JP2007124422A - Optical ring network apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable and new optical ring network apparatus having a large degree of freedom in network configuration. <P>SOLUTION: An in-use route is constituted by connecting nodes from a center node to Nn among n optical switch nodes N1, N2, ..., Nn which respectively include an in-use route optical switch circuit and a standby route optical switch circuit, in this order through the use of one optical fiber. A standby route is constituted by connecting nodes from the center node to N1 among n optical switch nodes Nn, ..., N2, N1, in this order through the use of one optical fiber. One optical ring network is constituted as a whole with the use of both the in-use route and the standby route. Communication is kept between the center node and whole optical terminating devices by changing over the route of an optical signal from the in-use route to the standby route concerning the optical switch node, which first detects the fault of the optical signal in one place on the in-use route, and the whole subsequent optical switch nodes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical ring network device. More specifically, the conventional passive optical network (PON), particularly the Gigabit Ethernet PON (GE-PON) that performs broadband packet transmission, is solved, and the transmission path in the optical network is improved. Even if a communication failure occurs due to an optical fiber disconnection accident or failure of an optical node device constituting the optical network, it can be recovered, a flexible network configuration is possible, and the network configuration and optical node device configuration are simple and cost-saving The present invention relates to an optical ring network device using an optical switch having any of the features that can be achieved.

  In recent years, the number of end users on the Internet, including general home users, has increased rapidly as services for providing end users with all kinds of information including voice, images, and videos using the Internet have spread. In order to smoothly provide such an Internet service to all end users, a so-called broadband communication network (broadband network) capable of delivering a large amount of information provided by a service provider (service provider) to the end users at high speed. In particular, in a subscriber network (access network) in which end users are directly accommodated, a broadband and low-cost packet data transmission network is required.

  As a typical access network aiming to meet such a demand, the Gigabit Ethernet PON (IEEE 802.3ah) defined by the Institute of Electrical and Electronics Engineering (IEEE) standard (IEEE 802.3ah) There is Gigabit Ethernet Passive Optical Network (GE-PON) (see Non-Patent Document 1).

  As shown in FIG. 2, the GE-PON includes a station side optical terminal device (OLT) 201 placed on the center node 200 and a plurality of subscriber side optical terminal devices (on the end user (subscriber) side). This is an optical network in a form in which optical network units (ONU) 202 are connected in a tree shape with optical fibers, and is indicated by a portion surrounded by a broken line 203 in FIG. One optical fiber 204 connected to the OLT 201 is connected and branched to a plurality of optical fibers 206 by a splitter 205 installed at an intermediate point between the OLT 201 and the ONU 202, and each branched optical fiber 206 is terminated by the ONU 202. The The OLT 201 is connected to a network service such as the Internet 208 through the upper network 207, and each user terminal 209 (for example, a personal computer: PC) connected to each ONU 202 is connected to the Internet or the like through the GE-PON 203. Connected to other services.

  In the GE-PON, the OLT 201 and the splitter 205, and the splitter 205 and each ONU 202 are connected by one optical fiber, respectively, so that the direction from the OLT 201 (or the center node 200) toward each ONU 202 (downward direction) ) And optical signals having different wavelengths in the upstream and downstream directions are used in order to avoid a collision between the ONU and the communication in the direction (upward direction) from each ONU to the OLT 201 (or the center node 200). Further, in GE-PON, by avoiding collision between upstream burst optical signals from a plurality of ONUs by a multi-point control protocol (Multi-Point Control Protocol: MPCP), point-to-point communication between the OLT and each ONU is performed. Emulation service is realized. In GE-PON, a burst optical signal having a Gigabit Ethernet packet frame is used, and bidirectional data communication at a maximum communication speed of 1 Gbps is possible.

  As described above, GE-PON is an optical fiber network, so it is inherently broadband, and multiple end users share OLT 201, splitter 205, and optical fiber 204 (feeder section) between OLT 201 and splitter 205. Therefore, it can be configured as an economical optical access network. In addition, because it uses a frame structure of Gigabit Ethernet, it can be easily matched with a higher-level IP network. Furthermore, existing components for Gigabit Ethernet that are widely used in LANs, etc. should be used for OLT and ONU electronic circuits. And the cost of the apparatus can be reduced.

  On the other hand, since the OLT 201 and each ONU 202 are connected to the GE-PON only by the optical fiber and the splitter 205 which is a passive element, the branch loss of the optical signal increases as the number of ONUs connected to the splitter increases. The first problem is that the optical signal is attenuated and the distance between the OLT and the ONU cannot be made sufficiently large (conversely, in order to enable a long transmission distance, the number of ONUs accommodated in one OLT) Need to reduce the cost).

  The second problem of GE-PON is security. That is, in the GE-PON, because of the network structure shown in FIG. 2, the downstream optical signal from the OLT toward a specific end user ONU is simultaneously delivered to all other end users ONU. For this reason, there is a possibility that the communication contents to the specific end user may be wiretapped or intercepted by other end users due to intention or accident of other end users. In order to avoid this risk, PON generally encrypts downstream signals, but encryption always involves the risk of being decrypted and increases the cost of the apparatus.

  A third problem of GE-PON is that communication from one ONU to another ONU or the entire GE-PON can be hindered. In other words, each ONU can usually send an upstream optical signal over the optical fiber only at the time and time length specified by the OLT by the MPCP. If an upstream optical signal is sent over an optical fiber at an unacceptable time or length of time, it may collide with upstream signals from other ONUs and hinder the communication. If this optical signal is sent out continuously, there is a possibility that communication of the entire GE-PON may be hindered. In addition, even if an optical signal is transmitted at a time other than the predetermined time and time due to a failure of the ONU optical transmitter, it may become a noise signal on the optical fiber and adversely affect the communication of the entire system. is there.

  In GE-PON, as shown in FIG. 2, since one ON-fiber 204 (feeder section) connecting the OLT 201 and the splitter 205 is used in common by all ONUs accommodated in this GE-PON, When a failure such as a cut occurs in the fiber, there is a problem in reliability that all communication in the GE-PON is cut off. This is the fourth problem of GE-PON.

  Since GE-PON is a tree (or star) optical network as shown in Fig. 2, it is relatively small (up to 16-32) within a relatively narrow service area (within 10-20km from the center node). When end users are scattered, it is most suitable as a broadband optical access network that economically realizes so-called Fiber To The Home (FTTH). However, the physical shape of the network is fixed in a tree shape, so that a relatively large number of end users are scattered within the service area, the service area itself is large, or the end users are, for example, along railways or roads. In the case where the GE-PON system is distributed over a relatively long distance, it is necessary to increase the number of GE-PON systems, or the total installation length of the optical fiber becomes large, which is not always economical. Thus, the application of GE-PON is optimal for a relatively small scale access network, and the fifth problem of GE-PON is that the degree of freedom with respect to the use and physical shape (topology) of the network is small. It is.

  Of the problems of GE-PON described above, the first, second, and third problems have been improved by the invention of the prior application “Optical Access Network Method and Optical Access Network” described in Patent Document 1. In addition, in the present specification, the invention of the prior application is referred to as “prior application 1” for the sake of convenience). FIGS. 3A and 3B show a configuration example of an optical access network according to the prior application 1. FIG. The optical access network of the prior application 1 shown in FIGS. 3A and 3B includes one center device 301 (corresponding to the OLT 201 in FIG. 2) and a plurality of remote devices 302 (corresponding to the ONU 202 in FIG. 2) (see FIG. 3). 3 (a) 303) or a plurality of optical switches (311 and a plurality of 310 in FIG. 3 (b)) to form a tree, and these optical switches (303 in FIG. 3 (a) or FIG. 3). (B) 311 and a plurality of 310) cause the downlink signal transmitted from the center device 301 to the remote device 302 to reach one remote device determined by the center device 301 based on the downlink signal information, and then An upstream signal transmitted to the center device 301 by one remote device determined by the center device 301 based on the signal information is made to reach the center device 301. In the configuration of FIG. 3B, the portion of the switch 303 in FIG. 3A is divided into two stages, and one light is provided between the first-stage switch 311 and the plurality of second-stage switches 310. Since the tree-like network 312 is connected by a fiber, a larger number of remote devices 302 can be connected as compared with the configuration of FIG.

  According to the prior application 1, an optical switch (303 in FIG. 3A or 311 and a plurality of 310 in FIG. 3B) is used in place of the GE-PON splitter 205 in FIG. The downstream optical signal is switched on a packet basis based on downstream signal information and delivered only to the target remote unit (ONU), and the upstream optical signal is switched on a packet basis based on downstream signal information to the center device (OLT). Therefore, the power loss of the optical signal can be made much smaller than that of the GE-PON in which the power of the optical signal must be branched by the number of remote devices by the splitter. The first problem can be solved practically.

  Further, according to the prior application 1, an optical switch (303 in FIG. 3A or 311 and a plurality of 310 in FIG. 3B) is used instead of the GE-PON splitter 205 in FIG. Since the downstream optical signal is switched in packet units based on the downstream signal information and delivered only to the target remote device, the downstream optical packet signal sent from the center device to the specific remote device is sent to the specific remote device by the optical switch. Only sent to other remote devices. Therefore, the second problem of GE-PON relating to the security of downstream optical signals can be solved.

