JP2024070927A - Link-up control method, station side device and OLT - Google Patents

Abstract

The present invention makes it possible to execute a link-up process while updating firmware of an OLT.
[Solution] A link-up control method for controlling link-up of home-side devices by a station-side device having multiple OLTs, comprising the steps of: determining a first OLT among the multiple OLTs as an alternative destination for link-up processing for linking up home-side devices under the second OLT by a second OLT that is capable of communicating with the first OLT among the multiple OLTs and has a firmware update scheduled; configuring the first OLT so that it can substitute for the link-up processing of the second OLT; updating the firmware by the second OLT; and returning the subject of execution of the link-up processing from the first OLT to the second OLT after the firmware update.
[Selected Figure] Figure 1

Description

This disclosure relates to a link-up control method, a station device, and an OLT.

PON (Passive Optical Network) is one of the configurations that realize FTTH (Fiber To The Home), which provides network access services to each household via optical fiber. The feature of PON is that it can provide optical access services at low cost by sharing part of the optical fiber connecting the optical network unit (ONU (Optical Network Unit)) installed at the home side and the optical line terminal (OLT (Optical Line Terminal)) installed at the central office side for communication.

Network systems, including FTTH, often require the ability to add new functions and fix problems. One method for implementing such functions is to update firmware executed by the CPU (Central Processing Unit) in network equipment. In this specification, "firmware" includes program code executed by the CPU inside communication equipment (regardless of whether it is an OLT or ONU).

While updating the OLT firmware, there is a possibility that the OLT processing may stop. To solve this problem, for example, JP 2014-78784 A (Patent Document 1) proposes configuring the OLT with an upper processing unit and a lower processing unit. With this configuration, the lower processing unit can maintain communication between the OLT and the ONU while the firmware of the upper processing unit is being updated.

JP 2014-78784 A

In the configuration proposed in JP 2014-78784 A, while the firmware of the upper processing unit of the OLT is being updated, the upper processing unit cannot execute processing for linking up the ONU. However, JP 2014-78784 A does not explain this problem, and therefore does not provide a solution to it.

The objective of this disclosure is to provide a technique that enables link-up processing to be performed while updating OLT firmware.

The link-up control method disclosed herein is a link-up control method for controlling link-up of home-side devices by a station-side device having multiple OLTs, and includes the steps of: determining a first OLT of the multiple OLTs as an alternative destination for link-up processing for linking up home-side devices under the second OLT by a second OLT that can communicate with the first OLT of the multiple OLTs and has a firmware update scheduled; setting the first OLT so that it can substitute for the link-up processing of the second OLT; updating the firmware by the second OLT; and returning the subject of execution of the link-up processing from the first OLT to the second OLT after the firmware update.

The station side device of the present disclosure includes a plurality of OLTs, including a first OLT and a second OLT communicably connected to the first OLT, the second OLT has firmware, and when the second OLT is scheduled to have its firmware updated, the first OLT is determined as an alternative destination for link-up processing by the second OLT for linking up a home side device under the second OLT, the first OLT can take over the link-up processing by taking over the settings for the link-up processing by the second OLT from the second OLT, and when the second OLT updates its firmware, the main entity for executing the link-up processing is returned from the first OLT to the second OLT.

The OLT disclosed herein comprises an upper processing unit having firmware, and a lower processing unit capable of communicating with the upper processing unit and other OLTs and also responsible for communication with home devices. When there is a plan to update the firmware of the upper processing unit, the upper processing unit substitutes the link-up process for linking up the home devices with the other OLT via the lower processing unit, and after the firmware is updated, the execution entity of the link-up process is returned from the other OLT to the upper processing unit.

According to the present disclosure, it is possible to perform link-up processing while updating the OLT firmware.

FIG. 1 is a diagram showing an outline of the configuration of a PON system according to one embodiment of the present disclosure. FIG. 2 is a functional block diagram of the upper level processing unit 111 shown in FIG. FIG. 3 is a sequence diagram for explaining a problem that may occur when performing a link-up process during an uninterruptible firmware update. FIG. 4 is a sequence diagram for illustrating a link-up process during an uninterruptible firmware update according to an embodiment of the present disclosure. FIG. 5 is a diagram for explaining the flow of link-up processing in normal times. FIG. 6 is a diagram for explaining a link-up control method for achieving both firmware update and link-up processing. FIG. 7 is a sequence diagram illustrating the overall flow of the link-up process according to the present embodiment. FIG. 8 is a sequence diagram illustrating an example of a link-up process. FIG. 9 is a diagram for explaining information transmitted via the communication setting unit. FIG. 10 is a diagram showing an example of a format of a frame that the communication processing unit exchanges with the ONU.

[Description of the embodiments of the present disclosure]
First, the embodiments of the present disclosure will be listed and described.

