JP2008011287A - Alarm notifying method in pon system, subscriber's premise side terminating apparatus, and station side terminal apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten time from detection of the generation of alarm information by a subscriber's premise side terminating apparatus, to notification of the alarm information to a station side terminal apparatus; and to allow the station side terminal apparatus to early start a processing to the alarm information, with respect to the alarm notifying method in PON system, the subscriber's premise side terminating apparatus, and the station side terminal apparatus. <P>SOLUTION: When the generation of alarm information in its own apparatus is detected (1-1); the subscriber's premise side terminating apparatus (ONU) generates an alarm notifying control frame in which the alarm information is stored in the control frame of MPCP protocol, and transmits the alarm notifying control frame to the station side terminal apparatus (OLT) (1-3) at the transmission start timing notified with GATE frame (1-2). The station side terminal apparatus (OLT) receives the control frame from the subscriber's premise side terminating apparatus (ONU), analyzes the control frame, and outputs the alarm information stored in the alarm notifying control frame to the control terminal when judging that the control frame is the alarm notifying control frame. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an alarm notification method in a PON system, a subscriber premises terminal device and a station side terminal device, and in particular, an alarm notification method in a PON (Passive Optical Network) system compliant with the standard of Gigabit Ethernet (registered trademark), The present invention relates to a subscriber-side terminal device and a station-side terminal device.

  Currently, a communication system using an optical fiber is a single star system in which a station side terminal device (OLT: Optical Line Terminal) and a subscriber premises side terminal device (ONU: Optical Network Unit) are connected one-to-one. There is a double star system in which a station-side terminal device (OLT) and a subscriber premises terminal device (ONU) are connected in a 1: n relationship. The PON system according to the present invention is a double star system in which a station-side terminal device (OLT) and a subscriber premises terminal device (ONU) are connected in a 1: n relationship.

  The PON system is an STM-PON, asynchronous transfer mode (ATM :) that communicates between a station-side terminal device (OLT) and a subscriber premises terminal device (ONU) in a synchronous transfer mode (STM) system. Asynchronous Transfer Mode), B-PON, A-PON, and Ethernet (registered trademark) E-PON, GE-PON, which communicate with each other, are roughly classified.

  A schematic configuration of a double star PON system according to the present invention is shown in FIG. In the double-star PON system, one station-side terminal device (OLT) is connected to a plurality of customer premises terminal devices (ONU) # 1 to #N via optical fibers and couplers. The station-side terminal device (OLT) includes an SNI (System Network Interface) as a station-side interface and a PON-IF (PON-Interface) as a subscriber-side interface. On the other hand, the subscriber premises terminal unit (ONU) includes a PON-IF as a station side interface and a UNl (User Network Interface) as a subscriber side interface.

  In a communication system that performs signal transmission / reception in the PON section between a station-side terminal apparatus (OLT) and a subscriber premises terminal apparatus (ONU) # 1 to #N in the Ethernet (registered trademark) system, the station-side terminal apparatus When the subscriber premises terminal units (ONUs) # 1 to #N under the (OLT) send out transmission data frames all at once, the transmission data frames collide at a location where a plurality of optical fibers are aggregated. In order to prevent this, a time division multiple access method is adopted in uplink communication from the subscriber premises terminal unit (ONU) to the station side terminal unit (OLT).

  In order to realize this time division multiple access method in Ethernet (registered trademark) communication, the station-side terminal equipment (OLT) is connected to all the subscriber premises terminal equipment (ONUs) # 1 to # 1 connected under its control. A control frame according to MPCP (Multi Point Control Protocol) which is a closed control protocol in the PON section is always transmitted to and received from N. The control frame includes a GATE frame (Opcode: 00-02) transmitted from the station-side terminal unit (OLT) side and a REPORT frame (Opcode: 00-03) transmitted from the subscriber premises terminal unit (ONU) side. There are.

  The GATE frame is a control frame for notifying the transmission start timing and bandwidth for uplink communication from the station side terminal equipment (OLT) side to the subscriber premises terminal unit (ONU), and the REPORT frame is the subscriber premises frame. This is a control frame for requesting a band required for uplink communication from the side terminal unit (ONU) side to the station side terminal apparatus (OLT). In addition to these control frames, an OAM (Operation Administration and Maintenance) frame for performing alarm notification, monitoring, control, and maintenance is transmitted and received in the PON section.

