control unit of the OLT links the connection or connection group set in the ONU unit in the dynamic SW unit of the upper layer in conjunction with the switching control in the PON system. The OLTPON termination unit # 1 or the OLTPON termination unit # In order to switch to 2, it is necessary to transmit a switching request signal to the dynamic SW unit of the upper layer.

  In the second embodiment, the OLT includes a pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, and a pair of optical wavelength multiplexing for demultiplexing the wavelengths of the wavelength sets. A separation unit and an ONU registration control unit (OLT switching control means) for managing ONUs belonging to each OLTPON termination unit and switching control within the OLT are provided. The ONU includes a non-redundant ONUPON termination unit and a wavelength set of transmission and reception wavelengths. ONU registration switching for managing a pair of optical transmission / reception units having different wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength set, and an OLTPON termination unit to which the own ONU belongs and switching control within the ONU A control unit and a system switching electric SW unit (ONU switching control means) are provided.

  In the ONU, the ONU registration switching control unit receives the reception signal abnormality signal from the ONUPON termination unit. This received signal abnormality signal is detected by the ONUPON termination unit when the ONUPON termination unit detects a signal interruption of the received signal, transmission quality degradation (for example, bit error), or a monitoring control signal indicating an abnormal signal of the selected system. A signal to be transmitted. When this signal is received by the ONU registration switching control unit, a system switching control signal is transmitted to the system switching electrical SW unit, and the system switching electrical SW unit performs system switching and stops the optical output of the optical transmission / reception unit serving as the switching source. Then, the optical transmission / reception unit to be switched to starts optical output. In addition, after the above system switching and optical output control are completed, the ONU registration switching control unit transmits an ONU registration initialization signal to the ONUPON termination unit, transitions the ONU to an unregistered state, and performs ranging processing and registration from the OLT. Wait for processing.

  In the OLT, ranging processing and registration processing for the corresponding ONU are performed in the switching destination OLTPON termination unit, and registration deletion processing of the corresponding ONU is performed in the switching source OLTPON termination unit. Further, a switching request signal is transmitted to the dynamic SW unit in order to switch the connection of the corresponding ONU in the upper layer dynamic SW unit.

  On the other hand, on the OLT side, when the ONU registration control unit receives a reception signal abnormality signal from the OLTPON termination unit, it transmits a system switching signal to the corresponding ONU, transmits an ONU registration initialization signal to the OLTPON termination unit, and The corresponding ONU is transitioned to an unregistered state at the OLTPON termination unit, and ranging processing and registration processing are started at the switching destination OLTPON termination unit. Further, a switching request signal is transmitted to the dynamic SW unit in order to switch the connection of the corresponding ONU in the upper layer dynamic SW unit.

  If the operator needs to switch the system via the operation system, it can be realized by sending a command (system switch signal) from the operation system to the OLT and a command (system switch signal) from the OLT to the ONU. It is.

FIG. 9 is an example in which a failure occurs in the section of ONU # 11 to the optical branching element and switching is performed in the configuration of FIG.
FIG. 10 shows a switching control flow of this embodiment. ONU # 11 notifies the ONU registration switching control unit of the abnormality of the received signal in order to detect a failure at the ONUPON termination unit. The ONU registration switching control unit performs system switching of the system switching electrical SW unit, stops the optical output of the optical transmission / reception unit # 1 and starts the optical output of the optical transmission / reception unit # 2, and receives a control completion response from each functional unit , ONU registration initialization is performed for the ONUPON terminal.

  Next, the ONUPON terminator transmits a ranging request signal, which is a registration request, to the OLT in response to the Discovery signal received from the switching destination OLTPON terminator # 2. The OLTPON termination unit # 2 notifies the ONU registration control unit of reception of the ranging request signal. The ONU registration control unit transfers the ONU information from the PON termination unit # 1 to the PON termination unit # 2, and the PON termination unit # 2. In addition to performing the unregistering process of the ONU in 1, a switching request from the PON termination unit # 1 to the PON termination unit # 2 is transmitted to the upper dynamic SW unit via the PON termination unit # 2. The ONU registration control unit receives the completion response from the ONU information transfer, the ONU unregistered process, and the upper dynamic SW unit, and confirms the completion of the OLT switching process.

  Thereafter, a registration completion (Register) notification is transmitted from the ONT registration control unit of the OLT to the ONU via the PON terminal unit # 2. The ONUPON termination unit that has received the registration completion transmits a registration completion notification to the ONU registration switching control unit and also transmits a response (Ack) to the switching destination OLTPON termination unit # 2. If necessary, a continuity test for confirming the transmission quality of the optical transmission to be switched may be performed.

