JP6015323B2 - Communication system, communication method, relay device, and master station device - Google Patents

Description

  The present invention relates to a communication system in which communication networks for performing uplink multiple access control, such as PON (Passive Optical Network), are hierarchically connected, a relay device and a master station device used in the communication system, and communication thereof The present invention relates to a communication method performed in the system.

The PON system is an optical communication system that performs optical branching in P2MP (Point to Multi Point) connection mode without power, and branches from OLT (Optical Line Terminal) and optical fiber connected to this to multiple optical fibers. And an ONU (Optical Network Unit) connected to each end of the branched optical fiber.
In this PON system, an NRZ (Non-Return to Zero) optical signal obtained by directly or externally modulating a light source such as a semiconductor laser is transmitted to transmit / receive information.

The downstream optical signal transmitted by the OLT is transmitted to each ONU in a broadcast format, and each ONU receives only the signal addressed to itself.
Conversely, upstream optical signals from the ONU are managed by the OLT in a time division multiplexing manner to prevent collisions, and the OLT receives upstream optical signals from each ONU in bursts (Patent Documents 1 and 2). reference).

JP 2004-289780 A JP 2007-243285 A

In the above conventional PON system, there is a physical upper limit to the optical output intensity of the transmitter for optical transmission and a physical lower limit to the reception sensitivity of the receiver. Therefore, the transmission distance and branch from the OLT to the ONU As the number increases, the intensity of the optical signal input to the receiver decreases.
For this reason, in the PON system, it is common to limit the transmission distance and the number of branches of the optical fiber line. For example, the transmission distance is limited to 20 km and the number of branches is limited to 32 branches or less.

Therefore, the PON is hierarchically connected by a relay device that functions as an ONU in the upper PON and functions as an OLT in the lower PON, and the relay device is independent of the upstream multiple access control of the upper PON by the OLT. It is conceivable that the optical communication system performs uplink multiple access control.
If such a multi-stage optical communication system is adopted, the transmission distance can be increased to a value obtained by adding the upper PON and the lower PON, and the number of branches is the upper PON and the lower PON. It can be increased to a value multiplied by minutes.

However, in a system that performs uplink multiple access control independently between the upper communication network and the lower communication network, such as the optical communication system described above, the OLT that is the parent station of the upper communication network uses the lower communication network of the upstream data frame. In some cases, the SLA (Service Level Agreement) of the ONU that is a child station of the lower communication network cannot be achieved.
In view of such conventional problems, the present invention provides a communication system that performs uplink multiple access control independently in the upper and lower communication networks, and is capable of reliably achieving the SLA of the slave station on the lower stage. 1 purpose.

In addition, when relay devices are installed at remote locations away from the OLT, maintenance management of ONUs that are slave stations of the lower communication network is required unless each relay device is connected to a management network managed by a communication carrier. There is also a problem that cannot be performed.
In view of such conventional problems, the present invention can perform maintenance management of a slave station on the lower stage from the master station on the upper stage in a communication system that performs independent multiple access control in the upper and lower communication networks. The second purpose is to do so.

  (1) A communication system according to the present invention includes a first communication network in which a master station device performs uplink multiple access control on a relay device, and a second communication network in which the relay device performs uplink multiple access control on a slave station device. A communication system in which the first communication network and the second communication network are connected via one or more relay devices, and the relay device connected to the second communication network is the second communication network. Tag information for identifying the slave station device that is the transmission source is added to the upstream data frame transferred from the communication network to the first communication network, and the master station device receives the received data from the first communication network. Based on the tag information included in the data frame, the amount of upstream traffic is aggregated for each slave station device.

According to the communication system of the present invention, the relay device gives the tag information to the uplink data frame, and the master station device determines the uplink traffic volume based on the tag information included in the data frame. Aggregate every. Therefore, the master station apparatus can provide QoS (Quality of Service) suitable for the SLA for each slave station apparatus based on the aggregated traffic volume.
For this reason, it is possible to reliably achieve the SLA of the slave station apparatus on the lower side, and the first object is achieved.

(2) In the communication system of the present invention, the aggregation for each slave station device may include aggregation for each priority defined for the data frame.
Information indicating the priority of the data frame is obtained by referring to a specific field in the data frame. For example, in the Tos (Type of Service) field in the header of the IPv4 frame, the TC (Traffic Class) field in the header of the IPv6 frame, or the PCP (Priority Code Point) field defined in IEEE Std 802.1Q ^TM -2011 Based on this, the priority of the data frame can be determined. The field value and priority mapping rules must be defined separately.

According to the communication system of the present invention, the relay device gives the tag information to the uplink data frame, and the master station device determines the uplink traffic volume based on the tag information included in the data frame. Aggregate for each priority. Therefore, the master station apparatus can provide QoS (Quality of Service) corresponding to the SLA for each priority for each slave station apparatus based on the aggregated traffic volume.
For this reason, even when the SLA of the slave station apparatus on the lower stage side includes the QoS condition for each type of traffic, the SLA can be reliably achieved, and the first object is achieved.

(3) In the communication system of the present invention, it is sufficient for the relay apparatus to add tag information for identifying the slave station apparatus to the data frame, and it is not necessary to add tag information for identifying the own apparatus. .
In this case, the master station device determines the data based on a combination of the tag information (tag information of the slave station device) included in the data frame and the logical link number of the relay device in the first communication network. The slave station device that is the transmission source of the frame can be specified.

(4) However, in the communication system of the present invention, the relay device may add tag information for identifying the own device to the data frame in addition to tag information for identifying the slave station device. Good.
In this case, the master station apparatus can identify the slave station apparatus that is a transmission source of the data frame based on a combination of the two types of tag information included in the data frame.

  (5) The relay device of the present invention is a relay device (sub-combination) that constitutes the communication system described in (1) above, and has the same effects as the communication system.

  That is, the relay apparatus according to the present invention is a relay apparatus capable of communicating in both the first communication network and the second communication network, and performs the second communication according to the uplink multiple access control performed by the master station apparatus of the first communication network. For performing uplink multiple access control on a slave station device of a communication network, and for identifying the slave station device that is the transmission source in an upstream data frame transferred from the second communication network to the first communication network Tag information is added.

  (6) The master station device of the present invention is a master station device (sub-combination) constituting the communication system described in (1) above, and has the same operational effects as the communication system.

  That is, the master station apparatus of the present invention is a relay apparatus that performs uplink multiple access control for a slave station apparatus of the second communication network, and a master station apparatus that communicates in the first communication network. And performing uplink multiple access control based on tag information for identifying the slave station device that is the transmission source included in the uplink data frame received from the relay device, It is characterized by tabulating for each device.

  (7) The communication method of the present invention is a communication method performed in the communication system according to (1) described above, and has the same effects as the communication system.

  That is, in the communication method of the present invention, the master station device of the first communication network performs uplink multiple access control on the relay device, and the relay device performs uplink multiple access control on the slave station device of the second communication network. A communication method for performing tag information for identifying the slave station device that is a transmission source of the uplink data frame transferred from the second communication network to the first communication network; and A step of counting the amount of upstream traffic for each of the slave station devices based on the tag information included in the data frame.

  (8) The communication system of the present invention from another viewpoint includes a first communication network in which a master station device performs uplink multiple access control on a relay device, and an uplink multiple access from the relay device to a slave station device. A second communication network that performs control is a communication system connected via the relay device, and the master station device manages the slave station function unit of the first communication network included in the relay device. A virtual frame for performing management of the master station function unit of the second communication network included in the relay device and capable of transmitting / receiving the management frame of the first format for performing to / from the relay device. A control system communication path can be set in the first communication network, and the relay apparatus can transmit and receive a management frame of a second format for managing the slave station apparatus to and from the slave station apparatus. Yes, the slave station device When a command for instructing maintenance management is received from the master station device via the control system communication path, a management frame of the second format is transmitted to and received from the slave station device, and the slave station device Based on the response, a response to the command is sent to the master station device via the control system communication path.