(1) A link-up control method according to an embodiment of the present disclosure is a link-up control method for controlling link-up of home-side devices by a station-side device having multiple OLTs, and includes the steps of: determining a first OLT of the multiple OLTs as an alternative destination for link-up processing for linking up home-side devices under the second OLT by a second OLT that can communicate with the first OLT of the multiple OLTs and has a firmware update scheduled; setting the first OLT so that it can take over the link-up processing of the second OLT; updating the firmware by the second OLT; and returning the subject of execution of the link-up processing from the first OLT to the second OLT after the firmware update.

According to this configuration, while the second OLT is updating its firmware, the first OLT can execute the link-up process for the home devices under the second OLT in place of the second OLT. Therefore, the link-up process can be executed while the firmware of the second OLT is being updated. Note that the terms "first" and "second" are used for convenience to refer to the OLT that is the alternative destination for the link-up process and the OLT that is scheduled to have its firmware updated.

(2) The link-up control method of (1) above further includes a step in which, while the first OLT is an alternative destination for the link-up process of the second OLT, the first OLT determines whether the home-side device that is the subject of the link-up process is subordinate to the first OLT or the second OLT.

According to the above configuration, while the first OLT is an alternative destination for the link-up process of the second OLT, the first OLT needs to support both link-up of the ONUs under the first OLT and link-up of the ONUs under the second OLT. Link-up can be performed normally by determining whether the ONU that is the target of the link-up process is a home-side device under the control of the first OLT or the second OLT.

(3) In the link-up control method of (2) above, the step of setting the first OLT includes a step of setting a notification path so as to forward a link-up notification sent from the home-side device that is the target of the link-up process to the second OLT to the first OLT, and the step of determining includes a step of determining, when the first OLT receives a link-up notification from the second OLT, based on information included in the link-up notification that the home-side device that is the target of the link-up process is a home-side device under the control of the second OLT.

According to the above configuration, the first OLT can determine whether the ONU that is the target of the link-up process is a home-side device under the control of the first OLT or the second OLT.

(4) A station side device according to an embodiment of the present disclosure includes a plurality of OLTs, the plurality of OLTs including a first OLT and a second OLT communicably connected to the first OLT, the second OLT having firmware, when the second OLT is scheduled to have its firmware updated, the first OLT is determined as an alternative destination for link-up processing by the second OLT for linking up a home side device under the second OLT, the first OLT is capable of taking over the link-up processing by taking over the settings for the link-up processing by the second OLT from the second OLT, and when the second OLT updates its firmware, the entity responsible for executing the link-up processing is returned from the first OLT to the second OLT.

With this configuration, while the second OLT is updating the firmware, the first OLT can take over from the second OLT and execute link-up processing for the home devices under the control of the second OLT.

(5) In the station side device of (4) above, each of the first OLT and the second OLT has an upper processing unit and a lower processing unit that can communicate with the upper processing unit and is responsible for communication with the home side device, the lower processing unit of the first OLT and the lower processing unit of the second OLT are connected to each other so that they can communicate with each other, and when there is a plan to update the firmware of the upper processing unit of the second OLT, the upper processing unit of the first OLT is configured to be able to replace the link-up processing by receiving settings for the link-up processing by the second OLT from the second OLT.

According to this configuration, when the firmware of the upper processing unit of the second OLT is updated, the upper processing unit of the first OLT can receive settings for link-up processing by the second OLT via the lower processing unit of the second OLT and the lower processing unit of the first OLT. As a result, the upper processing unit of the first OLT can execute link-up processing for linking up the ONUs under the second OLT in place of the upper processing unit of the second OLT.

(6) In the station device of (5) above, when the upper processing unit of the first OLT receives a link-up notification from the lower processing unit of the first OLT while the first OLT is the alternative destination for the link-up processing of the second OLT, the upper processing unit of the first OLT determines, based on the information included in the link-up notification, whether the home-side device that is the subject of the link-up processing is subordinate to the first OLT or the second OLT.

According to the above configuration, the upper processing unit of the first OLT determines whether the ONU that is the target of the link-up process is a home-side device under the control of the first OLT or the second OLT. This allows the link-up to be performed normally.

(7) In the station side device of (5) or (6) above, the lower processing unit of the second OLT sets a forwarding path for the link-up notification so that, when the first OLT can take over the link-up process, the link-up notification for linking up the home side device under the control of the second OLT is forwarded to the upper processing unit of the first OLT.

According to this configuration, the lower processing unit of the second OLT transfers a notification regarding the link-up of an ONU under the second OLT to the upper processing unit of the first OLT instead of the upper processing unit of the second OLT. This allows the upper processing unit of the first OLT to execute link-up processing for linking up an ONU under the second OLT instead of the upper processing unit of the second OLT.