As described above, all the switching processes are completed, and the transmission of the main signal is resumed via the optical transmission line of the PON system # 2. Although not shown in FIG. 10, all signals in the uplink direction are transmitted according to the timing and band assigned from the OLT. In addition, this embodiment is merely an example, and it is needless to say that some processes can be omitted or the execution timing can be changed.
Further, whether or not the periodic connectivity check between the OLT and the ONU is performed depends on the implementation, and the above embodiment describes the case where the periodic connectivity check is not performed. In this case, the OLT side cannot determine whether data transmission / reception is disabled due to a failure in this section or whether there is no data to be transmitted from the ONU in a normal state. The occurrence cannot be detected, and the failure is detected on the ONU side.

  FIG. 11 is an example in which a failure occurs in the section of the optical branching element to the OLT and switching is performed in the configuration of FIG. In this case, since the failure can be detected due to a decrease in the optical input level or the like in both the OLT, ONU # 11, and ONU # 12, the OLT does not wait for the ranging processing request from the ONU and The switching control of the section from OLT to ONU # 12 can be started.

  FIG. 12 shows a switching control flow of this embodiment. The difference between this embodiment and FIG. 10 is only the timing of starting the switching process on the OLT side. In FIG. 10, the trigger for starting the switching process is reception of a registration request from the ONU. This is a notification of abnormality in the received signal from the OLTPON terminal.

(Third embodiment)
FIG. 13 shows a basic configuration of a redundant transmission system according to the third embodiment. The configuration of the optical branching element and the optical transmission line and the allocation of the wavelength set in the third embodiment are the same as those in the first embodiment and the second embodiment. As in the second embodiment, at the PON system level, only one of the working path and the backup path can be established between the OLTPON termination unit and the ONUPON termination unit, and either one is selectively established depending on the failure status. There is a need to.

  In the third embodiment, the OLT includes a pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, and a pair of optical wavelength multiplexing / demultiplexing for demultiplexing the wavelengths of the wavelength sets. And an ONU registration control unit (OLT switching control means) for managing ONUs belonging to each OLTPON termination unit and switching control within the OLT. The ONU includes a non-redundant ONUPON termination unit and a non-redundant wavelength tunable light. A transmission / reception unit, a pair of optical wavelength demultiplexing units for demultiplexing wavelengths of a wavelength set, an ONU registration switching control unit for performing management of the OLTPON termination unit to which the own ONU belongs and switching control within the ONU, and system switching light An SW unit (ONU switching control means) is provided.

When the ONU registration switching control unit receives a reception signal abnormality signal from the ONUPON termination unit, the ONU registration switching control unit transmits a system switching control signal to the system switching light SW unit, and the system switching light SW unit performs system switching, and a wavelength tunable optical transceiver unit Performs wavelength conversion of the transmission wavelength to the wavelength set of the switching destination OLTPON termination unit. The ONU registration switching control unit transmits an ONU registration initialization signal to the ONUPON termination unit after the above system switching and wavelength conversion is completed, transitions the ONU to an unregistered state, and ranging processing and registration processing from the OLT. Wait for. The subsequent switching control in the OLT is the same as that in the second embodiment.
On the other hand, on the OLT side, when the ONU registration control unit receives a reception signal abnormality signal from the OLTPON termination unit, the switching control in the OLT is the same as in the second embodiment.

FIG. 14 is an example in which a fault occurs in the section of ONU # 11 to the optical branching element and switching is performed in the configuration of FIG.
FIG. 15 shows a switching control flow of this embodiment. The difference from FIG. 10 is only the light output control in the ONU switching process. In this embodiment, since the wavelength tunable optical transceiver is used, the procedure for stopping the optical output of the switching source optical transceiver and starting the optical output of the switching destination optical transceiver is wavelength conversion in the wavelength tunable optical transceiver. Other processing is the same as the switching control flow of FIG.

FIG. 16 is an example in which a failure occurs in the section of the optical branching element to the OLT and switching is performed in the configuration of FIG.
FIG. 17 shows a switching control flow of this embodiment. In this case, since the failure can be detected due to a decrease in the optical input level or the like in both the OLT, ONU # 11, and ONU # 12, the OLT does not wait for the ranging processing request from the ONU, and the section between OLT and ONU # 11. The switching control of the section from OLT to ONU # 12 can be started. Therefore, the difference between this embodiment and FIG. 15 is only the timing of starting the switching process on the OLT side. In FIG. 15, the trigger for starting the switching process is reception of a registration request from the ONU. , It becomes a notification of an abnormality in the received signal from the OLTPON terminal.

