KR100575988B1 - Method for ONU Activation in Gigabit-capable PON - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a Gigabit-capable Passive Optical Network (hereinafter referred to as "GPON").

2. The technical problem to be solved by the invention

In order to prevent a case in which a request signal and a window signal are mistaken as signals of different processes in the GPON, an identification field for distinguishing a request frame and a window frame for each process is provided. Its purpose is to create a GTC control frame that adds and to register the ONU in a gigabit passive optical subscriber network using it.

3. Summary of the Solution of the Invention

The present invention relates to a method for registering an ONU (Optical Network Unit) in a Gigabit-capable Passive Optical Network (hereinafter referred to as "GPON"), wherein the Optical Line Termination (OLT) is set by the ONU. A first step of indicating that the process is one of the processes for registration and generating a request frame including a request field for identifying each process and delivering the request frame to an ONU to be registered; And a second step of performing, by the ONU receiving the request frame, generating and delivering a Window frame indicating that the request frame is a response to the request frame.

4. Important uses of the invention

The present invention is used in GPON and the like.

Request, Window, ONU Registration, GPON

Description

Registration method for ONU in Gigabit passive optical subscriber network {Method for ONU Activation in Gigabit-capable PON}             

1 is an embodiment configuration diagram showing an example of a conventional PON.

2 shows a protocol stack structure of a typical GPON.

3 is a structural diagram of an embodiment of a general downlink GTC frame.

4 is a structural diagram of an embodiment of a general uplink GTC frame.

5 is a flow diagram of an embodiment of a power leveling procedure in a conventional GPON.

6 is a flowchart illustrating an embodiment of a serial number process in a conventional GPON.

7 is a flow diagram of an embodiment of a ranging procedure in a conventional GPON.

8 is a structure diagram of an embodiment of a control frame for indicating that a request frame is using a hold field in a method for registering an ONU in a GPON according to the present invention;

9 is a structural diagram of a second embodiment of a control frame for indicating that a request frame is using a hold field in a method for registering an ONU in a GPON according to the present invention;

10 is a structural diagram of a third embodiment of a control frame for indicating that a request frame is using a hold field in a method for registering an ONU in a GPON according to the present invention;

FIG. 11 is a diagram illustrating an embodiment of a control frame for indicating that a request frame is indicated by using an ONU_ID field in a method for registering an ONU in a GPON according to the present invention; FIG.

12 is a structural diagram of an embodiment of a control frame for indicating that the window frame in the method for registering ONU in GPON according to the present invention.

FIG. 13 is a diagram illustrating a structure of a control frame for indicating that a window frame is displayed using an ONU_ID field in a method for registering an ONU in a GPON according to the present invention; FIG.

The present invention relates to a Gigabit-capable Passive Optical Network (hereinafter referred to as "GPON").

Recently, various network structures and evolutionary measures have been proposed for constructing subscriber networks from telephone stations to buildings and homes. Examples include x-Digital Subscriber Line (xDSL), Hybrid Fiber Coax (HFC), Fiber To The Building (FTTB), Fiber To The Curb (FTTC), and Fiber To The Home (FTTH). Among these, FTTx (x = B, C, H) may be classified into an active FTTx implemented by an active optical network (hereinafter referred to as an “AON”) configuration and a passive FTTx implemented by a PON configuration. have.

At this time, the PON involved in the implementation of the passive FTTx has a point-to-multipoint topology made by passive devices, and thus, is an economical optical subscriber network implementation plan in the future. Is being presented. In other words, the PON is a 1 × N passive optical splitter (one optical line termination) and a plurality of optical network units (hereinafter referred to as “ONUs”). Optical Distribution Network (hereinafter referred to as " ODN ") to form a distributed topology of a tree structure.

In the form of such a PON, an Asynchronous Transfer Mode Passive Optical Network (hereinafter referred to as “ATM-PON”) was first developed and standardized. The standardization content is ITU-T (International). It is described in ITU-T G.982, ITU-T G.983.1, and ITU-T G.983.3, documented in the Telecommunication Union-Telecommunication section, and GPON standardization is currently underway in ITU-T.

