KR100925678B1 - Apparatus for optical line terminal and apparatus for optical network terminal - Google Patents

Abstract

The present invention relates to an optical line terminal device and an optical network termination device, the optical line terminal device comprising: an optical transmission / reception module; A SERDES connected to the optical transmission / reception module to perform physical media access (hereinafter, referred to as PMA) sublayer processing; And a fiber termination device (hereinafter referred to as a malfunctioning fiber termination device) that receives at least one of a loss of signal (LOSS) signal and a signal detection signal (SD) signal from the SERDES and continuously transmits an optical signal. It includes a detection unit for detecting. According to the present invention, it is possible to detect an optical network termination device that continuously transmits an optical signal or to block optical signal transmission of a malfunctioning optical network termination device, thereby securing stability of a passive optical network (hereinafter referred to as a PON). can do.

PON, OLT, ONU, ONT

Description

Optical line terminal device and optical network terminal device {apparatus for optical line terminal and apparatus for optical network terminal}

1 is a diagram illustrating a PON.

2 is a diagram conceptually illustrating a data flow between an OLT and a registered ONU in GE-PON.

3 is a block diagram showing a configuration of an optical line terminal apparatus according to an embodiment of the present invention.

4 is a diagram illustrating a structure of an uplink frame in a PON.

5 is a block diagram showing the configuration of an optical network termination device according to an embodiment of the present invention.

The present invention relates to a PON, and more particularly, to an optical line terminal device and an optical network termination device that can ensure the stability of the PON.

Recently, as an optical subscriber network technology for efficiently providing various multimedia contents, it is easily applied to Fiber To The Home (FTTH), Fiber To The Neighborhood (FTTN), Fiber To The Premise (FTTP), and Fiber To The Curb (FTTC). Many PON technologies are available.

As shown in FIG. 1, the PON connects to another network and a service node interface (hereinafter referred to as SNI) to start an PON, and the optical line terminal (OLT) to start the PON and optical fibers from the OLT. It consists of a passive splitter that splits into multiple strands of fiber, a plurality of optical network units (ONU) or / and an optical network terminal (ONT). Each of the ONU and ONT is connected to at least one subscriber station through a user network interface (hereinafter, UNI).

In this way, PON is composed of point-to-multipoint method between OLT and ONU / ONT, and should use multiplexing method, and TDM (A) -PON using time division multiplexing (TDM) according to the multiplexing method. It is roughly classified into WDM (A) -PON using Wavelength Division Multiplexing (WDM). TDM (A) -PON uses ATM-PON based on Asynchronous Transfer mode (ATM), (G) E-PON based on Ethernet, and G-PON using general frame protocol depending on protocol used. Etc.

As one example of TDM (A) -PON, GE-PON defined in IEEE802.ah standard transmits downlink data and transmits uplink data by TDMA method using wavelength of 1310nm, 1490nm and 1550nm. It has an asymmetric structure. GE-PON provides registration for ONU / ONT, ranging to enable time slot-based transmissions with accurate timing, and dynamic bandwidth allocation for ONU / ONT. DBA), the Multi-Point Control Protocol (MPCP) is used.

The MPCP is briefly described as follows. First, a logical link identifier (LLID) is assigned to the ONU / ONT through the discovery process of the MPCP so that the ONU / OLT is registered in the OLT, and the lasing is performed through the discovery process or a separate process. The round trip time (RTT) of each ONU / ONT is calculated from the OLT. In addition, through the DBA process of MPCP, the OLT allocates an uplink time slot to each registered ONU / ONT, and then the ONU / ONT transmits uplink data using the allocated uplink time slot. For the above-described registration, ranging, and DBA, a gate message broadcast by the OLT, a report message transmitted by each ONU / ONT to the OLT, and the like are used.

2 is a diagram conceptually illustrating a data flow between an OLT and a registered ONU in GE-PON.

The flow of downlink data is described first as follows. The OLT carries traffic data for the ONU in each frame, and inserts the LLID of the ONU in the preamble of the frame and transmits the data. Thereafter, each ONU detects a frame corresponding to its LLID among the frames received from the OLT and delivers the frame to the UNI.

The flow of upstream data is as follows. Based on the report message containing the queue information of the ONU / ONT, the OLT allocates a band, that is, an uplink time slot, to the registered ONU. Thereafter, the ONU transmits the traffic data received from the subscriber station to the OLT using the allocated uplink time slot.

As described above, in the PON using the TDM (A) method for uplink transmission, it can be seen that each ONU / ONT should transmit data using only the uplink time slot allocated to it to prevent transmission collision between ONU / ONT. have.

