JP6271368B2 - Slave station, slave station restart method, and communication system - Google Patents

Description

  The present invention relates to a communication terminal technique, and more particularly to a slave station restart technique for restarting a slave station by a remote instruction from the master station in a communication system including a master station and a slave station.

One of communication systems composed of a master station and a plurality of slave stations is a PON (Passive Optical Network) system. This system performs communication using an OLT (Optical Line Terminal) installed in a station as a master station and an ONU (Optical Network Unit) installed in each user's house as a slave station.
FIG. 6 is a configuration example of a conventional PON system. In FIG. 6, the PON system includes m ONUs (slave stations) 50 (m is an integer of 2 or more) connected to the user network 70, and an OLT (master station) 60 connected to the external network 73. The OLT 60 and the m ONUs 50 are composed of an optical splitter 71 and an optical fiber 72 that connect 1: m.

  In the PON system, as shown in FIG. 6, signals transmitted from the respective ONUs 50 are bundled by the optical splitter 72 and reach the OLT 60. Therefore, each ONU 50 communicates with the OLT 60 by the time division multiplexing method so that signals from the respective ONUs 50 do not collide with each other (see, for example, Non-Patent Documents 1-6). In particular, since the PON system is an infrastructure system that constitutes an optical access network, this system is required to suppress maintenance costs and maintenance complexity.

  FIG. 7 is a configuration example of an ONU in a conventional PON system. The conventional ONU 50 includes transceivers 51 and 52 that transmit and receive frames, a processor 53 that performs frame processing such as transfer destination control, output timing control, and frame conversion, and a power switch 54. A frame transmitted from the OLT 60 through the PON section is received by the transceiver 51, processed by the processor 53, and then transmitted from the transceiver 52 to the user network 70. Conversely, a frame transmitted from the user network 70 is received by the transceiver 52 and processed by the processor 53, and then transmitted from the transceiver 51 to the OLT 60 through the PON section. The power switch 54 has a function of turning ON / OFF the power of the ONU 50, and can shut off or restart the power of the ONU 50 by an external input.

  FIG. 8 shows a configuration example of a conventional OLT. The configuration of the OLT 60 is almost the same as that of the ONU 50. The conventional OLT 60 also includes transceivers 61 and 62, a processor 63, and a power switch 64. A frame transmitted from the ONU 50 through the PON section is received by the transceiver 62 and subjected to frame processing by the processor 63, and then transmitted from the transceiver 61 to the external network 73. Conversely, a frame transmitted from the external network 73 is received by the transceiver 61 and processed by the processor 63, and then transmitted from the transceiver 62 to the ONU 50 through the PON section. The power switch 64 has a function of turning on / off the power supply of the OLT 60, and can shut off or restart the power supply of the OLT 60 by an external input.

IEEE Std 802.3avTM -2009: Part3: Carrier Sense Multiple Access with Collision Detection (CSMA / CD) Access Method and Physical Layer Specifications Technology Basic Course [GE-PON Technology], NTT Technical Journal, 2005.8, p72-74 Technology Basic Course [GE-PON Technology], NTT Technical Journal, 2005.9, p91-94 Technology Basic Course [GE-PON Technology], NTT Technology Journal, 2005.10, p67-70 Technology Basic Course [GE-PON Technology], NTT Technology Journal, 2005.11, p59-61 Technology Basic Course [GE-PON Technology], NTT Technology Journal, 2005.12, p51-54

  However, in such a conventional technique, the ONU processor is generally operated by software, and thus may freeze like a personal computer or the like. Freeze here refers to a state in which a watchdog timer or the like that monitors the operation of the processor is being executed, but a frame cannot be transmitted or received normally, that is, the processor can normally execute part of the processing related to communication. Refers to the missing state.

  In such a case, when the processor freezes, the ONU cannot communicate with the OLT, and the ONU cannot be restarted by a remote instruction from the OLT. For this reason, when the user contacts the service provider, the maintenance staff goes to the user's home, and the communication is restored by restarting the ONU by performing an external input to the ONU, such as pressing the reset switch. Will do. Therefore, according to the prior art, there is a problem that maintenance costs increase because a maintenance person needs to go to the user's home.

