JP5853823B2 - Network control method - Google Patents

Description

  The present invention relates to a network control method including an integrated control unit, a host switch, a station-side device, and a plurality of branches.

  A communication network that connects a building (station) owned by a communication carrier and a subscriber's home is called an access network. In response to the recent increase in communication capacity, optical access networks that enable transmission of an enormous amount of information by using optical communication are becoming mainstream in access networks.

  As one form of the optical access network, there is a passive optical network (PON: Passive Optical Network). The PON includes one station side device (OLT: Optical Line Terminal) provided in the station, a subscriber side device (ONU: Optical Network Unit) provided in each of a plurality of subscriber homes, and an optical splitter. Is done. The OLT and the ONU and the optical splitter are connected by an optical fiber.

  A single-core optical fiber is used for connection between the OLT and the optical splitter. This single-core optical fiber is shared by a plurality of ONUs. The optical splitter is an inexpensive passive element. Thus, PON is excellent in economic efficiency and easy to maintain. For this reason, the introduction of PON is progressing rapidly.

  In PON, signals transmitted from each ONU to the OLT (hereinafter also referred to as upstream optical signals) are combined by an optical splitter and transmitted to the OLT. On the other hand, a signal sent from the OLT to each ONU (hereinafter also referred to as a downstream optical signal) is demultiplexed by the optical splitter and transmitted to each ONU. In order to prevent interference between the upstream optical signal and downstream optical signal, different wavelengths are assigned to the upstream optical signal and downstream optical signal, respectively.

  In PON, various multiplexing techniques are used. The multiplexing technology used in the PON includes time division multiplexing (TDM) technology in which a short interval on the time axis is assigned to each subscriber, wavelength division multiplexing (WDM) in which different wavelengths are assigned to each subscriber (WDM: Wave Division Division Multiplex). And code division multiplexing (CDM) technology that assigns different codes to each subscriber. Among these multiplexing techniques, TDM-PON using TDM is currently most widely used.

  In TDM-PON, TDMA (Time Division Multiple Access) is used. TDMA is a technique in which the OLT manages the transmission timing of each ONU so that upstream optical signals from different ONUs do not collide with each other.

  Normally, in a PON system, one OLT manages one branched PON branch (hereinafter also simply referred to as a branch) including an ONU connected to a branched optical transmission line and a branch destination of the optical transmission line. Yes. Here, for example, when the number of ONUs included in one PON branch is small, the OLT is shared by a small number of ONUs, which is expensive. Therefore, when there are few ONUs in a branch, it is desirable that one OLT manages a plurality of branches. On the other hand, when the load is concentrated on a specific OLT, it is desirable that a plurality of OLTs manage one branch.

  Therefore, a PON system (hereinafter also referred to as TDM / WDM-PON) that enables communication of a plurality of branches by one OLT by using TDM and WDM together has been proposed.

  In TDM / WDM-PON, the OLT can send a downstream optical signal to different branches by changing the transmission wavelength of the downstream optical signal. The ONU can send an upstream optical signal to a specific OLT by sending an upstream optical signal having a wavelength designated by the OLT. As a result, one OLT can communicate with an arbitrary branch constituting the TDM / WDM-PON.

  The OLT used for TDM / WDM-PON includes a plurality of light sources in order to change the transmission wavelength of the downstream optical signal, and there is a technique for switching between an optical switch and an electrical switch each time the transmission wavelength is changed (for example, Patent Document 1).

JP 2011-135280 A

  Here, in the configuration of the conventional example described above, the PON link is disconnected when the OLT is switched. That is, a discovery sequence for establishing a PON link is executed between the new OLT and the ONU. For this reason, when switching the OLT, there is a period in which communication is interrupted, leading to a decrease in communication efficiency.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a network control method that enables switching of station side devices without interrupting communication.

  In order to achieve the above-described object, a first control method of the present invention includes a plurality of station-side devices, a host switch that distributes downlink data signals received from a host network to a plurality of station-side devices according to a routing table, One or a plurality of branches each including a branched optical transmission line and a subscriber side apparatus connected to a branch destination of the optical transmission line, a first group connected to the station side apparatus, and an optical transmission line The optical communication of the other group which has a plurality of optical communication ports divided into the second group to be connected, and the optical signal input to the optical communication port of one group is determined according to the wavelength of the optical signal A network control method including an optical routing unit that outputs from a port and an integrated control unit that manages link information, and performs the following processing.

