WO2022113167A1

WO2022113167A1 - Optical communication control device, optical communication control method, and optical communication control program

Info

Publication number: WO2022113167A1
Application number: PCT/JP2020/043652
Authority: WO
Inventors: 貴充栩野; 裕隆氏川; 慈仁酒井
Original assignee: 日本電信電話株式会社
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2022-06-02
Also published as: JP7420284B2; JPWO2022113167A1

Abstract

This optical communication control device performs energy-efficient control of a communication system in which a first communication device and a second communication device art redundantly connected by a first path, which is connected to an ONU and an OLT, and a second path, and comprises: a monitoring unit which monitors the amount of traffic between the ONU and the OLT, and a command unit which, if the amount of traffic is less than a predetermined sleep threshold, performs processing for transmitting to the first communication device and the second communication device an allocation command for allocating traffic from the first path to the second path, processing for transmitting a link hold command to the OLT, and processing for transmitting a sleep command to the ONU. By this means, it is possible for the ONU to save energy.

Description

Optical communication control device, optical communication control method, and optical communication control program

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 connected by a PON system, and an Ethernet®. It is configured to be redundant with the route connected by (see, for example, Non-Patent Document 1). In this example, the ONU (Optical Netowork Unit) constituting the PON system is connected to the first L2SW, and the OLT (Optical Line Terminal) is connected to the second L2SW. When the traffic of the user terminal can be transmitted via Ethernet, the server controls the first L2SW and the second L2SW to stop the communication via the PON, so that the ONU goes to sleep and the network power is saved. (See, for example, Non-Patent Documents 2 and 3).

However, in the prior art, for example, as described in FIG. 6 of Non-Patent Document 3, the ONU needs to be intermittently activated at regular intervals in order to communicate the PON control signal with the OLT. Therefore, even when the ONU traffic is distributed to Ethernet, the part related to the ONU PON cannot be completely put into sleep state, and there is a problem in power saving of the ONU.

In this way, in order to realize further power saving of the ONU, after the ONU traffic is distributed to the Ethernet, the part related to the PON of the ONU is completely not activated until the bandwidth of the PON is required. It is necessary to control to activate the part related to the PON of the ONU when the PON band is required in the sleep state.

In view of the above problems, the present invention presents an optical communication control device, an optical communication control method, and an optical communication control program capable of further power saving of the ONU constituting the PON system arranged in the redundant path. The purpose is to provide.

In the present invention, a first path in which a first communication device and a second communication device are connected by an ONU and an OLT constituting a PON system, and a first path arranged in parallel with the first path. In an optical communication control device that performs power saving control of a communication system redundant with two routes, a monitoring unit that monitors the traffic amount between the ONU and the OLT, and a sleep in which the traffic amount is predetermined. When the value is smaller than the threshold value, the 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 and the ONU link are maintained. It is characterized by having a process of transmitting a link maintenance command to be performed to the OLT and a process of transmitting a sleep command to shift the ONU to a sleep state to the ONU.

Further, in the present invention, the first communication device and the second communication device are arranged in parallel with the first path connected by the ONU and the OLT constituting the PON system and the first path. It is an optical communication control method that performs power saving control of a communication system redundant with a second route, and is a monitoring process for monitoring the traffic amount between the ONU and the OLT, and 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 sleep threshold is smaller than the determined sleep threshold, and the ONU. It is characterized by executing a process of transmitting a link maintenance command for maintaining the link of the above to the OLT, a process of transmitting a sleep command for shifting the ONU to a sleep state to the ONU, and an instruction process for performing the process.

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 the ONU constituting the PON system arranged in the redundant path.

It is a figure which shows the whole structure example of the communication system which concerns on this embodiment. It is a figure which shows the structural example of OLT. It is a figure which shows the structural example of ONU. It is a figure which shows the configuration example of a server. It is a figure which shows an example of the control process of a server. It is a figure which shows the comparative example of the conventional sleep control and the sleep control used in this embodiment.

