JP4620717B2 - Subscriber line terminal equipment and loopback test method - Google Patents

Description

  The present invention relates to a subscriber line terminal device connected to a subscriber line terminal device by an optical fiber, and in particular, a monitoring signal of a subscriber line terminal device or an alarm signal of a subscriber line terminal device is based on priority. The present invention relates to a subscriber line terminal station apparatus to be selected and a subscriber line terminal station apparatus capable of performing a loopback test including a logical layer of the subscriber line terminal station apparatus.

  The present invention also relates to a loopback test method for a subscriber line terminal equipment connected to the subscriber line terminal equipment by an optical fiber, and in particular, a loopback test capable of a test including a logical layer of the subscriber line terminal equipment. Regarding the method.

  Subscriber-based optical communication systems such as FTTH (Fiber to the Home), which draws optical fiber to the user's home, are beginning to spread.

1A and 1B show subscriber line terminal equipment (in-office media converter, hereinafter referred to as “in-house MC (Media Converter)”) and subscriber termination equipment (in-house media converter, hereinafter referred to as “in-house MC”). .) Is a block diagram showing an overall configuration of a subscriber optical communication system. Fig (A) shows an example in which one-home MC2 ₀ is connected to one station MC1, FIG (B) is to enhance the containment of the user, a plurality to one station MC1 In this example, home MCs 2 _{1 to} 2 _n (n is an integer of 2 or more) are connected.

The in-office MC1 is installed in the station building, and the in-house MC2 ₀ , 2 ₁ to 2 _n (hereinafter collectively referred to as “in-house MC2” unless otherwise required) is installed in the user's home.

One port of the in-office MC1 and one port of the in-house MC2 are one single-mode optical fiber 6 ₀ , 6 _{1 to} 6 _n (hereinafter referred to as “optical fiber 6” unless otherwise required to be distinguished) Are collectively connected). In the optical fiber 6, light of different wavelengths is allocated to the downlink (downlink) signal from the in-office MC1 to the in-house MC2, and the uplink (uplink) signal from the in-house MC2 to the in-house MC1. In full duplex bidirectional communication. For example, a wavelength of 1.55 μm is assigned to the downlink, and a wavelength of 1.3 μm is assigned to the uplink. This provides a point-to-point communication service.

The other port of the intra-station MC 1 is connected to a WAN (Wide Area Network) 4 via a UTP (Unshielded Twist Pair) cable 5. The other port of the in-home MC 2 is an example of a user terminal via UTP cables 7 ₀ , 7 _{1 to} 7 _n (hereinafter collectively referred to as “UTP cable 7” unless otherwise required). PCs (Personal Computers) 3 ₀ , 3 _{1 to} 3 _n (hereinafter collectively referred to as “PC3” unless otherwise required). As a result, data from WAN 4 is transferred to PC 3 via in-office MC 1 and in-house MC 2, and data from PC 3 is transmitted to WAN 4 through in-house MC 2 and in-office MC 1.

  The in-station MC1 and the in-house MC2 adopt an optical ether access method, and a main signal (user data) is communicated by a medium access control (MAC) frame based on IEEE802.3.

  On the other hand, the intra-station MC 1 has an interface device with an operation system (OpS) terminal (not shown) for monitoring and control, and is connected to the OpS terminal via this interface device. Then, the OpS terminal performs remote monitoring and remote control of the home MC 2 via the in-office MC 1. In order to perform such remote monitoring and remote control, a control signal is transmitted from the in-station MC1 to the in-house MC2, and a monitoring signal is transmitted from the in-house MC2 to the in-station MC1.

  These control signals and monitoring signals are transmitted by specially defined frames (hereinafter referred to as “OAM (Operation, Administration and Maintenance) frames”).

  As shown in FIGS. 3A and 3B, the control signal includes “LOOP-MCQ” indicating a start request and a cancel request for a loopback test (described later). The monitoring signals include “LOOP-MCS”, “RMT-POWER”, “RMT-FX-LINK”, “RMT-TX-LINK”, and “RMT” as shown in FIGS. -EQP ”is included.

  The monitor signal LOOP-MCS is a signal returned from the home MC2 to the in-station MC1 as a confirmation response (start response or release response) of the control signal LOOP-MCQ. The monitoring signal RMT-POWER is a signal representing the power status (normal / abnormal) of the in-station MC2. The monitoring signal RMT-TX-LINK is a signal representing the state of the UTP cable 7. The monitoring signal RMT-FX-LINK is a signal representing the reception state of the optical signal of the optical fiber 6. The monitoring signal RMT-EQP is a signal that represents the state of the device in the home MC 2. In the following, the monitoring signal indicating the occurrence of abnormality may be referred to as an alarm signal.

  These monitoring signals (alarm signals) are transmitted from the in-house MC 2 to the in-station MC 1 and given from the in-station MC 1 to the OpS.

  On the other hand, the in-station MC 1 also monitors its own state and gives an alarm to the OpS when an abnormality is detected. As shown in FIG. 3D, the alarm given to the OpS when the in-station MC1 detects an abnormality, as shown in FIG. 3 (D), “UPLINK” indicating the link disconnection of the UTP cable 5, “DOWNLINK” indicating the optical link disconnection of the in-station MC1, In addition, there is “EQP” indicating a device failure (memory error or the like) of the in-station MC1.

  As shown in FIG. 3E, alarms detected by the in-home MC 2 include “TXLINK” indicating a link disconnection of the UTP cable 7 and “FXLINK” indicating an optical signal reception abnormality of the optical fiber 6.

  In addition, in order to confirm the normality of the transmission path before service opening when a new home MC2 is installed in the user's home, or to isolate (narrow down) the failure point when a failure occurs, In between, a turn-back test is performed. FIG. 13 is a sequence diagram of a conventional loopback test, and FIG. 2 is a block diagram showing a logical hierarchy model of in-office MC1 and in-home MC2.

  The in-station MC1 has a physical layer (OSI first layer) and a logical layer (MAC layer (lower sublayer of OSI second layer)) as a logical hierarchy model. A maintenance sublayer for maintenance is provided in the physical layer. In particular, the logical layer is provided in a form in which a plurality of in-house MCs 2 are connected to one in-station MC 1.

  A device for executing the processing of each layer is provided individually. For example, a device for executing processing of the physical layer excluding the maintenance sublayer includes an PHY chip that is an integrated circuit element, and a device for executing the processing of the maintenance sublayer is ASIC. (For example, FPGA), and the device for executing the processing of the logic layer is composed of a MAC chip which is an integrated circuit element.

  Similarly, the in-home MC 2 also includes, for example, a PHY chip that executes physical layer processing, an FPGA that executes maintenance sublayer processing, and a MAC chip that executes logical layer processing. The home MC 2 may not have a logical layer. In this case, the MAC chip may be omitted.

  In this loopback test, first, a loopback test start event is given from the OpS terminal to the maintenance sublayer via the interface device of the intra-station MC1. When receiving the loopback test start event, the maintenance sublayer of in-station MC1 transmits a loopback test start request (LOOP-MCQ = 1) shown in FIG. 3B to the home MC2 using the OAM frame. When the home MC 2 receives this, a loop route is formed in the main signal transfer route of the own device, and then a loopback test start response (LOOP-MCS = 1) shown in FIG. Send. Subsequently, test frames in the format shown in FIG. 14 are transmitted and received continuously at a predetermined transmission cycle (interval) between the in-office MC1 and the in-house MC2.