(8) An OLT according to an embodiment of the present disclosure includes an upper processing unit having firmware, and a lower processing unit that is capable of communicating with the upper processing unit and other OLTs and is responsible for communication with home-side devices. When there is a plan to update the firmware of the upper processing unit, the upper processing unit substitutes the link-up process for linking up the home-side devices with another OLT via the lower processing unit, and after the firmware is updated, the execution entity of the link-up process is returned from the other OLT to the upper processing unit.

With this configuration, it is possible to provide an OLT that can have another OLT take over the link-up process for the home devices under its control while the firmware is being updated.

[Details of the embodiment of the present disclosure]
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

In the description of the embodiments of the present disclosure, "link-up processing" refers to processing executed by the OLT to establish a logical link between the ONU and the OLT. In the embodiments of the present disclosure, "link-up processing" is not limited to link-up, and may include, for example, authentication processing, normality confirmation, and other processing.

Figure 1 is a diagram showing an outline of the configuration of a PON system according to one embodiment of the present disclosure. As shown in Figure 1, the PON system 10 includes an optical line terminal 100. The optical line terminal 100 is a terminal device installed, for example, in a relay station of a telecommunications carrier. Although not explicitly shown in Figure 1, the optical line terminal 100 is connected to a higher-level network.

In an embodiment of the present disclosure, the optical line terminal 100 includes a plurality of OLTs. As shown in FIG. 1, the plurality of OLTs include OLTs 101 and 102. In an embodiment of the present disclosure, the form of the OLTs is not particularly limited. For example, according to one embodiment of the present disclosure, the OLTs 101 and 102 are small, general-purpose modules. According to such an embodiment, for example, each of the OLTs 101 and 102 may be realized in the form of a line unit housed in a housing. Alternatively, each of the OLTs 101 and 102 may be realized in the form of a line card.

For convenience of illustration, the number of OLTs provided in the optical line terminal 100 in FIG. 1 is two. However, the optical line terminal 100 may be configured to include multiple OLTs. Therefore, the optical line terminal 100 may include three or more OLTs.

Each of OLTs 101 and 102 is connected to an ONU via an optical line. In a PON system, a single optical line from the OLT is branched by an optical splitter into multiple lines connected to each ONU. In the configuration shown in FIG. 1, OLT 101 is connected to M ONUs (ONUs 211-21M) via optical line 11, and OLT 102 is connected to N ONUs (ONUs 221-22N) via optical line 12. Here, M and N represent any integer greater than or equal to 1. M and N may be different numbers or the same number. Each of ONUs 211-21M is connected to OLT 101 via optical line 11, so they can be called "ONUs under OLT 101." Similarly, each of ONUs 221 to 22N is connected to OLT 102 via optical line 12, and can therefore be called an "ONU under OLT 102."

OLT101 and OLT102 are connected to each other so that they can communicate with each other. This allows OLT101 and OLT102 to send and receive control signals to each other.

Each OLT includes an upper processing unit and a lower processing unit. The upper processing unit has firmware and is responsible for the upper layer of the layered communication protocol. The lower processing unit is controlled by the upper processing unit and is responsible for the lower layer of the layered communication protocol. The "layered communication protocol" is, for example, a communication protocol that conforms to the OSI (Open Systems Interconnection) reference model. In this case, the "upper layer" is, for example, the fourth layer (transport layer) and layers above it, and the "lower layer" is, for example, the first layer (physical layer), second layer (data link layer), and third layer (network layer) of the OSI reference model. The data link layer protocol includes, but is not limited to, the MPCP (Multi-Point Control Protocol) and the OAM (Operations, Administration and Maintenance) protocol.

The lower processing unit is capable of communicating with the upper processing unit and is responsible for communication with the ONU. The lower processing unit is configured to be able to continue communication with the ONU even if some or all of the processing in the upper processing unit is temporarily stopped.

Specifically, the OLT 101 includes an upper processing unit 111 and a lower processing unit 112. The lower processing unit 112 includes a PON interface (I/F) unit 113, a communication processing unit 114, and an upper interface (I/F) unit 115.

The PON interface unit 113 is connected to the optical line 11 (optical fiber) and converts the optical signal (upstream signal) received from the optical line 11 into an electrical signal. On the other hand, the PON interface unit 113 converts the downstream signal, which is an electrical signal input from the communication processing unit 114, into an optical signal and sends the optical signal to the optical line 11.

The communication processing unit 114 communicates with the upper processing unit 111. The protocol used for communication between the upper processing unit 111 and the communication processing unit 114 is, for example, TCP/IP. When the communication processing unit 114 determines that an upstream signal transmitted from an ONU under the OLT 101, i.e., any of ONUs 211 to 21N, is a data signal, it executes various processes for transmitting the data signal from the OLT 101 to a higher-level network (not shown). On the other hand, the communication processing unit 114 executes various processes for transmitting a downstream signal (data signal) sent from the higher-level network to the OLT 101 via the optical line 11 to an ONU under the OLT 101.

