JP2018129758A - Subscriber line terminal apparatus, transport device, and misconnection detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect misconnection in passive optical network system.SOLUTION: A passive optical network function part of a subscriber line terminal apparatus in a passive optical network system including a terminal assigned with a medium access control address, a subscriber line terminator, and a subscriber line terminal apparatus allocates a logical link identifier to the subscriber line terminal apparatus, upon receiving a registration request from the subscriber line terminal apparatus, deletes the logical link identifier of an uplink frame upon receiving the uplink frame in which the logical link identifier from the subscriber line terminal apparatus is written, and transfers a transfer uplink frame in which an internal virtual area local area network identifier corresponding to the logical link identifier of the uplink frame, based on a logical link identifier-internal virtual area local area network identifier table. A history information storage section stores personal history of a combination of the medium access control address in a transfer uplink frame, and a corresponding internal virtual area local area network identifier.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a subscriber line terminal station device, a transfer device, and an erroneous connection detection method.

  Due to increasing needs for high-speed access services, FTTH (Fiber To The Home) is spreading worldwide. Most of the FTTH service accommodates a plurality of subscriber line terminal units (ONU: Optical Network Unit) by time division multiplexing (TDM) by subscriber line terminal equipment (OLT). It is provided by an economical passive optical network (PON) system. In uplink communication of TDM-PON, the system band is shared between ONUs by bandwidth allocation in the OLT, and each ONU transmits signal light intermittently only within the transmission permission time notified from the OLT. The collision of signal lights is prevented. The current main systems are GE-PON (Gigabit Ethernet PON) and G-PON (Gigabit-Capable PON), whose transmission speed is gigabit, but upload / download large files in addition to the progress of video distribution services. With the advent of applications and the like, there is a demand for further increase in capacity of the PON system.

NTT Technical Journal October 2005 "Technology Basic Course GE-PON Technology 3rd DBA Function" IEEE Standard for Ethernet 802.3-2012 SECTION FIVE “64. Multipoint MAC Control”

  In IP telephones, video conference systems, and the like, it is necessary to avoid unintentional connection (misconnection) with the other party from the viewpoint of erroneous charging and personal information protection. In the PON system, in order to identify a user, a logical link identifier (LLID: Logical Link Identifier (specified in Non-Patent Document 2)) is assigned to the ONU on the user side from the OLT, and the higher network side than the OLT. Thus, a virtual local area network identifier (VID) is used. The OLT converts the LLID and the VID to each other. However, if a frame with an unintended LLID or VID is transmitted due to a failure of the OLT, an erroneous connection may occur. In the conventional PON system, since such an erroneous connection could not be detected, there was a possibility that an appropriate user response could not be performed when an erroneous connection occurred.

  In view of the above circumstances, an object of the present invention is to provide an OLT and a transfer device that detect an erroneous connection in a PON system.

  One aspect of the present invention is a terminal device to which a medium access control address is assigned, a subscriber line terminal device connected to the terminal device, and a subscriber line terminal station connected to a higher level of the subscriber line terminal device. A subscriber line terminal device in a passive optical network system comprising a device, wherein when a registration request is received from the subscriber line termination device, a logical link identifier is allocated to the subscriber line termination device, and the subscriber line termination When the uplink frame in which the logical link identifier is written is received from the device, the logical link identifier of the uplink frame is deleted, and the uplink frame based on the logical link identifier-internal virtual local area network identifier conversion table to be held is deleted. Transfer upstream frame in which an internal virtual local area network identifier corresponding to the logical link identifier is written A passive optical network function unit for transferring a history information, and a history information storage unit for storing a history of combinations of the medium access control address in the transferred uplink frame and the corresponding internal virtual local area network identifier, Prepare.

  One aspect of the present invention is the above-described subscriber line terminal station apparatus, comprising: an internal virtual local area network identifier-virtual local area network identifier conversion table relating to a correspondence between an internal virtual local area network identifier and a virtual local area network identifier. Based on the retained internal virtual local area network identifier-virtual local area network identifier conversion unit, the internal virtual local area network identifier-virtual local area network identifier conversion table, and the history, the medium access control address and the internal virtual local area network identifier A history conversion unit that outputs a combination with a virtual local area network identifier corresponding to the operation, and an operation that outputs information of the history conversion unit to an external operation system Further comprising an emission system output unit.

