JP2008028451A - Optical subscriber communication system, abnormal light emission preventing method for optical subscriber device in optical subscriber communication system, and program thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an optical subscriber communication system capable of detecting an optical subscriber device in which an optical output prohibiting function does not work, and solving a status in which other optical subscriber devices cannot perform communication due to the optical subscriber device whose optical output prohibition function does not work. <P>SOLUTION: In the optical subscriber communication system, an in-station device (OLT) 1 causes a control section 107 to detect an abnormality of an optical subscriber device (ONU) 2, transmits a signal including a light emission stop command for stopping light emission to the device 2 in which the abnormality is detected together with an optical link termination section 103, and the device 2 stops its own light emission using a data processing section 210 on the basis of the transmitted light emission stopping command. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical subscriber communication system, an abnormal light emission suppression method for an optical subscriber unit in an optical subscriber communication system, and a program thereof, and more particularly, to suppress abnormal light emission of a specific optical subscriber unit (ONU: Optical Network Unit). GE-PON (Gigabit Ethernet Passive Optical Network) system (Ethernet is a registered trademark) and optical subscriber unit in the GE-PON system that can restore the operation of all other optical subscriber units (ONUs) normally The present invention relates to (ONU) abnormal light emission suppression method and program thereof.

One GE-PON system that connects in-station equipment (OLT: Optical Line Terminal), a plurality of optical subscriber units (ONU), and the OLT and the plurality of ONUs in a star configuration via an optical coupler If the optical output prohibition function of the ONUs of this device stops functioning, there is a problem that all other ONUs cannot communicate.

This problem is subdivided into the following two problems. In other words, there are two problems: an ONU in which the optical output prohibition function is not functioning cannot be detected, and a state where all other ONUs cannot communicate cannot be resolved.
Before describing the above-described conventional problems, here, first, the mechanism of the GE-PON system will be described.

The GE-PON system is now spreading as one means for economically increasing the capacity and speed of access networks using optical fibers.
FIG. 1 shows the configuration of a subscriber access network of the GE-PON system.
The subscriber access network of the GE-PON system includes an intra-station device (OLT) 1, a plurality of optical subscriber units (ONU) 2A to 2C, an optical coupler 3, and an optical fiber connecting them. The OLT 1 is installed in a station building, and the optical coupler 3 is installed in a subscriber house, an apartment house, a building, etc. away from the station building, and accommodates subscriber lines from a plurality of ONUs 2A to 2C.
The optical coupler 3 is a device for branching / collecting light. The connection devices 4A to 4D are communication devices such as routers, switching hubs, and personal computers.

Next, a communication (frame transfer) mechanism in this system will be described.
In the GE-PON system, a frame transmitted in the direction from the in-station device (OLT) 1 to the optical subscriber unit (ONU) 2A-2C is a downlink frame, and a frame transmitted in the direction from the ONU 2A-2C to OLT1 is an uplink frame. It expresses.
The section from the OLT 1 to the ONUs 2A to 2C via the optical coupler 3 is an independent communication path by wavelength division multiplexing in the upstream direction and the downstream direction. Therefore, the upstream frame and the downstream frame can pass over the optical fiber at the same time. However, each of the ONUs 2A to 2C is configured to share a communication path in the uplink direction or the downlink direction. Therefore, upstream frames or downstream frames cannot pass on the optical fiber at the same time. The sharing will be described later.

FIG. 2 shows how the forward frame is transferred.
Downlink frames to be transmitted from the intra-station device (OLT) 1 to the plurality of optical subscriber units (ONUs) 2A to 2C connected to the optical coupler 3 are time-division multiplexed on the same optical fiber transmission line, and the optical coupler 3 The ONUs 2A to 2C connected to the optical coupler 3 are broadcast and distributed, so that each ONU extracts only a frame addressed to itself and discards frames addressed to other ONUs. .

FIG. 3 shows how the uplink frame is transferred. When transmitting frames from each ONU to the OLT 1, each upstream frame sequence transmitted from a plurality of ONUs 2 </ b> A to 2 </ b> C is merged by the optical coupler 3, so that collision between frame sequences transmitted from different ONUs is prevented. Each ONU adjusts the transmission timing of the frame sequence and sends it out. Here, the frame sequence indicates a plurality of frames. The transmission timing of the frame sequence is instructed from the OLT 1 to each of the ONUs 2A to 2C. Since a plurality of frames can be transmitted within one transmission opportunity within a period of receiving an instruction from the OLT 1, the expression “frame sequence” that handles a plurality of frames as one lump is used.

FIG. 4 shows, as a supplement to FIG. 3, how the upstream frame sequences transmitted from each of the ONUs 2 </ b> A to 2 </ b> C merge at the optical coupler 3 with respect to time on the horizontal axis. What is important in upstream frame transmission is that a frame can be transmitted at a certain time, more simply, only one ONU may emit light (output an optical signal to the optical coupler 3) at a certain time. It is that.
This completes the description of the GE-PON mechanism.

Next, problems in the conventional GE-PON system will be described in more detail with reference to FIG.
FIG. 10 shows a configuration of a conventional GE-PON system. In FIG. 10, an in-station device (OLT) 12, optical subscriber units (ONU) 22A to 22C, an optical coupler 32, and connection devices 42A to 42D are shown in FIG. 3 is a conventional apparatus having functions corresponding to the OLT 1, the optical subscriber units (ONU) 2A to 2C, the optical coupler 3, and the connected devices 4A to 4D.
FIG. 10 shows the internal configuration of the ONU 22A. The ONUs 22B and 22C have the same internal configuration. In order for the GE-PON system to operate normally, the ONU 22A outputs (emits) an optical signal from the optical / electrical converter 221 to the optical coupler 32 at a time that is not a transmission opportunity of the ONU 22A. should not.

The light emission prevention except for this transmission opportunity is performed by the following method.
In this method, the optical output permission / prohibition signal 228 output from the optical link termination unit 223 is set to the polarity of “optical output prohibition”, and the optical output permission / prohibition function execution unit 229 built in the optical / electrical conversion unit 221 is used. Therefore, the optical output of the optical / electrical converter 221 is prohibited.
When the optical output is prohibited from the optical output permission / prohibition function execution unit 229, the optical / electrical conversion unit 221 transmits an optical signal to the optical coupler 32 regardless of the electric signal received from the serial / parallel conversion unit 222. Is not output.

However, when the optical output prohibition function of the ONU 22A stops functioning, the above-described light emission prevention is not performed, and the optical / electrical conversion unit 221 always performs serial / serial regardless of whether or not it is a transmission opportunity of the ONU 22A. The electrical signal received from the parallel conversion unit 222 is converted into an optical signal and output to the optical coupler 32.

The case where the optical output prohibition function of the ONU 22A stops functioning specifically shows the following two cases.
First, when the optical output permission / prohibition signal 228 is normal but the optical output prohibition function of the optical output permission / prohibition function execution unit 229 becomes ineffective, the other is to execute the optical output permission / prohibition function. The unit 229 is normal, but the light output permission / prohibition signal 228 does not change from the “light output permission” polarity.

It will also be mentioned what signals are output except for the transmission opportunity of the ONU 22A when the optical output prohibition function of the ONU 22A stops functioning.
The optical link termination unit 223 of the ONU 22A outputs an idle pattern to the serial / parallel conversion unit 222 when it is not a transmission opportunity of the ONU 2A, and the serial / parallel conversion unit 222 receives the idle pattern input from the optical link termination unit 223. Is output to the optical / electrical converter 221. The optical / electrical converter 221 converts the idle pattern input from the serial / parallel converter 222 into an optical signal and outputs the optical signal to the optical coupler 32 when the optical output prohibiting function does not function.
Therefore, when the optical output prohibition function of the ONU 22A does not function, the ONU 22A continues to transmit an idle pattern optical signal to the optical coupler 32 at a time other than the transmission opportunity of the ONU 22A.

Further, if the optical signal (idle pattern) continues to be output from the ONU 22A in addition to the transmission opportunity of the ONU 22A, the transmission frame from the ONU 22B and 22C collides with the idle pattern from the ONU 22A, and the ONU 22B and 22C A frame cannot be transmitted to the OLT 12.
Since the OLT 12 has a function of canceling a logical link with an ONU that cannot periodically receive an uplink frame, the ONUs 22B and 22C have a logical link ID (identification number) for communicating with the OLT 12. ) Will be lost.

Conventionally solved by addressing such a “problem that all optical subscriber units (ONUs) cannot communicate if the optical output prohibition function of one optical subscriber unit (ONU) stops functioning” As a technique, a method has been proposed in which an ONU itself monitors an optical signal output from the ONU, and if the optical signal is detected continuously for a certain period of time, it is determined that the runaway has occurred and is extinguished (see Patent Document 1).
In Patent Document 1, the ONU itself monitors the optical signal output from the ONU, and if the optical signal is detected continuously for a certain period of time, it is determined that the runaway has occurred and is extinguished.