  The present invention is for solving such problems, and provides a communication terminal technology capable of restarting a slave station by remote instruction from the master station even if the slave station freezes for some reason. It is aimed.

To achieve the above object, a slave station according to the present invention consists of ONU of the PON system connected via a master station and an optical line consisting of OLT of the PON system, the optical line from the master station Is a slave station that inputs a frame received via the processor and processes the frame, monitors the frame input to the processor, and uses the frame as a restart instruction frame to be used in the PON system as a restart instruction frame. A restart instruction detection circuit for outputting a restart signal instructing restart of the slave station when a frame addressed to the own apparatus including an identifier instructing disconnection of communication in a predetermined field is detected. And a power switch for restarting the slave station by controlling power supply in the slave station in response to the restart signal. ing.

  Also, in one configuration example of the slave station according to the present invention, the restart instruction detection circuit extracts, for each identifier, an identifier extractor that extracts a value of each field specified in advance in the frame as an identifier. The identifier is compared with a condition value set in advance for the identifier, and when the identifier and the condition value all match and it is determined that the frame is the restart instruction frame, the restart is performed. And a collator for outputting an activation signal.

  One example of the configuration of the slave station according to the present invention is that the identifier extractor includes four determination field values including Assigned Port, Length / Type, Opcode, and Flags included in the PON system frame. Is extracted as the identifier.

  In addition, one configuration example of the slave station according to the present invention further includes a correction / encryption processing circuit that performs error correction / encryption processing on the frame received from the master station and then inputs the frame to the restart instruction detection circuit. Yes.

Also, the slave station restart method according to the present invention comprises an ONU of the PON system connected via an optical line to a master station consisting of an OLT of the PON system, and received from the master station via the optical line A slave station restart method used in a slave station that inputs and processes a frame to a processor, monitors the frame input to the processor, and uses the frame as a restart instruction frame in the PON system. A step of outputting a restart signal instructing restart of the slave station when a frame addressed to the own device including an identifier instructing disconnection of communication in a predetermined field is detected among the used Register frames ; And a step of restarting the slave station by controlling power supply in the slave station in response to the restart signal. The

The communication system according to the present invention includes a master station made of an OLT of a PON system and a slave station made of an ONU of the PON system, connected via an optical line, between the master station and the slave station. In the communication system for performing data communication by transmitting and receiving a frame, the slave station includes any one of the slave stations described above.

  According to the present invention, even when the ONU processor freezes, the restart instruction detection circuit transmitted from the OLT is detected by the restart instruction detection circuit independent of the processor. A restart signal is output to the power switch. Therefore, even when the processor freezes and the frame from the OLT cannot be processed by the processor, the ONU can be restarted by a remote instruction from the OLT. This eliminates the need for the maintenance staff to go to the user's home and restart the ONU as in the prior art, and as a result, maintenance costs can be greatly reduced.

It is a block diagram which shows the structure of the PON system (communication system) concerning 1st Embodiment. It is a block diagram which shows the structure of ONU (slave station) concerning 1st Embodiment. It is an example of a frame format of a restart instruction frame. It is a structural example of a restart instruction | indication detection circuit. It is a block diagram which shows the structure of ONU concerning 2nd Embodiment. It is a structural example of the conventional PON system. It is a structural example of ONU in the conventional PON system. It is a structural example of the conventional OLT.

Next, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
First, a PON system (communication system) 1 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of a PON system (communication system) according to the first embodiment.

  As shown in FIG. 1, the PON system 1 according to this embodiment includes m ONUs (slave stations) 10 (m is an integer of 2 or more) connected to individual user networks 30, and an external network 33. And an optical splitter 31 and an optical fiber 32 that connect the OLT 20 and the m ONUs 10 at 1: m.

  In this embodiment, a restart instruction for instructing a restart transmitted from the OLT 20 out of the frames input to the processor before the processor that performs frame processing on the frame received from the OLT 20 in the ONU 10. A restart instruction detection circuit for detecting a frame is provided, and the ONU 10 is restarted in response to reception of the restart instruction frame.