  One aspect of the present invention is the above-described subscriber line terminal device, wherein the erroneous connection detection unit detects different virtual local area network identifiers at the same medium access control address in the history stored in the history information storage unit. Is further provided.

  According to an aspect of the present invention, when a terminal device to which a medium access control address is assigned, a subscriber line termination device connected to the terminal device, and a registration request from the subscriber line termination device are received, the subscriber A logical link identifier that allocates a logical link identifier to a line termination device and deletes and retains the logical link identifier of the uplink frame when receiving an uplink frame in which the logical link identifier is written from the subscriber line termination device A transfer connected to a higher level of a subscriber line termination device that transfers a higher level transfer upstream frame in which a virtual local area network identifier corresponding to the logical link identifier of the upstream frame is written based on a virtual local area network identifier conversion table. A receiver terminal device and a transfer device connected to a higher level of the subscriber line terminal device. A transfer apparatus in an optical network system, comprising a media access control address in the transfer upstream frame, the history information storage section for storing a history of a combination of a virtual local area network identifier the corresponding.

  One aspect of the present invention is the transfer apparatus described above, further including an erroneous connection detection unit that detects different virtual local area network identifiers with the same medium access control address in the history stored in the history information storage unit.

  One aspect of the present invention is a terminal device to which a medium access control address is assigned, a subscriber line terminal device connected to the terminal device, and a subscriber line terminal station connected to a higher level of the subscriber line terminal device. An erroneous connection detection method executed by a subscriber line terminal device in a passive optical network system comprising a device, wherein when a registration request is received from the subscriber line terminal device, a logical link identifier is assigned to the subscriber line terminal device. A logical link identifier that deletes and retains the logical link identifier of the uplink frame and retains the logical link identifier when receiving the uplink frame in which the logical link identifier is written from the subscriber line terminating device. An internal virtual local area network corresponding to the logical link identifier of the upstream frame based on a conversion table A step of transferring a transfer uplink frame in which an identifier is written; and a step of accumulating a history of a combination of a medium access control address in the transferred transfer uplink frame and the corresponding internal virtual local area network identifier. Have.

  According to the present invention, it is possible to quickly detect the occurrence of an erroneous connection and to promptly perform an appropriate user response.

1 is a diagram illustrating an overall configuration of a PON system 10. FIG. It is a block diagram showing the structure of OLT100 of 1st Embodiment. It is a flowchart showing operation | movement of OLT100 of 1st Embodiment. It is a block diagram showing the structure of OLT200 of 2nd Embodiment. It is a flowchart showing operation | movement of OLT200 of 2nd Embodiment. It is a flowchart showing the operation | movement in which OPS acquires historical information from OLT. It is a block diagram showing the structure of OLT300 of 3rd Embodiment. It is a flowchart showing operation | movement of OLT300 of 3rd Embodiment.

  FIG. 1 shows the overall configuration of the PON system 10. The PON system 10 includes an OLT 100 and a plurality of ONUs 1, 2,..., N,..., N connected to the OLT 100 via an optical fiber transmission line 12. In order to make a one-to-many connection between the OLT 100 and the ONU, the optical fiber transmission line 12 is branched using an optical multiplexing / demultiplexing means 11, for example, an optical splitter. The ONU is connected to a terminal device such as a personal computer or a router. The OLT 100 relays communication between a terminal device and an upper network device such as a server or a communication device that provides a service in response to a request from the terminal device. The OLT 100 assigns a different LLID to each ONU in response to a registration request from the ONU. In FIG. 1, the LLIDs assigned to the ONUs 1, 2, n, and N are aaa, bbb, ccc, and ddd, respectively.

  In the PON section, the ONU performs user identification using the LLID. In addition, a device higher than the OLT 100 performs user identification using a VID standardized by IEEE 802.1. The OLT 100 identifies the user using the LLID or VID. When the OLT 100 has a plurality of host device interfaces, the OLT 100 performs user identification using a connection port number and VID with the host device. That is, if the port numbers are different, users having the same VID may be identified as different users.

  The OLT 100 receives a frame in which the LLID is written from the ONU, converts the LLID into a VID, and transfers the frame to the upper network device. In order to perform this conversion, the OLT has an LLID-VID conversion unit that converts LLID into VID. The LLID-VID conversion unit holds an LLID-VID conversion table that describes LLID-VID conversion rules for each user. An OLT having a plurality of ports as an ONU side interface may hold two conversion tables and perform conversion in two steps.

