WO2013161374A1

WO2013161374A1 - Optical line terminal

Info

Publication number: WO2013161374A1
Application number: PCT/JP2013/054744
Authority: WO
Inventors: 和俊川上
Original assignee: 三菱電機株式会社
Priority date: 2012-04-24
Filing date: 2013-02-25
Publication date: 2013-10-31
Also published as: JP2015130543A

Abstract

A control board (11) is provided with a management number allocating unit (111) that allocates, at a system switchover time, the same management number to PON interfaces (13a and 13b). Each PON interface (13a and 13b) is provided with: a management information updating unit (131) that, with the establishment of a link from an ONU (3), adds a management number to management information from the ONU (3) and then updates the management information; a management information notifying unit (133) that notifies the other PON interface of the management information; and a data synchronization unit (134) that performs data synchronization for management information that has been notified thereto if the management number of the aforementioned management information matches the management number for the PON interface that the data synchronization unit is a component of, and destroys the aforementioned management information if there is no match.

Description

OLT

The present invention relates to a station side device (OLT) of a PON (Passive Optical Network) system in which a subscriber side device (ONU: Optical Network Unit) is connected via an optical transmission medium and performs Ethernet (Ethernet / registered trademark) communication. This relates to an OLT in which the active and standby optical transceiver boards (PON interfaces) are redundantly configured 1: 1 in Optical Line Terminal.

The PON system is configured by connecting a plurality of ONUs via an optical fiber and an optical splitter to an OLT arranged in a center station. In the data transmission from the OLT to the ONU, all data is transmitted from the OLT to all ONUs, and the ONU receives only the data transmitted to its own terminal and discards other data.

In this PON system that accommodates a plurality of ONUs with a single fiber, if an optical fiber or OLT fails, the optical link is disconnected between the OLT and all ONUs, and the service cannot be provided to the user. Therefore, as a method of reducing the device failure that leads to the service interruption, a method of providing a redundant system by providing a standby system device is widely used. For example, Patent Document 1 discloses a PON system having an N: 1 redundant configuration in which an OLT is provided with one backup optical transceiver panel for N active optical transceiver panels. In this case, the N working optical transceiver boards are connected to a plurality of ONUs via the corresponding N optical fibers and optical couplers. In this case, data sharing or data synchronization is required because the package of the optical transceiver panel having a redundant configuration is different, but it is devised to switch at high speed without data synchronization.

Patent Document 2 discloses a PON system in which an OLT has a 1: 1 redundant configuration of an active optical transceiver and a standby optical transceiver in an optical transceiver panel. In this case, by making the optical transmission / reception unit of the optical transmission / reception board redundant, it is possible to switch the standby optical transmission / reception unit at high speed even if the active optical transmission / reception unit fails, and the service interruption of the subscriber The time is shortened. In this configuration, since control is performed in the same package, there is no need to synchronize data.

JP 2011-124702 A JP 2009-206540 A

On the other hand, in a PON system in which the active and standby optical transmission / reception units are redundantly configured in a 1: 1 optical transmission / reception panel, a long service interruption may occur if the optical transmission / reception panel fails. There is sex. For this reason, in order to reduce the service interruption time and increase the reliability, the PON system has a 1: 1 redundant configuration with one active optical transceiver board and one standby optical transceiver board.

However, when switching from the active system to the standby system in this configuration, the conventional method in which the setting for conducting the main signal is performed after the optical link between the ONU and the standby optical transceiver board is established, the service interruption is performed. There is a problem that the time becomes longer. Therefore, the same setting as the main signal conduction setting performed when the optical link between the active optical transceiver and the ONU is established is set to the standby optical transceiver at the timing set in the active optical transceiver. Also implement. When a failure such as a failure is detected in the optical line and the optical transceiver board, the connection path between the ONU and the OLT is simply switched. As a result, it is possible to change the path from a state where continuity is established between the active optical transmission / reception panel and the ONU to a state where conduction is possible between the standby optical transmission / reception panel and the ONU, and the service interruption time can be reduced.

However, in the conventional configuration, there is no common memory that can share data between the active and standby optical transceiver boards, or a configuration for communication to synchronize data directly between the active and standby systems. For this reason, it is necessary to synchronize data by interposing a control infrastructure having a mechanism for communicating with each infrastructure in a communication path for synchronizing data at the time of redundancy. However, in this case, there is a problem that a state deviation is likely to occur due to a crossing of messages depending on timing.