Furthermore, when a control frame is transmitted to the OLT 101, the communication processing unit 114 transfers the control frame to the upper processing unit 111. When a control frame is to be transmitted from the OLT 101 to an ONU, the communication processing unit 114 receives the control frame to be sent to the ONU from the upper processing unit 111 and executes processing to send the control frame to the optical line 11.

The OLT 102 includes an upper processing unit 121 and a lower processing unit 122. The lower processing unit 122 includes a PON interface (I/F) unit 123, a communication processing unit 124, and an upper interface (I/F) unit 125. The functions of the upper processing unit 121 and the lower processing unit 122 are the same as the functions of the upper processing unit 111 and the lower processing unit 112 described above, respectively. In addition, the functions of the PON interface unit 123, the communication processing unit 124, and the upper interface unit 125 in the lower processing unit 122 are the same as the functions of the PON interface unit 113, the communication processing unit 114, and the upper interface unit 115 described above, respectively. Therefore, detailed descriptions of the functions of the upper processing unit 121 and the lower processing unit 122 of the OLT 102 will not be repeated hereafter.

The lower processing unit 112 of OLT 101 and the lower processing unit 122 of OLT 102 are connected to each other so that they can communicate with each other. For example, the control ports of the lower processing units 112 and 122 are connected to each other. This makes it possible to send and receive control signals between OLT 101 and OLT 102.

Figure 2 is a functional block diagram of the upper processing unit 111 shown in Figure 1. Note that the functional blocks of the upper processing unit 121 are similar to those of the upper processing unit 111, so in the following, the functional blocks of the upper processing unit 111 will be described as a representative.

As shown in FIG. 2, the upper processing unit 111 includes an update unit 131, a storage unit 132, and a control unit 133. The update unit 131 updates the firmware held by the upper processing unit 111 to new firmware. Specifically, the update unit 131 obtains new firmware from outside the OLT 101. The new firmware is provided to the OLT 101, for example, via a network. The update unit 131 temporarily stores the new firmware in the storage unit 132. Next, the update unit 131 reads the new firmware from the storage unit 132, for example, in accordance with instructions from an operator, and updates the current firmware to the new firmware.

The memory unit 132 stores various information necessary for the processing performed by the upper processing unit 111. For example, the memory unit 132 stores information related to the settings of the OLT 101.

The control unit 133 executes various processes based on the information stored in the memory unit 132 or the information sent from the lower processing unit 112. For example, the control unit 133 executes link-up processing for linking up the ONU. When firmware is updated, the control unit 133 performs settings related to updating the functions of the lower processing unit 112.

The firmware of the upper processing unit may be updated to new firmware in order to add new functions to the OLT or to repair operational problems of the OLT. While the firmware is being updated, all or some of the functions of the upper processing unit cannot be executed. By configuring the OLT with an upper processing unit and a lower processing unit, the lower processing unit can continue to communicate with the ONU even during the firmware update period of the upper processing unit. This makes it possible to prevent data communication from being stopped due to a firmware update. Updating the firmware of the upper processing unit while allowing communication by the lower processing unit to be maintained is referred to below as an "uninterrupted firmware update."

Figure 3 is a sequence diagram to explain problems that may occur when performing link-up processing during an uninterruptible firmware update. As shown in Figure 3, when the OLT is started, the upper processing unit is initialized (step S1). Next, the upper processing unit sets up communication for the lower processing unit (step S2). This enables the lower processing unit to communicate with the upper processing unit and the ONUs under the OLT.

Then, the firmware (indicated as "FW" in FIG. 2) of the upper processor is updated (step S3). Meanwhile, assume that the need to link up the ONU arises. However, while the upper processor is updating the firmware, the upper processor cannot execute the link-up process.

After the firmware is updated, the upper processing unit is restarted (step S4). The upper processing unit cannot execute link-up processing while it is being restarted. After the restart, the upper processing unit is initialized, and the functions of the upper processing unit are updated (step S5). After the restart, the upper processing unit can execute link-up processing.

As such, in an OLT that is scheduled to have a firmware update, there is a possibility that the link-up process cannot be performed at least from the start of the firmware update to the end of rebooting. The embodiment of the present disclosure solves such a problem.

Figure 4 is a sequence diagram for illustrating link-up processing during uninterruptible firmware update according to an embodiment of the present disclosure. The "upper processing unit 1" shown in Figure 3 is one of the upper processing units (upper processing units 111, 121) of each of the OLTs 101, 102, and the "upper processing unit 2" is the other of the upper processing units 111, 121. For example, the "upper processing unit 1" is the upper processing unit 111, and the "upper processing unit 2" is the upper processing unit 121. In this case, the "lower processing unit 1" shown in Figure 3 is the lower processing unit 112 of the OLT 101.