  According to the prior application 1, instead of the GE-PON splitter 205 in FIG. 1, as shown in FIG. 3, an optical switch (303 in FIG. 3A or 311 in FIG. The optical switch is switched on a packet-by-packet basis based on downstream signal information so that only one remote device determined by the center device 301 reaches the center device 301 with an upstream signal transmitted to the center device 301. Therefore, even if another remote device sends an optical signal over an optical fiber to which the remote device is connected at an unacceptable time / length due to intentional or failure, the optical signal is not transmitted. It is blocked by a switch (303 in FIG. 3 (a), or 311 and a plurality of 310 in FIG. 3 (b)), and is fed to an optical fiber feeder section (304 in FIG. 3 (a), or FIG. 3). It will not be delivered to 304 and a plurality of 313) of b). Therefore, the third problem of the GE-PON related to the upstream optical signal can be solved.

  As described above, according to the prior application 1, the first, second, and third problems of GE-PON can be solved, but the fourth and fifth problems are not solved. In view of this, the first, second, and third problems of GE-PON and the fourth problem related to the reliability of the feeder section were solved in the prior application invention described in Patent Document 2. An optical switch device and an optical access network method using the same ”(this invention of the prior application is referred to as“ prior application 2 ”for the sake of convenience in this specification). FIG. 4 (a) and FIG. 2 shows an example of the configuration of an optical access network. The optical access network of the prior application 2 shown in FIGS. 4A and 4B includes a center device 401 and a plurality of remote devices 402, similar to the optical access network of the prior application 1 shown in FIGS. The optical switch shown in FIG. 3A is configured in a tree shape by using one (403 in FIG. 4A) or a plurality of optical switches (two 411 and 410 in FIG. 4B). While the number of terminals 303 on the center device side of 303 is one, the optical switch 403 in FIG. 4A has two terminals on the center device 401 side, and each terminal has a working optical fiber 404 in the feeder section and A spare optical fiber 405 in the feeder section is connected. The center device 401 has a working network interface 406 and a backup network interface 407, which are connected to the working optical fiber 404 in the feeder section and the standby optical fiber 405 in the feeder section, respectively. In the configuration example of FIG. 4B, one of the two optical switches 411 at the first stage is connected to the working optical fiber 404 as a working optical switch, and the other is connected to the working optical fiber 405 as a standby optical switch. The 4B has a plurality of terminals on the side of the first-stage optical switch, and the first-stage optical switch and the second-stage optical switch are connected to the respective terminals. 3 is connected to the active optical fiber 413 in the feeder section connecting the two and the spare optical fiber 414 in the feeder section connecting the first-stage optical switch and the second-stage optical switch. 312 is duplicated including an optical switch. With such a configuration, the optical communication path in the feeder section is duplexed (including the optical switch in the case of FIG. 4B), so that even if a failure occurs in the optical communication path in the current feeder section, a spare is provided. Communication can be maintained by switching to an optical communication path in the feeder section, and in addition to solving the first, second, and third problems of GE-PON, the fourth problem can also be solved.

    However, the optical access network of the prior application 2 is basically the same as the prior application 1 in that the network configuration in which the center device 401 and the plurality of remote devices 402 are configured in a tree shape using one or a plurality of optical switches. Therefore, even the optical access network of the prior application 2 cannot solve the fifth problem of GE-PON that the total fiber laying length increases depending on the case where the degree of freedom for the network application and topology is small.

   On the other hand, an optical ring network is known as an optical network that has a wide degree of freedom with respect to the use and topology of the network and is excellent in reliability. As a typical example of an optical ring network, there is a Universal Path Switched Ring (UPSR) used in a synchronous optical network (SONET) in North America, for example, as a medium / broadband optical transmission line (metro ring) in a city. Widely used for commercial purposes. UPSR is standardized by Non-Patent Document 2, and as shown in FIG. 5, a plurality of ring nodes (four in the example of FIG. 5, 500, 501, 502, and 503) are respectively ringed by two optical fibers 510 and 511. The transmission direction of the optical signal on the optical fiber 510 and the transmission direction of the optical signal on the optical fiber 511 are set to be opposite to each other. Sending signals from all ring nodes are always sent simultaneously on these two optical fibers, and the destination ring node always compares the optical signals received from these two optical fibers and receives the one judged to be normal. As a signal, it is transmitted to a lower-level device connected to the ring node. For example, when communication is performed between ring nodes 501 and 503 in FIG. 5, during normal operation of the ring, node 503 normally outputs a signal flowing from a node 501 on a route indicated by a solid line 513 on optical fiber 510. Although received as a signal, for example, when a failure such as an optical fiber cut occurs at a point 512 on the ring, the optical signal from the route of the solid line 513 is cut off, so that the node 503 indicates the optical fiber 511 on the broken line 514. The signal flowing through the route is judged as a normal signal and received. With this UPSR mechanism, a highly reliable optical ring network can be constructed, and the location where the ring node is installed is determined flexibly according to geographical conditions and service requirements. By connecting these, a highly flexible communication network is realized.

  However, since SONET UPSR is a SONET system that is a transmission layer based on the time division synchronous multiplexing method, protocol conversion is separately required in each ring node to accommodate Ethernet signals suitable for packet-based data communication. Therefore, there is a problem that the efficiency is remarkably deteriorated and the node device becomes complicated and expensive. For this reason, unlike the optical access networks of the prior applications 1 and 2 based on the Gigabit Ethernet frame, it is not suitable for an optical network for transmitting high-speed optical data packets directly to end users.

  On the other hand, an optical packet transfer ring network that branches and inserts high-speed optical data packets directly on the optical ring has also been proposed (see Patent Document 3). In the ring network disclosed in Patent Document 3, if the optical packet arriving through the optical fiber transmission line is not a packet addressed to the self-optical add / drop multiplexer / demultiplex node device, the optical device passes the node device as an optical signal. If it is a packet addressed to its own node device, it performs packet transfer control for branching in. Therefore, each optical node device receives the optical packet when it is inserted into the optical fiber transmission line. A label indicating information including the address to the destination node device or a route to the destination node device is generated, and the label is wavelength-multiplexed or polarization-multiplexed and sent out a predetermined time earlier than the optical packet corresponding to the optical fiber transmission path, Each optical node device receives this label and determines whether or not the corresponding packet is a packet addressed to its own node device ”. .

  According to the optical ring network of Patent Document 3, since optical packet signals are directly branched / inserted on the ring, high-speed optical packets can be accommodated more efficiently than SONET UPSR. A label indicating destination / route information must be created, and the label must be transferred to another node using a wavelength or polarization different from that of the optical packet signal, which makes the configuration of the optical node device complicated and expensive. There is a problem that. Further, since there is no function that enables autonomous return to a failure like SONET UPSR, this optical ring network does not solve the problem of network reliability.

  SONET UPSR enables autonomous recovery from failures by configuring each ring with two optical fibers. However, a ring is composed of one optical fiber, and two different optical signals are used for upstream and downstream optical signals. A method using a wavelength has also been proposed (see Patent Document 4). According to the optical ring network disclosed in Patent Document 4, “center optical node device 1 and a plurality of remote optical node devices 2-1 to 2-N are connected in a ring shape by one optical fiber 7, and the center optical node device is connected. 1 transmits downstream optical signals Sig1 addressed to the respective remote optical node devices 2-1 to 2-N in both the left and right directions, and the remote optical node devices 2-1 to 2-N download from the direction in which no failure has occurred. By receiving the optical signal Sig1 and transmitting the upstream optical signals Sig2-1 to Sig2-N in the direction of reception, it is possible to realize autonomous recovery from a failure in a single optical fiber ring. . However, while maintaining bidirectional optical signal transmission between the center optical node and each remote optical node using a single optical fiber, communication is maintained by switching the optical signal transmission direction and signal transmission timing in the event of a ring failure. Since the optical signal failure detection method, the optical signal transmission timing control method, and the transmission path switching method disclosed in the center optical node and each remote optical node are extremely complicated as compared with known methods such as SONET UPSR, The configuration of the center optical node device and each remote optical node device is complicated and expensive, and is not practical.

  Patent Document 5 proposes a one-way optical ring network in which different optical transmission wavelengths are assigned in advance to optical nodes, and communication between the optical nodes is performed by optical wavelength division multiplexing. According to this ring network, optical wavelength division multiplexing is used, so high-speed and wideband communication is possible, and since the optical signal format is not specified, the applicable range is wider than SONET UPSR, but only the number of optical nodes Since each optical node device needs to generate and process optical signals having different wavelengths, the configuration of each optical node device becomes complicated and the cost increases. Further, Patent Document 5 does not describe a function that enables an autonomous return to a failure, and this optical ring network does not solve the problem of network reliability.

  Patent Document 6 proposes a one-way optical ring network in which different optical transmission wavelengths are assigned to optical nodes in advance and communication between the optical nodes is performed by optical wavelength division multiplexing, as in Patent Document 5. . Although the method in which each optical node device generates and processes optical signals having different wavelengths corresponding to the number of optical nodes is different from Patent Document 5, the configuration of each optical node device is also complicated and the cost is increased. Although Patent Document 6 describes an example in which another fiber is provided to protect against an optical ring failure, it does not describe a specific method that enables recovery in the event of a failure. The network cannot be said to solve the network reliability problem.

  Patent Document 7 describes a failure in a two-fiber optical ring of SONET or SDH (Synchronous Digital Hierarchy: Synchronous Multiplexing Digital Hierarchy standardized by the International Telecommunications Union / Telecommunication Standardization Sector (ITU-TS) based on SONET in North America). As a method of further improving the recovery function and increasing the reliability of the network, a third optical fiber ring for failure recovery is added to the first and second optical fiber rings for normal signal transmission, and each optical node device A method has been proposed in which the connection state between the optical node device input / output units is switched according to the failure occurrence state on the first and second rings, and the failure section is detoured to the third ring. According to this proposed method, the reliability as a ring network is improved. However, one more optical fiber is required as compared with the two-fiber ring, and at the same time, the switching at the time of failure becomes more complicated than the SONET UPSR ring. Cost increases. Furthermore, since the switching control protocol defined by SONET (or SDH) is used for controlling switching at the time of failure, it cannot be applied to an optical packet ring network.