1 is a diagram illustrating an exemplary embodiment of a conventional PON. Typically, a PON includes one OLT and a plurality of ONUs. In the example of FIG. 1, three ONUs 12a, 12b, and 12c are connected to one OLT 10 through an ODN 16. It was.

Referring to FIG. 1, the OLT 10 is located at the root of a tree structure and plays a central role for providing information to each subscriber of an access network. An ODN 16 is connected to the OLT 10. The ODN 16 has a tree topology structure and transmits downstream data frames transmitted from the OLT 10 to the ONUs 12a, 12b,. 12c), and reversely multiplexes upstream data frames from the ONUs 12a, 12b, and 12c and transmits them to the OLT 10. On the other hand, the ONUs 12a, 12b, and 12c receive the downlink data frame, provide it to the end users 14a, 14b, and 14c, and output data from the end users 14a, 14b, and 14c as an uplink data frame. Transmit to OLT 20 via ODN 16. In this case, the end users 14a, 14b, and 14c connected to the respective ONUs 12a, 12b, and 12c, respectively, represent various types of subscriber network terminators that can be used in a PON including a network terminal (NT). do.

In general, ATM-PON transmits up / down ATM cells having a size of 53 bytes in the form of data frames that are bundled in a certain size. In the PON structure of the tree type as shown in FIG. The down cells to be distributed to each of the ONUs 12a, 12b, 12c will be inserted properly. In addition, in the case of uplink transmission, the OLT 10 accesses data transmitted from the ONUs 12a, 12b, and 12c in a time division multiplexing (TDM) manner. At this time, since the ODN 16 connected between the OLT 10 and the ONUs 12a, 12b, and 12c is a passive element, the OLT 10 is a passive element using a virtual distance correction algorithm called ranging. The ODN 16 prevents data from colliding. In addition, during downlink data transmission from the OLT 10 to the ONUs 12a, 12b, and 12c, the OLT 10 and the ONUs 12a, 12b, and 12c are mutually encrypted and maintained for encryption to ensure confidentiality. It is designed to send and receive OAM (Operations, Administration and Maintenance) messages for maintenance. To this end, up / down frames have corresponding data fields in dedicated ATM cells or general ATM cells that can send and receive messages at regular intervals.

Unlike the broadband passive optical network (hereinafter referred to as "BPON") based on the standardized G.983 series operating as described above, GPON is a cell that processes ATM services. In addition to the basic transmission method (aka ATM mode), the GEM (GPON Encapsulation Method) method (aka GEM mode) that handles variable length packets such as time division multiplex (TDM) and Ethernet (Ethernet) services simultaneously Support. In this case, the ATM mode maps and transmits the transmission data to the GTC frame on a cell basis, and the GEM mode maps the transmission data to the GTC frame on each GEM frame basis.

2 illustrates a protocol stack structure of a typical GPON. Referring to FIG. 2, a protocol stack of a GPON includes a protocol layer 100 interfacing with a higher layer, a GTC layer 200, and a GPON physical media dependent (GPM) layer 300, and a protocol layer 100. ) Includes an Asynchronous Transfer Mode (ATM) client 110, an ONT Management Control Interface (OMCI) 120, a GEM client 130, and a Physical Layer Operation Administration Maintenance (PLOAM) 140 module.

The GPON protocol having such a configuration multiplexes the upper frame to the GTC frame in the GTC layer 200, and among these, the ATM client 110 supports the ATM mode transmission method, and the GEM client 130 the GEM It supports mode transmission method.

The ATM client 110 maps the transmission data to the GTC frame in fixed length cells in the ATM mode. In this case, if there is a space shorter than the cell length (usually 53 bytes) in the GTC frame, the transmitted data is mapped to the next frame and transmitted. Therefore, in case of ATM mode, there is no case of splitting cells.

However, since the GEM frame is a variable length packet, when the GEM client 130 maps the GEM frame to the GTC frame, the GEM frame 130 may divide and transmit the GEM frame to efficiently use the bandwidth.

For example, when the GEM client 130 receives user data from a higher layer, the GEM client 130 may determine the spatial information (eg, length) of the GTC frame currently waiting from the GTC layer 200. Based on the information, the current user data is divided into multiple GEM frames or one GEM frame without division, and then the GEM frame is transmitted to the GTC layer. Then, the GTC layer 200 maps the GEM frame to the currently waiting GTC frame and transmits it.

