JP7420284B2 - Optical communication control device, optical communication control method, and optical communication control program - Google Patents

Description

The present invention relates to a technique for saving power in a PON (Passive Optical Network) system.

In the field of communication systems, it is common to have a redundant configuration. For example, a communication path between a first L2SW (level 2 switch device) to which a user terminal is connected and a second L2SW connected to an external network is a path connected by a PON system, and a communication path connected by an Ethernet (registered trademark). A configuration is adopted in which redundancy is provided for the route connected to the terminal (for example, see Non-Patent Document 1). In this example, an ONU (Optical Network Unit) constituting the PON system is connected to a first L2SW, and an OLT (Optical Line Terminal) is connected to a second L2SW. Then, if the user terminal traffic can be transmitted via Ethernet, the server controls the first L2SW and the second L2SW to stop communication via the PON, which puts the ONU into a sleep state and saves power on the network. is realized (for example, see Non-Patent Documents 2 and 3).

A. E. Ankouri et al. , “Real-time Assessment of PtP/PtMP Fixed Access Serving RAN with MEC Capabilities,” M2H1.1, 2020. N. McKeown et al. , “OpenFlow: enabling innovation in campus networks,” ACM SIGCOMM Computer Communication Review, 2008. Ujikawa et al., “Efforts to save power in optical access communication equipment,” NTT Technology Journal, 2015.1.

However, in the conventional technology, as described in FIG. 6 of Non-Patent Document 3, for example, the ONU needs to be activated intermittently at regular intervals in order to communicate the PON control signal with the OLT. For this reason, even when ONU traffic is distributed to Ethernet, the PON-related portion of the ONU cannot be completely put into a sleep state, which poses a problem in reducing the power consumption of the ONU.

In this way, in order to achieve further power savings for ONUs, it is necessary to allocate ONU traffic to Ethernet and then completely shut down the PON-related parts of the ONU without starting them until PON bandwidth is needed. Control is required to put the ONU into a sleep state and activate the PON-related parts of the ONU when the PON band is needed.

In view of the above problems, the present invention provides an optical communication control device, an optical communication control method, and an optical communication control program that can further reduce the power consumption of ONUs that constitute a PON system arranged on redundant paths. The purpose is to provide

The present invention provides a first path in which a first communication device and a second communication device are connected by an ONU and an OLT that constitute a PON system, and a first path arranged in parallel with the first path. In the optical communication control device that performs power saving control of a communication system with redundant routes, the optical communication control device includes a monitoring unit that monitors a traffic amount between the ONU and the OLT, and a sleep mode in which the traffic amount is predetermined. a process of transmitting a distribution command for distributing traffic from the first route to the second route to the first communication device and the second communication device when the traffic is smaller than a threshold for maintaining the link between the ONUs; The present invention is characterized by comprising a command unit that performs processing of transmitting a link maintenance command to the OLT to perform a link maintenance command to the OLT, and processing of transmitting a sleep command to the ONU to cause the ONU to enter a sleep state.

Further, the present invention provides a first path in which a first communication device and a second communication device are connected by an ONU and an OLT that constitute a PON system, and a first path is arranged in parallel with the first path. An optical communication control method that performs power saving control of a communication system that is made redundant with a second path, the method comprising: a monitoring process of monitoring a traffic amount between the ONU and the OLT; a process of transmitting, to the first communication device and the second communication device, a distribution command for distributing traffic from the first path to the second path when the threshold value is smaller than a predetermined sleep threshold; and the ONU The present invention is characterized by executing command processing for transmitting a link maintenance command to the OLT to maintain the link, and transmitting a sleep command to the ONU for transitioning the ONU to a sleep state.

Further, the optical communication control program of the present invention is characterized in that the processing performed by the optical communication control method is executed by a computer.

The optical communication control device, the optical communication control method, and the optical communication control program according to the present invention can further reduce the power consumption of ONUs forming a PON system arranged on redundant paths.