The test frame has a preamble, an SFD (Start of Frame Delimiter), and a test pattern. The test pattern is a PN pattern (for example, PN15 = X ¹⁵ + X ² +1) generated by a pseudo noise (PN) generator (not shown) included in the maintenance sublayer.

  The test frame received by the in-home MC2 is given to the maintenance sublayer of the physical layer, returned, and returned to the in-house MC1.

  The maintenance sublayer of the in-station MC1 checks the test pattern of the test frame returned from the in-house MC2, and counts the number of bits with errors.

  Such transmission / reception of the test frame is repeated for a predetermined time (time set in the timer), and when the test end is notified from OpS, the loopback test ends. Upon completion of the test, a loopback test cancellation request (LOOP-MCQ = 0) shown in FIG. 3B is transmitted from the in-station MC1 to the home MC2 by an OAM frame, and a loopback test cancellation response (LOOP-MCS) shown in FIG. = 0) is transmitted from the home MC2 to the in-station MC1 by an OAM frame.

  Then, the in-station MC1 notifies the OpS of information indicating whether PN synchronization has been established and an error count (total number of error bits) as a test result. Thereby, the conduction check of the physical layer including the optical fiber transmission line 6 is performed.

  In the conventional remote monitoring described above, all of the monitoring signals RMT-EQP, RMT-POWER, etc. transmitted from the home MC2 to the in-station MC1 are given from the in-station MC1 to the OpS, and the alarm signals UPLINK, DOWNLINK monitored by the in-station MC1. Etc. are all given to OpS.

  Therefore, an alarm signal notifying an abnormality that has occurred for the same cause may be given to OpS as a plurality of different alarm signals. For example, if a failure occurs in the optical section between the in-house MC1 and the in-house MC2, an alarm signal RMT-FX-LINK for abnormal optical reception and an out-of-link alarm signal DOWNLINK for the subscriber line port of the in-house MC1 are generated. , Collected in the in-station MC1, notified to the OpS, and displayed. Also, when the power of the home MC2 is cut off, the transmitted optical power of the home MC2 decreases or the UTP side of the home MC2 is disconnected, so the alarm signals DOWNLINK and RMT-TX-LINK are collected in the local MC1 Is notified and displayed on the OpS.

  In this way, the alarm information collected in the MC1 in the station has been reported and displayed to the OpS as it is, so when multiple alarm signals are generated due to one alarm generation cause in the home MC1, the cause is identified. I couldn't.

  In the conventional loopback test, the test frame passes through the physical layer including the maintenance sublayer of the in-station MC1, but does not pass through the logical layer. Therefore, when there is an abnormality in the logical layer device (for example, the MAC chip), this abnormality cannot be detected by the loopback test. In other words, when there is an abnormality in the logical layer device, the user frame in the actual operation passes through the logical layer device even though there is no abnormality in the test using the test frame, so that the user frame cannot communicate. It was.

  Accordingly, a first object of the present invention is to make it possible to specify the cause of an abnormality when an abnormality is detected in remote monitoring.

  A second object of the present invention is to eliminate a useless alarm notified from the intra-station MC to the OpS.

  Furthermore, a third object of the present invention is to enable an entire test combining a physical layer and a logical layer.

  According to the present invention, unnecessary alarm transmission can be suppressed. Further, according to the present invention, the cause of the alarm can be uniquely specified.

  Furthermore, according to the present invention, it is possible to check the status of the device corresponding to the logical layer.

  A subscriber line terminal device according to a first aspect of the present invention is a subscriber line terminal device connected to a subscriber line terminator by an optical fiber, and transmits from the subscriber line terminator through the optical fiber. A receiving unit for receiving a plurality of monitoring signals each representing normality or abnormality of a plurality of monitoring items in the subscriber terminal device, and two or more of the plurality of monitoring signals received by the receiving unit And a selection unit that selects a monitoring signal with a high priority based on a predetermined priority from among the monitoring signals representing the two or more abnormalities.

  According to the first aspect of the present invention, when two or more of a plurality of monitoring signals indicate an abnormality, the priority order is determined based on a predetermined priority among the monitoring signals indicating the two or more abnormalities. A high monitoring signal is selected. Therefore, it is possible to eliminate a useless alarm notification by notifying the selected monitoring signal to OpS or the like. Further, the cause of the abnormality can be uniquely identified by indicating the cause of the abnormality as a monitoring signal having a high priority (ie, the selected monitoring signal).

  In addition, the subscriber line terminal equipment according to the second aspect of the present invention is the subscriber line terminal equipment connected to the subscriber line terminal equipment via an optical fiber, and the normality or abnormality of a plurality of monitoring items in the own equipment is determined. A monitoring unit that monitors and outputs an alarm signal corresponding to a monitoring item in which an abnormality is detected, and the monitoring unit outputs two or more alarm signals respectively corresponding to two or more monitoring items of the plurality of monitoring items Includes a selection unit that selects an alarm signal having a high priority based on a predetermined priority from the two or more alarm signals.

  According to the second aspect of the present invention, as in the first aspect, useless alarm notification can be eliminated by notifying the selected alarm signal to OpS or the like. Further, the cause of the abnormality can be uniquely identified by indicating the cause of the abnormality by the alarm signal having a high priority (that is, the selected alarm signal).

The subscriber line terminal equipment according to the third aspect of the present invention monitors the normality or abnormality of a plurality of monitoring items in its own equipment in the subscriber line terminal equipment connected to the subscriber line terminal equipment by optical fiber. A monitoring unit that outputs an alarm signal corresponding to a monitoring item in which an abnormality is detected, and transmitted from the subscriber line termination device via the optical fiber, and the normality or abnormality of a plurality of monitoring items in the subscriber termination device is detected. A receiving unit that receives a plurality of monitoring signals respectively representing the two or more alarm signals when the monitoring unit outputs two or more alarm signals respectively corresponding to two or more monitoring items of the plurality of monitoring items. If an alarm signal having a high priority is selected from among the signals based on a predetermined priority, and two or more of the plurality of monitoring signals received by the receiving unit indicate an abnormality, Less than A monitoring signal having a higher priority order is selected from the monitoring signals that indicate an abnormality in the system, or the monitoring unit outputs an alarm signal corresponding to at least one monitoring item among the plurality of monitoring items And when at least one of the plurality of monitoring signals received by the receiving unit indicates abnormality, the at least one warning signal and the at least one monitoring signal are selected based on the priority order. And a selection unit that selects an alarm signal or a monitoring signal with a high priority. The third aspect of the present invention also provides the same operational effects as the first and second aspects. It is done.

  According to a fourth aspect of the present invention, there is provided a subscriber line terminal equipment which is connected to a subscriber line termination device via an optical fiber and performs physical layer processing on data communicated via the optical fiber. A layer device, a logical layer device that performs logical layer processing, and a maintenance sublayer device connected to the physical layer device and the logical layer device that executes processing of a maintenance sublayer that forms part of the physical layer The maintenance sublayer device includes a test frame including a payload portion having test data for performing a loopback test with the subscriber line termination device or the physical layer device. The test frame generated and transmitted to the logical layer device and returned from the subscriber line termination device or the physical layer device. A test frame processing unit that receives and inspects from the logical layer device; and transfers the test frame received from the logical layer device to the physical layer device; and the test frame received from the physical layer device A first port unit that transfers to the logical layer device, the logical layer device transfers the test frame from the test frame processing unit to the first port unit, and the test from the first port unit. A second port unit for transferring the frame to the test frame processing unit is provided.