On the other hand, the receiving side reassembles the GEM frame thus divided in the GEM layer 20 and delivers to the higher layer.

3 is a structural diagram of an embodiment of a general downlink GTC frame.

First, the GTC frame is generally composed of a physical control block downstream (PCBd) part 31 and a payload part 32, and each GTC frame has a length of 125us.

Here, the payload portion 32 is composed of data of the ATM portion and the GEM portion. In addition, the PCBd part 31 serving as a header is composed of 4 bytes of general synchronization (PSync) field 301 for synchronization, and 2 bytes of FEC use state for indication of a long frame. And an Ident field 302 indicating a state of key-switching, a Physical Layer OAM downstream (PLOAMd) field 303, and bit-interleaved parity used for estimating a bit error rate. Bit Interleaved Parity (BIP) 304 indicating parity, Plend (Payload length) 305 indicating the length of the ATM portion of the payload, and 4 bytes, the length of the GEM portion of the payload. It is subdivided into Plend (Payload length) 306 indicating a and a US BW map field 307 containing bandwidth allocation information for uplink traffic.

Here, the Ident field 302 includes a Key Indic field 308 indicating a state of key-switching, a FEC Indic field 309 indicating a state of FEC use, and a 6-bit reserved field 310. ) And a multiframe counter field 311 indicating the number of frames of the multiframe.

The US BW map field 307 is composed of several N sets of 8 bytes, each set containing allocation bandwidth information for one "Alloc_ID". That is, when each set is called an access, the US BW map field 307 is composed of accesses of access 1 307-1 to access N 307-N, each access being 12 bits. Alloc_ID field 312 is configured to indicate the ID of the ONU bandwidth allocated to the OLT, 4 bits flag (Flags) field 313 indicating information about the upstream transmission of the PHY overhead, 2 bytes Sstart field 314 indicating the start time of the upstream transmission window, Sstop field 315 consisting of two bytes to indicate the end time of the upstream transmission window, Reserved field consisting of 1 byte 316, bandwidth And a CRC field 317 for error correction of the allocation structure. Here, the flag field 313 indicating information on the upstream transmission of the PHY overhead indicates information on whether the PLSu (Power Leveling Sequence), PLOAMu, PCBu is included in the upstream frame to be sent, whether FEC is used, and the like. .

4 is a structural diagram of an embodiment of a general uplink GTC frame.

First, the uplink GTC frame is composed of a physical layer overhead (PLOu) field 41, a power leveling sequence upstream (PLSu) field 42, a PLOAMu field 43, a PCBu field 44, and a payload portion 45. do. Here, each of the headers except for the payload portion 45 may be included in the frame as determined in the flag field 313 of the downlink frame.

The PLOu field 41 is composed of a preamble field 401 and a delimiter field 402, 1 byte for amplification, phase recovery, and frame synchronization, and is used for estimating a bit error rate. A BIP field 403 indicating an interleaved parity, an ONU-ID field 404, and an Ind field 405 for providing an OLT status to the OLT.

The PLOAMu field 43 is composed of a PON ID field 406, which is a value shown in G.983.1, an Msg ID field 407 indicating a PLOAM message type, a Message field 408, and a CRC field 409.

The PCBu field 44 is composed of a DBA field 410 and a CRC field 411 containing queue information of the T-CONT.

In general, in order to initialize the ONU, a power leveling process, a serial number process, and a ranging process, which is a virtual distance correction algorithm, are performed.

A flowchart of performing such an initialization process using the up and down structures of the GTC frame shown in FIGS. 3 to 4 will be described below with reference to FIGS. 5 to 7.

5 is a flowchart illustrating an embodiment of a power leveling process in a conventional GPON.

First, if there is an ONU 51 in the operating state 501 in the OLT 52 and the new ONU 53 is in the Power Setup State 502, then the OLT 52 is in the operating state. After stopping the ONUs 51 for a predetermined time (503, 504), waiting for a ranging delay (Ranging Delay), and transmits the Power_Setup_Request to the ONU 53 to set the power (505).