Moreover, although the abnormal state to be solved and the PON system assumed to be applied are different, there is a method disclosed in Patent Document 2 as a similar conventional technique.
This method is intended to solve the situation where the optical subscriber unit (ONU) is continuously lit (“1” of the optical signal continues), and is applied to a PON system different from the GE-PON system. Seems to have been assumed.
In this method, the OTL sequentially designates ONUs one by one, sequentially transmits a signal including a light emission stop command for stopping light emission, and at the timing when the optical signal that has been continuously received disappears. It is determined which ONU is faulty.

JP 2004-32541 A JP 2004-112746 A

  As described above, the conventional GE-PON system cannot detect an optical subscriber unit (ONU) in which the optical output prohibition function is not functioning, and a specific ONU continues to output optical output. There are two problems that cannot solve the state where all other ONUs cannot communicate.

In order to solve such a problem, in Patent Document 1, the ONU itself monitors the optical signal output from the optical subscriber unit (ONU), and if the optical signal is detected for a certain period of time, it is determined that the runaway occurs. To quench the light.
Further, in Patent Document 2, although it cannot be applied as it is to the GE-PON system, a signal including a light emission stop command for stopping light emission by designating ONUs one by one in order is transmitted and continuously received. Since the optical signal disappears, it is determined which ONU has failed.

However, these proposals have the following problems.
The first problem of the invention of Patent Document 1 is that the abnormality (runaway) detected by the optical transceiver (ONU) on the terminal side cannot be known by the optical transceiver (OLT) on the station side. This is because a means for notifying the OLT after detecting an abnormality in the ONU is not provided.
In Patent Document 1, an attempt is made to make the user visually recognize the display by displaying on the LED of the terminal-side optical transmission / reception device. However, in this method, the user looks at the LED and the user grasps the meaning of the LED. And a user who knows the meaning is required to deal with it appropriately.

The second problem of Patent Document 1 is that the device is expensive.
The reason is that since the optical / electrical converter is changed, the price of this part becomes expensive.
The optical / electrical converter is a standard product and is particularly expensive. If you change this, you will not be able to use commercial (standard specification) parts that are distributed in large quantities and have an appropriate price, and use special specification parts with low distribution volume and high cost. It is not economical.

The first problem of the invention disclosed in Patent Document 2 is also a problem that it becomes expensive. The reason for this is that the ONU optical / electrical converter, the ONU optical link termination, and the OLT optical link termination are all special specifications, and they use standard specification parts that have a large distribution volume and a reasonable price. This is because it cannot be done. Furthermore, the addition of a level monitoring circuit makes it more expensive.

Further, as a second problem, there is a problem that some of the operations expected by Patent Document 2 are contrary to the IEEE 802.3ah standard, which is a GE-PON standard.
As a specific example, since the terminal ID is deleted for a slave station that does not receive a response regularly, the operation of instructing the slave station sequentially by specifying the terminal ID from the master station is performed. -Cannot be done within the PON standard.

[Object of invention]
In the present invention, the above-mentioned problems can be solved, and an optical subscriber unit (ONU) that does not function as an optical output prohibition function can be detected. It is an object of the present invention to provide an optical subscriber communication (PON) system, a method of suppressing abnormal light emission of an optical subscriber unit in the PON system, and a program thereof that can eliminate the state in which the ONU cannot communicate.

In order to solve the above problems, an optical subscriber communication system of the present invention comprises an intra-station device, a plurality of optical subscriber devices, an optical coupler provided between the two, and an optical fiber line connecting them. In an optical subscriber communication system for communicating an upstream signal from the optical subscriber unit to the intra-station device and a downstream signal from the intra-unit unit to the optical subscriber unit, the intra-unit unit is the optical subscriber unit Optical subscriber unit abnormality detecting means for detecting an abnormality in the optical subscriber unit, and light emission for transmitting a signal including a light emission stop command for stopping light emission to the optical subscriber unit in which the optical subscriber unit abnormality detecting unit detects an abnormality as the downstream signal A stop command transmission means, and the optical subscriber unit comprises a quenching means for stopping the light emission of the own station based on the light emission stop command sent from the light emission stop command transmission means. The characters (claims 1-7).
Thus, by providing the optical subscriber unit abnormality detection means, it is possible to detect an optical subscriber unit (ONU) where the optical output prohibition function is not functioning, and the detected optical output prohibition function is functioning. It is possible to realize an optical subscriber communication system capable of eliminating a state in which other ONUs cannot communicate due to no ONU.

Here, the optical subscriber unit anomaly detection means includes an idle duration counting function for counting a duration of an idle pattern sent from the optical subscriber unit to the optical coupler during idling, and a logic of the optical subscriber unit. A logical connection state detection function for detecting a connection establishment state, and the count output of the idle duration counting function is longer than a predetermined value determined from the standard of the optical subscriber communication system, and the logic detected by the logical state detection means When only one connection is established, the optical subscriber apparatus currently logically connected is determined to be abnormal (claim 2).
Thereby, it is possible to realize an optical subscriber communication system capable of finding an ONU in which the optical output prohibition function is not functioning from a plurality of optical subscriber units (ONUs) and specifying the ONU.

Here, each content specified as an optical subscriber communication system is regulated by a GE-PON (Gigabit Ethernet Passive Optical Network) system defined in the IEEE 802.3ah standard (claim 3). .
In addition, the specified values are the maximum value of the laser off time, the maximum value of the laser on time, the maximum value of the receiver stabilization time, and the maximum value of the CDR lock time of the GE-PON system defined by the IEEE 802.3ah standard. , The sum of the code group alignment time and the maximum value (claim 4).
As a result, when the actual idle duration exceeds the maximum possible idle duration determined by the GE-PON system standard, the optical subscriber unit (ONU) in which the optical output prohibition function does not function in the system. ) Can be detected.

Further, the quenching means is a data processing means for replacing all the numerical values of the upstream signals with 0 (claim 5).
Thus, the quenching can be realized by setting the numerical value of the ONU output digital signal to 0.

The extinction unit is an optical / electrical conversion power supply control unit that cuts off the power supply to the optical / electrical conversion unit that converts the upstream signal from an electrical signal to an optical signal. .
Further, the extinction means is a transmission power supply control means for cutting off the power supply to the transmission means in the optical / electrical conversion unit for converting the upstream signal from an electric signal to an optical signal (claim 7). .
Thus, extinction can be forcibly realized by cutting off the power supplied to the optical / electrical converter of the ONU or the transmission means in the optical / electrical converter.

In order to solve the above-described problems, an optical subscriber apparatus abnormal light emission suppression method in an optical subscriber communication system according to the present invention is connected to an intra-station apparatus and an intra-station apparatus via an optical fiber line including an optical coupler. A method of suppressing abnormal light emission of the optical subscriber unit in an optical subscriber communication system including a plurality of optical subscriber units, wherein the optical subscription detects an abnormality of the optical subscriber unit executed in the intra-station device. A signal including a light emission stop command for stopping light emission to the optical subscriber unit that has detected an abnormality in the optical subscriber unit abnormality detection step in downlink communication from the intra-station device to the optical subscriber unit A light emission stop command transmission step for transmitting, and a light extinction step for stopping the light emission of the local station based on the light emission stop command transmitted in the light emission stop command transmission step executed in the optical subscriber unit Wherein (claims 8 to 11).
As a result, an ONU in which the optical output prohibition function is not functioning is detected, light emission of the detected ONU is stopped, and a state where other ONUs cannot communicate due to a failure of this ONU can be eliminated. It is possible to realize an abnormal light emission suppression method for a person's device.

Here, the optical subscriber unit abnormality detecting step includes an idle duration counting step for counting a duration of an idle pattern sent from the optical subscriber unit during idle, a count value and light in the idle duration counting step. An idle duration comparison step for comparing with a prescribed value determined from a standard of a subscriber communication system, and a logical connection state detection step for detecting a logical connection establishment state with the optical subscriber unit, and the idle duration time When the count value in the comparison step is longer than the specified value and only one logical connection to be detected in the logical state detection step has been established, it is determined that the optical subscriber unit that is currently logically connected is abnormal. (Claim 9).
As a result, it is possible to realize an abnormal light emission suppression method for an optical subscriber unit that can find an ONU in which the optical output prohibition function is not functioning among a plurality of ONUs, and identify and deal with the ONU.

In order to solve the above-mentioned problems, an abnormal light emission suppression program for an optical subscriber unit in an optical subscriber communication system according to the present invention is connected to an intra-station device via an optical fiber line including an optical coupler. An abnormal light emission suppression program for the optical subscriber unit in an optical subscriber communication system including a plurality of optical subscriber units, an optical subscriber unit abnormality detection function for detecting an abnormality of the optical subscriber unit; Light emission stop command transmission function for transmitting a signal including a light emission stop command for stopping light emission to the optical subscriber apparatus that has detected an abnormality in the optical subscriber apparatus abnormality detection step as downlink communication from the intra-station apparatus to the optical subscriber apparatus. Are executed by a computer of the in-station device (claims 10 to 11).
Accordingly, it is possible to provide an abnormal light emission suppression program for an optical subscriber unit that can cause the computer of the in-station device to detect an ONU in which the optical output prohibition function is not functioning and execute a light emission stop command.