1 is a diagram showing an example of the overall configuration of a communication system according to the present embodiment. FIG. 2 is a diagram illustrating a configuration example of an OLT. It is a diagram showing an example of the configuration of an ONU. It is a diagram showing an example of the configuration of a server. FIG. 3 is a diagram illustrating an example of server control processing. FIG. 3 is a diagram illustrating a comparative example of conventional sleep control and sleep control used in this embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an optical communication control device, an optical communication control method, and an optical communication control program according to the present invention will be described with reference to the drawings.

FIG. 1 shows an example of the overall configuration of a communication system 100 according to this embodiment. The communication system 100 includes a first path 151 in which the communication path between the L2SW 101 (1) and the L2SW 101 (2) is connected by the PON system 102, and an Ethernet (registered trademark) arranged in parallel with the first path 151. ) and a second route 152 connected thereto for redundancy. Here, L2SW101(1) corresponds to the first communication device, and L2SW101(2) corresponds to the second communication device.

A user terminal 103 is connected to the L2SW 101 (1), an external NW (NetWork) 104 is connected to the L2SW 101 (2), and the user terminal 103 is connected to the external network via a first path 151 or a second path 152. NW 104 can be accessed.

Furthermore, a server 105 for monitoring and controlling the operation of the communication system 100 is connected to the L2SW 101(2).

The server 105 controls the operation of the PON system 102 via the L2SW 101(2) and L2SW 101(1). In particular, the server 105 functions as an optical communication control device that performs power saving control of the communication system 100. Note that the detailed configuration of the server 105 will be described later.

The PON system 102 includes an OLT 201, an ONU 202, and a splitter 203.

The OLT 201 is connected to the L2SW 101 (2) through an SNI (Service Node Interface). The OLT 201 is connected to a plurality of ONUs 202 via a splitter 203. For example, downlink optical signals from the OLT 201 to the plurality of ONUs 202 are time-division multiplexed and transmitted to each ONU 202. Further, upstream optical signals from the plurality of ONUs 202 to the OLT 201 are time-division multiplexed so as not to collide at the transmission timing given to each ONU 202 from the OLT 201. For this purpose, the OLT 201 allocates a communication band (data transmission timing, possible transmission time, etc.) to each ONU 202 in response to a band request from each ONU 202 . Note that the detailed configuration of the OLT 201 will be described later.

The ONU 202 is connected to the L2SW 101(1) through a UNI (User Network Interface). Here, the ONU 202 is one of the plurality of ONUs 202. The ONU 202 stores data input from the UNI in an internal buffer, transmits a bandwidth request to the OLT 201 based on the amount of data stored in the buffer, and is allocated a communication bandwidth from the OLT 201. Further, the ONU 202 has a function of going into a sleep state when there is no data to communicate in order to save power. Note that the detailed configuration of the ONU 202 will be described later.

The splitter 203 is composed of a passive element that branches or combines optical signals, and has the function of branching the downstream optical signal transmitted from the OLT 201 to multiple ONUs 202 and the function of combining the upstream optical signals transmitted from the multiple ONUs 202. It also has the function of outputting to the OLT 201 side. Note that the wavelengths of the upstream optical signal and the downstream optical signal are different.

As described above, in the communication system 100 according to the present embodiment, the communication path between the L2SW 101(1) and the L2SW 101(2) is connected to the first path 151 connected by the PON system 102 and the Ethernet (registered trademark). It is assumed that the connected second path 152 is redundant. In the optical communication control method according to the present embodiment, the server 105 monitors the traffic volume of the ONU 202 of the PON system 102, and when the traffic volume is smaller than a predetermined threshold value, the server 105 issues an instruction to put the ONU 202 into a sleep state. and sends a command to L2SW 101(1) and L2SW 101(2) to distribute data communication from the first path 151 to the second path 152 of the PON system 102.

In addition, when the ONU 202 is in a sleep state in which it is not activated intermittently, the server 105 determines that the amount of data traffic that should originally be transmitted on the first route 151, which is distributed to the second route 152, is lower than a predetermined threshold. If the size is large, a command is sent to make the ONU 202 active, and the data that should originally have been communicated via the first route 151 is distributed to the second route 152 and communicated between the ONU 202 and OLT 201 that have become active. A distribution command for distribution back to the first path 151 between the ONUs 202 is sent to the ONU 202.