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

FIG. 1 shows an overall configuration example of the communication system 100 according to the present embodiment. The communication system 100 is an Ethernet® arranged in parallel with a first path 151 in which a communication path between L2SW101 (1) and L2SW101 (2) is connected by a PON system 102 and a first path 151. ) Is made redundant with the second path 152 connected by. Here, the L2SW101 (1) corresponds to the first communication device, and the L2SW101 (2) corresponds to the second communication device.

A user terminal 103 is connected to the L2SW101 (1), an external NW (NetWork) 104 is connected to the L2SW101 (2), and the user terminal 103 is externally connected via the first route 151 or the second route 152. You can access NW104.

Further, a server 105 for monitoring and controlling the operation of the communication system 100 is connected to the L2SW101 (2).

The server 105 controls the operation of the PON system 102 via L2SW101 (2) and L2SW101 (1). In particular, the server 105 functions as an optical communication control device that controls the power saving of the communication system 100. The detailed configuration of the server 105 will be described later.

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

OLT201 is connected to L2SW101 (2) by SNI (Service Node Interface). The OLT 201 is connected to a plurality of ONU 202 via a splitter 203. For example, the downlink optical signal from the OLT 201 to the plurality of ONU 202s is time-division-multiplexed and transmitted to each ONU 202. Further, the upstream optical signals from the plurality of ONU202s to the OLT201 are time-division-multiplexed so as not to collide with each other at the transmission timing given from the OLT201 to the respective ONU202s. For this purpose, the OLT 201 allocates a communication band (data transmission timing, transmittable time, etc.) to each ONU 202 in response to a band request from each ONU 202. The detailed configuration of OLT201 will be described later.

ONU202 is connected to L2SW101 (1) by UNI (User Network Interface). Here, the ONU202 is one of a plurality of ONU202s. The ONU 202 stores data input from the UNI in an internal buffer, transmits a band request to the OLT 201 according to the amount of data stored in the buffer, and allocates a communication band from the OLT 201. Further, the ONU 202 has a function of going to sleep when there is no data to be communicated in order to save power. The detailed configuration of ONU202 will be described later.

The splitter 203 is composed of a passive element that branches or synthesizes an optical signal, and combines a function of branching a downlink optical signal transmitted from the OLT 201 into a plurality of ONU 202 and an upstream optical signal transmitted from the plurality of ONU 202. It has a function to output to the OLT201 side. 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 L2SW101 (1) and L2SW101 (2) is connected by the PON system 102 with the first path 151 and Ethernet (registered trademark). It is assumed that it is redundant with the second path 152 to be connected. Then, 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 puts the ONU 202 into a sleep state. Is transmitted, and an instruction for distributing data communication from the first path 151 to the second path 152 of the PON system 102 is transmitted to the L2SW101 (1) and the L2SW101 (2).

Further, in the sleep state in which the ONU 202 is not started intermittently, the server 105 determines that the amount of data traffic that should be originally transmitted by the first route 151 distributed to the second route 152 is from a predetermined threshold value. When the size is large, a command to activate ONU202 is transmitted, and the data that should be communicated on the first path 151, which was originally distributed to the second path 152 and communicated, is transferred to the ONU202 and OLT201 in the active state. A distribution command for distributing back to the first path 151 between them is transmitted to ONU202.

Here, in the following description, when the description common to L2SW101 (1) and L2SW101 (2) is given, the (number) at the end of the code is omitted and described as L2SW101.

FIG. 2 shows a configuration example of OLT201. In FIG. 2, the OLT 201 has an optical transceiver 301, a PON_LSI 302, a PHY 303, and a link control unit 304.

The optical transceiver 301 is composed of a laser element, a light receiving element, a modulation / demodulation circuit, and the like, and transmits and receives an optical signal to and from the ONU 202 via the splitter 203 on the PON side.