As the management frame, for example, an OAM (Operations, Administration, and Maintenance) frame defined by IEEE Std 802.3 ^TM -2008 is conceivable.
In the PON defined by IEEE Std 802.3 ^TM -2008, ONU maintenance and management is performed using an OAM frame or an extended OAM frame obtained by extending the format of the OAM frame (hereinafter collectively referred to as “OAM frame”). It can be carried out. The control system communication path can be set using, for example, a VLAN.

According to the communication system of the present invention, the master station device can set a virtual control system communication path for managing the master station function unit of the relay device in the first communication network. Based on the response from the slave station device obtained by transmission / reception of the management frame with the slave station device when a command instructing maintenance management for the device is received from the master station device via the control communication channel, A response to the command of the master station device is made via the control system communication path.
For this reason, maintenance management of the slave station apparatus on the lower stage can also be performed from the parent station apparatus on the upper stage, and the second object described above is achieved.

(9) In the communication system according to the present invention, the master station device may transmit a setting for a portion other than the slave station function unit of the relay device in a management frame of the first format.
In this case, if the relay device performs setting processing for a portion other than the slave station function unit of the device according to the contents of the management frame of the first format, the control system communication path is not used. The setting of the part other than the slave station function unit of the relay apparatus can also be performed by remote operation via the master station apparatus.

  (10) The relay device of the present invention is a relay device (sub-combination) constituting the communication system according to (7) described above, and has the same operational effects as the communication system.

  That is, the relay apparatus according to the present invention is a relay apparatus capable of communicating in both the first communication network and the second communication network, and performs the second communication according to the uplink multiple access control performed by the master station apparatus of the first communication network. Performs uplink multiple access control for a slave station device of a communication network, can transmit / receive a management frame for managing the slave station device to / from the slave station device, and instructs maintenance management for the slave station device A command to be received from the master station device via the control system communication path, based on a response from the slave station device obtained by transmitting and receiving a management frame to and from the slave station device, A response to the command of the station apparatus is performed via the control system communication path.

  (11) The communication method of the present invention is a communication method performed in the communication system according to (7) described above, and has the same effects as the communication system.

  That is, in the communication method of the present invention, the master station device of the first communication network performs uplink multiple access control on the relay device, and the relay device performs uplink multiple access control on the slave station device of the second communication network. In the communication method, the master station device and the relay device transmit and receive a management frame for management of a slave station function unit of the relay device, and the relay device and the slave station device communicate with the slave station device. Transmitting and receiving a management frame for managing the slave station, and when the relay device receives a command for instructing maintenance management for the slave station device from the master station device via the control system communication path, the slave station Performing a response to the command of the master station device via the control system communication path based on a response from the slave station device obtained by transmitting and receiving a management frame to and from the device. Be

(12) In the communication system of the present invention, the relay apparatus absorbs a difference between a transmission rate of an uplink signal transmitted to the first communication network and a transmission rate of an uplink signal received from the second communication network. It is preferable to have an upstream buffer.
In this case, a communication system in which the upstream transmission rate (for example, 10 Gbps) of the first communication network is higher than the upstream transmission rate (for example, 1 Gbps) of the second communication network can be configured, and the number of branches in the first communication network is increased. However, the upstream bandwidth per user can be effectively secured.

(13) In the communication system of the present invention, the relay device absorbs a difference between a transmission rate of a downlink signal received from the first communication network and a transmission rate of a downlink signal transmitted to the second communication network. It is preferable to have a downstream buffer.
In this case, a communication system in which the downlink transmission rate (for example, 10 Gbps) of the first communication network is higher than the downlink transmission rate (for example, 1 Gbps) of the second communication network can be configured, and the number of branches in the first communication network is increased. However, it is possible to effectively secure the downstream bandwidth per user.

As described above, according to the present invention, it is possible to reliably achieve the SLA of the slave station apparatus on the lower side in the communication system that performs the uplink multiple access control independent of the upper and lower communication networks.
Further, according to the present invention, in a communication system that performs uplink multiple access control independently in the upper and lower communication networks, maintenance management of the lower slave station can be easily performed from the upper master station. Can do.

It is a figure which shows the connection form of the optical communication system which concerns on embodiment of this invention. It is a block diagram which shows the structure of a main | base station apparatus. It is a block diagram which shows the structure of a relay apparatus. It is a block diagram which shows the structure of a subunit | mobile_unit apparatus. It is a figure which shows an example of the frame format of an upstream data frame. It is a block diagram which shows the modification of a relay apparatus. It is a figure which shows the virtual control system communication path between a master station apparatus and a relay apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Connection form of optical communication system]
FIG. 1 is a diagram showing a connection form of an optical communication system according to an embodiment of the present invention.
As shown in FIG. 1, in the optical communication system of this embodiment, a single master station device 10 and a large number of slave station devices 30 are interleaved with a plurality of relay devices 20 between them, and the upper and lower two-stage PON lines L1. , L2 are connected to each other (topology).

That is, one master station device 10 and a plurality of relay devices 20 under its control are connected in an optical fiber in the P2MP form, and each relay device 20 and a plurality of slave station devices 30 under its control are used as optical fibers. Connected in P2MP form.
More specifically, a single-core optical fiber connected to the master station device 10 is branched into a plurality of single-core optical fibers via an optical coupler C1 that is a passive optical branch node. A relay device 20 is connected to each end of the optical fiber.

The single-core optical fiber connected to the lower side of the relay device 20 is branched into a plurality of single-core optical fibers via an optical coupler C2 that is a passive optical branching node. Each of the slave station devices 30 is connected to the end of each.
Accordingly, there is only one upper PON line L1 corresponding to the master station apparatus 10 which is one OLT, and the lower PON line L2 corresponds to the relay apparatus 20 corresponding to a plurality of relay apparatuses 20. There are as many as.

Since the relay device 20 functions as an OLT in the lower PON line L2, the optical communication system of the present embodiment includes one “large-scale” from the master station device 10 and a plurality of relay devices 20 under its control. It can also be considered that “OLT” is virtually configured.
Further, as indicated by a broken line in FIG. 1, the slave station device 30 that is the ONU of the PON may be directly connected to the PON line 1 on the upper side, or the relay device 20 is further connected to the PON line L2 on the lower side. The relay device 20 may have a plurality of hierarchies.

In the present specification, the upper PON composed of the master station device 10, the PON line L1, and the plurality of relay devices 20 may be referred to as “upper PON” or “first communication network”. The lower PON composed of the PON line 2 and the plurality of slave station devices 30 may be referred to as “lower PON” or “second communication network”.
In the present embodiment, since the PON is assumed as the upper and lower communication networks, the master station device 10 is “OLT” and the slave station device 30 is “ONU”.

In the optical communication system of FIG. 1, the upstream optical signal having the wavelength λ1 and the transmission rate R1 [Gbps] is used in the upstream communication of the upper PON. However, the upstream transmission rate R1 of the upper stage PON may be a plurality of types instead of one.
In upstream communication in the lower PON, an upstream optical signal having a wavelength λ3 and a transmission rate R3 [Gbps] is used. However, the upstream transmission rate R3 of the lower stage PON may be a plurality of types instead of one.

In the downstream communication of the upper PON, a downstream optical signal having a wavelength λ2 and a transmission rate R2 is used, and the wavelength λ2 and the transmission rate R2 are fixed to one type. Of course, the downstream optical signal of the upper stage PON may be a plurality of types instead of one type, and in this case, signals having wavelengths different from λ2 are multiplexed.
In the downstream communication of the lower stage PON, a downstream optical signal having a wavelength λ4 and a transmission rate R4 is used, and the wavelength λ4 and the transmission rate R4 are fixed to one type. However, the downstream optical signal in the lower stage PON may be a plurality of types instead of one type, and in this case, signals having wavelengths different from λ4 are multiplexed.