Here, in the following explanation, when a common explanation is given to L2SW101(1) and L2SW101(2), the number at the end of the reference code is omitted and the term L2SW101 is written.

FIG. 2 shows a configuration example of the OLT 201. In FIG. 2, the OLT 201 includes an optical transceiver 301, a PON_LSI 302, a PHY 303, and a link control unit 304.

The optical transceiver 301 includes a laser element, a light receiving element, a modulation/demodulation circuit, and the like, and transmits and receives optical signals to and from the ONU 202 via the PON side splitter 203.

The PON_LSI 302 is a dedicated LSI equipped with functions for creating frames and controlling communication in accordance with the PON standard, and has functions for allocating communication bands and controlling links with a plurality of ONUs 202.

The PHY 303 has a function of connecting with the upper L2SW 101 at the physical layer using SNI, and transmits and receives data between the L2SW 101 and the L2SW 101 . In the example of FIG. 1, the PHY 303 receives a link maintenance command sent from the server 105 via the L2SW 101(2).

In addition to the normal PON standard-compliant function of disconnecting the link connection of an ONU 202 that does not receive a control signal for a certain period of time, the link control unit 304 has the function of disconnecting the link connection of an ONU 202 that does not receive a control signal for a certain period of time. It has a function of controlling the link connection of the ONU 202 so as not to disconnect it even when a control signal is not received. Note that the command from the server 105 may be received via the PHY 303 or the PON_LSI 302.

In this way, the OLT 201 according to this embodiment can control the ONU 202.

FIG. 3 shows a configuration example of the ONU 202. In FIG. 3, the ONU 202 includes an optical transceiver 401, a PON_LSI (Large Scale Integration) 402, a PHY 403, and a sleep unit 404.

The optical transceiver 401 includes a laser element, a light receiving element, a modulation/demodulation circuit, and the like, and transmits and receives optical signals to and from the OLT 201 via the splitter 203 on the PON side.

The PON_LSI 402 is composed of a dedicated LSI equipped with functions for creating frames and controlling communications in accordance with the PON standard. It has functions such as keep-alive access.

The PHY 403 has a function of connecting with the lower L2SW 101 at the physical layer through the UNI, and transmits and receives data between the L2SW 101 and the L2SW 101 . In the example of FIG. 1, it is connected to the user terminal 103 via the L2SW 101(1), and receives instructions sent from the server 105 via the L2SW 101(2) and L2SW 101(1). Note that commands from the server 105 are received via the PHY 403. Thereby, even if parts related to the PON, such as the optical transceiver 401 and the PON_LSI 402, are in a completely sleep state, they can receive a startup command from the server 105.

The sleep unit 404 has a normal sleep function compliant with the PON standard that puts the optical transceiver 401 and PON_LSI 402 into a sleep state when there is no communication data. However, the normal sleep function needs to be activated intermittently in order to maintain the link state with the OLT 201 and check the presence or absence of communication data. Therefore, the ONU 202 according to the present embodiment includes a sleep control unit 405 in the sleep unit 404 to realize a sleep function that does not require intermittently activation in addition to the normal sleep function.

The sleep control unit 405 has a function of receiving a sleep command from the server 105, and in response to the sleep command from the server 105, puts the optical transceiver 401 and the PON_LSI 402 into a sleep state in which they are not activated intermittently.

Further, when the sleep control unit 405 receives a command to start the server 105 from the UNI side in a sleep state in which intermittent startup is not performed, the sleep control unit 405 starts up from the sleep state and shifts to an active state. Note that in the sleep state, circuits and functions related to the PON side do not operate, but circuits and functions that receive a command to start the server 105 from the UNI side operate.

In this way, the ONU 202 according to the present embodiment realizes sleep control that does not perform intermittent activation according to the command from the server 105, so that the ONU 202 is further This enables lower power consumption.