  A loopback test method according to a fourth aspect of the present invention comprises a physical layer device connected to a subscriber line termination device via an optical fiber and performing physical layer processing on data communicated via the optical fiber; , A logical layer device that performs logical layer processing, and a maintenance sublayer device that performs processing of a maintenance sublayer that forms part of the physical layer and is connected to the physical layer device and the logical layer device A subscriber line terminal apparatus loopback test method, wherein the maintenance sublayer apparatus includes a payload portion having test data for performing a loopback test with the subscriber line termination apparatus or the physical layer apparatus. A test frame is generated and transmitted to the logical layer device, and the logical layer device receives the test frame from the maintenance sublayer device. The maintenance sublayer device returns the test frame returned from the subscriber line termination device or the physical layer device to the logical layer device, and transfers the logical layer to the physical layer device. The apparatus further returns the test frame returned from the maintenance sublayer apparatus to the maintenance sublayer apparatus, and the maintenance sublayer apparatus receives and inspects the test frame returned from the logical layer apparatus. .

  According to the fourth aspect of the present invention, a test frame is also transmitted to the logical layer device, and a loopback test is performed via the logical layer device. Therefore, it is possible to perform an entire test combining the physical layer and the logical layer.

  1A and 1B are block diagrams showing the overall configuration of a subscriber optical communication system according to an embodiment of the present invention. Since the details of this figure have already been described in the section of the prior art, the description thereof will be omitted here, and in the following, the detailed configuration of the in-station MC 1 according to the embodiment of the present invention, the processing of alarm notification The processing of the loopback test will be described.

<Internal MC configuration>
FIG. 4 is a block diagram showing a detailed configuration of the intra-station MC 1 according to the embodiment of the present invention.

  The intra-station MC1 is configured by devices corresponding to each layer of the logical layer model of communication shown in FIG. 2 described above, and in this embodiment, as an example, a physical layer device 11 that executes processing of the physical layer excluding the maintenance sublayer, It has a maintenance sublayer device 12 that executes maintenance sublayer processing, a logical layer device 13 that executes logical layer (MAC layer) processing, a CPU 14, and a memory (RAM, ROM) 15.

  The physical layer device 11 is composed of, for example, a general-purpose PHY chip (Fichip). The maintenance sublayer device 12 is composed of, for example, dedicated hardware ASIC (for example, FPGA (Field Programming Gate Array)). The logical layer device 13 is composed of a general-purpose MAC chip, for example.

  These components 11 to 15 are connected to the internal bus 16 and can communicate with each other via the internal bus 16.

  The CPU 14 executes the program stored in the memory 15 and controls the in-station MC1. For example, the CPU 14 detects a memory error, a timer abnormality, etc., and notifies the detected abnormality to the maintenance sublayer device 12 as an alarm EQP (see FIG. 3D).

On the other hand, the physical layer device 11 has N (N is an integer of 2 or more) port portions 1a _{0 to} 1a _N−1 . The port units 1a _{0 to} 1a _N-1 are ports # 0 to ## connected to the in-home MCs 2 # 0 to # N-1 (in-house MC2 ₁ to _{2n in} FIG. 1B) via the optical fiber 6, respectively. N-1 is provided corresponding to each. These port sections 1a _{0 to} 1a _N-1 monitor the state of the optical fiber 6 connected to the port sections 1a _{0 to} 1a _N-1 , and if an abnormality is detected, the maintenance sublayer apparatus 12 sends the information shown in FIG. A monitoring signal RMT-FX-LINK or an alarm DOWNLINK shown in FIG.

The in-station MC 1 is connected to the WAN 4 by a single UTP cable in FIGS. 1A and 1B, but may be connected to the WAN 4 by a plurality of ports and a plurality of UTP cables. Therefore, in FIG. 4, the physical layer device 11, on the other hand, has port units 1 b ₀ to 1 b _M respectively corresponding to M (M is an integer of 2 or more) ports # 0 to # M−1 connected to the WAN 4. _-1 . These port sections 1b _{0 to} 1b _M-1 monitor the state of the UTP cable 5 connected to the port sections 1b _{0 to} 1b _M-1 , and if an abnormality is detected, the port section 1b _{0 to} 1b _M-1 indicates to the maintenance sublayer device 12 as shown in FIG. Notify the alarm UPLINK.

Maintenance sublayer device 12 includes a port portion 2a ₀ ~2a _N-1 respectively corresponding to the port # 0~ # N-1, and the test frame processing unit 2b, and the interface device and not shown OpS (not shown) .

These port sections 2a _{0 to} 2a _N-1 have the same circuit configuration, and have an Ether type identification function, an address replacement function, an FCS (Frame Check Sequence) calculation function, etc., which will be described later.

The port 2a _i (i is an integer from 0 to N-1) of the maintenance sublayer device 12 and the port 1a _i of the physical layer device 11 are connected to each other and can communicate with each other. . The port unit 2a _i gives a control signal given from the OpS via the interface device to the corresponding port unit 1a _i .

On the other hand, the port unit 2a _i includes a monitoring signal (see FIG. 3C) received by the port unit 1a _i from the home MC device #i and an alarm signal detected by the port unit 1a _i itself (see FIG. 3D). ) And collect. The port unit 2a _i processes the collected monitoring signal and alarm signal based on a predetermined priority, and notifies the OpS via the interface device of the processed monitoring signal or alarm signal. The priority and the processing based on the priority will be described later.

  The test frame processing unit 2b generates a test frame used for the loopback test, transmits it to the home MC2, checks the test frame returned from the home MC2, and notifies the OpS of the check result. Details of the loopback test and the test frame will be described later.

The logical layer device 13 includes port units 3a _{0 to} 3a _N−1 corresponding to the ports # 0 to # N−1, respectively. Further, the physical layer device 13 has a port section 3a _L of a port #L (and therefore L ≠ 0 to N-1) different from the ports # 0 to # N-1. These port portions 3a _{0 to} 3a _N-1 have the same circuit configuration, and have an address learning function, a storage register for a set address, and the like.

The port unit 2a _i of the logical layer device 13 port unit 3a _i and maintenance sublayer device are connected to each other, and can communicate with each other. Any _one of the port unit 3ai and the port units 1b _{0 to} 1b _M-1 is connected to each other and can communicate with each other. Further, the test frame processing unit 2b and the port unit 3a _L are connected to each other and can communicate with each other. Furthermore, the port units 3a _{0 to} 3a _N-1 and 3a _L are connected inside the logical layer device 13 and can communicate with each other.

The main signal transmitted from home MC2 # i (user data) is again via port unit 1a _i of the physical layer device 11, port unit 2a _i maintenance sublayer device 12, and a port portion 3a _i of the logical layer device 13 It is given to the physical layer device 11 and is transmitted from the port unit 1b _j (j is an integer from 0 to M−1) to the WAN 4 according to the address. On the other hand, the main signal received from the WAN 4 to the port unit 1b _j of the physical layer device 11 is in accordance with the address, the port unit 3a _i of the logical layer device 13, the port unit 2a _i of the maintenance sublayer device 12, and the physical layer device 11 through the port portion 1a _i, it is transmitted to the home MC2 # i. In this way, communication is performed between the in-home MC 2 # i and the WAN.

  The in-station MC 1 having such a configuration executes alarm notification and loopback test processing according to the embodiment of the present invention. In the following, the alarm notification will be explained first, and then the loopback test will be explained.