[Configuration of ONU (slave station)]
Next, the ONU (slave station) 10 according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating a configuration of an ONU (slave station) according to the first embodiment.
As shown in FIG. 2, the ONU 10 according to the present embodiment includes transceivers 11 and 12, a processor 13, a power switch 14, and a restart instruction detection circuit 15 as main circuit units.

  The transceiver 11 receives a frame transmitted from the OLT 20 through the PON section, inputs the frame to the restart instruction detection circuit 15 before inputting the frame to the processor 13, and the frame processed by the processor 13 in the PON section. And transmitting to the OLT 60.

  The transceiver 12 has a function of receiving a frame transmitted from the user network 30 and inputting the frame to the processor 13, and a function of transmitting a frame processed by the processor 13 to the user network 30.

  The processor 13 includes a CPU and its peripheral circuits. The processor 13 performs frame processing such as transfer destination control and output timing control on the frame input from the transceiver 11 via the restart instruction detection circuit 15, and then performs the transceiver. 12 and a function of performing frame processing on a frame input from the transceiver 12 and then outputting to the transceiver 11.

  The power switch 14 has a function of restarting the ONU 10 by controlling power supply in the ONU 10 in accordance with the restart signal RES output from the external input or the restart instruction detection circuit 15. At this time, power supply to the entire ONU 10 may be temporarily interrupted by the power switch 14, but only power supply to the processor 13 may be temporarily interrupted to reset only the processor 13. In this case, power may be supplied to the restart instruction detection circuit 15 by a system different from the power system of the processor 13. Thus, the stable operation of the restart instruction detection circuit 15 can be maintained without depending on the power supply of the processor 13.

  The restart instruction detection circuit 15 is provided as a circuit unit independent of the processor 13, monitors frames received by the transceiver 11 before being input to the processor 13, and detects a restart instruction frame from these frames. And a function of outputting a restart signal RES instructing restart of the ONU 10 to the power switch 14 when a restart instruction frame is detected from these frames.

  At this time, the restart instruction detection circuit 15 may be provided with a function of inputting the frame to the processor 13 when a frame other than the restart instruction frame is received. If there is no problem even if the restart instruction frame is input to the processor 13, all the frames received by the transceiver 11 may be distributed to the restart instruction detection circuit 15 and the processor 13.

  FIG. 3 is a frame format example of the restart instruction frame. Here, a case will be described in which a frame for instructing disconnection of communication among the Register frames used in a general PON system is used as a restart instruction frame for instructing the ONU 10 to restart from the OLT 20.

  In a general PON system, since a plurality of ONUs are connected to one OLT to perform one-to-many communication, a terminal identifier called LLID (Logical Link ID) is assigned to each ONU. This terminal identifier is described in the field “Assigned Port” in the frame format shown in FIG. Therefore, the condition that the received restart instruction frame is addressed to the self is when the value of the field “Assigned Port” matches the self LLID.

  In this frame format, the condition indicating that the received frame is a Register frame is that the value of the field “Length / Type” is “0x8808” (“0x ...” is “...” in hexadecimal notation). And the value of the field “Opcode” is “0x0005”. Further, the condition indicating that the Register frame instructs to disconnect communication is when the value of the field “Deregister” is “0x02”.

In the present embodiment, the restart instruction detection circuit 15 includes four determination fields including “Assigned Port”, “Length / Type”, “Opcode”, and “Flags” in the frame format of the received frame. The values are extracted as identifiers, and these identifiers are compared with preset condition values “own LLID”, “0x8808”, “0x0005”, and “0x02”,
“Assigned Port = Own LLID”
“Length / Type = 0x8808”
“Opcode = 0x0005”
“Flags = 0x02”
When the condition is satisfied, the restart signal RES is output to the power switch 14.

  FIG. 4 is a configuration example of the restart instruction detection circuit. As shown in FIG. 4, the restart instruction detection circuit 15 according to the present embodiment is provided with an identifier extractor 15A and a collator 15B as main circuit units.