In other words, when one ONU / ONT (hereinafter, malfunction ONU / ONT) malfunctions and continuously transmits an optical signal due to a failure of the optical transmission / reception module or a malfunction of the module controlling the optical transmission / reception module, the remaining ONU / ONT (hereinafter referred to as normal ONU / ONT) may be a situation that can not receive normal PON service. For example, when the remaining ONU / ONT is already registered and transmits uplink data, the OLT is received from the normal ONU / ONT because the signal continuously transmitted by the malfunctioning ONU / ONT and the signal received from the normal ONU / ONT overlap. The signal cannot be detected properly. As a result, since the upcoming communication of the registered ONU / ONT is not properly performed, a response message (eg, a report message) necessary for maintaining the registration may not be properly transmitted to the OLT, and thus a situation may be released. As another example, if the remaining ONU / ONT is not yet registered and wants to register through the above-described discovery process, the uplink communication required for the discovery process is not performed properly in the same principle, and as a result, the registration is not registered even if it is registered. Failure can occur.

Therefore, there is a need for a way to solve the problem to ensure the stability of the PON.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an optical line terminal device and an optical network termination device capable of blocking optical transmission by a malfunctioning optical network termination device.

Another object of the present invention is to provide an optical line terminal device for detecting the presence of a malfunctioning optical network termination device continuously transmitting an optical signal and a malfunctioning optical network termination device.

In order to achieve the above technical problem, a first aspect of the present invention provides an optical transmission / reception module; A signal converter configured to perform serial-to-parallel signal conversion on signals exchanged with the optical transceiver module; A detection unit for determining that a failure has occurred in the transmission of the optical signal of the optical network termination device through the signal from the signal conversion unit; And a controller configured to generate a control signal for the corresponding optical network termination device according to the failure occurrence determination of the detection unit.

In order to achieve the above technical problem, a second aspect of the present invention provides an optical transceiver module; A SERDES connected to the optical transmission / reception module to perform physical media access (hereinafter, referred to as PMA) sublayer processing; And a fiber termination device (hereinafter referred to as a malfunctioning fiber termination device) that receives at least one of a loss of signal (LOSS) signal and a signal detection signal (SD) signal from the SERDES and continuously transmits an optical signal. An optical line terminal device including a detection unit for detecting is provided.

In order to achieve the above technical problem, a third aspect of the present invention provides an optical transmission / reception module; Whether the output signal of the optical transceiver module periodically has a voltage value lower than a predetermined level, whether the same bit value of a predetermined length is periodically obtained from the output signal, and whether sink data is periodically detected from the output signal; The present invention provides an optical line terminal device including a detector configured to monitor at least one of whether or not a failure occurs due to the existence of an optical network termination device that continuously transmits an optical signal.

In order to achieve the above technical problem, a fourth aspect of the present invention provides an optical transmission / reception module; And when it is determined that there is at least one optical network terminator (hereinafter referred to as a malfunctioning optical network terminator) for performing continuous optical signal transmission in a situation where one optical network terminator is registered, the malfunctioning optical network terminator Provided is an optical line terminal device including a control unit that determines to be.

In order to achieve the above technical problem, a fifth aspect of the present invention provides an optical transmission / reception module; And a blocking unit which blocks an optical transmission of the optical transmission / reception module when an optical transmission blocking message for stopping the optical transmission is received.

Hereinafter, embodiments of the present invention for solving the above technical problem are described with reference to the accompanying drawings.

As used herein, the term “apparatus for optical line terminal” is used as a term encompassing an apparatus (eg, OLT) for transmitting and receiving an optical signal in a point-to-multipoint relationship with a plurality of ONU / ONTs in a PON. The term "apparatus for optical network terminal" will be used as a term encompassing a device (eg, ONU, ONT) that transmits and receives an optical signal in a multi-point-to-point relationship with the optical line terminal device in the PON.

3 is a block diagram showing a configuration of an optical line terminal apparatus according to an embodiment of the present invention. Referring to FIG. 3, the optical line terminal device of the present embodiment includes an optical transmission / reception module 300, a SERDES 310, a detector 320, and a controller 330.

The optical transmission / reception module 300 is in charge of processing a physical media dependency (PMD) sublayer of a PON. That is, for transmission, the optical signal received from the PON interface is photoelectrically converted, and the conversion result signal S1 is provided to the SERDES 310. In addition, for reception, the optical transmission / reception module 300 transmits the optical signal through the PON interface by converting the signal S1 provided from the SERDES 310 in accordance with the enable signal.