In a relatively large optical network in the metro area, both bandwidth-guaranteed traffic such as SONET (or SDH) and best-effort packet traffic such as Ethernet are efficiently handled according to service requirements. IEEE 802.17 Resilient Packet Ring has been standardized as an optical ring network that can be accommodated and has a recovery speed at the time of failure as high as that of a SONET (or SDH) ring network (see Non-Patent Document 3). However, each node device of the resilient packet ring needs to support both SONET (or SDH) physical layer interface and packet physical layer interface, so it is inevitable compared to optical packet ring that only needs to support packet traffic. However, there is a drawback that the configuration is greatly complicated and the cost of the apparatus becomes extremely high.
Japanese Patent Application No. 2004-329378 “Optical Access Network Method, Optical Access Network, and Optical Access Switch” Japanese Patent Application No. 2005-144423 “Optical Switch Device and Optical Access Network Method Using the Same” Japanese Patent Application Laid-Open No. 2001-244980 “Operation Method of Ultra High-Speed Optical Packet Forwarding Ring Network, Optical Insertion / Drop Type Multiplex / Demultiplex Node Device, and Optical Add / Drop Type Multiplex / Demultiplex Node Device” JP 2002-185485 “Optical Ring Network System, Optical Node Device, and Optical Ring Network System Redundancy Method” Signal Processing Method ” Japanese Patent Laid-Open No. 2001-257698 “Wavelength Division Multiplexing Optical Ring Network and Signal Processing Method” Special Table 2002-527990 "Optical Ring Network" JP 2001-16240 “Optical Ring Network” IEEE 802.3ah Draft Amendment to Carrier Sense Multiple Access with Collision Detection (CSMA / CD) Access Method and Physical Layer 3 Spec. GR-1400-CORE, “SONET Dual-FED Universal Path Switching Ring (UPSR) Equipment Generic Criteria”, Issue 2, (Bellcore, January, 1999). “IEEE 802.17 Resilient Packet Ring Tutoral”, IEEE Communications Magazine, March 2004, PP 112-118.

  The invention of the prior application 1 uses the features of GE-PON standardized for the purpose of realizing a broadband and low-cost packet communication service in an optical access network, the problem of transmission distance limitation in GE-PON, and downlink signal security. The invention of prior application 2 was made to improve the reliability of the optical access network according to the invention of prior application 1. Since each invention assumes a tree-like optical network structure as in GE-PON, the degree of freedom with respect to network use and physical shape (topology) is small as in GE-PON. Could not be resolved.

  On the other hand, various optical ring networks as described in the description of the background art have been proposed as optical networks having a large degree of freedom for network applications and topologies and excellent reliability. All ring networks have a problem in that the configuration and control of the ring node is complicated in order to transmit packet-based high-speed optical signals, and the apparatus becomes complicated and expensive.

  Therefore, the problem to be solved by the present invention is that while maintaining the features of the prior application 1 that solved some of the problems of GE-PON while maintaining the features of GE-PON that are broadband and low price, The prior application 1, the prior application 2, and the conventional optical ring network, which have the features that the degree of freedom of the network application and topology is large, the configuration of the node device is simple, low cost and high reliability, could not be realized. It is to provide a novel optical ring network device.

  As means for solving this problem, the optical ring network device of the present invention forms one optical ring network as a whole by the working route and the backup route, and is prepared for each optical ring node by the same control as in the prior application 1. The mx1 optical switch switches the optical signal in units of packets to perform communication between the center node and each terminal, and when an optical signal failure occurs on the working route, the optical signal path is changed from the working route in each optical ring node. Configure to switch to backup route.

More specifically, the optical ring network device of the present invention as means for solving this problem includes a center node having a working optical interface and a backup optical interface, a working route optical switch circuit, and a backup route optical switch circuit. , And n optical switch nodes N1, N2,..., Ni,..., Nn (i is from 2), each having an active / backup route switching optical switch circuit. any natural number up to n), from the working optical interface of the center node to the working route optical switch circuit of the optical switch node Nn, the intermediate optical switch nodes N1, N2,... Ni,. The working route is constructed by connecting each of the working route optical switch circuits of 1 with one optical fiber so as to pass through in this order. From the standby optical interface of the center node to the standby route optical switch circuit of the optical switch node N1, each backup route optical switch of each of the intermediate optical switch nodes Nn, Nn-1,... Nn-i + 1,. A spare route is constructed by connecting the circuits with one optical fiber so that the circuits pass in this order,
An optical ring network is configured as a whole by both the working route and the backup route,
If an optical signal failure occurs at one location on the working route, the working signal is detected at the optical switch node to which the working route optical switch circuit that first detected the failure of the optical signal belongs and all subsequent optical switch nodes. This is realized as an optical ring network device capable of maintaining communication between the center node and all the optical termination devices by switching the optical signal path from the working route to the standby route by the optical switch circuit for / backup route switching.

  In the optical ring network configuration method and optical ring network apparatus of the present invention, as means for realizing high reliability while maintaining the features of the prior application 1, the n optical switch nodes are respectively used as a working route optical switch circuit and a spare. A route optical switch circuit and a working / protection route switching optical switch circuit. Each of the n optical switch nodes has a working route optical switch circuit having a wavelength λ1 transmitted from the center node to the working route optical fiber by the working optical interface. Each downstream optical packet signal is received, and the downstream optical packet signal on the working route is centered by switching each working route optical switch circuit in units of optical packets based on specific information of the downstream optical packet signal on the working route. When the node reaches one optical termination device, A wavelength λ2 different from λ1 from the one optical terminator determined by the center node by switching each working route optical switch circuit in units of packets based on specific information of the downstream optical packet signal on the working route Are configured to reach the working optical interface of the center node via the working route optical fiber, and each of the spare optical switch circuits of the n optical switch nodes is protected by the spare optical interface. Each of the downstream optical packet signals of wavelength λ1 sent to the route optical fiber is received, and each backup route optical switch circuit is switched in units of optical packets based on specific information of the downstream optical packet signal on the backup route. One optical termination whose center node defines the above downstream optical packet signal By switching each backup route optical switch circuit in units of packets based on the specific information of the downstream optical packet signal on the backup route, from the one optical terminal device determined by the center node. An uplink signal having a wavelength λ2 different from λ1 is configured to reach the backup optical interface of the center node via the backup route optical fiber. If an optical signal failure occurs at one location on the current route, the optical signal The optical packet signal path between the center node and each optical terminating device is currently used by each active / protective route switching optical switch circuit at the optical switch node that first detects the failure of the network and all the optical switch nodes after that. By switching from the route to the backup route, communication between the center node and all optical termination devices So that can be maintained.

  In the optical ring network device of the present invention, an optical packet signal path between a center node and each optical terminating device is detected by detecting an abnormality at one location on the working route and using a working / backup route switching optical switch circuit. As a means for switching from the working route to the backup route, the working route optical switch circuit of each of the n optical switch nodes is transmitted, and the downstream optical packet signal of wavelength λ1 sent from the center node to the working route optical fiber by the working optical interface Received and detected whether there is an abnormality in the optical packet signal, and if there is an abnormality, the respective working / protection route switching optical switch circuit is switched to switch the path of the optical packet signal from the working route to the protection route. Constitute.

  In the optical ring network configuration method and the optical ring network device of the present invention, as means for simplifying and reducing the configuration of the optical ring node device by applying the control method of the prior application 1 to the control of the downlink signal and the uplink signal, The downstream optical packet signal of wavelength λ1 sent from the center node to the working route optical fiber by the working optical interface and the downstream optical packet signal of wavelength λ1 sent from the center node to the backup route optical fiber by the backup optical interface are defined by IEEE 802.3ah. As specific information of the downstream optical packet signal, LLID (Logical Link Identifier, logical link identifier) defined by IEEE 802.3ah, frame length, control message from the center node, and To include It is formed.

  Furthermore, in the optical ring network configuration method and the optical ring network device of the present invention, as a means for simplifying and reducing the configuration of the optical ring node device by applying the control method of the prior application 1 to the control of the downlink signal and the uplink signal. Based on the LLID specified by IEEE 802.3ah and the frame length, which is specific information of the downstream optical packet signal, the downstream optical packet signal is switched on a packet basis, and the specific information of the downstream optical packet signal is received from the center node. An upstream optical packet signal is switched in units of packets based on the control message.