Upon receiving the Power_Setup_Request, the ONU 53 transmits a Power_Setup_Window after a delay of a random delay (506), generates a power setup success event (507), and proceeds to a serial number process (508).

6 is a flowchart illustrating an embodiment of a serial number process in a conventional GPON.

First, if there is an ONU 51 in the operating state 601 in the OLT 52 and the new ONU 53 is in the Serial Number State 602, then the OLT 52 is in the operating state. After stopping the ONUs 51 for a predetermined time (603, 604), waiting for a ranging delay, and sending a Serial_Number_Request to the ONU 53 to perform a serial number operation (605).

After receiving the Serial_Number_Request, the ONU 53 transmits the Serial_Number_Window after delaying by a random delay (606), receives the ONU_ID message (Assign ONU_ID) 607, and proceeds to the ranging process (608). .

7 is a flowchart illustrating an exemplary ranging process in a conventional GPON.

First, if there is an ONU 51 in the operating state 701 in the OLT 52 and a new ONU 53 is in the ranging state 702, then the OLT 52 is in the operating state. After stopping the ONUs (703, 704) for a predetermined time, waiting for a ranging delay (Ranging Delay), and sends a Ranging_Request to the ONU 53 to be ranging (705).

Upon receiving the Ranging_Request, the ONU 53 transmits the Ranging_Window (706). If the operation 705 and 706 are repeated again and the OLT 52 sends a Ranging-Time message to the ONT (707), the ONU 53 receives the message and proceeds to the operation state (708).

The control frames Power_Setup_Request, Power_Setup_Window, Serial_Number_Request, Serial_Number_Window, Ranging_Request and Ranging_Window presented in the draft of the GPON for the operation of FIGS. 5 to 7 are as shown in FIGS. 5 to 7. In other words, it can be seen that the general control frame does not include the payload portion and is based on the GTC frame format shown in FIGS. 3 and 4.

Referring to the example of Power_Setup_Request and Power_Setup_Window shown in FIG. 5, the Power_Setup_Request is composed of an ONU_ID field 521 indicating an ID of the ONU of the PCBd 31 and a 4-bit flag indicating information on upstream transmission of PHY overhead. Field 522, consisting of two bytes, a Start field 523 that indicates the start time of the upstream transmission window, and consisting of two bytes, a Stop field 524 that indicates the end time of the upstream transmission window, ONU The ONU_ID is assigned to "254" to indicate the registration process, the PLSu value is registered among the values of the flag field 522, the Start field 523 is "0", and the Stop field 524 is the length of the power setting field. The value is set to (Power Setup Field Length). In this case, assigning ONU_ID to "254" indicates that the control frame is for registration of the ONU.

The Power_Setup_Window consists of an ONU_ID field 525 indicating the ID of the ONU of the PLOu 41 and a PLSu field 42 indicating the power setting field.

As shown in Figs. 6 to 7, Serial_Number_Request, Serial_Number_Window, Ranging_Request, and Ranging_Window also have a structure similar to the above frame structure.

Accordingly, it can be seen that the overall configuration is similar in view of the request and window control frame formats presented in the draft of the GPON shown in FIGS. 5 to 7. In addition, it can be seen that there is no identification field for distinguishing each process. Accordingly, there is a problem in that a case in which a request signal and a window signal are misidentified as signals of different processes may occur in a GPON which may configure headers according to a situation without having a fixed header format. .

The present invention has been proposed to solve the above problems, and in order to prevent a case in which a request signal and a window signal are misidentified as signals of different processes in the GPON, This is a method of registering an ONU in a gigabit passive optical subscriber network by creating a GTC control frame that adds an identification field for distinguishing a request frame and a window frame.

In order to achieve the above object, the present invention provides a method of registering an ONU in a Gigabit-capable Passive Optical Network (hereinafter referred to as "GPON"), wherein the OLT is used for registration of the ONU. A first step of generating a request frame including a request field for indicating one of the processes and identifying each process, and delivering the request frame to an ONU to be registered; And a second step of performing, by the ONU receiving the request frame, generating and delivering a Window frame indicating that the request frame is a response to the request frame.

