KR101078055B1 - Protection recovery and switching apparatus in ring type passive optical network - Google Patents

Abstract

The present invention relates to a protective recovery switching device in an annular passive optical subscriber network. A downlink signal switch for switching the downlink signal of the optical fiber terminator according to the present invention to be transmitted to a plurality of remote nodes (RN) consisting of passive elements, and for switching uplink signals of the plurality of remote nodes to be received at the optical fiber termination device An uplink signal switch, an optical signal transceiver for transmitting and receiving an uplink signal of a plurality of remote nodes or a downlink signal of an optical path termination device, and an uplink signal of a plurality of remote nodes received through the optical signal transceiver; And a control unit configured to transmit a downlink signal switch to transmit the downlink signal to a plurality of remote nodes by bypassing the optical path of the detected section when the failure is detected by analyzing the received uplink signal. It is done. In addition, the uplink signal switch or the downlink signal switch of the optical path termination device according to the invention is characterized in that the optical switch or the electrical switch.

Annular net, protective clothing, transfer, OLT, RN

Description

Protection recovery and switching apparatus in ring type passive optical network

The present invention relates to an optical communication technology, and more particularly, to a protective recovery switching device in an annular passive optical subscriber network.

The present invention is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Communication Research and Development. [Task management number: 2007-S-014-02, Project name: Metro-access all-optical integrated network technology Development].

Conventional annular network protection and recovery devices typically require network recovery within a minimum recovery time of 50ms in a SDH (Synchronous Digital Hierarchy) / SONET (Synchronous Optical Network) system. However, when the size of the annular network is relatively large and there are many transmission network elements, it is difficult to guarantee a minimum recovery time of 50 ms. As such, it is difficult to guarantee the minimum recovery time of 50 ms because the determination of the availability of the annular network line is higher than the physical layer. In addition, the conventional annular network protection recovery device has to perform communication between each node (OLT, Node) in order to know the available line, the problem that the protection recovery time exceeds the reference time.

In addition, in the conventional annular passive optical subscriber network, protection recovery and protection switching were performed using a failure detector and an optical switch as active elements in a remote node (RN) for protection recovery and protection switching. The use of such fault detectors and optical switches in remote nodes is beyond the meaning of passive optical subscriber networks. In addition, although the optical switch used in the conventional annular passive optical subscriber network can satisfy the switching time sufficiently, the switching time is slower than the electric switch, and there is a problem in that the installation cost is high.

In the event of a failure in the passive optical subscriber network, the purpose is to solve the problem quickly so as to facilitate the network function.

Furthermore, an object of the present invention is to control all functions for protective recovery in a fiber termination device and to configure a remote node as a passive element.

Furthermore, the present invention aims to replace the optical switch with an electrical switch to reduce the loss of the entire optical link, to reduce the speed of protection transfer, and to reduce the manufacturing cost.

The foregoing technical problem is achieved by the characteristic aspects of the present invention described below. A downlink signal switch for switching the downlink signal of the optical fiber termination device to be transmitted to a plurality of remote nodes (RN) consisting of passive elements only, and for switching the uplink signals of the plurality of remote nodes to be received by the optical fiber termination device An uplink signal switch, an optical signal transceiver for transmitting and receiving an uplink signal of a plurality of remote nodes or a downlink signal of an optical path termination device, and an uplink signal of a plurality of remote nodes received through the optical signal transceiver; And a control unit configured to transmit a downlink signal switch to transmit the downlink signal to a plurality of remote nodes by bypassing the optical path of the detected section when the failure is detected by analyzing the received uplink signal. It is done.

An optical fiber termination device and a plurality of remote nodes in accordance with an additional aspect of the present invention are characterized in that they communicate bi-directionally or unidirectionally via one or a plurality of optical paths.

The uplink signal switch or the downlink signal switch according to an additional aspect of the present invention is an optical switch or an electrical switch, and can control optical paths of a plurality of remote nodes, and can improve signal quality and protection recovery performance.

The control unit according to an additional aspect of the present invention includes a failure detection unit for determining whether a failure by analyzing the uplink signals of the plurality of remote nodes received, and a switch switching unit for switching the downlink signal switch or the uplink signal switch according to the determination of the failure. Characterized in that.