  FIG. 6A shows the format of the REPORT frame. FIG. 6B shows a conventional sequence from alarm detection to notification. When a subscriber premises terminal unit (ONU) detects an abnormality in its own unit and transmits some alarm information by an OAM frame to notify the station side terminal unit (OLT) (6-1), uplink communication Is a time-division multiple access method, so it receives a GATE frame from the terminal station (OLT) (6-2), and waits for the arrival of the transmission start timing assigned to the own device notified by the GATE frame. Then, a REPORT frame for bandwidth request is transmitted (6-3).

  The subscriber premises terminal unit (ONU) requests a bandwidth required for OAM frame transmission for alarm information notification by this REPORT frame to the station side terminal device (OLT), and the station side terminal device (OLT) In response to this request, the transmission start timing and bandwidth for OAM frame transmission are notified to the subscriber premises terminal unit (ONU) by the GATE frame (6-4).

  Upon receiving the GATE frame, the subscriber premises terminal unit (ONU) transmits an alarm notification OAM frame after waiting for the transmission start timing assigned by the station side terminal unit (OLT) (6-5). For this reason, the subscriber premises terminal unit (ONU) must retain the alarm information until it is possible to transmit the OAM frame even after the occurrence of the alarm information to be notified is detected. Also, at this time, if the link breaks in the OAM layer, an alarm cannot be notified.

  Further, in the uplink communication of GE-PON, a band is dynamically allocated by a station side terminal apparatus (OLT), but an LLID (Logical Link ID) allocated individually for each subscriber premises terminal apparatus (ONU). The more logical paths called, the longer the time required for bandwidth allocation, and the higher the probability that an alarm notification cannot be made from the subscriber premises terminal unit (ONU).

  The following Patent Document 1 describes a method for implementing functions such as initial ONU registration, additional ONU registration, ranging, and dynamic bandwidth allocation in the GE-PON giga system. (A) Periodically after the OLT is initially driven Transmitting a synchronization signal to each of the plurality of ONUs and synchronizing each of the plurality of ONUs with one of the periodically transmitted synchronization signals; and (b) synchronizing with one of the synchronization signals. Together with the ONU knows the transmission start time and transmission time length of the initial registration request frame included in the grant (upward data transmission opportunity allocation) frame, and transmits data with other ONUs at the transmission time of the initial registration request frame. After the random delay to avoid collision, the process of transmitting the initial registration request frame to the OLT; and (c) the initial registration given to the grant frame by the OLT that has received the initial registration request frame. A process of calculating a difference between an expected frame arrival time and an actual frame arrival time expected from the transmission start time of the requested frame and calculating an RTT (Round Trip Time) using a random delay value; and (d) calculating an RTT. After that, the OLT registers an ONU that requests ONU registration in the ONU list, gives a new ONU ID for each of the ONUs, and then requests an ONU registration for a registration response frame including the new ONU ID and RTT. And a process for transmitting to the ONU. The method for implementing the operation of the GE-PON system is described.

Further, in the following Patent Document 2, B-PON (Broadband Passive Optical Network) compatible with DBA (Dynamic Bandwidth Assignment) or ABR (Available Bit Rate) described in “ATM Forum Traffic Management 4.1” A band allocation circuit used for dynamically distributing a band in an apparatus accommodating a connection is described.
JP 2003-244178 A Japanese Patent Laid-Open No. 2003-258883

  The present invention detects the occurrence of alarm information to be notified to the station side terminal apparatus (OLT) in the subscriber premises terminal unit (ONU) and then notifies the station side terminal apparatus (OLT) of the alarm information. The purpose of this is to improve the quality of alarm notification by shortening the time until the station terminal device (OLT) starts processing the alarm information at an early stage.

