JP7419986B2 - Communication equipment, home equipment, and optical communication systems - Google Patents

Description

The present invention relates to a communication device, a home device, and an optical communication system.

Patent Document 1 describes an OLT (Optical Line Terminal), a plurality of pluggable ONUs (Optical Network Units) that comply with the MSA (Multi Source Agreement) standard, which are connected by an OLT and a PON line, and a pluggable ONU that can be inserted. A PON (Passive Optical Network) system is described that includes a line concentrator having a plurality of physical ports.

Japanese Patent Application Publication No. 2010-252192

In the PON system of Patent Document 1, if some of the functions of the hardware components included in the pluggable ONU (for example, OAM) are transferred to the line concentrator, the circuit configuration of the hardware components can be reduced in size, and the pluggable ONU can be It can be made smaller and more versatile.
However, Patent Document 1 does not assume a control communication procedure for a line concentrator to appropriately act as an OAM link between OLT/ONU.

In view of the conventional problems, an object of the present disclosure is to enable a communication device to which a home device can be connected to appropriately act as a control communication link between a station device and a home device.

A device according to an aspect of the present disclosure is a communication device that communicates with a home device that configures a PON system together with a central office device, and has one or more physical ports to which the home device can be connected, and a connected The management control unit includes a management control unit that manages the home device, and a relay processing unit that relays communication frames transmitted and received by the home device and the management control unit, and the management control unit manages the home device and the following. On the condition that the first communication link is established, the following second communication link is established with the station-side device.
First communication link: A control communication link that the communication device attempts to establish with the home device as the management target Second communication link: A control communication link that the station device attempts to establish with the home device as the management target

A device according to another aspect of the present disclosure is a home device that configures a PON system together with a station device, and includes an optical transceiver, a PON processing unit connected to the optical transceiver, and a home device connected to the PON processing unit. The PON processing unit includes a PHY processing unit and a terminal module connected to the PHY processing unit and connectable directly or indirectly to a physical port of a communication device. and establishes the first communication link with the station-side device, and relays the control frame used for establishing the second communication link without establishing the second communication link with the station-side device.

A system according to an aspect of the present disclosure includes a station-side device, a plurality of home-side devices connected to the station-side device via a PON line, and a communication device to which all or part of the plurality of home-side devices are connected. A PON system comprising: the home-side device connected to the communication device does not establish the following second communication link with the station-side device, and is used for establishing the second communication link. Relaying the control frame, the communication device establishes the second communication link with the station device on the condition that the first communication link is established with the home device connected to the communication device. .

According to the present disclosure, a communication device to which a home device can be connected can appropriately act as a control communication link between a station device and a home device.

FIG. 1 is a schematic diagram showing an example of the overall configuration of an optical communication system. FIG. 2 is a block diagram showing an example of the internal configuration of the OLT, pluggable ONU, and line concentrator. FIG. 3A is a sequence diagram illustrating an example of a pluggable ONU monitoring process. FIG. 3B is a sequence diagram showing another example of the pluggable ONU monitoring process. FIG. 4 is a sequence diagram illustrating an example of a link-up procedure for PON communication. FIG. 5 is a block diagram showing the overall configuration of an optical communication system according to a first modification. FIG. 6 is a block diagram showing the overall configuration of an optical communication system according to a second modification.

<Summary of embodiments of the present invention>
Hereinafter, an overview of the embodiments of the present invention will be listed and explained. Note that at least some of the embodiments described below may be combined arbitrarily.

(1) The communication device of this embodiment is a communication device that communicates with a home device that configures a PON system together with a station device, and is connected to one or more physical ports to which the home device can be connected. a management control unit that manages the home-side device; and a relay processing unit that relays communication frames transmitted and received by the home-side device and the management control unit, and the management control unit manages the home-side device and the following: On the condition that the first communication link has been established, the following second communication link is established with the station-side device.
First communication link: A control communication link that the communication device attempts to establish with the home device as the management target Second communication link: A control communication link that the station device attempts to establish with the home device as the management target

According to the communication device of this embodiment, the management control unit establishes the second communication link with the station device on the condition that the first communication link with the home device is established, so the management control unit establishes the second communication link with the station device. A communication device to which the device can be connected can appropriately act as a control communication link (second communication link) between the station-side device and the home-side device.