The failure detection unit according to an additional aspect of the present invention is characterized in that it comprises a failure section acquisition unit for extracting which light beam section a failure occurs through the analysis of the received signal of the plurality of remote nodes.

As described above, the present invention proposes a protective recovery switching device in an annular passive optical subscriber network. In other words, the protection layer and the transfer operation of the annular network previously performed on the physical layer may be performed in the physical layer, and a plurality of remote nodes RN may be configured as passive elements. In addition, by implementing the optical switch of the optical fiber termination unit stage to the electrical switch for the path of the protective recovery can improve the protective recovery performance and signal quality, it is possible to reduce the installation cost.

The foregoing and further aspects of the present invention will become more apparent through the preferred embodiments described with reference to the accompanying drawings. Hereinafter, the present invention will be described in detail so that those skilled in the art can easily understand and reproduce the present invention through these embodiments.

FIG. 1A is an exemplary diagram showing an annular optical subscriber network with one optical path according to an embodiment of the present invention, and FIG. 1B is a diagram illustrating an annular optical subscriber network with two optical paths according to an embodiment of the present invention. It is an illustration.

As shown, the annular optical subscriber network of FIG. 1A has an optical line termination (OLT) 100 and remote nodes 1,2,3,4 (referred to as RN) ( 400 is connected in a circle through a single light path. Here, the plurality of RN 400 connected in a circular manner through the optical line termination device 100 and a single optical path is composed of a passive element. The OLT 100 of such an annular optical subscriber network communicates bidirectionally with a plurality of RNs 400 through one optical path. That is, the OLT 100 transmits the downlink signal to the plurality of RNs 400 in the forward or reverse direction, and the plurality of RNs 400 transmits the uplink signal to the OLT 100 in both directions. Accordingly, the OLT 100 may receive the same uplink signals of the plurality of RNs 400 through the forward or reverse optical paths, and detect the uplink signals of the RNs 400 received in both directions to detect A, B, and C. It is possible to know which of the sections, D, and E, have a failure, that is, a short circuit. When the shorted optical path is detected, the OLT 100 transmits the downlink signal in the forward and reverse directions so that all the RNs 400 can receive the downlink signal. On the other hand, since the plurality of RN 400 transmits the uplink signal in both directions to transmit to the OLT 100, even if the optical path of any of the A, B, C, D, E section is short-circuited, the OLT 100 is RN ( 400 may receive an uplink signal.

In the annular optical subscriber network of FIG. 1B, the OLT 100 and the RN1, 2, 3, 4 (400) are circularly connected through two optical paths. Here, the optical line termination device 100 and the plurality of RNs 400 connected in a circular manner through two optical lines are preferably configured as passive elements. The OLT 100 of such an annular optical subscriber network communicates unidirectionally with a plurality of RNs 400 through two optical paths. In the same manner as in FIG. 1A, the OLT 100 transmits a downlink signal to the RNs 400 on one side of the forward optical path a or the other side of the reverse optical path b. The uplink signal to be transmitted is distributed to the OLT 400, and the uplink signal distributed through the one optical path a and the other optical path b is transmitted to the OLT 400.

Accordingly, the OLT 100 may receive the uplink signals of the plurality of RNs 400 through one light beam a and the other light beam b, and the one light beam a and the other light beam b. By detecting the upstream signals of the RN (400) received through the) it can be seen which of the A, B, C, D, E of the optical path section of the path, that is, the short circuit. When the shorted optical path section is detected, the OLT 100 transmits a downlink signal through one optical path (a) and the other optical path (b) so that all RNs 400 can receive the downlink signal. On the other hand, since the RN 400 distributes the uplink signal transmitted to the OLT 100 and transmits the distributed uplink signal to the OLT 100 through one optical path (a) and the other optical path (b) A, The OLT 100 may receive an uplink signal from the RNs 400 even if the optical paths of any of the B, C, D, and E sections are shorted. Hereinafter, a passive protection recovery switching device for smooth data communication between the OLT 100 and the plurality of RNs 400 in the annular passive optical subscriber network will be described in detail.

Figure 2 is a block diagram showing a passive protective recovery switching device in the annular passive optical subscriber network according to an embodiment of the present invention.

