JP2015088815A - Customer home side device, pon system and control method for customer premise side device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for enabling smooth provision of a multicast service.SOLUTION: A customer home side device (ONU) 2, on receiving multicast data according to the reception condition of a terminal device 5 from a passive optical network (PON line 3), transfers the multicast data to the terminal device 5. A station side device (OLT) 1a manages the transfer state of the ONU 2 capable of executing the multicast data transfer to the terminal device 5. On the occurrence of a redundancy switchover in the OLT 1a, the ONU 2 allows the transfer state of the ONU 2 to match the reception condition of the terminal device 5.

Description

  The present invention relates to a home apparatus, a PON (Passive Optical Network) system, and a home apparatus control method. In particular, the present invention relates to a home-side device connected to a redundant station-side device via an optical line.

  One form for realizing FTTH (Fiber To The Home) is PON (Passive Optical Network). Today, EPON, which is a PON to which Ethernet (registered trademark) technology is applied, is widely used for FTTH services.

  A configuration of a PON system with improved robustness against communication failures has been proposed so far. For example, Non-Patent Document 1 (“IEEE P1904.1 / D3.4 Draft Standard for Service Interoperability in Ethernet Passive Optical Networks (SIEPON)”, April 2013, pp. 238-245) describes a redundant OLT (Optical A PON system having a Line Terminal) is disclosed. When an ONU (Optical Network Unit) receives a transition message instructing transition from the OLT to the holdover state, reception of downlink data continues while suppressing transmission of uplink data.

"IEEE P1904.1 / D3.4 Draft Standard for Service Interoperability in Ethernet Passive Optical Networks (SIEPON)", April 2013, p. 246

  Various methods for distributing multicast data to terminal devices accommodated in each of a plurality of home-side devices have been proposed. For example, such a method can be used in the distribution of video data. However, the above document does not show a configuration or method for continuously enabling multicast data distribution even when redundant switching of OLT occurs. If the distribution of multicast data becomes impossible due to redundancy switching, the multicast service will be degraded.

  An object of the present invention is to provide a technique for realizing smooth provision of a multicast service in a PON system.

  A home-side device according to an aspect of the present invention is a home-side device for communicating with a station-side device via a passive optical network. Upon receiving multicast data corresponding to the reception state of the terminal device from the passive optical network, the home side device is managed based on the reception state of the terminal device in the receiving unit that transfers the multicast data to the terminal device and the station side device. And a control unit that sets the transfer state of the home side device for executing the transfer of the multicast data to the terminal device in the home side device. When the station side device is made redundant, when the redundancy switching occurs in the station side device, the control unit matches the transfer state of the home side device with the reception state of the terminal device.

  A PON system according to another aspect of the present invention includes a station-side device, a home-side device, and a passive optical network that connects the station-side device and the home-side device. The station side device manages the transfer state of the home side device so that the home side device can transfer multicast data to the terminal device based on the reception state of the terminal device accommodated in the home side device. The home device sets the transfer state managed by the station device to the home device. When the station side device is made redundant, when the redundancy switching occurs in the station side device, the home side device matches the transfer state of the home side device with the reception state of the terminal device.

  A home apparatus control method according to still another aspect of the present invention is a home apparatus control method for communicating with a station apparatus via a passive optical network. In the control method, the station side device manages the transfer state of the home side device for executing the transfer of multicast data to the terminal device, which is managed based on the reception state of the terminal device accommodated in the home side device. The step of setting in the home side device, the step of detecting that the redundancy switching is started in the station side device when the station side device is made redundant, and the detection of the completion of the redundancy switching in the station side device And a step of matching the transfer state of the home side device with the reception state of the terminal device by the end of the redundancy switching.

  According to the above aspect of the present invention, smooth provision of a multicast service can be realized in the PON system.

It is a block diagram which shows schematic structure of the PON system which concerns on one Embodiment of this invention. FIG. 2 is a block diagram illustrating a configuration of an ONU illustrated in FIG. 1. It is a sequence diagram for demonstrating one delivery method of the multicast data in a PON system. It is a figure explaining the example of the table which matches with a channel and a group address memorize | stored in OLT. It is the figure explaining the example of the table which matches with the group address and destination MAC address which are memorize | stored in OLT. It is a sequence diagram for demonstrating switching of the optical line unit which has a redundant structure according to one Embodiment of this invention. It is a sequence diagram for demonstrating the process of ONU according to the 1st Embodiment of this invention. It is the figure which showed an example of the structure of the database memorize | stored inside ONU. It is a flowchart explaining the message aggregation processing by ONU. It is a sequence diagram for demonstrating the switching of the optical line unit which has a redundant structure, and the setting of the switching destination optical line unit according to the 2nd Embodiment of this invention. It is a flowchart explaining the process of ONU according to the 2nd Embodiment of this invention. It is a sequence diagram for demonstrating the process of ONU according to the 3rd Embodiment of this invention. It is a flowchart explaining the process of ONU according to the 3rd Embodiment of this invention.

