JP5383844B2 - Station side communication apparatus, subscriber side communication apparatus, communication system, communication method, and control apparatus - Google Patents

Description

  The present invention relates to a PON (Passive Optical Network) system using Ethernet (registered trademark) technology.

  Conventionally, a PON system, which is a method of FTTH (Fiber To The Home), has rapidly spread because an access network connecting a station and a user's home can achieve high speed and economy. In a PON system, a plurality of subscriber-side devices (ONU: Optical Network Unit) are connected to a station-side device (OLT: Optical Line Termination) via an optical splitter that branches signal outputs to a plurality of optical fibers. . A TE (Terminal Equipment) is connected to the ONU via a LAN cable. TE is, for example, HGW (Home Gate Way), VoIP-TA (Voice over Internet Protocol-Terminal Adapter), PC, and the like.

  By the way, the ONU installed in the user's home provides services that require real-time performance such as optical telephones, so even when data communication is not performed (during standby), it is always linked to OLT and TE. There is a problem that the power consumption of ONU is large.

  In order to solve the above problem, in Patent Document 1 below, in the call-by-call control with a PDS (passive double star) configuration, a specific pattern is set for each terminal line termination device. The line termination device compares the specific pattern transmitted from the intra-station line termination device with the setting (registration) pattern within itself and configures the incoming call operation only when they match, thereby reducing unnecessary power consumption. A method of suppression is disclosed.

  Further, in Patent Document 2 below, when there is no effective data exchange between a modem and a line card in an ATM (Asynchronous Transfer Mode) device, the function of the modem and the transmission unit of the line card is stopped. Thus, a method for suppressing unnecessary power consumption is disclosed.

  Patent Document 3 below discloses a method for monitoring the state of a logical link and a physical link in an ONU of a PON system and controlling an on-board circuit in the ONU to a low power consumption mode when the link is disconnected. Has been.

JP-A-9-64903 JP 2004-64458 A JP 2008-113193 A

  However, according to the methods of Patent Documents 1 and 2, since the operation is performed only when a predetermined condition for performing communication is satisfied, the link state between the intra-station line terminator and the subscriber line terminator can be maintained. There was a problem that it was not possible.

  Further, in the method of Patent Document 3 above, since only the presence or absence of a link is used as a trigger as a trigger for transitioning to the low power consumption mode, it is not assumed that the link is established but there is no user data. There was a problem that the power consumption reduction operation of the case was not shown.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a PON system capable of reducing the power consumption of the ONU while maintaining the link between the OLT and the ONU.

In order to solve the above-described problems and achieve the object, the station side communication device of the present invention is connected to the subscriber side communication device via an optical fiber, and controls the state of the link with the subscriber side communication device. PON (Passive Optical Network) Oite the station-side communication device for the system having a control unit for the control unit, downstream to transition the operation mode of the uplink communication of the subscriber-side communication apparatus to the low power consumption state The first low power consumption mode in which the communication operation mode is not changed to the low power consumption state, and the uplink communication operation mode and the downlink communication operation mode of the subscriber side communication device are changed to the low power consumption state. A control signal in which any one of the second low power consumption modes is specified is generated, and the generated control signal is transmitted to the subscriber side communication device and transmitted from the control unit. The above system When based on the low power consumption mode specified in the signal the subscriber-side communication device is operating in the first or second power saving mode, and該局side communication device and the subscriber-side communication device It is characterized by suppressing the disconnection of the link between the two . The station side communication device of the present invention is a station side communication device of a PON (Passive Optical Network) system connected to a subscriber side communication device via an optical fiber, in the upstream communication of the subscriber side communication device, and Of the downlink communication, a control signal carrying a communication direction for transition to a low power consumption state is transmitted to the subscriber side communication device, and the subscriber side is based on the communication direction carried in the transmitted control signal. When the communication device is operating in a low power consumption state, a control unit is provided that suppresses disconnection of the link with the subscriber-side communication device.

Subscriber-side communication device of the invention, the station-side communication device and connected through an optical fiber PON (Passive Optical Network) Oite subscriber side communication device for the system, the subscriber-side communication device, the first low power consumption mode which does not transition the operation mode of the downlink communication to transition the operation mode of the uplink communication of the subscriber-side communication apparatus to the low power consumption state to the low power consumption state, and, the subscriber-side communication device Control signal in which any one of the low power consumption modes is designated among the second low power consumption modes for transitioning the operation mode of the uplink communication and the operation mode of the downlink communication to the low power consumption state. Transition from the device to the first or second low power consumption mode based on the low power consumption mode specified in the received control signal , and transition to the first or second low power consumption mode rear The subscriber-side communication apparatus, in a state in which the said subscriber communication device and the station-side communication apparatus is maintained linked together, to the operation by the first or second power saving mode Features.
A subscriber-side communication device according to the present invention is a subscriber-side communication device of a PON (Passive Optical Network) system connected to a station-side communication device via an optical fiber. In the direction communication, a control signal carrying a communication direction for transition to a low power consumption state is transmitted to the station side communication device, and a state where the link between the subscriber side communication device and the station side communication device is maintained A subscriber-side communication apparatus comprising: a control unit that shifts an operation mode in a communication direction that transitions to the low power consumption state to a low power consumption state.

Communication system of the invention includes a station-side communication instrumentation 置及 beauty subscriber side communication equipment in a communication system for performing communication in a state where between the station-side communication device and the subscriber-side communication devices are linked, The station side communication device is a first low power consumption mode in which an operation mode of uplink communication of the subscriber side communication device is changed to a low power consumption state and an operation mode of downlink communication is not changed to a low power consumption state; In addition, any one of the low power consumption modes is designated out of the second low power consumption mode for transitioning the uplink communication operation mode and the downlink communication operation mode of the subscriber side communication device to the low power consumption state. A first control unit that generates a control signal; and a transmission unit that transmits the control signal generated by the first control unit to the subscriber-side communication device , wherein the subscriber-side communication device includes: , said Receiving means for receiving the control signal transmitted from the side communication apparatus, based on the low power consumption mode specified in the control signal received by the receiving means, to the first or second power saving mode A second control unit that executes transition, wherein the first control unit provided in the station side communication device is configured to change the subscriber side communication that has transitioned to the first or second low power consumption mode. When the device is operating in the low power consumption mode, the disconnection of the link between the station side communication device and the subscriber side communication device is suppressed.