  The alarm notification method in the PON system according to the present invention is a control protocol between the subscriber-side terminal device and the alarm information when the occurrence of the alarm information in the own device is detected. An alarm notification control frame stored in a control frame transmitted / received by the multipoint control protocol (MPCP) is generated, and the alarm notification control frame is transmitted at a transmission start timing notified by the GATE frame of the multipoint control protocol (MPCP). In the process of transmitting to the station-side terminal device, the station-side terminal device receives a control frame according to the multipoint control protocol (MPCP) from the subscriber premises terminal device, analyzes the control frame, When it is determined that the control frame is the alarm notification control frame, the alarm notification A step of outputting the alarm information stored in the control frame to the control terminal, characterized in that it comprises a.

  In addition, when the subscriber premises terminal device in the PON system of the present invention detects the occurrence of alarm information in its own device, the alarm information is transmitted to the multipoint control which is a control protocol with the station side terminal device. Frame generation means for generating an alarm notification control frame stored in a control frame transmitted / received by a protocol (MPCP), and transmission start timing at which the alarm notification control frame is notified by a GATE frame of the multipoint control protocol (MPCP) And means for transmitting to the station-side terminal device.

  Further, the station-side terminal device in the PON system of the present invention receives a control frame from the subscriber-side terminal device by a multipoint control protocol (MPCP), which is a control protocol with the subscriber-side terminal device, Means for analyzing the control frame, and alarm information stored in the alarm notification control frame when the control frame is determined to be an alarm notification control frame storing alarm information in the subscriber premises terminal device; Means for outputting to a control terminal.

  In addition, after the transmission start timing and the band are notified by the GATE frame in response to the band request by the multipoint control protocol (MPCP) REPORT frame from the subscriber premises terminal apparatus, the subscriber premises terminal is terminated at the transmission start timing and the band. A means for outputting alarm information notified by an OAM frame transmitted from the apparatus to the control terminal is provided.

  The present invention uses a control frame transmitted / received by a multipoint control protocol (MPCP) without using an OAM frame that requires a bandwidth request by a REPORT frame, from a subscriber-side terminal unit (ONU) to a station-side terminal device. Since the alarm information is notified to the (OLT), the alarm information can be quickly notified to the station-side terminal device (OLT) without making a bandwidth request using the REPORT frame.

  By shortening the time from the alarm occurrence detection to the alarm notification in the subscriber premises terminal unit (ONU), the station side terminal unit (OLT) can start processing for the alarm information at an early stage. Notification quality can be improved. Further, by notifying the alarm by using the control frame without using the OAM frame, it is possible to improve the reliability of the alarm notification.

  This is because, in the conventional alarm notification using the OAM frame, the alarm notification cannot be performed because the OAM layer is disconnected. However, if only the control frame layer based on the lower MPCP protocol is established, the alarm according to the present invention is used. This is because the information can be transmitted to the station-side terminal device (OLT).

  Also, the alarm information is maintained until the alarm information can be notified in the subscriber premises terminal unit (ONU) because the time from the alarm occurrence detection to the alarm notification in the subscriber premises terminal unit (ONU) has been shortened. For example, when notifying an alarm such as power-off of a subscriber premises terminal unit (ONU), the capacity of a power storage capacitor or the like for retaining alarm information such as the power-off Can be reduced.

  In the present invention, an alarm notification function is given to a control frame of a multipoint control protocol (MPCP) that is continuously exchanged between a station side terminal device (OLT) and a subscriber premises terminal unit (ONU). . 1A shows a format of a control frame used in the present invention, and FIG. 1B shows a sequence from alarm information generation detection to alarm information notification in a subscriber premises terminal unit (ONU).

  In the present invention, the type of alarm is indicated using the Opcode field present in the control frame of the predetermined multipoint control protocol (MPCP), and the occurrence or recovery of the alarm is indicated using the Flag field. FIG. 1C shows an example of a code indicating the alarm type and alarm occurrence / recovery indicated by the Opcode field and Flag field.

  When the occurrence of alarm information is detected in the subscriber premises terminal unit (ONU) (1-1), an alarm notification control frame in which the alarm information is stored in the control frame is generated, and the GATE frame is transmitted from the station side terminal apparatus. After receiving (1-2), the alarm notification control frame is transmitted to the station-side terminal device at the transmission start timing notified by the GATE frame (1-3). In this way, by providing an alarm notification function to the control frame, alarm information can be instantaneously notified from the subscriber premises terminal unit (ONU) to the station side terminal device (OLT) using the control frame.