  The optical ring network configuration of the present invention described above maintains the features of GE-PON, while maintaining the features of GE-PON such as wide bandwidth and low price, while maintaining the features of prior application 1 that solved the problems of GE-PON, In addition, it is possible to realize an optical network having the characteristics of a ring network that has a high degree of freedom with respect to topology. Furthermore, it is possible to realize a highly reliable optical network that can prevent communication failure due to a failure of an optical fiber or the like. That is, according to the present invention, there is no limitation on the number of optical terminators that can be easily and inexpensively connected with high reliability, which is difficult to realize with the prior application 1, the prior application 2, and the conventional optical ring network. It is possible to realize a broadband packet communication optical network that can be installed in a wide range and has a high degree of freedom in network configuration.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an embodiment (Example 1) of an optical ring network configuration method and an optical ring network device embodying the method of the present invention. The embodiment 1 in FIG. 1 includes a center node 3 having a working optical interface 1 and a protection optical interface 2, one working route optical switch circuit 4, one protection route optical switch circuit 5, and one working / N optical switch nodes N1, N2,..., Ni,..., Nn (i is an arbitrary number from 2 to n) each having a spare route changeover switch circuit 8 In the optical network 14 having the natural number 9), the optical switch nodes N1, N2,... Ni,... From the active optical interface 1 of the center node 3 to the active route optical switch circuit 4 of the optical switch node Nn. A working route 11 is formed by connecting each Nn-1 working route optical switch circuit 4 with one optical fiber 10 so as to pass through in this order, and the center node 3 to the standby route optical switch circuit 5 of the optical switch node N1, each of the backup route optical switches of the optical switch nodes Nn, Nn-1,... Nn-i + 1,. An optical ring network 14 is formed as a whole by connecting the circuit 5 with one optical fiber 12 so as to pass through in this order, thereby forming a single optical ring network 14, and an optical signal failure occurs at one location on the working route. Occurs, the optical signal path from the working route 11 is switched by the respective working / protection route switching optical switch circuits 8 at the optical switch node that first detected the failure of the optical signal and all the optical switch nodes thereafter. By switching to the backup route 13, communication between the center node 3 and all the optical termination devices 6 can be maintained. It is a thing. Here, the working / protection route changeover switch circuit 8 of each optical switch node includes the same number of optical signal switching circuits 15 as the arbitrary number of optical termination devices 6 accommodated in the switch node. The optical signal switching circuits 15 are connected to each other through one optical fiber 7. In the first embodiment of FIG. 1, the working route 11 is in the counterclockwise (counterclockwise) direction of the ring and the backup route 13 is in the clockwise (clockwise) direction of the ring. The route may be determined to be counterclockwise.

In the first embodiment of FIG. 1, as a means for realizing high reliability while maintaining the features of the prior application 1, the n optical switch nodes 9 are respectively used as the working route optical switch circuit 4 and the backup route optical switch circuit 5. And the working route optical switch circuit 4 of each of the n optical switch nodes 9 has a wavelength transmitted from the center node 3 to the working route optical fiber 10 by the working optical interface 1. Each downstream optical packet signal on the working route is received by receiving each downstream optical packet signal of λ1 and switching each working route optical switch circuit 4 in units of optical packets based on specific information of the downstream optical packet signal on the working route. To the single optical termination device 6 determined by the center node 1 and the downstream optical packet on the working route. By switching each active route optical switch circuit 4 on a packet basis based on specific information of the optical signal, an upstream signal having a wavelength λ2 different from λ1 from the one optical termination device 6 determined by the center node 3 is obtained. The standby route optical switch circuit 5 of each of the n optical switch nodes 9 is configured so that the center node 3 is connected to the standby optical interface. 2 receives the downstream optical signal packet of wavelength λ1 sent to the backup route optical fiber 12, and sets each backup route optical switch circuit 5 in units of optical packets based on the specific information of the downstream optical packet signal on the backup route. By switching, the downstream optical packet signal on the backup route is changed to one optical terminal determined by the center node 3. The one optical device determined by the center node 3 is made to reach the end device 6 and switch each backup route optical switch circuit 5 in units of packets based on specific information of the downstream optical packet signal on the backup route. An uplink signal having a wavelength λ2 different from λ1 from the terminating device 6 is configured to reach the backup optical interface 2 of the center node 3 via the backup route optical fiber 12, and an optical signal failure occurs at one point on the working route. Occurs in the optical switch node that first detected the failure of the optical signal and in all subsequent optical switch nodes, the respective active / backup route switching optical switch circuits 8 cause the center node and each optical terminating device to By switching the route of the optical packet signal between the working route to the backup route, To be able to maintain communication between the termination device.

  In the first embodiment of FIG. 1, it is detected that an abnormality has occurred at one place on the working route, and the path of the optical packet signal between the center node and each optical terminating device is detected by the working / backup route switching optical switch circuit. As means for switching from the working route to the protection route, the center node 3 sends the working route optical switch circuit 4 of each of the n optical switch nodes 9 in the embodiment of FIG. 1 to the working route optical fiber 10 by the working optical interface 1. Each of the downstream optical packet signals having the wavelength λ1 is received and it is detected whether or not there is an abnormality in the optical packet signal. If there is an abnormality, the working / protection route switching optical switch circuit 8 is switched to switch the optical packet signal. The route is configured to switch from the working route to the backup route.

  In the first embodiment shown in FIG. 1, the center node 3 is used as a means for reducing the configuration of the optical ring node device by applying the control method of the prior application 1 to the downlink signal and uplink signal control. 1, a downstream optical packet signal of wavelength λ1 sent to the working route optical fiber 10 and a downstream optical packet signal of wavelength λ1 sent by the center node 3 to the backup route optical fiber through the backup optical interface 2 are frames defined by IEEE 802.3ah. It has a configuration and is configured to include LLID defined by IEEE 802.3ah, a frame length, and a control message from the center node as specific information of the downstream optical packet signal.

  Further, in the first embodiment of FIG. 1, as a means for simplifying and reducing the cost of the configuration of the optical ring node device by applying the control method of the prior application 1 to the control of the downlink signal and the uplink signal, the identification of the downlink optical packet signal is performed. The downstream optical packet signal is switched in units of packets based on the LLID defined in IEEE 802.3ah and the frame length, and upstream optical based on the control message from the center node that is specific information of the downstream optical packet signal. The packet signal is configured to be switched on a packet basis.

  In addition, it is necessary to switch the working / standby in each optical switch node for each of the downstream optical signal having the wavelength λ1 and the upstream optical signal having the wavelength λ2 for each optical termination device 6 accommodated in the switch node. is there. Therefore, the working / backup route switching optical switch circuit 8 in FIG. 1 requires the same number of optical signal switching circuits 15 as the number of optical termination devices 6 accommodated in the optical switch node as shown in FIG. Each of the signal switching circuits 15 includes one downstream signal switching 2 × 1 optical switch, one upstream signal switching 2 × 1 optical switch, and one optical demultiplexer / multiplexer. This configuration will be described in detail in the description of FIG.

  The embodiment of the optical ring network device of the present invention has been described above with reference to the first embodiment of FIG. 1, but the operation of the optical ring network device of the present invention is further illustrated by FIG. 6, which is a simplified model of FIG. 1. I will explain it.

  FIG. 6 shows that the number of optical switch nodes 9 in the first embodiment of FIG. 1 is four from the node N1 (609-1) to the node N4 (609-4), and the optical termination device 6 connected to each optical switch node. The number of nodes is one for each optical switch node (606-1, 606-2, 606-3, 606-4). In this example, the working / protection route switching optical switch circuit (8 in FIG. 1) of each optical switch node becomes one optical signal switching circuit (15 in FIG. 1) itself (608-1, 608-2). 608-3, 608-4). FIG. 6 illustrates a case where a transmission path failure occurs at the failure occurrence point 620. The above assumptions are merely for the sake of explanation. The generality of the first embodiment in which the number n of optical switch nodes and the number of optical termination devices connected to each optical switch node are arbitrary is as follows. Note that this assumption is not lost.

  In FIG. 6, for further simplification, the working optical interface 601 of the center node 603 has a wavelength λ1 addressed to the optical terminating device 606-1 connected to the optical switch node N1 (609-1) on the working route optical fiber 611. Downstream optical packet signal A (621), downstream optical packet signal B (622) of wavelength λ1 addressed to optical termination device 606-2 connected to optical switch node N2 (609-2), optical switch node N3 (609-3) ) Connected to the optical terminating device 606-3 connected to the optical terminating device 606-3 and the wavelength λ1 addressed to the optical terminating device 606-4 connected to the optical switch node N4 (609-4). Assume that the downstream optical packet signal D (624) is transmitted. Each of the optical terminators 606-1, 606-2, 606-3, and 606-4 receives the upstream optical packet signal a (625) having the wavelength λ2 and the upstream light having the wavelength λ2 addressed to the working optical interface 601 of the center node 603. The packet signal b (626), the upstream optical packet signal c (627) of the wavelength λ2, and the upstream optical packet signal d (628) of the wavelength λ2 are converted into the working / backup route switching optical switch circuit 608-1 of each optical switch node, Assume that the data is sent to 608-2, 608-3, and 608-4, respectively.

  Further, the backup optical interface 602 of the center node 603 is connected to the optical terminal node 606-1 connected to the optical switch node N1 (609-1) on the backup route optical fiber 613, and the downstream optical packet signal A (having the wavelength λ1). 629), downstream optical packet signal B (630) of wavelength λ1 addressed to the optical termination device 606-2 connected to the optical switch node N2 (609-2), optical connected to the optical switch node N3 (609-3) Downstream optical packet signal C (631) of wavelength λ1 addressed to termination device 606-3 and downstream optical packet signal D of wavelength λ1 addressed to optical termination device 606-4 connected to optical switch node N4 (609-4) 632) is transmitted.

  Here, each of the downstream optical packet signals A (621), B (622), C (623), and D (624) transmitted from the working optical interface 601 of the center node 603 to the working route optical fiber 611, and the backup optical interface 602. The downstream optical packet signals A (629), B (630), C (631), and D (632) transmitted from the optical fiber to the backup route optical fiber 613 are (621 and 629, 622 and 630, 623 and 631, respectively). 624 and 632) are optical packet signals having exactly the same information.