<Alarm notification>
From the in-house MC 2 to the in-station MC 1, the monitoring signals include “LOOP-MCS”, “RMT-POWER”, “RMT-FX-LINK”, “RMT-TX” shown in FIGS. -LINK ”and“ RMT-EQP ”are included. The meaning of each signal is as described above. Among these monitoring signals, the monitoring signals RMT-POWER, RMT-FX-LINK, RMT-TX-LINK, and RMT-EQP have a device error in the home MC2. It is used for alarm transmission (alarm signal) to the in-station MC1 in some cases.

  As described above, the monitoring signal is transmitted by the OAM frame. 5A shows the frame format of the OAM frame (notation in the case of 4-bit parallel transmission), and FIG. 5B shows the contents of each bit data constituting the OAM frame. This OAM frame format is a normal OAM frame format.

  The first 7-bit data F0 to F7 are preamble signals. The 1-bit data C0 following the preamble signal is a maintenance signal identifier. When this value is 0, the in-station MC1 and the in-home MC2 identify that this frame is an OAM frame (that is, a maintenance signal frame). be able to.

  The 1-bit data S0 is a control signal LOOP-MCQ indicating a return test start request or cancellation request in the OAM frame transmitted from the in-office MC1 to the in-house MC2, and is returned in the OAM frame transmitted from the in-house MC2 to the in-station MC1. This is the monitoring signal LOOP-MCS that represents the test start response or release response.

  1-bit data S1 is a monitoring signal RMT-POWER for notifying the normality or abnormality of the power supply of the home MC2, and when it is “0”, the power supply is normal, and when it is “1”, the power supply is abnormal. (That is, the power was cut off). The home MC 2 (physical layer device) determines whether the power is normal or abnormal by monitoring the power level.

  1-bit data S2 is a monitoring signal RMT-FX-LINK that notifies LINKUP (normal) or LINKDOWN (abnormal) of optical reception via the optical fiber 6 of the home MC2, and indicates normal when “0”. , “1” indicates that an abnormality occurred in reception. The cause of the abnormality of the optical signal includes the disconnection of the optical fiber 6, the failure of the receiving photodiode in the home MC2, and the failure of the transmitting laser diode in the in-house MC1. The in-home MC 2 (physical layer device) determines whether the optical reception is normal or abnormal by monitoring the level of received light, the symbol error rate, and the like.

  The 1-bit data S3 is a monitoring signal RMT-TX-LINK for notifying LINKUP (normal) or LINKDOWN (abnormal) of UTP7 connecting the home MC2 and PC3. In the case of 1 ″, it indicates that an abnormality has occurred. The home MC 2 (physical layer device) determines whether the UTP 7 is normal or abnormal by monitoring the symbol error rate or the like.

  The 1-bit data S4 is a monitoring signal RMT-EQP for notifying the normality or failure of the home MC2, and indicates “normal” when “0” and indicates that an abnormality has occurred when “1”. The failure of the home MC2 includes, for example, an error in the internal memory of the home MC2, a timer failure, a CPU down, etc., and the home MC2 (CPU or other processing device) monitors these to determine whether it is normal or abnormal. to decide.

  Each bit data is mapped by an MII (Media Independent Interface) (see FIG. 2) between the maintenance sublayer and the physical layer.

  As shown in FIG. 6, this OAM frame is inserted and transmitted in an idle region (IPG: Inter Packet Gap) provided between a user frame carrying a main signal (user data) and the user frame ( In-band transfer). Specifically, the OAM frame is transmitted by replacing the idle pattern in the IPG with the OAM frame. As a result, the OAM frame can be transferred without interfering with the user frame on the same medium as the medium for transmitting the user frame (single mode optical fiber).

  Note that OAM frames may be inserted into all IPGs, or OAM frames may be inserted into every predetermined number of IPGs. In either case, the OAM frame is transmitted / received at a predetermined cycle (time interval).

  In addition, the OAM frame is terminated in the home MC2 and the in-station MC1 by measuring the bit data C0 to C6 in the frame and the frame length, and if it is determined to be an OAM frame, it is terminated. The Therefore, the OAM frame is not transferred to the UTP cables 5 and 7 connected to the in-office MC1 and the in-home MC2, respectively. Even if the PC on the WAN 4 accesses the in-home MC 2 and the in-office MC 1 via the UTP cable 5 or the PC 3 accesses the in-home MC 2 via the UTP cable 7, the OAM frame data is changed. It is not possible.

The OAM frame transmitted from the in-house MC 2 #i to the in-station MC 1 is given from the port section 1 a _i of the physical layer apparatus 11 of the in-station MC 1 to the port section 2 a _i of the maintenance sublayer apparatus 12. Port unit 2a _i the monitoring signal included in the OAM frame, when a LOOP-MCS, or, if not an alarm signal (i.e. RMT-EQP, RMT-POWER, RMT-TX-LINK, and RMT-FX-LINK If this represents normal), these monitoring signals are sent directly to the OpS via the interface device.

On the other hand, when at least one of the monitoring signals included in the OAM frame is an alarm signal (that is, when at least one of RMT-EQP, RMT-POWER, RMT-TX-LINK, and RMT-FX-LINK indicates an abnormality) the), port unit 2a _i executes selection processing of the alarm signal based on a predetermined priority order, and notifies the alarm signal selected by the selecting process to the OpS.

Further, the alarm signal DOWNLINK detected by the port unit 1a _i of the physical layer device 11, the alarm signal UPLINK detected by the port unit 1b _i , and the alarm signal EQP detected by the CPU 14 are also given to the port unit 2a _i . Port unit 2a _i, for even these alarm signals, performs selection processing according to a predetermined priority order, giving a warning signal selected by the selecting process to the OpS.

  FIG. 7 shows an example of predetermined priorities according to the present embodiment in a table format (priority table). In this figure, the numbers “1”, “2”, and “3” are assigned in order from the highest priority.

  When the maintenance sublayer device 12 receives two or more alarm signals having different priorities at the same time or within a predetermined time ("predetermined time" will be described later), the maintenance sublayer device 12 selects and selects the alarm signal having the higher priority. The alarm signal is notified to the OpS via the interface device.

  This priority level defines that a failure corresponding to a high priority alarm signal has occurred when two or more alarm signals are received simultaneously or within a predetermined time.

  For example, when the maintenance sublayer device 12 receives an alarm signal EQP due to a device failure of the in-station MC2 and an alarm signal DOWNLINK due to a link failure of the in-station MC1, at the same time or within a predetermined time, these two alarm signals are generated. As the cause is due to a device failure corresponding to the alarm signal EQP having a high priority, the alarm signal EQP having the high priority is selected and the alarm signal EQP is notified to the OpS.

  Similarly, when three alarm signals RMT-POWER, DOWNLINK, and RMT-FX-LINK are received, RMT-POWER is selected. The former is selected when the alarm signals RMT-POWER and DOWNLINK are received, and the former is selected when the alarm signals RMT-POWER and RMT-EQP are received.

  Further, the relationship between the priority levels 2 and 3 and the relationship between the priority levels 1 and 3 are the same. When the alarm signals DOWNLINK and RMT-FX-LINK are received, the former is selected. . When the alarm signals RMT-POWER and RMT-FX-LINK are received, the former is selected.

  Here, the priority order defines the relationship only between alarm signals in the same row (horizontal column) and does not define the relationship between alarm signals located in different rows. Therefore, for example, when the alarm signals RMT-TX-LINK and RMT-FX-LINK are received simultaneously or within a predetermined time, the maintenance sublayer device 12 selects both alarm signals without selecting one of the alarm signals. An alarm signal is notified to OpS. The same applies to alarm signals located in other different rows.

