JP5158613B2 - PON system, OLT device, communication speed switching method and program in PON system - Google Patents

Description

  The present invention relates to a communication speed switching method and program in a PON system, an OLT device, an ONU device, and a PON system, and in particular, supports two communication methods with different communication speeds, and efficiently switches between the communication methods. PON system that enables

  As the Internet, particularly the Internet based on a high-speed communication standard such as FTTH (Fiber To The Home) spreads to general households and general enterprises, higher speed and larger capacity communication is required even with the same FTTH.

  As a technology for realizing higher-speed and larger-capacity communication, an optical passive component such as a coupler is inserted in the middle of an optical fiber line to branch an optical signal, and the branched optical signal is drawn into a subscriber's home (PON There is a technology called Passive Optical Network. Using this technology, Ethernet (registered trademark) data frames (hereinafter simply referred to as “frames”) are transmitted and received as they are from the subscriber to the switching center. The G-EPON (Gigabit Ethernet Passive Optical Network, GE-PON) Standardized (IEEE802.3ah).

  This G-EPON eliminates the overhead (delay) that occurs when converting a frame to another format, and makes it possible to provide an Internet connection service with a maximum communication speed of 1 Gbps (Gigabit per minute) to ordinary households. However, a standard (IEEE802.3av) called 10G-EPON (10 Gigabit Ethernet Passive Optical Network), which has been improved to improve the communication speed to 10 Gbps, has been developed.

  G-EPON and 10G-EPON can share the same device and optical fiber line except for the different communication speeds. Between 10G-EPON and G-EPON, simply change the settings of each device. The communication method can be switched with. For this reason, a PON system has been developed that supports both 10G-EPON and G-EPON systems and can switch the communication speed between 10 Gbps and 1 Gbps.

  FIG. 10 is an explanatory diagram showing a configuration of an existing PON system 901 compatible with both 10G-EPON and G-EPON communication systems. In the PON system 901, an OLT (Optical Line Terminal) device 910 which is a device on the operator side and one or a plurality of ONU (Optical Network Unit) devices 920 which are devices on the subscriber side are connected via an optical cable 930. And connected by P2MP (Point to MultiPoint).

  The OLT device 910 is connected to a host device on the operator side, and the ONU device 920 is connected to a terminal device on the subscriber side. In the PON system 901, communication from the OLT device 910 to the ONU device 920 is called down, and conversely, communication from the ONU device 920 to the OLT device 910 is called up.

  In FIG. 10, the middle of the optical cable 930 is branched by a coupler 931, so that three ONU devices 920a, 920b, and 920c are connected, but this number is within the allowable range of the OLT device 910. But you can. The configurations of the ONU devices 920a, 920b, and 920c are all the same, and are collectively referred to as the ONU device 920.

  The OLT device 910 and the ONU device 920 can be connected using one of the communication standards of 10G-EPON which is uplink and downlink 10 Gbps communication and G-EPON which is uplink and downlink 1 Gbps communication. Here, the same optical cable 930 is used for 10G-EPON and G-EPON. However, different optical cables may be used for 10G-EPON and G-EPON.

  The OLT device 910 transmits and receives an optical signal via an optical cable 930, multiplexes 1 Gbps and 10 Gbps optical signals, converts an optical signal and an electrical signal, and an electrical transmission / reception unit 911 between the optical transmission / reception unit 911. A SERDES (SERDES, Serialzer / Deserialzer) unit 912 that transmits and receives signals and converts serial signals and parallel signals to each other, and a PON termination unit 913 that transmits and receives parallel signals to and terminates the PON line with the cerdes unit 912. Prepare.

  The PON termination unit 913 transmits and receives parallel signals to and from the cerdes unit 912, terminates the PON line, and an MPCP (Multi Point Control Protocol) unit 913a; and a path switching unit 913b that distributes and aggregates frames transmitted to and received from the MPCP unit 913a; Is provided.

  The OLT device 910 further transmits / receives a frame to / from the path switching unit 913b and temporarily stores the frame, and transmits / receives a frame to / from the frame buffer unit 914 to perform network transmission / reception with a host device. And an SNI (Service Node Interface) termination unit 915.

  One ONU device 920 includes an optical transmission / reception unit 921 that transmits / receives an optical signal via the optical cable 930, a sardice unit 922 that transmits / receives an electrical signal to / from the optical transmission / reception unit 921, and converts a serial signal and a parallel signal; It includes a PON termination unit 923 that transmits and receives parallel signals to and from the sades unit 922 and terminates the PON line.

  The optical transmission / reception unit 921 is an optical division unit 921a that performs wavelength division and aggregation of 1 Gbps and 10 Gbps optical signals, and a 1G optical / electrical conversion unit that transmits and receives 1 Gbps optical signals to and from the optical division unit 921a and converts optical signals and electrical signals. 921b, and a 10G optical / electrical conversion unit 921c that transmits and receives a 10 Gbps optical signal and converts an optical signal and an electrical signal with the optical dividing unit 921a.

  The Sardes unit 922 transmits / receives electrical signals to / from the 1G optical / electrical converter 921b to convert serial signals and parallel signals, and 1G optical / electrical converter 921c transmits / receives electrical signals to / from the serial signals. A 10G cerdes 922b for converting parallel signals.

  The PON terminator 923 includes an MPCP unit 923a that transmits and receives parallel signals to and from the 1G cerdes 922a and 922b and terminates the PON line, and a path switching unit 923b that distributes and aggregates frames transmitted to and received from the MPCP 923a. Is provided.

  The ONU device 920 further transmits / receives a frame to / from the path switching unit 923b and temporarily stores the frame, and transmits / receives a frame to / from the frame buffer unit 924 to establish a network line with the terminal device. And a UNI (User Network Interface) terminating unit 925 that terminates.

  When communication is performed using G-EPON for the section from the light splitting unit 921a to the route switching unit 923b, the route of the 1G optical / electrical conversion unit 21b to 1G cerdes 922a to MPCP unit 923a is used. On the other hand, when communication is performed using 10G-EPON, the route of the 1G optical / electrical conversion unit 921c to 10G cerdes 922b to MPCP 923a is used.

  The MPCP unit 913a of the OLT device 910 can switch the communication method between 10G-EPON and G-EPON by a control signal from the connected external device 940. Similarly, the MPCP unit 923a of the ONU device 920 can also switch the communication method between 10G-EPON and G-EPON by a control signal from the connected external device 941.

  In this connection, there are the following technical documents. Among them, Patent Document 1 describes a technique for stopping or reducing the power consumption of circuits related to communication in a PON system capable of communicating at a communication speed of 1G and 10G when 10G downlink communication is not used. Has been. Japanese Patent Application Laid-Open No. 2004-260260 describes a technique that enables an ONU device to select an appropriate circuit corresponding to a communication speed in a PON system in which different communication speeds are mixed in the upstream direction. Patent Document 3 and Patent Document 4 describe an OLT device and an ONU device that measure the “flow rate or flow rate acceleration” of data and stop the operation of the circuit related to the communication speed that is not used according to this. Yes.

JP 2009-027538 A JP 2009-188775 A JP 2009-296231 A JP 2009-296234 A

  The OLT device 910 and the ONU device 920 of the PON system 901 shown in FIG. 10 described above consume much more power when operating with 10G-EPON than when operating with G-EPON. To increase. Even in high-speed communication, it is naturally necessary to reduce power consumption as a social requirement, so in the PON system 901, reduction of power consumption is a major issue.

  Since the PON system 901 can switch the communication method between 10G-EPON and G-EPON, in order to reduce power consumption, when the communication capacity of the entire system is small and the line is not congested, G- It is desirable to use 10G-EPON communication only when communication is performed using EPON and the communication capacity increases and the line is congested.

  However, the OLT device 910 and the ONU device 920 can switch the communication method only by a control signal from the connected external device 940 or 941. It is impossible for either the OLT device 910 or the ONU device 920 to detect the communication speed and switch the communication method between the 10G-EPON and the G-EPON accordingly. In addition, since this switching is not performed in real time in accordance with the communication speed, there is a time zone in which the communication speed for each user decreases during the switching.

  Furthermore, neither the OLT device 910 nor the ONU device 920 can stop the operation of the circuit on the G-EPON side while operating in the 10G-EPON, for example. Similarly, the operation of the 10G-EPON side circuit cannot be stopped while operating in the G-EPON. Therefore, even if the communication method is switched between 10G-EPON and G-EPON, power consumption is not reduced.

  Techniques that can solve this problem are not described in the aforementioned Patent Documents 1 to 4. The technique of “selecting an appropriate circuit corresponding to the communication speed” described in Patent Document 2 is applicable only in the uplink direction in which data of a plurality of ONU devices is transmitted in a time division manner. Cannot be applied in the downlink direction in which the data of the above are transmitted at different wavelengths. Therefore, this is combined with the technique of “stopping the operation of a circuit related to this communication when 10G communication is not used” described in Patent Document 1, and “1G communication is selected when the communication speed is low, and 10G communication is selected. It is impossible to make a technology that “stops the operation of the circuit”.

  In addition, as described in Patent Documents 3 to 4, “the inflow speed or inflow acceleration is measured and the circuit operation relating to the communication speed that is not used is stopped according to this” is measured. “Inflow acceleration” is different from “communication speed”. Therefore, this cannot be used as means for detecting the communication speed by the technique of Patent Document 1 or Patent Document 2.

  Therefore, it is difficult to combine all the techniques described in Patent Documents 1 to 4, and even if they can be combined, the technique cannot solve the above problems.

  An object of the present invention is to provide a communication speed switching method and program in a PON system, an OLT device, an ONU device, and a PON system that reduce power consumption and enable efficient high-speed communication.