  The redundant transmission systems shown in the first, second, and third embodiments are accommodated in the PON system at the time of failure recovery when both PON systems # 1 and # 2 are fully using the transmission band. Since the number of ONUs to be increased increases from n to 2n, there is a problem that the guaranteed bandwidth for each ONU is reduced to about 50% of the normal time. For this reason, in each PON system, it is necessary to set the accommodation rate of the high-priority class data traffic to be restored by switching to 50% of the transmission band.

  Next, a redundant transmission system in which an upstream wavelength is shared with respect to the PON systems # 1 and # 2 and a wavelength set in which only the downstream wavelength is different as shown in FIG. 18 will be described. Sharing the wavelength of the upstream signal is applicable when the upstream transmission band is smaller than the downstream direction and the transmission band is asymmetric. In this case, the control timings (such as IEEE Std802.3ah MPCP timing) in the OLPON termination units # 1 and # 2 of each PON system are synchronized, and the uplink bandwidth allocation slots in the PON systems # 1 and # 2 are fixed. Control such as setting at timing is required.

FIG. 19 is a diagram illustrating an ONU configuration example for the first embodiment (FIG. 1) when an upstream wavelength is shared. Although the configuration is the same as in FIG. 1, the wavelength in the upstream direction is the same, so the optical transceivers that are paired with the ONU are optical transceivers having the same transmission wavelength.
20 and 21 show examples of uplink band allocation slots for the first embodiment when uplink wavelengths are shared.
LLID (Logical Link IDentifier) in the figure is an identifier of a logical link. The reference numerals in the figure indicate the case where ONUs and LLIDs have a one-to-one correspondence.

  In the first embodiment, since the communication of both the working path and the backup path of each ONU is established, the working path of ONU # 1 to #n, ONU # n + 1 is included in the bandwidth allocation slot of PON system # 1. Bands for the backup paths # 1 to # 2n are allocated, and band allocation slots of the PON system # 2 are allocated bands for the backup paths of the ONUs # 1 to #n and the working paths of the ONUs # n + 1 to # 2n. Bandwidth allocation to ONUs in each slot is performed centrally and dynamically by the OLTPON termination unit according to the request of each ONUPON termination unit. Normally, as shown in FIG. 20, only the switching control information and the connectivity confirmation by the CC are performed on the protection path, so that the allocated bandwidth for the protection path is reduced. FIG. 21 shows a case where ONUs # 1 to #n are switched to the PON system # 2 due to a transmission quality deterioration (bit error) failure in the PON system # 1, and data communication is performed with all ONUs via the PON system # 2. is there. In this case, since the number of ONUs to be allocated by the PON system # 2 increases, the allocated bandwidth for each ONU becomes smaller than that at the normal time.

  In the first embodiment, even when the upstream wavelength (the same wavelength) is shared by both PON systems, as shown in FIGS. 20 and 21, the upstream bandwidth allocation slot is fixed to each PON system unit. Therefore, switching control is possible because the independence of the path can be ensured even in the active and backup connections in the dynamic SW unit.

FIG. 22 is a diagram illustrating an ONU configuration example for the second embodiment (FIG. 8) when the upstream wavelength is shared, and FIG. 23 is a third embodiment when the upstream wavelength is shared. It is a figure which shows the example of ONU structure with respect to (FIG. 13). FIG. 24 and FIG. 25 show examples of uplink band allocation slots for the second and third embodiments when the uplink wavelength is shared.
In the second and third embodiments, since communication of only the working path of each ONU is normally established, as shown in FIG. 24, the ONU is placed in the band allocation slot of the PON system # 1. Bands for the working paths # 1 to #n are allocated, and bands for the working paths of ONUs # n + 1 to # 2n are allocated to the band allocation slots of the PON system # 2. FIG. 25 shows a case where ONUs # 1 to #n are switched to the PON system # 2 due to a failure of the PON system # 1, and data communication is performed with all ONUs via the PON system # 2. Also in this case, as in the first embodiment, the number of ONUs to be allocated by the PON system # 2 increases, so that the allocated bandwidth for each ONU becomes smaller than in the normal case.