In addition, the optical subscriber unit abnormality detection function includes an idle duration counting function that counts a duration of an idle pattern sent from the optical subscriber unit during idle, and a logical connection establishment state between the optical subscriber unit and the optical subscriber unit. The logical connection state detection function to be detected and the count output by the idle duration counting function are longer than a prescribed value determined from the standard of the optical subscriber communication system, and only one logical connection to be detected by the logical state detection function is established. And an optical subscriber unit abnormality determination function for determining that the currently logically connected optical subscriber unit is abnormal, and causing the computer of the intra-station device to execute these functions. (Claim 11).
As a result, an optical subscriber unit in an optical subscriber communication system capable of identifying an ONU in which the optical output prohibition function is not functioning among a plurality of ONUs and causing the computer of the in-station device to identify the ONU is identified. An abnormal light emission suppression program can be provided.

  Since the present invention is configured as described above, it is possible to detect an optical subscriber unit (ONU) in which the optical output prohibiting function is not functioning. It is possible to provide an optical subscriber communication system capable of eliminating the state in which the ONU cannot communicate, an ONU abnormal light emission suppression method in the optical subscriber communication system, and a program thereof.

Hereinafter, the present invention will be described in detail with reference to the drawings.
First, in FIG. 1, the basic configuration of the subscriber access network of the GE-PON system is shown.
Further, FIG. 2 shows a state of transferring a downstream frame, and FIG. 3 shows a state of transferring an upstream frame. Further, FIG. 4 shows a state in which the upstream frame trains transmitted from the respective optical subscriber units (ONU) 2A to 2C are joined by the optical coupler 3. These basic configurations are not changed in the present invention.

FIG. 5 is a block diagram showing the configuration of the first exemplary embodiment of the present invention.
FIG. 5 shows a case where three ONUs are connected to the optical coupler 3 in the first embodiment. However, the first embodiment can be applied to all cases where two or more ONUs are connected.

  In the first embodiment, the newly added components in the conventional example shown in FIG. 10 are the idle pattern duration counter 108 in the local station (OLT) 1 and each optical subscriber unit ( ONU) is a data processing unit 210.

  The idle pattern duration counter 108 can count the duration of the idle pattern passing through the serial / parallel converter 102, and functions as an idle duration counting function. In addition, the data processing unit 210 can select either a zero signal or a signal output from the optical link termination unit 203 as a signal to be input to the serial / parallel conversion unit 202. It has become. As a result, light emission can be suppressed by selecting zero in the event of an abnormality, whereby the data processing unit 210 functions as a quenching means.

Here, each component of the block diagram of 1st Embodiment shown in FIG. 5 is demonstrated.
The intra-office equipment (OLT) 1 of the first embodiment is suitable for a transformer 106 for insulation, conversion from a signal suitable for transmission on a twisted pair wire to a digital signal, and transmission from a digital signal to a twisted pair wire. A twisted pair link termination unit 105 that performs conversion to a signal, a frame buffer unit 104 that temporarily holds a communication signal, an optical link termination unit 103 that exchanges information with the ONU 2, a conversion from a parallel signal to a serial signal, and A serial / parallel converter 102 having a function of converting a serial signal to a parallel signal, detecting an upstream idle pattern, and notifying the idle pattern duration counter 108, and converting an optical signal into an electrical signal and electrical An optical / electrical converter 101 that performs conversion from a signal to an optical signal is included. Furthermore, an idle pattern duration counter 108 that counts the duration of the idle pattern to detect an abnormality, a recovery time counter 109 that counts a time when no abnormality is found to determine whether the abnormality has been resolved, The control unit 107 collects information from and transmits information to the network administrator.

On the other hand, the optical subscriber unit (ONU) 2A of the first embodiment includes a transformer 206 for insulation, conversion from a signal suitable for transmission over twisted pair wire to digital signal, and from digital signal to twisted pair wire. Twisted pair link termination unit 205 that converts signals suitable for transmission, frame buffer unit 204 that temporarily holds communication signals, optical link termination unit 203 that exchanges information with OLT 1, and parallel signals to serial signals A serial / parallel conversion unit 202 that performs conversion into a serial signal and a parallel signal, and an optical / electrical conversion unit 201 that performs conversion from an optical signal into an electrical signal and conversion from an electrical signal into an optical signal. .
Further, it includes an optical output permission / prohibition signal 208, an optical output permission / prohibition function execution unit 209, a data processing unit 210, and a control unit 207.

Here, the optical output permission / prohibition signal 208 is a signal output from the optical link termination unit 203 and input to the optical output permission / prohibition function execution unit 209. When transmitting a frame, the optical output permission polarity and the frame are transmitted. If not, the light output polarity is prohibited. The optical output permission / prohibition function execution unit 209 exists in the optical / electrical conversion unit 201. When the optical output permission / prohibition signal 208 has the polarity of optical output permission, the serial / parallel conversion unit 202 changes to the optical / electrical conversion unit. The electrical signal input to 201 is converted into an optical signal, which is output from the optical / electrical conversion unit 201 to the optical coupler 3. When the optical output permission / prohibition signal 208 has a polarity for prohibiting optical output, the optical / electrical conversion unit Nothing is output from 201 to the optical coupler 3.
Further, the data processing unit 210 normally inputs the signal output from the optical link termination unit 203 to the serial / parallel conversion unit 202, and when the light emission from the ONU 2 should be suppressed, zero is input to the serial / parallel conversion unit 202. input. The control unit 207 collects information from each part and controls the light emitting diode lamp.
FIG. 5 shows the internal detailed configuration of the ONU 2A, but other ONUs have the same internal configuration.

  Here, the normal downlink frame transfer operation, the normal uplink frame transfer operation in the GE-PON system of the first embodiment, and the operation in the GE-PON system including the abnormality to be solved by the present invention are in this order. 6 will be described along the operation flowchart of the OLT 1 in FIG. 6 and the operation flowchart of the ONU 2 in FIG.

Here, the method for detecting the ONU 2 in which the optical output prohibition function is not functioning is the execution of S101 to S108 in the flowchart shown in FIG. 6, and the method for eliminating the state where other ONUs 2 cannot communicate is shown in FIG. This is an execution from steps S109 to S115 of the flowchart shown in FIG. 7 and steps S201 to S206 of the flowchart shown in FIG.
S101 to S108 in FIG. 6 are a flow from detecting the ONU 2 in which the optical output prohibition function is not functioning to notifying the network administrator of the abnormality, and S109 is for eliminating the state where other ONUs 2 cannot communicate. This is a flow for instructing the ONU 2 from which the light output prohibition function is not functioning to stop light emission from the OLT 1.

Further, FIG. 7 is a flow in which the ONU 2 that receives an instruction from the OLT 1 executes the suppression of the light emission, and notifies the network administrator that the state where the other ONUs 2 cannot communicate due to the suppression of the light emission has been solved. The flow for this is steps S110 to S115 in FIG.
Before explaining how the problems are solved by these flows, the means for detecting the ONU 2 in which the optical output prohibition function is not functioning is taken before the flow is reached. Therefore, first, the previous stage will be described.

  In order to detect the ONU 2 in which the optical output prohibiting function is not functioning, in the first embodiment, first, the phenomenon that there is an ONU 2 in which the optical output prohibiting function is not functioning is decomposed into several simple phenomena. By detecting these simple phenomena, the objective of detecting an ONU in which the optical output inhibition function is not functioning is achieved.

Described below is the decomposition of the phenomenon that there is an ONU 2 in which the optical output prohibition function does not function into a more specific and simple phenomenon.
As described above, when there is an ONU 2 in which the optical output prohibition function does not function, the following phenomena 1 and 2 are caused. Hereinafter, the ONU 2 in which the optical output prohibition function is not functioning is abbreviated as an abnormal ONU.

Phenomenon 1: An idle pattern optical signal continues to be transmitted from the abnormal ONU to the optical coupler 3 in a time slot other than the transmission occasion of the abnormal ONU.
Phenomenon 2: Logical links to ONUs other than abnormal ONUs have been resolved.

  As a result of the phenomenon 1, in the GE-PON system including the abnormal ONU, an idle pattern having a longer duration is observed in the optical coupler 3 than in the normal GE-PON system. In addition to the optical coupler 3, an idle pattern having a long duration can be similarly observed in the optical / electrical conversion unit 101, the serial / parallel conversion unit 102, and the optical link termination unit 103 in the OLT.

  Here, detection of an idle pattern having a longer duration than that in the normal state will be described. The maximum value of the idle pattern duration in a normal GE-PON system (named Tnormal) is expressed by (Equation 1) when referring to the IEEE 802.3ah standard, which is a standard of GE-PON.

(Formula 1)
Tnormal
= Toff (max) + Ton (max) + Treceiver_setting (max) + Tcdr (max) + Tcode_group_align (max)
Here, Toff (max) is the maximum value of the laser off time,
Ton (max) is the maximum value of the laser on time,
Treceiver_setting (max) is the maximum value of receiver stabilization time,
Tcdr (max) is the maximum value of CDR (clock and data recovery) lock time,
Tcode_group_align (max) represents the maximum code group alignment time.