In order to achieve the above object, a PON system according to the present invention includes an OLT (Optical Line Terminal) device, which is a communication device on the operator side, connected to one end of an optical fiber line, and light inserted in the middle of the optical fiber line. It comprises an ONU (Optical Network Unit) device that is a plurality of subscriber side communication devices connected to the other end of the optical fiber line branched by the passive component, and the OLT device and the corresponding ONU device are the first. A PON (Passive Optical Network) system configured to be able to communicate with each other at a communication speed or a second communication speed higher than the first communication speed, and the OLT device includes first and second communications. A first path switching unit that switches between communication speeds, and a first MPCP that detects a free bandwidth of a communication path of a first communication speed between the OLT device and each ONU device ( Multi Point Control Protocol) section and MPCP section determine whether or not the free bandwidth detected is sufficient, and when the free bandwidth is not enough, the ONU device having the highest bandwidth occupancy is identified, and this identified ONU And a first path switching control unit that instructs the MPCP unit to switch to the second communication speed of communication with the apparatus, and switches to the second communication speed during communication at the first communication speed. The first path switching unit has a function of switching the communication path to the second communication speed, and the first switching instruction OAM frame for the ONU device in which the first MPCP unit is specified. It has the function to transmit.

In order to achieve the above object, an OLT device according to the present invention is connected to an ONU (Optical Network Unit) device which is a plurality of subscriber side communication devices connected to an optical fiber line branched by an optical passive component, Business side communication that constructs a PON (Passive Optical Network) system configured to be able to communicate with each ONU device at a first communication speed or a second communication speed higher than the first communication speed. An OLT (Optical Line Terminal) device that is a device, a path switching unit that switches between communication at a first communication speed and a second communication speed, and first communication between the OLT device and each ONU device It judged that MPCP (Multi Point Control Protocol) unit for detecting a free band of the velocity of the communication path, whether available bandwidth MPCP unit detects is sufficient bandwidth if the spare bandwidth is not sufficient Yes ratio identifies the highest ONU apparatus, switching to a second communication speed of the communication between the identified ONU device and having a path switch control unit which instructs the MPCP unit, a first communication When the switching to the second communication speed is instructed during the communication at the speed, the path switching unit has a function of switching the communication path to the second communication speed, and the MPCP unit is identified The first switching instruction OAM frame is transmitted.

In order to achieve the above object, a communication speed switching method according to the present invention is connected to the other end of an optical fiber line branched by an OLT (Optical Line Terminal) device and an optical passive component inserted in the middle of the optical fiber line. A plurality of subscriber-side communication devices, ONU (Optical Network Unit) devices, and the OLT device and the corresponding ONU device are faster than the first communication speed or the first communication speed. In a PON (Passive Optical Network) system configured to be able to communicate with each other at a communication speed, a first communication speed between the OLT device and each ONU device during communication at the first communication speed. The first MPCP (Multi Point Control Protocol) unit of the OLT device detects the free bandwidth of the communication path, and the first route switching control unit of the OLT device determines whether or not the free bandwidth detected by the MPCP unit is sufficient. Cross, and a second communication communication between with the first path switching control unit of the OLT device to specify the highest ONU device bandwidth occupancy if the spare bandwidth is not sufficient, and this specified ONU device The first MPCP unit of the OLT device is instructed to switch to the speed, and in response to the switching instruction to the second communication speed, the first MPCP unit of the OLT device is identified with respect to the identified ONU device. The switching instruction OAM frame is transmitted, and the first path switching unit of the OLT apparatus switches the communication path from the first communication speed to the second communication speed, and the second of the ONU apparatus is communicating during the communication at the first communication speed. When the MPCP unit detects an OAM frame from the OLT device and the second MPCP unit of the ONU device detects a first switching instruction OAM frame from the OLT device, the second path switching control of the ONU device is performed. The control unit emits a control signal for switching the communication path from the first communication speed to the second communication speed, and a control signal for starting power supply to a circuit operating at the second communication speed. In response, the second path switching unit of the ONU device switches the communication path to the second communication speed, and the operation control unit of the ONU device stops supplying power to the circuit operating at the first communication speed. It is characterized by.

In order to achieve the above object, a communication speed switching program according to the present invention is inserted into an OLT (Optical Line Terminal) device, which is an operator side communication device connected to one end of an optical fiber line, and in the middle of the optical fiber line. And an ONU (Optical Network Unit) device that is a plurality of subscriber side communication devices connected to the other end of the optical fiber line branched by the optical passive component. The OLT device and the corresponding ONU device are the first ones. In a PON (Passive Optical Network) system configured to be able to communicate with each other at a communication speed of 1 or a second communication speed higher than the first communication speed, the computer included in the OLT device includes a first The procedure for detecting the free bandwidth of the communication path of the first communication speed between the OLT device and each ONU device during the communication at the communication speed of, the free bandwidth detected by the MPCP unit is sufficient A procedure for determining whether or not there is an ONU device having the highest bandwidth occupancy when the available bandwidth is not sufficient, and switching to the second communication speed for communication with the specified ONU device First switching is performed for the ONU device specified in the MPCP unit of the OLT device in accordance with a procedure for instructing the MPCP (Multi Point Control Protocol) unit provided in advance in the OLT device and a switching instruction to the second communication speed The instruction OAM frame is transmitted, and the route switching control unit of the OLT device is caused to execute a procedure for switching the communication path from the first communication speed to the second communication speed.

  Since the present invention is configured to detect the free bandwidth of the communication path as described above and switch from the first communication speed to the second communication speed when the free bandwidth is not sufficient, the G is used only when necessary. By switching from -EPON to 10G-EPON, it becomes possible to stop the operation of unused circuits. Accordingly, it is possible to provide a communication speed switching method and program in a PON system, an OLT device, an ONU device, and a PON system that can reduce power consumption and perform efficient high-speed communication.

It is explanatory drawing shown about the structure of the PON system which concerns on this invention. 2 is a flowchart illustrating an operation of switching a communication speed on the OLT device side in the PON system illustrated in FIG. 1. 3 is a flowchart showing an operation of switching communication speed on the ONU device side in the PON system 1 shown in FIG. It is a graph which shows about the mode of switching of the communication system from G-EPON shown in FIG. 2 and FIG. 3 to 10G-EPON, or 10G-EPON to G-EPON. FIGS. 4A and 4B show the states of the downlink and uplink, respectively, when switching from G-EPON to 10G-EPON. FIGS. 4C and 4D show the states of the downlink and uplink, respectively, when switching from 10G-EPON to G-EPON. It is explanatory drawing shown about the structure of the PON system which concerns on the expansion of 1st Embodiment. It is explanatory drawing shown about the structure of the PON system which concerns on the 2nd Embodiment of this invention. 7 is a flowchart showing an operation of switching communication speed on the OLT device side in the PON system shown in FIG. 6. 7 is a flowchart illustrating an operation of switching a communication speed on the ONU device side in the PON system illustrated in FIG. 6. It is explanatory drawing shown about the structure of the PON system which concerns on the expansion of 2nd Embodiment. It is explanatory drawing shown about the structure of the existing PON system corresponding to both 10G-EPON and G-EPON communication systems.

(First embodiment)
Hereinafter, the structure of the 1st Embodiment of this invention is demonstrated based on attached FIG.
First, the basic content of the present embodiment will be described, and then more specific content will be described.
The PON system 1 according to the present embodiment includes an OLT (Optical Line Terminal) device 10 that is an operator side communication device connected to one end of an optical fiber line (optical cable 30), and light inserted in the middle of the optical fiber line. It comprises an ONU (Optical Network Unit) device 20 which is a plurality of subscriber side communication devices connected to the other end of an optical fiber line branched by a passive component (coupler 31), and includes an OLT device 10 and each ONU device. Reference numeral 20 denotes a PON (Passive Optical Network) system configured to be able to communicate with each other at a first communication speed (1 Gbps) or a second communication speed (10 Gbps) higher than the first communication speed. The OLT device 10 has a path switching unit 13b that switches between performing communication at the first and second communication speeds, and a free bandwidth of the communication path of the first communication speed between the OLT device and each ONU device. MPCP (Multi Point Control Protocol) unit 13a to be detected and whether or not the free bandwidth detected by the MPCP unit is sufficient are determined, and if the free bandwidth is not sufficient, the MPCP unit is switched to the second communication speed. A route switching control unit 16a for instructing. Then, when switching from the path switching control unit to the second communication speed is instructed during communication at the first communication speed, the path switching unit changes the communication path from the first communication speed to the second communication speed. The MPCP unit has a function of switching, and the MPCP unit has a function of transmitting a first switching instruction OAM frame to the ONU device.

  One ONU device is communicating at one of the first and second communication speeds with the path switching unit 23b that switches the data transmission path between the first and second communication speeds. And an operation control unit 27 for stopping the power supply to the circuit operating at one of the remaining communication speeds. When an OAM frame from the OLT device is received during communication at the first communication speed, the MPCP unit 23a detects this, and when the MPCP unit detects the first switching instruction OAM frame from the OLT device. The control signal for switching the communication path from the first communication speed to the second communication speed for the path switching unit and the power supply to the circuit operating at the first communication speed for the operation control unit are stopped. A path switching control unit 26a that emits a control signal.

  Further, the first MPCP unit 13a of the OLT device 10 has a function of detecting whether there is an ONU device that can be assigned to the first communication speed among the ONU devices that are communicating at the second communication speed. And the first path switching control unit 16a of the OLT device instructs the MPCP unit to switch the communication speed when the MPCP unit detects that there is an ONU device that can be assigned to the first communication speed. And the first path switching unit 13b of the OLT device has a function of switching the communication path from the second communication speed to the first communication speed when instructed to switch to the second communication speed. The first MPCP unit of the OLT device has a function of transmitting a second switching instruction OAM frame to the ONU device. On the other hand, when the second MPCP unit 23a of the ONU device 20 detects the second switching instruction OAM frame from the OLT device, the first switching speed is determined from the second communication speed to the path switching unit 23b. It has a function of issuing a control signal for switching the communication path to the communication speed and a control signal for stopping the power supply to the circuit operating at the second communication speed to the operation control unit 27.