As in the sequence shown in FIG. 3, first, OLTs 101 and 102 are started and upper processors 111 and 121 are initialized (steps S1 and S1A). Next, upper processors 111 and 121 set up communication with their corresponding lower processors (steps S2 and S2A).

While the firmware is being updated in the upper processing unit 111 (step S3), and while the upper processing unit 111 is restarted after the firmware is updated (step S4), the upper processing unit 111 cannot execute the process for linking up the ONUs under the OLT 101. However, in this case, the upper processing unit 121 executes the link-up process instead of the upper processing unit 111. This makes it possible to link up the ONUs under the OLT 101.

In addition, after the upper processing unit 111 is initialized, the upper processing unit 111 can execute link-up processing through the lower processing unit 112 (step S5).

In this manner, in this embodiment, two OLTs, which basically operate as independent OLTs, link their respective upper-level processing units when updating firmware. When the firmware of one upper-level processing unit is being updated, the link-up process by that upper-level processing unit is performed by the other upper-level processing unit instead. This not only enables uninterrupted firmware updates, but also makes it possible to perform link-up processing while the firmware is being updated.

Next, the link-up process by the OLT will be explained in detail. Figure 5 is a diagram for explaining the flow of the link-up process under normal circumstances. "Normal circumstances" refers to a situation where there is no firmware update. A link-up event occurs, for example, when an ONU is connected to an optical line for the first time or when the ONU is rebooted.

Let us assume that a link-up event occurs in an ONU under OLT 101. In this case, the ONU transmits a link-up signal to OLT 101 via optical line 11. The link-up signal is received by lower processing unit 112.

In the lower processing unit 112, the communication processing unit 114 receives the link-up signal via the PON interface unit 113 and transfers a link-up notification to the upper processing unit 111. When the upper processing unit 111 receives the link-up notification from the lower processing unit 112, it refers to the setting information 134 and executes link-up processing for linking up the ONU.

The setting information 134 is stored inside the OLT 101 (for example, the storage unit 132 shown in FIG. 2). The setting information 134 may include information regarding communication settings between the OLT 101 and the ONUs subordinate thereto.

Similarly, when a link-up event occurs in an ONU under OLT 102, the ONU transmits a link-up signal to optical line 12. In this case, the link-up signal is received by lower-level processing unit 122 of OLT 102. When the communication processing unit 124 receives the link-up signal, it transmits a link-up notification to upper-level processing unit 121. When the upper-level processing unit 121 receives the link-up notification, it refers to setting information 144 and executes link-up processing.

Figure 6 is a diagram for explaining a link-up control method that achieves both firmware update and link-up processing. In the example shown in Figure 6, the firmware of the upper processing unit 121 of OLT 102 is updated. In this case, OLT 101 is determined as the alternative destination for link-up processing by OLT 102. Furthermore, OLT 101 is configured so that it can take over the link-up processing of OLT 102.

Specifically, if a firmware update is scheduled, the upper processing unit 121 copies the setting information 144 of OLT 102 to OLT 101. The setting information 144A stored inside OLT 101 is a copy of the setting information 144, and is transferred to OLT 101 via the link between OLT 101 and OLT 102.

Furthermore, the upper processing unit 121 sends a control signal to the communication processing unit 124 to change the settings of the communication processing unit 124. Similarly, the upper processing unit 121 sends a control signal to the communication processing unit 114 via the communication processing unit 124. As a result, when the communication processing unit 124 receives a link-up signal from an ONU under the OLT 101, the communication processing unit 124 transfers a link-up notification to the communication processing unit 114. The communication processing unit 114 transfers the link-up notification to the upper processing unit 111. When the upper processing unit 111 receives the link-up notification, it transfers a control signal for setting the communication processing unit 124 to the communication processing unit 124 via the communication processing unit 114. For example, the upper processing units 111 and 121 transmit and receive control signals between the communication processing units via their respective control ports (indicated as "Port 1" in FIG. 6), and the communication processing units 114 and 124 transmit and receive control signals to each other via their respective communication ports (indicated as "Port 2" in FIG. 6).

When the upper processing unit 111 receives a firmware update completion notification from the OLT 102, it transfers the latest information on the status of the ONUs managed by the OLT 102 to the OLT 102. Furthermore, the upper processing unit 111 changes the settings of the communication processing unit 124 so that link-up signals from the ONUs under the control of the OLT 102 are not transferred to the OLT 101. As a result, after the firmware of the OLT 102 is updated, the execution of the link-up process is returned from the OLT 101 to the OLT 102.