The PON_LSI302 is composed of a dedicated LSI equipped with a function of creating a frame conforming to the PON standard and controlling communication, and has a function of allocating a communication band and controlling a link with a plurality of ONU202s.

The PHY 303 has a function of connecting to the upper L2SW101 by a physical layer by SNI, and transmits and receives data to and from the L2SW101. In the example of FIG. 1, the PHY 303 receives a link maintenance instruction transmitted from the server 105 via the L2SW101 (2).

In addition to the function conforming to the normal PON standard that disconnects the link connection of the ONU 202 that does not receive the control signal for a certain period of time, the link control unit 304 in the present embodiment receives a link maintenance command from the server 105 for a certain period of time from the ONU 202. It has a function to control so that the link connection of ONU202 is not disconnected even when the control signal is not received. The command from the server 105 may be received via the PHY 303 or the PON_LSI 302.

In this way, the OLT201 according to the present embodiment can control the ONU202.

FIG. 3 shows a configuration example of ONU202. In FIG. 3, the ONU 202 has an optical transceiver 401, a PON_LSI (Large Scale Integration) 402, a PHY 403, and a sleep unit 404.

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

The PON_LSI402 is composed of a dedicated LSI equipped with a function of creating a frame conforming to the PON standard and controlling communication, and periodically OLT201 to request and allocate a communication band with the OLT201 and maintain a link. It has a function to perform keep-alive etc. to access.

The PHY403 has a function of connecting to the lower L2SW101 by a physical layer by UNI, and transmits and receives data to and from the L2SW101. In the example of FIG. 1, the user terminal 103 is connected to the user terminal 103 via the L2SW101 (1), and an instruction transmitted from the server 105 is received via the L2SW101 (2) and the L2SW101 (1). The command from the server 105 is received via the PHY 403. As a result, the start command from the server 105 can be received even when the parts related to the PON such as the optical transceiver 401 and the PON_LSI 402 are completely in the sleep state.

The sleep unit 404 has a normal sleep function compliant with the PON standard that puts the optical transceiver 401 and the PON_LSI 402 into a sleep state when there is no communication data. However, in the normal sleep function, it is necessary to intermittently activate the sleep function in order to maintain the link state with the OLT 201 and confirm the presence / absence of communication data. Therefore, the ONU 202 according to the present embodiment is provided with a sleep control unit 405 in the sleep unit 404 to realize a sleep function that does not need to be started intermittently 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 puts the optical transceiver 401 and the PON_LSI 402 into a sleep state without intermittent activation by the sleep command from the server 105.

Further, the sleep control unit 405 wakes up from the sleep state and shifts to the active state when the start command of the server 105 is received from the UNI side in the sleep state in which the sleep control unit 405 does not start intermittently. In the sleep state, the circuits and functions related to the PON side do not operate, but the circuits and functions that receive the start command of the server 105 from the UNI side are operating.

In this way, the ONU 202 according to the present embodiment realizes sleep control that does not start intermittently by the command of the server 105, so that the ONU 202 is further compared with the conventional sleep function that starts intermittently. Low power consumption is possible.

FIG. 4 shows a configuration example of the server 105. In FIG. 4, the server 105 has an L2SW monitoring unit 501, a command unit 502, and an L2SW control unit 503. Here, the server 105 may be configured by a computer that executes the processing performed in each block by a program stored in advance.

The L2SW monitoring unit 501 performs a process of monitoring information (bandwidth information, etc.) for each flow in the L2SW 101 (monitoring process). In the example of FIG. 1, the L2SW monitoring unit 501 can monitor the traffic volume of the ONU 202 via the L2SW101 (1). Similarly, the L2SW monitoring unit 501 can monitor the amount of traffic from the OLT 201 to each ONU 202 via the L2SW101 (2). That is, the L2SW monitoring unit 501 can monitor the traffic volume of uplink communication from ONU202 to OLT201 and the traffic volume of downlink communication from OLT201 to ONU202, respectively.