  Here, the OLT device 10 and the ONU device 20 communicate at the first and second communication speeds in both the downstream communication from the OLT device to the ONU device and the upstream communication from the ONU device to the OLT device. The switching between the first and second communication speeds is performed simultaneously in the downlink communication and the uplink communication.

With the above configuration, the PON system 1 can switch the communication method from G-EPON to 10G-EPON only when necessary. As a result, power consumption is reduced, and efficient high-speed communication is possible.
Hereinafter, this will be described in more detail.

  FIG. 1 is an explanatory diagram showing a configuration of a PON system 1 according to the present invention. The PON system 1 is configured by connecting an OLT device 10 that is a device on the operator side and one or a plurality of ONU devices 20 that are devices on the subscriber side via P2MP via an optical cable 30. The OLT device 10 is connected to a host device on the operator side, and the ONU device 20 is connected to a terminal device on the subscriber side. In the PON system 1, communication from the OLT device 10 toward the ONU device 20 is called down, and conversely, communication from the ONU device 20 to the OLT device 10 is called up.

  In FIG. 1, the middle of the optical cable 30 is branched by a coupler 31, and thus three ONU devices 20a, 20b, and 20c are connected. However, this number is within the range that the OLT device 10 can accept (usually 32 units). (Or 64) or any number. The configurations of the ONU apparatuses 20a, 20b, and 20c are all the same, and are collectively referred to as the ONU apparatus 20.

  The OLT device 10 and the ONU device 20 can be connected using a communication standard of 10G-EPON which is uplink and downlink 10 Gbps communication and G-EPON which is uplink and downlink 1 Gbps communication. Here, the same optical cable 30 is used for 10G-EPON and G-EPON, and 10G-EPON in the downstream direction, G-EPON in the downstream direction, and 10G-EPON and G-in the upstream direction are included in this optical cable 30. EPON (time division), a communication line corresponding to each of the above is logically constructed. However, as will be described later, logical communication lines may be constructed on different optical cables for 10G-EPON and G-EPON.

  In addition, the OLT device 10 and the ONU device 20 simultaneously switch the communication method between 10G-EPON and G-EPON on the upstream side and the downstream side. That is, for example, when switching from G-EPON to 10G-EPON on the downstream side, switching from G-EPON to 10G-EPON is also performed on the upstream side. The same applies when switching from 10G-EPON to G-EPON.

  The OLT device 10 transmits and receives optical signals via the optical cable 30 to multiplex between 1 Gbps and 10 Gbps optical signals and convert optical signals and electrical signals. A SERDES (SERDES, Serialzer / Deserialzer) unit 12 that transmits and receives signals and converts serial signals and parallel signals to each other, and a PON termination unit 13 that transmits and receives parallel signals to and terminates the PON line with the cerdes unit 12 Prepare.

  The PON termination unit 13 includes an MPCP (Multi Point Control Protocol) unit 13a that transmits and receives parallel signals to and from the cerdes unit 12 and terminates the PON line, and a path switching unit 13b that distributes and aggregates frames transmitted and received with the MPCP unit 13a. Is provided.

  The OLT device 10 further transmits and receives a frame to and from the path switching unit 13b and temporarily stores the frame, and the frame buffer unit 14 transmits and receives frames to and from the frame buffer unit 14 to transmit and receive frames. SNI (Service Node Interface) terminating unit 15, and a processor 16 on which a path switching control unit 16 a that is a computer program for controlling the path switching unit 13 b and the MPCP unit 13 a operates.

  The route switching control unit 16a controls the MPCP unit 13a to perform G-EPON bandwidth monitoring and ONU device link speed change, and further controls the route switching unit 13b to monitor the frame amount and frame of each ONU device. It has a function to change the distribution destination.

  One ONU device 20 includes an optical transmission / reception unit 21 that transmits / receives an optical signal via the optical cable 30, a saddes unit 22 that transmits / receives an electrical signal to / from the optical transmission / reception unit 21 and converts a serial signal and a parallel signal, A PON termination unit 23 that transmits and receives parallel signals to and from the cerdes unit 22 and terminates the PON line is provided.

  The optical transmission / reception unit 21 is an optical division unit 21a that performs wavelength division and aggregation of 1 Gbps and 10 Gbps optical signals, and a 1G optical / electrical conversion unit that transmits and receives 1 Gbps optical signals to and from the optical division unit 21a and converts optical signals and electrical signals. 21b, and a 10G optical / electrical conversion unit 21c that transmits and receives a 10 Gbps optical signal and converts an optical signal and an electrical signal.

  The Sardes unit 22 transmits / receives electrical signals to / from the 1G optical / electrical converter 21b to convert serial signals and parallel signals, and 1G optical / electrical converter 21b transmits / receives electrical signals to / from the serial signals. And a 10G cerdes 22b for converting parallel signals.

  The PON termination unit 23 includes an MPCP unit 23a that transmits and receives parallel signals to and from the 1G cerdes 22a and 22b and terminates the PON line, and a path switching unit 23b that distributes and aggregates frames transmitted to and received from the MPCP unit 23a. Is provided.

  The ONU device 20 further transmits / receives a frame to / from the path switching unit 23b and temporarily stores the frame, and transmits / receives a frame to / from the frame buffer unit 24 to establish a network line with a higher-level device. Terminating UNI (User Network Interface) termination unit 25, processor 26 in which path switching control unit 26a which is a computer program for controlling operations of optical transmission / reception unit 21, cerdes 22 and PON termination unit 23 operates, and path switching control And an operation control unit 27 for controlling the operation of the optical transmission / reception unit 21 and the sardice unit 22 and the supply of electric power thereto by a control signal from the unit 26a.

  The path switching control unit 26a controls the path switching unit 23b to change the frame distribution destination, and controls the MPCP unit 23a to change the link speed of the ONU device and the path information necessary for communication to the operation control unit 27. And a notification function.

In the ONU device 20, when G-EPON is used for communication from the light splitting unit 21a to the path switching unit 23b, the route of the 1G optical / electrical conversion unit 21b to 1G cerdes 22a to MPCP unit 23a Use. On the other hand, when communication is performed using 10G-EPON, the route of the 1G optical / electrical converter 21b to 10G cerdes 22b and the MPCP 23a is used.
The functions and operations of the above units will be described in detail from the next stage.

(Operation of each part of OLT device)
First, the operation of each part of the OLT device 10 will be described. The optical transmission / reception unit 11 converts the 1 Gbps optical signal and the 10 Gbps optical signal received from the ONU device 20 via the optical cable 30 and the coupler 31 into a 1 Gbps electrical serial signal and a 10 Gbps electrical serial signal, respectively, and transmits the converted signal to the sades unit 12. On the other hand, the 1 Gbps electrical serial signal and the 10 Gbps electrical serial signal received from the sades unit 12 are converted into 1 Gbps optical signals and 10 Gbps optical signals of different wavelengths, multiplexed, and sent to the ONU device 20 via the optical cable 30 and the coupler 31. Send.

  The sardice unit 12 converts the 1 Gbps serial signal and the 10 Gbps serial signal received from the optical transmission / reception unit 11 into a 1 Gbps parallel signal and a 10 Gbps parallel signal, respectively, and transmits them to the MPCP unit 13a. On the other hand, the 1 Gbps parallel signal and the 10 Gbps parallel signal received from the MPCP unit 13 a are converted into a 1 Gbps serial signal and a 10 Gbps serial signal, respectively, and transmitted to the optical transceiver 11.

  The MPCP unit 13a establishes and maintains a logical link (Logical Link) in 10G-EPON or G-EPON with the ONU device 20, and executes MPCP for controlling PON section uplink communication. The MPCP unit 13a also detects a free band in the currently established logical link for communication. Further, the frame received from the cerdes 12 is transmitted to the path switching unit 13b, and the frames received from the lane switching unit 13b are transmitted to the cerdes 12. Further, an OAM (Operations, Administration, Maintenance) frame instructing switching of the link speed received from the path switching control unit 16a is transmitted to the target ONU device.

  The path switching unit 13b aggregates 10G-EPON and G-EPON frames received from the MPCP unit 13a and transmits them to the frame buffer unit 14. On the other hand, the frame received from the frame buffer unit 14 is distributed between 10G-EPON and G-EPON and transmitted to the MPCP unit 13a. Further, based on the notification from the path switching control unit 16a, the transmission destination of the frame for the specific ONU device is switched between 10G-EPON and G-EPON.

  The frame buffer unit 14 temporarily accumulates the frames received from the path switching unit 13 b and transmits the frames to the SNI termination unit 15. On the other hand, the frame received from the SNI termination unit 15 is temporarily accumulated and transmitted to the path switching unit 13b.

  The SNI termination unit 15 converts the frame received from the frame buffer unit 14 into a signal suitable for the network with the host device and transmits the signal. On the other hand, the signal received from the host device is converted into a signal (frame) suitable for data transfer inside the apparatus and transmitted to the frame buffer unit 14.

  The path switching control unit 16a monitors a communication band by G-EPON through the MPCP unit 13a. When it is detected that the uplink or downlink bandwidth in the G-EPON is saturated, the path switching control unit 16a monitors the uplink and downlink frame quantities flowing through the path switching unit 13b and communicates in the G-EPON. A switching instruction OAM frame is transmitted via the MPCP unit 13a so that the ONU device having the highest bandwidth occupancy among the ONU devices that are currently performing switching to communication using 10G-EPON. When the MPCP unit 13a is monitored to detect that the corresponding ONU device has established a 10G-EPON logical link, the path switching control unit 16a sends the downstream frame for the corresponding ONU apparatus to the path switching unit 13b. Control instruction to switch the transmission destination to 10G-EPON.