Tnormal is 1.856 μs (μs = microseconds). The reason why the laser off time Toff is included in Tnormal is because the case where there is an overlap between the end of the frame sequence transmitted from the ONU and the start of the frame sequence transmitted from another ONU is taken into consideration. It is.
Therefore, if the duration of the idle pattern counted at the observation point described above is longer than Tnormal (the maximum value of the idle pattern duration in a normal GE-PON system) shown in (Equation 1), an abnormality has occurred. Can be detected.

To further summarize the decomposition of the phenomenon that the optical output prohibition function does not function into a simpler phenomenon, the optical output prohibition function functions by detecting both of the following phenomena 1 'and 2' It is possible to detect a phenomenon that there is an ONU that has not been performed.
Phenomenon 1 ′: In the serial / parallel converter 102, an idle pattern having a longer duration than normal is observed.
Phenomenon 2 ': Only one logical link has been established.

In the present invention, an idle pattern having a longer duration than normal due to phenomenon 1 ′ is detected in steps S101 to S105 shown in the flowchart of FIG. 6, and only one logical link due to phenomenon 2 ′ is established. Is detected in step S106.
In FIG. 6, I counter is an abbreviation for idle pattern duration counter, and R counter is an abbreviation for recovery time counter.

Each step will be described. Step S101 indicates an OLT activation and initialization step.
The steps from S102 to S105 are steps for counting the duration of the upstream idle pattern observed by the serial / parallel converter 102 in the OLT. S102 indicates that the idle pattern duration counter is reset to 0, and S103 determines whether or not an idle pattern is observed in the upstream direction of the serial / parallel converter 102 in the OLT. Yes.

If the observed pattern is an idle pattern, the idle pattern duration counter is incremented in step S104. If not, the idle pattern duration counter is reset to 0 in step S102.
In step S105, it is determined whether or not the idle pattern duration has exceeded a normal range. The normal range indicates that it is equal to or less than the maximum value of the idle pattern duration in a normal GE-PON system. When the normal range is exceeded, steps S106 and S110 are executed. If it does not exceed the normal range, the process returns to step S103, and the counting of the idle pattern duration is continued.

Step S106 determines whether or not only one logical link has been established. The logical link indicates a logical connection between the OLT and the ONU.
In step S107, it is determined whether an alarm has already been output. The alarm will be described below.

The alarm output in step S108 is intended to notify the network administrator that an abnormality has occurred. The abnormality to be notified here is an abnormality that all other ONUs cannot communicate due to the existence of an ONU in which the optical output prohibition function is not functioning.
Examples of alarms, that is, means for notifying abnormality include a light-emitting diode lamp and an SNMP (Simple Network Management Protocol) trap.
The light emitting diode lamp is used to make the network administrator visually recognize an abnormality by turning on / off / flashing, and the SNMP trap is used to transmit information that an abnormality has occurred to the network administrator via the network.
SNMP is a protocol for network management and is defined in RFC1157. The SNMP trap is an SNMP trap protocol data unit (trap-protocol data unit), and has a function of notifying the SNMP manager from the SNMP agent that the state of the monitoring target has changed.

  As described above, steps S101 to S108 up to this point are methods for detecting an ONU that does not function as a light output prohibiting function, and thus there is a problem of detecting an ONU 2 that does not function as a light output prohibiting function. It has been resolved. The steps after step S109 and the flowchart of ONU 2 shown in FIG. 7 are methods for eliminating the state where other ONUs 2 cannot communicate.

Here, step S109 indicates that an ONU that does not function the light output prohibiting function is instructed to suppress light emission.
The light emission suppression instruction is performed using an OAM protocol data unit (OAMPDU: Operations, Administration, and Maintenance Protocol Data Unit).
The OAM protocol data unit is a method for instructing the optical subscriber unit (ONU) 2 from the intra-station device (OLT) 1 and is transmitted from the OLT 1 to the ONU 2 with a mechanism similar to that in the case of transmitting a downlink frame. . The OAM protocol data unit can be transmitted to all ONUs 2, can be transmitted to one logical link ID, and can be transmitted to all logical link IDs except one logical link ID.

  Here, it is confirmed in step S106 that only one logical link has been established, and the only established logical link is the ONU 2 that does not function as an optical output prohibition function. Since it is a logical link, an OAM protocol data unit that gives the logical link ID and instructs the suppression of light emission is transmitted. By doing so, it is possible to instruct the ONU that does not function the light output prohibition function to suppress light emission.

  In steps S110 to S115, it is determined whether or not the abnormality has been eliminated. This abnormality also indicates an abnormality in which all other ONUs cannot communicate due to the existence of an ONU that does not function as an optical output prohibition function. A recovery time counter is provided to determine whether or not the abnormality has been resolved, and counts the time during which there is no abnormality in the idle pattern duration. If there is no abnormality in the idle pattern duration for a sufficient period of time, an alarm is issued. It is the operation of stopping.

  In step S110, an instruction to reset the recovery time counter to 0 is issued so that the recovery time counter does not exceed the predetermined value while the duration of the idle pattern exceeds the normal range. If the idle pattern duration continues to be in the normal range, the recovery time counter continues counting up and exceeds the predetermined value.

  In step S111, the recovery time counter is reset to 0 and started. In step S112, the recovery time counter is counted up. In step S113, it is determined whether the recovery time counter is instructed in step S110. If so, the recovery time counter is reset to 0 in step S111, and if a reset instruction is not issued, the process proceeds to step S114.

In step S114, it is determined whether or not the recovery time counter exceeds a predetermined value. If it does not exceed the predetermined value, the process returns to step S112 to count up the recovery time counter. If the predetermined value is exceeded, the alarm is stopped in step S115. The stop of the alarm is assumed to return the content expressed by means such as a light-emitting diode lamp or an SNMP trap in step S108 to a normal state.
For example, if the light-emitting diode lamp is turned on in step S108, the light-emitting diode lamp is turned off in step S115. If the SNMP trap that an abnormality has occurred is raised in step S108, step S115 is performed. Then, an SNMP trap that is recovered from the abnormal state is raised.

Next, a flowchart of the optical subscriber unit (ONU) 2 shown in FIG. 7 will be described.
The ONU 2 that has received the OAM protocol data unit instructing light emission suppression from the OLT 1 executes the light emission suppression, thereby eliminating the state in which other ONUs 2 cannot communicate. The ONU 2 continues normal operation until receiving an OAM instructing light emission suppression in step S203, and when receiving an OAM protocol data unit instructing light emission suppression in step S203, turns on the light emitting diode lamp in step S204. Alarm output. The intention of the alarm output is to notify the user that an abnormality has occurred in the ONU 2.

After outputting an alarm in step S204, light emission suppression is executed in step S205, and the process ends in step S206. Since this abnormality is caused by a failure, the ONU 2 is terminated with light emission suppressed, and no means for the ONU 2 to automatically recover is provided.
Note that the method of returning from the state in which the ONU 2 suppresses the light emission is to turn on the power of the ONU 2 again. It is added that even if the abnormal ONU 2 is turned on again without being repaired and can emit light again, the light emission can be suppressed again by the flow of FIGS. .

When the light emission is suppressed, idle pattern transmission from the abnormal ONU is eliminated, so that the GE-PON system returns to a normal state and another ONU 2 can communicate.
In addition, since an idle pattern having a duration exceeding the normal range is not observed, the network management indicates that the alarm is stopped by the flow of steps S110 to S115 in FIG. 6 and the GE-PON system has returned to the normal state. Can know.
As described above, by executing steps S109 to S115 of the flowchart shown in FIG. 6 and the flowchart shown in FIG. 7, it is possible to solve the problem of eliminating the state where other ONUs 2 cannot communicate.

The operation of the GE-PON system has been described with reference to the flowcharts. Hereinafter, these operations will be described in order as operations of respective units of the apparatus.
First, the frame transfer operation of the GE-PON system at the normal time will be described.
Since the frame transfer operation of the entire GE-PON system has already been described with reference to FIGS. 1 to 4, the operation in the OLT 1 and the ONU 2 will be described based on FIG. 5.

As an outline of the downlink frame transfer operation, the intra-station device (OLT) 1 transfers the frame transmitted from the connection device 4D in FIG. 5 and inputs it to the optical coupler 3, and the optical coupler 3 branches the light. A frame is broadcast to each optical subscriber unit (ONU) 2, and each ONU 2 forwards the frame to the connected device if it is destined for its own ONU, and discards it if it is not destined for its own ONU.
Although three ONUs 2 are shown in FIG. 5, the operation is the same regardless of which ONU 2 is taken.

The details of the downlink frame transfer operation will be described with reference to FIG. 5. The frame transmitted from the connection device 4D is input to the twisted pair link termination unit 105 via the transformer 106 in the OLT.
The twisted pair link termination unit 105 outputs the input information (frame) as it is without changing the information to be carried, but converts the signal form from a signal suitable for transmission over the twisted pair to a digital signal. To do. By using a digital signal, it becomes a signal that is easy to handle in an electronic circuit. The frame output from the twisted pair link termination unit 105 is stored in the frame buffer unit 104.