As illustrated, the passive protection recovery switching device 200 includes an optical signal transceiver 210, a downlink signal switch 220, an uplink signal switch 230, and a controller 240.

The optical signal transceiver 210 receives a down signal of the OLT 100 or an up signal of the plurality of RNs 400. The downlink signal switch 220 switches so that a plurality of downlink signals of the OLT 100 are transmitted to the RNs 400, and the uplink signal switch 230 transmits uplink signals of the plurality of RNs 400 to the OLT 100. Switch to receive. The downlink signal switch 220 and the uplink signal switch 230 is composed of an electrical switch or an optical switch that performs an operation by an electrical signal to control the optical path of the plurality of RN (400), signal quality and protection recovery It can improve performance.

The controller 240 transmits the uplink signals of the plurality of RNs 400 received through the optical signal transceiver 210 to the OLT 100 through the uplink signal switch 230, and when a failure is detected, the failure is detected. The downlink signal switch 220 is operated so that downlink signals are transmitted to the plurality of RNs 400 by bypassing the low section. Such a control unit 240 may be achieved through the failure detection unit 241 and the switch switching unit 245. The failure detection unit 241 analyzes the received up signals of the plurality of RNs 400 to determine whether there is a failure, and the switch switching unit 245 determines the failure of the failure detection unit 241 to determine the downlink signal 220. ) Or up signal switch 230. That is, the switch switching unit 245 switches the uplink signal switch 230 so that the uplink signals of the plurality of RNs 400 are transmitted to the OLT 100, or the downlink signals of the OLT 100 are the plurality of RNs 400. To switch the downlink signal switch 220 to be transmitted to them. Meanwhile, the failure detection unit 241 analyzes uplink signals of the plurality of RNs 400 through the failure location acquisition unit 243 to extract which path section a failure occurs in the optical path section where the failure is detected by the OLT 100. Tells. Meanwhile, the OLT 100 and the plurality of RNs 400 according to an additional aspect of the present invention preferably transmit and receive up / down signals in both directions or in one direction through one or a plurality of optical paths.

According to an embodiment, as shown in FIG. 1A, when the annular subscriber network performs data communication in one direction through one optical path, the OLT 100 may have normal optical path sections A, B, C, D, and E. In this case, the downlink signal is transmitted to the RN1, 2, 3, 4 (400) connected to the respective optical path sections in the forward or reverse direction. That is, if the downlink signal switch is connected to transmit the downlink signal in the forward direction, the downlink signal of the OLT 100 is transmitted in the order of RN1, 2, 3, 4 (400) through the optical signal transceiver 210, and the reverse direction When the downlink signal switch is connected to transmit the downlink signal, the downlink signal of the OLT 100 is transmitted in the order of RN4, 3, 2, 1 (400) through the optical signal transceiver 210. Here, the downlink signal switch can control the signal path and all the light paths by the electrical switch, it is possible to improve the signal quality and protection performance. However, it is preferable that the down signal switch according to the present invention can be composed of not only an electric switch but also an optical switch.

The downlink signals transmitted to the RNs 400 through the optical signal transceiver 210 are transmitted to the RNs 400 on the inherent wavelength band through the wavelength multiplexer 300. Accordingly, the plurality of RNs 400 receive the downlink signal of the OLT 100 as shown in FIG. 3A.

3A is a block diagram illustrating an RN connected to one optical path according to an embodiment of the present invention to transmit and receive an up or down signal with an OLT.

As shown, the downlink signal of the OLT 100 carried in the native wavelength band through the wavelength multiplexer 300 is transmitted through a predetermined forward or reverse optical path. When received by the plurality of RNs 400 through a predetermined forward or reverse optical path, each of the RNs 400 filters the downlink signal transmitted to it through the optical filter 411. Thereafter, each of the RNs 400 receives the downlink signal from the optical filter 411 by using the splitter combiner 410. Accordingly, each RN 400 receives the downlink signal of the OLT 100 transmitted in the forward or reverse optical path. Meanwhile, the RNs 400 receiving the downlink signal transmit the uplink signal to the OLT 100 using their distribution combiner 410. That is, the RN 400 equally distributes the uplink signal to be transmitted to the OLT 100 through the distribution combiner 410. Thereafter, the distribution combiner 410 loads the distributed uplink signal in the band allocated to the child using the optical filter 411 and transmits the uplink signal to the OLT 100 through the reverse optical path and the forward optical path. As such, the splitting combiner 410 that receives the downlink signal and distributes the uplink signal is used simultaneously as the splitter and the combiner according to the direction of using one element in the bidirectional direction of the optical passive element.