The present invention has been made to solve the above-described problems. Even in the case where there is no memory and means for direct communication between the optical transceiver boards having a redundant configuration, the optical transceiver boards can be shared. An object of the present invention is to provide an OLT capable of guaranteeing data synchronization.

The OLT according to the present invention comprises an active and standby optical transceiver board for transmitting and receiving optical signals to and from the opposite station, and a control board for switching the system of the optical transceiver board. When the system is switched, a management number allocating unit that newly assigns the same management number to both optical transceiver boards is provided, and the optical transceiver board receives signals from the opposite station when its own equipment is the active system. Along with the link up, the management information related to the opposite station is updated with the management number assigned by the management number assigning unit, and the management information updated by the management information updating unit When the management information is notified from the transmission / reception panel and the management information is notified from the other optical transmission / reception panel, if the management number assigned to the management information matches the management number assigned to the device , The management information Performs data synchronization, in the case of disagreement is that a discarding data synchronization section the management information.

According to the present invention, since it is configured as described above, it is possible to manage data synchronization based on the management number assigned to the active and standby optical transceiver boards, thereby preventing the occurrence of a state deviation. Even in the case of a configuration in which there is no memory that can be shared between optical transmission / reception panels having a redundant configuration and means for direct communication, data synchronization between the optical transmission / reception panels can be ensured.

It is a figure which shows the structure of the PON system which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the control base | substrate in Embodiment 1 of this invention. It is a figure which shows the structure of the optical transmission / reception board in Embodiment 1 of this invention. It is a figure which shows the system switching by the control base | substrate in Embodiment 1 of this invention. It is a sequence which shows the subject in the synchronous process by the conventional OLT. It is a sequence which shows the synchronous process at the time of normal by OLT which concerns on Embodiment 1 of this invention. In the synchronization processing by the OLT according to the first embodiment of the present invention, this is a sequence showing a case where system switching occurs during data synchronization. It is a figure which shows the structure of the optical transmission / reception board in Embodiment 2 of this invention. In the synchronization processing by OLT according to the second embodiment of the present invention, this is a sequence showing a case where system switching occurs during data synchronization.

Hereinafter, in order to explain the present invention in more detail, modes for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
1 is a diagram showing a configuration of a PON system according to Embodiment 1 of the present invention.
As shown in FIG. 1, the PON system includes a plurality of ONUs (opposite stations) 3a to 3c (hereinafter referred to as “unless it is necessary to distinguish”) from an OLT 1 disposed in a center station via an optical splitter 2. (Referred to as ONU3). The optical splitter 2 is a device that branches an optical fiber that is an optical transmission medium for optical signals.

As shown in FIG. 1, the OLT 1 includes a control board 11, an optical splitter 12, and PON interfaces (optical transceiver boards) 13a and 13b. FIG. 1 shows a case where the PON interface 13a is set to ACT (active system) and the PON interface 13b is set to STANBY (standby system).

The control board 11 controls the operation of the optical splitter 12 and the

PON interfaces

13a and 13b. The internal configuration of the control board 11 will be described later.

The optical splitter 12 is a device that branches an optical fiber that is an optical transmission medium for optical signals. The optical splitter 12 is connected to the control board 11 by a control line, and can switch the

PON interfaces

13a and 13b to be connected in accordance with control from the control board 11.

The

PON interfaces

13a and 13b are bases for transmitting and receiving optical signals to and from the ONU 3 via the optical splitter 12. The

PON interfaces

13a and 13b are connected to the control board 11 via control lines, and system switching (ACT / STANDBY setting) is performed in accordance with control from the control board 11. The internal configuration of the

PON interfaces

13a and 13b will be described later.

Next, the internal configuration of the control board 11 will be described with reference to FIG.
As shown in FIG. 2, the control board 11 includes a management number assigning unit 111 and a system switching unit 112.

The management number assigning unit 111 newly assigns the same management number to both the

PON interfaces

13a and 13b when the base is started up and when the system of the

PON interfaces

13a and 13b is switched by the system switching unit 112. .
The system switching unit 112 causes the

PON interfaces

13a and 13b to perform system switching when a failure is detected by the failure detection unit 132 of the active PON interface.

Next, the internal configuration of the

PON interfaces

13a and 13b will be described with reference to FIG. Hereinafter, the PON interface 13a will be described, but the same applies to the PON interface 13b.
As illustrated in FIG. 3, the PON interface 13 a includes a management information update unit 131, a failure detection unit 132, a management information notification unit 133, and a data synchronization unit 134.