  In the second embodiment and the third embodiment, as shown in FIG. 24 and FIG. 25, even in the case where the upstream wavelength (same wavelength) is upstream shared by both PON systems, the upstream bandwidth allocation slot Is fixedly assigned to each PON system unit, so that the independence of the working path and the backup path in the PON system can be ensured, so that switching control is possible. In the case of the third embodiment, as a matter of course, since the same wavelength is used as the transmission wavelength from the ONU before switching and after switching, wavelength conversion processing in the wavelength tunable optical transceiver is not necessary.

  Each OLTPON terminator passes only data received from the upstream bandwidth allocation slot addressed to itself, and discards data received from upstream bandwidth allocation slots other than itself.

As described above, when the wavelength of the upstream signal is shared in each PON system, in the redundant transmission system according to the first embodiment and the second embodiment, the optical transmission / reception unit and the optical wavelength multiplexing / demultiplexing according to the wavelength set are used. The failure recovery can be realized by installing a section and selecting an upstream bandwidth allocation slot according to the PON system that communicates.
Further, in the redundant transmission system according to the third embodiment, an optical transmission / reception unit and an optical wavelength multiplexing / demultiplexing unit corresponding to the wavelength set are installed, and an uplink band allocation slot is selected according to the PON system that communicates. Failure recovery can be realized. However, since the wavelength tunable optical transmission / reception unit in the ONU can be replaced with an optical transmission / reception unit that outputs a fixed wavelength, an ONU configuration in which an optical transmission / reception unit of a fixed wavelength is mounted on the ONU as shown in FIG. Economical.

(Fourth embodiment)
The fourth embodiment is a configuration in which the optical transmission line in the section from the ONU to the optical branching element is not made redundant in the configurations of the first, second, and third embodiments.
Since the path is made redundant at the wavelength level by assigning different wavelengths to the working path and the backup path, the present invention can be applied even if the optical transmission path is non-redundant in some sections. FIG. 26 shows wavelength assignments for wavelength sets (λu1, λd1) and (λu2, λd2) in which the wavelength of the uplink signal and the wavelength of the downlink signal are different, and FIG. 27 shows wavelength sets (λu1, λd1), ( The wavelength assignment for λu1, λd2) is shown. In the present embodiment, since only the physical configuration is changed, there is no influence or change on the sequence flow of the switching process.

  Examples of the fiber connection configuration in the fourth embodiment are shown in FIGS. 28 shows an example of a fiber connection configuration when the optical branching element is configured in one stage, FIG. 29 is an example of a fiber connection configuration when the optical branching element is configured in two stages, and FIG. 30 shows an optical branching element configured in two stages. This is an example of a fiber connection configuration in the case where the optical transmission path between the first to second stage optical branching elements is also made redundant.

  A configuration example of the ONU in the fourth embodiment is shown in FIGS. 31 shows an ONU configuration example for the first embodiment (FIG. 1), FIG. 32 shows an ONU configuration example for the second embodiment (FIG. 8), and FIG. 33 shows an ONU configuration example for the third embodiment (FIG. 13). It is. As shown in each configuration example, the fourth embodiment can be achieved by simply replacing the optical wavelength demultiplexing unit in the ONU with a pair of optical wavelength demultiplexing units for the two-core fiber from an optical wavelength demultiplexing unit for the one-core fiber. Redundancy is also possible.

Even when the upstream wavelength (the same wavelength) is shared by both PON systems, the upstream path allocation slot is fixedly assigned to each PON system unit, so that the working path and the backup path in the PON system are allocated. Independence of the route can be secured.
Examples of the configuration of the ONU when sharing the upstream wavelength are shown in FIGS. FIG. 34 shows an ONU configuration example for the first embodiment (FIG. 1), FIG. 35 shows an ONU configuration example for the second embodiment (FIG. 8), and FIG. 36 shows an ONU configuration example for the third embodiment (FIG. 13). It is.

(Fifth embodiment)
In the fifth embodiment, ONUs having three different protection levels of non-redundant ONUs, optical branching elements to OLTPON termination units, and ONU to OLTPON termination units are mixed. FIG. 37 is a fiber connection configuration example in which the optical branching element is configured in one stage, and FIG. 38 is a fiber connection configuration example in which the optical branching element is configured in two stages. In the present embodiment, since only the physical configuration is changed, there is no influence or change on the sequence flow of the switching process.