Communication method of the present invention includes a station-side communication instrumentation 置及 beauty subscriber side communication equipment, the communication of the communication system for performing communication in a state where between the station-side communication device and the subscriber-side communication devices are linked In the method, a first low power consumption in which the station side communication device does not change the uplink communication operation mode of the subscriber side communication device to the low power consumption state and does not change the downlink communication operation mode to the low power consumption state. Any one of the low power consumption modes among the mode and the second low power consumption mode for transitioning the operation mode of the uplink communication and the operation mode of the downlink communication of the subscriber side communication device to the low power consumption state a first step of generating a specified control signal, a second step of the first of said station side communication apparatus the control signal generated by step is transmitted to the subscriber-side communication device, wherein A third step of the control signal transmitted by the second step for receiving said subscriber-side communication apparatus, based on the third low-power consumption mode specified in the received said control signal by a step of the the subscriber communication device, a fourth step of transitioning to the first or second power saving mode, the subscriber a transition to the first or second power saving mode by said fourth step A fifth step of suppressing disconnection of a link between the subscriber side communication device and the station side communication device when the side communication device is operating in the first or second low power consumption mode; It is characterized by having.
The communication method of the present invention is a communication method of a communication system comprising a station side communication device and a subscriber side communication device, and performing communication in a state where the station side communication device and the subscriber side communication device are linked. The subscriber-side communication device transmits a control signal carrying a communication direction for transitioning to a low power consumption state among the uplink communication and the downlink communication of the subscriber-side communication device to the station-side communication device; The subscriber side communication device transitions the communication mode operation mode carried in the control signal to the low power consumption state, and when the subscriber side communication device is operating in the low power consumption state, Suppressing the disconnection of the link between the subscriber side communication device and the station side communication device.
A control device according to the present invention is a control device in a station side communication device of a PON (Passive Optical Network) system connected to a subscriber side communication device via an optical fiber, and the upstream communication of the subscriber side communication device And, in the downlink communication, a control signal carrying a communication direction for transition to a low power consumption state is transmitted to the subscriber side communication device, and the subscriber is based on the communication direction carried in the transmitted control signal. When the communication device on the side is operating in a low power consumption state, disconnection of the link with the communication device on the subscriber side is suppressed.
The control device of the present invention is a control device in a subscriber-side communication device of a PON (Passive Optical Network) system connected to a station-side communication device via an optical fiber, and the upstream communication of the subscriber-side communication device And a control signal carrying a communication direction for transition to a low power consumption state in the downlink communication is transmitted to the station side communication device, and a link between the subscriber side communication device and the station side communication device is maintained. The operation mode in the communication direction for transitioning to the low power consumption state is transitioned to the low power consumption state.

  The station side communication device (OLT), the subscriber side communication device (ONU), the communication system, and the communication method according to the present invention can reduce the power consumption of the ONU while maintaining the link state between the OLT and the ONU. There is an effect.

FIG. 1 is a diagram illustrating a configuration example of the PON system according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example of the PON system according to the second embodiment. FIG. 3 is a diagram illustrating a configuration example of the PON system according to the third embodiment. FIG. 4 is a diagram illustrating a configuration example of the PON system according to the fourth embodiment.

  Hereinafter, embodiments of a PON system according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a PON system according to the present embodiment. The PON system in FIG. 1 includes a host device 1, an OLT 2 that is a station side device, a splitter 3, an ONU 4 that is a subscriber side device, and a TE 10. In FIG. 1, only one ONU 4 and TE 10 are shown, but a plurality of ONUs 4 and TEs 10 can actually be connected. The host device 1 manages the OLT 2 installed on the network side. The splitter 3 branches the optical signal from the OLT 2 and transmits it to the ONU 4. The TE 10 is, for example, HGW, VoIP-TA, PC, or the like.

  The OLT 2 includes a buffer unit 21, a frame multiplexing unit 22, an optical transmission unit 23, an optical reception unit 24, a frame separation unit 25, a PON control unit 26, a downlink traffic monitoring unit 27, a link management unit 28, And a low consumption determination unit 29. The buffer unit 21 temporarily accumulates data received from the host device 1. The frame multiplexing unit 22 multiplexes the user frame and the control frame. The optical transmission unit 23 converts the electrical signal output from the frame multiplexing unit 22 into an optical signal and transmits it to the ONU 4. The optical receiver 24 receives the optical signal from the ONU 4 and converts it into an electrical signal. The frame separation unit 25 separates the control frame and the user frame. The PON control unit 26 processes a control frame transmitted / received between the OLT 2 and the ONU 4. The downstream traffic monitoring unit 27 monitors the presence or absence of downstream traffic. The link management unit 28 manages the link state with the ONU 4. The low consumption determination unit 29 determines an ONU and a communication direction for reducing power consumption.

  The ONU 4 includes a buffer unit 41, a frame multiplexing unit 42, an optical transmission unit 43, an optical reception unit 44, a frame separation unit 45, a PON control unit 46, an upstream traffic monitoring unit 47, and a low-consumption block determination. Unit 48 and a low-consumption instruction / cancellation unit 49. The buffer unit 41 temporarily accumulates data from the TE 10. The frame multiplexing unit 42 multiplexes the user frame and the control frame. The optical transmitter 43 converts the electrical signal from the self ONU into an optical signal and transmits it to the OLT 2. The optical receiver 44 receives the optical signal from the OLT 2 and converts it into an electrical signal. The frame separation unit 45 separates the control frame and the user frame. The PON control unit 46 processes a control frame transmitted / received between the ONU 4 and the OLT 2. The upstream traffic monitoring unit 47 monitors the upstream traffic by monitoring the data amount of the buffer unit 41. The low power consumption block determination unit 48 determines a block whose power consumption is to be reduced. The low consumption instruction / cancellation unit 49 instructs or cancels the low power consumption for the blocks determined by the low consumption block determination unit 48.

  In this PON system, as a conventional operation, a control frame (described later) is exchanged between the PON control unit 26 of the OLT 2 and the PON control unit 46 of the ONU 4 to confirm the contents thereof in order to maintain the link. Data communication is performed only when the link is maintained.

  Next, the operation of the PON system configured as described above will be described. Hereinafter, the case will be described separately based on the link state of the PON section and the uplink and downlink traffic states.

(Case 1-1) When the link in the PON section is established and there is no traffic in both uplink and downlink.
The upstream traffic monitoring unit 47 of the ONU 4 monitors the upstream traffic from the TE 10 by monitoring the buffer unit 41, and detects that there is no upstream traffic from the TE 10 when there is no accumulated data amount for a predetermined time. In this case, the upstream traffic monitoring unit 47 notifies the PON control unit 46 that there is no upstream traffic. On the other hand, as a conventional operation, the OLT 2 periodically transmits a control frame (hereinafter referred to as “inquiry frame”) for making an inquiry about the amount of accumulated data for the purpose of link confirmation and uplink bandwidth allocation calculation. When the inquiry frame is received via the optical receiving unit 44 and the frame separation unit 45, the PON control unit 46 transmits a control frame including the accumulated data amount notified from the buffer unit 41 (hereinafter referred to as “inquiry response frame”). "). Here, since there is notification from the upstream traffic monitoring unit 47 that there is no upstream traffic, the PON control unit 46 further includes that fact in the control frame.

