JP6418958B2 - Slave station device, communication system, and failure identification method - Google Patents

Description

  The present invention relates to a slave station device, a communication system, and a failure identification method.

  As a digital signal transmission method for transmitting data using a communication cable, for example, there is an Ethernet (registered trademark) technique defined in IEEE (The Institute of Electrical and Electronics Engineers) -802.3. Further, as a digital signal transmission method using a data transmission medium as an optical fiber, there is GE-PON (Gigabit Ethernet (registered trademark) -Passive Optical Network) defined in IEEE-802.3-2008 (non-patent). Reference 1).

  As failure modes in GE-PON, there are communication device failures, transmission medium failures, network failures, and the like. For example, when there is a failure in the transmission medium, the failure is specified by transmitting data for failure analysis between communication nodes including the transmission medium.

  As an example of the failure identification method, a first device as a communication device and a second device as another communication device are connected by a transmission medium, and one of these devices is used for failure analysis from the other device. There is a method of specifying a failure site by transmitting return test data. When the second device performs the failure analysis, the second device transmits the return test data for failure analysis to the first device as the opposite communication device. When there is a failure in the transmission medium, the transmitted return test data does not arrive at the opposite communication device. For this reason, if the second device that transmitted the return test data does not receive the returned return test data within the designated waiting time, the transmission medium has a failure or the opposite communication device has a failure. to decide. In addition, when an optical pulse tester is used as a communication device that transmits return test data for failure analysis, a technique called an OTDR (Optical Time Domain Reflectometer) method is used to cause a loss due to a transmission medium failure and a failure point in the transmission medium. And the failure degree indicating the degree of the transmission medium failure can be determined.

  As another example of the failure identification method, a case where the second device performs failure analysis and the first device has a failure will be described. In this case, the second device transmits the return test data for failure analysis to the first device as the opposite communication device. The loopback test data includes information indicating the loopback point of the first device (loopback point information). The first device cannot return the return test data when there is a failure in front of the return point (that is, the side closer to the second device). For this reason, when the second apparatus does not receive the returned loop test data within the waiting time, the transmission medium has a failure or is ahead of the loop point of the first apparatus (that is, the side closer to the second apparatus). It is determined that there is a faulty part. On the other hand, when the second device receives the returned loop test data within the waiting time, there is a failure site behind the loopback point of the first device (that is, the side away from the second device). Judge.

  In these failure identification methods, one of the first device and the second device transmits the failure analysis loopback test data and monitors whether or not the loopback test data returned from the other device is received. Thus, the failure part is specified (for example, refer to Patent Documents 1 and 2).

  Japanese Patent Application Laid-Open No. 2004-228688 discloses a technique that enables a plurality of return points for a return test to be set in an ONU (Optical Network Unit) serving as a communication device when specifying a failure site.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique that makes it possible to determine a failure in a logical layer by including a logical layer in a return point for a return test, which is used when a failure site is specified.

  Further, Patent Documents 3 and 4 show that when the subscriber's home side communication device (ONU) is a GBIC (Gigabit Interface Converter) module or an SFP (Small Form Factor Pluggable) module, The technology to return is disclosed.

JP 2007-142529 A JP 2008-109654 A Japanese Patent No. 4044127 JP 2009-111507 A

IEEE Std 802.3 (TM) -2008, "IEEE Standard for Information technology-Telecommunication and information exchange between systems- Local and metropolitan area networks- Specific requirements Part3: Carrier sense multiple access with Collision Detection (CSMA / CD) Access Method and Physical Layer Specification ", LAN / MAN Standards Committee of the IEEE Computer Society (issued December 26, 2008)

  According to the above prior art, it is possible to detect the presence of two communication devices connected via a transmission medium and a failure between them. However, in the above prior art, for example, when a communication terminal is connected to a slave station device as one communication device, the master station device as the other communication device fails when there is no failure in the transmission medium. There is a problem that it cannot be determined whether the part is in the slave station device or the communication terminal. For this reason, when multiple communication terminals are connected to the slave station device, it is possible to detect the presence of a failure, but it is not possible to determine which communication terminal has the failure part. It was necessary to replace all of the plurality of communication terminals suspected of malfunctioning.

  Therefore, the present invention has been made in view of the above-described problems of the prior art, and in addition to the failure part of the slave station device, the slave part that can also specify the failure part of the communication terminal connected to the slave station device. An object is to provide a station apparatus, a communication system, and a failure identification method.

  A slave station device according to the present invention is a slave station device that communicates with a master station device via a transmission medium and communicates with a communication terminal, and communicates with the communication terminal. An interface switching unit that performs interface switching for setting one of the plurality of interfaces to be used, and the loopback test data transmitted from the master station device is looped back. A return point control unit for setting a return point, and when the slave station device receives the return test start notification data for notifying the start of the return test from the master station device, the return point control unit, A return point is set, and the interface switching unit sets the set return point in the communication terminal. If set, the interface is switched according to the set turn-back point, and then a preparation response is sent to the master station device to notify that the preparation for the turn-back test is completed, and the slave station device When the set loopback point is set in the communication terminal, when the loopback test data is received, the data signal interface that is the interface set by the interface switching is used. The received loopback test data is transmitted to the loopback point.

  A communication system according to the present invention is a communication system including a slave station device that communicates with a master station device via a transmission medium, and a communication terminal that communicates with the slave station device. The slave station device has a plurality of interfaces for communication with the communication terminal, and performs interface switching for setting an interface to be used to one of the plurality of interfaces. And a loopback point control unit for setting a loopback point at which loopback test data transmitted from the master station device is looped back, and the slave station device notifies the loopback test start notification from the master station device. When data is received, the wrapping point control unit sets the wrapping point and switches the interface. When the set turn-back point is set in the communication terminal, the interface is switched according to the set turn-back point, and then the preparation for notifying that the preparation for the turn-back test is completed. A response is transmitted to the master station device, and the slave station device is set by switching the interface when the return test data is received when the set return point is set in the communication terminal. The received loopback test data is transmitted to the loopback point using a data signal interface that is the interface that has been received.

  A failure identification method according to the present invention is a communication system including a slave station device that communicates with a master station device via a transmission medium and a communication terminal that communicates with the slave station device. , The slave station apparatus performs interface switching for setting one of a plurality of interfaces for communication with the communication terminal to be used, and a loopback test transmitted from the master station apparatus A failure identification method in the communication system for setting a loopback point at which data is looped back when the slave station apparatus receives loopback test start notification data for notifying the start of a loopback test from the master station apparatus. A step of setting a return point; and when the set return point is set in the communication terminal, the set return point The interface is switched in response to an event, and then a preparation response for notifying that the preparation for the return test is completed is transmitted to the master station device, and the set return point is set in the communication terminal. If the loop test data is received, a step of transmitting the received loop test data to the loop point using the data signal interface that is the interface set by the interface switching. It is characterized by having.

  According to the present invention, since the return point of the return test data for failure analysis can be arbitrarily set in the communication terminal connected to the slave station device, the failure part of the communication terminal can be specified. Since the failure part of the communication terminal can be identified in this way, even if a plurality of communication terminals are connected to the slave station device, replacement of all communication terminals is not required, and therefore It is possible to improve the efficiency of the recovery work at the time of occurrence. Further, since the failure part of the communication terminal can be specified, it is not necessary to collect the slave station device when the communication terminal fails.