The SERDES 310 is responsible for the PON sublayer processing of the PON. That is, for reception processing, the SERDES 310 converts the signal S1 provided from the optical transmission / reception module 300 into deserializing, that is, parallel data (for example, 10-bit data) S2, and controls the same. Provided at 330. As a more detailed example, as shown in FIG. 3, the parallel data S2 is provided to the PON MAC controller 334 to perform the processing after the forward error correction (FEC) sublayer or higher layer processing is performed. The result is provided to the service node interface.

In addition, for transmission processing, the SERDES 310 converts the parallel data S2 provided from the control unit 320 into a serializing, that is, a 1-bit, signal S1 to the optical transmission / reception module 300. to provide. As a more detailed example, as shown in FIG. 3, when the PON MAC controller 334 performs the layer processing of the FEC sublayer or more, for the data provided from the service node interface, the processed data S2 is SERDES 310. Is provided.

The detection unit 310 detects whether there is a malfunctioning optical network termination device that continuously transmits a strong signal to the PON through the failure detection method of the present invention. The failure detection method according to the present invention will be described later.

When a failure is detected by the detector 310, the controller 330 detects the malfunctioning optical network termination device and performs control to finally block light transmission by the detected malfunctioning optical network termination device. As a more detailed example, as shown in FIG. 3, when the controller 330 includes a CPU 332 in charge of overall device control and a PON MAC controller 334 performing the above-described processing, the CPU 332 is used. Instructs the PON MAC controller 334 to send the detected malfunctioning optical fiber termination device to the PON MAC controller 334, and the PON MAC controller 334 receiving the command generates an optical transmission blocking message directed to the malfunctioning optical fiber termination device. To the SERDES 310. Thereafter, the SERDES 310 deserializes the optical transmission blocking message and provides the optical transmission / reception module 300 to the optical transmission / reception module 300, and the optical transmission / reception module 300 transmits the corresponding optical signal to the PON interface. As a result, the malfunctioning optical network termination device stops optical transmission by the method described later in FIG.

Preferably, the light transmission block message is transmitted through an OAM (Operation, Administration and Maintenance) frame.

Hereinafter, a method of detecting the presence of a malfunctioning optical network termination device according to the present invention will be described.

4 is a diagram illustrating a structure of an uplink frame in a PON.

In FIG. 4, T1 represents an uplink time slot, i.e., a grant period, assigned to the first fiber termination device, and T3 represents an uplink time slot, i.e., a grant period, allocated to the second optical fiber termination device. T2 is a period during which uplink transmission is prohibited to ensure that uplink transmission using the grant period T3 is properly performed, that is, a grant spacing period, wherein a laser diode including the first optical network termination device included in the optical transceiver module, T2_1, which is a time required to turn off an optical signal source such as a light emitting diode, and T2_2, which is a time required to turn on an optical signal source of the second optical network termination device.

The period denoted by DATA is a period during which the uplink traffic data of the optical fiber termination device is transmitted, and the period denoted by Idle is a period during which the sink data (eg, sink data of K28.5) of the optical fiber termination device is transmitted. T3_1, which is part of the approval period T3, is a synchronization time (Sync Time) in which synchronization between the second optical network termination device and the optical line terminal device is performed. Here, the synchronization data has a specific data pattern that the optical line terminal device and the optical network termination device know each other.

The fault detection method of the present invention (i.e., the method of detecting the presence of a malfunctioning optical network termination device) has the following two embodiments as a method utilizing the nature of the above-described approved spacing period.

First, the failure detection method according to the first embodiment of the present invention will be described. The method may be applied to the case where the SERDES 310 has at least one of a detection function for a loss of signal (LOSS) and a signal detection (SD) function. 310 provides the LOSS signal and the SD signal to the detector 320 through the first signal path.

Here, the LOSS signal is input to the SERDES 310 from the optical transmission / reception module 300 under a first condition in which the voltage level of the signal input from the optical transmission / reception module 300 to the SERDES 310 is less than or equal to a predetermined value (eg, 200 mV). At least one of a second condition in which data obtained from the signal is all "0000000000" or all "1111111111", and a third condition in which sync data is not detected from the signal input to the SERDES 310 from the optical transmission / reception module 300 for a predetermined period of time. If not satisfied, the signal has an activation value (eg, HIGH) and otherwise has a deactivation value (eg, LOW).

In addition, the SD signal has a deactivation value (for example, LOW) when at least one of the first condition, the second condition, and the third condition is not satisfied, and is otherwise a signal having an activation value (for example, HIGH).