In addition to the frame transmitted from the connected device 4D and stored in the frame buffer unit 104, the optical link termination unit 103 is not limited to the MPC protocol data unit (Multi-Point Control Protocol Data Unit) or the OAM protocol data unit (Operations, Administration). , And Maintenance Protocol Data Unit) to the serial / parallel converter 102.
The MPC protocol data unit is a control frame exchanged between the optical link terminator 103 in the OLT 1 and the optical link terminator 203 in the ONU 2 and is used for a transmission time instruction from the OLT to the ONU. The OAM protocol data unit is a control frame exchanged between the optical link termination unit 103 in the OLT 1 and the optical link termination unit 203 in the ONU 2 and is used for notifying an abnormality.

  Only one frame, MPC protocol data unit or OAM protocol data unit can be output from the optical link termination unit 103 to the serial / parallel conversion unit 102 one by one in order, and the rules defined in the IEEE 802.3ah standard. Among these, the MPC protocol data unit is transmitted with the highest priority, and then the OAM protocol data unit is prioritized. Therefore, while the MPC protocol data unit or the OAM protocol data unit is transmitted from the optical link termination unit 103, The frame waits in the frame buffer unit 104, and when the transmission of the MPC protocol data unit or the OAM protocol data unit ends, the frame is taken out from the frame buffer unit 104 and the optical link termination unit 103 Is output.

  The optical link termination unit 103 assigns a logical link ID to the frame, MPC protocol data unit, or OAM protocol data unit, and outputs it to the serial / parallel conversion unit 102. The logical link ID is information for making the ONU recognize which ONU the frame, MPC protocol data unit, or OAM protocol data unit is addressed to.

  The frame or MPC protocol data unit or OAM protocol data unit input to the serial / parallel converter 102 is converted from a parallel signal to a serial signal and output to the optical / electrical converter 101. The frame or MPC protocol data unit or OAM protocol data unit input to the optical / electrical converter 101 is converted from an electrical signal to an optical signal and output to the optical coupler 3. It is supplemented that the idle pattern duration counter 108 and the recovery time counter 109 in the OLT are not involved in the downlink frame transfer operation.

  The frame or MPC protocol data unit or OAM protocol data unit output from the optical coupler 3 is converted from an optical signal to an electrical signal by the optical / electrical conversion unit 201 in the ONU and output to the serial / parallel conversion unit 202. . The serial / parallel converter 202 converts the frame, MPC protocol data unit, or OAM protocol data unit from a serial signal to a parallel signal and outputs it to the optical link termination unit 203. The optical link termination unit 203 confirms the logical link ID of the input frame or MPC protocol data unit or OAM protocol data unit, and if it is determined not to be addressed to the own ONU, the frame or MPC protocol data unit or OAM protocol data unit is determined. Discard.

  If the logical link ID of the frame or MPC protocol data unit or OAM protocol data unit is addressed to its own ONU, if it is a frame, the logical link ID is removed and output to the frame buffer unit 204 to output the MPC protocol data unit or OAM protocol data. If it is a unit, an operation according to the contents of the MPC protocol data unit or the OAM protocol data unit is executed. Depending on the content, the control unit 207 is notified, and the control unit 207 is caused to execute an operation. The frame buffer unit 204 outputs the frame input from the optical link termination unit 203 to the twisted pair link termination unit 205. The twisted pair wire link termination unit 205 converts the frame from a digital signal to a signal suitable for transmission through the twisted pair wire, and outputs the frame to the connection device 4A via the transformer 206.

  Subsequently, an uplink frame transfer operation will be described. As an outline of the uplink frame transfer operation, a frame transmitted from the connection device 4A in FIG. 5 is transferred by the optical subscriber unit (ONU) 2A, input to the optical coupler 3, and output from the optical coupler 3. Is transferred by the in-station device (OLT) 1 of FIG. 4 and transmitted to the connection device 4D. The operation of other ONUs is the same as that of ONU 2A.

  Details of the uplink frame transfer operation will be described by dividing the operation up to the ONU and the operation in the OLT. First, the operation in the ONU will be described. The frame transmitted from the connection device 4A is input to the twisted pair link termination unit 205 via the transformer 206. The twisted pair link termination unit 205 converts the frame from a signal suitable for transmission over the twisted pair to a digital signal.

  The frame output from the twisted pair link termination unit 205 is stored in the frame buffer unit 204. The frame stored in the frame buffer unit 204 waits in the frame buffer unit 204 until an instruction from the optical link termination unit 203 is received. The optical link termination unit 203 receives an instruction regarding the time when the ONU 2A starts transmitting the frame sequence and the time for continuing the transmission in the downlink MPC protocol data unit transmitted from the OLT 1. Since a plurality of frames can be transmitted within one transmission opportunity, it is supplemented that it is expressed as a frame sequence.

  The optical link termination unit 203 outputs an idle pattern during a time period that is not a transmission opportunity of the ONU 2A. When the data processing unit 210 does not receive an OAM protocol data unit for instructing suppression of light emission from the OLT 1, the data processing unit 210 outputs the signal input from the optical link termination unit 203 to the serial / parallel conversion unit 202 as it is. The idle pattern input from the termination unit 203 is output to the serial / parallel conversion unit 202. The data processing unit 210 also gives the optical output permission / prohibition signal 208 the same amount of delay as that caused by passing the main signal through the data processing unit 210. This is a process for operating the optical output permission / prohibition signal 208 at an appropriate timing.

  The serial / parallel conversion unit 202 converts the idle pattern input from the data processing unit 210 from a parallel signal to a serial signal, and outputs it to the optical output permission / prohibition function execution unit 209. Since the optical output permission / prohibition signal 208 is output from the optical link termination unit 203 with the polarity of “optical output prohibition” in the time zone that is not the transmission opportunity of the ONU 2A, the optical output permission / prohibition function execution unit 209 outputs the optical coupler. Nothing is output to 3.

When it is time to start transmitting the frame sequence, the optical link termination unit 203 sets the optical output permission / prohibition signal 208 to the polarity of “optical output permission” and sets the OLT reception synchronization time defined in the IEEE 802.3ah standard (Equation 2). The idle pattern is output during the period.
It is supplemented that the OLT reception synchronization time of (Equation 2) is shorter than the maximum value Tnormal of the normal idle pattern duration shown in (Equation 1).

(Formula 2)
OLT reception synchronization time =
Ton + Treceiver_setting + Tcdr + Tcode_group_align
here,
Ton is the laser on time,
Treceiver_settling is the receiver stabilization time,
Tcdr is a CDR (clock and data recovery) lock time,
Tcode_group_align represents a code group alignment time.

The idle pattern during the period of this (Equation 2) OLT reception synchronization time is that the optical output permission / prohibition signal 208 has the polarity of “optical output permission”, so the data processing unit 210, the serial / parallel conversion unit 202, the optical output permission / Output to the optical coupler 3 through the prohibition function execution unit 209.
After transmitting the idle pattern of the period of (Equation 2), the optical link termination unit 203 gives a logical link ID to the MPC protocol data unit, the OAM protocol data unit, or the frame that has been waiting in the frame buffer unit 204, The data is output to the data processing unit 210.

  Since the data processing unit 210 does not receive an OAM protocol data unit for instructing suppression of light emission from the OLT 1, the frame, MPC protocol data unit, or OAM protocol data unit input from the optical link termination unit 203 is directly converted into serial / parallel data. The serial / parallel conversion unit 202 converts the frame or MPC protocol data unit or OAM protocol data unit input from the data processing unit 210 from a parallel signal into a serial signal, and executes an optical output permission / inhibition function. Output to the unit 209. The optical output permission / prohibition function execution unit 209 changes the frame, MPC protocol data unit, or OAM protocol data unit from an electrical signal to an optical signal because the optical output permission / prohibition signal 208 has the polarity of “optical output permission”. The signal is converted and output to the optical coupler 3.

When outputting a plurality of frames within a single transmission opportunity, the optical link termination unit 203 transmits an idle pattern between the frames for a period called an IFG (Inter Frame Gap). It is supplemented that IFG is 0.096 μs (microseconds), which is shorter than Tnormal shown in (Equation 1).
Since the optical output enable / disable signal 208 remains “optical output enabled” even during the IFG period, the idle pattern during the IFG period includes the data processing unit 210, the serial / parallel converter 202, the optical output enable / disable The data is output to the optical coupler 3 via the prohibited function execution unit 209.

The optical link termination unit 203 determines that the transmission of the next frame cannot be completed within the transmission duration indicated by the OLT 1 in the previous MPC protocol data unit in the downstream direction, or the frame buffer When the transmission of all the frames waiting in the unit 204 is completed, the optical link termination unit 103 transmits an idle pattern for a period called a laser off time Toff, and sets the optical output permission / prohibition signal 208 to “optical output prohibited”. Make it polar. The laser off time Toff is smaller than the maximum value of the idle pattern duration in the normal state shown in (Equation 1).
When the optical output permission / prohibition signal 208 has the polarity of “optical output prohibition”, nothing is output from the optical output permission / prohibition function execution unit 209 to the optical coupler 3.

Next, an uplink frame transfer operation in the intra-station apparatus (OLT) will be described.
The following describes how each upstream signal output from the optical subscriber unit (ONU) 2 to the optical coupler 3 is processed in the OLT 1. The signal output from the ONU 2 to the optical coupler 3 includes an idle pattern of the OLT reception synchronization time represented by (Equation 2), an idle pattern called IFG transmitted between frames, MPC protocol data units, OAM protocol data units, and frames. The pattern is an idle pattern called Toff transmitted at the end of the ONU2A transmission opportunity.