It is a sequence diagram which shows the failure specific method of a comparative example. It is a figure which shows the failure identification method and turnaround point of a comparative example. It is a block diagram which shows roughly the structural example of the communication system of Embodiment 1 of this invention. 3 is a block diagram illustrating a configuration example of an ONU serving as a slave station device according to the first embodiment. FIG. 3 is a block diagram illustrating a configuration example of an OLT as a master station device according to the first embodiment. FIG. 3 is a block diagram illustrating a configuration example of a communication terminal connected to an ONU according to Embodiment 1. FIG. 3 is a block diagram illustrating a configuration example of a communication terminal connected to the OLT according to Embodiment 1. FIG. FIG. 3 is a sequence diagram illustrating an example of a failure identification method according to the first embodiment. 4 is a flowchart illustrating a turn-back point setting process and an interface switching process in the ONU according to the first embodiment. (A) And (b) is a figure which shows the structural example of the interface switching part in ONU of Embodiment 1. FIG. It is a sequence diagram which shows an example of the failure identification method of Embodiment 2 of this invention. It is a sequence diagram which shows an example of the failure identification method of Embodiment 3 of this invention. It is a hardware block diagram which shows the structure of ONU of Embodiment 1-3 of this invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, first, a comparative example (example in which a failure part of a communication terminal connected to a slave station device cannot be specified) will be described based on FIG. 1 and FIG. 1 to 3 (an example in which a failure part of a communication terminal connected to a slave station device can be specified) will be described in detail with reference to FIGS. The present invention is not limited to the first to third embodiments described below.

《Comparative example》
FIG. 1 is a sequence diagram illustrating a failure identification method of a comparative example. In the comparative example of FIG. 1, the second device 120 as a master station device (communication device) provides data (for example, return test start notification data and return test data) to the first device 110 as a slave station device (communication device). Etc.) and the failure part of the first device 110 is specified. In this failure identification method, first, the second device 120 determines whether there is a failure or failure such as a communication device failure, a transmission medium failure, and a network failure (step S101). For example, this determination is performed based on failure or failure detection information (step S101a) transmitted from the communication terminal 140 connected to the second device 120, a communication log in the second communication device 120, or the like. Or the like. After this determination, the second device 120 transmits return test start notification data to the first device 110 (step S102). The first device 110 that has received the loopback test start notification data extracts information indicating the loopback point from the received loopback test start notification data when necessary (step S103), and loops back based on the extracted information. Points are set (step S104). The first device 110 that has received the loopback test start notification data does not need the loopback point to be extracted (for example, when information indicating a predetermined loopback point is stored or another method is used to store the loopback point). When the information shown is acquired), the return point is set based on the information stored or obtained by another method without extracting the return point (step S104a).

  The first device 110 that has set the return point transmits a preparation response (that is, a preparation completion response signal) notifying that the preparation for the return test has been completed to the second device 120 (step S105). The second device 120 that has received the preparation response transmits the return test data to the first device 110 (step S106). The second apparatus 120 that has transmitted the loopback test data waits for reception of the loopback test data returned during a predetermined waiting time that is a reception waiting period of the loopback test data returned from the loopback point of the first apparatus 110. Transition to the state. On the other hand, when the first apparatus 110 receives the return test data after transmitting the preparation response (step S105), the first apparatus 110 returns the return test data returned at the set return point (step S107). When the second apparatus 120 receives the returned loop test data, the second apparatus 120 determines that there is no failure or failure ahead of the loop point of the first apparatus 110 (that is, the side closer to the second apparatus 120) (step S108). ). Further, when the second device 120 does not receive the returned loop test data, the second device 120 determines that there is a failure or failure ahead of the loop point of the first device 110 (that is, the side closer to the second device 120). .

  FIG. 2 is a diagram illustrating a failure identification method of the comparative example and a turn-back point in the first device 110. FIG. 2 shows an operation example when the communication terminal 130 is connected to the first device 110 of FIG. 1 via the transmission medium 2. The basic operation in the fault identification method shown in FIG. 2 is the same as the operation shown in FIG. In the comparative example of FIG. 2, the second device 120 determines whether there is a failure such as a communication device failure, a transmission medium failure, a network failure, or the like before starting the identification of the failure part (step S201). ). For example, the second device 120 determines whether there is a failure or failure based on detection information (step S201a) transmitted from the communication terminal 140 connected to the second device 120, and based on a communication log or the like. The second device 120 alone determines whether there is a failure or failure. After this determination, the second device 120 transmits return test start notification data to the first device 110 (step S202). The first apparatus 110 that has received the loopback test start notification data extracts information indicating the loopback point from the received loopback test start notification data when necessary (step S203), and the loopback point based on the extracted information. Is set (step S204). If extraction of the folding point is not necessary, the first device 110 sets a predetermined folding point or a folding point acquired by another method (step S204a). FIG. 2 shows a case where the turn-back point is set to one processing block (a rectangular processing block indicated by a broken line) among a plurality of processing blocks in the first device 110.

  The first device 110 that has set the return point transmits a preparation response notifying that the preparation for the return test is completed to the second device 120 (step S205). The second device 120 that has received the preparation response transmits return test data (step S206). After transmitting the loopback test data (step S206), the second device 120 shifts to a loopback test data reception standby state for a predetermined standby time. On the other hand, if the first device 110 receives the return test data after transmitting the preparation response (step S205), the first device 110 returns the return test data at the set return point (step S207). In the example of FIG. 2, the return test data passes through the processing blocks 1, 2, and 3 in the first device 110 in the downstream direction (the direction from the second device 120 toward the communication terminal 130), and is set as a return point. In this processing block, the transmission direction is switched from the downlink direction to the uplink direction and returned. In this case, the second device 120 has a failure or failure in front of the turn-back point in the first device 110 (ie, the side closer to the second device 120) (for example, a failure in the processing blocks 1, 2, and 3) It is determined that a failure in the transmission medium between the first device 110 and the second device 120 has not occurred (step S208).

  In the failure identification method of the comparative example described with reference to FIGS. 1 and 2, when the second device 120 receives the returned return test data during the standby time, the second device 120 is forward of the return point (that is, the second It is determined that there is no failure or failure on the side close to the device 120, that is, there is a failure or failure behind the turn-back point (that is, the side away from the second device 120). However, in the failure identification method of the comparative example, when any of the processing block #, the transmission medium 2 and the communication terminal 130 shown in FIG. On the other hand, according to the slave station apparatus, the communication system, and the failure identification method of the first to third embodiments described below, not only the failure part of the slave station apparatus but also the communication connected to the slave station apparatus The failure part of the terminal can also be specified.

Embodiment 1
FIG. 3 is a block diagram schematically showing a configuration example of the communication system according to the first embodiment of the present invention. As shown in FIG. 3, the communication system according to the first embodiment includes an ONU (Optical Network Unit) 10 as a slave station device and an OLT (master network device) connected to the ONU 10 via the transmission medium 1 so as to be communicable. Optical Line Terminal) 20, a communication terminal 30 that is communicably connected to the ONU 10 via the transmission medium 2, and a communication terminal 40 that is communicably connected to the OLT 20 via the transmission medium 3. However, the communication system of the first embodiment may be a system that does not include the communication terminal 40. 3 shows one communication terminal 30 as a communication terminal connected to the ONU 10, but the communication system may be a system including a plurality of communication terminals 30 connected to the ONU 10. Good. Further, although one ONU 10 is shown in FIG. 3, the communication system may be a system including a plurality of ONUs 10 connected to the OLT 20. 3 shows one communication terminal 30, the communication system may be a system including a plurality of communication terminals 30 connected to the ONU 10.

  The ONU 10 and the OLT 20 can transmit and receive information to and from each other via the transmission medium 1. The transmission medium 1 includes, for example, an optical fiber cable and an optical coupler.

  The communication terminal 30 is, for example, an HGW (Home Gateway) device, a VoIP (Voice over Internet Protocol) device, a PC (Personal Computer), or the like. The communication terminal 30 and the ONU 10 can transmit / receive information to / from each other via the transmission medium 2. The transmission medium 2 is not particularly limited as long as it is an information transmission medium. The transmission medium 2 is, for example, a LAN (Local Area Network) cable. When the ONU 10 is an MSA (Multi-Source Agreement) interface module such as a GBIC module and an SFP module, the communication terminal 30 is connected to the ONU 10 and these are integrated into the transmission medium 2. Can be omitted.

  In the first embodiment and each embodiment described later, a case where the communication system to which the present invention is applied is a GE-PON system will be described. However, the communication system to which the present invention can be applied is not limited to the GE-PON system, and the present invention can be applied to other communication systems other than the GE-PON system.