According to the control method shown in FIG. 6, OLT 101 is determined as an alternative destination for link-up processing for linking up ONUs under OLT 102 by OLT 102, which can communicate with OLT 101 and is scheduled to have its firmware updated. Then, OLT 101 is set so that it can take over the link-up processing of OLT 102. When OLT 102 updates its firmware, after the update, the execution subject of the link-up processing is returned from OLT 101 to OLT 102. This makes it possible to achieve both firmware updates for OLT 102 and link-up processing.

Firmware updates and ONU link-up are independent events. Although an OLT firmware update is definitely scheduled, it may happen that at the start of the firmware update, it is unclear whether link-up processing will be necessary. In this embodiment, even in such a case, the other OLT is determined as the alternative destination for link-up processing, making it possible to handle link-up processing during firmware update. In other words, in this embodiment, when one OLT has a firmware update scheduled, it is sufficient that the other OLT is set to be able to take over link-up processing, and it is not necessarily necessary that both link-up processing and link-up processing be performed during firmware update.

Figure 7 is a sequence diagram explaining the overall flow of the link-up process according to this embodiment. As with Figure 6, Figure 7 shows the flow of the process when the firmware of OLT 102 is updated and OLT 101 takes over the link-up process of OLT 102.

First, an update of the firmware (FW) of the upper processing unit 121 is started (step S11). The upper processing unit 121 refers to its own setting information 144 (step S12). The upper processing unit 121 copies the setting information 144 to the upper processing unit 111 (step S13). As a result, setting information 144A, which is a copy of the setting information 144, is transferred to the upper processing unit 111 via the communication processing unit 124 and the communication processing unit 114.

In this way, the upper processing unit 111 is configured to be able to replace the link-up processing of OLT 102 by receiving settings for link-up processing by OLT 102 from OLT 102.

Next, the upper processing unit 121 changes the link-up notification path for the communication processing unit 124 and the communication processing unit 114 (steps S14 and S15). This changes the path so that the link-up notification from the communication processing unit 124 is forwarded to the communication processing unit 114.

The ONU under the control of OLT 102 transmits a link-up signal (step S16). When the communication processing unit 124 receives the link-up signal from the ONU, it generates a link-up notification based on the link-up signal. The communication processing unit 124 transmits the link-up notification to the communication processing unit 114. The link-up notification is transferred from the communication processing unit 114 to the upper-level processing unit 111 (step S17). This allows the upper-level processing unit 111 to execute link-up processing for linking up the ONU under the control of OLT 102, instead of the upper-level processing unit 121.

The link-up notification includes information identifying the ONU to be linked up and information identifying the OLT to which the link-up signal is to be sent. Although not limited to the items listed below, the link-up notification may include, for example, the OLT's MAC (Media Access Control) address (OLTMAC), port number (Port No), the ONU's MAC address, and the message type (see Figure 10). An example of the information included in the link-up notification is shown below.

OLTMAC＝AA:BB:CC:DD:EE:FF
Port No. = 1
ONUMAC＝00:11:22:33:44:55
Message type: Link up Of the above information, "Port No.=1" means the specification of the control port "Port 1" of the upper processing unit shown in FIG.

While OLT 101 is the alternative destination for link-up processing of OLT 102, the upper processing unit 111 is responsible for processing for linking up ONUs under OLT 102 in addition to linking up ONUs under OLT 101. Therefore, based on the link-up notification transferred from the communication processing unit 114, the upper processing unit 111 determines whether the ONU that is the target of the link-up processing is under the control of OLT 101 or OLT 102.

The upper processing unit 111 refers to the OLTMAC in the link-up notification received from the communication processing unit 124. The OLTMAC corresponds to an identifier for identifying the OLT. Based on the OLTMAC included in the link-up notification, the upper processing unit 111 can determine whether the link-up notification received from the communication processing unit 114 is a notification addressed to OLT 101 or OLT 102.

In the example shown in FIG. 7, the upper processing unit 111 receives a link-up notification addressed to the OLT 102. In this case, the upper processing unit 111 refers to the setting information 144A to obtain information for linking up the ONU under the OLT 102. The upper processing unit 111 performs communication settings for the communication processing unit 124 and the ONU according to that information (steps S19, S20). As a result, the communication processing unit 124 and the ONU that sent the link-up signal are in a state where communication settings can be made by the upper processing unit 111. Therefore, the link-up process for the ONU is performed by the upper processing unit 111.

The firmware update in the upper processing unit 121 is completed (step S21). The upper processing unit 121 sends a control signal to the communication processing unit 124 and the communication processing unit 114 to change the link-up notification path (steps S21, S22). In this case, the link-up notification path is returned so that the link-up notification from the communication processing unit 124 is forwarded from the communication processing unit 124 to the upper processing unit 121. As a result, the execution entity of the process for linking up the ONUs under the OLT 102 is returned from OLT 101 to OLT 102.