  The identifier extractor 15A extracts four determination field values consisting of “Assigned Port”, “Length / Type”, “Opcode”, and “Flags” from the frame from the OLT 20 received by the transceiver 11 and collates them. It has a function to input to the device 15B.

  The collator 15B includes the determination field values input from the identifier extractor 15A and condition values corresponding to these determination field values set in advance, that is, “own LLID”, “0x8808”, “0x0005”, and It has a function of collating with “0x02” and a function of outputting a restart signal RES to the power switch 14 only when these determination field values and condition values all match.

  Here, a case has been described as an example in which a Deregister type frame is used as a restart instruction frame among the Register frames transmitted from the OLT 20 to the ONU 10, but the present invention is not limited to this. For example, a frame in which a dedicated identifier is prepared for the field “Pad / Reserved” in the frame format of FIG. 3 or a frame in which a dedicated identifier is defined in the “Reserved” value of the field “Flags” is used as the restart instruction frame. Also good.

[Operation of First Embodiment]
Next, the operation of the ONU 10 according to the present embodiment will be described with reference to FIGS.
When the ONU 10 is operating normally, the frame transmitted from the OLT 20 is received by the transceiver 11 through the PON section and input to the restart instruction detection circuit 15.

  If the frame is not a restart instruction frame, the frame is input from the restart instruction detection circuit 15 to the processor 13 and subjected to frame processing, and then transmitted from the transceiver 12 to the user network 30. Conversely, a frame transmitted from the user network 30 is received by the transceiver 12 and processed by the processor 13, and then transmitted from the transceiver 11 to the OLT 20 through the PON section.

  Here, when the processor 13 of the ONU 10 freezes for some reason, the frame input from the restart instruction detection circuit 15 is not normally processed by the processor 13 and is not output to the transceiver 12, for example. In addition, the frame input from the transceiver 12 is not normally processed by the processor 13, and is not output to the transceiver 11, for example. The freeze here refers to a state in which a monitoring process such as a watchdog timer for monitoring the operation of the processor 13 is being executed, but a frame cannot be normally transmitted / received, that is, the processor 13 normally performs a part of processing related to communication. This refers to the state where execution is disabled.

For this reason, a malfunction occurs in the communication service provided by the PON system 1 at the user terminal connected to the user network 30 under the ONU 10.
In response to this, when the user informs the service provider of the malfunction of the communication service, a restart instruction frame that can be detected by the restart instruction detection circuit 15 is transmitted from the OLT 20 to the frozen ONU 10 by the service provider. It will be.

As a result, the restart instruction frame transmitted from the OLT 20 is received by the transceiver 11 of the ONU 10 through the PON section and input to the restart instruction detection circuit 15.
The identifier extractor 15A of the restart instruction detection circuit 15 is used for four determinations including “Assigned Port”, “Length / Type”, “Opcode”, and “Flags” from the restart instruction frame input from the transceiver 11. The field value is extracted and input to the collator 15B.

In response to this, the collator 15B receives the determination field values input from the identifier extractor 15A and the condition values corresponding to these determination field values set in advance, that is, “own LLID”, “0x8808”, Collate with “0x0005” and “0x02”.
Here, if the frame input from the transceiver 11 is a restart instruction frame, and the field values for determination and the condition values all match, the collator 15B outputs a restart signal RES to the power switch 14.

In response to the restart signal RES output from the restart instruction detection circuit 15, the power switch 14 temporarily turns off the ONU 10 and turns it on again. As a result, the ONU 10 is restarted, the freeze of the processor 13 is reset, and normal frame processing is started.
Therefore, even when the processor 13 that performs frame processing in the ONU 10 freezes, the restart instruction detection circuit 15 can receive the restart instruction frame from the OLT 20 and instruct the power switch 14 to restart. The ONU 10 can be restarted by a remote instruction from the OLT 20.

[Effect of the first embodiment]
As described above, in this embodiment, in the ONU (slave station) 10, the restart instruction detection circuit 15 monitors the frame input to the processor 13, and the restart instruction frame is detected from these frames. In this case, a restart signal RES for instructing restart of the ONU 10 is output, and the power switch 14 controls the power supply in the ONU 10 in accordance with the restart signal RES, so that the ONU 10 is restarted. It is designed to start up.