[Description of Embodiment of Present Invention]
First, embodiments of the present invention will be listed and described.

  (1) A home-side device according to an embodiment of the present invention is a home-side device for communicating with a station-side device via a passive optical network. Upon receiving multicast data corresponding to the reception state of the terminal device from the passive optical network, the home side device is managed based on the reception state of the terminal device in the receiving unit that transfers the multicast data to the terminal device and the station side device. And a control unit that sets the transfer state of the home side device for executing the transfer of the multicast data to the terminal device in the home side device. When the station side device is made redundant, when the redundancy switching occurs in the station side device, the control unit matches the transfer state of the home side device with the reception state of the terminal device.

  According to this configuration, even when redundancy switching occurs in the station side device, the home side device can transfer multicast data corresponding to the reception state of the terminal device to the terminal device. Therefore, smooth provision of multicast service can be realized in the PON system.

  The “reception state of the terminal device” may include both a current state in which the terminal device receives the multicast and a state in which the terminal device intends to receive the multicast from now on.

  “The station side device is made redundant” may include both the case where the internal configuration of the station side device is made redundant and the case where a plurality of station side devices are redundantly arranged.

  (2) Preferably, the home side device further includes a transmission unit for transmitting a message sent from the terminal device and indicating a reception state from the terminal device to the station side device via the passive optical network. When a message is transmitted from the terminal device during redundancy switching of the station side device, the control unit collects the message. After the redundancy switching of the station side device, the transmission unit transmits the message aggregated by the control unit.

  According to this configuration, the home side device can inform the station side device of the accurate reception state of the terminal device. A configuration is conceivable in which the home side device stores the message from the terminal device in the buffer memory during the redundant switching of the station side device. However, for example, when the capacity of the buffer memory is small and the number of messages is large, there is a possibility that the home-side device misses (loses) the message from the terminal device. By collecting the messages from the terminal devices, the storage capacity required for the home device to hold the messages can be reduced. Therefore, the probability that the home device will miss the message from the terminal device is reduced. As a result, the home side device can inform the station side device of the accurate reception state of the terminal device.

  (3) Preferably, the home side device is provided in any of the home side devices, stores information regarding the reception state of the terminal device, and updates information according to a message from the terminal device Is further provided. The control unit aggregates the plurality of messages based on information stored in the storage unit.

  According to this configuration, the storage capacity required for the home device to hold the message can be reduced. Note that the “storage unit” may be provided in the home device. Therefore, the storage unit may be integrated with the control unit, or may be provided independently of the control unit.

  (4) Preferably, after the redundancy switching of the station side device, the control unit inquires the reception state of the terminal device, and instructs from the station side device after the redundancy switching based on the answer about the reception state from the terminal device. Set the transfer status according to.

  According to this configuration, after the redundancy switching in the station side device, the transfer state of the home side device can be matched with the reception state of the terminal device in a shorter time. As a result, a high-quality multicast service can be provided.

  (5) A PON system according to an embodiment of the present invention includes a station-side device, a home-side device, and a passive optical network that connects the station-side device and the home-side device. The station side device manages the transfer state of the home side device so that the home side device can transfer multicast data to the terminal device based on the reception state of the terminal device accommodated in the home side device. The home device sets the transfer state managed by the station device to the home device. When the station side device is made redundant, when the redundancy switching occurs in the station side device, the home side device matches the transfer state of the home side device with the reception state of the terminal device.

  According to this configuration, even when redundancy switching occurs in the station side device, the home side device can transfer multicast data corresponding to the reception state of the terminal device to the terminal device. Therefore, smooth provision of multicast service can be realized in the PON system.

  (6) The home apparatus control method according to the embodiment of the present invention is a home apparatus control method for communicating with a station apparatus via a passive optical network. In the control method, the station side device manages the transfer state of the home side device for executing the transfer of multicast data to the terminal device, which is managed based on the reception state of the terminal device accommodated in the home side device. The step of setting in the home side device, the step of detecting that the redundancy switching is started in the station side device when the station side device is made redundant, and the detection of the completion of the redundancy switching in the station side device And a step of matching the transfer state of the home side device with the reception state of the terminal device by the end of the redundancy switching.

  According to this configuration, smooth provision of a multicast service can be realized in the PON system.

[Details of the embodiment of the present invention]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and detailed description thereof will not be repeated.

  FIG. 1 is a block diagram showing a schematic configuration of a PON system according to an embodiment of the present invention. Referring to FIG. 1, the PON system 301 is realized as an EPON. EPON applicable to this embodiment is, for example, GE-PON, 10GE-PON, or the like.