  Further, in this application, the information flow direction (signal transmission direction) from the OLT 20 to the communication terminal 30 via the ONU 10 is referred to as “downward direction”, and the information flow direction in the reverse direction (signal transmission direction). ) Is called “upward”. Further, data transmitted in the uplink direction is referred to as “uplink data”, data transmitted in the downlink direction is referred to as “downlink data”, and both uplink data and downlink data are collectively referred to as “upper and lower data”.

  Further, in the present application, “return test start notification data” transmitted from the OLT 20, “return test data” transmitted from the OLT 20, “returned return test data” transmitted from the ONU 10, etc. Also called “data”.

  In the present application, the return test start notification data transmitted from the OLT 20 to the ONU 10 at the start of the return test includes information indicating the return point of the return test data. However, if the loopback point is known due to the configuration of the communication system, or if the OLT 20 can notify the loopback point by another method (data other than the loopback test start notification data), the loopback test start notification data Does not have to include information indicating the turning point. When the loopback test data arrives at the loopback point as downlink data, the loopback test data transmission direction is switched from the downlink direction to the uplink direction at the loopback point. When the loopback test data arrives at the loopback point as uplink data, the transmission direction of the loopback test data is switched from the uplink direction to the downlink direction at the loopback point.

  Next, each structure of the communication system of Embodiment 1 is demonstrated in detail. As shown in FIG. 3, the ONU 10 is a communication device that communicates with the OLT 20 via the transmission medium 1 and also communicates with the communication terminal 30. The ONU 10 includes a plurality of interfaces for communication with the communication terminal 30 and includes an interface switching unit 14 that performs interface switching for setting one of the plurality of interfaces to be used. Further, the ONU 10 includes a loopback point control unit 12 that sets a loopback point at which the transmitted loopback test data is looped back in the ONU 10 or the communication terminal 30. Further, the ONU 10 includes an upper communication processing unit 11 that communicates with the upper OLT 20 and a lower communication processing unit 13 that communicates with the lower communication terminal 30. The ONU 10 includes a control unit and an information storage unit (memory) that control various operations of the entire ONU 10 including the upper communication processing unit 11, the return point control unit 12, the lower communication processing unit 13, and the interface switching unit 14. ). When the ONU 10 receives the return test start notification data transmitted from the OLT 20, the return point control unit 12 sets the return point in the ONU 10 or the communication terminal 30, and the interface switching unit 14 sets the set return point. The interface is switched so that the interface corresponding to the is set. Thereafter, when the ONU 10 receives the loopback test data transmitted from the OLT 20, the ONU 10 transmits the received loopback test data in the downstream direction toward the loopback point using the interface set by the interface switching. The loopback test data that arrives at the loopback point is returned to the OLT 20 by switching the transmission direction from the downlink direction to the uplink direction at the loopback point.

  As shown in FIG. 3, the OLT 20 has a lower communication processing unit 22 that communicates with the lower ONU 10 and a failure determination that determines whether there is a failure such as a communication device failure, a transmission medium failure, a network failure, or the like. Part 21. In addition, the OLT 20 may include a control unit that controls various operations of the OLT 20 including the lower communication processing unit 22 and the failure determination unit 21 and an information storage unit (memory).

  As illustrated in FIG. 3, the communication terminal 30 includes a host communication processing unit 31 that communicates with the ONU 10 that is a host device of the communication terminal 30, and a loopback point that sets a loopback point based on the processing content of the host communication processing unit 31. The control part 32 and the low-order communication process part 33 which communicates with the low-order apparatus of the communication terminal 30 are provided. The lower communication processing unit 33 communicates with one or a plurality of lower devices such as an HGW device, a VoIP device, and a PC, for example. In addition, the communication terminal 30 includes a control unit that controls various operations of the communication terminal 30 including an upper communication processing unit 31, a turn-back point control unit 32, and a lower communication processing unit 33, and an information storage unit (memory). May be provided.

  As illustrated in FIG. 3, the communication terminal 40 includes a failure notification unit 41 that notifies the OLT 20 of a failure such as a failure of a communication device, a transmission medium failure, and a network failure. The communication terminal 40 is installed, for example, in a carrier station (parent station) building that operates the system, and constantly monitors abnormalities in the system. The method in which the communication terminal 40 is notified of the presence of a failure or failure and the method for notifying the OLT 20 of the presence of a failure or failure are known methods and are not particularly limited. The communication terminal 40 is a management device that manages a communication device such as the OLT 20, the ONU 10, and the communication terminal 30 or a communication network including them.

  Next, the failure identification method in the communication system of Embodiment 1 is demonstrated. In the communication system according to the first embodiment, when the communication terminal 40 learns of a failure or failure in the communication system or when the OLT 20 determines that there is a failure in the communication system, the OLT 20 notifies the loopback test start. Data is transmitted as downlink data. Specifically, the OLT 20 notified from the communication terminal 40 that there is a failure or failure transmits the return test start notification data to the ONU 10. When the ONU 10 receives the loopback test start notification data transmitted by the OLT 20, the ONU 10 extracts information indicating the loopback point from the loopback test start notification data, and sets a point based on the extracted information as the loopback point.

  When the designated return point is the communication terminal 30 connected to the ONU 10 (a processing block in the communication terminal 30), the ONU 10 determines that the interface used for communication with the communication terminal 30 is the interface switching unit 14. Check which of the multiple interfaces in. At this time, when the ONU 10 uses only the specified data signal interface for communication with the communication terminal 30, or when the ONU 10 is an MSA interface module such as a GBIC module or an SFP module. The interface switching unit 14 of the ONU 10 performs interface switching for setting the interface to be used as an interface corresponding to the turn-back point (described as step S5 in FIG. 8 described later). However, when the specified data signal interface includes an interface necessary for setting the turn-back point, this interface switching need not be performed.

  The ONU 10 instructs the communication terminal 30 to set the return point after switching the interface for setting the return point or when the interface change is unnecessary. An instruction method by the ONU 10 at this time is a method in which the return point control unit 12 of the ONU 10 sets a return point of the communication terminal 30 (direct control), or the ONU 10 transmits the instruction content to the communication terminal 30, and the communication terminal 30. Any of the methods (indirect control) in which the folding point control unit 32 sets the folding point may be used. When the interface switching unit 14 performs interface switching, when the ONU 10 directly gives a setting instruction to the upper communication processing unit 31 or the lower communication processing unit 33 of the communication terminal 30, this corresponds to direct control. On the other hand, when the setting instruction of the ONU 10 relays the return point control unit 32 of the communication terminal 30, it corresponds to indirect control. However, in the first embodiment, a case will be described in which the ONU 10 recognizes in advance whether to perform direct control or indirect control at the time of interface switching. That is, the ONU 10 possesses in advance information regarding the interface of the communication terminal 30 after the interface switching.

  When the return point is set in the communication terminal 30, the communication terminal 30 notifies the ONU 10 of the completion of the return point setting. When the interface switching unit 14 of the ONU 10 receives the notification of the setting completion, the interface switching unit 14 sets the interface used for communication with the communication terminal 30 in order to transmit the loopback test data to the communication terminal 30. In FIG. 8 described later, this is described as step S6). After the interface is switched or when the data signal interface is already usable, the ONU 10 transmits a preparation response (preparation completion response signal) for notifying the OLT 20 that the preparation for the loopback test is completed. After receiving the preparation response, the OLT 20 transmits the return test data to the ONU 10. The ONU 10 transfers the loopback test data as it is to the communication terminal 30, and the communication terminal 30 switches the transmission direction of the loopback test data from the downlink direction to the uplink direction at the set loopback point. The loopback test data returned from the communication terminal 30 is transmitted to the OLT 20 via the ONU 10.