The command unit 502 performs a process of 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 in the own device (server 105) (command processing). Specifically, the command unit 502 performs a process of comparing the traffic amount of the ONU 202 monitored by the L2SW monitoring unit 501 with at least one preset threshold value, and puts the ONU 202 into a sleep state when a predetermined condition is satisfied. A sleep command is transmitted from the L2SW control unit 503 to the ONU 202.

Then, the instruction unit 502 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 the data communicated between the ONU 202 and the OLT 201, which cannot be communicated due to the sleep command, to the second path 152.

Further, when the traffic volume of the data originally to be transmitted on the first route 151 distributed to the second route 152 does not satisfy the predetermined condition, the command unit 502 activates the ONU 202 in the sleep state. The start command for this is transmitted from the L2SW control unit 503 to the ONU202. Then, the command unit 502 transfers the data to be communicated on the first path 151, which was originally distributed to the second path 152, to the first path 151 between the ONU 202 and the OLT 201 in the active state. A distribution command for distributing back is transmitted to ONU202.

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

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

In particular, since the server 105 according to the present embodiment transmits a link maintenance command to the OLT 201 facing the ONU 202 in the sleep state, the link with the OLT 201 is not disconnected even when the ONU 202 is in the sleep state for a long time. Communication can be performed immediately after the ONU202 is activated.

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 the control process of the server 105. The process of FIG. 5 is a process mainly performed on the server 105 side in cooperation with each part described with reference to FIGS. 1 to 4. Here, when the server 105 is realized by a computer, a program (optical communication control program) for executing the process of 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 or not the traffic amount (first traffic amount) for the ONU 202 monitored by the L2SW monitoring unit 501 is smaller than the preset first threshold value (determination). 1). If the result of the 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 or not the traffic amount (second traffic amount) transmitted from the ONU 202 monitored by the L2SW monitoring unit 501 is smaller than the preset second threshold value. (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 <second threshold value ... (judgment 2)

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

In step S104, the command unit 502 of the server 105 determines whether or not the traffic amount (third traffic amount) for the ONU 202 monitored by the L2SW monitoring unit 501 is larger than the preset third threshold value (determination). 3). If the result of the determination 3 is Yes, the process proceeds to step S106, and if the result is No, the process proceeds to step S105. The third threshold value is equal to or higher than the first threshold value.
Traffic for ONU> 3rd threshold ... (Judgment 3)

In step S105, the command unit 502 of the server 105 determines whether or not the traffic amount (fourth traffic amount) transmitted from the ONU 202 monitored by the L2SW monitoring unit 501 is larger than the preset fourth threshold value. (Judgment 4). If the result of the determination 4 is Yes, the process proceeds to step S106, and if No, the process returns to step S104. The fourth threshold value is equal to or higher than the second threshold value. 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 instruction unit 502 of the server 105 transmits an activation command for activating the ONU 202 from the sleep state to the ONU 202.

In step S107, the command unit 502 of the server 105 transfers the traffic originally to be communicated by the PON system 102, which was distributed to the second route 152 of the Ethernet when the ONU 202 is in the sleep state, into the first route of the PON system 102. A traffic distribution command for distributing back to 151 is transmitted to L2SW101.

The first threshold value, the second threshold value, the third threshold value, and the fourth threshold value can be set separately. Further, each threshold value may be set to, for example, a ratio (for example, 90%) to the communication band of the second route 152 of Ethernet, or may be set to a ratio (for example, 10%) to the band of ONU202. .. Alternatively, the threshold value may be changed according to the communication status of the 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 small, the threshold value is decreased.

As described above, 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 is distributed to the Ethernet route, it is not necessary to start the ONU 202 intermittently, and power saving can be achieved as compared with the conventional case. In particular, since the OLT 201 maintains the ONU202 link in the sleep state, the ONU202 link can be put to sleep longer than the time when the link is disconnected.

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

The ONU 202 according to the present embodiment has a conventional sleep control (referred to as a first sleep control) that needs to be activated intermittently even during sleep, and a sleep control that does not require intermittent activation used in the present embodiment. It has two functions (referred to as a second sleep control).