Then, the upper processing unit 121 requests the upper processing unit 111 to delete the setting information 144A (step S23). In response to the request, the upper processing unit 111 deletes the setting information 144A (step S24). This ends the series of processes.

The same process is performed when OLT 102 takes over the link-up process of OLT 101. When OLT 102 takes over the link-up process of OLT 101, in the following explanation, "OLT 101" (upper processing unit 111, communication processing unit 114) and "OLT 102" (upper processing unit 121, communication processing unit 124) can be interchanged.

In this embodiment, the link-up process is not limited to a specific process. FIG. 8 is a sequence diagram explaining an example of the link-up process. Note that, although this is not intended to limit this embodiment, FIG. 8 shows, as an example, the link-up process conforming to IEEE 802.3av and ah. The sequence diagram in FIG. 8 also shows, without distinction, both a case in which the upper processing unit (111, 121) of each OLT executes the link-up process for the ONU under that OLT, and a case in which one of two OLTs substitutes for the link-up process of the other.

First, link-up is performed using MPCP (Multi-point Control Protocol), which controls communication between the lower processing units (112, 122) and the ONU (step S31). The OLT establishes a link with a new ONU according to MPCP. Furthermore, link-up is performed between the lower processing units and the ONU using OAM (Operation Administration and Maintenance) (step S32).

Then, the lower processing unit sends a link-up notification to the upper processing unit (step S33). An example of the contents of the link-up notification is shown below.

OLTMAC＝AA:BB:CC:DD:EE:FF
Port No. = 1
ONUMAC＝00:11:22:33:44:55
Message type: Link up When the upper processor receives the link up notification, it refers to the setting information (134, 144 or 144A) (step S34). The setting information 144 includes, for example, the MAC address of the ONU (ONU MAC), the port to which the ONU belongs, the ONU number, the VLAN to which the ONU belongs, and the number of UNI (User Network Interface) ports. However, the information included in the setting information 144 is not limited to these.

The upper processing unit 121 configures the lower processing unit 122 according to the configuration information (step S35). When the OLT communication configuration is complete, the lower processing unit becomes capable of communication.

The upper processing unit then performs communication settings for the ONU (step S36). When the ONU communication settings are complete, the ONU is ready for communication. In the ONU communication settings, proprietary messages are exchanged between the OLT and the ONU. Message conversion in the lower processing unit allows messages to be exchanged between the ONU and the OLT according to OAM, for example, compliant with IEEE 802.3av and ah. Examples of messages exchanged in the ONU communication settings are shown below.

(1) Message before conversion:
OLTMAC＝AA:BB:CC:DD:EE:FF
Port No.＝１
ONUMAC＝00:11:22:33:44:55
Message type: ONU communication settings Subcategory: ONU queue settings (2) Converted message (IEEE 802.3av, ah compliant OAM)
Dest MAC＝01:80:c2:00:00:02
Src MAC＝AA:BB:CC:DD:EE:FF (i.e. OLT MAC)
ethType = OAM
Type = 0xFE (vendor specific)
OUI = 0xXXXXXX
Message type: ONU communication setting Sub-category: ONU route setting FIG. 9 is a diagram for explaining information transmitted via the communication setting unit. Referring to FIG. 9, a link-up signal transmitted from the ONU is input to the PON interface unit 123. When the firmware is not being updated in the upper processing unit 121 (i.e., during normal operation), the communication processing unit 124 transmits a link-up notification to the upper processing unit 121. In this case, the communication processing unit 124 only needs to identify the ONU that transmitted the message from the LLID (Logical Link ID) included in the received message and notify the upper processing unit 121. It is also possible for the communication processing unit 124 to only notify the upper processing unit 121 via the bus that a link process is required.

On the other hand, when the firmware is being updated in the upper processing unit 121, the communication processing unit 124 transfers the link-up notification to the OLT 101 (not shown in FIG. 9). In this case, the communication processing unit 124 may store the link-up notification in a frame and transfer the frame to the OLT 101. It is preferable that the frame that stores the link-up notification is a frame used in, for example, Layer 2 (L2) communication or Layer 3 (L3) communication.

The communication processing unit 124 can determine whether the message that arrived at the communication processing unit 124 is a message for OLT communication setting or a message for ONU communication setting based on the message type. If the message that arrived at the communication processing unit 124 is a message for OLT communication setting, the communication processing unit 124 performs processing based on that message. If the message that arrived at the communication processing unit 124 is a message for ONU communication setting, communication setting is performed using a dedicated frame format addressed to the ONU. In this case, the communication processing unit 124 is responsible for converting the control signal sent by the upper processing unit 121 into a dedicated frame format addressed to the ONU.