First, the integrated control unit sends a suspension notice to the switching source station side device. Next, the integrated control unit rewrites the routing table and sends a downlink data signal addressed to the switching target subscriber side device to the switching destination station side device. Next, the integrated control unit notifies link information to the switching-destination station-side device, and instructs the connection with the switching-target subscriber-side device. Next, the switching-source station side device notifies the integrated control unit of a transmission completion notification indicating that there is no downlink data signal addressed to the switching target subscriber-side device in the buffer of the station-side device. Next, the integrated control unit instructs the switching destination station side device to start transmission to the switching target subscriber side device.
Further, after the integrated control section sends the suspension notice to the switching source station side device, the switching source station side device instructs the switching target subscriber side device to change the transmission wavelength, and switches to the switching destination. The upstream data signal is transmitted to the station side device. Then, the switching-source station-side device notifies the integrated control unit of a transmission completion notification to the effect that there is no upstream data signal from the switching-target subscriber-side device in the buffer of the switching-source station-side device.

  In the second network control method of the present invention, the following processing is performed. First, the integrated control unit sends a suspension notice to the switching source station side device. Next, the integrated control unit notifies link information to the switching-destination station-side device, and instructs the connection with the switching-target subscriber-side device. Next, the switching source station side apparatus instructs the switching target subscriber side apparatus to change the transmission wavelength, and causes the switching destination station side apparatus to transmit an uplink data signal. Next, the integrated control unit is notified that there is no upstream data signal from the switching target subscriber side device in the buffer of the switching source station side device.

  According to the first control method of the present invention, while the downlink data signal is buffered in the switching destination station side device, all the downlink data signals in the switching source station side device are sent to the subscriber side device, When there is no downlink data signal in the switching source station side device, transmission from the switching destination station side device is started. According to the second control method of the present invention, when there is no upstream data signal in the switching source station side apparatus, transmission from the subscriber side apparatus to the switching destination station side apparatus is started.

  At this time, since the link information is taken over via the integrated control unit, it is not necessary to newly perform a discovery sequence. For this reason, the station-side device can be switched without reducing communication efficiency such as communication interruption.

It is a schematic block diagram of TDM / WDM-PON. It is a figure which shows the relationship between the station side port of AWGR, a subscriber side port, and a wavelength. It is a schematic block diagram of a station side apparatus. It is a schematic block diagram of a subscriber side apparatus. It is a sequence diagram for demonstrating a 1st control method. It is a sequence diagram for demonstrating the 2nd control method.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the arrangement and connection relationship of each component are merely schematically shown to the extent that the present invention can be understood. In the following, a preferred configuration example of the present invention will be described. However, numerical conditions and the like are merely preferred examples. Therefore, the present invention is not limited to the following embodiments, and many changes or modifications that can achieve the effects of the present invention can be made without departing from the scope of the configuration of the present invention.

(TDM / WDM-PON)
A schematic configuration of the TDM / WDM-PON will be described with reference to FIG. The TDM / WDM-PON 10 includes N (N is an integer of 2 or more) OLTs 100, optical routing means 200, and M (M is an integer of 1 or more) branches 300.

  The OLT 100 and the optical routing means 200 can be installed in the station 50, but the optical routing means 200 may be installed outside the station 50.

  The branch 300 includes an optical transmission line 700 configured with a single-core optical fiber, an optical splitter 400, and an ONU 500, respectively. The optical transmission line 700 is branched by the optical splitter 400, and the ONU 500 is connected to the branch destination of the optical transmission line 700, respectively. The ONU 500 is installed, for example, in a subscriber's house.

  The OLT 100 and the optical routing means 200 are connected by an optical transmission line 600 constituted by an optical fiber.

  The N OLTs 100 manage the M branches 300 and can transmit and receive data to and from the ONUs 500 included in these M branches 300.

  The OLT 100 is connected to an upper network (NW) 20. The OLT 100 converts the downlink data signal received from the upper NW 20 into a downlink optical signal, and sends it to the user terminal 30 via one of the branches 300. Further, the OLT 100 converts an upstream optical signal received from the user terminal 30 via any one of the branches 300 into an upstream data signal and sends the upstream data signal to the upper NW 20.

  The TDM / WDM-PON 10 includes a host switch (SW) 110 and an integrated control unit 120 in the station 50. The upper SW 110 sends the downlink data signal to the OLT 100 determined according to the destination of the downlink data signal. Further, the upper SW 110 sends the upstream data signal received from each OLT 100 to the upper NW 20. In addition, the upper SW 110 notifies the integrated control unit 120 of traffic information such as traffic and a destination of a downlink data signal transmitted from the upper NW 20.