In the present embodiment, for example, R1 = 10, R2 = 10, R3 = 1, and R4 = 1 are assumed as the transmission rates R1 to R4.
Therefore, the upper stage PON in which the master station device 10 and the relay device 20 are connected by the PON line L1 has a transmission rate R1, R2 of 10 Gbps (baud rate is 10.3125 Gbaud) and is 10G-EPON. In the lower stage PON connected by the PON line L2, the transmission rates R3 and R4 are G-EPON of 1 Gbps (baud rate is 1.25 Gbaud).

In this case, the wavelengths λ1 and λ2 of the upper PON can be selected from the ranges of 1260 nm ≦ λ1 ≦ 1280 nm and 1575 nm ≦ λ2 ≦ 1580 nm, for example, according to the Clause 75 convention of IEEE 802.3av-2009.
Further, the wavelength of the lower PON can be selected from the ranges of 1260 nm ≦ λ3 ≦ 1360 nm and 1480 nm ≦ λ4 ≦ 1500 nm, for example, according to the rules of Clause 60 of IEEE 802.3-2008.

As shown in FIG. 1, the master station device 10 is connected to a “higher network” that is a public network, and each slave station device 30 is connected to a “user network” that is a private communication network.
Accordingly, a terminal device (not shown) such as a personal computer or a communication home appliance connected to the user network can communicate with the Internet via the lower PON, the upper PON, and the upper network.

The master station device 10 is installed in a telecommunications carrier's facility, and is also connected to a “management network” for the telecommunications carrier to manage the master station device.
Therefore, the communication carrier can perform a predetermined setting operation for network management on the master station device 10 using a terminal device such as a personal computer connected to the management network. However, the terminal device in this case may be directly connected to the master station device 10.

  When the PON line L1 is shortened and installed in the telecommunications carrier's facility, the relay device 20 is similar to the master station device 10, such as a personal computer directly connected to the relay device 20 via the management network. A predetermined setting operation for network management of the relay device 20 can be performed using the terminal device.

However, when the PON line L1 has a normal transmission distance of kilometer order and each relay device 20 is a remote station away from the management network, the setting work by the terminal device connected to the management network or the relay device 20 is performed. I can't do it.
Therefore, even when the relay device 20 is a remote station, it is desirable that settings for network management can be performed for the relay device 20 and the slave station devices 30 under the control network connected to the master station device 10. Measures for solving the problem will be described later.

[Configuration of master station device]
FIG. 2 is a block diagram illustrating the configuration of the master station device 10.
As shown in FIG. 2, the master station device 10 includes, in order from the upper side (upper side in FIG. 2) to the lower side, the upper side receiving unit 101, the upper side transmitting unit 102, the data relay processing unit 103, the control signal processing. Unit 104, PON transmitter 105, PON receiver 106, optical transmitter (E / O converter) 107, optical receiver (O / E converter) 108, and multiplexer / demultiplexer 109.
Further, the master station device 10 includes an OLT function control unit 110 that can be connected to a terminal device of a communication carrier for network setting via a management network or a setting port P1.

In FIG. 2, a downlink data frame from the upper network is received by the upper receiving unit 101 and sent to the data relay processing unit 103.
The data relay processing unit 103 passes the downstream data frame to the PON transmission unit 105, and this frame is converted into a downstream optical signal having the wavelength λ2 and the transmission rate R2 [Gbps] by the optical transmission unit 107, and the multiplexing / demultiplexing unit 109 is sent to the PON line L1.

The upstream optical signal having the wavelength λ1 and the transmission rate R1 [Gbps] transmitted from the relay apparatus (FIG. 3) of the PON line L1 passes through the multiplexing / demultiplexing unit 109 and reaches the optical receiving unit 108. .
The optical receiving unit 108 includes a photoelectric conversion element that converts the received optical signal into an electric signal, and an amplifier that amplifies the converted electric signal. The electric signal amplified by the amplifier is sent to the PON receiving unit 106. Entered.

The PON receiving unit 106 performs processing such as clock and data reproduction, decoding at the physical layer, and reproduction of an Ethernet frame (“Ethernet” is a registered trademark) on the input electric signal.
The PON receiving unit 106 reads the header portion of the reproduced upstream frame and determines whether the received frame is a data frame or a control frame such as a report frame.

Examples of the control frame include, for example, an MPCP (Multi-Point Control Protocol) frame and an OAM (Operation Administration and Maintenance) frame defined by IEEE Std 802.3 ^™ -2008.
“Grant” in which the master station device 10 instructs the relay device 20 on the transmission start time and the permitted transmission amount of the uplink data, or the relay device 20 notifies the master station device 10 of a value related to the accumulated amount of uplink data “ “Report” is a kind of MPCP frame.

As a result of the determination, if the received frame is a data frame, the PON receiving unit 106 sends the frame to the data relay processing unit 103. The data relay processing unit 103 performs predetermined relay processing such as change of header information of the data frame and transmission control for the higher-level transmission unit 102, and the processed frame is transmitted from the higher-level transmission unit 102 to the higher-level network.
As a result of the determination, if the received frame is a report frame, the PON receiving unit 106 transfers the frame to the control signal processing unit 104.

Based on the report frame, the control signal processing unit 104 performs uplink bandwidth allocation (DBA: Dynamic Bandwidth Allocation) with a predetermined control logic.
In addition, the control signal processing unit 104 generates a grant frame in which the transmission permission amount calculated as a result of DBA and the LLID (Logical Link ID) of the transmission source relay device 20 are written, and puts them in the PON transmission unit 105. The grant frame is converted into a downstream optical signal having a wavelength λ2 and a transmission rate R2 [Gbps] in the optical transmission unit 107, and is transmitted from the multiplexing / demultiplexing unit 109 to the PON line L1.

The OLT function control unit 110 of the master station device 10 transmits a “management command” for operation, maintenance or management (hereinafter abbreviated as “maintenance management”) to each device constituting the first communication network. Or from the setting port P1. This maintenance management interface of the master station is called a command line interface.
When the OLT function control unit 110 receives a predetermined command from the telecommunications carrier's terminal device via the management network or the like, the OLT function control unit 110 performs processing according to the command and sends a response describing the result of this processing to the telecommunications carrier. To the terminal device.

The above management command is communication established by virtual terminal software such as SSH (Secure Shell) for performing encryption communication for preventing eavesdropping (peeping) on a route, for example, Telnet (Telecommunication network). It is communicated via a remote session with the operator's terminal. In the present embodiment, the following two types of terms are defined.
1) Management command: A command for maintaining and managing a specific PON, which is input from the communication device terminal device to the “master station” or “master station equivalent” via the command line interface. In FIG. 1, the master station function units 21 of the master station device 10 and the relay device 20 correspond to “master station” and “master station equivalent unit”, respectively.

  2) Management frame: “slave station” or “slave station equivalent part” input from the “master station” or “slave station equivalent part” to the “slave station” or “slave station equivalent part” of the PON via the PON interface A frame for maintenance management. In FIG. 1, the slave station function unit 22 and the slave station device 30 of the relay device 20 correspond to “slave station equivalent unit” and “slave station”, respectively.

When the OLT function control unit 110 receives the management command, the OLT function control unit 110 performs setting and processing for maintenance management on each of the units 101 to 106 in the master station device 10 according to the management command.
For example, according to the management command, the OLT function control unit 110 performs settings related to the flow control of the higher-level receiving unit 101, settings related to transmission rate shaping of the higher-level transmission unit 102, settings related to the queue of the data relay processing unit 103, and frame conversion. Settings are made, settings related to DBA operation parameters of the control signal processing unit 104, settings related to encryption modes and operation timings of the PON transmission unit 105 and the PON reception unit 106, and the like. Moreover, the state of each part in the apparatus is acquired, and a response is returned to the terminal of the communication carrier.