  When the ring network of FIG. 6 is operating normally, the working route optical switch circuit 604-1 of the optical switch node N1 (6091) receives the downstream optical packet signal A (621) from the working route optical fiber 611. Upon reception, it is determined that the optical packet signal A is a signal addressed to the optical termination device 1 based on specific information (LLID and frame length defined in IEEE 802.3ah) in the optical packet signal, and the optical packet signal The output of the working route optical switch circuit 604-1 is sent to the working / standby switching optical switch 608-1 only for the time period A continues. Since the ring network is operating normally, the working / standby switching optical switch 608-1 is connected to the working side, and the optical packet signal A is transmitted to the optical terminating device 1. The working route optical switch circuit 604-1 of the optical switch node N1 (609-1) continues to receive the optical packet signals B (622), C (623), and D (624) from the working route optical fiber 611. The optical switch circuit 604-1 uses the optical termination device 1 connected to the optical switch node N1 according to specific information (LLID and frame length defined in IEEE802.3ah) in each optical packet signal. It is determined that the optical signal is not addressed to (606-1), and the output optical packet signal of the optical switch circuit 604-1 is sent to the optical switch node N2 (609-2) of the next stage for the time that each optical packet signal continues. ) To the working route optical fiber 633 connected to the working route optical switch circuit 604-2.

  When the ring network is operating normally, the same operation is executed in each of the working route optical switch circuits 604-2, 604-3, and 604-4 of the optical switch nodes N2, N3, and N4, and the optical packet signal B , C, and D are delivered to the optical termination device 2 (606-2), the optical termination device 3 (606-3), and the optical termination device 4 (606-4), respectively.

  The working optical interface 601 of the center node 603 includes a control message as specific information in order to control the upstream optical packet signals of wavelength λ 2 transmitted by each optical terminating device so as not to collide with each other on the working route optical fiber 611. A downstream optical packet signal (not shown in FIG. 6) is periodically transmitted to each optical termination device, and the working route optical switch circuit 604-1 of the optical switch node N1 (609-1) When an optical packet signal including a control message addressed to the device 1 (606-1) is received from the optical fiber 611, the optical termination is started from the time assigned to the optical termination device 1 (606-1) based on the control message. The output signal of the working / standby switching optical switch 608-1 is accepted only for the duration assigned to the apparatus 1 (606-1). Since the working / standby switching optical switch 608-1 is connected to the working side, the upstream optical packet signal a (625) of the wavelength λ2 transmitted by the optical terminating device 606-1 is thereby transmitted to the other optical terminating device (606). -2, 606-3, 606-4) on the working route optical fiber 611 via the working / standby switching optical switch 608-1 and the working route optical switch circuit 604-1 without colliding with the upstream optical packet signal. And is delivered to the working optical interface 601 of the center node 603.

  When the ring network is operating normally, the same operation is executed in each of the working route optical switch circuits 604-2, 604-3, and 604-4 of the optical switch nodes N2, N3, and N4. Optical packet signal b (626) from (606-2), optical packet signal c (627) from optical terminator 3 (606-3), and optical packet signal d (from optical terminator 4 (606-4)) 628) is sent out on the working route optical fiber toward the working route optical switch circuit of the preceding-stage switch node between the time assigned to each and the duration time assigned to each. In this way, all the upstream optical packet signals a, b, c, and d are delivered on the working route optical fiber 611 toward the working optical interface 601 of the center node 603 without colliding with each other.

  The operation of the backup route optical switch circuit (605-1, 605-2, 605-3, 605-4) connected to the backup route is the same as that of the active route optical switch circuit (604-1, The operation is performed in exactly the same manner as described above for 604-2, 604-3, and 604-4). That is, when the ring network is operating normally, the downstream optical packet signals A (629), B (630), and C (631) having the wavelength λ1 from the backup optical interface 602 of the center node 603 to the backup route optical fiber 613. , D (632) is sent, the backup route optical switch circuit 605-1 of the optical switch node N1 (609-1) sends the downstream optical packet signal A to the active / backup switch optical switch 608-1, and the optical switch The protection route optical switch circuit 605-2 of the node N2 (609-2) sends the downstream optical packet signal B to the working / protection switching optical switch 608-2, and the protection route optical switch circuit of the optical switch node N3 (609-3). 605-3 sends the downstream optical packet signal C to the working / standby switching optical switch 608-3, and the optical switch node N4 ( The backup route optical switch circuit 605-4 of 609-4) sends the downstream optical packet signal A to the working / standby switching optical switch 608-4. However, since the respective working / protection route switching optical switch circuits (608-1, 608-2, 608-3, 608-4) are all connected to the working side, these downstream optical packet signals are transmitted to the respective optical terminations. It is not transmitted to the devices (606-1, 606-2, 606-3, 606-4). In addition, upstream optical packet signals a (625), b (626), c (627), and d (628) of wavelength λ2 from each optical termination device are respectively used / working route switching optical switches connected to the working side. Since they are interrupted by the circuit, none of them are sent out on the backup route optical fiber 613.

  Next, consider a case where a failure (for example, disconnection of the working and backup optical fibers) occurs at a point indicated by reference numeral 620 on the optical ring network in FIG. At this time, since the working route is connected to the optical switch node N1 (609-1) and the optical switch node N2 (609-2) without any trouble, the working route optical switch circuit (604-1, 604-2) operates in exactly the same way as during normal operation of the entire optical fiber ring, and the working / backup route switching optical switch circuit remains connected to the working side. Accordingly, the downstream optical packet signals A (621) and B (622) are sent to the respective optical termination devices (606-1, 606-2) via the working route indicated by the thick line in FIG. Upstream optical packet signals a (625) and b (626) from the terminating devices (606-1, 606-2) are respectively sent to the working optical interface 601 of the center node 603 via the working route indicated by the bold line. .

  The working route optical switch circuit 604-3 of the optical switch node N3 (609-3) detects an abnormality because the downstream optical packet signal does not reach due to a failure at the failure point 620, and reserves the working / standby switching optical switch 608-3. Switch to the side. The working route optical switch circuit 604-4 of the optical switch node N4 (609-4) also detects an abnormality because the downstream optical packet signal from the optical switch node N3 (609-3) does not reach, and switches between active and standby. The optical switch 608-4 is switched to the spare side. As a result, the downstream optical packet signals C (631) and D (632) transmitted from the backup optical interface 602 of the center node 603 onto the backup route optical fiber 613 are transmitted via the backup route indicated by a thick line in FIG. The upstream optical packet signals c (627) and d (628) from the respective optical termination devices (606-3, 606-4) are sent to the respective optical termination devices (606-3, 606-4), respectively. The data is sent to the backup optical interface 602 of the center node 603 via the backup route indicated by a thick line.

  With the configuration and operation described above, when an optical signal failure occurs at one location (620) on the working route, the optical switch node (N3, 609-3) that first detected the failure of the optical signal and thereafter In each of the optical switch nodes (N4, 609-4), the center node (603) and the respective optical terminal devices (606-3) are switched by the respective working / backup route switching optical switch circuits (608-3, 608-4). , 606-4) by switching the path of the optical packet signal from the working route to the backup route, and thereby the center node (603) and all the optical termination devices (606-1, 606-2, 606-3, 606). It becomes possible to maintain communication with 4).

  Next, the configuration of the optical switch node and the operation of each part in the optical ring network device of the present invention will be described in detail with reference to the configuration example of the optical switch node shown in FIG. In FIG. 7, the number (m−1) of arbitrary optical termination devices connected to one optical switch node is 3, but this is merely for the sake of explanation and drawing simplicity and is limited to this value. It is not a thing. In addition, the configuration example of the figure is drawn for the i-th optical switch node Ni in the optical ring network of the present invention of FIG. 1 and is applied to the optical switch node at any position on the ring. Which is the second optical demultiplexer / multiplexer 705 in the working route optical switch circuit 701 of the optical switch node Nn and the second optical demultiplexer / multiplexer 716 in the backup route optical switch circuit 702 of the optical switch node N1? Since there is no next-stage optical switch node to be connected, there is no need to mount it.

  The optical switch node Ni in FIG. 7 includes a working route optical switch circuit 701, a backup route optical switch circuit 702, and a working / backup route switching optical switch circuit 703. The working route optical switch circuit 701 includes first and second optical switches. Demultiplexer / multiplexers 704 and 705, one optical branching unit 706, one optical delay circuit 707, one optical input / output terminal and m (m is connected to each optical switch node) The first and second mx1 optical switches 708 and 709 having the optical input / output terminals of 4) in the case of FIG. 7 with an arbitrary number of optical terminators to be added + 1, one optical / electrical conversion circuit 710, 1 Each frame analysis circuit 711, one downstream signal switch control circuit 712, one upstream signal switch control circuit 713, and one abnormality detection circuit 714, and the backup route optical switch circuit 702 includes , First and second optical demultiplexers / multiplexers 715 and 716, one optical branching device 717, one optical delay circuit 718, one optical input / output terminal and m optical lights, respectively. First and second mx1 optical switches 719 and 720 having input / output terminals, one optical / electrical conversion circuit 721, one frame analysis circuit 722, one downstream signal switch control circuit 723, And an active / preliminary switching optical switch circuit 703 includes m−1 downstream signal switching 2 × 1 switches 725, 726, and 727 and m−1 upstream signal switching. 2 × 1 switches 728, 729, 730 and m−1 optical demultiplexers / multiplexers 731 732, 733 connected to m−1 optical terminators (not shown), respectively. It is configured.

  In the active / standby switching optical switch circuit 703 of FIG. 7, one downstream signal switching 2 × 1 optical switch 725, one upstream signal switching 2 × 1 optical switch 730, and one optical demultiplexer / multiplexer 733 are used. The optical signal switching circuit (the optical signal switching circuit 15 in FIG. 1) is configured. Similarly, the downstream signal switching 2 × 1 optical switch 726, the upstream signal switching 2 × 1 optical switch 729, and the optical demultiplexer / multiplexer 732 are used for one light. A signal switching circuit is configured, and one optical signal switching circuit is configured by the downstream signal switching 2 × 1 optical switch 727, the upstream signal switching 2 × 1 optical switch 728, and the optical demultiplexer / multiplexer 731.