(2) In the communication device of the present embodiment, it is preferable that the management control unit acquires setting information of the home-side device through control communication with the station-side device opened by establishing the second communication link. .
In this way, the management control unit of the communication device can appropriately acquire the setting information of the home device that the station device has transmitted for the home device.

(3) In the communication device of the present embodiment, the management control unit transmits the acquired setting information of the home device to the home device through control communication with the home device opened by establishing the first communication link. Preferably, the information is sent to the device.
In this way, the management control unit of the communication device can appropriately provide the setting information of the home device acquired from the station device to the home device.

(4) In the communication device of the present embodiment, the management control unit acquires address information of the connected home-side device through control communication when establishing the first communication link, and applies the acquired address information to the address information of the connected home-side device. It is preferable to determine the destination of the acquired setting information of the home device based on the above information.
In this way, when the setting information of a plurality of home devices is acquired from the station device, the communication device can provide the setting information of the home devices to an appropriate destination.

(5) The home device of this embodiment is a home device that configures a PON system together with the station device, and includes an optical transceiver, a PON processing unit connected to the optical transceiver, and a PON processing unit connected to the PON processing unit. and a terminal module connected to the PHY processing unit, which is connectable directly or indirectly to a physical port of a communication device, and the PON processing unit includes The first communication link is established with the communication device, the second communication link is not established with the station-side device, and the control frame used for establishing the second communication link is relayed.

According to the home device of this embodiment, the PON processing unit establishes the first communication link with the communication device, does not establish the second communication link with the station device, and does not establish the second communication link with the station device. Since the control frame used for establishment is relayed, the communication device to which the home device can be connected can appropriately act as a control communication link (second communication link) between the station device and the home device.

(6) The PON system of this embodiment is a system that is a combination comprising the communication devices (1) to (4) described above and the home-side device described in (5) above.
Therefore, the PON system of this embodiment has the same effects as the above-mentioned communication devices (1) to (4) and the above-mentioned home-side device (5).

<Details of embodiments of the present invention>
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that at least some of the embodiments described below may be combined arbitrarily.

[Overall configuration of optical communication system]
FIG. 1 is a schematic diagram showing an example of the overall configuration of an optical communication system.
As shown in FIG. 1, the optical communication system of this embodiment includes a PON system including a station-side device 1, a home-side device 2, a line concentrator 3, and the like.
The station-side device 1 is an optical line terminal (OLT) connected to the upper side of the PON line 4. The home device 2 is an optical line terminal unit (ONU) located on the lower side of the PON line 4. Hereinafter, the station-side device 1 will be referred to as "OLT1" and the home-side device 2 will be referred to as "ONU2."

The PON of this embodiment is, for example, a PON (eg, GE-PON or 10G-EPON) that complies with IEEE communication standards.
The PON of this embodiment may be a PON (eg, G-PON, XG-PON, XGS-PON, or NG-PON2) that complies with ITU-T communication standards.

The OLT 1 is installed, for example, in a communications carrier's office building. OLT1 is connected to the upper network. The ONU 2 and the line concentrator 3 are installed, for example, in a building of a communication service subscriber (user).
The ONU 2 includes a "pluggable type ONU 2A" which is relatively small in size and complies with the MSA (Multi-Source Agreement) standard, and a "stationary type ONU 2B" which is relatively large in size and does not conform to the MSA standard.

The MSA standard is, for example, "SFP" (Small Form-factor Pluggable), "SFP+" (Small Form-factor Pluggable Plus), or "XFP" (10 Gigabit Small Form-factor Pluggable).
In the following, the "pluggable ONU 2A" may be abbreviated as "ONU2A", and the "stationary ONU 2B" may be abbreviated as "ONU2B". Items common between ONU2A and ONU2B will be described as "ONU2" using the common code "2".

The line concentrator 3 includes, for example, a management switch including a plurality of physical ports. The physical ports of the line concentrator 3 include a slot-in type physical port Pi (i=1, 2...m) to which a pluggable ONU 2A can be connected, and a physical port Qj (j) to which a communication cable such as a LAN cable can be connected. =1, 2...n) is included.
The line concentrator 3 has an Ethernet ("Ethernet" is a registered trademark) communication function that complies with 10/100/1000BASE-T, etc., an L2/L3 layer network function, a QoS (Quality of Service) function, and a VLAN ( Virtual LAN) functions, etc.