  The low consumption determination unit 29 of the OLT 2 receives the inquiry response frame via the optical reception unit 24 and the frame separation unit 25. Further, the downstream traffic monitoring unit 27 monitors the data storage state of the buffer unit 21 and, when there is no data addressed to the ONU 4 for a certain period of time, notifies the low consumption determination unit 29 that there is no traffic addressed to the ONU 4. . As described above, the low-consumption determination unit 29 is notified that there is no accumulated data in the ONU 4 and that there is no traffic addressed to the ONU 4, so it determines that there is no upstream or downstream traffic with the ONU 4, and determines the ONU 4 It decides to make a transition to the low power consumption mode in both the uplink and downlink directions, and instructs the PON control unit 26 to notify that. The PON control unit 26 transmits a control frame (hereinafter also referred to as “transition instruction frame”) including the content of the notification (the transition to the low power consumption mode and the communication direction to be transitioned) to the frame multiplexing unit 22 and the optical It transmits to ONU4 via the transmission part 23.

  The low consumption block determination unit 48 of the ONU 4 receives the transition instruction frame via the optical reception unit 44 and the frame separation unit 45. The low-consumption block determination unit 48 receives data from the OLT 2 and transmits it to the TE 10 in accordance with the instruction in the transition instruction frame, that is, the instruction to shift the uplink and downlink of the own ONU to the low power consumption mode. The block, the block that receives data from TE10 and transmits it to OLT2, and the block that is necessary for communication control with OLT2, are shifted to the low power consumption mode. That is, the low consumption block determination unit 48 includes a frame multiplexing unit 42, an optical transmission unit 43, an optical reception unit 44, a frame separation unit 45, a PON control unit 46, an upstream traffic monitoring unit 47, a low consumption block determination unit 48, Is determined to be a block to be changed to the low power consumption mode, and the fact is notified to the low consumption instruction / cancellation unit 49.

  The low consumption instruction / cancellation unit 49, for example, designates a time determined in advance in the PON system and set in the ONU 4, and instructs the block to make a transition to the low power consumption mode. Hereinafter, the “time” in the ONU 4 is also referred to as “low power consumption operating time”. The time may be indicated in the transition instruction frame transmitted by the OLT 2.

  By the way, the PON control unit 26 of the OLT 2 can expect that the communication between the OLT 2 and the ONU 4 is interrupted while the ONU 4 is transitioning to the low power consumption mode according to the instruction of the transition instruction frame. For this reason, the PON control unit 26 is set in advance in the PON system and set in the own OLT (or specified in the transition instruction frame transmitted from the own OLT so as not to break the link with the ONU 4. The process of monitoring the link is stopped until the time elapses. That is, the periodic inquiry frame transmission to the corresponding ONU (ONU4) is stopped, and the link state held by the link management unit 28 is maintained.

  During this time, in the OLT 2, when traffic addressed to the corresponding ONU (ONU 4) arrives from the host device 1, it is stored in the buffer unit 21.

  Similarly, in the ONU 4, when traffic addressed to the OLT 2 arrives from the TE 10, it is stored in the buffer unit 41.

  When the operation time of the low power consumption mode expires in the ONU 4, the low power consumption instruction / cancellation unit 49 of the ONU 4 transmits an instruction to cancel the low power consumption mode to each of the blocks, and activates each block. Further, when the low power consumption mode operation time expires in the OLT 2, the PON control unit 26 of the OLT 2 resumes link monitoring by resuming a periodic inquiry to the corresponding ONU (ONU 4).

  As a result, when there is no up / down traffic in the ONU 4, it is possible to reduce the power consumption of blocks unnecessary for communication with the OLT 2 while maintaining the link with the OLT 2. As for the traffic generated while the ONU 4 is operating in the low power consumption mode, the downlink traffic is accumulated in the buffer unit 21 of the OLT 2 and the uplink traffic is accumulated in the buffer unit 41 of the ONU 4 and is transmitted / received when resuming. It can be operated in low power consumption mode while avoiding loss.

(Case 1-2) When the link in the PON section is established and there is no downlink traffic.
Next, an operation when only downlink traffic is stopped will be described. The downstream traffic monitoring unit 27 of the OLT 2 monitors the data storage state of the buffer unit 21 and notifies the low-consumption determination unit 29 that there is no downstream traffic addressed to the ONU 4 when there is no data addressed to the ONU 4 over a certain time. To do. Further, the low consumption determination unit 29 refers to the inquiry response frame transmitted from the ONU 4 as described above, and recognizes that there is accumulated data in the ONU 4. From the above, the low consumption determination unit 29 of the OLT 2 determines that there is no downlink traffic for the ONU 4 alone. Therefore, the low consumption determination unit 29 determines to shift the downlink direction from the own apparatus to the ONU 4 to the low power consumption mode, and instructs the PON control unit 26 to notify the fact. The PON control unit 26 transmits a transition instruction frame including the content of the notification to the ONU 4 via the frame multiplexing unit 22 and the optical transmission unit 23.

  When the ONU 4 low-consumption block determination unit 48 receives the transition instruction frame via the optical reception unit 44 and the frame separation unit 45, it receives data from the OLT 2 and transmits it to the TE 10, and communication with the OLT 2 It is determined that a block necessary for control is shifted to the low power consumption mode. That is, the low-consumption block determination unit 48 is a block for causing the optical reception unit 44, the frame separation unit 45, the PON control unit 46, the uplink traffic monitoring unit 47, and the low-consumption block determination unit 48 to transition to the low power consumption mode. And notifies the low consumption instruction / cancellation unit 49 to that effect.

  The low power consumption instruction / cancellation unit 49 designates the low power consumption operating time to the corresponding block and instructs to shift to the low power consumption mode.

  Further, the PON control unit 26 of the OLT 2 can expect that the communication between the OLT 2 and the ONU 4 is interrupted while the ONU 4 is transitioning to the low power consumption mode according to the instruction of the transition instruction frame. For this reason, the PON control unit 26 is set in advance in the PON system and set in the own OLT (or specified in the transition instruction frame transmitted from the own OLT so as not to break the link with the ONU 4. The process of monitoring the link is stopped until the time elapses. That is, the periodic inquiry frame transmission to the corresponding ONU (ONU4) is stopped, and the link state held by the link management unit 28 is maintained.

  By the way, the ONU 4 cannot transmit control information even when uplink traffic occurs by switching the block related to downlink traffic and the block related to exchange of control information with the OLT 2 to the low power consumption mode. The permission will not be obtained. In response to this, the PON control unit 26 of the OLT 2 uses the statistical information held so far, the minimum bandwidth guarantee information in the PON system, etc. according to the low power consumption operating time etc. The transmission permission is transmitted to ONU4. Further, while the ONU 4 is transitioning to the low power consumption mode, the OLT 2 stores the traffic addressed to the corresponding ONU (ONU 4) in the buffer unit 21 when the traffic arrives from the host device 1.