The management information update unit 131 updates the management information related to the ONU 3 with the latest management number assigned by the management number assigning unit 111 in accordance with the link up from the ONU 3 when the own device is the active system. To do.
The failure detection unit 132 detects a failure when the own device is an active system. Here, when detecting a failure, the failure detection unit 132 notifies the system switching unit 112 of the control infrastructure 11 to that effect.

The management information notification unit 133 notifies synchronization data indicating the management information updated by the management information update unit 131 to the other PON interface. The synchronization data is assigned the same management number as the management information.
When synchronization data is notified from the management information notification unit 133 of the other PON interface, the data synchronization unit 134 compares the management number assigned to the synchronization data with the management number assigned to the own device, If they match, the synchronization data is used to synchronize the management information. If they do not match, the synchronization data is discarded.

Next, a case where the system is switched from the state shown in FIG. 1 in the PON system configured as described above will be described with reference to FIG.
In this case, the system switching unit 112 of the control board 11 first outputs a control instruction 1121 to the optical splitter 12 to switch the connection destination of the optical splitter 12. As a result, the optical splitter 12 switches the connection destination from the PON interface 13a shown in FIG. 1 to the PON interface 13b shown in FIG.
Then, after the path of the optical splitter 12 is switched, the system switching unit 112 of the control board 11 changes the setting of the PON interface 13a from ACT to STANDBY by outputting a switching control instruction 1122 to the PON interface 13a. Let Further, the system switching unit 112 of the control board 11 outputs a switching control instruction 1123 to the PON interface 13b to change the setting from STANDBY to ACT. Thus, the system switching can be completed.

Next, in order to show the effect of the synchronization processing of the OLT 1 according to the present embodiment, a problem in the synchronization processing of the conventional OLT 100 will be described with reference to FIG. In the following, it is assumed that the PON interface 1003a of the OLT 100 is set to ACT and the PON interface 1003b is set to STANBY as an initial state.
First, when an optical fiber is connected to the ONU 3, the ONU 3 performs link-up with respect to the PON interface 1003a set to ACT in the OLT 100.

Then, in response to the link up from the ONU 3, in the OLT 100, first, the PON interface 1003a updates management information such as a MAC address based on the information of the ONU 3 (step ST501).
Next, the PON interface 1003a performs conduction setting for the ONU 3 (step ST502).

Further, the PON interface 1003a performs data synchronization with the PON interface 1003b set to STANBY in order to enable system switching (step ST503). At this time, since the PON interface 1003a is not connected to the PON interface 1003b, the updated management information is sent as synchronization data via the control board 1001. Thereafter, the PON interface 1003b updates the management information based on the synchronization data.

On the other hand, if a failure is detected in the PON interface 1003a set to ACT, it is necessary to switch the system with priority over other processing in order to shorten the service interruption time.
Therefore, for example, when a failure is detected during transmission of synchronous data as shown in FIG. 5, the PON interface 1003a indicates that the failure has been detected with respect to the control board 1001 in preference to this synchronous data notification. Notification (failure detection notification) is performed (step ST504). Therefore, in this case, since synchronous data notification is interrupted, data synchronization by the PON interface 1003b is not performed.

Next, the control board 1001 that has received the failure detection notification outputs a switching control instruction for changing the setting to STANBY to the PON interface 1003a in preference to other processes (step ST505). As a result, the PON interface 1003a changes the setting from ACT to STANDBY.
Next, the control board 1001 outputs a switching control instruction for changing the setting to the ACT to the PON interface 1003b (step ST506). As a result, the PON interface 1003b changes the setting from STANDBY to ACT.

Then, when the system of the

PON interfaces

1003a and 1003b is switched by the control board 1001, the ONU 3 performs link-up with respect to the PON interface 1003b newly set to ACT.
Next, since the PON interface 1003b newly set to ACT has not updated the management information in advance, the management information is updated in response to the link up from the ONU 3 (step ST507).

On the other hand, from the PON interface 1003a, synchronous data notification that has been postponed by the above-described system switching is performed. However, since the PON interface 1003b has already updated the management information, the synchronization data is not necessary. And this synchronous data can be a factor of a state gap.

Next, the synchronization processing of the OLT 1 according to the present embodiment will be described with reference to FIG. First, the synchronization process at the normal time will be described. In the following, it is assumed that, as shown in FIG. 1, the PON interface 13a is set to ACT and the PON interface 13b is set to STANBY as an initial state.
In the synchronization processing of the OLT 1, as shown in FIG. 6, first, the management number assigning unit 111 of the control board 11 has the PON interface 13a set to ACT and the PON interface 13b set to STANBY when the board is activated. Are assigned the same management number (= 1) (steps ST601 and ST602).
Thereafter, when an optical fiber is connected to the ONU 3, the ONU 3 performs link-up with respect to the PON interface 13a set to ACT in the OLT 1.