One or more pluggable ONUs 2A and one or more user terminals 5 are connected to the line concentrator 3. One or more user terminals 5 are connected to the stationary ONU 2A. The user terminal 5 is an example of a "lower-order device" that is a communication device on the subscriber side.
The user terminal 5 is comprised of a computer device such as a personal computer that is capable of Ethernet communication. The user terminal 5 may be connected to the line concentrator 3 or the ONU 2B via a relay network (not shown).

The PON line 4 is composed of a tree-structured optical line in which optical fibers are branched by an optical splitter 6. The OLT 1 is connected to the main fiber 7 of the PON line 4, and the ONU 2 is connected to the branch fiber 8 of the PON line 4.
The optical splitter 6 passively splits or multiplexes an input optical signal without requiring power supply.

The downlink optical signal sent out by the OLT 1 is split at the optical splitter 6 and transmitted to each ONU 2 through the branch fiber 8 . Upstream optical signals sent out by each ONU 2 are converged at an optical splitter 6 and transmitted to the OLT 1 through a trunk fiber 7.
Since the upstream optical signals sent out by the ONUs 2 are combined at the optical splitter 6, multiplexing is required to prevent upstream optical signals of the same wavelength from colliding after merging. For this reason, time division multiplexing based on MPCP (Multi-Point Control Protocol) is performed in PON.

Specifically, the ONU 2 transmits a control frame (report) in which the length of data in its own buffer (transmission request amount) is written to the OLT 1.
The OLT 1 calculates the upstream transmission start time and transmission time length to be instructed to each ONU 2 based on the reports collected from the ONUs 2 under its control. The OLT 1 transmits a control frame (gate) containing the calculation result to each ONU 2.

Each ONU 2 transmits data corresponding to the transmission time length designated by the gate to the OLT 1 at the transmission start time designated by the gate. At the same time, the ONU 2 transmits the next transmission request amount together with a report to the OLT 1.
Further, the OLT 1 executes P2MP (Point To Multi Point) discovery, and when detecting the connection of the ONU 2 to the PON line 4, executes a registration process for the detected ONU 2. At this time, an LLID (Logical Link ID) is assigned to the ONU 2.

Since the PON system complies with Ethernet, the OLT 1 has an OAM (Operations, Administration and Maintenance) function that complies with the Ethernet standard.
For this reason, the OLT 1 uses, for example, normal OAM frames specified in Clause 57 of IEEE 802.3-2008, and extended OAM frames that can be independently defined by communication carriers for the purpose of maintenance management, in the communication equipment to be managed. Transmits and receives data to and from a certain ONU2.

In the optical communication system of FIG. 1, the stationary ONU 2B may not be connected to the PON line 4, and only the pluggable ONU 2A may be accommodated in the OLT 1.
Further, the system configuration may include a plurality of line concentrators 3, and the number of pluggable ONUs 2A connected to one line concentrator 3 may be at least one or more.

[Internal configuration of OLT]
FIG. 2 is a block diagram showing an example of the internal configuration of the OLT 1, the pluggable ONU 2A, and the line concentrator 3.
As shown in FIG. 2, the OLT 1 includes an optical transceiver (TRx) 11, a PON processing section 12, a switch section 13, and a management control section 14. The management control unit 14 includes a CPU (Central Processing Unit), a memory, and the like.

The optical transceiver 11 is an optical device including a subassembly (eg, Bidirectional Optical Sub-Assembly) that mutually converts optical signals and electrical signals. The optical transceiver 11 is optically connected to the PON line 4 and electrically connected to the PON processing section 12 .
The optical transceiver 11 converts an uplink optical signal inputted from the PON line 4 into an electrical signal and inputs it to the PON processing unit 12, converts the electrical signal inputted from the PON processing unit 12 into a downlink optical signal, and converts the electrical signal inputted from the PON processing unit 12 into a downlink optical signal. Send to 4.

The PON processing unit 12 is composed of an integrated circuit (for example, a MAC chip for OLT) that executes predetermined communication processing based on the PON communication standard.
If the upstream frame input from the optical transceiver 11 is a report, the PON processing unit 12 calculates the upstream transmission start time and transmission time length of the ONU 2 . The PON processing unit 12 generates a gate addressed to a predetermined LLID (ONU 2) including the calculation result, and outputs the generated gate to the optical transceiver 11.