  FIG. 4 is a block diagram illustrating a configuration example of the ONU 10 according to the first embodiment. FIG. 4 shows the configuration of the ONU 10 shown in FIG. 3 in more detail. As shown in FIG. 4, the ONU 10 includes an upper communication processing unit 11 that performs communication processing, a return point control unit 12, a lower communication processing unit 13 that performs communication processing, and an interface switching unit 14. The folding point control unit 12 includes a folding point extraction unit 12a and a folding point setting unit 12b. The interface switching unit 14 includes a data block 15, a control block 16, a separation block 17, and a defining block 18 as processing blocks for performing signal processing. In FIG. 4, the upper communication processing unit 11, the turn-back point control unit 12, the lower communication processing unit 13, and the interface switching unit 14 are shown as separate processing blocks. It may be configured. In each figure, the data signal is indicated by a solid arrow line, and the control signal is indicated by a broken arrow line.

  The upper communication processing unit 11 performs data transmission / reception processing with the OLT 20 shown in FIG. Therefore, the upper communication processing unit 11 performs a series of data processing on the data received from the lower communication processing unit 13 as a transmission function unit. The processing as the transmission function unit executed by the higher-level communication processing unit 11 includes, for example, error check, data string extraction, data string storage, data string generation, and conversion from an electric signal to an optical signal (electric / optical conversion). And output of an optical signal to the transmission medium 1. The host communication processing unit 11 performs a series of data processing on the data received from the OLT 20 as a reception function unit. The processing as the reception function unit executed by the host communication processing unit 11 includes, for example, reception of an optical signal from the transmission medium 1, conversion from an optical signal to an electric signal (optical / electrical conversion), generation of a data string, and data string Storage, data string extraction, and error checking.

  When the host communication processing unit 11 receives the loopback test start notification data transmitted from the OLT 20, the host communication processing unit 11 performs the following operation without performing the series of data processing. The upper communication processing unit 11 transfers the received return test start notification data to the return point extraction unit 12 a in the return point control unit 12. The return point extraction unit 12a extracts information indicating the return point from the transferred return test start notification data, and sends the extracted information to the return point setting unit 12b. The return point setting unit 12b sets the return point based on the received information indicating the return point. Note that a configuration may be adopted in which extraction of information indicating the return point in the return test start notification data is performed by the upper communication processing unit 11 and the extracted data string is transferred to the return point extraction unit 12a.

  For example, when the return point is set in the communication terminal 30 from the return point setting unit 12b, the upper communication processing unit 11 waits for a preparation response from the return point setting unit 12b after the completion of the return point setting. A preparation response is transmitted to the OLT 20. The loopback test data received from the OLT 20 after transmitting the preparation response is transferred from the upper communication processing unit 11 to the lower communication processing unit 13 as it is, and the transmission direction of the loopback test data is changed from the downward direction at the loopback point in the communication terminal 30. Switching to the upstream direction, it is returned as upstream data. For example, when the return point is set in the upper communication processing unit 11, the upper communication processing unit 11 sets the return point and transmits a preparation response to the OLT 20 after the setting is completed.

  The return point extraction unit 12 a of the return point control unit 12 extracts information indicating the return point from the return test start notification data transferred from the higher-level communication processing unit 11. As described above, the upper communication processing unit 11 may extract the information indicating the turn-back point. In that case, the folding point extraction unit 12a in the folding point control unit 12 can be omitted. Further, the return point extraction unit 12a notifies the return point setting unit 12b of information indicating the extracted return point.

  The return point setting unit 12b sets a return point for the functional block (such as the upper communication processing unit 11, the lower communication processing unit 13, or the communication terminal 30) selected according to the notified information indicating the return point. Send instructions. When transmitting an instruction for setting a return point to the communication terminal 30, if it is determined that there is no interface with the communication terminal 30, the return point setting unit 12b instructs the interface switching unit 14 to include a regulation block 18 and a control block. The separation block 17 separating 16 is instructed to connect the regulation block 18 and the control block 16, and is connected to the communication terminal 30 via the control block 16 and the regulation block 18 ( After establishing the control signal interface (which will be described as step S5 in FIG. 8 to be described later), an instruction for setting the turn-back point is transmitted through this interface. When the return point setting unit 12b receives the preparation response transmitted from the communication terminal 30 after the instruction to set the return point, the return point setting unit 12b transfers the preparation response to the higher-level communication processing unit 11 and sets the separation block 17 in the connected state. In this case, the interface switching unit 14 is instructed to cancel the connection state and to make the specified data signal interface usable. On the other hand, if it is determined that there is no interface for transferring the loopback test data to the regulation block 18, the separation block 17 that separates the regulation block 18 and the data block 15 is brought into a connected state, and the data block 15 and the regulation block 18 are connected. After establishing an interface (an interface for other data signals) connected to the communication terminal 30 via (and will be described as step S6 in FIG. 8 described later), the loopback test data is transferred.

  When the separation block 17 is brought into the disconnected state after the loopback test, the loopback point setting unit 12b instructs the communication terminal 30 to cancel the loopback point setting in the same procedure as when the loopback test is started. Thereafter, the host communication processing unit 11 transmits a preparation response to the OLT 20 after waiting for a preparation response from the return point setting unit 12b after canceling the setting of the return point.

  The lower communication processing unit 13 performs data transmission / reception processing with the communication terminal 30. In general, the lower communication processing unit 13 is configured by a PHY (physical layer) circuit. However, when the ONU 10 is an MSA interface module such as a GBIC module or an SFP module, the lower communication processing unit 13 is used. May not exist as an independent functional block. Thus, the upper communication processing unit 11, the interface switching unit 14, and the lower communication processing unit 13 do not necessarily have to be independent and separate functional blocks, and may be configured by one functional block. Note that the one function block may include the turn-back point control unit 12. The lower communication processing unit 13 transmits the downlink data received from the upper communication processing unit 11 to the communication terminal 30. Further, the lower communication processing unit 13 outputs the uplink data received from the communication terminal 30 to the higher communication processing unit 11. However, when switching of the data line used in the interface switching unit 14 (interface switching) is performed during transmission / reception of the loopback test data, the lower-level communication processing unit 13 is not the communication terminal 30 but the data In some cases, data is exchanged with the block 15. When the lower communication processing unit 13 receives a return point setting instruction from the return point setting unit 12b, the lower communication processing unit 13 receives the return test data as downlink data transferred from the higher communication processing unit 11. It returns at the loopback point set in the lower communication processing section, and the returned loopback test data is transferred to the upper communication processing section 11 as uplink data.

  The interface switching unit 14 includes a data block 15, a control block 16, a separation block 17, and a defining block 18 as processing blocks. The data block 15 is a processing block for realizing transmission / reception of data signals between the lower-level communication processing unit 13 and the communication terminal 30, and the data signal line of the ONU 10 via the separation block 17 and the regulation block 18. The data signal line of the communication terminal 30 is connected. Further, the data block 15 connects the clock signal line of the ONU 10 and the clock signal line of the communication terminal 30 via the separation block 17 and the defining block 18 when necessary. If the data block is defined in the defining block 18, the data block 15 shown in FIG. 4 can be omitted.

  The control block 16 is a processing block for realizing transmission / reception of control signals between the turn-back point setting unit 12b and the communication terminal 30, and the control signal line of the ONU 10 via the separation block 17 and the regulation block 18 The control signal line of the communication terminal 30 is connected. Further, when necessary, the control block 16 connects the clock signal line of the ONU 10 and the clock signal line of the communication terminal 30 via the separation block 17 and the defining block 18. In the control signal line, for example, I2C (Inter-Integrated Circuit), MDIO (Management Data Input / Output) / MDC (Management Data Clock), and UART (Universal Asynchronous Receive Control control signals such as Universal Transmit Control) The Similar to the data block 15, when the control signal line is defined in the defining block 18, the control block 16 shown in FIG. 4 can be omitted.

  The separation block 17 selectively performs separation or connection between the definition block 18 and the data block 15 and selectively performs separation or connection between the definition block 18 and the control block 16. For example, the separation block 17 includes a switch configuration unit that can switch (switch) a transmission path and a buffer such as a transistor.