  On the other hand, the upstream and downstream frame amounts of any ONU device that monitors the path switching unit 13b and communicates with 10G-EPON can monitor the MPCP unit 13a and communicate using the free band of G-EPON. Is detected, the path switching control unit 16a transmits a switching instruction OAM frame via the MPCP unit 13a so as to switch the communication to the corresponding ONU device using G-EPON. When the MPCP unit 13a is monitored and the corresponding ONU device detects that a logical link in G-EPON has been established, the route switching control unit 16a controls the route switching unit 13b to control the corresponding ONU device. A control instruction for switching the transmission destination of the downstream frame to G-EPON is performed.

(Operation of each part of ONU device)
Next, the operation of each part of the ONU device 20 will be described. The optical dividing unit 21a performs wavelength division of the 1 Gbps optical signal and the 10 Gbps optical signal having different wavelengths received from the OLT device 10 via the optical cable 30 and the coupler 31, and performs the 1 Gbps optical signal to the 1G optical / electric converting unit 21b. Each optical signal is transmitted to the 1G optical / electrical converter 21b. On the other hand, the 1 Gbps optical signal received from the 1 G optical / electrical converter 21 b and the 10 Gbps optical signal received from the 1 G optical / electrical converter 21 b are transmitted to the ONU device 20 via the optical cable 30 and the coupler 31.

  The 1G optical / electrical converter 21b converts the 1 Gbps optical signal received from the optical splitter 21a into a 1 Gbps electrical serial signal, and transmits the 1 Gbps optical signal to the 1G cerdes 22a. On the other hand, the 1 Gbps electrical serial signal received from the 1G cerdes 22a is converted into a 1 Gbps optical signal and transmitted to the optical splitter 21a. Further, the operation starts and stops according to the notification from the operation control unit 27.

  The 10G optical / electrical converter 21c converts the 10 Gbps optical signal received from the optical splitter 21a into a 10 Gbps electrical serial signal, and transmits the 10 Gbps optical signal to the 10G cerdes 22b. On the other hand, the 10 Gbps electrical serial signal received from the 10G cerdes 22b is converted into a 10 Gbps optical signal and transmitted to the optical splitter 21a. Further, the operation starts and stops according to the notification from the operation control unit 27.

  The 1G Serdes unit 22a converts the 1 Gbps serial signal received from the 1G optical / electrical converter 21b into a 1 Gbps parallel signal and transmits the converted signal to the MPCP unit 23a. On the other hand, the 1 Gbps parallel signal received from the MPCP unit 23a is converted into a 1 Gbps serial signal and transmitted to the 1G optical / electrical converter 21b. Further, the operation starts and stops according to the notification from the operation control unit 27.

  The 10G cerdes 22b converts the 10 Gbps serial signal received from the 10G optical / electrical converter 21c into a 10 Gbps parallel signal and transmits the 10 Gbps parallel signal to the MPCP unit 23a. On the other hand, the 10 Gbps parallel signal received from the MPCP unit 23a is converted into a 10 Gbps serial signal and transmitted to the 10G optical / electrical conversion unit 21c. Further, the operation starts and stops according to the notification from the operation control unit 27.

  The MPCP unit 23a executes MPCP in order to establish and maintain a logical link in 10G-EPON or G-EPON with the OLT device 10 and to control PON section uplink communication. The MPCP unit 23a also transmits user traffic to the path switching unit 23b among the frames received from the 1G and 10G cerdes 22b, and an OAM frame notifying the switching of the link speed to the path switching control unit 26a.

  On the other hand, the frame received from the path switching unit 23b is transmitted to the 1G cerdes 22a when communicating by G-EPON and to the 10G cerdes 22b when communicating by 10G-EPON. Furthermore, 10G-EPON or G-EPON logical link establishment and logical link release are performed in accordance with a control signal from the path switching control unit 26a.

  The path switching unit 23 b aggregates and transmits the 10G-EPON frame and the G-EPON frame received from the MPCP unit 23 a to the frame buffer unit 24. On the other hand, the frame received from the frame buffer unit 24 is distributed between 10G-EPON and G-EPON and transmitted to the MPCP unit 23a. Further, the transmission destination of the frame for the OLT device 10 is switched between 10G-EPON and G-EPON in accordance with a control signal from the path switching control unit 26a.

  The frame buffer unit 24 temporarily accumulates the frames received from the path switching unit 23 b and transmits them to the UNI termination unit 25. On the other hand, the frame received from the UNI termination unit 25 is temporarily accumulated and transmitted to the path switching unit 23b.

  The UNI termination unit 25 replaces the frame received from the frame buffer unit with a signal (for example, 1000BASE-T) suitable for a network with a terminal device (such as a personal computer) and transmits the frame. On the other hand, the signal received from the terminal device is replaced with a signal (frame) suitable for data transfer inside the apparatus and transmitted to the frame buffer unit 24.

  When the path switching control unit 26a receives an OAM frame instructing switching to communication using 10G-EPON, the path switching control unit 26a instructs the operation control unit 27 to start the operation of the 10G-EPON circuit and detects that the operation has started. Then, the MPCP unit 23a is controlled to establish a 10G-EPON logical link. When the MPCP unit 23a is monitored and it is detected that a logical link in 10G-EPON is established, the path switching unit 23b is controlled to switch the transmission destination of the upstream frame for the OLT device 10 to 10G-EPON, When it is detected that the switching is completed, the operation control unit 27 is controlled to stop the operation of the G-EPON circuit and the supply of power to this circuit.

  On the other hand, the path switching control unit 26a that has received the OAM frame instructing switching to communication using G-EPON instructs the operation control unit 27 to start the operation of the G-EPON circuit and confirms that the operation has started. When detected, the MPCP unit 23a is controlled to establish a G-EPON logical link. When the MPCP unit 23a is monitored and it is detected that a logical link is established in G-EPON, the path switching unit 23b is controlled to switch the upstream frame transmission destination for the OLT device 10 to G-EPON, When it is detected that the switching has been completed, the operation control unit 27 is controlled to stop the operation of the 10G-EPON circuit.

  When the G-EPON communication is performed according to the control signal from the path switching control unit 26a, the operation control unit 27 supplies power to the 1G cerdes 22a and the 1G optical / electrical conversion unit 21b used in the G-EPON. The operation is started, and the operation of the 10G cerdes 22b and 10G optical / electrical converter 21c used in the 10G-EPON and the supply of power to these circuits are stopped. On the other hand, when communicating with 10G-EPON, 1G cerdes used for G-EPON are started by supplying power to 10G cerdes 22b and 10G optical / electric converter 21c used for 10G-EPON. The operation of the 22a and 1G optical / electrical converter 21b and the supply of power to these circuits are stopped.

(Communication speed switching flowchart)
FIG. 2 is a flowchart showing the operation of switching the communication speed on the OLT device 10 side in the PON system 1 shown in FIG. FIG. 3 is a flowchart showing the operation of switching the communication speed on the ONU device 20 side in the PON system 1 shown in FIG. In the initial state, it is assumed that the OLT device 10 and all the ONU devices 20 are communicating by G-EPON.

  First, on the OLT device 10 side, the path switching control unit 16a monitors the MPCP unit 13a to determine whether or not there is sufficient free bandwidth on the G-EPON downlink line (FIG. 2, step S101), and then. It is then determined whether there is sufficient free bandwidth on the G-EPON upstream line (step S102 in FIG. 2). If there is sufficient free bandwidth on both the downstream side and the upstream side of G-EPON, the determinations in steps S101 to S102 in FIG. 2 are repeated. Here, the determination of the free bandwidth on the downstream side and the upstream side may be made as to whether or not the free bandwidth has become “0”, or whether or not the free bandwidth has become a specific threshold value or less. May be determined.

  If there is not enough free bandwidth on either the downstream side or upstream side of G-EPON (Yes in step S101 or 102 in FIG. 2), the path switching control unit 16a monitors the path switching unit 13b, Compare the frame amount for each ONU device 20 communicating with G-EPON, determine the ONU device 20 with the highest bandwidth occupancy, and instruct to switch the communication path of the ONU device 20 to 10G-EPON The OAM frame to be transmitted is transmitted (FIG. 2, step S103).

  In the ONU device 20 that has received the OAM frame for switching to 10G-EPON (FIG. 3, step S201), the path switching control unit 26a causes the operation control unit 27 to start the operation of the 10G-EPON circuit. To send. Upon receiving this control signal, the operation control unit 27 starts supplying power to the 10G optical / electrical conversion unit 21c and the 10G cerdes 22b, and transmits an operation start control signal (step S202 in FIG. 3). At the same time, the operation control unit 27 notifies the path switching control unit 26a that the operation of the 10G-EPON circuit has started.

  Receiving this notification, the path switching control unit 26a transmits a control signal for establishing a logical link to the MPCP unit 23a. Upon receiving this control signal, the MPCP unit 23a transmits a register request to the 10G-EPON discovery gate to establish a logical link (FIG. 2, step S104, and FIG. Step S203).

  When the 10G-EPON logical link is established, in the OLT device 10, the route switching control unit 16a controls the route switching unit 13b to transmit the frame transfer destination for the ONU device 20 to the 10G-EPON (FIG. 2). Step S105).