  In this way, the priority order is defined, and when a plurality of warning signals having a priority relation are received at the same time or within a predetermined time, an alarm signal having a higher priority order is selected and given to OpS. The operator (or the supervisor) can specify one cause of the failure. In addition, useless alarm signal notification from the maintenance sublayer device 12 to the OpS can be prevented, and communication costs can be reduced.

  Here, the time for receiving the alarm signal is set to “within a predetermined time” in addition to “simultaneous” for the following reason. That is, the alarm signals (RMT-POWR, RMT-TX-LINK, RMT-FX-LINK, and RMT-EQP) from the home MC 2 are received by the in-station MC 1 by the same OAM frame and can be processed simultaneously. On the other hand, an alarm signal (EQP, DOWNLINK, etc.) detected and notified by the physical layer device 11 of the in-house MC 1 is generally notified with a time difference from the alarm signal received by the OAM frame from the home MC 2. For this reason, if priority processing is not performed for a plurality of alarm signals received after waiting for a certain time, the maintenance sublayer device 11 notifies the OpS of a plurality of alarm signals including unnecessary alarm signals, as in the prior art. Become. For this reason, it is within a predetermined time.

  This predetermined time is set to, for example, about twice or three times the period (polling period) T at which the maintenance sublayer device 12 polls the alarm signal. That is, when receiving one of the alarm signals shown in the table of FIG. 7, the maintenance sublayer apparatus 12 waits for reception of another alarm signal for a time 2T or 3T after the reception. Then, the maintenance sublayer device 12 performs priority processing when another alarm signal is received, notifies the high priority alarm signal of OpS, and does not perform priority processing when it is not received, and receives it first. The alarm signal is notified to OpS.

  FIG. 8 is a time chart showing an example of priority processing of alarm signals. When the alarm signal RMT-FX-LINK is received at the alarm monitoring time (ie polling time) (B), the maintenance sublayer device 12 waits about two cycles and detects the alarm signal DOWNLINK at the polling time (D). In such a case, DOWNLINK is selected and notified to OpS. On the other hand, when the maintenance sublayer apparatus 12 does not receive the alarm signal DOWNLINK, the maintenance sublayer apparatus 12 notifies the OpS of the alarm signal RMT-FX-LINK.

  Contrary to the event shown in FIG. 8, the alarm signal DOWNLINK is not received before RMT-FX-LINK. This is because the intra-station MC1 cannot receive the OAM frame due to the link disconnection. Therefore, the maintenance sublayer device 12 can omit the priority processing after waiting for the elapse of the predetermined time for the order of alarm signals that cannot occur.

  Such priority processing is performed independently for each port section of the maintenance sublayer apparatus 12.

  In the embodiment described so far, the alarm signal is notified to the OpS, but the alarm signal may be displayed on a display device (CRT display, liquid crystal display, etc.) included in the in-office MC2.

<Folding test>
Next, the folding test according to this embodiment will be described. The loopback test according to the present embodiment is performed including the logical layer device 13 of the intra-station MC1. As a result, the logical layer can be tested, and whether the logical layer is normal or abnormal can be checked.

  In order to perform the loopback test including the logical layer device 13, in this embodiment, the test frame is transmitted so as to pass through not only the maintenance sublayer device 12 and the physical layer device 11 but also the logical layer device 13. .

Specifically, the test frame created by the test frame processing unit 2b of the maintenance sublayer device 12 of the in-station MC1 is transmitted to the logical layer device 13, and the specified port unit 2a of the maintenance sublayer device 12 is transmitted from the logical layer device 13. sent to _i . The test frame is supplied from the port unit 2a _i to the port portion 1a _i of the physical layer device 11, from the port portion 1a _i through the optical fiber is transmitted to the home MC2 # i. Thereafter, the test frames folded back from home MC2 # i is input to the logical layer device 13 from the port portion 1a _i via the port unit 2a _i, returns from the logical layer device 13 to the test frame processing unit 2b.

  Note that since there may be no logical layer in the home MC 2, the test frame passes through the physical layer device and the maintenance sublayer device (see FIG. 2) in the home MC 2. When a logical layer device exists in the home MC 2, the test frame may pass through this logical layer.

  In order to allow the test frame to pass through the logical layer, the test frame is not a special frame as in the prior art, but a MAC frame. FIG. 9 shows a format of a test frame according to this embodiment.

  The test frame consists of a destination address (destination MAC address) DA (6 bytes), a source address (source MAC address) SA (6 bytes), an ether type (frame type) (2 bytes), and user data (48 to 1498 bytes). ), CRC (2 bytes), and frame check sequence FCS (4 bytes). User data and CRC constitute a payload part. This test frame is generated by the test frame processing unit 2b.

  The destination MAC address (hereinafter abbreviated as “destination address”) DA does not need to be specified because this test frame is communicated only between the in-station MC 1 and the in-house MC 2 and is not transmitted to the PC 3 or WAN 4 or the like. However, in this embodiment, the port address (port number) of the logical layer device 13 that is the transmission destination is set. This makes debugging easier.

  The source MAC address (hereinafter abbreviated as “source address”) SA does not need to be specified, but in order to facilitate debugging, port #L is a port to which the test frame processing unit 2b is connected. Port number.

The ether type (frame type) is set to a fixed value of 0x9000 indicating loopback in the test frame. A random value for testing is set in the user data. The CRC stores the value of the result calculated by the calculation formula x ¹⁶ + x ¹⁵ + x ² +1 for the user data values from the beginning of the payload part to immediately before the CRC. The FCS stores an FCS calculation result compliant with IEEE802.3.

  Here, the reason why the payload is composed of random data (user data) and CRC for the test frame normality check is as follows. That is, a general-purpose logical layer device (for example, a MAC chip) performs FCS inspection on a received frame and discards the frame when an error is detected. However, when a frame is transmitted to the outside, an FCS calculation is often performed and a new calculation result is overwritten in the FCS area. If a bit error occurs in the logical layer part, the error detection becomes impossible because the FCS calculation and overwriting are performed with the data having the error. For the above reasons, it is possible to detect an error occurring in the logical layer apparatus by performing a CRC check on the payload.

  At the time of transmission to the optical fiber 7, an 8-byte preamble is added to the head of the frame.

  The loopback test using the test frame includes a first method using a switching function based on logical layer MAC address learning and a second method using a virtual LAN (VLAN: Virtual Local Area Network) function. . Details of each will be described below.

(1) First Method In the first method, the logical layer device 13 identifies the destination address DA and the source address SA of the test frame, and uses the address learning function and the switching function of the logical layer device 13 to perform the test. The port #i to which the target in-home MC2 is connected is selected and the test frame is transferred.

FIG. 10 is a sequence diagram showing the flow of the loopback test process according to the first method. Here, as an example, port #L (port unit 3a _L ) of the logical layer apparatus 13 to which the test frame processing unit 2b is connected is set as port # 8, N = 8, and port # N-1 is set as port 7. . A case where the test is performed for port # 0 will be described.

  In FIG. 10, a loopback test start request (LOOP-MCQ) and start response (LOOP-MCS) using an OAM frame are transmitted / received as in the prior art, and a loop point is set in the physical layer for in-house MC2, and in-station Also for MC1, the processing after setting a loop route in the physical layer is shown.

  The test frame processing unit 2b sets the destination MAC address DA as the port number of the port # 0 of the logical layer device 13 (0x00-00-00-00-00-01) and sets the source MAC address SA as # 8. A test frame having a port number (0x00-00-00-00-00-09) is generated (step S1). Both addresses are unicast addresses.