The present invention also provides a method of registering an ONU in a Gigabit-capable Passive Optical Network (hereinafter referred to as "GPON"), wherein the OLT is one of the procedures for registering the ONU. In order to indicate that the process and to identify each process, the first step of generating a request frame with a specific ID value specified to pass to the ONU to register; And a second step of performing the process identified and requested by the ONU receiving the request frame, and generating and delivering a window frame indicating that the response is a response to the request frame.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the same components in the drawings are represented by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

As a method for indicating that the procedure is for ONU registration in GPON, the present invention proposes a method of using a reserved field in a PCBd frame and a method of using an ONU_ID field. 8 to 13 illustrate an example of applying the method to the power leveling process. Although not shown in the figure, it is obvious that the request and window of other processes are applied in the same way.

8 is a structural diagram of an embodiment of a control frame for indicating that a request frame of a process for registering an ONU in a GPON using a hold field according to the present invention.

As shown in FIG. 8, the reserved field 310 is used in the Ident field 302 in the PCBd field 31 to indicate that it is a request frame of the process for ONU registration in GPON using the reserved field. It further includes a Request field 81 composed of at least two bits. The reason for configuring at least 2 bits is that at least 2 bits are required because there are three processes to display: Power Leveling Process, Serial Number Process, and Ranging Process.

9 is a structural diagram of a second embodiment of a control frame for indicating that a request frame of a process for registering an ONU in a GPON using a hold field according to the present invention.

As shown in FIG. 9, the reserved field 316 in the US BW map field 307 in the PCBd field 31 is used to indicate that it is a request frame of a process for ONU registration in GPON using the reserved field. It further includes a request field 91 composed of at least two bits. The reason for configuring at least 2 bits is that at least 2 bits are required because there are three processes to display: Power Leveling Process, Serial Number Process, and Ranging Process.

FIG. 10 is a structural diagram of a third embodiment of a control frame for indicating that a request frame of a process for registering an ONU in a GPON is performed using a hold field. FIG.

As shown in FIG. 10, the reserved field 310 and the PCBd field (in the Ident field 302 in the PCBd field 31) are used to indicate that this is a request frame of a process for ONU registration in GPON using the reserved field. A flag field 1001 indicating a control frame for ONU registration using a pending field 316 in US BW map field 307 in 31 and a Request field 1006 indicating which of the processes for ONU registration are performed. ). According to the embodiment shown in FIG. 10, the pending field 310 in the Ident field 302 in the PCBd field 31 includes a flag field 1001 indicating that it is a control frame for ONU registration, and the PCBd field ( In the pending field 316 in the US BW map field 307 in 31), it is proposed to include a Request field 1006 indicating which of the processes for the ONU registration, but may be configured in other formats. .

FIG. 11 is a diagram illustrating a structure of a control frame for indicating that a request frame for a process for registering an ONU in a GPON using the ONU_ID field according to the present invention.

As shown in FIG. 5 to FIG. 7, if the control frame presented in the GPON draft is ONU_ID (where ONU_ID means Alloc_ID of 312 in FIG. 3), this is a control frame for ONU registration. It is proposed to identify with.

The method for indicating the request frame for the process of registering the ONU in the GPON using the ONU_ID field proposed in FIG. 11 is a specific ONU_ID used when the control frame for the ONU registration whose ONU_ID value is "254". In order to distinguish the request corresponding to each process by extending it, a different ONU_ID 1101 is assigned to each request of each process. However, this case applies only to the Power Leveling process and the Serial Number process, and may not be applied to the Ranging process after ONU-ID is assigned to each ONU.

For example, the case where the ONU_ID value is "250" may be a request frame for the power leveling process, and the case where the ONU_ID value is "252" may be a request frame for the serial number process.

12 is a diagram illustrating a structure of a control frame for indicating that the frame is a window frame of a procedure for registering an ONU in a GPON according to the present invention.

As shown in FIG. 12, in order to indicate that the window frame is in the process of registering the ONU in the GPON, a window field 1202 including at least two bits is further included in the PLOu field 41. The reason for configuring at least 2 bits is that at least 2 bits are required because there are three processes to display: Power Leveling Process, Serial Number Process, and Ranging Process.

FIG. 13 is a diagram illustrating a structure of a control frame for displaying a window frame in a procedure for registering an ONU in a GPON using the ONU_ID field according to the present invention.