FIG. 8 shows the state of these signals. The horizontal axis is time, which is input to the OLT 1 from the left side of the figure. The upper part is a signal observed in a normal GE-PON system, and the lower part is a signal observed in a GE-PON system including an abnormality. A signal enclosed by a double square is an idle pattern, and a signal enclosed by a single square and no signal are non-idle patterns.
The idle pattern in the OLT reception synchronization time period expressed by (Equation 2) output from the optical coupler 3 is converted from an optical signal to an electrical signal by the optical / electrical converter 101 and input to the serial / parallel converter 102. Is done. The serial / parallel converter 102 notifies the idle pattern duration counter 108 that an idle pattern has been detected.

  This corresponds to the operation of step S103 of the flowchart according to the present invention in FIG. The idle pattern duration counter 108 counts up the idle pattern duration counter according to step S104. During the period of the OLT reception synchronization time represented by (Equation 2), the serial / parallel converter 102 continues to detect the idle pattern and the idle pattern duration counter continues to count up, but the OLT reception synchronization represented by (Equation 2). In the time period, the normal range in step S105, that is, the maximum value of the normal idle pattern duration shown in (Equation 1) is not reached.

  The serial / parallel conversion unit 102 converts the idle pattern during the OLT reception synchronization time period of (Equation 2) from a serial signal to a parallel signal and outputs the converted signal to the optical link termination unit 103. The optical link termination unit receives an idle pattern during the OLT reception synchronization time of (Equation 2), but does not transfer it to the frame buffer unit 104.

  After the idle pattern of the OLT reception synchronization time period of (Equation 2) is input from the optical coupler 3 to the optical / electrical converter 101, a frame, MPC protocol data unit, or OAM protocol data unit is input. The optical / electric conversion unit 101 converts the optical signal into an electric signal, and the serial / parallel conversion unit 102 converts the serial signal into a parallel signal. Since the frame, MPC protocol data unit or OAM protocol data unit is not an idle pattern, the serial / parallel converter 102 informs the idle pattern duration counter 108 that the idle pattern is not detected, and the idle pattern duration time. The counter is reset to 0 by S102.

The serial / parallel converter 102 converts the frame, MPC protocol data unit, or OAM protocol data unit from a serial signal to a parallel signal and outputs it to the optical link termination unit 103.
The optical link termination unit 103 removes the logical link ID of the frame and outputs it to the frame buffer unit 104. If the frame is an MPC protocol data unit or an OAM protocol data unit, the optical link termination unit 103 operates according to the contents, and if necessary, Transfer to the control unit 107.

The frame input to the frame buffer unit 104 is output to the twisted pair link termination unit 105. The twisted pair link termination unit 105 converts the frame from a digital signal to a signal suitable for transmission over the twisted pair line, and converts the transformer 106. To the connected device 4D.
Even when an idle pattern of the IFG period is input from the optical coupler 3 to the optical / electrical converter 101 and when an idle pattern of the laser off time Toff is input, the idle pattern of the OLT reception synchronization time of (Equation 2) is The operation is the same as when input, and the idle pattern duration counter does not exceed the normal range of S105.

The frame transfer operation in the normal GE-PON system has been described above. Next, the operation when there is an optical subscriber unit (ONU) in which the optical output prohibition function does not function will be described.
In the GE-PON system as shown in FIG. 1, it is assumed that the ONU 2A is an ONU in which the optical output prohibition function does not function and the ONUs 2B and 2C are normal ONUs.

  The operation of the ONU 2A having an abnormality that the optical output prohibition function does not function will be described. The optical link termination unit 203 of the ONU 2A has an OLT reception synchronization time of (Equation 2) at the transmission opportunity of the ONU 2A as in the normal case. Send idle pattern, followed by frame or MPC protocol data unit or OAM protocol data unit, send idle pattern of IFG period between frames, send last frame in transmission opportunity Thereafter, an idle pattern having a laser off time Toff is transmitted. When it is not an ONU 2A transmission opportunity, an idle pattern is transmitted. Since the data processing unit 210 has not yet received an instruction to suppress the light emission, the signal received from the optical link termination unit 203 is output to the serial / parallel conversion unit 202 as it is, and the serial / parallel conversion unit 202 converts these signals from the parallel signal. The data is converted into a serial signal and output to the optical output permission / prohibition function execution unit 209.

Since the optical output prohibition function does not function, the optical output permission / prohibition function execution unit 209 converts the received signal from an electrical signal to an optical signal and outputs it to the optical coupler 3.
That is, even when an abnormality occurs, a signal output from the optical link termination unit 203 of the ONU 2A is output to the optical coupler 3 as it is until it receives an instruction to suppress light emission from the local station (OLT) 1. The difference from the normal time is that the idle pattern continues to be output except for the transmission opportunity of the ONU 2A. The idle pattern after Toff at the time of abnormality (lower stage) in FIG. 8 corresponds to this.

Moving to the description of the operation in the OLT 1, the idle pattern of the OLT reception synchronization time of (Equation 2), followed by the frame or MPC protocol data unit or the OAM protocol data unit, the idle pattern of the IFG period between frames, The idle pattern of the laser off time Toff is processed in the OLT as in the normal state.
After the idle pattern of the laser off time Toff is output, the ONU 2A transmission opportunity ends, so nothing is output from the ONU 2A under normal conditions, but the ONU 2A optical output prohibition function is not functioning. An idle pattern is output.

  Optical signals have been sent from other ONUs connected to the optical coupler 3 (ONUs 2B and 2C, referring to FIG. 3). Therefore, the optical signal output from the ONU 2B and ONU 2C to the optical coupler 3 is mixed by the optical coupler 3 and converted from the optical signal to the electrical signal by the optical / electrical conversion unit 101. Even if the conversion unit 102 converts the signals into parallel signals, the optical link termination unit 103 cannot read the information sent by the ONU 2B or ONU 2C.

Since the optical link termination unit 103 cancels the logical link for the ONU that has not received the MPC protocol data unit for a period called “mpcp_timer”, the ONU 2B and the ONU 2C lose the logical link ID. Since the ONU 2A sends the MPC protocol data unit within the transmission opportunity of the ONU 2A, the logical link of the ONU 2A is maintained.
After the logical link is canceled, the ONUs 2B and 2C do not output anything to the optical coupler 3 except for a period called a discovery window time.
Therefore, the idle pattern having a long duration exceeding the maximum value of the idle pattern duration at the normal time shown in (Equation 1) from when the ONU 2A finishes transmitting the frame in the frame buffer unit 204 until the discovery window time starts. Is input from the optical coupler 3 to the OLT 1.

An idle pattern having a long duration is converted from an optical signal to an electrical signal by the optical / electrical converter 101 and input to the serial / parallel converter 102.
The serial / parallel converter 102 detects an idle pattern and notifies the idle pattern duration counter 108. Also, the idle pattern is converted from a serial signal to a parallel signal and output to the optical link termination unit 103.
The idle pattern duration counter 108 continues to count up the idle pattern duration counter by detecting the idle pattern, and the count value is in a normal range, that is, the maximum value of the idle pattern duration at normal time shown in (Equation 1). Exceed.

  When the count value exceeds the normal range, the idle pattern duration counter 108 resets the count value of the recovery time counter 109 to 0 while notifying the control unit 107 with an interrupt signal. This operation corresponds to S110 in the flowchart of FIG. Although the operation of the recovery time counter 109 has not been described so far, the recovery time counter continues to count up until a predetermined value is exceeded, and when the predetermined value is exceeded, a signal to stop the alarm is sent to the control unit 107. Output. The default value is a value in the range of several tens of milliseconds to several seconds. The intention is to stop the alarm when it is confirmed that the idle pattern duration does not exceed the normal range even after monitoring for a certain period of time. Even if the control unit 107 receives an alarm stop signal from the recovery time counter 109, it does nothing except in a situation where an alarm is output.

The control unit 107 checks whether only one logical link has been established when the interrupt signal rises from the idle pattern duration counter 108 (idle duration counting function).
This operation corresponds to S106 in the flowchart of FIG. If a plurality of logical links are still established, it is premature to perform the subsequent flow operation, the idle pattern duration counter is reset to 0, and the idle pattern duration is counted again.
The situation where a plurality of logical links are established in S106 is that the mcp_timer for the logical link between the OLT 1 and any other ONU has not expired, and any ONU still maintains the logical link. Caused by. If it waits until the mpcp_timer of another ONU expires, it becomes easy to identify an abnormal ONU. Therefore, the process does not proceed to the flow S107 until only one logical link is established.

  Until the abnormality is resolved by the flow after S107, a time zone in which an idle pattern having a duration exceeding the normal range is observed occasionally appears. When the idle pattern duration counter exceeds the normal range, if the logical link of the ONU other than the abnormal ONU has been resolved, the control unit 107 checks whether an alarm has already been output and outputs an alarm. . As described above, the alarm output includes lighting of a light emitting diode lamp, an SNMP trap, and the like.