FIG. 4 shows an example of the configuration of the server 105. In FIG. 4, the server 105 includes an L2SW monitoring section 501, an instruction section 502, and an L2SW control section 503. Here, the server 105 may be configured with a computer that executes the processing performed in each block using a pre-stored program.

The L2SW monitoring unit 501 performs processing for monitoring information (bandwidth information, etc.) for each flow in the L2SW 101 (monitoring processing). In the example of FIG. 1, the L2SW monitoring unit 501 can monitor the traffic amount of the ONU 202 via the L2SW 101(1). Similarly, the L2SW monitoring unit 501 can monitor the amount of traffic from the OLT 201 to each ONU 202 via the L2SW 101(2). That is, the L2SW monitoring unit 501 can monitor the traffic amount of uplink communication from ONU 202 to OLT 201 and the amount of traffic of downlink communication from OLT 201 to ONU 202.

The command unit 502 performs processing for transmitting various commands to the link control unit 304 of the OLT 201, the sleep control unit 405 of the ONU 202, and the L2SW control unit 503 within the own device (server 105) (command processing). Specifically, the instruction unit 502 performs a process of comparing the traffic volume of the ONU 202 monitored by the L2SW monitoring unit 501 with at least one preset threshold, and when a predetermined condition is met, puts the ONU 202 into a sleep state. A sleep command is sent from the L2SW control unit 503 to the ONU 202 to cause the ONU 202 to perform a sleep command.

The command unit 502 then transmits a link maintenance command to the OLT 201 in order to maintain the link state of the ONU 202 that has transmitted the sleep command. Further, the command unit 502 transmits to the L2SW 101 a distribution command for distributing data communicated between the ONU 202 and the OLT 201, which cannot communicate due to the sleep command, to the second path 152.

Further, when the amount of data traffic that should originally be transmitted on the first route 151 distributed to the second route 152 no longer satisfies a predetermined condition, the instruction unit 502 causes the ONU 202 in the sleep state to enter the active state. The L2SW control unit 503 sends a startup command to the ONU 202. Then, the command unit 502 transfers the data that should originally have been communicated via the first route 151 to the second route 152 to the first route 151 between the ONU 202 and the OLT 201 that have become active. A distribution command for redistribution is transmitted to the ONU 202.

The L2SW control unit 503 controls the transmission method (transmission port, etc.) for each communication flow in the L2SW 101. In particular, in this embodiment, the L2SW control unit 503 transmits the commands output from the command unit 502 to the OLT 201 and ONU 202 as, for example, an Ethernet frame.

In this way, the server 105 can perform sleep control of the ONU 202 based on the traffic volume of the ONU 202 connected via the L2SW 101.

In particular, the server 105 according to this embodiment sends a link maintenance command to the OLT 201 facing the ONU 202 that has entered the sleep state, so even if the ONU 202 enters the sleep state for a long time, the link with the OLT 201 will not be disconnected. Communication can be performed immediately after the ONU 202 is started.

Further, since the server 105 according to the present embodiment distributes the communication of the ONU 202 in the sleep state to the redundant route, the communication of the user terminal 103 is not affected.

FIG. 5 shows an example of control processing of the server 105. Note that the process in FIG. 5 is a process that is mainly performed on the server 105 side in cooperation with the various units described in FIGS. 1 to 4. Here, when the server 105 is implemented by a computer, a program (optical communication control program) for executing the process shown in FIG. 5 is stored in advance in a storage medium such as a memory.