Then, triggered by the link up from the ONU 3, the management information updating unit 131 of the PON interface 13a updates the management information such as the MAC address based on the information of the ONU 3 (step ST603). At this time, the management information update unit 131 adds the management number (= 1) assigned by the control board 11 to the management information.
Next, the PON interface 13a performs continuity setting for the ONU 3 (step ST604).

Also, the management information notification unit 133 of the PON interface 13a performs data synchronization with the PON interface 13b set to STANBY in order to enable system switching (step ST605). At this time, since the PON interface 13a is not connected to the PON interface 13b as shown in FIG. 1, the updated management information is sent as synchronization data via the control board 11. Therefore, the management number (= 1) added to the management information is attached to the synchronization data.

Next, the data synchronization unit 134 of the PON interface 13b set to STANBY compares the management number assigned to the synchronization data from the PON interface 13a set to ACT with the management number assigned to the own device. To do. Here, in the example shown in FIG. 6, since the management number (= 1) of the synchronization data matches the management number (= 1) of the PON interface 13b, the data synchronization unit 134 uses this synchronization data. The management information is updated (step ST606).
By operating as described above, in normal times (when no failure is detected), the management information updated in the PON interface 13a set in the ACT is updated to the PON interface 13b set in the STANBY. However, it can be updated and data synchronization can be performed.

Next, a method according to this embodiment for solving the problem of FIG. 5 will be described with reference to FIG. Note that the processing from step ST701 to step 705 shown in FIG. 7 is the same as the processing from step ST601 to step 605 shown in FIG.

Similarly to FIG. 5, when a failure is detected by the failure detection unit 132 of the PON interface 13a during transmission of the synchronization data, the failure detection unit 132 gives priority to the control infrastructure 11 over this synchronization data notification. Notification (failure detection notification) indicating that a failure has been detected is performed (step ST706). Therefore, in this case, since synchronous data notification is interrupted, data synchronization by the PON interface 13b is not performed.

Next, the system switching unit 112 of the control board 11 that has received the failure detection notification outputs a switching control instruction for changing the setting to STANBY to the PON interface 13a in preference to other processing (step ST707). ). At this time, the management number assigning unit 111 increments a new management number (= 2) in the switching control instruction. As a result, the PON interface 13a changes the setting from ACT to STANDBY and is assigned a new management number (= 2).
Next, the system switching unit 112 of the control board 11 outputs a switching control instruction for changing the setting to ACT to the PON interface 13b set to STANBY (step ST708). At this time, the management number assignment unit 111 increments the same management number (= 2) as the new management number assigned to the PON interface 13a in the switching control instruction. As a result, the PON interface 13b is changed from STANDBY to ACT and a new management number (= 2) is assigned.

Then, when the system of the PON interfaces 13a and 13b is switched by the control board 11, the ONU 3 performs link-up with respect to the PON interface 13b newly set to ACT.
Next, since the management information update unit 131 of the PON interface 13b newly set to ACT has not updated the management information in advance, the management information is updated in response to a link up from the ONU 3 (step ST709). At this time, the management information update unit 131 adds the management number (= 2) assigned by the control board 11 to the management information.

On the other hand, from the management information notification unit 133 of the PON interface 13a, synchronous data notification that has been postponed by the above-described system switching is performed. Note that the management number (= 1) added to the management information is attached to the synchronization data.
Next, the data synchronization unit 134 of the PON interface 13b set to STANBY compares the management number assigned to the synchronization data from the PON interface 13a set to ACT with the management number assigned to the own device. To do. Here, in the example shown in FIG. 7, since the management number (= 1) of the synchronization data is different from the management number (= 2) of the PON interface 13b, the data synchronization unit 134 determines that the management numbers do not match. Then, the synchronous data is discarded (step ST710). Thereby, generation | occurrence | production of a state shift can be suppressed.

As described above, according to the first embodiment, since the same management number is assigned when the system is switched from the active system to the standby system, the link with the ONU 3 is established in the active system, Even if a cross sequence that causes system switching occurs during transmission of a message (synchronization data) for synchronizing link establishment information (management information) to the standby system, each

PON interface

13a, 13b Since the management number is updated to a new management number, it is possible to detect and discard a message that causes a state mismatch, and to ensure data synchronization between the redundantly configured

PON interfaces

13a and 13b.