  FIG. 2A shows a functional block of the station side terminal device (OLT) in the present invention. In the station side terminal equipment (OLT), the frame received from the PON interface unit 2-10 is divided into a control frame, an OAM frame, and a user data frame by the PON bridge unit 2-11. The data is transferred to the SNI interface unit 2-13 via the unit (PHY) 2-12.

  The control frame is transferred to the MPCP function unit 2-14 by the PON bridge unit 2-11, the control frame is analyzed by the frame analysis unit 2-15, and a bandwidth request message from the subscriber premises terminal unit (ONU) is transmitted. For the REPORT frame included, scheduling of uplink time division multiple access is performed for each logical path (LLID) by a DBA (dynamic bandwidth allocation) scheduler 2-16. Based on the result, the frame generation unit 2-17 generates a GATE frame, and transfers the GATE frame to the PON bridge unit 2-11.

  When the OAM frame is received from the subscriber premises terminal unit (ONU), the PON bridge unit 2-11 determines the OAM frame and transfers it to the OAM function unit 2-18. When the station side terminal device (OLT) receives a control frame with an alarm notification function, the frame analysis unit 2-15 analyzes the control frame, and transmits the control frame with the alarm notification function to the OAM function unit 2- 18 to transfer.

  The OAM function unit 2-18 that has received the control frame with the alarm notification function analyzes the control frame and outputs alarm information of the corresponding subscriber premises terminal unit (ONU) to a control terminal (not shown). With this configuration, the station-side terminal device (OLT) receives the alarm notification frame in which alarm information is stored in the control frame, and processes the alarm notification by the OAM function unit 2-18 as in the conventional case.

  The functional block of the subscriber premises terminal unit (ONU) of the present invention is shown in FIG. In the subscriber premises terminal unit (ONU), the frame received from the PON interface unit 2-20 is divided into a control frame, an OAM frame, and a user frame by the PON bridge unit 2-21. PHY) 2-22 to transfer to the UNI interface unit 2-23.

  The control frame is transferred to the MPCP function unit 2-29 by the PON bridge unit 2-21, the control frame is analyzed by the GATE processing unit 2-24, and the REPORT frame is transferred to the REPORT processing unit 2-25 according to the request contents. To do. The REPORT processing unit 2-25 analyzes the PON bridge unit 2-21 for the requested bandwidth of the data part of the REPORT frame together with the requested content of the REPORT frame, and based on the analysis result, the frame generation unit 2-26 Then, a frame is generated, and a REPORT frame is transmitted to the station side terminal device (OLT) via the PON bridge unit 2-21. The OAM frame is transferred to the OAM processing unit 2-28 by the PON bridge unit 2-21.

  When the subscriber premises terminal unit (ONU) detects the occurrence of alarm information, the alarm information detected by the alarm detection unit 2-27 is transferred to the frame generation unit 2-26 and controlled by the frame generation unit 2-26. A control frame with an alarm notification function in which alarm information is stored in the frame is generated, and the control frame with an alarm notification function is transmitted to the station side terminal at the transmission start timing assigned to the own device via the PON bridge unit 2-21. Transmit to the device (OLT). With this configuration, the subscriber premises terminal unit (ONU) that has detected the occurrence of the alarm can add the alarm information to the control frame and notify the station side terminal unit (OLT).

  Next, a GE in which a subscriber premises terminal unit (ONU) that can transmit a control frame with an alarm notification function and a subscriber premises terminal unit (ONU) that cannot transmit the control frame with an alarm notification function are mixed. -The station side terminal apparatus (OLT) in a PON network is demonstrated.

  As shown in FIG. 5, the PON system is a system that can connect a plurality of customer premises terminal units (ONUs) # 1 to #N under the control of a terminal unit (OLT). Here, when one of the subscriber premises terminal units (ONU) # 1 to #N is not equipped with the alarm notification function by the control frame according to the present invention, the subscriber premises terminal unit (ONU) As in the past, it is necessary to recognize the alarm information by receiving the alarm notification of the subscriber premises terminal unit (ONU) by the OAM frame after the bandwidth allocation request using the REPORT frame.