  The definition block 18 is connected when, for example, the ONU 10 is an MSA interface module such as a GBIC module and an SFP module, and when the interface with the communication terminal 30 is defined by a standard such as SFF (Small Form Factor). This block is for satisfying the pin assignment and function of the unit, the logic fixing method and the termination method, and mainly performs processing for pulling up, pulling down, or opening the potential of the signal line. The defining block 18 sets a defined pin assignment and function for each pin of the connecting portion (connector). However, when the defining block 18 is connected to the data block 15 or the control block 16 by the separation block 17, the defining block 18 transmits a data signal or a control signal. That is, when the separation block 17 is in the separation state, the regulation block 18 realizes a predetermined regulation interface (a prescribed data signal interface), and when the separation block 17 is in the connection state, A part of the regulation is changed to realize another data signal interface that enables transmission of a data signal or a control signal interface that enables transmission of a control signal.

  FIG. 5 is a block diagram illustrating a configuration example of the OLT 20 according to the first embodiment. The OLT 20 includes a failure determination unit 21 and a lower communication processing unit 22. Note that the OLT 20 normally includes a higher-level communication processing unit for transmitting data to the SNI (application Server Network Interface), but is not shown in FIG. 5 because it is a functional block not directly related to the present invention.

  The failure determination unit 21 determines a failure or abnormality from information on the upper and lower data processed by the lower communication processing unit 22, for example, the number of frame errors. This determination requires several parameters such as the number of frame errors and the frame error observation time, but the necessary parameters are not particularly limited. Further, in the OLT 20, the above determination is not performed, and the communication terminal 40 that is an external device may determine an abnormality such as a failure or a failure, and may acquire detection information (determination information) such as a failure or a failure from the external device. . In this case, the OLT 20 recognizes the presence of a failure or failure based on the determination information from the communication terminal 40. When it is determined that there is a failure or failure, the failure determination unit 21 transmits an instruction for starting a loopback test or loopback test data to the lower-level communication processing unit 22.

  The lower communication processing unit 22 performs data transmission / reception processing with the ONU 10. Therefore, the lower-layer communication processing unit 22 functions as a transmission / reception function unit such as data error check, data string extraction, data string storage, data string generation, electrical / optical conversion, and input / output with the transmission medium 1. Execute.

  When the lower communication processing unit 22 receives an instruction to start the loopback test from the failure determination unit 21, the lower communication processing unit 22 performs the following operation without performing the data processing. First, the lower-layer communication processing unit 22 transmits, to the ONU 10, return test start notification data for notifying that the return test is started. In the return test start notification data, information indicating a return point is included as necessary. The lower-layer communication processing unit 22 transmits the loopback test data as predetermined test data when receiving a preparation response from the ONU 10 after transmitting the loopback test start notification data. After transmitting the loopback test data, the OLT 20 waits for arrival of loopback test data returned from the loopback point during a predetermined waiting time, and determines whether or not the failure site has been received based on whether or not the loopback test data is returned. Is identified. After specifying the faulty part, the OLT 20 transmits to the ONU 10 return test end notification data for notifying the end of the return test.

  FIG. 6 is a block diagram illustrating a configuration example of the communication terminal 30 according to the first embodiment. The communication terminal 30 includes an upper communication processing unit 31, a return point control unit 32 including a return point setting unit 34, and a lower communication processing unit 33. The upper communication processing unit 31 performs data transmission / reception processing with the ONU 10. As a transmission function, the upper communication processing unit 31 performs priority control and bandwidth control on the data received from the lower communication processing unit 33 and outputs the data to the transmission medium 2. When the upper communication processing unit 31 is a PHY circuit, the upper communication processing unit 31 has a function as a PHY, and the upper communication processing unit 31 may be the same processing block as the lower communication processing unit 33. . On the other hand, the upper communication processing unit 31 realizes a function of receiving data from the transmission medium 2 and outputting the received data to the lower communication processing unit 33 as a reception function. Even in this case, when the upper communication processing unit 31 is a PHY circuit, the upper communication processing unit 31 may be the same processing block as the lower communication processing unit 33.

  When the upper communication processing unit 31 receives an instruction for setting the return point from the ONU 10, the following operation is performed. When the return point designation destination is other than the upper communication processing unit 31, the upper communication processing unit 31 transfers a return point setting instruction to the return point control unit 32, and sets the return point via the return point setting unit 34. To do. After the return point is set, a preparation response is sent to the ONU 10 to notify the completion of preparation after waiting for a preparation response from the return point setting unit 34. When the return point is designated within the higher-level communication processing unit 31, the prepared return point is set, and then a preparation response is sent to the ONU 10. After the preparation response, the loopback test data is returned from the downlink direction to the uplink direction at the loopback point. When the loopback point is set in the lower communication processing unit 33, the loopback test data is switched from the downlink direction to the uplink direction at the loopback point and returned. After the loopback test, the communication terminal 30 cancels the loopback point according to the instruction from the ONU 10 in the same procedure as when the loopback test is started.

  FIG. 7 is a block diagram illustrating a configuration example of the communication terminal 40 connected to the OLT 20 according to the first embodiment. As illustrated in FIG. 7, the communication terminal 40 includes a failure notification unit 41. The failure notification unit 41 determines a failure based on the transmission / reception data of the OLT 20 and notifies the OLT 20 of determination information (detection information) obtained by this determination via the transmission medium 3. The communication terminal 40 is, for example, a monitoring device (station building device) that monitors the entire system installed in the station building.

  FIG. 8 is a sequence diagram illustrating an example of the failure identification method according to the first embodiment. FIG. 8 is a diagram illustrating the operation of the communication system according to the first embodiment and the operation of the ONU 10 according to the first embodiment. According to the operation shown in FIG. 8, it becomes possible to specify a failure part on the side of the slave station device including the communication terminal 30 from the station building device such as the OLT 20 or the communication terminal 40, and therefore, when an abnormality such as a failure or a failure occurs. Can improve the efficiency of recovery work.

  In the failure identification method shown in FIG. 8, a loopback test process 61 and a loopback test end process 63 are performed. First, when the communication terminal 40 detects the presence of a failure, the communication terminal 40 transmits detection information (failure notification) that causes the OLT 20 to make a failure (step S1). When the OLT 20 receives a failure notification or does not receive a failure notification from the communication terminal 40 but the OLT 20 detects the presence of a failure, the OLT 20 determines that there is a failure in the communication system (step S2). . After step S2, the OLT 20 transmits the return test start notification data for notifying the start of the return test to the ONU 10 (step S3).

  When receiving the loopback test start notification data in step S3, the ONU 10 extracts information indicating the loopback point from the loopback test start notification data as necessary (step S4). Here, a case where the turn-back point is designated as a point in the communication terminal 30 will be described. The ONU 10 switches the interface used for communication with the communication terminal 30 in order to notify the communication terminal 30 of the return point (step S5), and then the switched interface (for example, the control shown in FIG. 4). The communication terminal 30 is instructed to set the return point using the signal interface. When there is no need to switch the interface, the ONU 10 omits the interface switching operation. When receiving the preparation response (preparation completion response signal) from the communication terminal 30, the ONU 10 switches the interface to be used again so that the loopback test data can be transferred to the communication terminal 30 ( Step S6). Details of the interface switching method will be described later. After the interface switching (for example, after switching to another data signal interface shown in FIG. 4), the ONU 10 prepares a response (a preparation completion response signal) for notifying the OLT 20 that the preparation for the loopback test is completed. ) Is transmitted (step S7).

  When the OLT 20 receives a preparation response from the ONU 10 in step S7, the OLT 20 transmits return test data to the ONU 10 (step S8). The loopback test data is received by the ONU 10, then transferred to the communication terminal 30 through the interface set in step S6, looped back at the loopback point, and returned to the OLT 20 through the ONU 10 (step S9). The OLT 20 waits for reception of the loopback test data during the waiting time T1 from the step S8, and when receiving the loopback test data returned in the step S9, the failure part of the communication terminal 30 is on the side farther from the loopback point. It is determined that it exists (that is, the failure part is specified) (step S10).