As such, when the uplink signals of the RNs 400 are received in both directions, the wavelength multiplexer 300 obtains the uplink signals of the respective RNs 400 for each wavelength band. When the uplink signals of the RNs 400 obtained from the wavelength multiplexer 300 are received by the optical signal transceiver 210, the failure detector 241 checks the uplink signals of the received RNs 400 and receives them in both directions. Detect whether or not That is, if there are no obstacles in the optical path sections A, B, C, D, and E, the optical signal transceiver 210 receives all the uplink signals of the RNs 400 transmitted in the forward and reverse optical paths. Accordingly, the failure detector 241 determines that the respective optical path sections are normally connected. Thereafter, the switch switching unit 245 switches the uplink signal switch 230 so that the uplink signals of the RNs 400 received in the forward and reverse directions are transmitted to the OLT 100. Accordingly, the OLT 100 receives the uplink signals transmitted by the RNs 400 in the forward and reverse directions. Here, the uplink signal switch 230 may control all the light path sections by the electric switch. However, it is preferable that the uplink signal switch according to the present invention can be composed of not only an electric switch but also an optical switch.

On the other hand, if it is detected that the uplink signal received by the optical signal transceiver 210 through the failure detector 241 is transmitted only through the optical path in either the forward direction or the reverse direction, the failure position acquisition unit 243 is the optical path section Check which line of A, B, C, D, or E has a failure. For example, the optical signal transceiver 210 receives the uplink signals of the RN1 400 and the RN2 400 through the reverse optical path, and the uplink signals of the RN3 400 and the RN4 400 through the forward optical path. When receiving the error, the failure detection unit 241 determines that the same uplink signals of the RN 400 are not received through the two-way optical path, detects that a failure has occurred, and through the failure position acquisition unit 243 Ask to see if the section is shorted. That is, as described above, since the RN 400 transmits the same uplink signal to the OLT 100 through the two-way optical path, when a failure occurs in each optical path section, the uplink signals of the RN 400 are forward or backward. It is received only through the optical path in either direction.

Accordingly, the failure location acquisition unit 243 analyzes the upstream signals of the received RNs 400 and checks that a failure, that is, a short circuit, is performed in the optical path section C. FIG. As such, when the path of the optical path having a failure is confirmed through the obstacle location acquisition unit 243, the failure detection unit 241 transmits failure detection information indicating that a failure has occurred in the optical path section C to the OLT 100. In addition, the failure detection unit 241 transmits the failure detection information to the switch switching unit 245, accordingly, the switch switching unit 245 is upstream of the RN1 (400) and RN2 (400) received through the reverse optical path The uplink signal switch 230 is switched so that the uplink signals of the RN3 400 and the RN4 400 received through the signal and the forward optical path are transmitted to the OLT 100. In addition, the switch switching unit 245 controls the downlink signal switch 220 set to transmit the downlink signal in the forward or reverse direction as the failure detection information is received from the failure detection unit 241, so that the downturn of the OLT 100 is performed. The signal is sent to all RNs 400 by bypassing the optical path of the shorted section. That is, when the downlink signal is transmitted from the OLT 100, the switch converter 245 converts the downlink signal switch with reference to the failure detection information received from the failure detection unit 241, and accordingly, the downlink of the OLT 100. The signal is sent to all RNs 400 through the forward and reverse optical paths.