The PON processing unit 12 also executes P2MP discovery and registration processing of the ONU 2, and transmission and reception of OAM frames that manage the ONU 2.
If the uplink frame input from the optical transceiver 11 is a user frame, the PON processing unit 12 outputs the user frame to the switch unit 13 .
If the downlink frame input from the switch unit 13 is a user frame, the PON processing unit 12 outputs the user frame to the optical transceiver 11.

The switch unit 13 is composed of an integrated circuit such as an FPGA (Field Programmable Gate Array), which determines an output port according to the destination of an L2 layer frame input thereto.
When the downlink frame input from the upper network is a user frame, the switch unit 13 outputs the downlink frame to the PON processing unit 12.
If the upstream frame input from the PON processing unit 12 is a user frame, the switch unit 13 sends the user frame to the upper network.

The management control section 14 is connected to the switch section 13 and the PON processing section 12. The management control unit 14 is also communicably connected to a management terminal 15 of a communication carrier. The management terminal 15 may communicate with the management control unit 14 through an upper network.
The management control unit 14 can set QoS (Quality of Service) parameters (for example, maximum communication band) of the switch unit 13. The switch unit 13 adjusts the amount of data communication of the user frame so that the set parameter value is achieved.

The management terminal 15 can transmit setting information of the OLT 1 and ONU 2 to the management control unit 14. Upon receiving the configuration information of the OLT 1, the management control unit 14 adjusts the parameters of each unit of the own device according to the received configuration information.
Upon receiving the configuration information of the ONU 2, the management control unit 14 outputs the received configuration information to the PON processing unit 12. The PON processing unit 12 generates a control frame (for example, an extended OAM frame) containing configuration information of the ONU 2 and outputs it to the optical transceiver 11.

The setting information of the ONU 2 includes, for example, at least one of the following information 1 to 4.
Information 1: Setting parameters of the MAC chip of the ONU 2 Information 2: Authentication information (password, etc.) for the user terminal 5 that communicates with the ONU 2
Information 3: Encryption key used between OLT/ONU Information 4: Setting information for queue buffer size included in ONU 2

[Internal configuration of pluggable ONU]
As shown in FIG. 2, the pluggable ONU 2A includes an optical transceiver (TRx) 21, a PON processing section 22, a PHY (physical layer) processing section 23, and a terminal module (terminal section) 24. The terminal module 24 is comprised of a connector having a predetermined structure and number of terminals that conform to a predetermined MSA standard.

The optical transceiver 21 is an optical device including a subassembly (eg, Bidirectional Optical Sub-Assembly) that mutually converts optical signals and electrical signals. The optical transceiver 21 is optically connected to the PON line 4 and electrically connected to the PON processing section 22 .
The optical transceiver 21 converts the downlink optical signal inputted from the PON line 4 into an electrical signal and inputs it to the PON processing unit 22, converts the electrical signal inputted from the PON processing unit 22 into an upstream optical signal, and converts the electrical signal inputted from the PON processing unit 22 into an uplink optical signal to connect the PON line. Send to 4.

The PON processing unit 22 is composed of an integrated circuit (for example, a MAC chip for ONU) that executes predetermined communication processing based on the PON communication standard.
The PON processing unit 22 generates a report that describes the data length in its own buffer, and outputs it to the optical transceiver 21. If the downlink frame input from the optical transceiver 21 is a gate, the PON processing unit 22 generates a user frame including the data currently being accumulated in the buffer and outputs it to the optical transceiver 21 according to the instructions written on the gate. do.

If the downlink frame input from the optical transceiver 21 is a user frame, the PON processing unit 22 outputs the user frame to the PHY processing unit 23 .
When the upstream frame input from the PHY processing unit 23 is a user frame, the PON processing unit 22 temporarily stores data included in the user frame in a buffer.

The PHY processing unit 23 is composed of an integrated circuit (for example, a PHY chip) that performs signal conversion and communication processing in the physical layer.
The PHY processing unit 23 converts the electrical signal input from the line concentrator 3 into a layer 2 electrical signal, and outputs the converted electrical signal to the PON processing unit 22. The PHY processing unit 23 converts the downlink frame input from the PON processing unit 22 into a layer 1 electrical signal, and sends the converted electrical signal to the line concentrator 3.