  In FIG. 1, the LLIDs: aaa, bbb, ccc, and ddd of frames # 1, # 2, #n, and #N transmitted from the ONUs 1, 2, n, and N respectively follow the LLID-internal VID conversion table 13. , Internal VID: oo, ppp, qqq, rrr, and then converted to VID: 111, 222, 333, 444 according to the internal VID-VID conversion table 14, and then transferred to the upper network device.

  The LLID-internal VID conversion table 13 and the internal VID-VID conversion table 14 are created as follows. First, the VID value is determined in advance by the network designer, and the operator of the OLT 100 registers the value in the OLT in advance. That is, the value of the VID used in the OLT 100 is determined before connection from the terminal device. The internal VID is automatically given inside the OLT 100 when the OLT operator registers the VID. At this point, the internal VID-VID conversion table 14 is created. Thereafter, when the terminal device is connected, an LLID is assigned to the registration request from the ONU, an internal VID corresponding to the LLID is determined, and the LLID-internal VID conversion table 13 is created using these.

  Here, a mechanism that may cause an erroneous connection will be described. The user A who is using the ONU 1 with the LLID = 1 connected to the terminal device A assigned the MAC address A and the ONU 2 with the LLID = 2 connected to the terminal device B assigned the MAC address B Assume that user B exists and user A and user B are connected to the same ONU side port of the same OLT 100. Further, in the LLID-internal VID conversion table 13 in the OLT 100, it is assumed that internal VID = 100 is registered for LLID = 1, and internal VID = 200 is registered for LLID = 2. In the table 14, it is assumed that VID = 1000 is registered for the internal VID = 100 and VID = 2000 is registered for the internal VID = 200. The host device identifies user A as VID = 1000 and user B as VID = 2000, and performs transfer processing of the received frame. Here, the LLID-VID conversion table (implemented by the LLID-internal VID conversion table 13 and the internal VID-VID conversion table 14) in the OLT 100 fails, and the internal VID = 200 is retained for LLID = 1. Suppose. Such a failure may be caused when particles such as cosmic rays collide with a semiconductor memory that realizes the LLID-VID conversion table, and bit inversion occurs in the memory. In such a case, the upstream frame transmitted from the terminal device A is assigned LLID = 1 in the ONU 1 and is divided into the LLID-VID conversion unit (LLID-internal VID conversion unit and internal VID-VID conversion unit of the OLT 100). May be realized), an incorrect LLID-VID conversion rule is applied and converted to internal VID = 200, which is converted to VID = 2000 and transferred to the upper network device. In this case, the higher-level network device performs a transfer process as a frame from user B (VID = 2000) despite being transmitted from the terminal device of user A. A similar event can occur in the downstream direction.

  FIG. 2 is a block diagram showing a configuration of the OLT 100 according to the first embodiment having a configuration for detecting the event as described above. The right side of the figure is the ONU and terminal device side, and the left side is the upper network side. The OLT 100 receives an upstream frame from the ONU 1. In the upstream frame from the ONU 1, the medium access control (MAC) address of the terminal device and the LLID assigned to the ONU 1 are written. The PON function unit 110 includes an upstream frame receiving unit 111 that receives an upstream frame from the ONU 1 and an LLID-internal VID conversion unit 112 that converts the LLID of the upstream frame into an internal VID. The LLID-internal VID conversion unit 112 holds the LLID-internal VID conversion table 13. Specifically, the LLID-internal VID conversion unit 112 deletes the LLID of the upstream frame and writes the internal VID obtained from the LLID-internal VID conversion table 13 into the frame.

  The concentrator 120 collects a plurality of ports. That is, when the OLT 100 has a plurality of ports as the ONU side interface, the PON function units 110 provided for each port on the ONU side are concentrated via a layer 2 switch (not shown). FIG. 2 shows a case where there is one port and one PON function unit 110. The line concentrator 120 receives an upstream frame from the PON function unit 110, stores the MAC address and internal VID in the received frame in the history information storage unit 140, and the upstream frame internal VID as a host device. Has an internal VID-VID conversion unit 122 that converts the VID used in the VID. The internal VID-VID conversion unit 122 holds an internal VID-VID conversion table 14 describing internal VID and VID conversion rules for each user. Specifically, the internal VID-VID conversion unit 122 overwrites the internal VID written in the frame with the VID obtained from the internal VID-VID conversion table 14.