Referring to the nature of this signal and the above description of FIG. 4, the LOSS signal has an inactivation value and the SD signal has an activation value during the grant period. Similarly, the LOSS signal has an active value and the SD signal has an inactive value during acknowledge spacing.

Therefore, when there is no malfunction optical network termination device that continuously transmits the optical signal to the PON, it can be seen that the LOSS signal has an activation value and an inactive value periodically, and the SD signal has the same property.

Using this property, according to the presence detection method of the malfunctioning optical network termination apparatus according to the first embodiment of the present invention, the detection unit 320 is the case that the LOSS signal is not periodically activated or the SD signal is not periodically disabled Then, it is determined that a malfunctioning optical network termination device exists.

In addition, as another embodiment using the LOSS signal and the SD signal, the detector 320 determines that a malfunctioning optical network termination device exists when the LOSS signal is inactive or the SD signal is activated for a predetermined period of time. Preferably, the predetermined period is a period longer than the period during which the optical signal source is turned on for the maximum transmission of the maximum duration allowed for one optical network termination device in the passive optical subscriber network. The activation of the SD signal during the predetermined time period means that there is an optical network termination device that transmits the optical signal even during at least a part of the approval spacing period.

On the other hand, as an example of implementing such a detection method, the detection unit 320 samples and counts an SD signal according to a predetermined clock to determine whether it is activated for the predetermined period, and then if it is not activated for the predetermined period (that is, , If it is determined that a failure has not occurred, writes a first value (e.g., 0) to the register, and if activated for the predetermined period of time (i.e., determines that a failure has occurred), a second value (e.g., 1) is written to the register. Record it. The CPU 332 periodically monitors this register to know whether a malfunctioning fiber termination device exists in the PON, that is, whether or not a failure has occurred.

Next, a failure detection method according to a second embodiment of the present invention will be described. This method is a method in which the detector 320 detects the signal S1 provided from the second signal path instead of the first signal path, that is, the output signal of the optical transmission / reception module 300. It uses the same properties as the fault detection method.

According to the detection method according to the present exemplary embodiment, the detection unit 320 periodically determines whether the output signal of the optical transmission / reception module 300 has a voltage value lower than a predetermined level or periodically from the output signal of the optical transmission / reception module 300. Whether or not the same bit value of the length is obtained, and whether or not sync data is periodically detected from the output signal of the optical transmission / reception module 300, thereby monitoring the presence of a malfunctioning optical network termination device that continuously transmits the optical signal. Detect.

Meanwhile, since the SERDES 310 receives the output signal of the optical transmission / reception module 300 like the detection unit 320, unlike the example illustrated in FIG. 3, the SERDES 310 does not exist separately, but the SERDES 310 does not exist separately. It can be fully understood by those skilled in the art that there may exist an embodiment in which the above-described operation of the detector 320 according to the second embodiment may exist.

Hereinafter, a method of detecting a malfunctioning optical network termination device and removing the obstacle according to the present invention will be described.

In the case where a malfunctioning optical network termination device that continuously transmits an optical signal exists in the PON, the optical line terminal device generally cannot normally receive an uplink transmission signal necessary for maintaining the registration of the remaining optical network termination device, and thus, the malfunctioning optical network. All other fiber termination devices except for the termination device are deregistered.

Therefore, by using this property, when there is one registered optical network termination device in detecting a failure, the malfunctioning optical network device can be detected and the failure can be eliminated by the following method.

First, the case 1 (if there is one malfunctioning optical network terminator and one registered optical network terminator) detects the malfunctioning optical network terminator and removes the obstacle as follows. When a failure is detected through the above-described failure detection method or the like, the control unit 330 (specifically, the CPU 332) may malfunction the optical network termination device that is registered and maintained if there is only one optical network termination device that is currently registered and held. After detecting that it is a terminating device, a second optical transmission blocking message is transmitted to the detected malfunctioning optical network terminating device, thereby eliminating an obstacle.