  The operation of the recovery time counter 109 after the alarm is output will be described. The idle pattern duration counter sometimes exceeds the normal range from when the alarm is output until the light emission is suppressed by the abnormal ONU, and the recovery time counter 109 Therefore, the recovery time counter does not reach the predetermined value, and therefore the alarm stop instruction is not issued from the recovery time counter 109 to the control unit 107.

  After outputting the alarm, the control unit 107 creates an OAM protocol data unit for suppressing the ONU 2A from emitting light. The OAM protocol data unit for suppressing the ONU 2A emission conforms to the configuration of the Organization Specific OAMPDU of the IEEE 802.3ah standard, which is a GE-PON standard. The Organization Specific OAMPDU is a number that uses the value 0xFE for the OAMPDU code field, and if the OAM PDU data field uses OUI (Organizationally Unique Identifier) for the first 3 octets, the rest of the data field It may be defined as follows.

  Therefore, a light emission suppression instruction field is defined in the remaining data field of the Organization Specific OAM protocol data unit. The ONU that received the OAM protocol data unit in which 1 is stored in the light emission suppression instruction field executes the light emission suppression and receives the OAM protocol data unit in which 0 is stored in the light emission suppression field. The ONU will continue normal operation. Hereinafter, the Organization Specific OAM protocol data unit in which 1 is stored in the light emission suppression field is referred to as a light emission suppression OAM protocol data unit.

The control unit 107 sends the light emission suppression OAM protocol data unit and the logical link ID to be assigned to the light emission suppression OAM protocol data unit to the optical link termination unit 103. The logical link ID to be assigned to the light emission suppression OAM protocol data unit is the logical link ID of the only logical link that has been established when it is confirmed that only one logical link has been established.
The optical link termination unit 103 assigns a logical link ID to be assigned to the light emission inhibition OAM protocol data unit to the light emission inhibition OAM protocol data unit, and outputs the logical link ID to the downstream direction, that is, the serial / parallel conversion unit 102. The serial / parallel converter 102 converts the light emission suppression OAM protocol data unit from a parallel signal to a serial signal and outputs it to the optical / electrical conversion unit 101. The optical / electrical conversion unit 101 converts the light emission suppression OAM protocol data unit from the electrical signal. It is converted into an optical signal and output to the optical coupler 3.

  The light emission suppression OAM protocol data unit is distributed from the optical coupler 3 to each ONU, and within each ONU, the light emission suppression OAM protocol data unit is converted from an optical signal to an electrical signal by the optical / electric conversion unit 201, and serial / parallel conversion is performed. The unit 202 converts the serial signal into a parallel signal and outputs it to the optical link termination unit 203. Since the ONU 2B and ONU 2C do not have a logical link ID, the Organization Specific OAM protocol data unit, that is, the light emission suppression OAM protocol data unit is discarded. The optical link termination unit 203 of the ONU 2A receives the light emission suppression OAM protocol data unit having the logical link ID addressed to the own ONU and transfers it to the control unit 207.

  The control unit 207 of the ONU 2A analyzes the contents of the light emission suppression OAM protocol data unit, confirms that the light emission suppression instruction field is 1, outputs a warning, and then instructs the data processing unit 210 to suppress light emission. To do. The alarm output here is lighting of a light emitting diode lamp or the like. The intention is to turn on a light-emitting diode lamp named “alarm” or the like to visually recognize that there is an abnormality in the ONU.

The data processing unit 210 that has received the light emission suppression instruction from the control unit 207 continues to output zero instead of the signal input from the optical link termination unit 203 to the serial / parallel conversion unit 202.
The serial / parallel conversion unit 202 converts the zero sequence input from the data processing unit 210 from a parallel signal to a serial signal, and outputs the serial signal to the optical / electrical conversion unit 201. The optical / electrical converter 201 does not emit light because 0 is input. Accordingly, no optical signal is output from the ONU 2A to the optical coupler 3 after the light emission is suppressed.
When there is no idle pattern output from the ONU 2A to the optical coupler 3, the ONU 2B and ONU 2C can transmit the uplink MPC protocol data unit at a predetermined time, and the logical link between the ONU 2B and the ONU 2C again Establish.

Since no optical signal is output from the ONU 2A that has output an idle pattern with a long duration, the idle pattern duration counter is within the normal range for the idle pattern detected by the serial / parallel converter 102 in the OLT 1. The longer the value is exceeded, the longer the duration does not continue, and the idle pattern duration counter does not exceed the normal range.
When the idle pattern duration counter does not exceed the normal range, the recovery time counter continues counting up and exceeds the predetermined value. When the recovery time counter exceeds a predetermined value, the recovery time counter 109 outputs a signal to stop the alarm to the control unit 107, and the control unit 107 stops the alarm. Stopping the alarm includes turning off the light-emitting diode lamp, which means an abnormality, and raising an SNMP trap indicating that the abnormality has been recovered.
As described so far, according to the first embodiment, it is possible for a normal other ONU to resume communication, and that the abnormal state has been resolved based on the SNMP trap history or the like. Can be informed.

Next, another embodiment of the present invention will be described.
FIG. 9 shows a block diagram of the optical subscriber unit (ONU) 2 according to the second embodiment of the present invention.
In this embodiment, a circuit (power supply control unit 301) for controlling power supply to the optical / electrical conversion unit 211 is provided in the ONU in order to execute the light emission suppression shown in S205 of the flowchart of the ONU 2 in FIG. . At this time, the data processing unit 210 shown in FIG. 5 is not necessary.
The function of the power supply control unit 301 to the optical / electrical converter 211 is to supply power to the optical / electrical converter 211 when light emission is not suppressed, and not to supply power to the optical / electrical converter 211 when light emission is suppressed. That's it.
The operation of the optical / electrical converter 211 when no power is supplied is an operation in which nothing is output from the optical / electrical converter 211 to the optical coupler 31 regardless of the signal input from the serial / parallel converter 212. It becomes. Further, even if an optical signal is received from the optical coupler 31, nothing is output to the serial / parallel converter 212.
Note that the power supply control unit 301 serves as a quenching unit in the second embodiment.

A third embodiment of the present invention will be described below. (Since this is a slight modification from FIG. 9, the illustration is omitted.)
This is a modification of the first embodiment of the invention, in which the power supply control unit 301 to the optical / electrical converter 211 in FIG. 9 is changed to supply power to the transmission circuit in the optical / electrical converter 211. The supply control unit.
The difference from the second embodiment of the present invention is that the power supply to the transmission circuit in the optical / electrical conversion unit 211 is not stopped when the light emission is suppressed, but the power supply to the entire optical / electrical conversion unit 201 is not stopped. The supply will be stopped. That is, in this embodiment, power supply to the receiving circuit in the optical / electrical conversion unit 211 is not controlled, and power is always supplied. The function of the power supply control unit to the transmission circuit in the optical / electrical conversion unit 211 is to supply power to the transmission circuit in the optical / electrical conversion unit 211 when light emission is not suppressed and to the optical / electrical conversion unit when light emission is suppressed. No power is supplied to the transmission circuit 211.
The operation of the optical / electrical conversion unit 211 when power is not supplied to the transmission circuit in the optical / electrical conversion unit 201 is performed from the optical / electrical conversion unit 211 to the optical coupler regardless of the signal input from the serial / parallel conversion unit 212. No operation is output to 31.
The changed power supply control unit 301 functions as a quenching unit in the third embodiment.

As still another embodiment of the present invention, examples in which threshold values for determining that the idle pattern duration time is not normal are changed from the Tnormal shown in the first embodiment are listed below.
In the fourth embodiment of the present invention, as a threshold for determining that the idle pattern duration time is not normal, a margin slightly longer than Tnormal is set as a threshold in consideration of a margin in Tnormal shown in (Expression 1). It is.

  In the fifth embodiment of the present invention, Toff (max), Ton (max), Treseverer_setting (max), Tcdr (shown in (Equation 1)) are used as thresholds for determining that the idle pattern duration is not normal. max) and Tcode_group_align (max) are changed to values in the actual system. These max values shown in (Equation 1) are the maximum values allowed in the IEEE 802.3ah standard, and are designed using values less than these maximum values in an actual GE-PON system. By adopting the value in the actual system, the threshold becomes shorter than the value of (Equation 1).

  In the sixth embodiment of the present invention, the threshold for determining that the idle pattern duration is not normal is a value that allows for a margin in the threshold shown in the fifth embodiment.

  In the seventh embodiment of the present invention, a value obtained by subtracting Toff (max) from the value of (Expression 1) is used as a threshold for determining that the idle pattern duration is not normal.

  In the eighth embodiment of the present invention, Toff (max) or actually used from the threshold in the fifth embodiment of the present invention as a threshold for determining that the idle pattern duration is not normal. A value obtained by subtracting Toff.

In the ninth embodiment of the present invention, as a threshold for determining that the idle pattern duration is not normal, a value allowing for a margin in the IFG is used.
In the ninth embodiment, one or more of Toff (max), Ton (max), Treceiver_setting (max), Tcdr (max), and Tcode_group_align (max) shown in (Equation 1) in the actual system are used. When the values are changed, it is assumed that the sum of these values is less than IFG, and the maximum value of the idle pattern duration in a normal GE-PON system is IFG.