  When the OLT 20 identifies the faulty part (step S10), the OLT 20 transmits the return test end notification data for notifying the end of the return test to the ONU 10 (step S11). When the ONU 10 receives the loopback test end notification data transmitted in step S11, the ONU 10 issues a loopback point release instruction by the same processing as the processing shown in steps S5 to S7, and the state before the test is started by switching the interface. (Steps S12 to S14). However, if the interface to be used is switched to the other data signal interface shown in FIG. 4 in step S6, the data signal interface to be used is changed to the specified data signal interface in step S12. There is a need to switch back and to enable the control signal interface.

  FIG. 9 is a flowchart showing the turning point setting process and the interface switching process in the ONU 10 according to the first embodiment. After receiving the return test start notification data from the OLT 20, the return point extraction unit 12a extracts the return point and determines whether the return point is inside the communication terminal 30 (step S41). When the return point is inside the communication terminal 30, the return point extraction unit 12a notifies the return point setting unit 12b of information indicating the return point (turnback point information) (step S42). In step S41, the return point setting unit 12b sets a return point when the return point is located outside the communication terminal 30, for example, the ONU 10, based on the notified return point information (steps S51 and S52). ).

  If it is determined in step S41 that the return point is inside the communication terminal 30, the return point setting unit 12b determines whether the control signal interface needs to be switched (step S43). As an example, when the ONU 10 interface conforms to SFF, the control signal interface is only I2C. Therefore, when setting a return point via I2C, the determination in step S43 is unnecessary (NO). When the upper communication processing unit 31 or the lower communication processing unit 33 of the communication terminal 30 is a PHY circuit and wants to use MDIO / MDC, the determination in step S43 is necessary. (YES) is selected (direct control is selected). When it is determined that the interface needs to be switched, the turn-back point setting unit 12b instructs the interface switching unit 14 to switch the interface (step S44). After the control signal interface is established (step S45), the return point setting unit 12b instructs the communication terminal 30 to set the return point (step S46). After receiving the preparation response from the communication terminal 30 (step S47), the return point setting unit 12b next determines whether or not it is necessary to switch the data signal interface (step S48). Normally, since the data signal interface is not provided, the determination in step S48 is unnecessary (NO). However, if it is determined that it is necessary (YES), the procedure is the same as that of the control signal interface. The data signal interface is switched to another data signal interface (steps S49 and S50). In the first embodiment, the turn-back point control unit 12 and the upper communication processing unit 11 are described as separate blocks, but these may be configured as one block.

  Next, the interface switching operation of the first embodiment will be described. FIGS. 10A and 10B are diagrams illustrating a configuration example for realizing interface switching of the interface switching unit 14 in the ONU 10 according to the first embodiment. According to the interface switching operation of the first embodiment shown in FIGS. 10A and 10B, an interface change (for example, a change to the control signal interface) occurs during the loopback test. Before and after, the interface for specified signals (specified data signals) can be put into use.

  As shown in FIGS. 10A and 10B, in the ONU 10, when the interface switching unit 14 performs interface switching, for example, as shown in FIG. The interface switching unit 14 selectively inputs a control signal or a specified signal via the control block 16 to the defining block 18 by opening the transistor emitter or switching from pull-up to pull-down. to enable. That is, the interface switching unit 14 switches the interface to be used to either the control signal interface or the specified data signal interface. As shown in FIG. 10A, when the regulation block 18 performs processing such as pull-up and pull-down, the interface used by the interface switching unit 14 can be controlled by simply turning on the control input of the separation block 17. Can be switched to an interface. On the other hand, when the regulation block 18 has not only the termination processing as described above but also some processing function, the function of the regulation block 18 is turned off simultaneously with the process of turning on the control input of the control block 16. Processing is required. For example, in the case of the ONU 10 compliant with the SFF standard, a pull-up or pull-down termination process is defined for a function that is not used or a pin in the interface with the communication terminal 30. The realization method described as FIG. 10A assumes such a case. FIG. 10B shows a case where the separation block 17a is configured by a switch. When the switch of the separation block 17a is turned on or off, the interface switching unit 14 transmits the control signal transmitted to the regulation block 18 via the control block 16a and the separation block 17a, and the regulation block 18 via the separation block 17a. Any of the prescribed signals to be transmitted is selectively transmitted to the communication terminal 30.

  In the first embodiment, as an example, the separation block 17 has a configuration using a buffer such as a transistor and the separation block 17a has a configuration using a switch. However, the configuration of the separation block is not limited thereto. The separation block 17 or 17a is a function for selecting one or more types of control signal line interfaces and one or more types of data signal line interfaces to be used for communication with the communication terminal 30. If it is the structure which has, it will not specifically limit.

  As described above, in the first embodiment, the ONU 10 includes the regulation block 18, the separation block 17, the control block 16, and the data block 15, and controls the regulation block 18 and the control during the loopback test for identifying the faulty part. By separating / connecting the block 16 or the regulation block 18 and the data block 15 by the separation block 17 (that is, having a plurality of switchable interfaces), the ONU 10 and the communication connected to the ONU 10 Control signals can be exchanged with the terminal 30. As a result, the ONU 10 can identify (determine) the failure site from the communication terminal 30 during the loopback test. From the above, even when one or more communication terminals are connected to the ONU 10, it is possible to specify the failed part, so that recovery can be efficiently performed.

<< Embodiment 2 >>
FIG. 11 is a sequence diagram illustrating an example of the failure identification method according to the second embodiment of the present invention. 11, processing steps that are the same as or correspond to the processing steps shown in FIG. 8 (Embodiment 1) are denoted by the same reference numerals as those in FIG. The configuration of the communication system and the ONU 10 that can implement the failure identification method of the second embodiment is basically the same as that of the first embodiment. Therefore, in the description of the second embodiment, FIG. 3 to FIG. 7 are also referred to.

  In the first embodiment, as shown in FIG. 8 as the loopback test processing 61 (steps S1 to S10), the OLT 20 receives the loopback test data returned from the loopback point of the communication terminal 30 within the waiting time T1. As shown in FIG. 8 as the loopback test end process 63 (steps S11 to S14), the case where the process for the loopback test end is executed has been described. In contrast, in the second embodiment, the OLT 20 returns from the return point of the communication terminal 30 within the standby time T1, as shown in FIG. 11 as the first return test processing 71 (steps S1 to S8 and S10a). 11 is not received, and as shown in FIG. 11 as the second loopback test process 72 (steps S3a, S5a to S9a, and S10), the OLT 20 returns the loopback point of the communication terminal 30 within the waiting time T1. A case will be described in which the loopback test data returned from is received and processing for loopback test end is executed as shown in FIG. 11 as loopback test end processing 73 (steps S11 to S14).

  In the second embodiment, the processing from steps S1 to S8 shown in FIG. 11 is the same as the processing from steps S1 to S8 shown in FIG. However, in FIG. 11, when the OLT 20 transmits the loopback test data in step S8, the OLT 20 cannot receive the loopback test data returned within the waiting time T1, and determines that there is no loopback test data (step The case where S10a) is performed is illustrated. When the OLT 20 recognizes that the return test data is not returned from the communication terminal 30 (step S10a), the OLT 20 again notifies the ONU 10 to switch the data signal interface to another data signal interface. Data is transmitted (step S3a).

  The ONU 10 receives the loopback test data instructing to switch the interface for the data signal from the OLT 20, and the loopback point setting unit 12b determines that switching to the data signal interface is necessary (step S5a) (FIG. 9 in step S48). Note that the loopback test start notification data may be data defined in another command frame.

  When the ONU 10 receives not the loopback test data indicating the end of the loopback test but the loopback test start data from the OLT 20, the ONU 10 switches the data signal interface by the same process as the processes shown in steps S49 and S50 of FIG. In step S6a), a preparation response is transmitted to the OLT 20 (step S7a).