  The integrated control unit 120 manages PON link information of the TDM / WDM-PON 10 as link information. The integrated control unit 120 receives information on the ONU registered in the OLT 100, that is, the ONU with which the PON link is established, from the station-side control unit of each OLT 100, and uses RAM (Random Access Memory) as the PON link information. ) And the like (not shown in the figure). Further, the integrated control unit 120 creates a transmission plan based on the traffic information received from the upper SW and the PON link information. Further, the integrated control unit 120 generates a wavelength setting signal based on the transmission plan and sends it to the OLT 100. Further, the integrated control unit 120 generates a routing table and sends it to the upper SW 110. The upper SW 110 sets a route based on the routing table.

  Although FIG. 1 shows a configuration example including four OLTs 100-1 to 4 and four branches 300-1 to 300-4, the number of OLTs 100 and branches 300 is not limited to this. In the following description, when a plurality of OLTs 100 are provided in the station 50, the plurality of OLTs 100, the integrated control unit 120, and the upper SW 110 may be collectively referred to as an integrated OLT.

  The optical routing means 200 is, for example, an arrayed optical waveguide router (AWGR) configured by arranging optical wavelength filters, and has a plurality of optical communication ports that can input and output optical signals.

  The plurality of optical communication ports are divided into a first group connected to the OLT 100 via the optical transmission line 600 and a second group connected to the optical transmission line 700 of the branch 300. The optical routing unit 200 outputs the optical signal input to the optical communication port of one group from the optical communication port of the other group determined according to the wavelength of the optical signal.

  In the following description, the optical communication port 220 included in the first group is also referred to as a station-side port 220. The optical communication port 230 included in the second group is also referred to as a subscriber side port 230. In the configuration example shown in FIG. 1, the first to fourth station-side ports 220-1 to 220-4 are connected to the first to fourth OLTs 100-1 to 4 in a one-to-one correspondence. The first to fourth subscriber-side ports 230-1 to 230-4 are connected to the first to fourth branches 300-1 to 300-4 in a one-to-one correspondence.

In AWGR, a wavelength lambda as a reference, the wavelength lambda + n [lambda _FSR apart by an integral multiple of lambda _FSR from lambda is treated as the same wavelength (Here, n is an integer other than 0). This characteristic is called AWGR circulation, and λ _FSR is called free spectrum range. Therefore, in AWGR, when an optical signal having a wavelength satisfying the above relationship is input to an optical communication port in one group, the optical signal is output from the optical communication port in the other group determined by the wavelength λ.

  FIG. 2 shows an example of the relationship between the wavelengths of the upstream optical signal and downstream optical signal and the numbers of the station side port 220 and the subscriber side port 230 that are input and output.

In this embodiment, the downstream optical signal input to the station side port 220 is set to one of λ1 to λ4 as shown in FIG. 2, and the upstream optical signal input to the subscriber side port is It is set to a value obtained by adding nλ _FSR to each wavelength of λ1 to λ4.

For example, the downstream optical signal having the wavelength λ1 input to the first station-side port 220-1 is output from the first subscriber-side port 230-1 and input to the first subscriber-side port 230-1. The upstream optical signal having the wavelength λ1 + nλ _FSR is output from the first station-side port 220-1. Further, the downstream optical signal of wavelength λ2 input to the first station side port 220-1 is output from the second subscriber side port 230-2 and input to the second subscriber side port 230-2. The upstream optical signal having the wavelength λ2 + nλ _FSR is output from the first station-side port 220-1.

  As described above, the first to fourth station-side ports 220-1 to 220-4 are connected to the first to fourth OLTs 100-1 to 4 in a one-to-one correspondence with each other. The subscriber-side ports 230-1 to 230-4 are connected to the first to fourth branches 300-1 to 300-4 in a one-to-one correspondence. Accordingly, each OLT 100 can select one branch of the M branches 300 and transmit the downstream optical signal by changing the wavelength of the downstream optical signal. On the other hand, each ONU 500 can select one of the N OLTs 100 and transmit the upstream optical signal by changing the wavelength of the upstream optical signal.

  The downlink control signal generated by the station-side generation unit 160 may include information on the downstream optical signal and the wavelength of the upstream optical signal in addition to the information on the transmission timing of the upstream optical signal.

(Station equipment)
The OLT 100 will be described with reference to FIG. A plurality of OLTs 100 are provided in the integrated OLT 142 and include an electric signal processing unit 150 and an optical signal processing unit 170.

  The electrical signal processing unit 150 includes an interface (I / F) 152, a downstream electrical signal generation unit 154, a buffer 156, an upstream electrical signal processing unit 158, and a station side control unit 160.