[Internal configuration of concentrator]
As shown in FIG. 2, the line concentrator 3 includes a plurality of upper-side transmitting/receiving sections 31, a switch section 32, a plurality of lower-side transmitting/receiving sections 33, and a management control section 34. The management control unit 34 is composed of a CPU, memory, and the like.
The upper-side transmitter/receiver 31 is connected to physical ports P1, P2, and the lower-side transmitter/receiver 33 is connected to physical ports Q1, Q2. In FIG. 2, a case is illustrated in which there are two transmitting/receiving sections 31 and 33, but there may be three or more.

The upper-side transmitter/receiver 31 is composed of an integrated circuit (for example, a PHY chip) that performs signal conversion and communication processing in the physical layer.
The upper-side transmitting/receiving section 31 converts the electrical signal input from the ONU 2A into a layer 2 electrical signal, and outputs the converted electrical signal to the switch section 32. The upper-side transmitting/receiving unit 31 converts the electrical signal input from the switch unit 32 into a layer 1 electrical signal, and sends the converted electrical signal to the ONU 2A.

The lower-side transmitter/receiver 33 is composed of an integrated circuit (for example, a PHY chip) that performs signal conversion and communication processing in the Ethernet physical layer conforming to 10/100/1000BASE-T or the like.
The lower-side transmitting/receiving section 33 converts the electrical signal input from the user terminal 5 into a layer 2 electrical signal, and outputs the converted electrical signal to the switch section 32 . The lower-side transmitting/receiving unit 33 converts the electrical signal input from the switch unit 32 into a layer 1 electrical signal, and sends the converted electrical signal to the user terminal 5.

The switch unit 32 is composed of an integrated circuit such as an FPGA that determines an output port according to the destination of an L2 layer frame input thereto.
In the switch unit 32, the correspondence relationship between the upper-side transmitting/receiving unit 31 and the lower-side transmitting/receiving unit 33 is set in advance by VLAN setting by the management control unit 34 or the like. A VLAN (hereinafter referred to as “management VLAN”) for management communication between the management control unit 34 and the ONU 2A is also preset in the switch unit 32. In the management VLAN, frame loopback between different physical ports Pi is prohibited.

The switch unit 32 performs relay processing of the input frame (Ethernet frame with a VLAN tag) according to the correspondence relationship set by the management control unit 34.
Therefore, the upper-side transmitting/receiving unit 31, the switch unit 32, and the lower-side transmitting/receiving unit 33 function as a relay processing unit that relays communication frames transmitted and received by the connected ONU 2A, the connected user terminal 5, and the management control unit 34. do.

The management control section 34 is connected to the switch section 32. The management control unit 34 can also communicate with the management terminal 15 of the communication carrier connected to the OLT 1.
Communication between the management terminal 15 and the management control unit 34 of the line concentrator 3 is performed via the OLT 1, the PON line 4, and the ONU 2A. Note that the management terminal 15 may be directly connected to the management control unit 34 of the line concentrator 3.

[Virtualization of ONU functions]
In this embodiment, some of the functions of the hardware components (specifically, the PON processing unit 22) included in the ONU 2A are transferred to the line concentrator 3. That is, the management control unit (CPU) 34 of the line concentrator 3 executes some of the functions of the PON processing unit 22.
The more functions that are transferred to the line concentrator 3, the smaller the circuit configuration of the hardware components of the ONU 2A can be, and the more compact and versatile the ONU 2A can be.

In FIG. 2, a case is illustrated in which the function of the ONU 2A transferred to the management control unit 34 of the line concentrator 3 is OAM between OLT/ONU. Therefore, other functions for PON communication such as MPCP remain as functions of the PON processing unit 22 of the ONU 2A.
In order for the management control unit 34 to perform OAM between the OLT and ONU on behalf of the management control unit 34, the management control unit 34 needs to transmit and receive OAM frames for which the OLT 1 manages the ONU 2A.

Therefore, the PON processing unit 22 of the ONU 2A performs “first processing” on the downlink OAM frame input from the optical transceiver 21 and outputs the processed frame to the PHY processing unit 23, so that the downlink transmitted by the OLT 1 The OAM frame is relayed to the line concentrator 3.
The first process includes a process of adding a management VLAN tag to a downstream OAM frame, and a process of replacing the source address of the downstream OAM frame with the MAC address of the device itself.