  In the station side terminal equipment (OLT) in the PON system in the above case, the alarm notification by the conventional OAM frame is received, the PON bridge unit 2-11 transfers the OAM frame to the OAM function unit 2-18, and the OAM function unit 2-18 The function unit 2-18 analyzes in the same manner as other OAM frames, and outputs alarm notification information by the OAM frame to a control terminal or the like.

  With this configuration, the station side terminal device (OLT) is a PON system in which a control frame provided with an alarm notification function according to the present invention and a conventional alarm notification OAM frame are mixedly transmitted. It is possible to recognize an alarm notification by any of the control frame and the OAM frame.

  FIG. 3 shows an embodiment of the present invention. As shown in FIG. 5A, in this embodiment, 32 subscriber terminal units (ONUs) # 1 to # 32 are connected under the control of the terminal station (OLT), and these subscriber homes are connected. The side terminal units (ONU) # 1 to # 32 are a subscriber home side terminal unit (ONU) of a system that gives an alarm notification function to a control frame of the present invention and a subscriber home side of an alarm notification system using a conventional OAM frame. It is assumed that the terminal unit (ONU) is mixed.

  In the embodiment of FIG. 3, it is assumed that the subscriber premises terminal unit (ONU) # 1 adopts a method of adding an alarm notification function to the control frame according to the present invention. Here, assuming that the power supply of the subscriber premises terminal unit (ONU) # 1 is cut off, the subscriber premises terminal unit (ONU) # 1 switches the power supply to the internal power supply simultaneously with the detection of the power supply cut off, and has an alarm notification function. The assigned control frame is generated, and the control frame is transmitted to the station-side terminal device (OLT). FIG. 3B shows a sequence at this time, and FIG. 3C shows a control frame to which power-off information is added.

  In addition, the transmission interval of the GATE frame of the station side terminal apparatus (OLT) of this embodiment is 1 ms, and the delay time (latency) is zero for both the subscriber terminal unit (ONU) and the station side terminal apparatus (OLT). It is assumed that the time required for the subscriber premises terminal unit (ONU) to receive the GATE frame, generate the control frame, and transmit the control frame to the station side terminal unit (OLT) is zero. To do.

  In such a case, as shown in FIG. 3B, a GATE frame is received from the station-side terminal device (OLT) (3-1), and a REPORT frame is transmitted to the GATE frame (3-2). If the occurrence of alarm information is detected (3-3) in the subscriber premises terminal unit (ONU) immediately after, the alarm notification function is added immediately after receiving the next GATE frame (3-4). A control frame is transmitted (3-5). As described above, the time required for the subscriber premises terminal unit (ONU) to notify the alarm after detecting the occurrence of the alarm such as power-off is 1 ms at maximum.

  On the other hand, FIG. 4 shows an alarm notification sequence when the subscriber premises terminal unit (ONU) # 2 of the alarm notification method using the OAM frame detects power failure. Also in this case, it is assumed that both the subscriber premises terminal unit (ONU) and the station side terminal device (OLT) have zero delay time (latency), and the subscriber premises terminal unit (ONU) transmits the OAM frame. It is assumed that the time required for generating the REPORT frame and the time required for transmitting the GATE frame after the station side terminal device (OLT) receives the REPORT frame is zero.

  In the above case, immediately after receiving the GATE frame from the station side terminal apparatus (OLT) (4-1) and transmitting the REPORT frame to the GATE frame (4-2), If the occurrence of alarm information is detected (4-3) in the ONU), the next GATE frame is received (4-4), and then a REPORT frame for OAM frame transmission bandwidth request is transmitted (4- 5) After receiving a GATE frame corresponding to the REPORT frame (4-6), an alarm notification by an OAM frame is transmitted (3-7).