  The PON system 301 includes a station side device (OLT) 1a, N PON lines 1 to N (3-1 to 3-N), which are optical fibers, and N optical couplers 4-1 to 4-N. A plurality of home-side devices (ONU) 2 and a terminal device 5 connected to the ONU 2 are provided. N is an integer of 1 or more (the same applies to the following).

  The OLT 1a is connected to N PON lines 1 to N and terminates the N PON lines. PON lines (passive optical networks) 1 to N are connected to optical couplers 4-1 to 4 -N, respectively. Each PON line is connected to a plurality of ONUs 2 via corresponding optical couplers and optical lines 31.

  Each ONU 2 is connected to at least one terminal device 5 via the home network 32. That is, each ONU 2 accommodates the terminal device 5. For example, a plurality of terminal devices 5 can be connected to one ONU 2 via a hub (HUB).

  The plurality of ONUs 2 include at least one ONU 2 to which a terminal device 5 capable of viewing video is connected. The terminal device 5 can select (switch) the viewing channel. The type of such terminal device 5 is not particularly limited.

  The OLT 1a is connected to the upper network 6. The upper network 6 includes a router 7 and a video distribution server 8. The OLT 1a distributes the video data from the video distribution server 8 to at least one terminal device 5 that requests viewing of the video using multicast communication. The video data is distributed to the terminal device 5 as multicast data.

  When receiving the multicast data from the video distribution server 8, the router 7 transmits the multicast data to the OLT 1a. The router 7 may copy the multicast data as necessary.

  The OLT 1a transmits multicast data from the upper network 6 to the PON lines 3-1 to 3-N. The optical coupler provided in each PON line divides the downstream optical signal from the OLT 1a. Therefore, in the optical coupler, a plurality of copies of the multicast data are created, and each of the plurality of multicast data is sent to the corresponding ONU port. The processing of multicast data in each ONU 2 will be described in detail later.

  Next, the configuration of the OLT 1a will be described. The OLT 1a includes an optical switch 11a, optical line units (OSU) 1 to N + 1 (12-1 to 12-N + 1), a concentrator 13a, and a controller 14.

  The OLT 1a has an N: 1 redundant configuration. That is, out of N + 1 OSUs 12, OSU1 to N are active (active) OSUs, and OSU N + 1 is a standby (standby) OSU. Each of OSU1 to N terminates the corresponding PON line. The OSU N + 1 is configured to be able to replace each of the OSUs 1 to N. For example, OSU1 to N + 1 have the same configuration. The OLT 1a may include two or more standby OSUs.

  The optical switch 11a is connected between the N + 1 OSU1 to N + 1 (12-1 to 12-N + 1) and the N PON lines 1 to N (3-1 to 3-N) according to an instruction from the control unit 14. Switch the communication path. The optical switch 11a performs switching from the active OSU to the standby OSU so that the OSU N + 1 terminates the PON line (for example, PON line 1) where a certain active OSU (for example, OSU 1) has terminated. . The optical switch 11a may further perform switching from the standby OSU to the active OSU. Various known optical switches can be applied to the optical switch 11a.

  For example, the concentrator 13a distributes the multicast data received from the upper network to an appropriate OSU. The control unit 14 controls the entire OLT 1a.

  FIG. 2 is a block diagram showing the configuration of the ONU 2 shown in FIG. Referring to FIG. 2, ONU 2 includes a control unit 21, a transmission unit 22, a reception unit 23, and a storage unit 24.

  The transmission unit 22 performs uplink communication. For example, the transmission unit 22 receives a frame from the terminal device 5 through the home network 32. This frame may include a control frame and a data frame. Note that the control frame is not limited to a specific type of frame. The transmission unit 22 converts the received frame into an optical signal and transmits the optical signal to the optical line 31.

  The receiving unit 23 performs downlink communication. The receiving unit 23 receives an optical signal transmitted through the optical line 31. Furthermore, the receiving unit 23 converts the optical signal into a frame in the form of an electrical signal. The receiving unit 23 reads the header portion of the frame. When the LLID (Logical Link ID) included in the frame matches the LLID of the ONU 2 or the broadcast LLID, the receiving unit 23 receives the frame. Otherwise, the receiving unit 23 discards the frame.

The receiving unit 23 transmits the received frame to the home network 32.
The storage unit 24 stores various types of information necessary for controlling the ONU 2 by the control unit 21. For example, the storage unit 24 stores information related to the current reception state of the terminal device 5. In the configuration shown in FIG. 2, the storage unit 24 is provided independently of the control unit 21. However, the storage unit 24 may be included in the control unit 21. Therefore, the memory | storage part 24 should just be provided in either the inside of the home side apparatus 2. FIG.

  The control unit 21 receives the control frame transmitted from the OLT 1a and executes processing corresponding to the frame. Further, the control unit 21 controls the transmission unit 22 and the reception unit 23.