Subsequently, the test frame processing unit 2 b transmits the generated test frame to the logical layer device 13. The port unit 3a _L (port # 8) of the logical layer device 13 learns the source address SA0x00-00-00-00-00-09 by receiving the test frame, and the address held by the logical layer device 13 0x00-00-00-00-00-09 is written in the learning memory (not shown) as the address (local address) of port # 8 (step S2).

  The logical layer device 13 refers to the test frame destination address DA and outputs the test frame from the port # 0 indicated by this address. The addresses 0x00-00-00-00-00-01 to 0x00-00-00-00-00-08 corresponding to the ports # 0 to # 7 of the logical layer device 13 are the addresses held by the logical layer device 13 The learning memory is preset by the CPU 14 at the time of initial setting or the like. Then, the logical layer device 13 transfers the test frame to a port having an address that matches the destination address DA and outputs it.

The test frame output from the port # 0 of the logical layer device 13 is received by the port # 0 (port unit 2a ₀ ) of the maintenance sublayer device 12, and is received from the port # 0 (port unit 1a ₀ ) of the physical layer device 11 MC2 is sent to the _1.

Kaee been tested frame folded from home MC2 ₁ is received by the port 2a ₀ Maintenance sublayer device 12 via the port portion 1a ₀ of the physical layer device 11. Port unit 2a ₀ Maintenance sublayer, the received test frame (MAC frame) is determined to be the test frame from the Ethertype (step S3), and replace the source address SA and destination address DA (i.e., DA = 0x00-00-00-00-09, SA = 0x00-00-00-00-00-01) (step S4). Then, the port part 2a ₀ of the maintenance sublayer recalculates the FCS based on the address exchange (step S5) and transmits it to the port part 3a ₀ of the logical layer device 13.

The port unit 3a ₀ of the logical layer device 13 searches the address learning table for a port that matches the destination address DA of the received test frame. Since the address learning table stores that the destination address DA0x00-00-00-00-09 is the address of the destination port # 8 by the address learning function, the test frame is transmitted to the port # 8, and the port # 8 8 to the test frame processing unit 2b.

  If a data error occurs after the FSC recalculation in step S5, an FCS error is detected upon reception by the logical layer device 13, and this test frame is discarded.

  The test frame processing unit 2b performs a CRC check on the received test frame. If an error is detected as a result of the CRC check, the test frame processing unit 2b counts to an error counter held by itself.

  The loopback test using this test frame is repeated a plurality of times (for example, 256 times) for one port, and during this time, error counters are accumulated by CRC inspection. The test frame processing unit 2b also counts the number of returned test frames. The difference between the number of transmitted test frames and the number of returned test frames means the number of frames discarded due to an FCS error.

  After completion of the test, as a result of the loopback test, the test frame processing unit 2b notifies the OpS of the number of received frames and the number of frames in which a CRC error is detected among the received frames.

  This first method is particularly effective when the general-purpose device used in the home MC 2 does not guarantee the transparency of the IEEE 802.1Q tag and cannot use the VLAN function of the second method.

  In the first method, the test frame turning point (loop point) can be set in the physical layer device 11 of the in-station MC 1 without using the home MC 2. This makes it possible to isolate (narrow down) the fault location.

  In addition, by setting the test time to be variable, it is possible to perform from short-term continuity confirmation tests to long-term transmission characteristics observations. Furthermore, by setting the test frame length to be variable, it is possible to inspect the difference in conduction characteristics depending on the data length.

  It is also possible to test whether or not the test frame processing unit 2b can detect a CRC error by setting the CRC value for user data (random data) to an erroneous value and transmitting / replying it. That is, it is possible to test the error detection function of the test frame processing unit 2b.

  In addition, the failure layer can be narrowed down (specified) by using it together with the loopback test for testing the conventional physical layer.

(2) Second method The second method uses the test frame destination address DA as the broadcast address, and in combination with the IEEE802.1QTag function, selects the port to which the in-home MC2 to be tested is connected, and transfers the test frame. Is to do.

  When a device that guarantees the transmission of IEEE802.1QTag is used in home MC2, it is effective to use the second method.

  FIG. 11 shows the format of a test frame in the second method. The difference from the test frame shown in FIG. 9 described above is that IEEE802.1QTag (4 bytes) is included between the source address SA and the ether type.

  The destination address DA is a broadcast address 0xFF-FF-FF-FF-FF-FF. The source address SA is the port number 0x00-00-00-00-00-09 of the port # 8 (#L) connected to the test frame processing unit 2b as in the first method.

  IEEE802.1Qtag consists of a 2-byte TPID (Tag Protocol Identifier) and a 2-byte TCI (Tag Control Identifier). The TCI further includes a 3-bit user priority used for QoS and the like, a 1-bit CFI (Canonical Format Indicator) used for processing such as token ring, and a 12-bit VLAN-ID (VLAN Identifier). In VLAN, TPID and VLAN-ID are required for processing of the logical layer device 13.

  The TPID is set to 0x8100 indicating that the VLAN is used by the test frame processing unit 2b.

  The VLAN-ID is an identifier for identifying each VLAN when a plurality of VLANs are set on the network. In the logical layer device 13, eight VLANs (port type VLAN, port base VLAN) connecting each of the ports # 0 to # 7 and the port # 8 are set in advance by the CPU 14 at the time of initial setting or the like. Each VLAN is pre-assigned by the CPU 14 with a VLAN-ID (ID not used by the user). These VLAN-IDs are also notified (set) in advance by the CPU 14 to the test frame processing unit 2b.

  The payload has random data and CRC as in FIG. 9, and the reason for this configuration is the same as that described in the first method.

  FIG. 12 is a sequence diagram showing the flow of the loopback test process according to the second method.

  For example, when the test frame processing unit 2b receives a command from OpS to perform the test for port # 0, the test frame processing unit 2b generates a test frame in which the VLAN-ID corresponding to the port # 0 is set (step S11), and the logical layer device 13 To port # 8.

  The port # 8 recognizes that this test frame is a VLAN frame because the TPID of the received test frame is 0x8100. Based on the VLAN-ID, the test frame is transferred to the port # 8 of the logical layer device 13. Transfer to 0. Although the destination address DA is a broadcast address, the destination port belonging to the test VLAN is port # 0, so the test frame is transferred only to port # 0. Moreover, the port learning address of the port # 8 is stored in the address learning memory as the address 0x00-00-00-00-00-09 by the address learning function of the logical layer device 13.

  In the home MC 2, when VLAN is allowed, the port # 0 of the logical layer device 13 transmits the test frame as it is to the port # 0 of the maintenance sublayer device 12. This test frame is transmitted to the home MC 2 # 0, returned, and returned to the port # 0 of the logical layer device 13.

  On the other hand, there is a case where VLAN is not allowed in the home MC 2. In this case, the port # 0 of the logical layer device 13 removes the IEEE802.1Qtag from the test frame (step S12), and the removed test frame (the same format as the test frame shown in FIG. 9) is the maintenance sublayer device 12. Can also be sent to port # 0. Thereafter, when the test frame returned from the in-home device 2 # 0 is received by the port # 0 of the logical layer device 13, the port # 0 of the logical layer device 13 adds the deleted IEEE802.1Qtag to the test frame. (Step S13).

  The test frame returned from the home MC # 0 passes through the maintenance sublayer device 12 and is received by the port # 0 of the logical layer device 13. That is, the maintenance sublayer device 13 does not execute the exchange of the destination address DA and the source address SA and the FCS recalculation process in the first method. As a result, high-speed communication of test frames becomes possible, the configuration of the maintenance sublayer device 12 can be simplified, and the circuit scale can be reduced.