Figure 10 shows an example of the format of a frame that the communication processing unit exchanges with the ONU. As shown in Figure 10, the frame includes a destination address (DA) field, a source address (SA) field, a VLAN (Virtual LAN) field, a type field, a data field, and an FCS (Frame Check Sequence) field. Note that the preamble is not shown in Figure 10.

The destination address field and source address field store the MAC address of the destination node and the MAC address of the source node, respectively.

The VLAN field is a field for specifying a tag header for a VLAN tag. For example, if OLT 102 is the sender, the VLAN ID is specified as 10, and if it is an ONU with port number 1 (Port1), the VLAN ID is specified as 1001. In this case, OLT 101 has a correspondence table that associates VLANs with senders.

The type field stores the code 0xFE, which indicates vendor specific. The data field stores various information such as the message type, information for identifying the ONU (LLID, MAC address, link management information), and the ONU status.

The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is indicated by the claims rather than the embodiments described above, and is intended to include all modifications within the scope of the claims and meanings equivalent thereto.

10 PON system 11, 12 Optical line 100 Station side device 101, 102 OLT
111, 121 Upper processing unit 112, 122 Lower processing unit 113, 123 PON interface unit 114, 124 Communication processing unit 115, 125 Upper interface unit 131 Update unit 132 Storage unit 133 Control unit 134, 144, 144A Setting information 211 to 21M, 221 to 22N ONU
S1 to S5, S1A, S2A, S11 to S24, S31 to S36 steps

Claims (8)

A link-up control method for controlling link-up of a home device by a station device having a plurality of OLTs, comprising:
determining a first OLT among the plurality of OLTs as an alternative destination for a link-up process for the link-up of a home appliance under the control of a second OLT, the second OLT being capable of communicating with the first OLT among the plurality of OLTs and having a firmware update scheduled;
setting the first OLT so as to be able to substitute for the link-up process of the second OLT;
updating firmware by the second OLT;
and returning a subject of execution of the link-up process from the first OLT to the second OLT after updating the firmware. The link-up control method according to claim 1, further comprising a step of determining, by the first OLT, whether an optical network device that is the subject of the link-up process is subordinate to the first OLT or the second OLT, while the first OLT is the alternative destination of the link-up process of the second OLT. The step of configuring the first OLT includes:
a step of setting a notification path so as to transfer a link-up notification sent from the home device that is a target of the link-up process to the second OLT to the first OLT;
The link-up control method of claim 2, wherein the determining step includes a step of determining, when the first OLT receives the link-up notification from the second OLT, based on information contained in the link-up notification, that the home device that is to be the target of the link-up processing is a home device under the control of the second OLT. A station side device,
A plurality of OLTs are provided,
A first OLT; and
a second OLT communicatively connected to the first OLT, the second OLT having firmware;
When the second OLT is scheduled to update the firmware, the first OLT is determined as an alternative destination of a link-up process for linking up a home device under the second OLT by the second OLT;
The first OLT is capable of substituting for the link-up process by taking over a setting for the link-up process by the second OLT from the second OLT,
When the second OLT updates the firmware, a subject of execution of the link-up process is returned from the first OLT to the second OLT. Each of the first OLT and the second OLT comprises:
a host processing unit; and a lower processing unit capable of communicating with the host processing unit and responsible for communication with an optical network unit;
The lower processing unit of the first OLT and the lower processing unit of the second OLT are connected to each other so as to be able to communicate with each other;
5. The station side device according to claim 4, wherein when there is a schedule for updating the firmware held by the upper processing unit of the second OLT, the upper processing unit of the first OLT is configured to be able to take over the link-up processing by receiving settings for the link-up processing by the second OLT from the second OLT. The optical line terminal according to claim 5, wherein when the upper processing unit of the first OLT receives a link-up notification from the lower processing unit of the first OLT while the first OLT is the alternative destination of the link-up process of the second OLT, the upper processing unit of the first OLT determines, based on information included in the link-up notification, whether the optical line terminal that is the target of the link-up process is subordinate to the first OLT or the second OLT. The station side device according to claim 5 or claim 6, wherein the lower processing unit of the second OLT sets a transfer path for the link-up notification so that a link-up notification for the link-up of the home device under the control of the second OLT is transferred to the upper processing unit of the first OLT when the first OLT can take over the link-up process. An OLT,
A host processor having firmware;
a lower processing unit capable of communicating with the upper processing unit and other OLTs and responsible for communication with a home device;
When there is a plan to update the firmware of the upper processing unit, the upper processing unit substitutes the link-up processing for linking up the home device with the other OLT through the lower processing unit, and after updating the firmware, returns the execution entity of the link-up processing from the other OLT to the upper processing unit.

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