  Accordingly, the time required from the time when the subscriber premises terminal unit (ONU) # 2 detects power-off to the alarm notification by the OAM frame to the station side terminal unit (OLT) is 2 ms at maximum. The alarm notification by the control frame according to the present invention shortens the time from detection of the criminal law information to the alarm notification as compared with the alarm notification by the conventional OAM frame, and thereby the alarm information in the internal circuit of the subscriber premises terminal unit (ONU). Therefore, it is possible to reduce the capacity of a capacitor or the like for power supply for holding and transmitting.

It is a figure which shows an example of the code | cord | chord which shows the format of the control frame used by this invention, the sequence from alarm information generation | occurrence | production detection to alarm information notification by this invention, alarm classification, and generation / recovery of an alarm. It is a figure which shows the functional block of the station side terminal apparatus (OLT) in this invention, and a subscriber home side terminal apparatus (ONU). It is a figure which shows the Example of this invention. It is a figure which shows the alarm notification sequence of the alarm notification system by an OAM frame. It is a figure which shows schematic structure of the PON system of a double star system. It is a figure which shows the format from the format of a REPORT frame and the conventional alarm detection to notification.

Explanation of symbols

2-10 PON interface unit 2-11 PON bridge unit 2-12 SNI physical layer unit (PHY)
2-13 SNI interface section 2-14 MPCP function section 2-15 Frame analysis section 2-16 DBA (dynamic bandwidth allocation) scheduler 2-17 Frame generation section 2-18 OAM function section 2-20 PON interface section 2-21 PON bridge unit 2-22 UNI physical layer unit (PHY)
2-23 UNI Interface Unit 2-24 GATE Processing Unit 2-25 REPORT Processing Unit 2-26 Frame Generation Unit 2-27 Alarm Detection Unit 2-28 OAM Processing Unit 2-29 MPCP Function Unit

Claims (4)

In the alarm notification method of the PON system in which a plurality of subscriber-side terminal devices are connected to one station-side terminal device via optical fibers and couplers,
When the subscriber premises terminal device detects the occurrence of alarm information within itself, the subscriber premises terminal device transmits / receives the alarm information using a multipoint control protocol (MPCP) which is a control protocol with the station side terminal device. The alarm notification control frame stored in the control frame to be generated is generated, and the alarm notification control frame is transmitted to the station side terminal apparatus at the transmission start timing notified by the GATE frame of the multipoint control protocol (MPCP). Process,
The station-side terminal device receives a control frame based on the multipoint control protocol (MPCP) from the subscriber premises terminal device, analyzes the control frame, and the control frame is the alarm notification control frame. A process of outputting the alarm information stored in the alarm notification control frame to the control terminal when determined;
An alarm notification method in a PON system, comprising: In a subscriber premises terminal device of a PON system in which a plurality of subscriber premises terminal devices are connected to one station side terminal device via optical fibers and couplers,
When the subscriber premises terminal device detects the occurrence of alarm information within itself, the subscriber premises terminal device transmits / receives the alarm information using a multipoint control protocol (MPCP) which is a control protocol with the station side terminal device. Frame generating means for generating an alarm notification control frame stored in the control frame to be
Means for transmitting the alarm notification control frame to the station-side terminal device at a transmission start timing notified by a GATE frame of the multipoint control protocol (MPCP);
A subscriber premises terminal device in a PON system. In a station-side terminal device of a PON system in which a plurality of subscriber-side terminal devices are connected to one station-side terminal device via optical fibers and couplers,
The station-side terminal device receives a control frame based on a multipoint control protocol (MPCP), which is a control protocol with the subscriber premises terminal device, from the subscriber premises terminal device, and analyzes the control frame Means to
Means for outputting the alarm information stored in the alarm notification control frame to the control terminal when it is determined that the control frame is an alarm notification control frame storing alarm information in the subscriber premises terminal device;
A station-side terminal device in a PON system, comprising:   After notification of the transmission start timing and bandwidth by the GATE frame in response to the bandwidth request by the REPORT frame of the multipoint control protocol (MPCP) from the subscriber home side termination device, from the subscriber home side termination device at the transmission start timing and bandwidth The station side terminal apparatus in the PON system according to claim 3, further comprising means for outputting alarm information notified by an OAM frame to be transmitted to the control terminal.

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