  Next, the ONU 10 performs a loopback test. The operation of the ONU 10 during this loopback test (S8a and S9a in FIG. 11) is the same as the operation of the ONU 10 of the first embodiment (S8 and S9 in FIG. 8). However, in the second embodiment, the lower communication processing unit 13 of the ONU 10 needs to transfer data to the data block 15 after switching instead of the prescribed data signal interface (ie, the other shown in FIG. 4). This is different from the case of the first embodiment in which data is transferred to a prescribed block. In Embodiment 2, the communication terminal 30 also needs to select the data input path so that the upper communication processing unit 31 of the communication terminal 30 is connected to the data block 15 after switching in the ONU 10. .

  In the case of the second embodiment, unlike the case of the first embodiment, when the data signal interface is changed from the specified data signal interface to another data signal interface (step S5a), communication is usually performed. Notification to the terminal 30 is required. In that case, it is necessary to notify the communication terminal 30 using the control signal interface between the ONU 10 and the communication terminal 30. Therefore, the ONU 10 according to the second embodiment needs to execute the same processing steps as the processing steps S44 to S50 shown in FIG. 9 instead of the processing steps S48 to S50 in FIG.

  As described above, the ONU 10 according to the second embodiment provides a data signal interface between the ONU 10 and the communication terminal 30 when the OLT 20 does not return the return test data during the first return test (S8 in FIG. 11). By switching from the specified data signal interface to another data signal interface via the data block 15, the return test is performed even when a failure occurs in the specified data signal interface and the return test data is not returned. It is possible to identify (determine) that the faulty part is in the specified data signal interface used during the first loopback test. As described above, according to the second embodiment, compared with the first embodiment, it is possible to specify a more detailed failure part.

<< Embodiment 3 >>
FIG. 12 is a sequence diagram illustrating an example of the failure identification method according to the third embodiment of the present invention. 12, processing steps that are the same as or correspond to the processing steps shown in FIG. 8 (Embodiment 1) are given the same reference numerals as those in FIG. The configuration of the communication system and ONU 10 that can implement the failure identification method of the third embodiment is basically the same as that of the first embodiment. Therefore, in the description of the third embodiment, FIGS. 3 to 7 are also referred to.

  In the first embodiment, as shown in FIG. 8 as the loopback test processing 61 (steps S1 to S10), the OLT 20 receives the loopback test data returned from the loopback point of the communication terminal 30 within the waiting time T1. As shown in FIG. 8 as the loopback test end process 63 (steps S11 to S14), the case where the process for the loopback test end is executed has been described. On the other hand, in the third embodiment, as shown in FIG. 12 as the first loopback test process 81 (steps S1 to S8 and S10b), the OLT 20 starts from the loopback point of the communication terminal 30 within the standby time T1. The returned loop test data is not received, and the second loop test process (including link status change) 82 in FIG. 12 (steps S3b, S5b, S6a, S31 to S34, S5c to S7c, and S8b to S10c) As shown in FIG. 12, the OLT 20 receives the return test data returned from the return point of the communication terminal 30 within the waiting time T1, and as shown in FIG. 12 as the return test end process 83 (steps S11 to S14), A case where the process for ending the loopback test is executed will be described.

  In the third embodiment, the processing from steps S1 to S8 shown in FIG. 12 is the same as the processing from steps S1 to S8 shown in FIG. In the third embodiment, the processing from step S11 to S14 shown in FIG. 12 is the same as the processing from step S11 to S14 shown in FIG. However, as shown in FIG. 12, the failure identification method according to the third embodiment cannot receive the loopback test data in the first test 81, and determines that there is no loopback test data (step S10b). The second test 82 is different from the method of the first embodiment in that the second test 82 is performed.

  In the third embodiment, after the OLT 20 determines that there is no loopback test data (step S10b), the OLT 20 switches the interface to be used again to the control signal interface (control block 16 in FIG. 4) for the ONU 10. Return test start notification data for instructing the operation is transmitted (step S3b). Note that the notification data transmitted by the OLT 20 in step S3b is not necessarily data having the same content as the return test start notification data in step S3, and may be notification data defined in a different command frame.

  As shown in FIG. 12, when receiving the return test start notification data from the OLT 20 (step S3b), the ONU 10 switches to the control signal interface (from steps S5b to S7b in FIG. 12). After switching the interface to be used to the control signal interface, the ONU 10 establishes a link state with respect to the communication terminal 30 via the return point setting unit 12b, the control block 16, the separation block 17, and the regulation block 18. Confirmation is performed (steps S31 and S32). Specifically, the ONU 10 is configured such that when the upper communication processing unit 31 and the lower communication processing unit 33 of the communication terminal 30 are PHY circuits, MDI (Medium Dependent Interface) or MDIX (Medium Dependent Interface Crossover) or link speed The link state such as 10 Mbps, 100 Mbps, or 1000 Mbps (that is, 10/100/1000 Mbps) is confirmed. However, the confirmation items are not limited to these. Note that the ONU 10 determines whether or not the link state between the ONU 10 and the communication terminal 30 needs to be changed (steps S31 and S32). The link state may be confirmed, and the result of this confirmation may be held in a memory (not shown).

  The ONU 10 (for example, the control unit provided in the ONU 10) is connected to the lower communication processing unit 13 of the ONU 10 even when either the upper communication processing unit 31 or the lower communication processing unit 33 of the communication terminal 30 is not a PHY circuit. The link state with the upper communication processing unit 31 of the communication terminal 30 is confirmed (steps S31 and S32). At this time, if the link state with the lower communication processing unit 33 of the communication terminal 30 rather than the upper communication processing unit 31 of the communication terminal 30 affects the data transmission, the ONU 10 performs the lower communication processing unit 33 of the communication terminal 30. Check the link status with. When confirming the link state with the communication terminal 30, the ONU 10 directly controls the upper communication processing unit 31 or the lower communication processing unit 33 of the communication terminal 30, and the upper communication processing unit 31 or the lower communication processing of the communication terminal 30. There are cases where the unit 33 is indirectly controlled.

  As a result of checking the link state, the ONU 10 detects the mismatch of the link speeds, the upper communication processing unit 31 or the lower communication processing unit 33 of the communication terminal 30 or the lower communication processing unit 13 of the ONU 10 The communication terminal 30 is instructed to change the link speed (step S33), and the communication terminal 30 transmits a preparation response informing the completion of the change to the ONU 10 (step S34). When the link state between the ONU 10 and the communication terminal 30 is held in the memory in advance, the ONU 10 does not need to confirm the link state here, but stores the link state confirmation information. The link condition may be set based on After the link speed is changed, the ONU 10 switches the interface to be used to the control signal interface (control block 16 in FIG. 4) and switches to the data signal interface (steps S5c to 7c). The OLT 20 transmits the loopback test data (step S8b), receives the returned loopback test data (step S9b), and specifies the failure part based on the received data (step S10c). In this step 10b, the OLT 20 determines a mismatch between the link speeds of the ONU 10 and the communication terminal 30 when a return test data is returned during the second return test 82. For example, when the ONU 10 and the communication terminal 30 transmit data via an interface such as SGMII (Serial Gigabit Media Independent Interface), the transmission rate of the data line is determined by auto-negotiation during data transmission. Auto-negotiation is a function that, for example, detects the communication speed of the connected devices and the supported communication mode by exchanging a prescribed pulse signal, and selects the optimum link condition based on the detection result. . As another method for realizing auto-negotiation, there is a method by exchanging register information in a register indicating a link state. For example, as a sequence in this method, first, one device transmits register information to the other device. Next, the other device changes the communication speed based on the received register information, and notifies one device of the completion of the change of the communication speed. Then, one device recognizes the completion of the communication speed change.

  Since each of the ONU 10 and the communication terminal 30 is a separate device, if any of the ONU 10 and the auto-negotiation function is disabled, the ONU 10 and the communication terminal 30 may not be aware of this and a link mismatch may occur. In the third embodiment, since it becomes possible to prepare a control signal interface between the ONU 10 and the communication terminal 30, it is possible to match the link speeds in the above case. In the third embodiment, for example, when auto-negotiation using a data line as a data signal interface is disabled, a control line that is a control signal interface different from the data signal interface is used. It is possible to match the link speed.