  At the same time, the ONU device 20 also controls the path switching unit 23b to transmit the frame transfer destination for the OLT device 10 to the 10G-EPON (FIG. 3, step S204). At the same time, the path switching control unit 26a transmits a control signal for stopping the operation of the G-EPON circuit to the operation control unit 27 after confirming that communication with 10G-EPON has started. Receiving this, the operation control unit 27 stops the operation of the 1G optical / electrical conversion unit 21b and the 1G cerdes 22a, and stops the power supply (step S205 in FIG. 3).

  During communication with 10G-EPON, the path switching control unit 16a of the OLT device 10 monitors the MPCP unit 13a and communicates with each ONU device 20 communicating with 10G-EPON and G-EPON. Whether or not “the downlink communication amount of the ONU device 20 having the smallest downlink communication amount among the ONU devices 20 communicating by 10G-EPON” ≦ “the free capacity of the downlink communication path of the G-EPON”. That is, it is determined whether or not “there is any of the ONU devices 20 that are communicating by 10G-EPON that can be assigned the G-EPON with the downlink communication amount” (step S106 in FIG. 2).

  If step S106 is YES, the path switching control unit 16a then follows “on the upstream communication of the ONU device 20” for the ONU device 20 determined in step S106 that “downstream traffic can be allocated to G-EPON”. Amount ”≦“ Available capacity of G-EPON uplink communication path ”, that is,“ Whether or not the uplink communication amount of the ONU device 20 can be allocated to G-EPON ”is determined (step in FIG. 2). S107). If both steps S106 to S107 in FIG. 2 do not become yes, these determinations are repeated.

  If both steps S106 to S107 in FIG. 2 are yes, this means that some ONU devices 20 currently communicating with 10G-EPON can be switched to G-EPON communication. Means that. In that case, the operation of switching the communication path of the corresponding ONU device 20 from 10G-EPON to G-EPON is performed. In that case, the route switching control unit 16a of the OLT device 10 transmits an OAM frame that instructs the corresponding ONU device 20 to switch the communication route to G-EPON (FIG. 2, step S108).

  In the ONU device 20 that has received the OAM frame instructing switching to G-EPON (FIG. 3, step S206), the path switching control unit 26a causes the operation control unit 27 to start the operation of the G-EPON circuit. To send. Upon receiving this control signal, the operation control unit 27 starts supplying power to the 1G optical / electrical conversion unit 21b and the 1G cerdes 22a, and transmits an operation start control signal (step S207 in FIG. 3). At the same time, the operation control unit 27 notifies the path switching control unit 26a that the operation of the G-EPON circuit has started.

  Receiving this notification, the path switching control unit 26a transmits a control signal for establishing a logical link to the MPCP unit 23a. Receiving this control signal, the MPCP unit 23a transmits a register request to the G-EPON discovery gate (Discovory Gate) to establish a logical link (FIG. 2, step S109, and FIG. 3). Step S208).

  When the G-EPON logical link is established, in the OLT device 10, the route switching control unit 16a controls the route switching unit 13b to transmit the frame transfer destination for the ONU device 20 to the G-EPON (FIG. 2). Step S110).

  At the same time, the ONU device 20 also controls the path switching unit 23b to transmit the transfer destination of the frame for the OLT device 10 to the G-EPON (FIG. 3, step S209). At the same time, the path switching control unit 26a transmits a control signal for stopping the operation of the G-EPON circuit to the operation control unit 27 after confirming that communication with 10G-EPON has started. Receiving this, the operation control unit 27 stops the operation of the 10G optical / electrical conversion unit 21c and the 10G cerdes 22b, and stops the power supply (step S210 in FIG. 3).

  When step S110 in FIG. 2 is finished in the OLT device 10 and the operation in 10G-EPON is finished and the operation is started in G-EPON, the operation returns to step S101. Also in the ONU device 20, when step S210 in FIG. 3 is finished and the operation in 10G-EPON is finished and the operation is started in G-EPON, the operation returns to step S201.

(Communication mode switching)
FIG. 4 is a graph showing how the communication method is switched from G-EPON to 10G-EPON or from 10G-EPON to G-EPON shown in FIGS. FIGS. 4A and 4B show the states of the downlink and uplink, respectively, when switching from G-EPON to 10G-EPON. FIGS. 4C and 4D show the states of the downlink and uplink, respectively, when switching from 10G-EPON to G-EPON. Each of the OLT devices 10 is connected to five ONU devices 20, ONU devices 20 a to 20 e.

  In FIG. 4, the horizontal axis of the graph indicates 1 Gbps (in the case of G-EPON) or 10 Gbps (in the case of 10 G-EPON), and the ratio of the communication capacity of each ONU device 20 to 1 Gbps or 10 Gbps is indicated by the horizontal width of each block. It is.

  In the downlink, G-EPON and 10G-EPON transmit data using different wavelengths, and in FIGS. 4A and 4C, G-EPON and 10G-EPON are on separate horizontal axes. On the other hand, since G-EPON and 10G-EPON transmit data by time-sharing the same wavelength in the uplink, the G-EPON and 10G-EPON are the same in FIGS. 4B and 4D. The horizontal axis.

  FIG. 4A shows a state in which three ONU devices 20a, 20b, and 20c communicate with G-EPON, and two ONU devices 20d and 20e communicate with 10G-EPON. . Here, the total downlink communication capacity of each of the ONU devices 20a to 20c communicating with the G-EPON is close to 1 Gbps, and there is no more free capacity on the line on the G-EPON side.

  In this case, step S101 in FIG. 2 is YES, and the “ONU device 20a” having the highest bandwidth occupancy among the ONU devices 20 communicating by G-EPON is the target to be switched to 10G-EPON. At the same time when the downstream line is switched, the upstream line shown in FIG. 4B is also switched. The same switching operation is also performed when the total uplink communication capacity of each ONU device 20 communicating with G-EPON on the uplink line exceeds 1 Gbps.

  In FIG. 4C and FIG. 4D, the communication capacity of each ONU device 20 communicating with G-EPON is reduced on both downstream and upstream lines, and communication is performed with 10G-EPON. This shows a state where a margin sufficient to allocate the “ONU device 20a” having the lowest bandwidth occupancy among the ONU devices 20 to the G-EPON side is generated in the G-EPON side communication capacity.

  In this case, both of steps S106 to S107 in FIG. 2 are “yes”, and the “ONU device 20a” having the lowest bandwidth occupancy among the ONU devices 20 communicating by 10G-EPON is switched to G-EPON. It becomes a target. As shown in FIG. 4 (c) and FIG. 4 (d), the downlink and uplink are switched simultaneously.

(Overall operation of the first embodiment)
Next, the overall operation of the above embodiment will be described. The communication speed switching method according to the present embodiment is branched by an OLT (Optical Line Terminal) device, which is a carrier side communication device connected to one end of an optical fiber line, and an optical passive component inserted in the middle of the optical fiber line. The ONT (Optical Network Unit) device which is a plurality of subscriber side communication devices connected to the other end of the optical fiber line, and the OLT device and the corresponding ONU device have the first communication speed or the first communication speed. In a PON (Passive Optical Network) system 1 configured to be able to communicate with each other at a second communication speed higher than the first communication speed, the first communication between the OLT device and each ONU device The MPCP (Multi Point Control Protocol) unit of the OLT device detects the free bandwidth of the speed communication path, and the route switching control unit of the OLT device determines whether or not the free bandwidth detected by the MPCP unit is sufficient. And when the available bandwidth is not sufficient, the path switching control unit of the OLT device instructs the MPCP unit of the OLT device to switch to the second communication speed, and the second communication speed. In response to the switching instruction, the MPCP unit of the OLT device transmits the first switching instruction OAM frame to the ONU device having the highest bandwidth occupancy rate (step S104 in FIG. 2), and the path switching unit of the OLT device The communication path is switched from the first communication speed to the second communication speed (FIG. 2, step S105). During communication at the first communication speed, the MPCP unit of the ONU apparatus detects the OAM frame from the OLT apparatus, and the ONU When the MPCP unit of the device detects the first switching instruction OAM frame from the OLT device (step S201 in FIG. 3), the path switching control unit of the ONU device A control signal for switching the communication path from the first communication speed to the second communication speed, and a control signal for starting power supply to a circuit operating at the second communication speed, and according to the control signal The path switching unit of the ONU device switches the communication path to the second communication speed (FIG. 3, step S204), and the operation control unit of the ONU device stops supplying power to the circuit operating at the first communication speed. (FIG. 3, step S205).

Here, each of the above-described operation steps may be programmed so as to be executable by a computer, and these may be executed by the processors 16 and 26 which are computers that directly execute the respective steps. The program may be recorded on a non-temporary recording medium, such as a DVD, a CD, or a flash memory. In this case, the program is read from the recording medium by a computer and executed.
By this operation, this embodiment has the following effects.

  According to the present embodiment, the communication amount for each ONU device and the G-EPON bandwidth are compared, and the path between the OLT device and each ONU device can be switched between G-EPON and 10G-EPON. it can. Therefore, when the communication capacity is small, communication can be performed only with G-EPON with low power consumption, and the operation of the circuit related to 10G-EPON can be stopped to greatly reduce power consumption. Further, when the communication capacity increases and the free bandwidth is insufficient with G-EPON, the communication bandwidth can be expanded using 10G-EPON with a high communication speed.

  At that time, what is used for switching the communication method between the G-EPON and the 10G-EPON is a process with a small load, generally called “free bandwidth detection”. Therefore, this embodiment can be easily implemented on the basis of a known technique.

(Extension of the first embodiment)
FIG. 5 is an explanatory diagram illustrating a configuration of the PON system 301 according to the extension of the first embodiment. In the first embodiment described up to the previous stage, the same optical cable is used for 10G-EPON and G-EPON. However, in this extension, among the plurality of ONU devices 20, 10G-EPON and G -EPON uses the same optical cable and uses different optical cables.