Embodiment 2. FIG.
In the first embodiment, the case where the data synchronization of the PON interfaces 13a and 13b and the link-up of the ONU 3 do not intersect has been shown. On the other hand, Embodiment 2 shows a case where data synchronization and ONU3 link-up intersect.
FIG. 8 is a diagram showing a configuration of the PON interface 13a according to the second embodiment of the present invention. The PON interface 13a in the second embodiment shown in FIG. 8 is obtained by adding a reset unit 135 to the PON interface 13a in the first embodiment shown in FIG. Other configurations are the same, and the same reference numerals are given and description thereof is omitted. The internal configuration of the PON interface 13b is the same as that of the PON interface 13a, and the description thereof is omitted.

The reset unit 135 stops the data synchronization by the data synchronization unit 134 and resets the ONU 3 when there is a link up from the ONU 3 during the data synchronization by the data synchronization unit 134.

Next, in the OLT 1 configured as described above, a method according to this embodiment for solving the problem of FIG. 5 will be described with reference to FIG. FIG. 9 shows a case where the data synchronization of the PON interfaces 13a and 13b and the link up of the ONU 3 intersect.

The difference from the synchronization processing of the first embodiment shown in FIG. 7 is that the synchronization data is first notified before the link-up of the ONU 3 (step ST905). Then, data synchronization and link-up of ONU 3 compete (step ST909).

In this case, as shown in FIG. 9, when a failure occurs, the system switching unit 112 of the control infrastructure 11 issues a switching control instruction to the PON interfaces 13a and 13b, respectively (steps ST907 and 908). Thereafter, when the synchronization data is notified from the management information notification unit 133 of the PON interface 13a, the data synchronization unit 134 of the PON interface 13b starts data synchronization (step ST909). However, the linkup from the ONU 3 is performed immediately thereafter, so that the reset unit 135 of the PON interface 13b performs the management information update triggered by the data synchronization notification and the management performed triggered by the linkup of the ONU3. In order to maintain consistency with the information update, the data synchronization by the data synchronization unit 134 is stopped and the ONU 3 is reset (step ST910).
Thereafter, in the ONU 3, after resetting, the PON interface 13b set in ACT is linked up again. Therefore, the management information update unit 131 of the PON interface 13b can update the management information with the link up from the ONU 3 as a trigger.

As described above, according to the second embodiment, when there is a link up from the ONU 3 during data synchronization, the data synchronization is stopped and the ONU 3 is reset. Even in the case of contention with link-up, it is possible to prevent the occurrence of state inconsistency and to ensure data synchronization between the redundantly configured

PON interfaces

13a and 13b.

In the present invention, within the scope of the invention, any combination of the embodiments, any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

The OLT according to the present invention is configured such that the same management number is assigned when the system is switched from the active system to the standby system, and data synchronization is performed based on the management numbers assigned to the active and standby optical transceiver boards. Therefore, even if the configuration does not include a memory that can be shared between redundant optical transceiver panels and means for direct communication, the data between the optical transceiver boards can be managed. Since synchronization can be ensured, it is suitable for use in an OLT in which the active and standby optical transmission / reception panels have a redundant configuration of 1: 1.

1 OLT, 2 Optical splitter, 3, 3a-3c ONU (opposite station), 11 Control board, 12 Optical splitter, 13a, 13b Optical transceiver board (PON interface), 111 Management number assignment unit, 112 system switching unit, 131 management Information update unit, 132 failure detection unit, 133 management information notification unit, 134 data synchronization unit, 135 reset unit.

Claims

In an OLT comprising an active and standby optical transceiver board for transmitting and receiving optical signals to and from an opposite station, and a control board for switching the optical transceiver board system,
The control infrastructure is
When the system of the optical transceiver board is switched, a management number assigning unit that newly assigns the same management number to the two optical transceiver boards is provided,
The optical transceiver board is:
A management information updating unit that updates management information related to the opposite station with the management number assigned by the management number assigning unit in association with link-up from the opposite station when the own apparatus is an active system; ,
A management information notification unit that notifies the management information updated by the management information update unit to the other optical transceiver board;
When the management information is notified from the other optical transceiver panel, if the management number assigned to the management information matches the management number assigned to the device, the management information is synchronized and the data does not match. In this case, the OLT includes a data synchronization unit that discards the management information.
A reset unit for stopping data synchronization by the data synchronization unit and resetting the counter station when there is a link up from the opposite station during data synchronization of management information by the data synchronization unit; The OLT according to claim 1, wherein