  Since the interface 152, the downlink electrical signal generation unit 154, the uplink electrical signal processing unit 158, and the station side control unit 160 can be configured in the same manner as any suitable known OLT, detailed description thereof is omitted here.

  The interface 152 transmits / receives an upstream data signal and a downstream data signal to / from the upper NW. The interface 152 may have a function of sending traffic information to the station-side control unit 160.

  The downlink electrical signal generation unit 154 generates a downlink electrical signal based on the downlink data signal received from the interface 152 and the downlink control signal received from the station side control unit 160. The downstream electrical signal is sent to the buffer 156.

  The buffer 156 stores the downlink electrical signal, reads the downlink electrical signal in response to the read instruction signal received from the station-side control unit 160, and sends it to the optical signal processing unit 170. Note that the buffer 156 may be provided between the interface 152 and the downstream electrical signal generation unit 154.

  The upstream electrical signal processor 158 separates the upstream electrical signal received from the optical receiver 172 into an upstream data signal and an upstream control signal. The uplink data signal is sent to the upper SW 110 via the interface 152, and the uplink control signal is sent to the station side control unit 160. The uplink control signal includes, for example, information on the bandwidth requested by each ONU.

  The control unit includes, for example, a control signal generation unit and a buffer control unit. The control signal generation unit instructs each ONU to transmit the upstream optical signal and the transmission amount based on the upstream control signal, that is, generates a downstream control signal for controlling each ONU. The buffer control means generates a read instruction signal.

  The downlink control signal generated by the station-side generation unit 160 may include information on the downstream optical signal and the wavelength of the upstream optical signal in addition to the information on the transmission timing of the upstream optical signal.

  The optical signal processing unit 170 includes a wavelength variable light source 180, an optical receiving unit 172, and a multiplexing / demultiplexing unit 174. The wavelength tunable light source 180 includes any suitable electrical / optical conversion means capable of changing the wavelength, such as a TLD (Tunable Laser Diode). The wavelength tunable light source 180 sets the wavelength of the downstream optical signal based on the wavelength setting signal generated by the integrated control unit 120.

  The downstream optical signal generated by the wavelength tunable light source 180 is sent to each branch 300 via the multiplexing / demultiplexing unit 174 and the optical routing means 200.

  The optical receiver 172 converts the upstream optical signal sent through the multiplexing / demultiplexing unit 174 into an upstream electrical signal. The optical receiving unit 172 includes an arbitrary suitable photoelectric conversion element such as a PD (Photo Diode). The PD is set so that at least an upstream optical signal in a wavelength band that can be set by the ONU 500 can be received. The upstream electrical signal is sent to the upstream electrical signal processing unit 158.

The multiplexing / demultiplexing unit 174 transmits the downstream optical signal generated by the wavelength variable light source 180 to the optical routing unit 200 and transmits the upstream optical signal received from the optical routing unit 200 to the optical receiving unit 172. The multiplexing / demultiplexing unit 174 includes any suitable multiplexer / demultiplexer such as a WDM filter. As already described, in this embodiment, light in a wavelength band of λ1~λ4 the downstream optical signals, also in the upstream optical signal light in the wavelength band λ1 + nλ _FSR ~λ4 + nλ _FSR is used. For this reason, the upstream optical signal and the downstream optical signal can be multiplexed and demultiplexed by using the WDM filter.

(Subscriber equipment)
The configuration of the ONU 500 will be described with reference to FIG.

  As shown in FIG. 4, in this embodiment, an ONU 500 is configured including an electrical signal processing unit 550 and an optical signal processing unit 570.

  The electrical signal processing unit 550 includes an interface (I / F) 552, a buffer 556, an upstream electrical signal generation unit 554, a downstream electrical signal processing unit 558, and a subscriber side control unit 560. The optical signal processing unit 570 includes an optical transmission unit 580, an optical reception unit 572, a multiplexing / demultiplexing unit 574, and a wavelength variable filter 576.

  In order to make the transmission wavelength variable, a wavelength variable light source such as TLD is used for the optical transmitter 580. Further, the band of the optical receiver 572 may be set to include the wavelength set for the downstream optical signal.

  In TDM / WDM-PON, downstream optical signals having different wavelengths may be transmitted from a plurality of OLTs to one branch. For this reason, each ONU does not receive an optical signal from an OLT other than the OLT with which the PON link is established, and therefore a wavelength variable filter 576 is provided on the OLT side of the optical receiving unit 572. If a plurality of OLTs cooperate with each other and these optical signals do not interfere with each other, the wavelength variable filter 576 may be omitted.