In step S101, the command unit 502 of the server 105 determines whether the traffic volume (first traffic volume) directed to the ONU 202 monitored by the L2SW monitoring unit 501 is smaller than a first threshold value set in advance (determination 1). If the result of determination 1 is Yes, the process proceeds to step S102, and if the result is No, the process of step S101 is repeated.
Traffic for ONU < 1st threshold...(Judgment 1)

In step S102, the command unit 502 of the server 105 determines whether the amount of traffic transmitted from the ONU 202 monitored by the L2SW monitoring unit 501 (second traffic amount) is smaller than a second threshold set in advance. (Judgment 2). If the result of determination 2 is Yes, the process proceeds to step S103, and if No, the process returns to step S101. Here, the first threshold value and the second threshold value correspond to the sleep threshold value, and may be set to the same value or may be set to different values.
ONU transmission traffic < 2nd threshold...(Judgment 2)

In step S103, the command unit 502 of the server 105 transmits a traffic distribution command to the L2SW 101 to distribute the traffic on the first path 151 of the PON system 102 to the second path 152 of Ethernet. Then, the command unit 502 transmits a link maintenance command that causes the OLT 201 to maintain the link of the ONU 202. Further, the command unit 502 transmits a sleep command to the ONU 202 to put the ONU 202 into a sleep state.

In step S104, the command unit 502 of the server 105 determines whether the traffic volume (third traffic volume) directed to the ONU 202 monitored by the L2SW monitoring unit 501 is larger than a preset third threshold (determination 3). If the result of determination 3 is Yes, the process proceeds to step S106, and if the result is No, the process proceeds to step S105. Note that the third threshold is greater than or equal to the first threshold.
Traffic for ONU > 3rd threshold...(Judgment 3)

In step S105, the command unit 502 of the server 105 determines whether the amount of traffic transmitted from the ONU 202 monitored by the L2SW monitoring unit 501 (fourth traffic amount) is larger than a fourth threshold set in advance. (Judgment 4). If the result of determination 4 is Yes, the process proceeds to step S106, and if No, the process returns to step S104. Note that the fourth threshold is greater than or equal to the second threshold. Further, the third threshold value and the fourth threshold value correspond to the activation threshold value, and may be set to the same value or may be set to different values.
ONU transmission traffic>4th threshold...(Judgment 4)

In step S106, the command unit 502 of the server 105 transmits a startup command to the ONU 202 to start the ONU 202 from the sleep state.

In step S107, the command unit 502 of the server 105 transfers the traffic that should originally be communicated in the PON system 102, which was distributed to the second Ethernet route 152 when the ONU 202 is in the sleep state, to the first route of the PON system 102. 151 is sent to the L2SW 101.

Note that the first threshold, the second threshold, the third threshold, and the fourth threshold can be set separately. Further, each threshold value may be set, for example, to a proportion (for example, 90%) of the communication band of the second path 152 of Ethernet, or may be set to a proportion (for example, 10%, etc.) of the ONU 202 band. . Alternatively, the threshold value may be changed depending on the communication status of a plurality of redundant routes. For example, if the total traffic volume of the plurality of redundant routes is large, the threshold value is increased, and if the total traffic volume is low, the threshold value is decreased.

In this way, in the communication system 100 according to the present embodiment, the server 105 monitors the traffic volume of the ONU 202, puts the ONU 202 into a sleep state based on the traffic volume of the ONU 202, and makes the traffic of the PON system redundant. Since the ONU 202 does not need to be activated intermittently, it is possible to save more power than in the past. In particular, since the OLT 201 maintains the link of the ONU 202 in the sleep state, it is possible to keep the ONU 202 in the sleep state for a longer time than the link of the ONU 202 is disconnected.

Next, sleep control in the communication system 100 according to this embodiment and conventional sleep control will be compared.

The ONU 202 according to the present embodiment has conventional sleep control (referred to as first sleep control) that requires intermittent activation even during sleep, and sleep control that does not require intermittent activation used in this embodiment. (referred to as second sleep control).

FIG. 6 shows a comparative example of conventional sleep control and sleep control used in this embodiment. In FIG. 6, the horizontal axis indicates time.

In FIG. 6, in the conventional first sleep control, when the state changes from the active state to the sleep state, it is necessary to activate the device intermittently at predetermined time intervals to control the presence or absence of transmitted/received data and maintain the link. There is. For this reason, the ONU 202 intermittently activates the optical transceiver 401 and the PON_LSI 402 to make them active, resulting in increased power consumption.