  Further, the OLT function control unit 110 performs setting and processing for its own maintenance management. For example, the device or module is restarted, the master station device clock is set, the management port IP address is set, the device version is displayed, the device status is displayed, the alarm is displayed, and the log information is displayed.

  When receiving the management command management command for the slave station connected to the first communication network, the OLT function control unit 110 passes the management command to the control signal processing unit 104. Based on the management command, the control signal processing unit 104 assembles a management frame for the slave station 30 or the relay device 20 of the first communication network that is the object of maintenance management, and puts it in the PON transmission unit 105.

Then, the management command is converted into a downstream optical signal having a wavelength λ2 and a transmission rate R2 [Gbps] in the optical transmission unit 107, and is transmitted from the multiplexing / demultiplexing unit 109 to the PON line L1.
Examples of management commands for slave stations connected to the first communication network (such as the slave station function unit 21 of the relay device 20 and the slave station device 30) are logical link disconnection with the slave station, reset of the slave station, slave station Loopback test, setting related to the queue of the slave station, setting related to the frame conversion rule in the slave station, display of the status and setting contents of the slave station, and the like.

The control signal processing unit 104 generates and transmits / receives an OAM frame that is managed by the relay device 20 of the upper PON, and this OAM frame includes a normal OAM frame defined in IEEE802.3-2008 Clause57, There is an extended OAM frame uniquely defined for the purpose of maintenance management by a telecommunications carrier.
When the registration of the relay device 20 is completed by discovery in the upper PON, the control signal processing unit 104 establishes an OAM link via a logical link with the relay device 20. If there is an instruction by the management command, an OAM loopback test is performed with a specific relay device 20.

When the OLT function control unit 110 receives a management command for requesting establishment of a communication session in the control-system communication path for the master station function unit 22 of the relay device 20, the relay that is targeted for maintenance management based on the management command A frame requesting the apparatus 20 to establish a communication session is assembled and passed to the data relay processing unit 103.
The data relay processing unit 103 transmits the assembled frame via the PON transmission unit 105 and relays the response to the OLT function control unit 110 via the data relay processing unit 103 if there is a response from the relay device.

The OLT function control unit 110 receives the response and, if necessary, further establishes a session by exchanging a predetermined frame with the master station function unit 22 of the relay apparatus 20. This series of frame exchanges is performed in the virtual control system communication path shown in FIG. By this procedure, it becomes possible to access the command line interface for the master station function unit 22 of the relay apparatus 20 from the management network via the control system communication path.
The communication carrier uses the command line interface of the master station function unit 22 of the relay device 20 to maintain and manage the slave station device 30 connected to the second communication network.

[Configuration of relay device]
FIG. 3 is a block diagram illustrating a configuration of the relay device 20.
As shown in FIG. 3, the relay device 20 generally includes a slave station function unit 21 on the upper side (upper side in FIG. 3), a master station function unit 22 on the lower side, and these function units 21 and 22. And a data distribution unit 23 between them. The data distribution unit 23 is composed of, for example, an L2 switch.
In addition, the relay device 20 includes a device control unit 24 for network setting that can be connected to a terminal device of a communication carrier via a virtual control system communication path in the upper PON or a setting port P2. .

  Among the functional units 21 and 22, the slave station functional unit 21 is a functional part that constitutes the ONU of the upper stage PON, and in order from the upper side to the lower side, the multiplexing / demultiplexing unit 201, the optical receiving unit (O / E converter) 202, optical transmitter (E / O converter) 203, PON receiver 204, PON transmitter 205, control signal processor 206, data relay processor 207, data transmitter 208, data receiver 209 and An ONU function control unit 210 is provided.

In FIG. 3, the optical signal transmitted in the downstream direction from the master station device 10 passes through the multiplexing / demultiplexing unit 201 and is converted into an electrical signal by the optical receiving unit 202, and this electrical signal is converted into the PON receiving unit 204. Received by.
The PON receiving unit 204 reads the header portion (including the preamble portion) of the received frame, and means that the frame is addressed to itself (in this case, addressed to itself or the slave station 30 under its control or broadcast. ).

As a result of the determination, if it is addressed to itself, the PON receiving unit 204 takes in the frame, and if not, discards the frame.
For example, as an example of the header information for performing the destination determination, a logical link identifier (LLID) described in IEEE standard 802.3-2008 can be given.

Furthermore, the PON receiving unit 204 determines whether the received frame is a data frame or a control frame by reading the header portion of the frame.
As a result of the determination, if the received frame is a data frame, the PON receiving unit 204 sends the frame to the data relay processing unit 207. The data relay processing unit 207 performs predetermined relay processing such as transmission control on the data transmission unit 208, and the processed frame is input to the data distribution unit 23.

  As a result of the determination, if the received frame is a control frame, the PON reception unit 204 transfers the frame to the control signal processing unit 206. The control signal processing unit 206 performs processing based on the content of the control frame. For example, if the control frame is a grant frame indicating permission for transmission in the uplink direction, the control signal processing unit 206 instructs the data relay processing unit 207 on the transmission timing and data amount in the uplink direction based on the grant frame.

The data frame output by the data distribution unit 23 in the upstream direction is received by the data reception unit 209 and transferred to the data relay processing unit 207.
The transferred data frame is temporarily stored in the buffer memory in the data relay processing unit 207, and the uplink data amount is notified to the control signal processing unit 206. The control signal processing unit 206 performs transmission control on the PON transmission unit 205 and causes the PON transmission unit 205 to output an upstream data frame stored in the buffer memory at a predetermined timing.

Further, the control signal processing unit 206 creates a report frame based on the notified data storage amount in the buffer memory, and causes the PON transmission unit 205 to output the report frame.
The upstream frame output from the PON transmission unit 205 is converted into an upstream optical signal having a wavelength λ1 and a transmission rate R1 by the optical transmission unit 203 and transmitted from the multiplexing / demultiplexing unit 201 to the PON line L1.

In this embodiment, transmission in the upstream direction on at least the PON line L2 is performed as an upstream buffer (for example, a plurality of queues having different priorities when a transmission right is obtained) of the data relay processing unit 207 of the slave station function unit 21. It is preferable to employ a rate having a buffer capacity that is obtained by multiplying the rate R3 by the maximum time required from report transmission through the PON line L1 to grant reception.
If the transmission rate R1 (= 10G) of the upstream optical signal in the upper PON is higher than the transmission rate R3 (= 1G) of the upstream signal in the lower PON, the number of branches in the upper PON can be increased. Thus, it is possible to effectively secure the upstream bandwidth per user.

Further, in the present embodiment, as a downlink buffer (for example, a plurality of queues having different priorities when obtaining a transmission right) of the data relay processing unit 207 of the slave station function unit 21, a predetermined time (the master station is each slave station) It is preferable to employ one having a buffer capacity that can absorb the difference between the transmission rates R2 and R4 in the downstream direction on the PON lines L1 and L2 over a period of time during which transmission is continued.
If the transmission rate R2 (= 10G) of the downstream optical signal in the upper PON is higher than the transmission rate R4 (= 1G) of the downstream signal in the lower PON, the number of branches in the upper PON can be increased. Thus, it is possible to effectively secure the downstream bandwidth per user.

  Of the functional units 21 and 22 installed in the relay apparatus 20, the master station functional unit 22 is a functional part that constitutes the OLT of the lower PON, and the data receiving unit 211, data A transmission unit 212, a data relay processing unit 213, a control signal processing unit 214, a PON transmission unit 215, a PON reception unit 216, an optical transmission unit (E / O conversion unit) 217, an optical reception unit (O / E conversion unit) 218, A multiplexing / demultiplexing unit 219 and an OLT function control unit 220 are provided.