  FIG. 3 is a sequence diagram for explaining one method of distributing multicast data in the PON system. Referring to FIGS. 2 and 3, the content of a certain viewing channel is transmitted in the form of multicast data from upper network 6 (video distribution server 8 and router 7) to OLT 1a. The OLT 1a assigns a broadcast LLID (Logical Link ID) to the multicast data and transfers the multicast data to the PON line. Since the broadcast LLID is attached to the multicast data, the multicast data is sent to all ONUs 2 (S101).

  When the terminal device 5 under the ONU 2 is not viewing the channel, the MAC (Media Access Control) address filter of the ONU 2 is set not to pass the multicast data. The multicast data is discarded at the receiving end of the ONU 2.

  The viewing channel is set to “X” in the terminal device 5. Thereby, the reception state of the terminal device 5 is set to a state of receiving the multicast data of the channel X. The terminal device 5 transmits a message (frame) indicating the reception state of the channel X to the ONU 2. This message is a message called “Join”, for example. As a message transmission protocol, for example, Internet Group Management Protocol (IGMP) can be used for IPv4 (Internet Protocol version 4), and Multicast Listener Discovery (MLD) can be used for IPv6 (Internet Protocol version 6). Can do.

  When the ONU 2 receives a message from the terminal device 5, it gives its own LLID to the message. The ONU 2 transfers the message with the LLID assigned to the OLT 1a (S102). This message includes information indicating the reception state of the terminal device 5. For example, the message may include channel information viewed on the terminal device 5. Further, the message from the terminal device 5 may include group address information to be described later.

  In the OLT 1a, a message from the terminal device 5 is sent to the optical line unit that terminates the PON line connected to the ONU 2. The optical line unit stores a table that associates channels with group addresses. Further, the optical line unit stores a group address and a MAC address in association with each ONU 2.

  FIG. 4 is a diagram illustrating an example of a table that associates channels and group addresses and is stored in the OLT 1a. Referring to FIG. 4, channels (CHX, CHY,...) And group addresses (GX, GY,...) Are uniquely associated. CHX, CHY,... Represent channels X, Y,.

  FIG. 5 is a diagram illustrating an example of a table that associates a group address with a destination MAC address, which is stored in the OLT 1a. Referring to FIG. 7, # 1 and # 2 are identifiers of ONU 2, for example, LLID. However, the LLID itself is not limited to being used as an identifier, and # 1 and # 2 may be identifiers associated with the LLID. Using this identifier as a key, the multicast group address (GX, GY,...) And the destination MAC address associated with the group address are managed by the OLT 1a (optical line unit).

  Returning to FIG. 3, in the OLT 1a, the optical line unit reads the viewing channel information and the LLID included in the message. The optical line unit sets a MAC address filter for the ONU 2 specified by the LLID. Specifically, the optical line unit notifies the ONU 2 so that the multicast data of the viewing channel indicated by the message passes. For this notification, for example, an extended OAM (Operation, Administration, and Maintenance) frame can be used (S103).

  The ONU 2 receives the notification (for example, the extended OAM frame) from the OLT 1a (optical line unit), and sets the filtering function so as to pass the multicast data to which the destination MAC address specified by the notification is passed. After setting the filtering function, the ONU 2 notifies the OLT 1a that the setting of the filtering function is completed (S104).

  In this way, the OLT 1a manages the transfer state of the ONU 2 by receiving a message including information regarding the reception state of the terminal device 5. The “ONU transfer state” means an ONU state in which multicast data can be transferred to the terminal device 5.

  Thereafter, when the OLT 1a receives the multicast data from the upper network 6, the OLT 1a adds the broadcast LLID to the multicast data and transmits the multicast data to each ONU 2. If the multicast data is data associated with the destination MAC address preset in the ONU 2, each ONU 2 transfers the multicast data to the terminal device 5 by the filtering function (S105). Therefore, the terminal device 5 can view the content of the channel X. That is, multicast data corresponding to the reception state of the terminal device 5 is sent to the terminal device 5.

  FIG. 6 is a sequence diagram for illustrating redundant switching of OLT according to an embodiment of the present invention. Referring to FIG. 6, first, the switching destination optical line unit (optical line unit (1)) performs network operation of the PON line including multicast processing. The optical line unit (1) indicates a first optical line unit, and is, for example, an operational OSU.

  For example, as in the sequence shown in FIG. 3, a message from the terminal device 5 is sent to the optical line unit (1) (S102). The optical line unit (1) sets an ONU MAC address filter (S103). Thereby, the multicast data of channel X is sent to the terminal device 5 through the ONU 2 (S105).

  In step S1, the optical line unit (1) stops the multicast control process. In step S2, the optical line unit (1) transmits information such as the final state and setting parameters regarding multicast control to the optical line unit (2). For example, information regarding the multicast state of the optical line unit (1) is transmitted to the optical line unit (2). The optical line unit (2) indicates a second optical line unit, and is, for example, a standby OSU.