  Thereby, even when the processor 13 of the ONU 10 is frozen, the restart instruction detection circuit 15 transmitted from the OLT 20 is detected by the restart instruction detection circuit 15 independent of the processor 13. A restart signal RES is output to the power switch 14. Therefore, even when the processor 13 freezes and the frame from the OLT 20 cannot be processed by the processor 13, the ONU 10 can be restarted by a remote instruction from the OLT 20. This eliminates the need for the maintenance staff to go to the user's home and restart the ONU as in the prior art, and as a result, maintenance costs can be greatly reduced.

In this embodiment, an example in which the restart instruction detection circuit 15 is configured only by hardware has been described. However, the present invention is not limited to such a configuration, and the configuration independent from the processor 13 that processes a frame. If it is. For example, the restart instruction detection circuit 15 may be configured by a processor physically different from the processor 13 that processes a frame.
In the present embodiment, the configuration example in which all the frame processing is processed by software on the processor 13 has been described. However, the present invention is not limited to such a configuration, and is partially hardware. Needless to say, it may be configured to be processed.

  In the present embodiment, a PON system Register (type: Deregister) frame is used as an example of a frame for the restart instruction detection circuit 15 to detect the restart, but the restart instruction frame is included in this frame. It is not limited. For example, it is needless to say that an extended MAC control frame used in a general PON system, an extended OAM frame, or a dedicated frame may be defined.

  In the present embodiment, the PON system has been described as an example of a communication system composed of a master station and a slave station, but the present invention is not limited to the PON system. For example, a system in which a management server in a data center is a master station and each data server is a slave station. In a local area LAN system, each switch or user terminal is a slave station and a server that manages the LAN system is a master station. It may be a system.

[Second Embodiment]
Next, an ONU (slave station) 10 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram illustrating a configuration of an ONU according to the second embodiment.
In the first embodiment, the configuration in which the processor 13 executes all frame processing and the restart instruction detection circuit 15 is provided in the preceding stage has been described as an example. In the present embodiment, a configuration example in which part of the frame processing is performed in the previous stage of the restart instruction detection circuit 15 will be described.

Common communication devices are equipped with an error correction function that corrects errors that occur during signal transmission and an encryption function that prevents others from reading the communication contents during transmission. ing.
Therefore, in the first embodiment, when an error is included in the received signal or when encryption is applied, the restart instruction detection circuit 15 accurately determines the restart instruction frame from the OLT 20. It may become impossible to detect.

  In the present embodiment, in consideration of the case where the error correction function and the encryption function are installed in the ONU 10 which is such a slave station, as shown in FIG. An error correction / encryption processing circuit 16 for performing encryption processing is provided.

  That is, in this embodiment, the correction / encryption processing circuit 16 performs error correction / encryption processing on the frame input from the transceiver 11 and then inputs the frame to the restart instruction detection circuit 15 and the processor 13 performs frame processing. And a function of outputting the data to the transceiver 11 after error correction / encryption processing of the received frame.

  The correction / encryption processing circuit 17 performs an error correction / encryption process on the frame input from the transceiver 12 and then inputs it to the processor 13 and an error correction / encryption process on the frame processed by the processor 13. And a function of outputting to the transceiver 12. The error correction / encryption processing circuit 17 is not an indispensable configuration for applying this embodiment, but in general, when the ONU 10 is equipped with an error correction function or encryption function, not only the OLT 20 side but also the user For the frame transmitted / received to / from the network 30 side, the correction / encryption processing circuit 17 is provided to perform error correction processing and encryption processing.

[Operation of Second Embodiment]
Next, the operation of the ONU 10 according to the present embodiment will be described with reference to FIG. 2 and FIG.
When the ONU 10 is operating normally, the frame transmitted from the OLT 20 is received by the transceiver 11 through the PON section, subjected to error correction / encryption processing by the correction / encryption processing circuit 16, and then input to the restart instruction detection circuit 15. Is done.