In FIG. 3, the downlink data frame output by the data distribution unit 23 in the downlink direction is received by the data reception unit 211 and sent to the data relay processing unit 213.
The data relay processing unit 213 passes the downstream data frame to the PON transmission unit 215, and this frame is converted by the optical transmission unit 217 into a downstream optical signal having the wavelength λ4 and the transmission rate R4 [Gbps]. 219 is sent to the PON line L2.

The upstream optical signal having the wavelength λ3 and the transmission rate R3 [Gbps] transmitted from the slave station apparatus (FIG. 4) of the PON line L2 passes through the multiplexing / demultiplexing unit 219 and reaches the optical receiving unit 218. To do.
The optical receiving unit 218 includes a photoelectric conversion element that converts the received optical signal into an electric signal, and an amplifier that amplifies the converted electric signal. The electric signal amplified by the amplifier is sent to the PON receiving unit 216. Entered.

The PON receiving unit 216 performs processing such as clock and data reproduction, physical layer decoding, and Ethernet frame reproduction on the input electrical signal.
The PON receiving unit 216 reads the header portion of the reproduced upstream frame and determines whether the received frame is a data frame or a control frame such as a report frame.

As in the case of the master station device 10, examples of the control frame include an MPCP frame and an OAM frame.
The “grant” in which the master station function unit 22 of the relay device 20 instructs the slave station device 30 to start transmission of uplink data and the transmission permission amount, or the slave station device 30 sends the master station function unit 22 of the relay device 20 to the master station function unit 22. A “report” for notifying a value related to the amount of accumulated uplink data is a type of MPCP frame.

As a result of the determination, if the received frame is a data frame, the PON receiving unit 216 sends the frame to the data relay processing unit 213. The data relay processing unit 213 performs predetermined relay processing such as change of header information of the data frame and transmission control for the data transmission unit 212, and the processed frame is input from the data transmission unit 212 to the data distribution unit 23.
As a result of the determination, if the received frame is a report frame, the PON reception unit 216 transfers the frame to the control signal processing unit 214.

The control signal processing unit 214 performs uplink band allocation (DBA) with a predetermined control logic based on the report frame.
In addition, the control signal processing unit 214 generates a grant frame in which the transmission permission amount calculated as a result of the DBA and the LLID of the transmission source slave station device 30 are written, and puts them in the PON transmission unit 215. The grant frame is converted into a downstream optical signal having a wavelength λ4 and a transmission rate R4 [Gbps] by the optical transmission unit 217, and is transmitted from the multiplexing / demultiplexing unit 219 to the PON line L2.

The control signal processing unit 214 also generates and transmits / receives an OAM frame that is managed by the slave station device 30 in the lower PON.
Examples of the OAM frame include a normal OAM frame defined in Clause 57 of IEEE 802.3-2008, and an extended OAM frame uniquely defined for the purpose of maintenance management by a communication carrier.

  When the registration of the slave station device 30 is completed by discovery in the lower PON, the control signal processing unit 214 establishes an OAM link via a logical link with the slave station device 30. If there is an instruction by the management command, an OAM loopback test is performed.

[Maintenance management for the slave station function section of the relay device]
Maintenance management for the slave station function unit 21 of the relay apparatus 20 is performed by the normal OAM frame or the extended OAM frame generated by the master station apparatus 10. These OAM frames are terminated in the control signal processing unit 206 or the ONU function control unit 210 and do not reach the data distribution unit 23. Therefore, the OAM frame is not relayed to the external port that the ONU has.
That is, when the received frame is an OAM frame, the PON receiving unit 204 passes the frame to the control signal processing unit 206 or the ONU function control unit 210.

When the control signal processing unit 206 acquires an OAM frame, the control signal processing unit 206 performs predetermined maintenance management processing according to the content of the frame.
For example, when the control signal processing unit 206 acquires a loopback establishment request for a normal OAM frame, the control signal processing unit 206 returns a loopback establishment response to the master station device 10 and then receives a loopback test execution request. Is returned to the master station device 10.

  In addition, when the control signal processing unit 206 acquires the extended OAM frame, the control signal processing unit 206 passes the frame to the ONU function control unit 210, and the ONU function control unit 210 performs a predetermined maintenance management process according to the content to the slave station function. The processing is performed on each of the units 204 to 209 in the unit 21, and the processing result is returned to the master station device 10 via the control signal processing unit 206.

[Maintenance management for the relay station master station function]
Maintenance management for the master station function unit 22 of the relay device 20 is performed by a management command sent via the above-mentioned “virtual control system communication path” (see FIG. 7). Since this management command is stored and transferred in a data frame having no control frame format such as an OAM frame or an MPCP frame, the PON receiving unit 204 handles it as a data frame. Therefore, the data frame storing the management command is input to the data distribution unit 23 via the data relay processing unit 207 and the data transmission unit 208.

The data distribution unit 23 determines whether the downstream data frame is a data frame including a management command or another data frame, and distributes an output destination according to the determination result.
That is, in the case of a data frame including a management command, the data distribution unit 23 passes it to the device control unit 24, and in the case of other data frames, the data reception unit 211 of the master station function unit 22 To pass. This distribution is also a process of determining whether or not the frame has passed through the control communication channel. For example, based on the destination MAC address in the frame, the combination of the destination MAC address and the source MAC address, the VLAN ID, and the like. It can be carried out.

The device control unit 24 reads the processing content described in the management command and issues a maintenance management command to the OLT function control unit 220.
The OLT function control unit 110 performs setting and processing for maintenance management on the units 211 to 216 in the master station function unit 22 of the relay device 20 according to the command.

  For example, the OLT function control unit 220, in accordance with the above command, the setting related to the flow control of the data reception unit 211, the setting related to the shaping of the transmission rate of the data transmission unit 212, the setting related to the queue and the frame conversion of the data relay processing unit 213, Settings related to the DBA operation parameters of the control signal processing unit 214 and settings related to the encryption mode and operation timing of the PON transmission unit 215 and the PON reception unit 216 are performed. Also, the status of each part in the apparatus is acquired and a response is returned to the apparatus control unit 24.

The OLT function control unit 220 returns a response to the apparatus control unit 24 if a response as a result of the maintenance management is necessary.
Upon receiving the response, the device control unit 24 generates a response frame that stores part or all of the response content, and inputs this response frame to the data distribution unit 23. Since this response frame is handled as a data frame in the data relay processing unit 207, it is sent to the PON line L1 and returned to the master station device 10.
The device control unit 24 also performs setting and processing for maintenance management of the relay device. For example, the device or function block is restarted, the device clock is set, the management port IP address is set, the device version is displayed, the device status is displayed, the alarm is displayed, or the log information is displayed.

As described above, in the optical communication system according to the present embodiment, the master station device 10 connected to the management network sets the control communication channel with the relay device 20, thereby maintaining and managing the data in a format different from the OAM frame. Can be exchanged with the device control unit 24 of the relay device 20 which is a remote station.
In the relay device 20 of FIG. 3, maintenance management of the master station function unit 22 can also be performed from a terminal device connected to the setting port P2 of the device control unit 24.

[Configuration of slave unit]
FIG. 4 is a block diagram illustrating a configuration of the slave station device 30.
As illustrated in FIG. 4, the slave station device 30 includes a multiplexing / demultiplexing unit 301, an optical receiving unit (O / E converting unit) 302, and an optical transmitting unit in order from the upper side (upper side in FIG. 4) to the lower side. (E / O converter) 303, PON receiver 304, PON transmitter 305, control signal processor 306, data relay processor 307, user side transmitter 308, user side receiver 309 and ONU function controller 310 ing.