  Setting of the wavelengths of the wavelength tunable light source 580 and the wavelength tunable filter 576 is performed, for example, by an instruction from the subscriber-side control unit 560 based on a downlink control signal. Since other configurations are the same as those of the conventional ONU, description thereof is omitted.

(Control method)
In the following description, the first OLT manages all ONUs included in the first branch, and the second OLT manages all ONUs included in the second branch. An example of switching the upstream optical signal transmission destination or the downstream optical signal transmission source OLT from the second OLT to the first OLT for a part or all of the ONUs included in the branch will be described.

  That is, the first OLT is the switching destination OLT, and the second OLT is the switching source OLT. The ONU included in the second branch is the ONU to be switched. Here, a case where there is one switching source OLT and one switching destination OLT will be described, but the present invention is not limited to this. That is, switching from one or more switching source OLTs to one or more switching destination OLTs is possible.

  In the following description, the downlink data signal, and the downstream optical signal and downstream electrical signal including the downstream data signal are simply referred to as downstream signal, and the upstream data signal and the upstream optical signal and upstream electrical signal including the upstream data signal are simply referred to as downstream signal. Sometimes referred to as an upstream signal.

(First control method)
Referring to FIG. 5, as a first control method, the transmission source of the downstream optical signal to the switching target ONU is changed from the switching source second OLT (OLT2) to the switching destination first OLT (OLT1). A control method for switching will be described. FIG. 5 is a sequence diagram for explaining the first control method.

  The downlink data signal sent from the upper NW is distributed by the upper SW 110 according to the routing table. Here, the downlink data signal addressed to the first branch (branch 1) 300-1 is sent to the OLT 1, and the downlink data signal addressed to the second branch (branch 2) 300-2 is sent to the OLT 2. .

  The PON link information between the OLT 1 and the branch 1 and the PON link information between the OLT 2 and the branch 2 are sent to the integrated control unit 120 and managed (S10). Note that S10 may be omitted if the integrated control unit 120 has already acquired the PON link information at the time of switching from OLT2 to OLT1. Further, the OLT 2 may be configured to send the PON link information of the ONU to be switched to the integrated control unit 120 in response to receipt of a stop notice in S20 described later.

  Here, the OLT that transmits the downlink data signal to the ONU included in the branch 2 is switched from the OLT 2 to the OLT 1.

  In this case, the integrated control unit 120 sends a suspension notice to the switching source OLT 2 (S20). Further, the integrated control unit 120 rewrites the routing table so as to send the downlink data signal addressed to the ONU to be switched to the OLT 1. The rewritten routing table is sent to the upper SW 110 (S30). Receiving the rewritten routing table, the upper SW 110 sends a downlink data signal addressed to the ONU to be switched to the OLT 1.

  Further, the integrated control unit 120 notifies the OLT 1 of the PON link information regarding the ONU to be switched, and instructs the connection between the OLT 1 and the ONU to be switched (S40).

  After S40, the downlink data signal addressed to the ONU to be switched is sent to the OLT 1, but the OLT 1 and the OLT 2 perform the same transmission to the ONU as before. That is, the OLT 1 buffers the downlink data signal addressed to the switching target ONU and does not transmit it to the ONU. The OLT 2 continues transmission of the downlink data signal addressed to the ONU to be switched remaining in the buffer as it is.

  When the OLT 2 has transmitted all the downlink data signals addressed to the ONUs to be switched in the buffer, that is, when there are no downlink data signals destined to the ONUs to be switched in the buffer, the OLT 2 notifies the integrated control unit 120 to that effect. A transmission completion notification is sent (S50).

  The integrated control unit 120 receives the transmission completion notification from the OLT 2 and causes the OLT 1 to start transmitting a downstream optical signal to the ONU to be switched (S60). In this case, the integrated control unit 120 transmits to the OLT 1 the transmission wavelength λ1 for the ONU included in the branch 1, and transmits the transmission wavelength λ2 to the ONU to be switched included in the branch 2. Is newly created, and the transmission plan is notified to the station side control unit of the OLT 1.

  In addition, the order of the process from S20 to S60 is not limited to this example. The order of S20, S30, and S40 can be arbitrarily set. Moreover, the process of S40 can be performed after S50, and S40 and S60 may be integrated after S50.

  The OLT 1 uses the PON link information received from the integrated control unit 120 to transmit a downlink data signal to each ONU including the ONU to be switched according to a new transmission plan.