  In the example shown in FIG. 5, the ONU device 20a uses the same optical cable 30a for 10G-EPON and G-EPON. Similarly, the ONU apparatuses 20b to 20d use the same optical cables 30b to 30d for 10G-EPON and G-EPON. In contrast, the ONU device 20e uses separate optical cables 30e and 30f for 10G-EPON and G-EPON, respectively. In FIG. 5, “upper and lower connections (G-EPON) by 1 Gbps” are indicated by broken arrows, and “up and down connections by 10 Gbps (10 G-EPON)” are indicated by thick solid arrows.

  There is no particular difference in the operation within the OLT device 10 and the ONU device 20 between the case where the same optical cable is used for 10G-EPON and G-EPON and the case where separate optical cables are used. That is, the internal configuration and operation of the OLT device 10 and the ONU device 20 are exactly the same as those described in the first embodiment. Accordingly, the same applies to the reference numbers.

  As long as the optical connection is normally branched and coupled by the coupler 31, even if the same optical cable and the one using different optical cables are mixed in 10G-EPON and G-EPON, the operation is possible. There is no particular problem. Furthermore, even if a plurality of ONU devices connected to the OLT device 10 can only communicate with one of 10G-EPON and G-EPON, The presence of the ONU device does not affect the operation according to the first embodiment and the extension described so far.

(Second Embodiment)
In the second embodiment of the present invention, the OLT device and the ONU device according to the first embodiment are communicated at the first and second communication speeds only for the downlink communication from the OLT device to the ONU device. It is possible, and the upstream communication from the ONU device to the OLT device is always performed at the first communication speed.

Even with this configuration simplified from that of the first embodiment, substantially the same effect as that of the first embodiment can be obtained.
Hereinafter, this will be described in more detail.

  FIG. 6 is an explanatory diagram showing the configuration of the PON system 401 according to the second embodiment of the present invention. The PON system 401 is configured by connecting an OLT device 410 and one or a plurality of ONU devices 420 via the optical cable 30 via P2MP. The optical cable 30 and the coupler 31 that branches along the way are the same as those in the first embodiment.

  The OLT device 410 and the ONU device 420 are either 10 / 1G-EPON with a downlink direction of 10 Gbps and an uplink direction of 1 Gbps (10G-EPON is standardized as 10 Gigabit Ethernet Passive Optical Network, IEEE802.3av) or G-EPON. It is possible to connect using. That is, the communication speed can be switched between 1 Gbps and 10 Gbps in the down direction, and the communication speed is fixed at 1 Gbps in the up direction. This is the difference between the first and second embodiments.

  As for the internal configurations of the OLT device 410 and the ONU device 420, first, the OLT device 410 is different from the OLT device 10 according to the first embodiment in that the optical transmission / reception unit 411, the saddes unit 12, and the PON termination unit 413 (MPCP unit) 413a and the path switching unit 413b) are only capable of 10 / 1G-EPON downlink communication for 10 Gbps communication, and both G-EPON uplink and downlink directions and 10 / 1G-EPON uplink direction for 1 Gbps communication. Communication is possible.

  Corresponding operations of the path switching control unit 416a are also slightly different from those in the first embodiment, and are therefore referred to by different reference numbers from those in the first embodiment. Except for this point, the configuration of the OLT device 410 is the same as that of the OLT device 10 according to the first embodiment, and the function of each element of the OLT device 410 is also the same as the element of the same name in the OLT device 10.

  Further, the internal configuration of the ONU device 420 is also different from that of the ONU device 20 according to the first embodiment in that the 10G optical / electrical conversion unit 421c, the 10G cerdes 422b, and the MPCP unit 423a are downstream of 10 / 1G-EPON. Only communication in the direction is possible, and 10 / 1G-EPON uplink communication uses the same route as G-EPON. Each unit related to G-EPON can perform both uplink and downlink communication as in the first embodiment.

  Therefore, the optical transmitter / receiver 421 including the 10G optical / electrical converter 421c, the cerdes 422 including the 10G cerdes 422b, and the PON terminator 423 including the MPCP 423a and the path switching unit 423b are the first implementations. The reference number is different from the form. Further, the operation of the path switching control unit 426a corresponding to this is partly different from that of the first embodiment. The operation control unit 427 also has a function of supplying power and starting and stopping the operation only for the 10G optical / electrical conversion unit 421c and the 10G cerdes unit 422b. Accordingly, each of these is referred to by a reference number different from that of the first embodiment.

  Except for this point, the configuration of the ONU apparatus 420 is the same as that of the ONU apparatus 20 according to the first embodiment, and the function of each element of the ONU apparatus 420 is also the same as the element of the same name in the ONU apparatus 20.

(Communication speed switching flowchart)
FIG. 7 is a flowchart showing the operation of switching the communication speed on the OLT device 410 side in the PON system 401 shown in FIG. FIG. 8 is a flowchart showing the operation of switching the communication speed on the ONU device 420 side in the PON system 401 shown in FIG. In the initial state, it is assumed that the OLT device 410 and all the ONU devices 420 are communicating by G-EPON.

  First, on the OLT device 410 side, the path switching control unit 416a monitors the MPCP unit 413a to determine whether or not there is a free bandwidth on the G-EPON downlink line (FIG. 7, step S601). If there is an available bandwidth on the downstream side of G-EPON, the determination in step S601 in FIG. 7 is repeated.

  When there is no free bandwidth on the downstream side of the G-EPON (Yes in step S601 in FIG. 7), the path switching control unit 416a monitors the path switching unit 413b for each ONU device 420 communicating with the G-EPON. Are compared to determine the ONU device 420 having the highest bandwidth occupancy rate and transmit an OAM frame instructing to switch the communication path of the ONU device 420 to 10 / 1G-EPON (FIG. 7, step). S602).

  In the ONU device 420 that has received the OAM frame instructing switching to 10 / 1G-EPON (FIG. 8, step S701), the path switching control unit 426a controls the operation control unit 427 to operate the 10 / 1G-EPON circuit. Send a control signal to start. Receiving this control signal, the operation control unit 427 starts supplying power to the 10G optical / electrical conversion unit 421c and the 10G cerdes 422b, and transmits an operation start control signal (step S702 in FIG. 8). At the same time, the operation control unit 427 notifies the path switching control unit 426a that the operation of the 10 / 1G-EPON circuit has started.

  Upon receiving this notification, the path switching control unit 426a transmits a control signal for establishing a logical link to the MPCP unit 423a. Receiving this control signal, the MPCP unit 423a transmits a register request to the 10 / 1G-EPON discovery gate to establish a logical link (FIG. 7, step S603, and FIG. 8. Step S703).

  When the 10 / 1G-EPON logical link is established, in the OLT device 410, the path switching control unit 416a controls the path switching unit 413b to transmit the frame transfer destination for the ONU device 420 to the 10 / 1G-EPON. (FIG. 7, step S604).

  At the same time, the ONU device 420 also controls the path switching unit 423b to transmit the frame transfer destination for the OLT device 410 to the 10 / 1G-EPON (FIG. 8, step S704). At the same time, the path switching control unit 426a transmits a control signal for stopping the operation of the G-EPON circuit to the operation control unit 427 after confirming that communication with 10G-EPON has started. Receiving this, the operation control unit 427 blocks the logical link in G-EPON.

  During communication with 10 / 1G-EPON, the path switching control unit 416a of the OLT device 410 monitors the MPCP unit 413a and communicates with each ONU device 420 communicating with 10 / 1G-EPON and G-EPON. Between the ONU devices 420 communicating with 10 / 1G-EPON, the amount of downlink communication of the ONU device 420 having the smallest downlink communication amount ≦ “the free capacity of the G-EPON downlink communication path In other words, whether or not there is an ONU device 420 communicating with 10 / 1G-EPON that can be assigned a downlink communication amount to G-EPON (FIG. 7). Step S605).

  If step S605 in FIG. 7 is YES, this means that there are some ONU devices 420 that are currently communicating with 10 / 1G-EPON in the downstream direction that can be switched to G-EPON communication. It means that. In that case, an operation of switching the communication path of the corresponding ONU device 420 from 10 / 1G-EPON to G-EPON is performed. In this case, the route switching control unit 416a of the OLT device 410 transmits an OAM frame that instructs the corresponding ONU device 420 to switch the communication route to G-EPON (FIG. 7, step S606).

  In the ONU device 420 that has received the OAM frame instructing switching to G-EPON (FIG. 8, step S706), the path switching control unit 426a transmits a control signal for establishing a logical link to the MPCP unit 423a. Upon receiving this control signal, the MPCP unit 423a transmits a register request to the G-EPON discovery gate (Discovory Gate) to establish a logical link (FIG. 7, step S607, and FIG. Step S707).

  When the G-EPON logical link is established, the OLT device 410 controls the route switching unit 413b so that the route switching control unit 416a transmits the frame transfer destination for the ONU device 420 to the G-EPON (FIG. 7). Step S608). Thereafter, the OLT device 410 repeats the processing from step S601.

  At the same time, the ONU device 420 also controls the path switching unit 23b to transmit the frame transfer destination for the OLT device 410 to the G-EPON (FIG. 8, step S708). At the same time, the path switching control unit 426a transmits a control signal for stopping the operation of the 10 / 1G-EPON circuit to the operation control unit 427 after confirming that the G-EPON communication is started. Receiving this, the operation control unit 427 stops the operation of the 10G optical / electrical conversion unit 421c and the 10G cerdes 422b, and stops the power supply (step S709 in FIG. 8).

  In the normal Internet, high-speed and large-capacity communication is mainly performed in the downlink direction, and the communication speed in the uplink direction is often smaller than that in the downlink direction. Therefore, the present embodiment has a more simplified configuration than the first embodiment, and can achieve substantially the same effect as the first embodiment.