In the optical switch node of FIG. 7, the configuration and operation of the working route optical switch circuit (portion 701 surrounded by a broken line in FIG. 7) are as follows.
First, the downstream optical packet signal of wavelength λ 1 on the working route optical fiber 734 is demultiplexed by the first optical demultiplexer / multiplexer 704 and then branched into two by the optical branching unit 706. One of the downstream optical packet signal outputs is delayed by a predetermined time by the optical delay circuit 707, and then one side terminal of the first mx1 optical switch 708 (in this patent, m terminals and one terminal are connected). In an mx1 optical switch for switching the interconnection between the two, one of the m terminals is called an m-side terminal, and one terminal interconnected with any one of the m-side terminals is called a 1-side terminal) Is done.

  The other downstream optical packet signal output branched into two by the optical splitter 706 is converted into two electrical packet signals by the optical / electrical conversion circuit 710, and one of the electrical packet signals is input to the frame analysis circuit 711. .

  The LLID and frame length information in the frame of the electrical packet signal input to the frame analysis circuit 711 are extracted as specific information by the frame analysis circuit 711 and input to the downlink signal switch control circuit 712, and input to the frame analysis circuit 711. A control message from the center node in the electrical packet signal frame is extracted as specific information by the frame analysis circuit 711 and input to the upstream signal switch control circuit 713.

  The downstream optical packet signal of wavelength λ1 input to the one-side terminal of the first mx1 optical switch 708 is switched in units of optical packets based on the LLID and frame length information by the downstream signal switch control circuit 712, and the second The optical demultiplexer / multiplexer 705 or the working / protection route switching optical switch circuit 703 is connected to one of the two side terminals of the m−1 downlink signal switching 2 × 1 optical switches (725, 726, 727), respectively.

  The upstream optical packet signal of wavelength λ2 on the working route optical fiber 735 is demultiplexed by the second optical demultiplexer / multiplexer 705 and then connected to one of the m-side terminals of the second mx1 optical switch 709, One of the 2 side terminals of the m-1 upstream signal switching 2x1 optical switches (728, 729, 730) is connected to the remaining m-1 m side terminals of the second mx1 optical switch 709, respectively. The upstream optical packet signal of wavelength λ2 input to m m-side terminals of the mx1 optical switch 709 is switched by the upstream signal switch control circuit 713 in units of optical packets based on a control message from the center node. The optical demultiplexer / multiplexer 704 is input and combined, and is transmitted as an upstream optical packet signal of wavelength λ 2 on the working route optical fiber 734.

  In order for the downstream optical packet signal of wavelength λ1 to be switched in units of optical packets by the first mx1 optical switch 708 based on the LLID and frame length information of the packet itself, an optical / electrical conversion circuit 710, a frame analysis circuit 711, and It is necessary to delay the downstream optical packet signal of wavelength λ1 entering the first mx1 optical switch 708 by the delay time of the signal processing by the downstream signal switch control circuit 712. The optical delay circuit 707 of FIG. 7 is for that purpose, and is realized by, for example, an optical fiber having an appropriate length.

In the optical switch node of FIG. 7, the configuration and operation of the backup route optical switch circuit (portion 702 surrounded by a broken line in FIG. 7) are as follows.
The downstream optical packet signal of wavelength λ 1 on the backup route optical fiber 736 is demultiplexed by the first optical demultiplexer / multiplexer 715 and then branched into two by the optical branching unit 717. One of the downstream optical packet signal outputs is delayed by a predetermined time by the optical delay circuit 718 and then input to the one-side terminal of the first mx1 optical switch 719. The other downstream optical packet signal output branched into two by the optical splitter 717 is converted into an electrical packet signal by the optical / electrical conversion circuit 721 and then input to the frame analysis circuit 722. The LLID and frame length information in the electrical packet signal frame input to the frame analysis circuit 722 are extracted as specific information by the frame analysis circuit 722 and input to the downlink signal switch control circuit 723. A control message from the center node in the electrical packet signal frame input to the frame analysis circuit 722 is extracted as specific information by the frame analysis circuit 722 and input to the upstream signal switch control circuit 724, and the first mx1 optical switch 719 is received. The downstream optical packet signal of wavelength λ1 input to the one side terminal of the first optical fiber is switched by the downstream signal switch control circuit 723 in units of optical packets based on the LLID and frame length information, and the second optical demultiplexer / multiplexer 716 is switched. Alternatively, the active / spare route switching optical switch circuit 703 is connected to the other of the two side terminals of the m−1 downlink signal switching 2 × 1 optical switches (725, 726, 727). The upstream optical packet signal of wavelength λ2 on the backup route optical fiber 737 is demultiplexed by the second optical demultiplexer / multiplexer 716 and then connected to one of the m-side terminals of the second mx1 optical switch 720, The other of the 2 side terminals of the m-1 upstream signal switching 2x1 optical switches (728, 729, 730) is connected to the remaining m-1 m side terminals of the second mx1 optical switch 720, respectively. The upstream optical packet signal of wavelength λ2 input to the m m-side terminals of the mx1 optical switch 720 is switched by the upstream signal switch control circuit 724 in units of optical packets based on the control message from the center node. The optical demultiplexer / multiplexer 715 is input and combined, and is transmitted as an upstream optical packet signal of wavelength λ 2 on the backup route optical fiber 736.

  In the working / protection route switching optical switch circuit 703, one terminal of m−1 downstream signal switching 2 × 1 optical switches (725, 726, 727) and m−1 upstream signal switching 2 × 1 optical switches (728, 729, 730) are connected to m-1 optical demultiplexers / multiplexers (731, 732, 733) connected to m-1 optical terminators (not shown), respectively. Configured to be connected. The anomaly detection circuit 714 of the working route optical switch circuit 701 receives the other electric packet signal converted into the electric packet signal by the optical / electrical conversion circuit 710 of the working route optical switch circuit 701, and receives the downstream optical packet of wavelength λ1. When it is detected that there is an abnormality in the signal, the two side terminals of the m−1 downlink signal switching 2 × 1 optical switch (725, 726, 727) and the m−1 uplink signal switching 2 × 1 optical switch (728, 729, 730) are switched at the same time from the working route side to the backup route side.

  There are various methods for detecting an abnormality in the abnormality detection circuit 714. As a simple method, for example, when the average power of the input electric packet signal is measured for a certain period of time and the level becomes lower than a predetermined threshold, an abnormality is detected. Just judge.

  With the above configuration and operation, if there is an abnormality in the downstream optical packet signal of wavelength λ1 received by the working route optical switch circuit 701 of the optical switch node Ni in FIG. 7, the route of the optical packet signal is switched from the working route to the backup route. Thus, it is possible to maintain communication between the center node and all the optical termination devices.

  In the optical switch node of FIG. 7, the first and second mx1 optical switches (708, 709) of the working route optical switch circuit 701 and the first and second mx1 optical switches (719, 719) of the standby route optical switch circuit 702 are used. 720) can each be configured as one optical switch element, but can also be configured by connecting 2 × 1 optical switches having the same structure in a multi-stage tree form as shown in FIG. FIG. 8 shows an example of m = 4 corresponding to FIG. 7, and 4 × 1 having four m-side terminals 802, 803, 804, 805 and one one-side terminal 806 shown on the upper side of FIG. The optical switch 801 may be realized by connecting three 2 × 1 optical switches 807, 808, and 809 in a two-stage tree shape as shown in the lower side of FIG. As such an optical switch element, a known optical waveguide switch using a ferroelectric such as lithium niobate can be used. Further, a known optical switch element having a structure using a semiconductor substrate or a glass substrate may be used.

  These optical switch elements need to operate at a high speed because the optical packet signal is switched in units of packets, but do not necessarily have to operate at the bit rate of the GE-PON optical packet signal (about 1 nsec). Since the minimum interval between GE-PON packets (interframe gap, IFG) is determined to be 12 bytes (96 bits), it is sufficient if switching can be completed with a margin within this time (about 100 nsec for GE-PON). A known optical switch element can be sufficiently used.

  As described above, in the optical ring network configuration method and the optical ring network apparatus according to the present invention, the optical signal is switched in units of packets by the mx1 optical switch in each optical switch node in the same manner as the invention of the prior application 1. Since communication is performed between each optical termination device, attenuation of the optical signal along the path from the center node to the optical termination device connected to each optical switch node must be branched by the number of optical termination devices by the optical splitter. Compared to the case of GE-PON, which is very small, even if the number of optical termination devices increases, the increase in optical signal attenuation is small. Accordingly, it is possible to flexibly configure a large-scale and geographically wide-range optical network by accommodating an arbitrary number of optical termination devices in each of a plurality of optical switch nodes.

  However, in the optical ring network of FIG. 1, for example, an optical signal transmitted through a route from the center node to the optical terminal connected to the farthest optical switch node Nn via the working route is an optical fiber of n sections. Therefore, when the number n of optical ring nodes is large (for example, 4 or more), it is difficult to receive signals correctly at the optical switch node far from the center node. There is.

  Specifically, in the case of Example 1 in FIG. 7, the attenuation of the optical signal in one optical switch node is the first and the second for the downstream signal of wavelength λ1 transmitted on the working route or the backup route. Of two optical demultiplexers / multiplexers (704, 705 or 715, 716), optical splitter (706 or 717), optical delay circuit (707 or 718), and first mx1 optical switch (708 or 719) It is the sum of the amount of attenuation by each. Similarly, the first and second optical demultiplexers / multiplexers (704, 705 or 715, 716), and the second mx1 light for the upstream signal of wavelength λ2 transmitted on the working route or the backup route This is the total sum of attenuation by each of the switches (709 or 720). Therefore, for example, the n-th optical switch node from the center node receives the optical signal which has been attenuated by the above-mentioned n times and attenuated by the optical fiber in the middle. When the number of switch nodes is large, the signal is correctly received. May be difficult.