  According to this control method, when the transmission source of the downstream signal to the ONU to be switched is changed from OLT2 to OLT1, the communication is interrupted because the OLT is changed after the link between the OLT1 and the ONU for switching is established. There is nothing.

  Note that for all ONUs to which the OLT 2 has transmitted the downlink signal, when the downlink signal transmission source is switched from the OLT 2 to the OLT 1, the OLT 2 does not transmit the downlink signal. Therefore, the part related to the transmission of the downlink signal of OLT 2 can be set in the sleep state. In this case, all ONUs from which the OLT has transmitted downlink data signals are ONUs to be switched.

  When all the downlink data signals in the buffer are transmitted, that is, when there are no more downlink data signals in the buffer, the OLT 2 notifies the integrated control unit 120 as a transmission completion notification (S50).

  Receiving the communication completion notification, the integrated control unit 120 sends an instruction to the OLT 2 to put the part related to the downstream signal processing into the sleep state (S70). The part relating to the processing of the downstream signal corresponds to a variable wavelength light source of the optical signal processing unit, a downstream electrical signal generating unit of the electrical signal processing unit, and the like. The power consumption can be reduced by setting at least a part of the part related to the processing of the downlink signal to the sleep state.

  Although an example has been described here in which all ONUs managed by the OLT 2 in one branch are switched to the OLT 1, the present invention is not limited to this, and the switching destination OLT may be divided into a plurality of OLTs.

  In this first control method, a downlink signal addressed to the ONU to be switched is sent from the OLT 1, but the destination of the uplink data signal is sent to the OLT 2 without being changed.

(Second control method)
With reference to FIG. 6, a control method for switching the transmission destination of the upstream optical signal from the switching target ONU from the switching source OLT 2 to the switching destination OLT 1 will be described as a second control method. FIG. 6 is a sequence diagram for explaining the second control method.

  Here, the uplink data signal from branch 1 is sent to OLT 1, and the uplink data signal from branch 2 is sent to OLT 2.

  The PON link information between the OLT 1 and the branch 1 and the PON link information between the OLT 2 and the branch 2 are sent to the integrated control unit 120 and managed (S110). Note that S110 may be omitted if the integrated control unit 120 has already acquired the PON link information at the time of switching from OLT2 to OLT1. Further, the OLT 2 may be configured to send the PON link information of the ONU to be switched to the integrated control unit 120 in response to receiving a suspension notice in S120 described later.

  Here, the transmission destination of the uplink data signal from the ONU included in the branch 2 is switched from OLT2 to OLT1.

  In this case, the integrated control unit 120 sends a suspension notice to the switching source OLT 2 (S120).

  Further, the integrated control unit 120 notifies the OLT 1 of the PON link information related to the switching target ONU, and instructs the connection between the OLT 1 and the switching target ONU (S140).

  Next, the OLT 2 instructs the ONU to be switched to change the transmission wavelength to the wavelength for the OLT 1 (S145). In response to this instruction, the ONU to be switched transmits an uplink data signal to the OLT 1.

  The OLT 2 sends a transmission completion notification to the integrated control unit 120 when all the uplink data signals from the ONUs to be switched that have been buffered are transmitted to the upper NW (S150). In addition, the order of the process from S120 to S150 is not limited to this example. For example, the process of S120 may be performed after S140. The process of S140 may be performed after S145.

  According to this control method, when the transmission destination of the uplink data signal from the switching target ONU is changed from OLT2 to OLT1, the OLT is changed after the link between the OLT1 and the switching target ONU is established. There is no interruption.

  In addition, when the transmission destination of the upstream data signal from all ONUs that has transmitted the upstream data signal to the OLT 2 is switched from the OLT 2 to the OLT 1, the OLT 2 does not receive the upstream signal. Therefore, the part related to reception of the uplink signal can be put in the sleep state. In this case, all ONUs that have transmitted upstream data signals to the OLT are the ONUs to be switched.

  When all the uplink data signals in the buffer (not shown) are transmitted, that is, when there are no buffered uplink data signals, the OLT 2 notifies the integrated control unit 120 as a transmission completion notification. (S150).

  The integrated control unit 120 sends an instruction to the OLT 2 to put the part related to the upstream signal processing into the sleep state (S170). The portion related to the processing of the upstream signal corresponds to the optical receiving unit of the optical signal processing unit, the upstream electrical signal processing means of the electrical signal processing unit, and the like. The power consumption can be reduced by setting at least a part of the part related to the processing of the uplink signal to the sleep state.