  The upstream frame transmission unit 130 transmits the frame in which the LLID is converted to the VID to a device on the upper network side. That is, the MAC address of the terminal device and the VID converted from the LLID are written in the transmitted frame.

  The history information storage unit 140 stores a history of combinations of the MAC address of the terminal device in the uplink frame to be transferred and the corresponding internal VID. That is, every time an upstream frame is received and transferred to the host device, the MAC address and the internal VID are cumulatively recorded in the history information storage unit 140. After the printing of the history information recorded in the history information storage unit 140 is completed, the stored MAC address and internal VID may be deleted.

Next, the operation of the OLT 100 will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the OLT 100 of the first embodiment.
The upstream frame reception unit 111 of the OLT 100 receives the upstream frame from the ONU 1 and transfers it to the LLID-internal VID conversion unit 112 (step S100). The LLID-internal VID conversion unit 112 receives the frame from the uplink frame reception unit 111, acquires the internal VID corresponding to the LLID of the received frame from the LLID-internal VID conversion table 13, deletes the LLID in the frame, and acquires The internal VID thus written is written in the frame, and the frame is transferred to the upstream frame receiving unit 121 (step S110). The upstream frame reception unit 121 receives the frame from the LLID-internal VID conversion unit 112, stores the MAC address and internal VID in the received frame in the history information storage unit 140, and stores the frame in the internal VID-VID conversion unit 122. Transfer (step S120). The internal VID-VID conversion unit 122 receives the frame from the upstream frame reception unit 121, acquires the VID corresponding to the internal VID of the received frame from the internal VID-VID conversion table 14, and acquires the internal VID in the frame The frame is overwritten with the VID, and the frame is transferred to the upstream frame transmission unit 130 (step S130). The upstream frame transmission unit 130 receives the frame from the internal VID-VID conversion unit 122 and transmits it to the device on the upper network side (step S140).

  Whether or not a plurality of internal VIDs are recorded for the same MAC address, such as when the maintenance person prints history information stored in the history information storage unit 140 each time a frame is transmitted. If checked, it is possible to confirm the erroneous connection.

  In the OLT 100 configured as described above, the internal VID is accumulated in the history. Since the internal VID is a VID that is assigned internally by the OLT 100 and used internally, there is a problem that the internal VID is different from the VID managed by the device maintainer of the PON system 10. That is, even if the device maintainer can confirm the internal VID of the user suspected of being misconnected, it is difficult to confirm the user information (name, contact information, etc.) corresponding to the internal VID. A configuration corresponding to such a problem will be described.

  FIG. 4 is a block diagram showing the configuration of the OLT 200 of the second embodiment. The PON function unit 110, the concentrator 120, and the upstream frame transmission unit 130 of the OLT 200 are the same as those of the OLT 100 described with reference to FIGS. The history conversion unit (MAC-VID output unit) 210 acquires the history information from the history information storage unit 140, and selects the VID corresponding to the internal VID among the MAC address of the forward uplink frame recorded as the history information and the internal VID. Obtained from the internal VID-VID conversion table 14, the combination of the MAC address and VID is output to the operation system (OPS) output unit 220 and stored in the history information storage unit 140. That is, the history information storage unit 140 stores a combination of a MAC address and a VID in addition to the functions and operations described with reference to FIGS. The history conversion unit 210 may not store the combination of the MAC address and the VID in the history information storage unit 140. The OPS output unit 220 receives the combination of the MAC address and VID output from the history conversion unit 210, and outputs the combination to the OPS of the PON system 10 for storage in an external database or output to a screen. In OPS, when there are a plurality of VIDs with the same MAC address, it is possible to determine that an erroneous connection has occurred.

  In the OLT having a plurality of ports for connection with the host device, the history conversion unit 210 may output a combination of the MAC address, the port number, and the VID. In this configuration, when an internal VID and a VID are assigned to the LLID, a port number is also assigned as a set with the VID, and the port number assigned as a set with the VID is also recorded in the internal VID-VID conversion table 14. To do.