  Accordingly, the second embodiment (embodiment 2) of the present invention provides a configuration of an optical switch node for removing the above-described limitation on the number n of optical switch nodes in the optical ring network device of the present invention.

  In Example 2 of the optical ring network device of the present invention, one of the m-side terminals of the first mx1 optical switch and the second optical demultiplexing / multiplexing in each of the working route optical switch circuits of the n optical switch nodes. And between each of the m-side terminals of the first mx1 optical switch and the second optical demultiplexer / multiplexer in each spare route optical switch circuit of each of the n optical switch nodes. An optical amplifier having a wavelength λ1 is provided, and there are n terminals between the one side terminal of the second mx1 optical switch and the first optical demultiplexer / multiplexer in the working route optical switch circuit of each of the n optical switch nodes. Each optical amplifier having a wavelength λ2 is provided between the one-side terminal of the second mx1 optical switch and the first optical demultiplexer / multiplexer in each backup route optical switch circuit of each of the optical switch nodes. As a specific example, FIG. 9 shows a configuration when the second embodiment of the present invention is applied to the configuration example (FIG. 7) of the optical switch node Ni in the first embodiment of the present invention. These optical amplifiers can be realized by a known technique such as a fiber amplifier using a nonlinear optical fiber doped with erbium or a semiconductor amplifier using a semiconductor element.

  In FIG. 9, in the working route optical switch circuit 901 of the optical switch node Ni, between one of the m-side terminals of the first mx1 optical switch 908 and the second optical demultiplexer / multiplexer 905, and of the optical switch node Ni Optical amplifiers 930 and 931 each having a wavelength λ1 are provided between one of the m-side terminals of the first mx1 optical switch 919 and the second optical demultiplexer / multiplexer 916 in the backup route optical switch circuit 902, Between the one-side terminal of the second mx1 optical switch 909 and the first optical demultiplexer / multiplexer 904 in the working route optical switch circuit 901 of the optical switch node Ni, and the backup route optical switch circuit 902 of the optical switch node Ni The optical amplifiers 932 and 933 each having a wavelength λ2 are provided between the one-side terminal of the second mx1 optical switch 920 and the first optical demultiplexer / multiplexer 915.

  In the above configuration, by setting the optical amplification gains of the optical amplifiers 930, 931, 932, and 933 large enough to at least compensate for the optical signal loss in the optical switch node, the number of optical switch nodes in the optical ring network device of the present invention The restriction on n can be removed. As a result, it is possible to realize a broadband packet communication optical network that can be installed in a geographically wider range than in the first embodiment and has a greater degree of freedom in network configuration.

  When these optical switches and optical amplifiers are realized as semiconductor elements, it is possible to further simplify and reduce the cost of the apparatus by realizing the optical switch and optical amplifier as an integrated element in the above configuration. Become. Specifically, the first mx1 optical switch and one optical amplifier with wavelength λ1 in the working route optical switch circuit, the first mx1 optical switch and one optical amplifier with wavelength λ1 in the backup route optical switch circuit, At least one of the second mx1 optical switch and one optical amplifier of wavelength λ2 in the root optical switch circuit, and the second mx1 optical switch and optical amplifier of one wavelength λ2 in the backup root optical switch circuit The combination is configured using an element in which the mx1 optical switch and the optical amplifier are integrated.

It is a figure which shows the Example (Example 1) of this invention. It is a figure which shows the conventional Gigabit Ethernet PON. (A), (b) It is a figure which shows the structural example of the optical access network by the prior application 1. FIG. (A), (b) It is a figure which shows the structural example of the optical access network by the prior application 2. FIG. It is a figure which shows the conventional UPSR. FIG. 3 is a diagram illustrating a diagram illustrating Example 1; FIG. 3 is a diagram illustrating a configuration example of an optical switch node according to the first embodiment. It is a figure which shows the structural example of an mx1 optical switch. It is a figure which shows the Example (Example 2) of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Active optical interface 2 Backup optical interface 3 Center node 4 Active route optical switch circuit 5 Backup route optical switch circuit 6 Optical termination device 7 Optical fiber 8 Active / backup route switching optical switch circuit 9 Optical switch node 10, 12 Optical fiber 11 Active Route 13 Backup route 14 Optical network 15 Optical signal switching circuit 200 Center node 201 Optical termination device (OLT)
202 Optical termination unit (ONU)
203 GE-PON
204, 206 Optical fiber 205 Splitter 207 Upper network 208 Internet etc. 209 User terminal 301 Center device 302 Remote device 303 Optical switch 304 Optical fiber (feeder section)
310, 311 Optical switch 312 Tree network 313 Optical fiber 401 Center device 402 Remote device 403 Optical switch 404 Working optical fiber 405 Backup optical fiber 406 Working network interface 407 Backup network interface 410, 411 Optical switch 412 Tree network 413 Working optical fiber 414 Standby optical fiber 500, 501, 502, 503 Ring node 510, 511 Optical fiber 512 Failure point 513, 514 Optical signal route 601 Working optical interface 602 Standby optical interface 603 Center node 604-1, 604-2, 604-3, 604-4 Active route optical switch circuit 605-1, 605-2, 605-3, 605-4 Backup route optical switch Circuits 606-1, 606-2, 606-3, 606-4 Optical terminators 608-1, 608-2, 608-3, 608-4 Working / protection route switching optical switch circuits 609-1, 609-2, 609-3, 609-4 Optical switch node 620 Failure occurrence point 621 Downstream optical packet signal A
622 Downlink optical packet signal B
623 Downstream optical packet signal C
624 Downstream optical packet signal D
625 Upstream optical packet signal a
626 Upstream optical packet signal b
627 Upstream optical packet signal c
628 Uplink optical packet signal d
629 Downstream optical packet signal A
630 Downstream optical packet signal B
631 Downstream optical packet signal C
632 Downstream optical packet signal D
633 working route optical fiber 701 working route optical switch circuit 702 backup route optical switch circuit 703 working / backup route switching optical switch circuit 704 first optical demultiplexing / multiplexing unit 705 second optical demultiplexing / multiplexing unit 706 light Branching unit 707 Optical delay circuit 708 First mx1 optical switch 709 Second mx1 optical switch 710 Optical / electrical conversion circuit 711 Frame analysis circuit 712 Downstream signal switch control circuit 713 Upstream signal switch control circuit 714 Abnormality detection circuit 715 First Optical demultiplexing / multiplexing device 716 Second optical demultiplexing / multiplexing device 717 Optical branching device 718 Optical delay circuit 719 First mx1 optical switch 720 Second mx1 optical switch 721 Optical / electrical conversion circuit 722 Frame analysis circuit 723 Downlink signal switch control circuit 724 Uplink signal switch control circuit 7 5, 726, 727 Downlink signal switching 2x1 switch 728 729, 730 Uplink signal switching 2x1 switch 731, 732, 733 Optical demultiplexer / multiplexer 734, 735 Current route optical fiber 736, 737 Backup route optical fiber 801 4x1 light Switch 802, 803, 804, 805 m side terminal 806 1 side terminal 807, 808, 809 2 × 1 optical switch 901 working route optical switch circuit 902 spare route optical switch circuit 903 working / protection route switching optical switch circuit 904 first optical component Wave / Multiplexer 905 Second optical demultiplexer / multiplexer 908 First mx1 optical switch 909 Second mx1 optical switch 915 First optical demultiplexer / multiplexer 916 Second optical demultiplexer / multiplexer Wave 919 First mx1 optical switch 920 Second mx1 optical switch 930 931 optical amplifier of the optical amplifier 932 and 933 wavelengths λ2 wavelength λ1

Claims (10)