In FIG. 4, the optical signal transmitted in the downstream direction from the relay apparatus 20 passes through the multiplexing / demultiplexing unit 301 and is converted into an electrical signal by the optical receiving unit 302, and this electrical signal is converted by the PON receiving unit 304. Received.
The PON receiving unit 304 reads the header portion (including the preamble portion) of the received frame to determine whether the frame is addressed to itself.

As a result of the determination, if it is addressed to itself, the PON receiving unit 304 takes in the frame, and if not, discards the frame.
For example, LLID described in IEEE standard 802.3-2008 can be given as an example of header information for performing the above destination determination.

Furthermore, the PON receiving unit 304 determines whether the received frame is a data frame or a control frame by reading the header portion of the frame.
As a result of the determination, if the received frame is a data frame, the PON receiving unit 304 sends the frame to the data relay processing unit 307. The data relay processing unit 307 performs predetermined relay processing such as transmission control for the user-side transmission unit 308, and the processed frame is transmitted to the user network.

  As a result of the determination, if the received frame is a control frame, the PON receiving unit 304 transfers the frame to the control signal processing unit 306. The control signal processing unit 306 performs processing based on the content of the control frame. For example, if the control frame is a grant frame indicating permission for transmission in the upstream direction, the data relay processing unit 307 is instructed based on the grant frame for transmission timing and data amount in the upstream direction.

The upstream data frame from the user network is received by the user-side receiving unit 309 and transferred to the data relay processing unit 307.
The transferred data frame is temporarily stored in the buffer memory in the data relay processing unit 307 and the uplink data amount is notified to the control signal processing unit 306. The control signal processing unit 306 performs transmission control on the PON transmission unit 305 and causes the PON transmission unit 305 to output an upstream data frame stored in the buffer memory at a predetermined timing.

Further, the control signal processing unit 306 creates a report frame based on the notified data storage amount in the buffer memory, and causes the PON transmission unit 305 to output the report frame.
The upstream frame output from the PON transmission unit 305 is converted into an upstream optical signal having a wavelength λ3 and a transmission rate R3 by the optical transmission unit 303, and is transmitted from the multiplexing / demultiplexing unit 301 to the PON line L2.

[Maintenance management for slave unit]
Maintenance management for the slave station device 30 is basically the same as the maintenance management performed by the master station device 10 of the upper PON for the slave station function unit 21 of the relay device 20. Specifically, the maintenance management is performed by the normal OAM frame and the extended OAM frame generated by the master station function unit 22 of the relay device 20.
That is, if the received frame is an OAM frame, the PON receiving unit 304 passes the frame to the control signal processing unit 306.

When the control signal processing unit 306 acquires an OAM frame, the control signal processing unit 306 performs predetermined maintenance management processing according to the content of the frame.
For example, when the control signal processing unit 306 acquires a loopback establishment request for a normal OAM frame, the control signal processing unit 306 returns a loopback establishment response to the relay apparatus 20, and then receives a loopback test execution request and returns a predetermined test result. The response frame of the loopback test described is returned to the relay device 20.

  Further, when the control signal processing unit 306 acquires the extended OAM frame, the control signal processing unit 306 passes the frame to the ONU function control unit 310, and the ONU function control unit 310 performs a predetermined maintenance management process according to the content of the self-device 30. The processing results are returned to the relay device 20 via the control signal processing unit 306.

Here, since the OAM frame transmitted from the slave station device 30 to the relay device 20 is terminated by the control signal processing unit 214 (see FIG. 3) of the master station function unit 22 in the relay device 20, the OAM frame is transmitted to the data distribution unit 214. Will not reach. The upstream OAM frame transmitted from the slave station device 30 is terminated at the relay device and is not relayed to the external port of the relay device 20.
Accordingly, the information obtained by the relay device 20 transmitting / receiving the OAM frame with the subordinate station device 30 (hereinafter referred to as “OAM information”) is transmitted to the master station device 10 in the received OAM frame format. You will not be notified.

Therefore, in the present embodiment, the OAM information of the slave station device 30 is reported to the master station device 10 using the management command described above.
That is, referring to FIG. 3, when the control signal processing unit 214 of the master station function unit 22 acquires the OAM information of the slave station device 30 by transmitting and receiving an OAM frame, the acquired OAM information is transferred to the OLT function control unit 220. The data is passed to the device control unit 24.

When acquiring the OAM information, the device control unit 24 generates a management frame response including a part or all of the information, and inputs the response frame to the data distribution unit 23.
Since the response frame including the OAM information is handled as a data frame by the data relay processing unit 207, the response frame is transmitted to the PON line L1 and returned to the master station device 10.

Referring to FIG. 2, the response frame that has arrived at master station device 10 is input to data relay processing unit 103 via optical receiving unit 108 and PON receiving unit 106.
The response frame input to the data relay processing unit 103 is transferred to the OLT function control unit 110 and transmitted to the terminal device of the communication carrier connected to the management network or the setting port P1.

[Attaching tag information to data frames]
By the way, the SLA, which is an agreement regarding the service level between the service provider (telecom carrier) and the user, includes provisions relating to QoS, and is generally related to charging for the user. .
For example, “minimum guaranteed bandwidth”, “maximum allowable bandwidth”, “maximum delay time”, “maximum delay time fluctuation”, “maximum frame loss rate”, “maximum service interruption time”, etc. in the data transfer section are QoS indicators. obtain.

In some cases, a QoS index is defined according to traffic for each data type such as telephone, broadcast, and data communication.
Therefore, it is desirable that the QoS of communication provided to users of the communication service satisfies the SLA, and it is desirable that the QoS of communication provided is fair according to the SLA for each user. In other words, it is desirable for the users who have contracted with the same SLA to provide the same QoS.

Alternatively, it is desirable that a user who has contracted with a more advantageous SLA be provided with a better QoS than other users who have contracted with a more disadvantageous SLA. Here, an index indicating quality of QoS and an index indicating fairness need to be defined separately.
If the master station device 10 cannot identify the user network of the transmission source of each frame or the slave station device 30 of the transmission source, QoS control of communication between the user network and the upper network and fairness of QoS between users are performed. It is not possible to perform control to maintain the thickness.

Here, “fair” means providing QoS according to the consideration. It is fair to provide better services to users who pay high usage fees, and it is not fair to provide the same QoS to all users regardless of the usage fee.
Therefore, in order to achieve QoS satisfying the SLA of the slave station device 30, as a premise, which slave station device 30 is the transmission source in the lower PON of the upstream data frame acquired from the relay device 20 is assumed. It is necessary to grasp.

  As shown in FIG. 1, in a system in which PONs are hierarchically connected via the relay device 20 and the upstream multiple access control of the upper PON and the upstream multiple access control of the lower PON are performed independently, the slave station device 30 does not establish a direct link with the master station device 10, and if no measures are taken, the master station device 10 specifies which slave station device 30 is the source of the upstream data frame. Can not.

  In this regard, in the case of an Ethernet frame, the transmission source can be specified by the MAC address field, but the MAC address of the slave station device 30 is not stored in the Ethernet frame relayed from the user network such as a MAC bridge. There exists such a frame relay method.

  In the relay method in which the MAC address of the slave station device 30 is stored in the relayed Ethernet frame, the MAC address has a long data length of 48 bits and is independent of the network connection configuration. Therefore, in order to specify the transmission source using the MAC address as a search key, for example, special means such as a search circuit using a CAM (Content Addressable Memory) is necessary. Become.

For example, in the optical communication system of the present embodiment shown in FIG. 1, when the number of branches of the upper and lower PONs is 32, the total number of branches of the entire system is 32 × 32 = 1024, and a long data area of 48 bits. Even if the slave station device 30 is not used, the slave station device 30 can be sufficiently identified.
Therefore, in the present embodiment, the relay device 20 identifies the transmission source child station device 30 in the upstream data frame received from the lower PON so that the QoS of the child station device 30 can be appropriately controlled. Is transferred to the upper PON.
Specifically, for example, the data relay processing unit 213 of the relay device 20 writes the tag information in an upstream data frame.