  When the low power consumption operation time in the ONU 4 expires, the low power consumption instruction / cancellation unit 49 of the ONU 4 instructs the above blocks to cancel the low power consumption mode, and activates each block. On the other hand, in the OLT 2, when the time during which the ONU 4 is transitioning to the low power consumption mode has expired, the link management unit 28 resumes the instruction to the PON control unit 26 for periodic inquiry frame transmission to the corresponding ONU (ONU 4). By doing so, link monitoring is resumed.

  As a result, when there is no downlink traffic, it is possible to reduce the power consumption of blocks unnecessary for downlink traffic transmission by maintaining the link and preliminarily granting uplink traffic transmission permission. Also, since the downlink traffic generated during the transition to the low power consumption mode is accumulated in the buffer unit 21 of the OLT 2 and transmitted when the downlink traffic is resumed, the occurrence of frame loss can be avoided.

(Case 1-3) A link in the PON section is established and there is no uplink traffic only.
Next, the operation when only the upstream traffic is stopped will be described. As described above, the buffer unit 41 of the ONU 4 notifies the PON control unit 46 of the data accumulation amount. Further, the uplink traffic monitoring unit 47 monitors the uplink traffic from the TE 10, and when detecting that there is no uplink traffic from the TE 10 for a certain time, notifies the PON control unit 46 of that fact. When the PON control unit 46 receives an inquiry frame from the OLT 2 via the optical reception unit 44 and the frame separation unit 45, the PON control unit 46 creates an inquiry response frame including the data accumulation amount notified from the buffer unit 41. Here, the PON control unit 46 performs control to send back an inquiry response frame further including the fact that there is no uplink traffic based on the notification from the uplink traffic monitoring unit 47.

  When receiving the inquiry response frame via the optical receiver 24 and the frame separator 25, the low consumption determination unit 29 of the OLT 2 recognizes that there is no accumulated data amount in the ONU 4. On the other hand, the downstream traffic monitoring unit 27 does not detect that there is no downstream traffic. Accordingly, the PON control unit 26 determines that there is only no upstream traffic from the ONU 4, determines to transition to the low power consumption mode in the upstream direction from the ONU 4, and notifies the fact to that effect. To instruct. The PON control unit 26 transmits to the ONU 4 a transition instruction frame for instructing a transition to the low power consumption mode in the uplink direction.

  When the ONU 4 low-consumption block determination unit 48 receives the transition instruction frame via the optical reception unit 44 and the frame separation unit 45, the block that receives data from the TE 10 and transmits the data to the OLT 2 and the communication with the OLT 2 It is determined to shift a block required for control to the low power consumption mode. That is, the frame multiplexing unit 42 and the optical transmission unit 43 (blocks related to transmission processing), the PON control unit 46, the uplink traffic monitoring unit 47, and the low consumption block determination unit 48 (blocks related to communication control) are set to the low power consumption mode. It is determined as a block to be transitioned, and the fact is notified to the low consumption instruction / cancellation unit 49.

  The low power consumption instruction / cancellation unit 49 designates the low power consumption operating time to the corresponding block and instructs to shift to the low power consumption mode.

  Further, the PON control unit 26 of the OLT 2 can expect that the communication between the OLT 2 and the ONU 4 is interrupted while the ONU 4 is transitioning to the low power consumption mode according to the instruction of the transition instruction frame. For this reason, the PON control unit 26 is set in advance in the PON system and set in the own OLT (or specified in the transition instruction frame transmitted from the own OLT so as not to break the link with the ONU 4. The process of monitoring the link is stopped until the time elapses. That is, the periodic inquiry frame transmission to the corresponding ONU (ONU4) is stopped, and the link state held by the link management unit 28 is maintained.

  When traffic addressed from the TE 10 to the OLT 2 arrives at the ONU 4 until the low power consumption operating time elapses, the buffer unit 41 accumulates the traffic. When the low power consumption operation time in the ONU 4 expires, the low power consumption instruction / cancellation unit 49 of the ONU 4 instructs the above blocks to cancel the low power consumption mode, and activates each block. On the other hand, in the OLT 2, when the time during which the ONU 4 is transitioning to the low power consumption mode expires, the link management unit 28 resumes the link monitoring by resuming the instruction to periodically send the inquiry frame to the ONU (ONU 4). Let it resume.

  As a result, when there is no upstream traffic from the ONU, it is possible to reduce the power consumption of blocks unnecessary for upstream communication from the ONU to the OLT while maintaining the link between the ONU and the OLT. Further, since the upstream traffic generated during the transition to the low power consumption mode is accumulated in the buffer unit of the ONU and transmitted when communication is resumed, frame loss can be avoided.

  In addition, in the above operation when traffic is stopped only in the uplink, the periodic inquiry processing from the OLT to the corresponding ONU is stopped, but the periodic inquiry is performed while maintaining the link held by the link management unit. You may carry out continuously. Also in this case, the inquiry frame is periodically transmitted, and the optical receiver 44 and the frame separator 45 receive it. Then, when urgent traffic arrives in the buffer unit 41, the buffer unit 41 notifies the low consumption instruction / release unit 49 to that effect. Instructs to cancel the low power consumption mode. By doing so, the activated PON control unit 46 can receive the inquiry frame from the OLT 2 from the frame separation unit 45, and can obtain the uplink transmission permission by returning the inquiry response frame to the inquiry frame. . As a result, in the case of an emergency, the ONU 4 can leave the low power consumption mode and transmit uplink data earlier than the predetermined time expires.

(Case 1-4) When the link in the PON section is disconnected Finally, the operation when the link with the OLT 2 is disconnected will be described. In order to maintain the link between OLT2 and ONU4, exchange the inquiry frame and inquiry response frame from each other's PON control unit periodically and confirm the contents, and only when the link is maintained Perform data communication.

  When the inquiry frame is not detected for a certain period of time, the ONU 4 low-consumption block determination unit 48 cannot confirm the link. Therefore, the frame multiplexing unit 42, optical transmission, which is a block necessary for communication control with the OLT 2 is used. Only the block 43, the optical receiving unit 44, the frame separation unit 45, and the PON control unit 46 are left, and other blocks are determined to be changed to the low power consumption mode, and a notification to that effect is sent to the low consumption instruction / release unit 49 To do.

  The low-consumption instruction / release unit 49 of the ONU 4 instructs the corresponding block to transit to the low-power consumption mode until the PON link (link with the OLT 2) is restored. When the link is recovered and the inquiry frame is received from the OLT 2 via the optical receiver 44 and the frame separator 45, the low-consumption block determination unit 48 issues a transition cancellation instruction and receives the low-consumption instruction received The release unit 49 gives an instruction to activate each unit. As a result, a low power consumption effect corresponding to a state where there is no link is obtained while maintaining a state where the link with the OLT 2 can be recovered.