Secondly, in case 2 (when there are a plurality of malfunctioning optical network termination devices and one registered optical network termination device), the method of detecting the plurality of malfunctioning optical network termination devices and removing the obstacles is as follows. For convenience, there are two malfunctioning optical network terminators (the first malfunctioning optical network terminator and the second malfunctioning optical network terminator) in the PON, and because of the first malfunctioning optical network terminator, the remaining optical network terminator including the second malfunctioning optical network terminator. It will be described on the premise that the situation is unregistered. When a failure is detected through the above-described detection method of the malfunctioning optical network termination device or the like, if there is only one optical network termination device currently registered and held, the controller 330 uses the same method as in Case 1 to terminate the registered optical network termination. The device (that is, the first optical network termination device) is determined to be a malfunctioning optical network termination device, and the optical signal transmission of the first optical network termination device is blocked by a method such as transmission of the second optical transmission blocking message. Thereafter, the second malfunctioning optical network termination device may be registered and a failure may be detected again. In this case, similarly, if the currently registered optical network terminating device is one, the registered optical network terminating device (ie, the second malfunctioning operation) may be detected. The optical network termination device) is determined to be a malfunctioning optical network termination device, and the optical signal transmission of the second optical network termination device is interrupted by a method such as the transmission of the second optical transmission blocking message, thereby finally eliminating the obstacle.

5 is a block diagram showing the configuration of an optical network termination device according to an embodiment of the present invention.

Referring to FIG. 5, the optical network terminating apparatus of the present embodiment includes an optical transmission / reception module 500, a control unit 510, and a blocking unit 520.

The optical transmission / reception module 500 transmits an optical signal by totally converting a signal provided from the control unit 510 under the control of the control unit 510, or photoelectrically converts an optical signal received through a PON interface. To provide.

The controller 510 performs an operation (eg, a central control operation, a MAC processing operation, a packet processing operation, an MPCP processing operation, etc.) to perform a function of the optical network termination device of the PON. In addition, the controller 510 controls the blocking unit 520 to block the optical transmission of the optical transmission / reception module 500 when the above-described optical transmission blocking message is received through the optical transmission / reception module 500. Preferably, the light transmission block message is received via an OAM (Operation, Administration and Maintenance) frame.

The blocking unit 520 blocks the optical transmission / reception of the optical transmission / reception module 500 by stopping power supply to the optical signal source of the optical transmission / reception module 500 under the control of the controller 510.

Such a method and apparatus of the present invention have been described with reference to the embodiments shown in the drawings for clarity, but these are merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

According to the present invention, the optical transmission by the malfunctioning optical network termination device can be interrupted and the stability of the PON can be ensured.

Further, according to the present invention, even in a PON environment in which there is an optical network termination device that cannot diagnose whether or not a malfunction itself, the existence of the optical network termination device that malfunctions and continuously transmits an optical signal, and the malfunctioning optical network termination device can be detected. Can be.

Claims (13)

Optical transceiver module; Perform serial-to-parallel signal conversion on a signal exchanged with the optical transmission / reception module, whether the signal has a voltage value lower than a predetermined level, whether the same bit value of a predetermined length is obtained from the signal, and within the predetermined period A signal converter configured to monitor at least one or more of whether sync data is detected in the signal to generate a first signal; A detector configured to monitor the first signal generated by the signal converter and determine that a failure occurs in the optical signal transmission of the optical network termination device when the first signal does not repeat periodically; And And a controller for transmitting a control signal to block the optical signal transmission to the registered optical network termination device when it is determined that the failure occurs in the detection unit. delete The method of claim 1, wherein the control signal, Optical line terminal device characterized in that transmitted through the OAM (Operation, Administration and Maintenance) frame. The method of claim 1, wherein the signal conversion unit, And an SERDES for converting a signal from the optical transmission / reception module into parallel data and converting a signal to be transmitted to the optical transmission / reception module into serial data. Optical transceiver module; Is connected to the optical transmission / reception module to perform a physical media access (PMA) sublayer processing, and whether the signal received from the optical transmission / reception module has a voltage value lower than a predetermined level, and the optical Generating a first signal by monitoring at least one of whether the same bit value of a predetermined length is obtained from a signal received from the transmission / reception module, and whether or not sync data is detected within a predetermined period from the signal received from the optical transmission / reception module; SERDES; When the first signal is received from the SERDES and the first signal does not repeat activation and deactivation periodically, a failure occurs due to the existence of an optical network terminator (hereinafter referred to as a malfunctioning optical network terminator) that continuously transmits an optical signal. Detecting unit for detecting whether or not; And And a controller for transmitting a control signal to block the optical signal transmission to the registered optical network termination device when it is determined that the failure occurs in the detection unit. delete The method of claim 5, wherein the detection unit And determining that the failure has occurred when the first signal is deactivated for a predetermined period or longer or when the first signal is activated for a predetermined period or longer. The method of claim 7, wherein the predetermined period of time An optical line terminal device comprising a period longer than a period in which an optical signal source is turned on for uplink transmission of a maximum duration allowed in one optical network end device in a passive optical subscriber network. delete delete delete delete delete

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