The master station device 10 uses the value of the tag information written in the uplink data frame to count the amount of uplink traffic for each slave station device 30 or counts for each priority for each slave station device. Based on the aggregated data, the QoS for the slave station device 30 is controlled.
For example, the data relay processing unit 103 of the master station device 10 determines that the child station device 30 specified by the tag information value does not satisfy the QoS set in the slave station device 30 when the traffic volume is not satisfied. The DBA is operated so that the upstream bandwidth is preferentially assigned to the station device 30.

Or, when a surplus bandwidth remains after assigning a bandwidth for transmitting high-priority traffic to all the slave station devices 30 performing uplink communication, the slave station device 30 requested A surplus bandwidth can also be allocated to the slave station device 30 that could not satisfy the bandwidth according to the ratio of the difference between the minimum guaranteed bandwidth and the allocated bandwidth.
Alternatively, when a surplus bandwidth remains after assigning the minimum guaranteed bandwidth to all the slave station devices 30 performing uplink communication, the bandwidth requested from the slave station device 30 cannot be satisfied. The surplus bandwidth can also be allocated to the slave station device 30 in accordance with the ratio of the minimum guaranteed bandwidth.

Alternatively, when a surplus bandwidth remains after assigning the minimum guaranteed bandwidth to all the slave station devices 30 performing uplink communication, the bandwidth requested from the slave station device 30 cannot be satisfied. The surplus bandwidth can also be assigned to the slave station device 30 in accordance with the ratio of the difference between the maximum allowable bandwidth and the minimum guaranteed bandwidth.
Alternatively, when a surplus bandwidth remains after assigning the minimum guaranteed bandwidth to all the slave station devices 30 performing uplink communication, the bandwidth requested from the slave station device 30 cannot be satisfied. It is also possible to assign the surplus bandwidth to the slave station devices 30 in order until the maximum allowable bandwidth is reached.

FIG. 5 is a diagram illustrating an example of the frame format of the uplink data frame.
FIG. 5A shows a normal data frame before tag information is added, and FIG. 5B shows a data frame when only tag information T1 for a slave station device is added.
FIG. 5C shows a data frame when two types of tag information T1 and T2 for the slave station device and the relay device are added.

As shown in FIG. 5B, when only the tag information T1 for the slave station device is attached to the data frame, the relay device 20 uses, for example, the logical link number (LLID) of the slave station device 30 assigned in MPCP. The value of the tag information T1 is determined based on the value of.
That is, the relay device 20 holds the value of the tag information T1 for each logical link number of the slave station device 30 used in the lower PON, and writes the value in a predetermined area of the upstream data frame.

The writing of the tag information T1 may be overwritten on a field already in the frame or may be written in a newly provided field according to the format of the data frame.
In this case, the master station device 10 uses a combination of one type of tag information T1 included in the upstream data frame and the logical link number of the relay device 20 in the upper stage PON, and the slave station device that is the transmission source of the data frame 30 can be uniquely identified.

  However, it is possible to uniquely identify the slave station device 30 using only the tag information T1 for the slave station device without using the logical link number. In this case, if different relay devices 20 use the same tag information T1, the different slave station devices 30 are actually treated as the same slave station device, and the master station device 10 has a traffic volume for each slave station device 30. Therefore, it is preferable to notify or set the relay device 20 in advance so that tag information values used by the respective relay devices 20 do not overlap.

As shown in FIG. 5C, when two types of tag information T1 and T2 for the slave station device and the relay device are added to the data frame, the relay device 20 is notified from the master station device 10 in advance. Tag information T2 is written in the data frame together with the tag information T1.
The tag information T2 may be written in the field already existing in the frame or may be written in a newly provided field according to the data frame format.

In this case, the master station device 10 can uniquely specify the slave station device 30 that is the transmission source of the data frame by a combination of the two types of tag information T1 and T2 included in the upstream data frame.
Thus, when two types of tag information T1 and T2 are given, the slave station device 30 can be uniquely identified by the values of the two types of tag information T1 and T2 without using the logical link number. It is not necessary to perform notification or setting for the relay device 20 so as not to duplicate the tag information T1 value for the slave station device.

The master station device 10 controls the amount of traffic to the upper network according to the SLA set for each slave station device 30. For example, if there is a surplus bandwidth after allocating the bandwidth for the minimum guaranteed bandwidth defined in the SLA to the slave station device 30 performing communication, the surplus bandwidth is subsidized according to the ratio of the maximum guaranteed bandwidth. Control to allocate to the station apparatus 30 is performed.
In association with the slave station device 30 and the SLA in the master station device 10, the SLA for each slave station device 30 is set in the master station device 10 in association with the combination of the tag information T1 and the logical link number of the upper PON. be able to.

Alternatively, the SLA for each slave station device 30 can be set in the master station device 10 in association with the set of tag information T1 and T2. Alternatively, when T1 is not duplicated in the system, the SLA for each slave station device 30 can be set in the master station device 10 in association with the tag information T1.
Note that the master station device 10 may rewrite or delete the tag information T1 and T2 when transferring the upstream data frame to the upper network.

Specifically, the uplink transmission scheduling (bandwidth allocation) by the master station device 10 is performed as follows, for example.
The master station device 10 has a plurality of queues corresponding to the priority of the upstream frame, and queues the upstream frame to one of the plurality of queues based on the priority of the frame. Then, the master station device 10 transmits to the higher-level network side from frames queued in a high priority queue, or sequentially transmits frames from non-empty queues according to the weight distribution provided for each queue. To do. Alternatively, there is a method for determining the transmission order by combining them.

The priority of a data frame can be determined from a particular field in the frame, for example. The Tos field in the IPv4 frame header, the TC field in the IPv6 frame header, or the PCP field defined in IEEE Std 802.1Q ^TM -2011 corresponds to the specific field.
The master station device 10 can refer to the priority field in these frames and distribute the frames to the priority queues for each slave station device 30, and perform uplink transmission scheduling for each priority queue. Can do.

  In this case, for example, priority can be divided for each data type such as telephone, broadcast, data communication, etc., and high priority can be assigned to delay-sensitive telephone traffic to relay telephone traffic with priority. .

[Effect of optical communication system]
As described above, according to the optical communication system of the present embodiment, the uplink device 20 receives the uplink frame transmitted from the own device according to the uplink multiple access control performed by the master station device 10. As for frame reception, uplink multiple access control is performed independently. Therefore, as shown in FIG. 1, an upper stage PON that connects a plurality of relay devices 20 with a single master station device 10 as a vertex, and a subordinate of the relay device 20 In addition, it is possible to configure a multi-stage optical communication system that further includes a lower stage PON that connects a plurality of slave station devices 30.

For this reason, since the transmission distance peculiar to the PON is a value obtained by adding the upper PON and the lower PON, the distance between the master station device 10 and the slave station device 30 can be increased.
Further, since the number of branches unique to the PON is a value obtained by multiplying the amount of the upper PON and the amount of the lower PON, the number of branches in the entire optical communication system can be increased.

Moreover, even if the number of lower PONs increases, the cost of the entire optical communication system can be reduced because only one master station device 10 is sufficient. In this case, since only one interface with the host network of the master station device 10 is sufficient, the cost of the entire optical communication system including the host network can be suppressed.
Furthermore, since only one relay device 20 is required per one lower stage PON, the cost of the entire optical communication system can be suppressed from this point.

On the other hand, in the multi-rate PON in which 10G and 1G transmission rates are mixed as in the above-mentioned Patent Document 2, the link throughput when transmission is performed at 1G is only time division multiplexing with the maximum transmission rate of 10G. It is smaller than the throughput of the link when accessing.
For example, in the case of the multi-rate PON, when the time division multiplexing of half time is 10G and the other half time is 1G, the link throughput in this case is 5,5 Gbps, and the total time is 10G. It is smaller than the throughput of a link that is time-division multiplexed.