  Also, here, an example has been described in which the transmission destinations of all ONUs that are transmitting uplink signals to OLT 2 in one branch are switched to OLT 1, but this is not a limitation, and the switching destination OLT is switched to a plurality of OLTs. May be divided.

  In the second control method, an upstream signal is transmitted from the ONU to be switched to the OLT 1, but a downstream signal is transmitted from the OLT 2 without being changed.

(Third control method)
The third control method is an integration of the first control method and the second control method. That is, according to the third control method, by executing both the first control method and the second control method, the OLT 1 transmits the downstream optical signal to the branch 2, and the upstream signal from the branch 2 is transmitted. It changes so that OLT1 may receive.

  For all ONUs that OLT2 is transmitting / receiving, when the transmission source of the downlink signal is changed to OLT1 and the transmission destination of the uplink signal is changed to OLT1, OLT2 does not receive the uplink signal and transmit the downlink signal . Therefore, the part related to the reception of the uplink signal and the transmission of the downlink signal can be put in the sleep state. In this case, all ONUs that have transmitted uplink data signals to the OLT 2 and all ONUs that have received downlink data signals from the OLT 2 are ONUs to be switched.

  After changing the transmission source of the downlink signal and the transmission destination of the uplink signal, the OLT 2 is set in the sleep state. In this sleep state, not the entire OLT, for example, a device with high power consumption may be selected to sleep.

(Fourth control method)
The fourth control method is a method that can be executed when the ONU includes a variable wavelength filter in executing the first and third control methods. When the ONU includes a variable wavelength filter, when the transmission source of the downstream optical signal to the switching target ONU is switched from OLT2 to OLT1, the switching target ONU receives the downstream optical signal because the wavelength of the received downstream optical signal changes. It may not be possible. Therefore, the OLT 2 sends a transmission completion notification to the integrated control unit 120 and instructs the ONU to be switched to switch the reception wavelength to a wavelength at which the downstream optical signal from the OLT 1 can be received.

  As a result, even if the ONU includes a variable wavelength filter, the source OLT can be changed.

10 TDM / WDM-PON
20 Upper network (upper NW)
30 user terminals
100 Station side equipment (OLT)
110 Host switch (Host SW)
120 Integrated Control Unit 142 Integrated OLT
150, 550 Electric signal processor 152, 552 Interface (I / F)
154, 558 Downstream electrical signal generation unit 156, 556 Buffer 158, 554 Upstream electrical signal processing unit 160 Station side control unit 170, 570 Optical signal processing unit 172, 572 Optical reception unit 174 Multiplexing / demultiplexing unit 180 Wavelength variable light source 200 Optical routing Means (AWGR)
300 branch 400 optical splitter 500 subscriber unit (ONU)
560 Subscriber side control unit 580 Optical transmission unit 600, 700 Optical transmission line

Claims (9)