  In FIG. 37, ONU # 11 and ONU # 23 are non-redundant ONUs, ONU # 12 and ONU # 22 are ONUs that make the optical transmission path from the OLTPON termination unit to the optical branching element redundant, and ONU # 13 and ONU # 21 is an ONU that makes the optical transmission path from the OLTPON terminal to the ONU redundant. Since ONUs # 11 and # 23 are non-redundant ONUs belonging to the PON system # 1, an optical wavelength demultiplexing unit for blocking the wavelength of the PON system # 2 is required. Also, in the PON systems # 1 and # 2, when wavelength sets having different wavelength sets for upstream and downstream signals are assigned, the ONU configurations of FIGS. 31 to 33 can be applied to the ONUs # 12 and # 22. Yes, the ONU configurations of FIGS. 1, 8, and 13 can be applied to the ONUs # 13 and # 21. However, since all ONUs need to be arranged by selecting an ONU configuration according to the OLT configuration, for example, it is not possible to arrange ONUs having different control methods as shown in FIG. 1 and FIG. . Also, as described above, ONU # 12, # 22 and ONU # 13, # 21 differ only in the optical wavelength multiplexing / demultiplexing section, and therefore provide different protection levels for each ONU by the same switching control method. Is possible.

In FIG. 38, ONU # 11 and ONU # 12 are non-redundant ONUs, ONU # 13 and ONU # 14 are ONUs that make the optical transmission path from the OLTPON termination unit to the optical branching element redundant, and ONU # 15 and ONU # This is an example of a configuration in which 16 is an ONU that provides redundancy from the optical transmission terminal to the ONU. The optical branching element is composed of two stages, and it is possible to recover from a failure in the event of an optical transmission line failure between the first and second stage optical branching elements. However, in this configuration example, in order to prevent collision due to wavelength, the second-stage optical branching element is divided into two types, and ONUs # 13 and # 14 in which the optical transmission path between the optical branching element and the ONU is non-redundant. Therefore, the optical branching device for ONUs # 15 and # 16 in which the optical transmission line in the same section becomes redundant must be distinguished from each other. The non-redundant ONU can be accommodated in any optical branching element. In FIG. 38, the former optical branching element is described as # 1, and the latter optical branching element is described as # 2, and the optical transmission path between the optical branching element # 1 and the first stage optical branching element is redundant. The optical branching element # 2 is connected so that the optical transmission path in the same section is non-redundant and the optical transmission path between the optical branching element # 2 and the ONU is redundant. In FIG. 38, ONUs # 11, # 13, and # 14 are accommodated in the optical branching element # 1, and ONUs # 12, # 15, and # 16 are accommodated in the optical branching element # 2.
Therefore, in the fifth embodiment, different protection levels can be simultaneously provided to the ONU according to the fiber connection configuration.

It is a figure which shows the basic composition of the redundant transmission system in connection with 1st Embodiment. It is a figure which shows the structure of the wavelength path in case of uplink wavelength non-sharing. It is a figure which shows the example of a connection structure of an optical transmission line. It is a figure which shows the example of a connection structure of an optical transmission line. It is a figure which shows the example which a failure generate | occur | produces in the area of ONU # 11-optical branching element, and switches. It is a figure which shows the switching control flow of 1st Embodiment. It is a figure which shows the example which a failure generate | occur | produces in the area of optical branching element-OLT, and switches. It is a figure which shows the basic composition of the redundant transmission system in connection with 2nd Embodiment. It is a figure which shows the example which a failure generate | occur | produces in the area of ONU # 11-optical branching element, and switches. It is a figure which shows the switching control flow when a failure generate | occur | produces in the area of ONU # 11-optical branching element. It is a figure which shows the example which a failure generate | occur | produces in the area of optical branching element-OLT, and switches. It is a figure which shows the switching control flow when a failure generate | occur | produces in the area of an optical branching element-OLT. It is a figure which shows the basic composition of the redundant transmission system in connection with 3rd Embodiment. It is a figure which shows the example which a failure generate | occur | produces in the area of ONU # 11-optical branching element, and switches. It is a figure which shows the switching control flow when a failure generate | occur | produces in the area of ONU # 11-optical branching element. It is a figure which shows the example which a failure generate | occur | produces in the area of optical branching element-OLT, and switches. It is a figure which shows the switching control flow when a failure generate | occur | produces in the area of an optical branching element-OLT. It is a figure which shows the structure of the wavelength path in the case of uplink wavelength sharing. It is a figure which shows the example of ONU structure with respect to 1st Embodiment in the case of uplink wavelength sharing. It is a figure which shows the example of the band allocation slot of the uplink direction with respect to 1st Embodiment in the normal time in case of uplink wavelength sharing. It is a figure which shows the example of the band allocation slot of the up direction with respect to 1st Embodiment at the time of the failure in the case of uplink wavelength sharing. It is a figure which shows the example of ONU structure with respect to 2nd Embodiment in the case of uplink wavelength sharing. It is a figure which shows the example of ONU structure with respect to 3rd Embodiment in the case of uplink wavelength sharing. It is a figure which shows the example of the band allocation slot of the uplink direction with respect to 2nd Embodiment and 3rd Embodiment in the normal time in case of uplink wavelength sharing. It is a figure which shows the example of the band allocation slot of the uplink direction with respect to 2nd Embodiment and 3rd Embodiment at the time of the failure in the case of uplink wavelength sharing. It is a figure which shows the structure of the wavelength path in the case of uplink wavelength non-sharing in 4th Embodiment. It is a figure which shows the structure of the wavelength path in the case of uplink wavelength sharing in 4th Embodiment. It is a figure which shows the example of a connection structure of the optical transmission path in 4th Embodiment. It is a figure which shows the example of a connection structure of the optical transmission path in 4th Embodiment. It is a figure which shows the example of a connection structure of the optical transmission path in 4th Embodiment. It is a figure which shows the structural example of ONU in 4th Embodiment. It is a figure which shows the structural example of ONU in 4th Embodiment. It is a figure which shows the structural example of ONU in 4th Embodiment. It is a figure which shows the structural example of ONU in the case of uplink wavelength sharing. It is a figure which shows the structural example of ONU in the case of uplink wavelength sharing. It is a figure which shows the structural example of ONU in the case of uplink wavelength sharing. It is a figure which shows the connection structural example of the optical transmission path in 5th Embodiment. It is a figure which shows the connection structural example of the optical transmission path in 5th Embodiment. It is a figure which shows the structural example of the PON system provided with the conventional redundant function. It is a figure which shows the structural example of the PON system provided with the conventional redundant function. It is a figure which shows the structural example of the PON system provided with the conventional redundant function.