  The port # 0 of the logical layer device 13 transfers the received test frame to the port # 8 according to the VLAN setting. Further, the port learning address of the port # 0 is stored in the address learning memory as the address 0x00-00-00-00-00-09 by the address learning function of the logical layer device 13. Port # 8 transmits a test frame to the test frame processing unit 2b.

  If an error occurs in the test frame before it is received by port # 0 of the logical layer device 13, the test frame is discarded due to FCS error detection at the time of reception by the logical layer device 13, and is sent to the test frame processing unit 2b. Will not be sent.

  Similarly to the first method, the test frame processing unit 2b performs a CRC check on the received test frame, and notifies the OpS of the number of frames in which a CRC error has been detected and the number of received frames as a test result.

  This second method also enables a test including a logic layer, and can perform a test at a higher speed.

  Note that, when test frames are received at ports # 0 and # 8 of the logical layer device 13, these port addresses are repeatedly learned as addresses 0x00-00-00-00-00-09. . If this learning is repeated at high speed, depending on the MAC chip used, it may be determined that movement has occurred in the terminal (home MC2) and the test frame may be discarded. In order to prevent this, it is preferable to set the test frame transmission rate low so that the test frame is not discarded.

  In the second method, similarly to the first method, the turning point of the test frame can be set in the physical layer device 11 of the in-station MC 1 in addition to the home MC 2. This makes it possible to isolate the fault location. Also, by making the test time variable, it is possible to check from short-time conduction to observation of long-term transmission characteristics.

  Furthermore, by making the test frame length variable, it is possible to inspect the difference in conduction characteristics depending on the data length. It is also possible to check the error detection function of the test frame processing unit 2b by setting the CRC calculation result to an erroneous value. By using it together with a loopback test that can confirm the function of the conventional physical layer only, the failure layer can also be identified.

  In the embodiment described so far, the result of the loopback test is notified to the OpS, but the test result may be displayed on the display device of the in-office MC1.

(Supplementary note 1) In the subscriber line terminal equipment connected to the subscriber line termination equipment by optical fiber,
A receiver for receiving a plurality of monitoring signals transmitted from the subscriber line termination device via the optical fiber and respectively representing normality or abnormality of a plurality of monitoring items in the subscriber termination device;
If two or more of the plurality of monitoring signals received by the receiving unit indicate an abnormality, the monitoring signal indicating the two or more abnormalities has a high priority based on a predetermined priority order. A selection unit for selecting a monitoring signal;
A subscriber line terminal station device comprising:

(Appendix 2) In Appendix 1,
The plurality of monitoring signals include a first signal indicating normality or abnormality of a power source of the subscriber line termination device, a second signal indicating normality or abnormality of a cable connecting the subscriber line termination device and a user terminal, A third signal representing normality or abnormality of the optical signal reception state of the optical fiber of the subscriber termination device, and a fourth signal representing normality or abnormality of the device of the subscriber line termination device,
The priority order defines the priority order of the first signal and the second signal, the priority order of the first signal and the third signal, and the priority order of the first signal and the fourth signal. ,
A subscriber line terminal station device.

(Appendix 3) In Appendix 1 or 2,
The plurality of monitoring signals are transmitted from the subscriber line termination device by an OAM frame and received by the receiving unit.
A subscriber line terminal station device.

(Supplementary note 4) In the subscriber line terminal equipment connected to the subscriber line terminal equipment by optical fiber,
A monitoring unit for monitoring normality or abnormality of a plurality of monitoring items in the own device and outputting an alarm signal corresponding to the monitoring item in which the abnormality is detected;
When the monitoring unit outputs two or more alarm signals respectively corresponding to two or more monitoring items of the plurality of monitoring items, a priority order based on a predetermined priority order from the two or more alarm signals A selection section for selecting a high alarm signal,
A subscriber line terminal station device comprising:

(Appendix 5) In Appendix 4,
The alarm signal includes a signal representing a device failure of the own device and a signal representing an abnormality of the optical fiber,
The priority order defines the priority order of these two signals.
A subscriber line terminal station device.

(Supplementary note 6) In a subscriber line terminal station apparatus connected to a subscriber line termination apparatus by an optical fiber,
A monitoring unit that monitors normality or abnormality of a plurality of monitoring items in its own device, and outputs an alarm signal corresponding to the monitoring item that detected the abnormality;
A receiver for receiving a plurality of monitoring signals transmitted from the subscriber line termination device via the optical fiber and respectively representing normality or abnormality of a plurality of monitoring items in the subscriber termination device;
When the monitoring unit outputs two or more alarm signals respectively corresponding to two or more monitoring items of the plurality of monitoring items, a priority order based on a predetermined priority order from the two or more alarm signals When two or more of the plurality of monitoring signals received by the receiving unit indicate an abnormality, the priority order is selected from the monitoring signals indicating the two or more abnormalities. The monitoring signal having a high priority is selected based on the above, or the monitoring unit outputs an alarm signal corresponding to at least one monitoring item among the plurality of monitoring items and is received by the receiving unit When at least one of the plurality of monitoring signals indicates an abnormality, the warning signal having a higher priority order based on the priority order among the at least one warning signal and the at least one monitoring signal. Others a selection unit for selecting a monitoring signal,
A subscriber line terminal station device comprising:

(Appendix 7) In Appendix 6,
The plurality of monitoring signals include a first signal indicating normality or abnormality of a power source of the subscriber line termination device, a second signal indicating normality or abnormality of a cable connecting the subscriber line termination device and a user terminal, A third signal representing normality or abnormality of the optical signal reception state of the optical fiber of the subscriber termination device, and a fourth signal representing normality or abnormality of the device of the subscriber line termination device,
The alarm signal includes a fifth signal representing a device failure of the subscriber line terminal device and a sixth signal representing an abnormality of the optical fiber,
The priority order includes the priority order of the first signal and the second signal, the priority order of the first signal and the third signal, the priority order of the first signal and the fourth signal, Prescribing the priority between the signal and the sixth signal, the priority between the sixth signal and the third signal, and the priority between the fifth signal and the sixth signal;
A subscriber line terminal station device.

(Appendix 8) In Appendix 6 or 7,
The selection unit is configured to output the two or more alarm signals at the same time or within a predetermined time, when two or more monitoring signals indicating the abnormality are received by the reception unit, or When the monitoring unit outputs the at least one warning signal and at least one monitoring signal indicating the abnormality is received by the receiving unit, the selection based on the priority order is performed.
A subscriber line terminal station device.

(Supplementary Note 9) In any one of Supplementary Notes 6 to 8,
The plurality of monitoring signals are transmitted from the subscriber line termination device by an OAM frame and received by the receiving unit.
A subscriber line terminal station device.

(Supplementary Note 10) A physical layer device that performs physical layer processing on data that is connected to a subscriber line termination device via an optical fiber and communicates via the optical fiber, and a logical layer that performs logical layer processing In a subscriber line terminal station apparatus having a device and a maintenance sublayer device connected to the physical layer device and the logical layer device, which executes processing of a maintenance sublayer constituting a part of the physical layer,
The maintenance sublayer device
A test frame including a payload portion having test data for performing a loopback test with the subscriber line termination device or the physical layer device is generated and transmitted to the logical layer device, and the subscriber line termination A test frame processing unit that receives and inspects the test frame returned from the device or the physical layer device from the logical layer device;
A port unit that transfers the test frame received from the logical layer device to the physical layer device, and transfers the test frame received from the physical layer device to the logical layer device;
With
The logical layer device includes a transfer unit that transfers the test frame from the test frame processing unit to the port unit and transfers the test frame from the port unit to the test frame processing unit;
A subscriber line terminal device characterized by the above.