A center node with a working optical interface and a standby optical interface;
N (n is an arbitrary integer greater than or equal to 2) optical switch nodes N1, N2,... Each having an active route optical switch circuit, a backup route optical switch circuit, and a current / backup route switching optical switch circuit. Between Ni,... Nn (i is an arbitrary natural number from 2 to n),
From the working optical interface of the center node to the working route optical switch circuit of the optical switch node Nn, the working route optical switch circuits of the intermediate optical switch nodes N1, N2,... Ni,. Configure the working route by connecting with one optical fiber so that it goes through in order,
From the standby optical interface of the center node to the standby route optical switch circuit of the optical switch node N1, the backup route optical switch circuits of the optical switch nodes Nn, Nn-1,... Nn-i + 1,. Configure a backup route by connecting with a single optical fiber so that
An optical ring network is configured as a whole by both the working route and the backup route,
If an optical signal failure occurs at one location on the working route, the working signal is detected at the optical switch node to which the working route optical switch circuit that first detected the failure of the optical signal belongs and all subsequent optical switch nodes. An optical ring network device that can maintain communication between the center node and all the optical termination devices by switching the optical signal path from the active route to the backup route by the optical switch circuit. The optical ring network device according to claim 1,
Each active route optical switch circuit of each of the n optical switch nodes receives the downstream optical packet signal of wavelength λ1 sent from the center node to the active route optical fiber through the active optical interface, and specific information of the downstream optical packet signal Based on the above, each of the working route optical switch circuits is switched in units of optical packets so that the downstream optical packet signal on the working route reaches one optical terminator determined by the center node, and the downstream optical packet on the working route By switching each working route optical switch circuit in units of packets based on the specific information of the signal, an upstream signal having a wavelength λ2 different from λ1 from the one optical terminator determined by the center node is obtained. Configure to reach the working optical interface of the center node via fiber.
Each backup route optical switch circuit of each of the n optical switch nodes receives the downstream optical packet signal of wavelength λ1 sent from the center node to the backup route optical fiber by the backup optical interface, and specific information of the downstream optical packet signal Based on the above, each backup route optical switch circuit is switched in units of optical packets so that the downstream optical packet signal on the backup route reaches one optical terminal device determined by the center node and the downstream optical packet on the backup route. By switching each backup route optical switch circuit in units of packets based on the specific information of the signal, an upstream signal having a wavelength λ2 different from λ1 from the one optical terminator determined by the center node is supplied to the backup route light. Configured to reach the standby optical interface of the center node via fiber ,
If an optical signal failure occurs at one location on the working route, the optical switch node that first detected the failure of the optical signal and all the optical switch nodes after that will use the respective working / standby switching optical switch circuits. An optical ring network device capable of maintaining communication between a center node and all optical termination devices by switching the path of an optical packet signal between the center node and each optical termination device from a working route to a backup route. The optical ring network device according to claim 1 or 2,
The working route optical switch circuit of each of the n optical switch nodes receives the downstream optical packet signal of wavelength λ1 sent from the center node to the working route optical fiber through the working optical interface, and whether or not there is an abnormality in the optical packet signal. If there is an abnormality, each active / standby switching optical switch circuit is switched so that the path of the optical packet signal is switched from the working route to the backup route. An optical ring network device that can maintain communication between the two. The optical ring network device according to claim 2 or 3,
IEEE 802.3ah defines the downstream optical packet signal of wavelength λ1 sent from the center node to the working route optical fiber by the working optical interface and the downstream optical packet signal of wavelength λ1 sent from the center node to the backup route optical fiber by the backup optical interface. As specific information of the downstream optical packet signal, LLID (Logical Link Identifier, logical link identifier) defined by IEEE 802.3ah, frame length, and control message from the center node are included. An optical ring network device configured to include. The optical ring network device according to claim 4, wherein
Each active route optical switch circuit and each backup route optical switch circuit are connected to the downstream optical packet signal in units of packets based on the LLID and frame length specified by IEEE 802.3ah, which are specific information of the downstream optical packet signal. An optical ring network device configured to switch an upstream optical packet signal in units of packets based on a control message from a center node that is specific information of switching and downstream optical packet signals. The optical ring network device according to any one of claims 1 to 5,
The working route optical switch circuit of each of the n optical switch nodes includes the first and second optical demultiplexing / multiplexing units, one optical branching unit, one optical delay circuit, and one each. First and second mx1 optical switches having m optical input / output terminals and m optical input / output terminals (m is an arbitrary number of optical termination devices connected to each optical switch node + 1), It has an optical / electrical conversion circuit, one frame analysis circuit, one downstream signal switch control circuit, one upstream signal switch control circuit, and one abnormality detection circuit,
The protection route optical switch circuit of each of the n optical switch nodes includes the first and second optical demultiplexing / multiplexing units, one optical branching unit, one optical delay circuit, and one each. First and second mx1 optical switches having one optical input / output terminal, m optical input / output terminals, one optical / electrical conversion circuit, one frame analysis circuit, and one downstream signal switch A control circuit and one upstream signal switch control circuit,
Each of the working / standby switching optical switch circuits of the n optical switch nodes includes m-1 downlink signal switching 2x1 switches, m-1 uplink signal switching 2x1 switches, and m-1 optical signals. An optical ring network device configured to have m-1 optical demultiplexers / multiplexers respectively connected to termination devices. The optical ring network device according to claim 6, wherein
In each of the working route optical switch circuits of the n optical switch nodes,
The downstream optical packet signal of wavelength λ1 on the working route optical fiber is demultiplexed by the first optical demultiplexer / multiplexer and then branched into two by the optical branching unit, and one downstream optical packet signal output is optically delayed After being delayed for a predetermined time by the circuit, it is input to the one-side terminal of the first mx1 optical switch, the other downstream optical packet signal output is converted into two electrical packet signal outputs by the optical / electrical conversion circuit, and one of the two is output. The LLID and frame length information extracted by the frame analysis circuit are input to the downlink signal switch control circuit as specific information, and the control message from the center node extracted by the frame analysis circuit is specified as specific information. The downstream optical packet signal of wavelength λ1 input to the signal switch control circuit and input to the first side terminal of the first mx1 optical switch The signal switch control circuit switches in units of optical packets based on the LLID and frame length information, and the output is switched to m-1 downstream signals of the second optical demultiplexer / multiplexer or active / backup switch circuit. It is configured to connect to one of the two side terminals of the 2x1 optical switch for use,
The upstream optical packet signal of wavelength λ2 on the working route optical fiber is demultiplexed by the second optical demultiplexer / multiplexer and then connected to one of the m-side terminals of the second mx1 optical switch, and m−1 One of the 2 side terminals of the 2 × 1 optical switch for upstream signal switching is connected to the remaining m−1 m side terminals of the second mx1 optical switch, and connected to the m m side terminals of the second mx1 optical switch. The upstream optical packet signal of wavelength λ2 is switched by the upstream signal switch control circuit in units of optical packets based on the control message from the center node, and is input to the first optical demultiplexer / multiplexer to be combined and used. Configured to transmit as an upstream optical packet signal of wavelength λ2 on the route optical fiber,
In each backup route optical switch circuit of n optical switch nodes,
The downstream optical packet signal of wavelength λ1 on the backup route optical fiber is demultiplexed by the first optical demultiplexer / multiplexer, then branched into two by the optical branching unit, and one downstream optical packet signal output is optically delayed After being delayed for a predetermined time by the circuit, it is input to the one-side terminal of the first mx1 optical switch, the other downstream optical packet signal output is converted into two electrical packet signal outputs by the optical / electrical conversion circuit, and one of the two is output. The LLID and frame length information extracted by the frame analysis circuit are input to the downlink signal switch control circuit as specific information, and the control message from the center node extracted by the frame analysis circuit is specified as specific information. The downstream optical packet signal of wavelength λ1 input to the signal switch control circuit and input to the first side terminal of the first mx1 optical switch The signal switch control circuit switches in units of optical packets based on the LLID and frame length information, and the output is switched to m-1 downstream signals of the second optical demultiplexer / multiplexer or active / backup switch circuit. It is configured to connect to one of the two side terminals of the 2x1 optical switch for use,
The upstream optical packet signal of wavelength λ2 on the working route optical fiber is demultiplexed by the second optical demultiplexer / multiplexer and then connected to one of the m-side terminals of the second mx1 optical switch, and m−1 One of the 2 side terminals of the 2 × 1 optical switch for upstream signal switching is connected to the remaining m−1 m side terminals of the second mx1 optical switch, and connected to the m m side terminals of the second mx1 optical switch. The upstream optical packet signal of wavelength λ2 is switched in units of optical packets based on the control message from the center node by the upstream signal switch control circuit, and is input to the first optical demultiplexer / multiplexer for multiplexing, Configured to transmit as an upstream optical packet signal of wavelength λ2 on the route optical fiber,
In the anomaly detection circuit of the working route optical switch circuit of each of the n optical switch nodes, the other electric packet signal output converted into the electric packet signal by the optical / electrical conversion circuit of the working route optical switch circuit is input. , When detecting that there is an abnormality in the downstream optical packet signal of wavelength λ1, two sides of the m-1 downstream signal switching 2x1 optical switch and the two sides of the m-1 upstream signal switching 2x1 optical switch By configuring each terminal connection to be switched simultaneously from the working route side to the backup route side,
If there is an abnormality in the downstream optical packet signal of wavelength λ1 received by the working route optical switch circuit of each of the n optical switch nodes, the path of the optical packet signal is switched from the working route to the backup route, and the center node and all terminals An optical ring network device that can maintain communication with the device.   8. The optical ring network apparatus according to claim 6, wherein the first and second mx1 optical switches of the working route optical switch circuit of each of the n optical switch nodes and the spare routes of each of the n optical switch nodes. An optical ring network device in which first and second mx1 optical switches of an optical switch circuit are configured by connecting 2 × 1 optical switches in a multi-stage tree shape, respectively. The optical ring network device according to any one of claims 6 to 8,
One location between the one-side terminal of the first mx1 optical switch and the first optical demultiplexer / multiplexer in the working route optical switch circuit of each of the n optical switch nodes, and the n optical switch nodes In each backup route optical switch circuit, an optical amplifier having one wavelength λ1 is provided at one location between the first side terminal of the first mx1 optical switch and the first optical demultiplexer / multiplexer,
Between the one-side terminal of the second mx1 optical switch and the first optical demultiplexer / multiplexer in the working route optical switch circuit of each of the n optical switch nodes, and the spare of each of the n optical switch nodes An optical ring network device in which one optical amplifier of each wavelength λ2 is provided between the one-side terminal of the second mx1 optical switch in the root optical switch circuit and the first optical demultiplexer / multiplexer.   10. The optical ring network device according to claim 9, wherein the first mx1 optical switch and one optical amplifier of wavelength λ1 in the working route optical switch circuit, the first mx1 optical switch and one optical amplifier in the backup route optical switch circuit. An optical amplifier of wavelength λ1, a second mx1 optical switch and one optical amplifier of wavelength λ2 in the working route optical switch circuit, a second mx1 optical switch and an optical amplifier of one wavelength λ2 in the backup route optical switch circuit, An optical ring network device in which at least one combination is configured using an element in which an mx1 optical switch and an optical amplifier are integrated.

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