  Here, when the processor 13 of the ONU 10 freezes for some reason, when the user informs the service provider of the malfunction of the communication service, the restart instruction frame that can be detected by the restart instruction detection circuit 15 is frozen by the service provider. Is transmitted from the OLT 20 to the ONU 10 that has performed.

Thus, the restart instruction frame transmitted from the OLT 20 is received by the transceiver 11 of the ONU 10 through the PON section, subjected to error correction / encryption processing by the correction / encryption processing circuit 16, and then input to the restart instruction detection circuit 15. The
At this time, even if the restart instruction frame includes an error or the restart instruction frame is encrypted, the restart instruction frame that has been subjected to error correction / encryption processing by the correction / encryption processing circuit 16 is restarted. This is input to the activation instruction detection circuit 15.

  Therefore, the restart instruction detection circuit 15 detects a restart instruction frame from the frames input to the processor 13, outputs a restart signal RES instructing restart of the ONU 10, and the power switch 14 The ONU 10 is restarted by controlling the power supply in the ONU 10 according to the restart signal RES.

[Effect of the second embodiment]
As described above, in this embodiment, in the ONU (slave station) 10, the restart instruction detection circuit 15 performs error correction / encryption processing on the frame received from the OLT 20 and then inputs the frame to the restart instruction detection circuit 15. It is a thing.
As a result, if an error occurs in the restart instruction frame or if it is encrypted, the received frame is input to the restart instruction detection circuit 15 after error correction / encryption processing. It becomes possible to restart correctly.

[Extended embodiment]
The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. In addition, each embodiment can be implemented in any combination within a consistent range.

  DESCRIPTION OF SYMBOLS 1 ... PON system (communication system), 10 ... ONU (slave station), 11, 12 ... Transceiver, 13 ... Processor, 14 ... Power switch, 15 ... Restart instruction detection circuit, 15A ... Identifier extractor, 15B ... Collator 16, 17 ... error correction / encryption processing circuit, 20 ... OLT (master station), 30 ... user network, 31 ... optical splitter, 32 ... optical fiber, 33 ... external network.

Claims (6)

This is a slave station that consists of an ONU of the PON system connected via an optical line to a master station consisting of an OLT of the PON system, and that inputs a frame received from the master station via the optical line to the processor for processing. And
The own device that monitors the frame input to the processor and includes an identifier instructing disconnection of communication in a predetermined field of a Register frame used in the PON system as a restart instruction frame from among these frames When a destination frame is detected, a restart instruction detection circuit that outputs a restart signal instructing restart of the slave station,
A slave station comprising: a power switch that restarts the slave station by controlling power supply in the slave station according to the restart signal. In the slave station according to claim 1,
The restart instruction detection circuit includes:
An identifier extractor for extracting the value of each field specified in advance in the frame as an identifier;
When the identifier and the condition value set in advance for the identifier are checked for each identifier, and the identifier and the condition value all match and it is determined that the frame is the restart instruction frame And a collator for outputting the restart signal. In the slave station according to claim 2 ,
The identifier extractor extracts four determination field values including Assigned Port, Length / Type, Opcode, and Flags included in a frame of the PON system as the identifier. In the slave station according to any one of claims 1 to 3 ,
A slave station further comprising a correction / encryption processing circuit that performs error correction / encryption processing on the frame received from the master station and then inputs the frame to the restart instruction detection circuit. Used by a slave station that consists of an ONU of the PON system connected via an optical line with a master station consisting of an OLT of the PON system, and that inputs a frame received from the master station via the optical line to the processor for processing. A slave station restart method,
The own device that monitors the frame input to the processor and includes an identifier instructing disconnection of communication in a predetermined field of a Register frame used in the PON system as a restart instruction frame from among these frames When a destination frame is detected, outputting a restart signal instructing restart of the slave station; and
And restarting the slave station by controlling power supply in the slave station in response to the restart signal. It is provided with a master station made up of an OLT of a PON system and a slave station made up of an ONU of the PON system connected via an optical line, and data communication is performed by transmitting and receiving frames between the master station and the slave station It is a communication system to perform, Comprising: The said sub_station | mobile_unit consists of a sub_station | mobile_unit as described in any one of Claims 1-4 .

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