On the other hand, in the second sleep control performed by the ONU 202 according to the present embodiment, when the active state changes to the sleep state due to a sleep command from the server 105, the sleep state is maintained until a startup command is received from the server 105. .

In this way, the ONU 202 according to the present embodiment has a second sleep control that can maintain the sleep state without intermittently starting up, in addition to the conventional first sleep control that needs to be started intermittently. . When used as the ONU 202 of a PON system 102 placed on a redundant path, the second sleep control enables significant power savings compared to the conventional first sleep control. Become. Note that when the ONU 202 is not arranged on a redundant path, the ONU 202 can save power by using the conventional first sleep control.

As described above, the optical communication control device, the optical communication control method, and the optical communication control program according to the present invention can further reduce the power consumption of ONUs that constitute a PON system arranged on redundant paths. can be achieved.

100... Communication system; 101... L2SW; 102... PON system; 103... User terminal; 104... External NW; 105... Server; 201... OLT; 202... ONU; 203... Splitter; 301... Optical transceiver; 302... PON_LSI; 303... PHY; 304... Link control unit; 401... Optical transceiver; 402... PON_LSI; 403... ...PHY;404...Sleep section;405...Sleep control section;501...L2SW monitoring section;502...Instruction section;503...L2SW control section

Claims (7)

A first path in which a first communication device and a second communication device are connected by an ONU and an OLT that constitute a PON system, and a second path arranged in parallel with the first path. In optical communication control equipment that performs power-saving control of redundant communication systems,
a monitoring unit that monitors the amount of traffic between the ONU and the OLT;
If the traffic amount is smaller than a predetermined sleep threshold, a distribution command for distributing traffic from the first route to the second route is transmitted to the first communication device and the second communication device. a command unit that performs processing, processing for transmitting a link maintenance command to the OLT to maintain the link of the ONU, and processing for transmitting a sleep command for shifting the ONU to a sleep state to the ONU. Features of optical communication control device. The optical communication control device according to claim 1,
The monitoring unit monitors an amount of traffic that should originally be communicated between the ONU and the OLT and is distributed to the second route when the ONU is in a sleep state;
The command unit includes processing for transmitting to the ONU an activation command for transitioning the ONU to an active state when the distributed traffic amount is larger than a predetermined activation threshold, and distribution to the second path. An optical communication control device, comprising: transmitting a distribution command to the first communication device and the second communication device for distributing the traffic that has been sent back to the first path. The optical communication control device according to claim 2,
The optical communication control device, wherein the sleep threshold and the activation threshold are set at a predetermined ratio to the communication band of the redundant second route. A first path in which a first communication device and a second communication device are connected by an ONU and an OLT that constitute a PON system, and a second path arranged in parallel with the first path. An optical communication control method for power saving control of a redundant communication system, the method comprising:
monitoring processing for monitoring the amount of traffic between the ONU and the OLT;
If the traffic amount is smaller than a predetermined sleep threshold, a distribution command for distributing traffic from the first route to the second route is transmitted to the first communication device and the second communication device. and a process of transmitting a link maintenance command to the OLT to maintain the link of the ONU, and a process of transmitting a sleep command to the ONU to transition the ONU to a sleep state. An optical communication control method characterized by: The optical communication control method according to claim 4,
In the monitoring process, when the ONU is in a sleep state, the amount of traffic that should originally be communicated between the ONU and the OLT and that is distributed to the second route is monitored;
In the command processing, if the distributed traffic amount is larger than a predetermined activation threshold, a process of transmitting a activation command to the ONU to shift the ONU to an active state, and distribution to the second path. An optical communication control method comprising the step of: transmitting a distribution command to the first communication device and the second communication device for distributing the traffic that had been sent back to the first path. The optical communication control method according to claim 5,
The optical communication control method, wherein the sleep threshold and the activation threshold are set at a predetermined ratio to a communication band of the redundant second route. An optical communication control program, characterized in that a computer executes the processing performed by the optical communication control method according to any one of claims 4 to 6.

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