(Extension of the second embodiment)
FIG. 9 is an explanatory diagram illustrating the configuration of the PON system 801 according to the expansion of the second embodiment. In the second embodiment described so far, the same optical cable is used for downlink 10G-EPON and G-EPON. However, in this extension, a plurality of ONU apparatuses 420 include 10G- EPON and G-EPON that use the same optical cable and those that use different optical cables are mixed. For the uplink, G-EPON communication is used between the OLT device 410 and all ONU devices 420.

  In the example shown in FIG. 9, the ONU device 420a uses the same optical cable 30a for 10 / 1G-EPON and G-EPON. Similarly, the ONU apparatuses 420b to 420d use the same optical cables 30b to 30d for 10 / 1G-EPON and G-EPON. In contrast, the ONU device 420e uses different optical cables 30e and 30f for 10 / 1G-EPON and G-EPON, respectively. In FIG. 9, “upper and lower 1 Gbps connection (G-EPON)” is indicated by a dashed arrow, and “upward 1 Gbps and downstream 10 Gbps (10 / 1G-EPON)” is indicated by a thick solid arrow.

  There is no particular difference in operation between the OLT device 410 and the ONU device 420 when the same optical cable is used for the downlink 10 / 1G-EPON and G-EPON and when different optical cables are used. That is, the OLT device 410 and the ONU device 420 have exactly the same internal configuration and operation as those described in the first embodiment. Accordingly, the same applies to the reference numbers.

  As in the case of the extension of the first embodiment, as long as the optical connection is normally branched and coupled by the coupler 31, the 10G-EPON and the G-EPON are different from those using the same optical cable. There is no particular problem in operation even if there is a mixture of those using optical cables.

  The present invention has been described with reference to the specific embodiments shown in the drawings. However, the present invention is not limited to the embodiments shown in the drawings, and any known hitherto provided that the effects of the present invention are achieved. Even if it is a structure, it is employable.

  About each embodiment mentioned above, it is as follows when the summary of the novel technical content is put together. In addition, although part or all of the said embodiment is summarized as follows as a novel technique, this invention is not necessarily limited to this.

(Supplementary Note 1) The optical fiber line branched by an OLT (Optical Line Terminal) device, which is a communication device on the business side connected to one end of the optical fiber line, and an optical passive component inserted in the middle of the optical fiber line The ONT (Optical Network Unit) device, which is a plurality of subscriber side communication devices connected to the other end of the network, the OLT device and the corresponding ONU device corresponding to the first communication speed or the first communication device. A PON (Passive Optical Network) system configured to be able to communicate with each other at a second communication speed higher than the communication speed,
The OLT device
A first path switching unit that switches between communication at the first and second communication speeds, and a free bandwidth of a communication path at the first communication speed between the OLT apparatus and each of the ONU apparatuses A first multi-point control protocol (MPCP) unit that detects an error, and whether or not the free band detected by the MPCP unit is sufficient to determine whether the free band is insufficient. A first path switching control unit for instructing switching to a communication speed of
The first path switching unit has a function of switching the communication path to the second communication speed when instructed to switch to the second communication speed during communication at the first communication speed. The PON system is characterized in that the first MPCP unit has a function of transmitting a first switching instruction OAM frame to the ONU device.

(Appendix 2) The ONU device is
A second path switching unit that switches between communication at one of the first and second communication speeds, and one communication speed that remains during communication at one of the first and second communication speeds And an operation control unit that stops power supply to the circuit operating in
A second MPCP unit that detects when an OAM frame is received from the OLT device during communication at the first communication speed;
When the MPCP unit detects the first switching instruction OAM frame from the OLT device, the MPCP unit causes the path switching unit to switch the communication path from the first communication speed to the second communication speed. A second path switching control unit that issues a control signal and a control signal that stops power supply to the circuit that operates at the first communication speed with respect to the operation control unit. Item 2. The PON system according to Item 1.

(Supplementary Note 3) Whether or not there is the ONU device that can be assigned to the first communication speed among the ONU devices that the first MPCP unit of the OLT device is communicating at the second communication speed. Has a function to detect
The first path switching control unit of the OLT device instructs the MPCP unit to switch the communication speed when the MPCP unit detects that the ONU device that can be allocated to the first communication speed exists. Has function,
The first path switching unit of the OLT device switches the communication path from the second communication speed to the first communication speed when instructed to switch to the second communication speed, and The MPCP unit of the OLT device has a function of transmitting a second switching instruction OAM frame to the ONU device,
When the second MPCP unit of the ONU device detects the second switching instruction OAM frame from the OLT device, the second route switching control unit controls the second route switching unit. A control signal for switching the communication path from the second communication speed to the first communication speed, and a control signal for stopping power supply to the circuit operating at the second communication speed with respect to the operation control unit; The PON system according to claim 2, which has a function of emitting

(Supplementary Note 4) The OLT device and the ONU device may perform the first and the second in both the downstream communication from the OLT device to the ONU device and the upstream communication from the ONU device to the OLT device. The communication can be performed at a communication speed of 2, and the switching between the first and second communication speeds is simultaneously performed in the downlink communication and the uplink communication. The PON system according to claim 1.

(Supplementary Note 5) The OLT device and the ONU device can communicate at the first and second communication speeds only for downlink communication from the OLT device to the ONU device, and from the ONU device to the OLT 4. The PON system according to claim 1, wherein the upstream communication toward the apparatus is performed at the first communication speed at all times. 5.

(Supplementary Note 6) Connected to an ONU (Optical Network Unit) device, which is a plurality of subscriber side communication devices connected to an optical fiber line branched by an optical passive component, and the first communication speed with each ONU device Alternatively, an OLT (Optical Line Terminal) which is a communication device on the operator side that constructs a PON (Passive Optical Network) system configured to be able to communicate with each other at a second communication speed higher than the first communication speed. A device,
A path switching unit that switches between communication at the first and second communication speeds;
An MPCP (Multi Point Control Protocol) unit for detecting a vacant bandwidth of a communication path of the first communication speed between the OLT device and each ONU device;
A path switching control unit that determines whether or not the free bandwidth detected by the MPCP unit is sufficient, and instructs the MPCP unit to switch to the second communication speed when the free bandwidth is insufficient With
When the switching to the second communication speed is instructed during communication at the first communication speed, the path switching unit has a function of switching the communication path to the second communication speed, and the MPCP The OLT device has a function of transmitting a first switching instruction OAM frame to the ONU device.

(Supplementary note 7) Connected to an OLT (Optical Line Terminal) device, which is an operator side communication device, via an optical fiber line branched by an optical passive component, and the OLT device and the first communication speed or the first communication An ONU (Optical Network Unit) device that is a subscriber-side communication device that constructs a PON (Passive Optical Network) system configured to be able to communicate with each other at a second communication speed higher than the speed,
A path switching unit that switches between communication at the first and second communication speeds;
An operation control unit that stops power supply to a circuit that operates at one communication speed remaining during communication at one of the first and second communication speeds;
An MPCP unit that detects when an OAM frame is received from the OLT device during communication at the first communication speed;
When the MPCP unit detects the first switching instruction OAM frame from the OLT device, the MPCP unit causes the path switching unit to switch the communication path from the first communication speed to the second communication speed. An ONU device comprising: a path switching control unit that issues a control signal and a control signal for stopping power supply to the circuit operating at the first communication speed to the operation control unit.

(Appendix 8) The optical fiber line branched by an OLT (Optical Line Terminal) device, which is a communication apparatus on the business side, connected to one end of the optical fiber line, and an optical passive component inserted in the middle of the optical fiber line The ONT (Optical Network Unit) device, which is a plurality of subscriber side communication devices connected to the other end of the network, the OLT device and the corresponding ONU device corresponding to the first communication speed or the first communication device. In a PON (Passive Optical Network) system configured to be able to communicate with each other at a second communication speed higher than the communication speed,
The first MPCP (Multi Point Control Protocol) unit of the OLT device indicates a free bandwidth of the communication route of the first communication speed between the OLT device and each ONU device during communication at the first communication speed. Detects
The first path switching control unit of the OLT device determines whether or not the free bandwidth detected by the MPCP unit is sufficient,
When the free bandwidth is not sufficient, the first path switching control unit of the OLT device instructs the first MPCP unit of the OLT device to switch to the second communication speed,
In response to the switching instruction to the second communication speed, the first MPCP unit of the OLT apparatus transmits a first switching instruction OAM frame to the ONU apparatus and the first OTP frame of the OLT apparatus. A path switching unit switches the communication path from the first communication speed to the second communication speed;
The second MPCP unit of the ONU device detects an OAM frame from the OLT device during communication at the first communication speed,
When the second MPCP unit of the ONU device detects the first switching instruction OAM frame from the OLT device, the second path switching control unit of the ONU device determines from the first communication speed. A control signal for switching the communication path to the second communication speed and a control signal for starting power supply to a circuit operating at the second communication speed;
In response to the control signal, the second path switching unit of the ONU device switches the communication path to the second communication speed, and the operation control unit of the ONU apparatus operates at the first communication speed. A communication speed switching method characterized by stopping the power supply to the network.