  In this regard, the optical communication system according to the present embodiment has a hierarchical structure in which the upper PON is set to 10G-EON and the lower PON is set to 1G-EPON. Therefore, patent documents in which uplink transmission rates are mixed in one PON. Compared with the multi-rate PON of No. 2, there is an advantage that the bandwidth utilization efficiency in the upstream direction of the entire system can be improved.

According to the optical communication system of the present invention, the relay apparatus 20 adds tag information T1 and T2 (only T1 may be used) to the upstream data frame, and the master station apparatus 10 includes the tag information included in the data frame. Based on T1 and T2 (only T1 may be used), the amount of uplink traffic is aggregated for each slave station device 30 or for each priority for each slave station device.
Therefore, the master station device 10 can set the QoS corresponding to the SLA corresponding to the aggregated traffic amount for each slave station device 30, and can surely achieve the SLA of the slave station device 30 in the lower PON.

Further, according to the optical communication system of the present invention, the master station device 10 can set up a virtual control system communication path and can transmit / receive a management data frame having a format different from that of the OAM to / from the relay device 20. When the relay device 20 receives a management frame message from the master station device 10, a response of the management data frame including the OAM information obtained by transmitting / receiving the OAM frame with the slave station device 30 is The data is transmitted to the master station device 10.
For this reason, maintenance management of the slave station device 30 in the lower PON can be easily performed from the master station device 10 in the upper PON.

[Modification of relay device]
FIG. 6 is a block diagram illustrating a modified example of the relay device 20.
The relay device 20 according to the modification shown in FIG. 6 is different from the relay device 20 (FIG. 3) according to the above-described embodiment in that the device control unit 24 is also connected to the ONU function control unit 210. In accordance with the management command acquired from 10, a maintenance management command can be issued to the ONU function control unit 210.

That is, in this case, the master station device 10 can also include setting information of the slave station function unit 21 responsible for the slave station function of the relay device 20 in the management command.
Further, the device control unit 24 of the relay device 20 issues a slave station function setting process command to the ONU function control unit 210 in accordance with the setting information included in the management frame.

  Therefore, if the relay device 20 according to the modification is employed, remote operation via the master station device 10 can be used for setting of the slave station function of the relay device 20 that cannot be performed with the OAM frame transmitted / received to / from the master station device 10. Will be able to.

On the contrary, if the relay device 20 according to the modification is employed, a maintenance management command is issued from the ONU function control unit 210 to the device control unit 24 using an OAM frame transmitted / received to / from the master station device 10. You can also
For this reason, for example, even if the relay device 20 is initially installed, operations such as setting of a network address such as an IP address are performed remotely on the device control unit 24 via the master station device 10. Can do. Note that a network address such as an IP address may not be set in the relay device 20 at the time of installation. In this case, a session such as Telnet or SSH may be established in a virtual control communication channel. Can not. Therefore, when the relay device 20 according to the modification is not employed, it is necessary to set a network address from the setting port P2 at the installation location.

[Other variations]
The scope of right of the present invention is shown not by the above-described embodiment (including modifications) but by the scope of claims for patent, and includes all modifications within the scope equivalent to the scope of claims and their configurations.
For example, in the above-described embodiment, the case where both the upper and lower communication networks are PON has been exemplified. However, the upper or lower network or both networks may be a CDN (Coaxial Distribution Network) using a coaxial cable (Coax) or the like. An HFC (Hybrid Fiber-Coaxial Network) may be used.

In general, the CDN includes a network in which a CLT (Coax Line Terminal) that is a master station device and a plurality of CNUs (Coax Network Units) that are slave station devices are connected one-to-many with a coaxial cable.
Also in the CDN system, access control similar to MPCP defined in IEEE Std 802.3 ^™ -2008 is used to perform CNU registration and uplink multiple access control. That is, although the CDN and the PON are different in transmission media, the logical operation in the system is the same, and therefore the present invention can be applied.

  As described above, the communication lines constituting the upper communication network and the lower communication network are not limited to optical fibers, and may be coaxial cables, other wired lines, or wireless. It may be a line.

When the communication method between the master station device 10 and the relay device 20 in the above-described embodiment is generalized, it can be said that these devices 10 and 20 are communication devices that employ uplink multiple access control for subordinate devices.
Here, uplink multiple access control is a TDMA (Time Division Multiple Access) communication method in which a medium (carrier frequency) used for transmission is divided in the time domain and accessed from a plurality of terminals, and is used in PON and CDN. MPCP, which belongs to the category of uplink multiple access control, also relates to uplink communication.

Therefore, the master station device 10 of the above-described embodiment is a communication device that performs uplink multiple access control for a plurality of relay devices 20 in the first communication network (“upper PON” in the multi-stage PON) that is the upper network. It can be said.
In addition, the relay device 20 of the above-described embodiment functions as a master station in the second communication network (“upper PON” in the multi-stage PON) as a lower network and performs uplink multiple access control for a plurality of relay devices. It can be said that it is a device.

10 Master station equipment (OLT)
20 relay device 21 slave station function unit 22 master station function unit 23 data distribution unit 24 device control unit 30 slave station device (ONU)
T1 Tag information for slave station equipment T2 Tag information for relay equipment

Claims (9)

There is a first communication network in which the master station device performs uplink multiple access control on the relay device, and a second communication network in which the relay device performs uplink multiple access control on the slave station device, and the first communication network A communication system in which the second communication network is connected via one or more relay devices,
The relay apparatus connected to the second communication network includes tag information for identifying the slave station apparatus that is the transmission source in an upstream data frame transferred from the second communication network to the first communication network. Grant,
The base station apparatus adds up the amount of uplink traffic for each slave station apparatus based on the tag information included in the data frame received from the first communication network.   The communication system according to claim 1, wherein the aggregation for each slave station device includes aggregation for each priority defined for the data frame.   The master station device identifies the slave station device that is a transmission source of the data frame based on a combination of the tag information included in the data frame and a logical link of the relay device in the first communication network. The communication system according to claim 1. The relay device also provides tag information for identifying the device itself to the data frame,
The communication system according to claim 1, wherein the master station device identifies the slave station device that is a transmission source of the data frame based on a combination of the two types of the tag information included in the data frame. A relay device capable of communicating in both the first communication network and the second communication network,
According to the uplink multiple access control performed by the master station device of the first communication network,
Performing uplink multiple access control for the slave station apparatus of the second communication network,
A relay device, wherein tag information for identifying the slave station device that is a transmission source is added to an upstream data frame transferred from the second communication network to the first communication network. A relay device that performs uplink multiple access control on a slave station device of the second communication network, and a master station device that communicates in the first communication network,
Perform uplink multiple access control for the relay device,
Based on tag information for identifying the slave station device that is the transmission source included in the uplink data frame received from the relay device, the amount of uplink traffic is aggregated for each slave station device. A master station device. A communication method in which a master station device of a first communication network performs uplink multiple access control on a relay device, and the relay device performs uplink multiple access control on a slave station device of a second communication network,
Attaching tag information for identifying the slave station device that is the transmission source to an upstream data frame transferred from the second communication network to the first communication network;
Summing up the amount of upstream traffic for each of the slave station devices based on the tag information contained in the data frame. The said relay apparatus has an upstream buffer for absorbing the difference between the transmission rate of the upstream signal transmitted to the first communication network and the transmission rate of the upstream signal received from the second communication network. 4. The communication system according to 4 . The relay apparatus has a downlink buffer for absorbing a difference between a transmission rate of a downlink signal received from the first communication network and a transmission rate of a downlink signal transmitted to the second communication network. 4. The communication system according to 4 .

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