As shown in FIG. 5 to FIG. 7, if the control frame presented in the GPON draft is ONU_ID (where ONU_ID means Alloc_ID of 312 in FIG. 3), this is a control frame for ONU registration. It is proposed to identify with.

The method for displaying the window frame of the process for registering ONU in GPON by using the ONU_ID field proposed in FIG. 11 is a specific ONU_ID used when the control frame for ONU registration whose ONU_ID value is "254". In order to distinguish the window corresponding to each process by extending it, a different ONU_ID 1301 is assigned to each window of each process. However, this case applies only to the Power Leveling process and the Serial Number process, and may not be applied to the Ranging process after ONU-ID is assigned to each ONU.

For example, the case where the ONU_ID value is "251" may be a window frame for the power leveling process, and the case where the ONU_ID value is "253" may be a window frame for the serial number process.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, the present invention can distinguish each request frame and window frame from a different process in the power leveling process, SN process, and ranging process defined in GPON of FSAN / ITU-T SG15 Q2, which is currently being standardized. It is effective to make efficient process execution by using identifiers that exist.

Claims (12)

In the method of activation of the ONU (Optical Network Unit) in a Gigabit-capable Passive Optical Network (hereinafter referred to as "GPON"), A first step of indicating that an optical line termination (OLT) is one of the processes for registering the ONU, and generating a request frame including a request field for identifying each process and delivering the request frame to an ONU to be registered; And And a second step of performing, by the ONU receiving the request frame, generating and transmitting a Window frame indicating that the request frame is a response to the request frame. The method of claim 1, The Request field is A method for registering an ONU in a GPON, comprising: at least two bits in a downstream control frame from an OLT to an ONU using a reserved field present in an Ident field in a physical control block downstream (PCBd) field. The method of claim 1, The Request field is In the downstream control frame from the OLT to the ONU, the ONU registration method in GPON, characterized in that it is configured with at least 2 bits using the pending field present in the US BW map field in the PCBd field. The method of claim 1, The request frame, In the downstream control frame from the OLT to the ONU, a flag field indicating the control frame for registering the ONU and a procedure for registering the ONU using the hold field present in the Ident field and the US BW map field in the PCBd field. ONU registration method in GPON, characterized in that the request frame configured to further include a request field indicating which of the process. The method of claim 1, The Window frame is In the upstream control frame from ONU to OLT, In the GPON, characterized in that the Window frame configured to further include a window field indicating the process of the registration process for the ONU consisting of at least 2 bits or more in the PLOu (Physical Layer Overhead upstream) field of the upstream control frame How to register for ONU. The method of claim 1, The Window frame is In the upstream control frame from ONU to OLT, And a window frame indicating which of the processes for ONU registration is performed by dividing and using field values of the Alloc_ID field present in the PLOu field of the upstream control frame. The method of claim 6, The Window frame is ONU registration method in GPON, characterized in that used in the power leveling process and serial number process. In the activation method of the ONU in a Gigabit-capable Passive Optical Network (hereinafter referred to as "GPON"), In order to indicate that the OLT is one of the processes for registering the ONU, and to identify each process, a first step of generating a request frame having a specific ID value and transmitting the same to the ONU to be registered; And And a second step of performing the process identified and requested by the ONU receiving the request frame, and generating and transmitting a window frame indicating that the request frame is a response to the request frame. The method of claim 8, Request frame in which the specific ID value is specified, In the downstream control frame from the OLT to the ONU, by using the field value of the Alloc_ID field present in the US BW map field in the PCBd field, it is a request frame that indicates which of the processes for the ONU registration process How to register ONU in GPON. The method of claim 8, The Window frame is In the upstream control frame from ONU to OLT, And a Window field configured to further indicate a window field indicating a process of a process for registering an ONU having at least 2 bits in the PLOu field of the upstream control frame. The method of claim 8, The Window frame is In the upstream control frame from ONU to OLT, And a window frame indicating which of the processes for ONU registration is performed by dividing and using field values of the Alloc_ID field present in the PLOu field of the upstream control frame. The method of claim 11, The Window frame is ONU registration method in GPON, characterized in that used in the power leveling process and serial number process.

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