  As described above, in this embodiment, ONU monitors upstream traffic from ONU to OLT and reports it to OLT, and OLT monitors downstream traffic. The ONU to be changed to the power mode and the communication direction are determined and the ONU is instructed. In addition, the ONU that has received this is configured to shift the functional unit corresponding to the designated communication direction to the low power consumption mode for a certain period of time. Further, in the OLT, the link confirmation process is stopped until the predetermined time elapses, so that the link is considered not broken. Furthermore, when the link cannot be confirmed in the ONU, the other function is shifted to the low power consumption mode while maintaining the function of performing the link. As a result, it is possible to reduce power consumption in the ONU while maintaining the link between the OLT and the ONU or maintaining the linkable state.

Embodiment 2. FIG.
In the first embodiment, the OLT monitors the uplink and downlink traffic with the ONU, and the ONU monitors and reports the uplink traffic from the ONU to the OLT. In the present embodiment, a case will be described in which uplink traffic is monitored by OLT.

  FIG. 2 is a diagram illustrating a configuration example of the PON system in the present embodiment. The configuration of FIG. 2 includes an OLT 2B instead of the OLT 2 and an ONU 4B instead of the ONU 4 as compared with the configuration of FIG. The ONU 4B does not include the upstream traffic monitoring unit 47, but the OLT 2B includes the upstream traffic monitoring unit 30 instead. The upstream traffic monitoring unit 30 is provided for the purpose of monitoring upstream traffic from the ONU 4B.

  The upstream traffic monitoring unit 30 of the OLT 2B monitors user frames transferred to the higher-level device 1 via the optical reception unit 24 and the frame separation unit 25. Thus, the traffic monitoring unit 30 performs the same function as the upstream traffic monitoring unit 47 of FIG.

  Next, the operation in the PON system configured as described above will be described. Here, a case where only the upstream traffic from the ONU 4B to the OLT 2B is stopped will be described.

  The upstream traffic monitoring unit 30 of the OLT 2B monitors the user frame transferred to the higher-level device 1 via the optical reception unit 24 and the frame separation unit 25, and when no user frame is detected for a certain period, there is no upstream traffic. And notifies the low consumption determination unit 29 to that effect. Receiving this, the low consumption determination unit 29 determines to shift only the uplink direction for the corresponding ONU (ONU4B) to the low power consumption mode, and instructs the PON control unit 26 to notify the fact. The PON control unit 26 transmits, to the ONU 4B, a transition instruction frame that instructs to transition to the low power consumption mode in the uplink direction.

  In the ONU 4B, as in “Case 1-3” in the first embodiment, a process of shifting to the low power consumption mode is performed. Thereafter, as described above, when the low power consumption operating time in the ONU 4B expires, the low power consumption instruction / cancellation unit 49 of the ONU 4B instructs the low power consumption mode to be released and activates each block. On the other hand, in the OLT 2B, when the time during which the ONU 4B transitions to the low power consumption mode expires, the PON control unit 26 resumes link monitoring by resuming the periodic inquiry to the corresponding ONU (ONU 4).

  As described above, in this embodiment, the OLT monitors both upstream traffic from the ONU to the OLT and downstream traffic from the OLT to the ONU, and these monitoring results indicate that the OLT has a low power consumption mode. The ONU and the communication direction to be transferred to are determined, and the ONU is instructed. Also in this case, as in the first embodiment, it is possible to reduce the power consumption in the ONU while maintaining the link between the OLT and the ONU or maintaining the linkable state.

Embodiment 3 FIG.
In Embodiments 1 and 2, on the OLT side, ONUs that reduce power consumption and their communication directions are determined. In this embodiment, a case will be described in which whether or not to reduce power consumption and its communication direction are determined in the ONU.

  FIG. 3 is a diagram illustrating a configuration example of the PON system in the present embodiment. Compared with the configuration of FIG. 1, the configuration of FIG. 3 does not include the low consumption determination unit 29 in the OLT 2C, and includes the low consumption block determination unit 48C instead of the low consumption block determination unit 48 in the ONU 4C. The point is different. In addition to the function of the low-consumption block determination unit 48, the low-consumption block determination unit 48C has a function of determining a communication direction for reducing power consumption.

  Next, the operation in the PON system configured as described above will be described. Hereinafter, the case will be described separately based on the link state of the PON section and the uplink and downlink traffic states.

(Case 2-1) When the link in the PON section is established and there is no traffic in both uplink and downlink.
When the downstream traffic monitoring unit 27 of the OLT 2C detects that there is no downstream traffic addressed to the ONU 4C from the host device 1, it notifies the PON control unit 26 to that effect. The PON control unit 26 uses the frame multiplexing unit 22 and the optical transmission unit 23 to transmit a control frame notifying that effect (hereinafter referred to as “traffic notification frame”) to the ONU 4C.

  The ONU 4C low-consumption block determination unit 48C receives the traffic notification frame via the optical reception unit 44 and the frame separation unit 45. On the other hand, the upstream traffic monitoring unit 47 of the ONU 4C monitors the buffer unit 41 and, when detecting that there is no traffic from the TE 10 for a certain period, notifies the low-consumption block determination unit 48C to that effect. In this way, when the low-consumption block determination unit 48C receives a notification that there is no downlink traffic from the OLT 2C and no traffic from the TE 10, both uplink and downlink communication directions for the OLT 2C are received. Is determined to transition to the low power consumption mode, and the PON control unit is instructed to report to that effect to the OLT 2C. The PON control unit transmits a control frame (hereinafter referred to as a “transition declaration frame”) carrying the content (the transition to the low power consumption mode and the communication direction to be transitioned) to the OLT 2C.

  After instructing transmission of the transition declaration frame, the ONU4C low-consumption block determination unit 48C autonomously receives data from the OLT 2C and transmits data to the TE 10, and receives data from the TE 10 and transmits it to the OLT 2C. The block to be transmitted, the block necessary for communication control between the OLT 2C and the own ONU 4C, is shifted to the low power consumption mode. That is, when the frame multiplexing unit 42, the optical transmission unit 43, the optical reception unit 44, the frame separation unit 45, the PON control unit 46, the uplink traffic monitoring unit 47, and the low consumption block determination unit 48C are shifted to the low power consumption mode. And notifies the low consumption instruction / cancellation unit 49 to that effect.

  The ONU4C low-consumption instruction / cancellation unit 49, for example, designates a low-power consumption operating time that is a time determined in advance by the PON system and set in the own device, and transitions to the low-power consumption mode for the above block. Instruct to do.