 According to another embodiment, when the annular subscriber network performs data communication in one direction through two optical beams as shown in FIG. 1B, the OLT 100 may determine that each optical fiber segment A, B, C, D, or E has been divided. Normally, the downlink signal is transmitted to the RN1, 2, 3, 4 (400) connected to the respective optical path sections in one direction (a) or the other direction (b). That is, when the downlink signal switch is connected to transmit the downlink signal in one direction (a), the downlink signal of the OLT 100 is in the order of RN1, 2, 3, 4 (400) through the optical signal transceiver 210. When the downlink signal switch is connected to transmit the downlink signal in the other direction (b), the downlink signal of the OLT 100 is in the order of RN4, 3, 2, 1 (400) through the optical signal transceiver 210. Is sent to. Here, the down signal switch is a switch implemented as an electric switch, and such a down signal switch may control all the light beam sections. However, it is preferable that the down signal switch according to the present invention can be composed of not only an electric switch but also an optical switch. The downlink signals transmitted to the RNs 400 through the optical signal transceiver 210 are transmitted to the RNs 400 on the inherent wavelength band through the wavelength multiplexer 300. Accordingly, the plurality of RNs 400 receive the downlink signal of the OLT 100. Meanwhile, the RNs 400 receiving the downlink signal transmit the uplink signal to the OLT 100 as shown in FIG. 3B.

3B is a block diagram illustrating an RN connected to two optical paths according to an embodiment of the present invention to transmit and receive an up or down signal with an OLT.

As shown, the downlink signal of the OLT 100 loaded in the intrinsic wavelength band through the wavelength multiplexer 300 is transmitted through an optical path in one predetermined direction (a) or the other direction (b). When the plurality of RNs 400 are received through the predetermined one direction (a) or the other direction (b) optical path, each of the RN 400 is an optical filter connected to one side (a) or the other direction (b) The downlink signal transmitted to itself through the device 421 is filtered. Thereafter, each of the RNs 400 receives the downlink signal filtered by the optical filter 421 using the splitter combiner 420. Accordingly, each of the RNs 400 receives the downlink signal of the OLT 100 transmitted in the optical path in one direction (a) or the other direction (b). Meanwhile, the RNs 400 receiving the downlink signal transmit the uplink signal to the OLT 100 using their distribution combiner 430. That is, the RN 400 equally distributes the uplink signal to be transmitted to the OLT 100 through the distribution combiner 430. Thereafter, the distribution combiner 430 loads the distributed uplink signal in the band allocated to the child using the optical filter 431, and through the optical path in one direction (a) and the optical path in the other direction (b). Transmit to the OLT 100 side.

As such, the distribution combiners 420 and 430 that receive the downlink signal and distribute the uplink signal are simultaneously used as the divider and the combiner according to the direction of using one element in the bidirectional direction of the optical passive element. When the upstream signals of the RN 400 are received to the OLT 100 through the optical path in one direction (a) and the other direction (b), the wavelength multiplexer 300 receives each RN 400 received for each wavelength band. Acquire an up signal of these. When the uplink signals of the RNs 400 obtained from the wavelength multiplexer 300 are received by the optical signal transceiver 210, the failure detector 241 checks the uplink signals of the received RNs 400 in one direction (a). And (b) it is detected whether or not it is received through the optical path in the other direction (b).

  That is, if there are no obstacles in the optical path sections A, B, C, D, and E, the optical signal transceiver 210 transmits the uplink signals of the RNs 400 transmitted to the optical path in one direction (a) and the other direction (b). Receive all Accordingly, the failure detector 241 determines that the respective optical path sections are normally connected. Thereafter, the switch switching unit 245 switches the uplink signal switch 230 so that the uplink signals of the RNs 400 received from the optical paths in one direction (a) and the other direction (b) are transmitted to the OLT 100. Accordingly, the OLT 100 receives the uplink signals of the RNs 400 transmitted from the optical paths in one direction (a) and the other direction (b). Here, the uplink signal switch 230 is implemented as an electrical switch, and can control all the light path sections. However, it is preferable that the uplink signal switch according to the present invention can be composed of not only an electric switch but also an optical switch.