  Next, the operation of the OLT 200 will be described with reference to FIG. FIG. 5 is a flowchart showing the operation of the OLT 200 of the second embodiment. Steps S200 to S240 are the same as steps S100 to S140 in FIG. After the uplink frame transmission unit 130 transmits the frame to the upper network side device in S240, the history conversion unit 210 acquires the history information from the history information storage unit 140, and the MAC address of the transfer uplink frame recorded as the history information Among the internal VIDs, the VID corresponding to the internal VID is acquired from the internal VID-VID conversion table 14, and the combination of the MAC address and the VID is output to the OPS output unit 220 and stored in the history information storage unit 140 (step) S250). The OPS output unit 220 receives the MAC address and VID combination output from the history conversion unit 210, and outputs the combination to the OPS of the PON system 10 (step S260). Step S250 and subsequent steps may be performed immediately after the MAC address and internal VID are stored in the history information storage unit 140 in step 220, or may not be performed every time an uplink frame is transmitted in step 240, but a predetermined number. May be performed every time the frame is transmitted or periodically. In step S250, the history conversion unit 210 may not store the combination of the MAC address and the VID in the history information storage unit 140.

  Acquisition of history information accumulated in the OLT may be performed in response to a request from the OPS. FIG. 6 is a flowchart showing an operation in which the OPS acquires history information from the OLT. The OPS transmits a history acquisition request to the OPS output unit 220 of the OLT 200. The OPS output unit 220 acquires the combination of the MAC address and VID stored in the history information storage unit 140 and transmits the combination to the OPS.

  In the above, history information is stored in the history information storage unit 140 or output to the OPS, and an erroneous connection is detected outside the OLT. In the following, a configuration for detecting an erroneous connection inside the OLT is described. Will be explained. FIG. 7 is a block diagram showing the configuration of the OLT 300 of the third embodiment. The PON function unit 110, the concentrator 120, the upstream frame transmission unit 130, the history information storage unit 140, the history conversion unit 210, and the OPS output unit 220 of the OLT 300 are the same as those of the OLT 200 described with reference to FIGS. It is. The erroneous connection detection unit 310 added in the OLT 300 accesses the history information stored in the history information storage unit 140, and detects different connections when different VIDs are recorded for the same MAC address. Output to the OPS output unit 220. 4 and 5, the history conversion unit 210 of the OLT 200 does not have to store the combination of the MAC address and the VID in the history information storage unit 140, which is the history conversion unit of the OLT 300. 210 is the same. In this case, the erroneous connection detection unit 310 accesses the combination of the MAC address and the internal VID stored in the history information storage unit 140, and different internal VIDs are recorded for the same MAC address. In such a case, an erroneous connection may be detected and output to the OPS output unit 220.

  Next, the operation of the OLT 300 will be described with reference to FIG. FIG. 8 is a flowchart showing the operation of the OLT 300 of the third embodiment. Steps S300 to S320 are the same as steps S200 to S220 in FIG. After the MAC address and internal VID of the frame are stored in the history information storage unit 140 in step 320, the history conversion unit 210 acquires the history information from the history information storage unit 140, and the transfer upstream frame recorded as the history information is recorded. Of the MAC address and the internal VID, the VID corresponding to the internal VID is acquired from the internal VID-VID conversion table 14, and the combination of the MAC address and the VID is output to the OPS output unit 220 and stored in the history information storage unit 140. (Step S330). The erroneous connection detection unit 310 accesses the history information stored in the history information storage unit 140, detects a wrong connection when different VIDs are recorded for the same MAC address, and sends it to the OPS output unit 220. Output (step S340). In step S330, the history conversion unit 210 may not store the combination of the MAC address and the VID in the history information storage unit 140. In this case, the erroneous connection detection unit 310 is stored in the history information storage unit 140. When a combination of the MAC address and the internal VID is accessed and a different internal VID is recorded for the same MAC address, an incorrect connection may be detected and output to the OPS output unit 220. If no erroneous connection is detected, the upstream frame transmission unit 130 transmits the frame received from the internal VID-VID conversion unit 122 to the device on the upper network side (step S350). Detection of erroneous connection may be performed every frame, every predetermined number of frames, or may be performed periodically without performing every frame.

  In the above-described erroneous connection detection, in the transfer device connected to the upper layer of the OLT, the history information storage unit that stores the history of the combination of the MAC address and the corresponding VID in the transfer upstream frame, and a different VID with the same MAC address. You may implement | achieve by providing the misconnection detection part to detect.