  On the other hand, when the PON control unit 26 of the OLT 2C receives the transition declaration frame via the optical reception unit 24 and the frame separation unit 25, it recognizes that the ONU 4C transitions to the low power consumption mode. Further, the PON control unit 26 can expect that communication between the own device and the ONU 4C is interrupted while the ONU 4C is transitioning to the low power consumption mode. For this reason, the PON control unit 26 is determined in advance by the PON system and set in its own OLT (or specified in the transition declaration frame received from the ONU 4C so as not to break the link with the ONU 4C. The process of monitoring the link is stopped until the time elapses. That is, the periodic inquiry frame transmission to the corresponding ONU (ONU4C) is stopped, and the link state held by the link management unit 28 is maintained.

  In the meantime, in the OLT 2C, when traffic addressed to the corresponding ONU (ONU 4C) arrives from the host device 1, it is stored in the buffer unit 21.

  Similarly, in the ONU 4C, when traffic addressed to the OLT 2C arrives from the TE 10, it is stored in the buffer unit 41.

  When the low power consumption operating time expires in the ONU 4C, the low power consumption instruction / release unit 49 of the ONU 4C transmits an instruction to cancel the low power consumption mode to each of the blocks, and activates each block. Further, when the low power consumption mode operation time expires in the OLT 2C, the PON control unit 26 of the OLT 2C resumes link monitoring by resuming a periodic inquiry to the corresponding ONU (ONU 4C).

  As a result, when there is no uplink or downlink traffic in the ONU 4C, it is possible to reduce the power consumption of blocks unnecessary for communication with the OLT 2C while maintaining the link with the OLT 2C. As for the upper and lower traffic generated during the transition to the low power consumption mode, the downlink traffic is accumulated in the OLT 2C buffer unit 21 and the uplink traffic is accumulated in the ONU 4C buffer unit 41, and is transmitted / received after the low power consumption mode is released. Therefore, an effect that no frame loss occurs can be obtained.

(Case 2-2) When a link in the PON section is established and there is no downlink traffic.
Next, an operation when only downlink traffic is stopped will be described. The downstream traffic monitoring unit 27 of the OLT 2C monitors the data storage state of the buffer unit 21 and, when there is no data addressed to the ONU 4C, notifies the PON control unit 26 that there is no traffic addressed to the ONU 4C. The PON control unit 26 transmits a traffic notification frame for notifying that there is no downlink traffic to the ONU 4C to the ONU 4C via the frame multiplexing unit 22 and the optical transmission unit 23.

  When the ONU 4C low-consumption block determination unit 48C receives the traffic notification frame via the optical reception unit 44 and the frame separation unit 45 in a state where the uplink traffic monitoring unit 47 has not been notified that there is no uplink traffic, Judge that there is no downstream traffic only. In this case, the low-consumption block determination unit 48C determines that the block that receives data from the OLT 2C and transmits the data to the TE 10 and the block that is necessary for communication control with the OLT 2C are shifted to the low power consumption mode. That is, the optical receiving unit 44, the frame separating unit 45, the PON control unit 46, the upstream traffic monitoring unit 47, and the low-consumption block determining unit 48C are determined as the blocks to be shifted to the low power consumption mode, and a low-consumption instruction is given to that effect. Notify the release unit 49. Further, the PON control unit 46 is instructed to report to the OLT 2C that the transition to the low power consumption mode is made. The PON control unit 46 transmits a transition declaration frame carrying the contents to the OLT 2C.

  The ONU 4C low-consumption instruction / cancellation unit 49 receives an upstream transmission permission from the OLT 2C, which will be described later, at a time determined in advance by the PON system or at a time specified in a transition declaration frame transmitted from the own device to the OLT 2C A certain low power consumption operating time is designated, and the corresponding block is instructed to transition to the low power consumption mode.

  When receiving the transition declaration frame, the PON control unit 26 of the OLT 2C recognizes that the ONU 4C transitions to the low power consumption mode. The OLT 2C can be expected to interrupt communication with the ONU 4C while the ONU 4C is transitioning to the low power consumption mode. For this reason, the PON control unit 26 is set in advance in the PON system and set in its own OLT (or in a transition declaration frame received from the ONU 4C so as not to break the link with the ONU 4C. The process of monitoring the link, that is, the process of periodically sending an inquiry frame to the corresponding ONU (ONU 4C) is stopped until the elapsed time) elapses.

  By the way, in the ONU 4C, the ONU 4C cannot transmit an inquiry response frame even if uplink data is generated by switching the block relating to downlink traffic and the block relating to exchange of control information with the OLT 2C to the low power consumption mode. The transmission permission cannot be obtained. Accordingly, the PON control unit 26 of the OLT 2C transmits future uplink transmission permission to the ONU 4C using the statistical information and the minimum bandwidth guarantee information held so far according to the low power consumption operating time and the like. . The ONU 4C low-consumption block determination unit 48C instructs the low-consumption instruction / cancellation unit 49 to transition to the low-power consumption mode as soon as the upstream transmission permission is received via the optical reception unit 44 and the frame separation unit 45. .

  Further, while the ONU 4C is transitioning to the low power consumption mode, the OLT 2C stores the traffic addressed to the corresponding ONU (ONU 4C) from the host device 1 in the buffer unit 21.

  When the low power consumption operation time in the ONU 4C expires, the low power consumption instruction / release unit 49 of the ONU 4C instructs the blocks to release the low power consumption mode and activates the blocks. On the other hand, when the ONU 4C transitions to the low power consumption mode expires, the PON control unit 26 of the OLT 2C resumes link monitoring by resuming transmission of a regular inquiry frame to the corresponding ONU (ONU 4C). .

  Thereby, when there is no downstream traffic, the same effect as in the first embodiment can be obtained.

(Case 2-3) When the link in the PON section is established and there is no uplink traffic only.
Next, the operation when only the upstream traffic is stopped will be described. The upstream traffic monitoring unit 47 of the ONU 4C monitors the data accumulation amount in the buffer unit 41, detects that there is no upstream data when the upstream data from the TE 10 does not exist for a certain period of time, and reduces the low-consumption block determination unit 48C. To that effect. The low-consumption block determination unit 48C determines that there is no uplink traffic when it is not notified that there is no downlink traffic by the traffic notification frame from the OLT 2C, and when the notification is received. Therefore, the low-consumption block determination unit 48C determines to shift the uplink direction for the OLT 2C to the low power consumption mode, and instructs the PON control unit 46 to transmit a transition declaration frame notifying that effect. Upon receiving this, the PON control unit 46 transmits a transition declaration frame to the OLT 2C via the optical reception unit 44 and the frame separation unit 45.

  Also, the ONU 4C low-consumption block determination unit 48C transmits data from the TE 10 to the OLT 2C over a low power consumption operating time that is a predetermined time or a time described in the transition declaration frame transmitted to the OLT 2C. It is determined that a block and a block necessary for communication control with the OLT 2C are to be changed. That is, the frame multiplexing unit 42, the optical transmission unit 43, the PON control unit 46, the uplink traffic monitoring unit 47, and the low-consumption block determination unit 48C are determined as blocks to be shifted to the low power consumption mode, and a low-consumption instruction is given to that effect. Notify the release unit 49.