(Supplementary note 9) An OLT (Optical Line Terminal) device, which is a provider side device connected to one end of an optical fiber line, and the optical fiber line branched by an optical passive component inserted in the middle of the optical fiber line It comprises an ONU (Optical Network Unit) device which is a plurality of subscriber-side devices connected to the other end, and the OLT device and each ONU device are faster than the first communication speed or the first communication speed. PON (Passive Optical Network) system that can communicate with each other at a second communication speed,
In the computer provided in the OLT device,
A procedure for detecting a free bandwidth of a communication path of the first communication speed between the OLT device and each of the ONU devices during communication at the first communication speed;
A procedure for determining whether or not the free bandwidth detected by the MPCP unit is sufficient;
A procedure for instructing the MPCP unit of the OLT device to switch to the second communication speed when the free bandwidth is not sufficient;
In response to the switching instruction to the second communication speed, the MPCP unit of the OLT apparatus transmits a first switching instruction OAM frame to the ONU apparatus and the path switching control unit of the OLT apparatus A procedure for switching the communication path from the first communication speed to the second communication speed;
A communication speed switching program characterized in that

(Supplementary Note 10) An OLT (Optical Line Terminal) device, which is a provider side device connected to one end of an optical fiber line, and the optical fiber line branched by an optical passive component inserted in the middle of the optical fiber line It comprises an ONU (Optical Network Unit) device which is a plurality of subscriber-side devices connected to the other end, and the OLT device and each ONU device are faster than the first communication speed or the first communication speed. PON (Passive Optical Network) system that can communicate with each other at a second communication speed,
In the computer provided in the ONU device,
A procedure for causing the MPCP unit of the ONU device to detect an OAM frame from the OLT device during communication at the first communication speed;
A control signal for switching the communication path from the first communication speed to the second communication speed when the MPCP unit of the ONU apparatus detects the first switching instruction OAM frame from the OLT apparatus; Issuing a control signal for stopping power supply to a circuit operating at the first communication speed;
A communication speed switching program characterized in that

  The present invention can be used in a PON system. In particular, it is suitable for use in a PON system capable of switching a plurality of communication speeds.

1, 301, 401, 801 PON system 10, 410 OLT device 11, 21, 411, 421 Optical transceiver 12, 22, 412, 422 Sardes 13, 23, 413, 423 PON termination 13a, 23a, 413a, 423a MPCP unit 13b, 23b, 413b, 423b Path switching unit 14, 24 Frame buffer unit 15 SNI termination unit 16, 26 Processor 16a, 26a, 416a, 426a Path switching control unit 20, 20a-20e, 420, 420a-420e ONU device 21a Optical splitter 21b 1G optical / electrical converter 21c, 421c 10G optical / electrical converter 22a 1G cerdes 22b, 422b 10G cerdes 25 UNI termination 27, 427 Operation controller 30, 30a-30f Optical cable 31 Coupler

Claims (8)

At the other end of the optical fiber line branched by an OLT (Optical Line Terminal) device, which is a communication device on the operator side connected to one end of the optical fiber line, and an optical passive component inserted in the middle of the optical fiber line It comprises an ONU (Optical Network Unit) device that is a plurality of connected communication devices on the subscriber side, and the OLT device and the corresponding ONU device are faster than the first communication speed or the first communication speed. A PON (Passive Optical Network) system configured to be able to communicate with each other at a second communication speed,
The OLT device
A first path switching unit that switches between communication at the first and second communication speeds, and a free bandwidth of a communication path at the first communication speed between the OLT apparatus and each of the ONU apparatuses A first MPCP (Multi Point Control Protocol) unit that detects the bandwidth, and whether or not the free bandwidth detected by the MPCP unit is sufficient, and the bandwidth occupancy is highest when the free bandwidth is not sufficient A first path switching control unit that identifies the ONU device and instructs the MPCP unit to switch the communication with the identified ONU device to the second communication speed;
The first path switching unit has a function of switching the communication path to the second communication speed when instructed to switch to the second communication speed during communication at the first communication speed. , PON system characterized by having a function of said first MPCP unit transmits a first switching instruction OAM frame to the identified ONU apparatus. The ONU device is
A second path switching unit that switches between communication at one of the first and second communication speeds, and one communication speed that remains during communication at one of the first and second communication speeds And an operation control unit that stops power supply to the circuit operating in
A second MPCP unit that detects when an OAM frame is received from the OLT device during communication at the first communication speed;
When the MPCP unit detects the first switching instruction OAM frame from the OLT device, the MPCP unit causes the path switching unit to switch the communication path from the first communication speed to the second communication speed. A second path switching control unit that issues a control signal and a control signal that stops power supply to the circuit that operates at the first communication speed with respect to the operation control unit. Item 2. The PON system according to Item 1. The first MPCP unit of the OLT device detects whether or not the ONU device that can be assigned to the first communication speed exists among the ONU devices that are communicating at the second communication speed. Has function,
The first path switching control unit of the OLT device instructs the MPCP unit to switch the communication speed when the MPCP unit detects that the ONU device that can be allocated to the first communication speed exists. Has function,
The first path switching unit of the OLT device switches the communication path from the second communication speed to the first communication speed when instructed to switch to the second communication speed, and The MPCP unit of the OLT device has a function of transmitting a second switching instruction OAM frame to the ONU device,
When the second MPCP unit of the ONU device detects the second switching instruction OAM frame from the OLT device, the second route switching control unit controls the second route switching unit. A control signal for switching the communication path from the second communication speed to the first communication speed, and a control signal for stopping power supply to the circuit operating at the second communication speed with respect to the operation control unit; The PON system according to claim 2, which has a function of emitting   The OLT device and the ONU device have the first and second communication speeds in both the downstream communication from the OLT device to the ONU device and the upstream communication from the ONU device to the OLT device. 4. The communication apparatus according to claim 1, wherein the first communication speed and the second communication speed are switched simultaneously in the downlink communication and the uplink communication. 5. The PON system described.   The OLT device and the ONU device can communicate at the first and second communication speeds only for downlink communication from the OLT device to the ONU device, and from the ONU device to the OLT device. 4. The PON system according to claim 1, wherein the upstream communication is always performed at the first communication speed. 5. Connected to an ONU (Optical Network Unit) device, which is a plurality of subscriber side communication devices connected to an optical fiber line branched by an optical passive component, and each ONU device and the first communication speed or the first An OLT (Optical Line Terminal) device that is a communication device on the business side that constructs a PON (Passive Optical Network) system configured to be able to communicate with each other at a second communication speed higher than the communication speed of ,
A path switching unit that switches between communication at the first and second communication speeds;
An MPCP (Multi Point Control Protocol) unit for detecting a vacant bandwidth of a communication path of the first communication speed between the ONU devices ;
It is determined whether or not the free bandwidth detected by the MPCP unit is sufficient, and when the free bandwidth is not enough, the ONU device having the highest bandwidth occupancy rate is identified, and the identified ONU device A path switching control unit that instructs the MPCP unit to switch to the second communication speed of communication between
When the switching to the second communication speed is instructed during communication at the first communication speed, the path switching unit has a function of switching the communication path to the second communication speed, and the MPCP An OLT apparatus, wherein a unit has a function of transmitting a first switching instruction OAM frame to the identified ONU apparatus. At the other end of the optical fiber line branched by an OLT (Optical Line Terminal) device, which is a communication device on the operator side connected to one end of the optical fiber line, and an optical passive component inserted in the middle of the optical fiber line It comprises an ONU (Optical Network Unit) device that is a plurality of connected communication devices on the subscriber side, and the OLT device and the corresponding ONU device are faster than the first communication speed or the first communication speed. A PON (Passive Optical Network) system configured to be able to communicate with each other at a second communication speed,
The first MPCP (Multi Point Control Protocol) unit of the OLT device indicates a free bandwidth of the communication route of the first communication speed between the OLT device and each ONU device during communication at the first communication speed. Detects
The first path switching control unit of the OLT device determines whether or not the free bandwidth detected by the MPCP unit is sufficient,
When the free bandwidth is not sufficient, the first path switching control unit of the OLT device identifies the ONU device with the highest bandwidth occupancy rate and the second communication of communication with the identified ONU device . Instructing the first MPCP unit of the OLT device to switch to the communication speed of
According to the switching instruction to the second communication speed, the said OLT device together with the first MPCP portion of the OLT device transmits a first switching instruction OAM frame to the identified ONU device A first path switching unit switching the communication path from the first communication speed to the second communication speed;
The second MPCP unit of the ONU device detects an OAM frame from the OLT device during communication at the first communication speed,
When the second MPCP unit of the ONU device detects the first switching instruction OAM frame from the OLT device, the second path switching control unit of the ONU device determines from the first communication speed. A control signal for switching the communication path to the second communication speed and a control signal for starting power supply to a circuit operating at the second communication speed;
In response to the control signal, the second path switching unit of the ONU device switches the communication path to the second communication speed, and the operation control unit of the ONU apparatus operates at the first communication speed. A communication speed switching method characterized by stopping the power supply to the network. At the other end of the optical fiber line branched by an OLT (Optical Line Terminal) device, which is a communication device on the operator side connected to one end of the optical fiber line, and an optical passive component inserted in the middle of the optical fiber line It comprises an ONU (Optical Network Unit) device that is a plurality of connected communication devices on the subscriber side, and the OLT device and the corresponding ONU device are faster than the first communication speed or the first communication speed. A PON (Passive Optical Network) system configured to be able to communicate with each other at a second communication speed,
In the computer provided in the OLT device,
A procedure for detecting a free bandwidth of a communication path of the first communication speed between the OLT device and each of the ONU devices during communication at the first communication speed;
A procedure for determining whether or not the free bandwidth detected by the MPCP unit is sufficient;
When the free bandwidth is not sufficient, the ONU device having the highest bandwidth occupancy rate is specified, and the OLT device previously switches the communication with the specified ONU device to the second communication speed. procedure instructs the MPCP (Multi Point Control Protocol) unit comprising,
And according to the switching instruction to the second communication speed, the path switching control of the OLT device the causes transmit the first switching instruction OAM frame to the identified ONU apparatus to the MPCP of the OLT device A step of causing the unit to switch the communication path from the first communication speed to the second communication speed;
A communication speed switching program characterized in that

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