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

In FIG. 6, in the conventional first sleep control, when the active state is changed to the sleep state, it is necessary to intermittently wake up at predetermined time intervals to control the presence / absence of transmitted / received data and maintain the link. There is. Therefore, the ONU 202 intermittently activates the optical transceiver 401 and the PON_LSI 402 to activate them, resulting in high power consumption.

On the other hand, in the second sleep control performed by ONU202 according to the present embodiment, when the sleep state is changed from the active state by the sleep command from the server 105, the sleep state is maintained until the start command is received from the server 105. ..

As described above, the ONU 202 according to the present embodiment has a second sleep control capable of maintaining a sleep state without intermittent activation, in addition to the conventional first sleep control that needs to be activated intermittently. .. When used as the ONU202 of the PON system 102 arranged in the redundant path, the second sleep control enables significant power saving as compared with the conventional first sleep control. Become. When the ONU202 is not arranged in the redundant path, the ONU202 can save power by 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 further reduce the power consumption of the ONU constituting the PON system arranged in the redundant path. Can be planned.

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 unit; 405 ... sleep control unit; 501 ... L2SW monitoring unit; 502 ... command unit; 503 ... L2SW control unit

Claims

A first path in which the first communication device and the second communication device are connected by an ONU and an OLT constituting a PON system, and a second path arranged in parallel with the first path. In an optical communication control device that controls power saving of a communication system that is redundant in
A monitoring unit that monitors the amount of traffic between the ONU and the OLT,
When the traffic amount is smaller than the predetermined sleep threshold value, 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. It has a command unit for performing a process, a process of transmitting a link maintenance command for maintaining the link of the ONU to the OLT, and a process of transmitting a sleep command for shifting the ONU to the sleep state to the ONU. A featured optical communication control device.
In the optical communication control device according to claim 1,
When the ONU is in the sleep state, the monitoring unit monitors the amount of traffic that should originally be communicated between the ONU and the OLT and is distributed to the second route.
When the distributed traffic amount is larger than the predetermined activation threshold value, the command unit transmits an activation command for shifting the ONU to the active state to the ONU, and distributes the ONU to the second route. An optical communication control device characterized by performing a process of transmitting a distribution command for distributing the traffic to the first route back to the first communication device and the second communication device.
In the optical communication control device according to claim 2,
An optical communication control device, wherein the sleep threshold value and the activation threshold value are set at a predetermined ratio with respect to the redundant communication band of the second path.
A first path in which the first communication device and the second communication device are connected by an ONU and an OLT constituting a PON system, and a second path arranged in parallel with the first path. It is an optical communication control method that controls the power saving of a redundant communication system.
A monitoring process for monitoring the amount of traffic between the ONU and the OLT, and
When the traffic amount is smaller than the predetermined sleep threshold value, 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. Processing, a process of transmitting a link maintenance command for maintaining the link of the ONU to the OLT, a process of transmitting a sleep command for shifting the ONU to the sleep state to the ONU, and an instruction process for performing the processing are executed. An optical communication control method characterized by.
In the optical communication control method according to claim 4,
In the monitoring process, when the ONU is in the sleep state, the amount of traffic that should originally be communicated between the ONU and the OLT and is distributed to the second route is monitored.
In the instruction processing, when the distributed traffic amount is larger than the predetermined activation threshold value, the processing of transmitting the activation command for shifting the ONU to the active state to the ONU and the distribution to the second route. An optical communication control method comprising performing a process of transmitting a distribution command for distributing the traffic to the first route back to the first communication device and the second communication device.
In the optical communication control method according to claim 5,
An optical communication control method, wherein the sleep threshold value and the activation threshold value are set at a predetermined ratio with respect to the redundant communication band of the second path.
An optical communication control program characterized in that a computer executes a process performed by the optical communication control method according to any one of claims 4 to 6.