  The low power consumption instruction / cancellation unit 49 designates the low power consumption operating time to the corresponding block and instructs to shift to the low power consumption mode.

  When receiving the transition declaration frame, the PON control unit 26 of the OLT 2C recognizes that the ONU 4C transitions to the low power consumption mode. Further, the PON control unit 26 can expect that communication between the own device and the ONU 4C is interrupted while the ONU 4C is transitioning to the low power consumption mode. For this reason, the PON control unit 26 is determined in advance by the PON system and set in its own OLT (or specified in the transition declaration frame received from the ONU 4C so as not to break the link with the ONU 4C. The process of monitoring the link is stopped until the time elapses. That is, the periodic inquiry frame transmission to the corresponding ONU (ONU4C) is stopped, and the link state held by the link management unit 28 is maintained.

  When traffic from the TE 10 to the OLT 2C arrives at the ONU 4C until the low power consumption operating time elapses, the buffer unit 41 accumulates data. When the low power consumption operating time expires, the ONU 4C low consumption instruction / cancellation unit 49 instructs each block to cancel the low power consumption mode, and activates each block. On the other hand, when the time during which the ONU 4C transitions to the low power consumption mode expires in the OLT 2C, the PON control unit 26 resumes link monitoring by resuming periodic inquiry frame transmission to the corresponding ONU (ONU 4C). .

  Thereby, when there is no upstream traffic from the ONU, the same effect as in the first embodiment can be obtained.

  In the operation when the traffic is stopped only in the above-described case, the periodic inquiry processing from the OLT to the corresponding ONU is stopped. However, the link management unit 28 continues the periodic inquiry while maintaining the link. May be implemented. The specific operation is the same as described above.

(Case 2-4) When the link in the PON section is disconnected Finally, the operation when the link with the OLT 2C is disconnected will be described. As described above, between the OLT 2C and the ONU 4C, in order to maintain the link, the inquiry frame and the inquiry response frame are periodically exchanged between the PON control units of each other, the contents are confirmed, and the link is maintained. Data communication is performed only when

  The ONU 4C low-consumption block determination unit 48C is a block required for communication control with the OLT 2C when the inquiry frame is not detected for a certain period of time. The frame multiplexing unit 42, the optical transmission unit 43, and the optical reception unit 44, only the frame separation unit 45 and the PON control unit 46 are left, and another block is determined as a block to be shifted to the low power consumption mode, and the fact is notified to the low consumption instruction / cancellation unit 49.

  The low consumption instruction / cancellation unit 49 instructs the corresponding block to shift to the low power consumption mode until the PON link (link with the OLT 2C) is restored. When the link is recovered and the inquiry frame is received from the OLT 2C via the optical receiver 44 and the frame separator 45, the ONU 4C low-consumption block determination unit 48C instructs the low-consumption instruction / release unit 49 to cancel. Receiving this, the low consumption instruction / cancellation unit 49 issues a transition cancellation instruction to each block and activates each unit.

  Thereby, even when the link with the OLT 2C is broken, the same effect as in the first embodiment can be obtained.

  As described above, in this embodiment, ONU monitors the upstream traffic from ONU to OLT, and OLT monitors the downstream traffic from OLT to ONU. The communication direction and the block to be changed to the power mode are determined. Also in this case, as in the first and second embodiments, it is possible to reduce the power consumption in the ONU while maintaining the link between the OLT and the ONU or maintaining the linkable state. .

Embodiment 4 FIG.
In the third embodiment, the downstream traffic with the ONU is monitored in the OLT. In the present embodiment, a case where downstream traffic is monitored by ONU will be described.

  FIG. 4 is a diagram illustrating a configuration example of the PON system in the present embodiment. Compared with the configuration of FIG. 3, the configuration of FIG. 4 includes an OLT 2D instead of the OLT 2C, and an ONU 4D instead of the ONU 4C. The OLT 2D does not include the downlink traffic monitoring unit 27, and instead, the ONU 4D includes the downlink traffic monitoring unit 50. The downstream traffic monitoring unit 50 is provided for the purpose of monitoring upstream traffic from the OLT 2D.

  The downlink traffic monitoring unit 50 of the OLT 4D monitors user frames transmitted to the TE 10 via the optical reception unit 44 and the frame separation unit 45. As a result, the downstream traffic monitoring unit 50 performs the same function as the downstream traffic monitoring unit 27 of FIG.

  Next, the operation in the PON system configured as described above will be described. Here, a case where only the downlink traffic from the OLT 2D to the ONU 4D is stopped will be described as an example.

  The downstream traffic monitoring unit 50 of the ONU 4D monitors a user frame transmitted to the TE 10 via the optical reception unit 44 and the frame separation unit 45, and determines that there is no downstream traffic when no user frame is detected for a certain period. This is notified to the low-consumption block determination unit 48C. Receiving this, the low-consumption block determination unit 48C determines to shift only the uplink direction for the OLT 2D to the low-power consumption mode, and instructs the PON control unit 26 to notify that. The PON control 26 transmits to OLT 2D a transition declaration frame that declares a transition to the low power consumption mode in the uplink direction.

  In the ONU 4D, as in “Case 2-3” in the third embodiment, a process of shifting to the low power consumption mode is performed. Thereafter, when the low power consumption operation time in the ONU 4D expires, the low power consumption instruction / cancellation unit 49 of the ONU 4D instructs the cancellation of the low power consumption mode and activates each block, as described above. On the other hand, in the OLT 2D, when the time during which the ONU 4D transitions to the low power consumption mode has expired, the PON control unit 26 resumes link monitoring by resuming transmission of a regular inquiry frame to the corresponding ONU (ONU 4). Let

  As described above, in this embodiment, the ONU monitors both upstream traffic from the ONU to the OLT and downstream traffic from the OLT to the ONU. Based on these monitoring results, the low power consumption mode in the ONU is determined. The communication direction and the block to be shifted to are determined. Also in this case, similarly to the third embodiment, it is possible to reduce the power consumption in the ONU while maintaining the link between the OLT and the ONU or maintaining the linkable state.

  As described above, the PON system according to the present invention is useful for a PON system that provides a service that requires real-time performance, and is particularly suitable for maintaining a link even when data communication is not performed.