  In step S3, the optical line unit (2) prepares for switching. In step S4, the optical switch 11a (see FIG. 1) switches the optical line unit that should terminate the PON line from the optical line unit (1) to the optical line unit (2).

  The optical line unit (2) starts operating the PON line. Thereafter, the optical line unit (2) executes the same process as the multicast control process by the optical line unit (1).

  For example, after the process of step S2, the terminal device 5 changes the viewing channel from X to Y. A Leave message indicating the stop of viewing of the channel X is transmitted from the terminal device 5 to the OLT 1a via the ONU 2 (S5). Next, a Join message indicating viewing of channel Y is transmitted to OLT 1a (S6).

  In this case, since switching from the optical line unit (1) to the optical line unit (2) has not been completed, the optical line unit (1) receives the Leave message and the Join message. However, the optical line unit (1) has already stopped the multicast control process. Therefore, the optical line unit (1) does not process the Leave message and Join message.

  The optical line unit (2) takes over the reception state of the terminal device 5 before the terminal device 5 switches the channel from the optical line unit (1). For this reason, the optical line unit (2) recognizes that the terminal device 5 has selected the channel X. Therefore, the optical line unit (2) does not change the setting of the MAC address filter for the ONU 2. However, the reception state of the terminal device 5 recognized by the optical line unit (2) is different from the actual reception state of the terminal device 5. For this reason, the multicast data corresponding to the reception state of the terminal device 5, that is, the multicast data of channel Y is blocked by the ONU 2 (S7).

  According to the embodiment of the present invention, transmission of multicast data can be continued before and after redundant switching of the OLT 1a. Hereinafter, specific embodiments will be described. It is assumed that the processes in steps S101 to S105 shown in FIG. 3 are performed before the redundant switching in OLT 1a is performed. Therefore, hereinafter, the description of the operation of the PON system before the redundant switching in the OLT 1a is performed will not be repeated.

<First Embodiment>
FIG. 7 is a sequence diagram for explaining ONU processing according to the first embodiment. Referring to FIG. 7, in OLT 1a, switching from optical line unit (1) to optical line unit (2) is executed (steps S1 to S4). During this time, in the terminal device 5, the viewing channel is changed from X to Y, and then the viewing channel is changed from Y to Z. Note that, during the redundant switching in the OLT 1a, in the terminal device 5, the viewing channel may be changed from X to Y and then the viewing channel may be returned from Y to X.

  When the viewing channel is changed from X to Y, the terminal device 5 continuously outputs a Leave message indicating the stop of viewing of the channel X and a Join message indicating viewing of the channel Y. Next, when the viewing channel is changed from Y to Z, the terminal device 5 continuously outputs the Leave message indicating the viewing stop of the channel Y and the Join message indicating the viewing of the channel Z.

  The ONU 2 sequentially receives the above four messages and aggregates these messages. After switching the optical line unit in the OLT 1a, the ONU 2 transmits the aggregated message to the OLT 1a (S11). Specifically, the ONU 2 outputs a Leave message indicating the stop of viewing of the channel X and a Join message indicating viewing of the channel Z.

  The optical line unit (2) receives the message from the ONU 2 and sets the MAC address filter of the ONU 2 (S12). The ONU 2 notifies the OLT 1a that the setting of the filtering function has been completed (S13). By setting the filtering function, the ONU 2 (control unit 21) matches the transfer state of the ONU 2 with the reception state of the terminal device 5.

  The multicast data of channel Z is distributed from the OLT 1a. The ONU 2 passes the multicast data and transfers the multicast data to the terminal device 5 (S14).

  In the ONU 2, the storage unit 24 (see FIG. 2) stores information regarding the reception state of the terminal device 5. The control unit 21 (see FIG. 2) executes the above-described message aggregation processing based on this information. Therefore, the ONU 2 does not need to store all messages from the terminal device 5. Information regarding the reception state of the terminal device 5 is stored in the storage unit 24 in the form of a database, for example.

  FIG. 8 is a diagram showing an example of the configuration of a database stored in the ONU 2. Referring to FIG. 8, for each terminal device 5 under ONU 2, each channel (CHX, CHY,...) And a flag (“Join” or “Leave”) indicating whether Join or Receive has been received. ]). CHX, CHY,..., CHZ represent channels X, Y,. A “Join” flag is set for a channel that has received a Join. A “Leave” flag is set in the channel that has received the Leave. That is, the combined contents of Join and Leave notified by the terminal device 5 are represented by the flags “Join” and “Leave”.