(Appendix 11) In Appendix 10,
The test frame includes, as a destination address, an identifier of a first port connected to the port unit in the transfer unit, and an identifier of a second port connected to the test frame processing unit in the transfer unit as a source address. Including
The port unit exchanges the source address and the destination address of the test frame received from the physical layer device;
The transfer unit stores the identifier of the first port in advance, and when receiving a test frame from the test frame processing unit, stores the transmission source address of the received test frame as the identifier of the second port, When the test frame is transferred from the first port to the port unit based on the destination address and the test frame is received from the port unit, the test frame is transmitted from the second port based on the destination address of the received test frame. Forward to the test frame processor,
A subscriber line terminal station device.

(Appendix 12) In Appendix 11,
The test frame further includes a frame check sequence;
The port unit recalculates the frame check sequence of the test frame after exchanging the source address and the destination address of the test frame received from the physical layer, and writes the frame check sequence to the test frame.
A subscriber line terminal station device.

(Supplementary note 13) In Supplementary note 10,
The test frame further includes a virtual LAN tag having a virtual LAN identifier,
The logical layer device corresponds to an identifier of the virtual LAN that connects a first port connected to the port unit in the transfer unit and a second port connected to the test frame processing unit in the transfer unit. A virtual LAN is preconfigured,
The transfer unit transfers the test frame from the test frame processing unit via the second port and the first port based on the virtual LAN corresponding to the virtual LAN identifier of the virtual LAN tag included in the test frame. Transfer to the port unit, and transfer from the port unit to the test frame processing unit via the first port and the second port,
A subscriber line terminal station device.

(Supplementary Note 14) In any one of Supplementary Notes 10 to 13,
The payload part consists of test data and error check data of the test data,
The test frame processing unit inspects the test frame returned based on the error check data;
A subscriber line terminal station device.

(Appendix 15) In Appendix 14,
The subscriber line terminal station device, wherein the test frame processing unit sets the test data to an incorrect value and transmits the test data.

(Supplementary Note 16) In any one of Supplementary Notes 10 to 15,
The subscriber line terminal station apparatus, wherein the payload portion has a variable length.

(Supplementary Note 17) In any one of Supplementary Notes 10 to 16,
The subscriber line terminal station device, wherein the test frame is transmitted and received a plurality of times, and the number of transmission and reception is settable.

(Supplementary note 18) In any one of Supplementary notes 10 to 17,
The physical layer device returns inside the device and returns it to the first port unit.
A subscriber line terminal station device.

(Supplementary note 19) In any one of Supplementary notes 10 to 18,
The logical layer is a medium access control layer, and the test frame is a medium access control frame;
A subscriber line terminal station device.

(Supplementary note 20) A physical layer device connected to a subscriber line termination device via an optical fiber and performing physical layer processing on data communicated via the optical fiber, and a logical layer performing logical layer processing A loopback test of a subscriber line terminal station apparatus having a device and a maintenance sublayer device connected to the physical layer device and the logical layer device, which executes processing of a maintenance sublayer constituting a part of the physical layer A method,
The maintenance sublayer device generates a test frame including a payload portion having test data for performing a loopback test with the subscriber line termination device or the physical layer device, and transmits the test frame to the logical layer device.
The logical layer device transfers the test frame from the maintenance sublayer device to the physical layer device via the maintenance sublayer device;
The maintenance sublayer device returns the test frame returned from the subscriber line termination device or the physical layer device to the logical layer device,
The logical layer device further returns the test frame returned from the maintenance sublayer device to the maintenance sublayer device,
The maintenance sublayer device receives and inspects the test frame returned from the logical layer device;
Return test method.

(A) and (B) are blocks showing the overall configuration of a subscriber optical communication system having a subscriber line terminal station device and a subscriber termination device. It is a block diagram which shows the logic hierarchy model of in-office MC and in-home MC. (A) shows the state of transmission and reception of control signals and monitoring signals, (B) shows the contents of the control signals, (C) shows the contents of the monitoring signals, and (D) shows an alarm detected by the in-station MC. . It is a block diagram which shows the detailed structure of in-station MC by embodiment of this invention. (A) shows the frame format of the OAM frame, and (B) shows the contents of each bit data constituting the OAM frame. A mode that an OAM frame is inserted and transmitted in an idle field (IPG) is shown. The priority order of a plurality of alarm signals is shown in a table format. It is a time chart which shows an example of the priority process of an alarm signal. 2 shows a format of a test frame according to an embodiment of the present invention. It is a sequence diagram which shows the flow of the process of the return | turnback test by a 1st method. 2 shows a format of a test frame according to an embodiment of the present invention. It is a sequence diagram which shows the flow of the process of the return | turnback test by a 2nd method. It is a sequence diagram of a conventional loopback test. The format of the conventional test frame is shown.

Explanation of symbols

1 Subscriber line terminal equipment (in-house MC)
2 _{0 to} 2 _n subscriber line terminating equipment (in-house MC)
5 ₀ to 5 _n UTP cable 6 ₀ to 6 _n optical fiber cable 7 ₀ to _7-n UTP cable 14 CPU
15 memory 11 physical layer device 12 maintenance sublayer device 13 logical layer device 1a ₀ ~1a _N-1 physical layer device for ports 2a ₀ ~2a _N-1 ports 2b test frame processing unit 3a of the maintenance sublayer device ₀ to 3 A _{N -1} Port part of logical layer device

Claims (2)

A physical layer device that performs physical layer processing on data that is connected to a subscriber line termination device via an optical fiber and communicates via the optical fiber; a logical layer device that performs logical layer processing; In a subscriber line terminal apparatus that performs processing of a maintenance sublayer that forms part of a physical layer and has a maintenance sublayer apparatus connected to the physical layer apparatus and the logical layer apparatus,
The maintenance sublayer device
A test frame including a payload portion having test data for performing a loopback test with the subscriber line termination device or the physical layer device is generated and transmitted to the logical layer device, and the subscriber line termination A test frame processing unit that receives and inspects the test frame returned from the device or the physical layer device from the logical layer device;
A first port unit that transfers the test frame received from the logical layer device to the physical layer device, and transfers the test frame received from the physical layer device to the logical layer device;
With
The logical layer device includes a second port unit that transfers the test frame from the test frame processing unit to the first port unit, and transfers the test frame from the first port unit to the test frame processing unit. Equipped,
A subscriber line terminal device characterized by the above. A physical layer device connected to a subscriber line termination device via an optical fiber and performing physical layer processing on data communicated via the optical fiber; a logical layer device performing logical layer processing; A loopback test method for a subscriber line terminal apparatus that performs processing of a maintenance sublayer that forms part of a physical layer and includes a maintenance sublayer apparatus connected to the physical layer apparatus and the logical layer apparatus. ,
The maintenance sublayer device generates a test frame including a payload portion having test data for performing a loopback test with the subscriber line termination device or the physical layer device, and transmits the test frame to the logical layer device.
The logical layer device transfers the test frame from the maintenance sublayer device to the physical layer device via the maintenance sublayer device;
The maintenance sublayer device returns the test frame returned from the subscriber line termination device or the physical layer device to the logical layer device,
The logical layer device further returns the test frame returned from the maintenance sublayer device to the maintenance sublayer device,
The maintenance sublayer device receives and inspects the test frame returned from the logical layer device;
Return test method.

Images