1 Host device 2, 2B, 2C, 2D OLT
3 Splitter 4, 4B, 4C, 4D ONU
10 TE
DESCRIPTION OF SYMBOLS 21 Buffer part 22 Frame multiplexing part 23 Optical transmission part 24 Optical receiving part 25 Frame separation part 26 PON control part 27 Downstream traffic monitoring part 28 Link management part 29 Low consumption determination part 30 Upstream traffic monitoring part 41 Buffer part 42 Frame multiplexing part 43 Optical Transmitter 44 Optical Receiver 45 Frame Separator 46 PON Controller 47 Up Traffic Monitoring Unit 48, 48C Low Consumption Block Determination Unit 49 Low Consumption Instruction / Release Unit 50 Down Traffic Monitoring Unit

Claims (9)

Is connected via a subscriber-side communication device and the optical fiber, the subscriber-side communication device PON having a control unit for controlling the state of the link between the (Passive Optical Network) Oite the station-side communication device for the system,
The controller is
A first low power consumption mode in which an operation mode of uplink communication of the subscriber side communication device is changed to a low power consumption state and an operation mode of downlink communication is not changed to a low power consumption state; and the subscriber side communication of the second low-power mode to transition the device operation mode and the operation mode of the downlink communication of the uplink communication to the low power consumption state, it generates a control signal which is either a low power consumption mode is designated,
The generated pre-SL control signal transmitted to the subscriber-side communication device,
When been pre SL system the subscriber communication device based on a low power consumption mode specified in control signal transmitted from the control unit is operating in the first or second power saving mode, the station station side communication apparatus characterized by inhibiting the cleavage of the link between the side communication device and the subscriber-side communication device. Station-side communication device and connected through an optical fiber PON (Passive Optical Network) Oite subscriber side communication device for the system,
The subscriber side communication device is:
First low power consumption mode which does not transition the operation mode of the subscriber-side communication apparatus upstream operation mode is allowed downstream communication transition to the low power consumption state of the communication to the low power consumption state, and, the subscriber-side communication of the devices upstream communication operation mode and the second power saving mode to the operation mode of the downlink communication to transition to the low power consumption state of said station side control signal is either a low power consumption mode is designated Received from the communication device,
Transition to the first or second low power consumption mode based on the low power consumption mode specified in the received control signal,
The subscriber-side communication device after transitioning to the first or second low power consumption mode,
In a state in which the said subscriber communication device and the station-side communication apparatus is maintained linked together, the subscriber-side communication apparatus, characterized by an operation by the first or second power saving mode . Includes a station-side communication instrumentation 置及 beauty subscriber side communication equipment in a communication system for performing communication in a state where between the station-side communication device and the subscriber-side communication devices are linked,
The station side communication device is:
A first low power consumption mode in which an operation mode of uplink communication of the subscriber side communication device is changed to a low power consumption state and an operation mode of downlink communication is not changed to a low power consumption state; and the subscriber side communication A control signal for generating a control signal in which any one of the low power consumption modes is designated among the second low power consumption modes for transitioning the operation mode of the uplink communication and the operation mode of the downlink communication to the low power consumption state . 1 control unit ;
Transmission means for transmitting the control signal generated by the first control unit to the subscriber side communication device ,
The subscriber side communication device is:
Receiving means for receiving the control signal transmitted from the station side communication device ;
A second control unit that performs transition to the first or second low power consumption mode based on the low power consumption mode specified in the control signal received by the receiving unit;
The first control unit provided in the station side communication device, when the subscriber side communication device that has transitioned to the first or second low power consumption mode is operating in the low power consumption mode, A communication system, characterized in that disconnection of a link between the station side communication device and the subscriber side communication device is suppressed. It includes a station-side communication instrumentation 置及 beauty subscriber side communication equipment, a communication method of a communication system for performing communication in a state where between the station-side communication device and the subscriber-side communication devices are linked,
A first low power consumption mode in which the station side communication device does not change the uplink communication operation mode of the subscriber side communication device to the low power consumption state and does not change the downlink communication operation mode to the low power consumption state; and One of the low power consumption modes is designated out of the second low power consumption mode for transitioning the uplink communication operation mode and the downlink communication operation mode of the subscriber side communication device to the low power consumption state. A first step of generating a control signal;
Said control signal generated by the first step and a second step of transmitting the station side communication apparatus to the subscriber-side communication device,
A third step in which the subscriber side communication device receives the control signal transmitted in the second step;
A fourth step in which the subscriber-side communication device transitions to the first or second low power consumption mode based on the low power consumption mode specified in the control signal received in the third step; ,
When the subscriber-side communication device that has transitioned to the first or second low power consumption mode in the fourth step is operating in the first or second low power consumption mode, the subscriber side A fifth step of suppressing disconnection of the link between the communication device and the station-side communication device ;
A communication method comprising: In the station side communication device of the PON (Passive Optical Network) system connected to the subscriber side communication device via an optical fiber,
  Of the uplink communication and the downlink communication of the subscriber side communication device, a control signal carrying a communication direction for transition to a low power consumption state is transmitted to the subscriber side communication device, and the transmitted control A control unit that suppresses disconnection of a link with the subscriber-side communication device when the subscriber-side communication device is operating in a low power consumption state based on a communication direction carried in a signal;
  A station side communication device characterized by the above. In the communication device on the subscriber side of the PON (Passive Optical Network) system connected to the communication device on the station side via an optical fiber,
  Of the uplink communication and the downlink communication of the subscriber side communication device, a control signal carrying a communication direction for transition to a low power consumption state is transmitted to the station side communication device, and the subscriber side communication device and the station A control unit that transitions the operation mode in the communication direction that transitions to the low power consumption state to the low power consumption state while the link with the side communication device is maintained
  A subscriber-side communication device. A control device in a station side communication device of a PON (Passive Optical Network) system connected to a subscriber side communication device via an optical fiber,
  Of the uplink communication and the downlink communication of the subscriber side communication device, a control signal carrying a communication direction for transition to a low power consumption state is transmitted to the subscriber side communication device, and the transmitted control signal is transmitted to the subscriber side communication device. Suppressing disconnection of a link with the subscriber side communication device when the subscriber side communication device is operating in a low power consumption state based on the placed communication direction.
  A control device characterized by. A control device in a subscriber side communication device of a PON (Passive Optical Network) system connected to a station side communication device via an optical fiber,
  Of the uplink communication and the downlink communication of the subscriber side communication device, a control signal carrying a communication direction for transition to a low power consumption state is transmitted to the station side communication device, and the subscriber side communication device and the station The communication mode operation mode transiting to the low power consumption state is changed to the low power consumption state while the link with the side communication device is maintained.
  A control device characterized by. In a communication method of a communication system comprising a station side communication device and a subscriber side communication device, and performing communication in a state where the station side communication device and the subscriber side communication device are linked,
  The subscriber-side communication device transmits a control signal carrying a communication direction for transitioning to a low power consumption state among the uplink communication and the downlink communication of the subscriber-side communication device to the station-side communication device; ,
  The subscriber side communication device transitioning the operation mode of the communication direction carried in the control signal to a low power consumption state;
  Suppressing the disconnection of the link between the subscriber-side communication device and the station-side communication device when the subscriber-side communication device is operating in a low power consumption state;
  A communication method comprising:

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