Claims (16)

A center side device (OLT) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of subscriber side devices (ONUs), and the OLT via the plurality of optical transmission lines In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission with an ONU,
The OLT is for demultiplexing the communication wavelength of each optical transmitter / receiver, a pair of OLTPON termination units, a pair of optical transmitter / receiver units having different wavelength sets, which is a set of wavelengths of upstream and downstream signals A pair of optical wavelength demultiplexing units and an OLT switching control means for performing switching control of the transmission line system;
The ONU includes a pair of optical wavelength demultiplexing units that demultiplex the wavelengths of the wavelength set, an optical transceiver that can communicate using the wavelengths of the wavelength set, an ONUPON termination unit, and transmission path system switching control. ONU switching control means for performing
A redundant transmission system in a PON system, wherein a wavelength set to be communicated is selected for each ONU unit between the OLT and the ONU, and a transmission path system is switched. A center side device (OLT) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of subscriber side devices (ONUs), and the OLT via the plurality of optical transmission lines In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission with an ONU,
The OLT includes a pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing wavelengths of the wavelength sets, and each wavelength It includes a dynamic SW unit of an upper layer that performs management of current and backup connection information set in units of units and switching control between current and backup connections,
The ONU includes a pair of ONUPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing wavelengths of the wavelength sets, and each wavelength It includes a dynamic SW unit of an upper layer that performs management of current and backup connection information set in units of units and switching control between current and backup connections,
The OLTPON termination unit and the ONUPON termination unit always communicate with each wavelength set unit, and the OLT-side dynamic SW unit and the ONU-side dynamic SW unit switch and control the working and backup connections set for each wavelength set unit. Accordingly, a redundant transmission system in a PON system is characterized in that a wavelength set to be communicated is selected in units of ONUs, and failure recovery is performed. A center side device (OLT) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of subscriber side devices (ONUs), and the OLT via the plurality of optical transmission lines In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission with an ONU,
The OLT includes a pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and each OLTPON An ONU registration control unit that performs management of ONUs belonging to the terminal unit and system switching control within the OLT is provided.
The ONU includes a non-redundant ONUPON termination unit, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing wavelengths of the wavelength sets, and an own ONU Comprising an ONU registration switching control unit and a system switching electrical SW unit that perform management of the OLPON termination unit to which the system belongs and system switching control within the ONU,
The OLTPON terminator and the ONUPON terminator communicate with each other through the wavelength of any wavelength set unit,
When the ONU registration switching control unit of the ONU receives the reception signal abnormality signal, the switching of the system switching electrical SW unit, the start of optical output of the transmission wavelength of the ONU side optical transmission / reception unit of the switching destination, and the switching source Stop the optical output of the transmission wavelength of the ONU side optical transceiver and perform registration control for the switching destination OLPON termination unit,
The ONT registration control unit of the OLT receives a signal notifying that the reception signal abnormality signal or the registration request from the ONU has been received from the OLTPON termination unit. A redundant transmission system in a PON system, wherein registration deletion control and registration control in an OLTPON termination unit of a switching destination are performed to select a wavelength set for communication in units of ONUs and perform fault recovery.   4. The redundant transmission system in the PON system according to claim 1, wherein the wavelength sets have the same upstream signal wavelength and different downstream signal wavelengths. 5. A center side device (OLT) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of subscriber side devices (ONUs), and the OLT via the plurality of optical transmission lines In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission with an ONU,
The OLT includes a pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and each OLTPON An ONU registration control unit that performs management of ONUs belonging to the terminal unit and system switching control within the OLT is provided.
The ONU includes a non-redundant ONUPON termination unit, a non-redundant wavelength tunable optical transmission / reception unit, a pair of optical wavelength demultiplexing units for demultiplexing wavelengths of the wavelength set, and an OLTPON termination unit to which the own ONU belongs. An ONU registration switching control unit and a system switching light SW unit for managing the system and controlling the system switching in the ONU,