  In the example of the sequence shown in FIG. 7, channel X is currently being viewed at the start of redundant switching (at the start of aggregation). At this time, the table is empty (see FIG. 8A). Next, channel X is switched to channel Y. In this case, channel X (CHX) is registered with a “Leave” flag (see FIG. 8B). Subsequently, channel Y (CHY) is registered with the flag “Join” (see FIG. 8C). Further, channel Y is switched to channel Z. In this case, channel Y (CHY) is deleted from the table (see FIG. 8D). Next, channel Z (CHZ) is registered with the flag “Join” (see FIG. 8E). As a result, the channel X (CHX) is registered with the “Leave” flag and the channel Z (CHZ) is registered with the flag “Join” in the table (see FIG. 8F).

  The control unit 21 (see FIG. 2) searches the registered channel from the database after switching the optical line unit in the OLT 1a. Channel X is registered with flag “Leave”, and channel Z (CHZ) is registered with flag “Join”. The control unit 21 transmits a message (“Leave”) indicating the reception state of the channel X and a message (“Join”) indicating the reception state of the channel Z to the OLT 1a. Therefore, messages are aggregated.

  FIG. 9 is a flowchart for explaining message aggregation processing by the ONU. Referring to FIGS. 2 and 9, when the process is started, control unit 21 determines whether or not redundant switching (switching of the optical line unit) in OLT 1a has been started (step S10A).

  The method for determining that the redundancy switching has been started is not particularly limited. For example, if the PON system 301 conforms to the SIEPON package B, the ONU 2 receives a message instructing the transition from the OLT 1a to the holdover state, and determines (detects) that redundancy switching has started. can do.

  According to another method, the ONU 2 may detect the start of redundant switching by detecting the loss of the optical effective signal from the OLT 1a. Alternatively, the ONU 2 may determine (detect) that redundancy switching has started when the time during which the Gate frame from the OLT 1a is not received exceeds a certain threshold.

  If it is determined that redundant switching of OLT 1a has not been started (NO in step S10A), the process shown in FIG. 9 ends. On the other hand, when it is determined that redundant switching of the OLT 1a has been started (YES in step S10A), the ONU 2 (control unit 21) collects messages from the terminal device 5 (step S10). When a message is transmitted from the terminal device 5 a plurality of times, the control unit 21 updates the database stored in the storage unit 24 in response to the message. When a message is transmitted from the terminal device 5, the database is updated. Therefore, the aggregation process in step S10 is not limited to the case where the message is transmitted from the terminal device 5 a plurality of times, and includes the case where the message is transmitted from the terminal device 5 only once.

  Next, the control unit 21 determines whether or not the redundant switching (switching of the optical line unit) of the OLT 1a has been completed (step S10B). The method for determining that the switching of the optical line unit is started is not particularly limited. For example, if the PON system 301 conforms to the SIEPON package B as described above, the ONU 2 has received the message instructing the end of the holdover state from the OLT 1a, and the redundancy switching has been completed. May be determined (detected). Alternatively, the ONU 2 may determine (detect) that the switching has ended by receiving the Gate frame from the OLT 1a again.

  If it is determined that redundancy switching has not ended (NO in step S10B), the process returns to step S10. That is, the ONU 2 collects messages from the terminal device 5 until the redundancy switching is completed. On the other hand, if it is determined that the redundancy switching has ended (YES in step S10B), the ONU 2 (control unit 21) transmits the aggregated message to the OLT 1a (step S11).

When the process of step S11 ends, the entire process illustrated in FIG. 7 ends.
As described above, in the first embodiment, the ONU 2 executes a part of the function of the OLT 1a (part of the function of the MLD proxy) after the redundant switching of the OLT 1a (switching of the optical line unit). Specifically, the ONU 2 matches the transfer state of the ONU 2 and the reception state of the terminal device 5 by transmitting the aggregated message to the OLT 1a.

  Due to redundant switching of the OLT 1a, a mismatch may occur between the multicast state of the OLT 1a, the transfer state of the ONU 2 (setting of the MAC address filter), and the reception state of the terminal device 5. At the timing of redundant switching of the OLT 1a, the ONU 2 matches the transfer state of the ONU 2 with the reception state of the terminal device 5. Specifically, the ONU 2 collects and transmits messages from the terminal device 5. As a result, the accurate reception state of the terminal device 5 can be transmitted to the switching destination optical line unit.

  Since the multicast state of the OLT 1a, the transfer state of the ONU 2, and the terminal device 5 can be matched, smooth provision of the multicast service can be realized. For example, when the user switches channels on the terminal device 5 side, the content of the channel after switching can be reproduced on the terminal device 5.

  Further, according to the first embodiment, when a plurality of messages are transmitted from the terminal device 5 during the redundant switching of the OLT 1a, the ONU 2 (the control unit 21) collects the messages. As another method, the ONU 2 may store a plurality of messages sent from the terminal device 5 in a buffer memory. However, for example, when the capacity of the buffer memory is small and the number of messages is large, there is a possibility that the message from the terminal device 5 may be missed in the ONU 2. According to this embodiment, the ONU 2 once aggregates messages from the terminal device 5. Specifically, the database in the storage unit 24 is updated. Thereby, it is possible to prevent the message from being missed. As a result, the correct reception state of the terminal device 5 can be transmitted to the switching destination optical line unit.