On the other hand, if it is detected that the uplink signal received by the optical signal transmission and reception unit 210 through the failure detection unit 241 is transmitted only through the optical path in any one direction (a) and the other direction (b), the failure position acquisition The unit 243 checks which of the light beam sections A, B, C, D, and E has a failure. For example, the optical signal transceiver 210 receives the uplink signals of the RN1 400 and the RN2 400 through the optical path in the other direction (b), and the RN3 (400) through the optical path in the one direction (b). ) And the uplink signal of the RN4 400, the failure detection unit 241 determines that the same uplink signal of the RN 400 is not received through a bidirectional optical path, detects that a failure has occurred, and acquires a failure location. The unit 243 requests to identify which light beam section is shorted. Accordingly, the failure location acquisition unit 243 analyzes the upstream signals of the received RNs 400 and checks that a failure, that is, a short circuit, is performed in the optical path section C. FIG. As such, when the path of the optical path having a failure is confirmed through the obstacle location acquisition unit 243, the failure detection unit 241 transmits failure detection information indicating that a failure has occurred in the optical path section C to the OLT 100. In addition, the failure detection unit 241 transmits the failure detection information to the switch switching unit 245, accordingly, the switch switching unit 245 is the RN1 (400) and RN2 (received through the optical path in the other direction (b) ( The uplink signal switch 230 is switched so that the uplink signals of the RN3 400 and the RN4 400 received through the uplink signal of the signal 400 and the one-way direction b are transmitted to the OLT 100. In addition, the switch switching unit 245 is a predetermined downlink signal switch 220 so that the downlink signal is transmitted through the optical path in one direction (a) or the other direction (b) as the failure detection information is received from the failure detection unit 241. ) So that the downlink signal of the OLT 100 bypasses the optical path of the shorted section and is transmitted to all the RNs 400. That is, when the downlink signal is transmitted from the OLT 100, the switch converter 245 converts the downlink signal switch with reference to the failure detection information received from the failure detection unit 241, and accordingly, the downlink of the OLT 100. The signal is transmitted to all RNs 400 through the optical path in one direction (a) and the other direction (b).

So far I looked at the center of the preferred embodiment for the present invention.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1A is an exemplary view showing an annular optical subscriber network having one optical path according to an embodiment of the present invention;

1B is an exemplary view showing an annular optical subscriber network having two optical paths according to an embodiment of the present invention;

Figure 2 is a block diagram showing a passive protection recovery switching device in the annular passive optical subscriber network according to an embodiment of the present invention,

3A is a block diagram illustrating an RN connected to one optical path according to an embodiment of the present invention and transmitting and receiving an up or down signal with an OLT;

3B is a block diagram illustrating an RN connected to two optical paths according to an embodiment of the present invention for transmitting and receiving an up or down signal with an OLT.

<Explanation of symbols for the main parts of the drawings>

100: OLT 200: Manual Protective Recovery Switching Device

210: optical signal transceiver 220: downlink signal switch

230: upward signal switch 240: control unit

241: failure detection unit 243: failure location acquisition unit

245 switch switching unit 300 wavelength multiplexer

400: RN 410, 420, 430: distribution combiner

411, 421, 431: Optical Filter

Claims (6)

A downlink signal switch for switching the downlink signal of the optical path termination device to be transmitted to a plurality of remote nodes (RN); An uplink signal switch for switching uplink signals of the plurality of remote nodes to be received by the optical fiber termination device; An optical signal transmitting / receiving unit configured to transmit and receive a downlink signal of the optical fiber termination device or uplink signals of the plurality of remote nodes; The uplink signals of the plurality of remote nodes received through the optical signal transmission and reception unit are transmitted to the optical fiber termination device through the uplink signal switch, and if the fault is detected by analyzing the received uplink signal, the fault is detected. A controller configured to operate the downlink signal switch to bypass the optical path so that downlink signals are transmitted to the plurality of remote nodes; Including; And a plurality of remote nodes are configured as passive elements. delete The method of claim 1, And the plurality of remote nodes communicate with each other in one or a plurality of optical paths in one or more optical paths. The method of claim 1, The uplink signal switch or the downlink signal switch is An electrical switch or an optical switch, the protective recovery switching device in an annular passive optical subscriber network, characterized in that for controlling the optical path of the plurality of remote nodes. The method of claim 1, wherein the control unit: A failure detection unit that analyzes the received uplink signals of the plurality of remote nodes to determine whether a failure occurs; A switch switching unit for switching the down signal switch or the up signal switch according to the failure determination; Protective recovery switching device in the annular passive optical subscriber network comprising a. The method of claim 4, wherein the failure detection unit: A failure section acquisition unit for extracting which path section a failure occurs through analysis of the received uplink signals of the plurality of remote nodes; Protective recovery switching device in the annular passive optical subscriber network comprising a.

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