The OLTPON terminator and the ONUPON terminator communicate with each other through the wavelength of any wavelength set unit,
When the ONU registration switching control unit of the ONU receives the reception signal abnormality signal, the wavelength conversion of the transmission wavelength corresponding to the wavelength set of the switching destination OLTPON termination unit in the wavelength tunable optical transmission / reception unit, and the system switching light Perform switching control of SW part and registration control for OLPON terminal part of switching destination,
The ONT registration control unit of the OLT receives a signal notifying that the reception signal abnormality signal or the registration request from the ONU has been received from the OLTPON termination unit. A redundant transmission system in a PON system, wherein registration deletion control and registration control in an OLTPON termination unit of a switching destination are performed to select a wavelength set for communication in units of ONUs and perform fault recovery. A center side device (OLT) connected to a plurality of optical transmission lines composed of an optical branching element and an optical transmission line medium, and a plurality of subscriber side devices (ONUs), and the OLT via the plurality of optical transmission lines In a redundant transmission system in a point-multipoint optical transmission system (PON system) that performs signal transmission with an ONU,
The OLT is a pair of OLTPON termination units, a pair of optical transmission / reception units having the same upstream signal wavelength and different downstream signal wavelengths, and a pair for demultiplexing the communication wavelength of each optical transceiver. And an ONU registration control unit that performs management of ONUs belonging to each OLTPON termination unit and system switching control in the OLT,
The ONU includes a non-redundant ONUPON termination unit, a non-redundant optical transmission / reception unit that differs only in reception wavelength, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the communication wavelength of the optical transceiver, An ONU registration switching control unit and a system switching optical SW unit that perform management of an OLTPON termination unit and system switching control in the ONU,
The OLTPON terminator and the ONUPON terminator communicate with each other through the wavelength of any wavelength set unit,
When the ONU registration switching control unit of the ONU receives a reception signal abnormality signal, the ONU registration switching control unit performs switching control of the system switching optical SW unit and registration control for the switching destination OLPON termination unit,
The ONT registration control unit of the OLT receives a signal notifying that the received signal abnormality signal or the registration request from the ONU has been received from the OLTPON termination unit, so that the registration at the switching source OLTPON termination unit for the corresponding ONU A redundant transmission system in a PON system, wherein deletion control and registration control at a switching destination OLTPON termination unit are performed to select a wavelength set for communication in units of ONUs and perform failure recovery. In a center side device (OLT) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a plurality of subscriber side devices (ONUs) via a plurality of optical transmission paths,
A pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and set for each wavelength set A higher layer dynamic SW unit for managing the current and spare connection information and controlling the switching between the current and spare connections,
The OLTPON termination unit communicates with the ONU in units of wavelength sets, and the dynamic SW unit switches between active and standby connections set for each wavelength set unit, thereby selecting a wavelength set for communication in units of ONUs. PON system OLT characterized by switching transmission line systems. In a center side device (OLT) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a plurality of subscriber side devices (ONUs) via a plurality of optical transmission paths,
A pair of OLTPON termination units, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing wavelengths of the wavelength sets, and each OLTPON termination unit An ONU registration control unit that performs ONU management and system switching control within the OLT is provided.
When the ONU registration control unit receives from the OLTPON termination unit a signal indicating that the received signal abnormality signal or the registration request from the ONU has been received, the registration deletion at the switching source OLTPON termination unit for the corresponding ONU An OLT for a PON system, which performs control and registration control at the switching destination OLPON termination unit, selects a wavelength set for communication in units of ONUs, and switches a transmission path system.   9. The OLT of a PON system according to claim 7, wherein the wavelength set has the same upstream signal wavelength, and only the downstream signal wavelength is different. In a subscriber side device (ONU) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a center side device (OLT) via a plurality of optical transmission paths,