A plurality of station side devices;
An upper switch that distributes the downlink data signal received from the upper network to the plurality of station side devices according to the routing table;
One or a plurality of branches each including a branched optical transmission line and a subscriber side device connected to a branch destination of the optical transmission line;
It has a plurality of optical communication ports divided into a first group connected to the station side device and a second group connected to the optical transmission line, and is input to the optical communication port of one group An optical routing means for outputting an optical signal from the optical communication port of the other group, which is determined according to the wavelength of the optical signal;
An integrated control unit for managing link information of each of the subscriber side devices;
A network control method comprising:
A process in which the integrated control unit sends a suspension notice to the switching source station side device;
The integrated control unit rewrites the routing table and sends a downlink data signal addressed to a switching target subscriber side device to a switching destination station side device;
The integrated control unit notifies the link information to the switching-destination station-side device, and instructs the connection with the switching-subscriber-side device;
The switching-side station-side device that has received the suspension notice sends a transmission completion notification to the effect that there is no downlink data signal addressed to the switching-target subscriber-side device in the buffer of the station-side device. The process of notifying
The integrated control unit that has received the transmission completion notification instructs the switching destination station side device to start transmission to the switching target subscriber side device;
With
further,
The integrated control unit is performed after the process of sending the suspension notice to the switching source station side device,
The switching source station side device instructs the switching target subscriber side device to change the transmission wavelength, and causes the switching destination station side device to transmit an uplink data signal;
A step of notifying the integrated control unit of a transmission completion notification to the effect that there is no upstream data signal from the switching target subscriber side device in the buffer of the switching source station side device. Rene Ttowaku control method of.   A plurality of station side devices;
  An upper switch that distributes the downlink data signal received from the upper network to the plurality of station side devices according to the routing table;
  One or a plurality of branches each including a branched optical transmission line and a subscriber side device connected to a branch destination of the optical transmission line;
  It has a plurality of optical communication ports divided into a first group connected to the station side device and a second group connected to the optical transmission line, and is input to the optical communication port of one group An optical routing means for outputting an optical signal from the optical communication port of the other group, which is determined according to the wavelength of the optical signal;
  An integrated control unit for managing link information of each of the subscriber side devices;
A network control method comprising:
  A process in which the integrated control unit sends a suspension notice to the switching source station side device;
  The integrated control unit rewrites the routing table and sends a downlink data signal addressed to a switching target subscriber side device to a switching destination station side device;
  The switching-side station-side device that has received the suspension notice sends a transmission completion notification to the effect that there is no downlink data signal addressed to the switching-target subscriber-side device in the buffer of the station-side device. The process of notifying
  Upon receiving the transmission completion notification, the integrated control unit notifies the switching destination station side device to instruct connection with the switching target subscriber side device, and the switching target subscriber side A process of instructing the device to start transmission;
With
  further,
  The integrated control unit is performed after the process of sending the suspension notice to the switching source station side device,
  The switching source station side device instructs the switching target subscriber side device to change the transmission wavelength, and causes the switching destination station side device to transmit an uplink data signal;
  A process of notifying the integrated control unit of a transmission completion notification indicating that there is no uplink data signal from the switching target subscriber side device in the buffer of the switching source station side device;
With
A network control method characterized by the above. A plurality of station side devices;
One or a plurality of branches each including a branched optical transmission line and a subscriber side device connected to a branch destination of the optical transmission line;
It has a plurality of optical communication ports divided into a first group connected to the station side device and a second group connected to the optical transmission line, and is input to the optical communication port of one group An optical routing means for outputting an optical signal from the optical communication port of the other group, which is determined according to the wavelength of the optical signal;
A network control method including an integrated control unit that manages link information of each of the subscriber side devices,
A process in which the integrated control unit sends a suspension notice to the switching source station side device;
The integrated control unit notifies the link information to the switching-destination station-side device, and instructs the connection with the switching-subscriber-side device;
The switching-source station-side device that has received the suspension notice instructs the switching-target subscriber-side device to change the transmission wavelength, and causes the switching-destination station-side device to transmit an uplink data signal. Process,
A step of notifying the integrated control unit of a transmission completion notification indicating that there is no upstream data signal from the switching target subscriber side device in the buffer of the switching source station side device. Network control method. All subscriber-side devices registered in the switching-source station-side device are the subscriber-side devices to be switched,
In the buffer of the switching source station side device, after the process of notifying the integrated control unit of the transmission completion notification that there is no downlink data signal,
3. The network control method according to claim 1, wherein the integrated control unit performs a process of sending a sleep instruction to set a part related to downlink signal processing to a sleep state to the switching source station side device. 4. . All subscriber-side devices registered in the switching-source station-side device are the subscriber-side devices to be switched,
In the buffer of the switching source station side device, after the process of notifying the integrated control unit of the transmission completion notification that there is no upstream data signal,
The network control method according to claim 3, wherein the integrated control unit performs a process of sending a sleep instruction for setting a part related to uplink signal processing to a sleep state to the switching source station side apparatus. All subscriber-side devices registered in the switching-source station-side device are the subscriber-side devices to be switched,
In the process of notifying the integrated control unit of a transmission completion notification that there is no downlink data signal in the buffer of the switching source station side apparatus, and in the buffer of the switching source station side apparatus After the process of notifying the integrated control unit of the transmission completion notification that the signal is lost,
The integrated control unit, the sleep instruction to sleep a central terminal of the switching換元, control of the network according to claim 1 or 2, characterized in that the step of sending the line terminal of the switching換元Method. When the subscriber-side device includes a wavelength tunable filter that transmits a downstream optical signal from a station-side device in which the subscriber-side device is registered and blocks a downstream optical signal from another station-side device,
In the process of notifying the integrated control unit of the transmission completion notification that there is no downlink data signal addressed to the subscriber side device to be switched in the buffer of the station side device, the switching source station side device, the subscriber unit of the switching target, claims 1, 2, 4 and any one of 6 and performing the switching instruction to the reception possible wavelengths downstream optical signal from the optical line terminal of the switching destination The network control method according to the item. The switching source station side device, which is performed before or after the process of sending the suspension notice, includes a step of notifying the integrated control unit of link information of a subscriber side device to be switched. The network control method according to any one of 1 to 7 . The method of network according to any one of claims 1-8, wherein the link information is PON link information.

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