  Further, in order to implement all functions of the MLD proxy in the ONU 2, for example, a timer for detecting a timeout is required. However, according to this embodiment, it is possible to select a necessary function from the functions of the MLD proxy and implement it in the ONU 2. As a result, it is possible to suppress an increase in the scale of software or circuits mounted on the ONU 2. Therefore, for example, an increase in the cost of the ONU 2 can be suppressed.

  In the above process, the aggregation of messages from the terminal device 5 is started when the start of switching of the optical line unit is detected. However, message aggregation may be started before the start of switching of the optical line unit is detected.

<Embodiment 2>
FIG. 10 is a sequence diagram for explaining switching of an optical line unit having a redundant configuration and setting of a switching destination optical line unit according to the second embodiment. Referring to FIG. 10, in the second embodiment, after the optical line unit is switched in OLT 1a, ONU 2 transmits an inquiry message to terminal device 5 (step S21). For the inquiry message sent from the ONU 2 to the terminal device 5, for example, General Query, which is an inquiry message of MLDv2, can be used.

  The terminal device 5 transmits a report indicating the current reception state (viewing channel) in response to the inquiry message from the ONU 2. The ONU 2 transfers this report to the OLT 1a (step S22). The OLT (optical line unit (2)) after redundancy switching transmits an extended OAM frame for setting a MAC address filter to the ONU 2 based on a report from the terminal device 5.

  The ONU 2 sets a MAC address filter according to the extended OAM frame transmitted from the OLT 1a (step S23). As a result, the transfer state of the ONU 2 matches the reception state of the terminal device 5. Thereafter, the ONU 2 transfers the data to the terminal device 5 through the multicast data of channel Y (S24).

  FIG. 11 is a flowchart illustrating processing by the ONU according to the second embodiment of the present invention. 2 and 11, when the process is started, control unit 21 of ONU 2 determines whether or not redundant switching in OLT 1a is started (step S10A). If it is determined that redundancy switching has been started (NO in step S10A), the processing shown in FIG. 11 ends.

  If it is determined that redundant switching has started (YES in step S10A), then ONU 2 (control unit 21) determines whether redundant switching of OLT 1a has ended (step S10B). As a method for determining the start and end of redundant switching, the same method as that described in the first embodiment can be used.

  If it is determined that the redundancy switching in OLT 1a has been completed (YES in step S10B), the process proceeds to step S21. On the other hand, when it is determined that the redundancy switching has not ended (NO in step S10B), the process of step S10B is repeated. That is, the process of step S10B is repeated until the redundant switching at OLT 1a is completed.

  In step S <b> 21, the ONU 2 transmits an inquiry message to the terminal device 5. Next, in step S <b> 22, the ONU 2 receives a report from the terminal device 5. However, the ONU 2 simply transfers this report to the OLT 1a. Based on this report, the OLT 1a transmits an (extended) OAM frame for changing the transfer state of the ONU 2 to the ONU 2. The ONU 2 receives this OAM frame. Subsequently, in step S23, the ONU 2 sets a MAC address filter based on the OAM frame received from the OLT 1a. When the process of step S23 ends, the entire process ends.

  According to the second embodiment, the ONU 2 inquires of the terminal device 5 about the reception state. The ONU 2 receives the (extended) OAM frame from the OLT 1a based on the report from the terminal device 5, and sets the MAC address filter based on the (extended) OAM frame. Therefore, after the redundancy switching in the OLT 1a, the ONU 2 MAC address filter can be quickly set. The terminal device 5 can shorten the time (time lag) from when the channel is switched to when the video of the channel after switching can be viewed. As a result, a high-quality multicast service can be provided.

  In addition, when a channel is switched in the terminal device 5 during the redundant switching in the OLT 1a, a message may be transmitted from the terminal device 5. The ONU 2 may discard the message or send it to the OLT 1a.

<Embodiment 3>
In the third embodiment, when redundant switching occurs in the OLT, not only the messages from the terminal device are aggregated but also an inquiry to the terminal device is executed. That is, the third embodiment is a combination of the first embodiment and the second embodiment.

  FIG. 12 is a sequence diagram for explaining ONU processing according to the third embodiment. FIG. 13 is a flowchart illustrating ONU processing according to the third embodiment.

  12 and 13, terminal apparatus 5 sequentially switches the viewing channel from channel X to channel Y and channel Z as in the first embodiment. The ONU 2 sequentially receives the four messages from the terminal device 5 and aggregates these messages (S10). After the redundancy switching (switching of the optical line unit) in the OLT 1a, the ONU 2 transmits the aggregated message to the OLT 1a (S11). The OLT 1a sets a MAC address filter for the ONU 2 (S12).