In the above description, the GE-PON system of the present invention and the abnormal light emission suppression method used in the GE-PON system have been described. However, the execution contents of each process of the above abnormal light emission suppression method are programmed and stored in the computer of the in-station device (OLT). You may comprise so that it may be performed.
As a result, the problem that all other ONUs cannot communicate due to the failure of the optical output prohibition function of one optical subscriber unit (ONU) can be solved by the computer.

Since the present invention is configured as described above, it is possible to obtain the following superior effects as described below.
The first effect is that the severe trouble that only one abnormal ONU is in the GE-PON system and all other dozens of other ONUs cannot communicate is automatically resolved. Providing a means.
This realizes a series of operations from when the OTL detects an ONU in which the optical output prohibition function is not functioning to take countermeasures until the abnormality is resolved and the other ONUs are able to communicate. It depends on.

The second effect is that the present invention is realized without wasting a band between the optical link termination unit in the OLT and the optical link termination unit in the ONU.
This is because in the GE-PON system that implements the present invention, no traffic for realizing the present invention is generated at all times, both at normal time and after the abnormality is resolved. Further, in the first embodiment of the present invention, the data processing unit 210 is added, but it is supplemented that this does not lead to delay or waste of bandwidth. In the GE-PON system, since the OLT conventionally has a function of measuring the delay of each ONU and instructing the transmission time in consideration of the delay, the delay is compensated.

The third effect is that the present invention is realized at low cost.
This is because the optical / electrical conversion unit, which is an expensive part of the apparatus, and the optical link termination unit are not modified. The optical / electrical converter and the optical link terminal are particularly expensive parts in the GE-PON system. If these are modified, there will be special specifications, the distribution volume will not increase, and there is a possibility that the cost will be high. In the present invention, since these are not modified, it is possible to use commercially available parts (standard specifications) that are distributed in large quantities and have an appropriate price.

The fourth effect is that the ease of maintenance is improved.
The reason is that an abnormality is detected by OLT. If it is possible to grasp that an abnormality has occurred in the OLT, it becomes possible to notify the network administrator of the abnormality via the monitoring network without relying only on visual recognition by LED display. As a result, the network administrator having specialized knowledge can be informed of the abnormality, and therefore, an appropriate countermeasure regarding the failure ONU can be expected.

  The present invention can solve the problem that in the GE-PON system, all other ONUs cannot communicate due to the failure of the optical output prohibition function of one ONU, so the communication industry adopting the GE-PON system. The possibility of wide use is expected.

It is a block diagram which shows the basic composition of the GE-PON system concerning this invention. It is a chart which shows the transfer order of the downstream frame in the GE-PON system shown in FIG. 3 is a chart showing an uplink frame transfer order in the GE-PON system shown in FIG. 1. 3 is a chart showing a state of merging of upstream frames in an optical coupler in the GE-PON system shown in FIG. 1. It is a block diagram which shows the structure of 1st Embodiment of the GE-PON system of this invention. 6 is an operation flowchart of the intra-station apparatus of the first embodiment shown in FIG. 5. It is an operation | movement flowchart of the optical subscriber apparatus of 1st Embodiment shown in FIG. It is a time chart of the up direction signal observed in the serial / parallel conversion part of the intra-station apparatus of 1st Embodiment. It is a block diagram which shows the structure of the optical subscriber apparatus of 2nd Embodiment of the GE-PON system of this invention. It is a block diagram which shows the structure of the conventional GE-PON system.

Explanation of symbols

1 Intra-station equipment 2A, 2B, 2C Optical subscriber equipment 3 Optical coupler 103 Optical link termination (light emission stop command transmission means)
107 Control unit (optical subscriber unit abnormality detection means, light emission stop command transmission means, logical connection state detection function)
108 Idle pattern duration counter (Idle duration counting function)
210 Data processing section (quenching means, data processing means)
301 Power supply control unit (extinction means, optical / electrical conversion power supply control means)

Claims (11)

An intra-station device, a plurality of optical subscriber devices, an optical coupler provided between the two, an optical fiber line connecting them, an upstream signal from the optical subscriber device to the intra-station device, and In an optical subscriber communication system for communicating a downstream signal from an intra-station device to the optical subscriber device,
The intra-station device is an optical subscriber unit abnormality detecting means for detecting an abnormality of the optical subscriber unit,
A light emission stop command transmission means for transmitting a signal including a light emission stop command to stop light emission to the optical subscriber apparatus in which the optical subscriber apparatus abnormality detection means has detected an abnormality as the downlink signal;
The optical subscriber communication system is characterized in that the optical subscriber unit further comprises extinction means for stopping light emission of the own station based on a light emission stop command sent from the light emission stop command transmission means. In the optical subscriber communication system according to claim 1,
The optical subscriber unit anomaly detection means is an idle duration counting function that counts the duration of an idle pattern sent from the optical subscriber unit to the optical coupler during idling.
A logical connection state detection function for detecting a logical connection establishment state with the optical subscriber unit,
If the counting output of the idle duration counting function is longer than a prescribed value determined from the standard of the optical subscriber communication system and only one logical connection detected by the logical state detection means is established, the logical connection is currently established. An optical subscriber communication system, wherein an optical subscriber device is determined to be abnormal.   Each of the contents specified as the optical subscriber communication system according to claim 2 is regulated by a GE-PON (Gigabit Ethernet Passive Optical Network) system defined by the IEEE 802.3ah standard. Subscriber communication system.   The specified values shown in claim 2 are the maximum value of the laser off time of the GE-PON system, the maximum value of the laser on time, the maximum value of the receiver stabilization time, and the CDR lock defined in the IEEE 802.3ah standard. An optical subscriber communication system characterized by being a sum of a maximum value of time and a maximum value of code group alignment time. In the optical subscriber communication system according to any one of claims 1 to 4,
An optical subscriber communication system, wherein the extinction means is data processing means for replacing all numerical values of the upstream signal with 0. In the optical subscriber communication system according to any one of claims 1 to 4,
An optical subscriber communication system, wherein the extinction means is an optical / electrical conversion power supply control means for cutting off power supply to an optical / electrical conversion unit that converts the upstream signal from an electrical signal into an optical signal. In the optical subscriber communication system according to any one of claims 1 to 4,
An optical subscriber communication system, wherein the extinction means is transmission power supply control means for cutting off power supply to a transmission means in an optical / electrical conversion unit for converting the upstream signal from an electrical signal to an optical signal. A method for suppressing abnormal light emission of an optical subscriber unit in an optical subscriber communication system comprising an intra-station device and a plurality of optical subscriber units connected to the intra-station device via an optical fiber line including an optical coupler. And
An optical subscriber unit abnormality detection step for detecting an abnormality of the optical subscriber unit executed by the intra-station device;
Light emission stop command transmission step for transmitting a signal including a light emission stop command for stopping light emission to the optical subscriber device that has detected an abnormality in this optical subscriber unit abnormality detection step by downlink communication from the intra-station device to the optical subscriber device When,
A light extinction step of stopping the light emission of the local station based on the light emission stop command transmitted in the light emission stop command transmission step executed in the optical subscriber unit. An abnormal light emission suppression method for a subscriber unit. In the method for suppressing abnormal light emission of the optical subscriber unit in the optical subscriber communication system according to claim 8,
The optical subscriber unit anomaly detection step includes an idle duration counting step for counting the duration of an idle pattern sent from the optical subscriber unit during idling,
An idle duration comparison step of comparing the count value in the idle duration counting step with a specified value determined from the standard of the optical subscriber communication system;
A logical connection state detection step of detecting a logical connection establishment state with the optical subscriber unit,
When the count value in the idle duration comparison step is longer than the specified value and only one logical connection detected in the logical state detection step is established, the currently logically connected optical subscriber unit is abnormal. An abnormal light emission suppression method for an optical subscriber unit in an optical subscriber communication system, characterized in that: An abnormal light emission suppression program for an optical subscriber unit in an optical subscriber communication system including an intra-station device and a plurality of optical subscriber units connected to the intra-station device via an optical fiber line including an optical coupler. And
An optical subscriber unit abnormality detection function for detecting an abnormality of the optical subscriber unit;
Light emission stop command transmission function for transmitting a signal including a light emission stop command for stopping light emission to the optical subscriber apparatus that has detected an abnormality in the optical subscriber apparatus abnormality detection step as downlink communication from the intra-station apparatus to the optical subscriber apparatus. Is executed by the computer of the in-station device. In the abnormal light emission suppression program of the optical subscriber unit according to claim 10,
The optical subscriber unit abnormality detection function detects an idle duration counting function that counts the duration of an idle pattern sent from the optical subscriber unit during idle, and a logical connection established state between the optical subscriber unit When the count output by the logical connection state detection function and the idle duration counting function is longer than a prescribed value determined from the standard of the optical subscriber communication system, and only one logical connection detected by the logical state detection function is established And an optical subscriber unit abnormality determination function for determining that the currently logically connected optical subscriber unit is abnormal, and causing the computer of the intra-station device to execute these functions. Abnormal light emission suppression program for a person's device.

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