  As described above, the ONU 10 of the third embodiment performs the second loopback test (when the loopback test data is not returned to the OLT 20 during the first loopback test (steps S1 to S8 and S10b)). Steps S3b to S9b and S10c) are performed. In the second loopback test, the OLT 20 switches the interface used between the communication terminal 30 to the control signal interface, and matches the link speeds of the ONU 10 and the communication terminal 30 so that the link during the first loopback test is performed. It becomes possible to isolate the state mismatch. For this reason, according to the third embodiment, only the physical layer can be separated in the first embodiment, but the specific range of the failure part can be expanded.

<Modification>
FIG. 13 is a hardware configuration diagram showing the configuration of the ONU 10 according to the first to third embodiments. 13 includes a memory 91 as a storage device that stores a program as software, and a processor 92 as an information processing unit that executes the program stored in the memory 91. The ONU 10 shown in FIG. 13 shows a specific example of the structure of the slave station apparatus according to the first to third embodiments. The operation of the apparatus shown in FIG. 13 is the same as that of the ONU 10 according to the first to third embodiments.

  When the apparatus shown in FIG. 13 realizes the processing in the ONU 10 of the first to third embodiments, each configuration of the ONU 10 shown in FIG. 3 is such that the processor 92 executes a program stored in the memory 91. Is realized. In addition, in order to implement | achieve each structure of ONU10, the case where it used with the processor 92 and the memory 91 was illustrated, However, A part of each structure of ONU10 is implement | achieved by the processor 92 and the memory 91, and another part is a hardware circuit. It may be realized. The ONU 10 and the failure identification method described in the first to third embodiments can be realized by the communication device illustrated in FIG.

  As described above, the slave station apparatus according to the present invention is useful for a communication system that can efficiently identify a failure site.

  DESCRIPTION OF SYMBOLS 1 Transmission medium (optical cable), 2, 3 Transmission medium, 10 Slave station apparatus (ONU), 11 Upper communication processing part, 12 Folding point control part, 12a Folding point extraction part, 12b Folding point setting part, 13 Lower communication processing part , 14 interface switching unit, 15 data block, 16 control block, 17 separation block, 18 regulation block, 20 master station device (OLT), 21 failure determination unit, 22 lower communication processing unit, 30 communication terminal, 31 upper communication processing unit 32 Return point control unit, 33 Lower communication processing unit, 34 Return point setting unit, 40 Communication terminal, 41 Failure notification unit.

Claims (10)

A slave station device that communicates with a master station device via a transmission medium and communicates with a communication terminal,
An interface switching unit that has a plurality of interfaces for communication with the communication terminal, and performs interface switching for setting an interface to be used to one of the plurality of interfaces;
A loopback point control unit for setting a loopback point at which loopback test data transmitted from the master station device is looped back,
When the slave station apparatus receives the loopback test start notification data for notifying the start of the loopback test from the master station apparatus, the loopback point control unit sets the loopback point,
The interface switching unit performs the interface switching according to the set turn-back point when the set turn-back point is set in the communication terminal, and then the preparation for the turn-back test is completed. Send a preparation response to notify the master station device,
When the set turn-back point is set in the communication terminal, the slave station device is a data signal interface that is the interface set by the interface switching when the return test data is received. And transmitting the received loopback test data to the loopback point using a slave station device.   After the slave station device receives the loopback test start notification data from the master station device, the interface switching unit performs the interface switching and sets the interface to be used as a control signal interface among the plurality of interfaces. The slave station apparatus according to claim 1, wherein the return point control unit sets the return point using the control signal interface.   When the slave station apparatus receives loopback test end notification data for notifying the end of the loopback test from the master station apparatus, the loopback point control unit cancels the set loopback point. The slave station apparatus according to claim 1 or 2.   The slave station device uses the data signal interface set by the interface switching, arrives at the set return point, returns the return test data returned at the set return point, The slave station apparatus according to any one of claims 1 to 3, wherein the slave station apparatus is returned to the master station apparatus. When the master station device does not receive the return test data sent back from the set return point within a predetermined waiting time, the slave station device receives another return test from the master station device. Receive start notification data,
The interface switching unit of the slave station device that has received the other loopback test start notification data, when the set loopback point is set in the communication terminal, according to the set loopback point The interface is switched, and then a preparation response is sent to the master station device to notify that the preparation for the loopback test is completed,
In the case where the set turn-back point is set in the communication terminal, the slave station device receives another data signal that is the interface set by the interface switching when receiving the turn-back test data. The slave station apparatus according to any one of claims 1 to 3, wherein the received loopback test data is transmitted to the loopback point using a communication interface. When the master station device does not receive the return test data sent back from the set return point within a predetermined waiting time, the slave station device receives another return test from the master station device. Receive start notification data,
The interface switching unit of the slave station device that has received the other loopback test start notification data, when the set loopback point is set in the communication terminal, according to the set loopback point The interface is switched, the link state with the communication terminal is confirmed, a process for optimizing the link state with the communication terminal based on the result of the confirmation is performed, and then a preparation for a return test is performed. Sending a preparation response to notify the completion to the master station device;
The slave station device transmits the received return test data to the return point when the return test data is received when the set return point is set in the communication terminal. The slave station apparatus according to any one of claims 1 to 3, wherein The slave station device confirms a link state with the communication terminal at an arbitrary time, and holds the result of the confirmation,
When the master station device does not receive the return test data sent back from the set return point within a predetermined waiting time, the slave station device receives another return test from the master station device. Receive start notification data,
The interface switching unit of the slave station device that has received the other loopback test start notification data, when the set loopback point is set in the communication terminal, according to the set loopback point The interface is switched, a process for optimizing the link state with the communication terminal based on the held link state is performed, and then a preparation response is sent to notify that the preparation for the loopback test is completed. To the master station device,
The slave station device transmits the received return test data to the return point when the return test data is received when the set return point is set in the communication terminal. The slave station apparatus according to any one of claims 1 to 3, wherein The interface switching unit
As the plurality of interfaces, a first data signal interface, a second data signal interface, and a control signal interface are provided,
When setting up the second data signal interface, the first data signal interface is separated,
The slave station device according to claim 1, wherein when setting the control signal interface, the first data signal interface is separated. A slave station device that communicates with the master station device via a transmission medium;
A communication terminal for communicating with the slave station device;
A communication system comprising:
The slave station device is
An interface switching unit that has a plurality of interfaces for communication with the communication terminal, and performs interface switching for setting an interface to be used to one of the plurality of interfaces;
A loopback point control unit for setting a loopback point at which loopback test data transmitted from the master station device is looped back,
When the slave station apparatus receives the loopback test start notification data for notifying the start of the loopback test from the master station apparatus, the loopback point control unit sets the loopback point,
The interface switching unit performs the interface switching according to the set turn-back point when the set turn-back point is set in the communication terminal, and then the preparation for the turn-back test is completed. Send a preparation response to notify the master station device,
When the set turn-back point is set in the communication terminal, the slave station device is a data signal interface that is the interface set by the interface switching when the return test data is received. The received loopback test data is transmitted to the loopback point using a communication system. A communication system comprising a slave station device that communicates with a master station device via a transmission medium and a communication terminal that communicates with the slave station device, wherein the slave station device is used Interface switching for setting the interface to be set to one of a plurality of interfaces for communication with the communication terminal, and a loopback point at which the loopback test data transmitted from the master station apparatus is looped back is set. A failure identification method in the communication system,
A step of setting the return point when the slave station device receives the return test start notification data for notifying the start of the return test from the master station device;
When the set turn-back point is set in the communication terminal, the interface is switched according to the set turn-back point, and then a preparation response is sent to notify that the preparation for the turn-back test is completed. Transmitting to the master station device;
When the set loopback point is set in the communication terminal, when the loopback test data is received, it is received using the data signal interface which is the interface set by the interface switching. Transmitting the returned loopback test data to the loopback point.

Images