  The erroneous connection detection in the above-described embodiment may be realized by a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be a program for realizing a part of the above-described functions, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. You may implement | achieve using programmable logic devices, such as FPGA (Field Programmable Gate Array).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  The present invention can be used in a communication system.

DESCRIPTION OF SYMBOLS 1, 2 ... ONU, 10 ... PON system, 11 ... Optical multiplexing / demultiplexing means, 12 ... Optical fiber transmission line, 13 ... LLID-internal VID conversion table, 14 ... Internal VID-VID conversion table, 100, 200, 300 ... OLT , 110 ... PON function part, 111 ... Uplink frame reception part, 112 ... LLID-internal VID conversion part, 120 ... Concentration part, 121 ... Uplink frame reception part, 122 ... Internal VID-VID conversion part, 130 ... Uplink frame transmission part 140 ... history information storage unit, 210 ... history conversion unit, 220 ... OPS output unit, 310 ... misconnection detection unit

Claims (6)

A passive optical network system comprising: a terminal device to which a medium access control address is assigned; a subscriber line terminal device connected to the terminal device; and a subscriber line terminal device connected to a higher level of the subscriber line terminal device A subscriber line terminal device in
When a registration request is received from the subscriber line terminator, a logical link identifier is allocated to the subscriber line terminator, and when an uplink frame in which the logical link identifier is written is received from the subscriber line terminator, Transfer uplink in which the logical link identifier of the upstream frame is deleted and the internal virtual local area network identifier corresponding to the logical link identifier of the upstream frame is written based on the logical link identifier-internal virtual local area network identifier conversion table to be held A passive optical network function unit for transferring frames;
A history information accumulation unit that accumulates a history of combinations of the medium access control address in the transferred uplink frame and the corresponding internal virtual local area network identifier;
A subscriber line terminal apparatus. Internal virtual local area network identifier relating to correspondence between internal virtual local area network identifier and virtual local area network identifier-internal virtual local area network identifier holding virtual local area network identifier conversion table-virtual local area network identifier converting unit;
A history conversion unit that outputs a combination of a medium access control address and a virtual local area network identifier corresponding to the internal virtual local area network identifier based on the internal virtual local area network identifier-virtual local area network identifier conversion table and the history; ,
An operation system output unit that outputs information of the history conversion unit to an external operation system; and
The subscriber line terminal apparatus according to claim 1, further comprising:   3. The subscriber line terminal apparatus according to claim 2, further comprising an erroneous connection detection unit that detects different virtual local area network identifiers with the same medium access control address in the history stored in the history information storage unit. A terminal device to which a medium access control address is assigned; a subscriber line terminating device connected to the terminal device; and a logical link identifier assigned to the subscriber line terminating device when receiving a registration request from the subscriber line terminating device When the uplink frame in which the logical link identifier is written is received from the subscriber line termination device, the logical link identifier of the uplink frame is deleted, and the logical link identifier-virtual local area network identifier conversion table is retained. A subscriber line terminal station device connected to a higher level of a subscriber line termination device, which transfers a transfer upstream frame in which a virtual local area network identifier corresponding to the logical link identifier of the upstream frame is written based on A passive optical network system comprising a transfer device connected above the subscriber line terminal device. A transfer device in Temu,
A transfer apparatus comprising a history information storage unit for storing a history of combinations of a medium access control address in the transfer uplink frame and the corresponding virtual local area network identifier.   The transfer apparatus according to claim 4, further comprising an erroneous connection detection unit that detects different virtual local area network identifiers with the same medium access control address in the history stored in the history information storage unit. A passive optical network system comprising: a terminal device to which a medium access control address is assigned; a subscriber line terminal device connected to the terminal device; and a subscriber line terminal device connected to a higher level of the subscriber line terminal device An erroneous connection detection method executed by a subscriber line terminal station device in
Assigning a logical link identifier to the subscriber line terminator when receiving a registration request from the subscriber line terminator;
When an uplink frame in which the logical link identifier is written is received from the subscriber line termination device, the logical link identifier of the uplink frame is deleted and held based on a logical link identifier-internal virtual local area network identifier conversion table Transferring a transfer uplink frame in which an internal virtual local area network identifier corresponding to the logical link identifier of the uplink frame is written;
Accumulating a history of combinations of the medium access control address in the transferred forward frame and the corresponding internal virtual local area network identifier;
An erroneous connection detection method.

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