  Further, the ONU 2 transmits an inquiry message to the terminal device 5 (step S21). The terminal device 5 transmits a report indicating the current reception state in response to the inquiry message from the ONU 2. The ONU 2 transfers this report to the OLT 1a (step S22). The OLT 1a sets a MAC address filter in the ONU 2 based on this report (step S23).

  Since the processing of other steps is the same as the processing described in the first embodiment or the second embodiment, the following description will not be repeated.

  According to Embodiment 3, the MAC address filter of ONU 2 can be set more accurately.

  In the processes shown in FIGS. 12 and 13, the order of the process of step S11 and the process of step S21 may be reversed. However, as described above, in step S22, the ONU 2 transfers the inquiry message from the terminal device 5 to the OLT 1a without processing it.

  Further, in the embodiment of the present invention, the form in which the inside of one OLT is made redundant is shown as one form of making the OLT redundant. However, the OLT may be made redundant by using a plurality of OLTs (for example, two OLTs). The present invention can also be applied to such a configuration.

<Appendix>
In addition to the forms listed in (1) to (6), the embodiment of the present invention can also include the following forms.

(Appendix 1)
The control method for the home side device described in (6) above includes a step (S10) of collecting the messages indicating the reception state of the terminal device during the redundancy switching of the station side device, A step (S11) of transmitting the aggregated message after the redundant switching of the devices.

(Appendix 2)
In the step of aggregating (S10), the home side device collects the messages based on the information related to the reception state of the terminal device stored in the storage unit provided in the home side device.

(Appendix 3)
The method for controlling the home side device described in (6), Supplementary Note 1 or Supplementary Note 2 includes the step (S21) of inquiring the reception state of the terminal device after the redundant switching of the station side device, A step (S23) of setting a transfer state in response to an instruction (OAM frame) from the station side device based on the answer about the state (S22).

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1a Station side device (OLT), 2 Home side device (ONU), 3-1 to 3-N PON line, 4-1 to 4-N optical coupler, 5 terminal device, 6 host network, 7 router, 8 video distribution Server, 11a optical switch, 12-1 to 12-N + 1 optical line unit (OSU), 13a concentrator, 14 controller (OLT), 21 controller (ONU), 22 transmitter, 23 receiver, 24 storage, 31 optical line, 32 home network, 301 PON system, S1 to S4, S10, S10A, S10B, S11, S21 to S23, S101 to S105 steps, X, Y, Z channels.

Claims (6)

A home-side device for communicating with a station-side device via a passive optical network,
When receiving multicast data from the passive optical network according to the reception state of the terminal device, a receiving unit that transfers the multicast data to the terminal device;
The transfer state of the home side device, which is managed based on the reception state of the terminal device in the station side device and can execute transfer of the multicast data to the terminal device, is set in the home side device And a control unit that
When the station side device is made redundant, when the redundancy switching occurs in the station side device, the control unit matches the transfer state of the home side device with the reception state of the terminal device. Side device. The home device is
A transmission unit for transmitting a message sent from the terminal device and indicating the reception state from the terminal device to the station side device via the passive optical network;
When the message is transmitted from the terminal device during the redundancy switching of the station side device, the control unit aggregates the message,
The home apparatus according to claim 1, wherein after the redundancy switching of the station side apparatus, the transmission unit transmits the message aggregated by the control unit. The home device is
A storage unit that is provided in any one of the home-side devices, stores information on the reception state of the terminal device, and updates the information according to the message from the terminal device;
The home apparatus according to claim 2, wherein the control unit aggregates the plurality of messages based on the information stored in the storage unit.   The controller, after the redundancy switching of the station side device, inquires the reception state of the terminal device, and based on the answer about the reception state from the terminal device, the station side after the redundancy switching The home apparatus according to any one of claims 1 to 3, wherein the transfer state is set according to an instruction from the apparatus. A station side device,
A home device,
A passive optical network that connects the station side device and the home side device;
The station side device determines a transfer state of the home side device for enabling the home side device to transfer the multicast data to the terminal device based on a reception state of the terminal device accommodated in the home side device. Manage,
The home side device sets the transfer state managed by the station side device to the home side device,
When the station side device is made redundant, when redundancy switching occurs in the station side device, the home side device matches the transfer state of the home side device with the reception state of the terminal device, PON system. A method for controlling a home device for communicating with a station device via a passive optical network,
In the station side device, the transfer state of the home side device for executing the transfer of the multicast data to the terminal device, which is managed based on the reception state of the terminal device accommodated in the home side device, Setting in the home device;
When the station side device is made redundant, detecting that redundancy switching has been started in the station side device;
Detecting the redundancy switching in the station side device; and
Adjusting the transfer state of the home side device to the reception state of the terminal device upon completion of the redundancy switching.

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