A pair of ONUPON termination units, a pair of optical transmission / reception units having different wavelength sets for transmission / reception wavelengths, a pair of optical wavelength demultiplexing units for demultiplexing the wavelengths of the wavelength sets, and set for each wavelength set A higher layer dynamic SW unit for managing the current and spare connection information and controlling the switching between the current and spare connections,
The ONUPON termination unit communicates with the OLT in units of wavelength sets, and the dynamic SW unit switches between active and standby connections set for each wavelength set unit, thereby selecting a wavelength set for communication in units of ONUs. The ONU of the PON system is characterized by switching the transmission path system. In a subscriber side device (ONU) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a center side device (OLT) via a plurality of optical transmission paths,
Non-redundant ONUPON termination unit, a pair of optical transmission / reception units having different wavelength sets of transmission / reception wavelengths, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing wavelengths of the wavelength set, and an OLTPON termination to which the own ONU belongs Comprising an ONU registration switching control unit and a system switching electric SW unit for managing the system and controlling the system switching in the ONU,
When the ONU registration switching control unit receives the reception signal abnormality signal, the switching of the system switching electrical SW unit, the start of optical output of the transmission wavelength of the switching destination optical transmission / reception unit, and the switching source optical transmission / reception unit An ONU of a PON system, wherein a transmission wavelength system is switched by selecting a wavelength set to be communicated in units of ONUs by stopping optical output of a transmission wavelength and performing registration control for a switching destination OLTPON termination unit.   12. The ONU of the PON system according to claim 10, wherein the wavelength sets have the same upstream signal wavelength and different downstream signal wavelengths. In a subscriber side device (ONU) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a center side device (OLT) via a plurality of optical transmission paths,
Non-redundant ONUPON termination unit, non-redundant wavelength tunable optical transmission / reception unit, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing wavelengths of the wavelength set, and management and ONU of the OLTPON termination unit to which the own ONU belongs An ONU registration switching control unit and a system switching light SW unit that perform system switching control in the system,
When the ONU registration switching control unit receives the reception signal abnormality signal, the wavelength conversion of the transmission wavelength corresponding to the wavelength set of the OLTPON termination unit of the switching destination in the wavelength tunable optical transmission / reception unit, and the system switching light SW unit The ONU of the PON system is characterized in that the wavelength set to be communicated is selected in units of ONUs and the transmission path system is switched by performing registration control on the switching destination OLTPON termination unit. In a subscriber side device (ONU) of a point-multipoint optical transmission system (PON system) that performs signal transmission with a center side device (OLT) via a plurality of optical transmission paths,
Non-redundant ONUPON termination unit, non-redundant optical transmission / reception unit that differs only in reception wavelength, a pair of optical wavelength multiplexing / demultiplexing units for demultiplexing the communication wavelength of the optical transceiver, and an OLPON termination unit to which the own ONU belongs An ONU registration switching control unit and a system switching light SW unit for managing the system and controlling the system switching in the ONU,
When the ONU registration switching control unit receives the reception signal abnormality signal, the switching of the system switching optical SW unit and the registration control for the switching destination OLTPON termination unit are performed, so that the wavelength set to be communicated is set on an ONU basis. An ONU of the PON system, characterized by selecting and switching the transmission path system. In a redundant transmission method in a point-multipoint optical transmission system (PON system) that performs signal transmission with a subscriber unit (ONU) via a plurality of optical transmission paths,
Between the OLT and the ONU, the working path accommodated in the working transmission line system and the protection path accommodated in the backup transmission line system are set using wavelength sets having different transmission and reception wavelengths, and each ONU at the time of failure is set. A redundant transmission method in a PON system, wherein a working path or a backup path is selected and switching between a working path and a backup transmission line system is performed.   16. The redundant transmission method in the PON system according to claim 15, wherein the wavelength sets have the same upstream signal wavelength and different downstream signal wavelengths.

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