In addition, if the destination of the upstream OAM frame input from the PHY processing unit 23 is the own device, the PON processing unit 22 of the ONU 2A performs “second processing” on the upstream OAM frame and outputs the processed frame. By outputting to the optical transceiver 21, the upstream OAM frame transmitted by the line concentrator 3 is relayed to the OLT 1.
The second process involves deleting the VLAN tag from the upstream OAM frame and rewriting the destination address to the specified address of the OAM protocol (multicast address for slow protocol), and changing the source address of the upstream OAM frame to the own device. This includes a process of replacing the address with a MAC address.

In order for the management control unit 34 to perform OAM between the OLT and ONU on behalf of the management control unit 34, it is necessary for the OLT 1 to determine which ONU 2A is the OAM frame transmitted as the management target. For this reason, the management control unit 34 collects in advance address information (for example, MAC address) of the ONU 2A that is connected to the line concentrator 3 and is operable.
Specifically, the management control unit 34 of the line concentrator 3 takes the installation of the pluggable ONU 2A into its own device as an opportunity to independently establish an OAM link that targets the ONU 2A, and, on the condition that this link is established, / Acts as an OAM link between ONUs.

That is, when two types of OAM links (control communication links) are defined as follows, the management control unit 34 establishes the second OAM link with the OLT 1 on the condition that the first OAM link with the ONU 2A is established.
1st OAM link: OAM link that the own device attempts to establish with ONU 2A as the management target 2nd OAM link: OAM link that OLT 1 attempts to establish with ONU 2A as the management target

The management control unit 34 collects the address information of the ONU 2A through control communication when establishing the first OAM link, and records the management table 35 including the collected address information in the memory.
As shown in FIG. 2, the management table 35 consists of tabular data including, for example, columns of "entry", "port number", and "MAC address". The "port number" indicates the number values of the physical ports P1 and P2 to which the ONU 2A is attached, and the "MAC address" indicates the MAC address value notified from the ONU 2A.

Next, the management control unit 34 refers to the recorded management table 35 and establishes a second OAM link instead of the ONU 2A.
Specifically, the management control unit 34 executes OAM discovery with the OLT 1 and establishes a second OAM link with the OLT 1. Further, if the extended OAM frame after the establishment of the second OAM link includes configuration information of the ONU 2A, the management control unit 34 transmits the acquired configuration information to the ONU 2A through control communication after the establishment of the first OAM link. .

[First OAM link procedure]
FIG. 3A is a sequence diagram showing an example of the first OAM link executed by the management control unit 34. This monitoring process is executed for each physical port Pi. Furthermore, the following message communication is performed in a predefined management VLAN.

As shown in FIG. 3A, the PON processing unit 22 of the ONU 2A sends a connection request message to the management control unit 34 of the line concentrator 3 upon attachment to the slot-in type physical port Pi included in the line concentrator 3. (Step S11). The MAC address of the source of the connection request message is the address of the ONU 2A itself.

When the management control unit 34 of the line concentrator 3 receives the connection request message, it transmits a response message notifying the connection request message to the PON processing unit 22 of the ONU 2A (step S12).
In this case, the management control unit 34 records the MAC address value and port number value of the ONU 2A in the management table 35. Thereafter, the PON processing unit 22 and the management control unit 34 become able to transmit and receive arbitrary information to and from the ONU 2A (step S13). That is, by establishing the first OAM link, control communication between the PON processing section 22 and the management control section 34 is established.

FIG. 3B is a sequence diagram showing another example of the first OAM link executed by the management control unit 34. This monitoring process is also executed for each physical port Pi.
As shown in FIG. 3B, the management control unit 34 of the line concentrator 3 broadcasts a MAC address request message to the slot-in physical port Pi at predetermined intervals (for example, 1 second) (step S21).

When the ONU 2A is attached to a predetermined physical port Qi of the line concentrator 3, the PON processing unit 22 of the ONU 2A transmits a response message including the MAC address of the ONU 2A to the management control unit 34 of the line concentrator 3 (step S22 ).
When the management control unit 34 of the line concentrator 3 successfully receives the MAC address, it transmits a response message notifying the same to the PON processing unit 22 of the ONU 2A (step S23).

In this case, the management control unit 34 records the received MAC address value and port number value in the management table 35. Thereafter, the PON processing section 22 and the management control section 34 are in a state where they can send and receive arbitrary information to and from the ONU 2A (step S24). That is, by establishing the first OAM link, control communication between the PON processing section 22 and the management control section 34 is established.

[Link up procedure for PON communication]
FIG. 4 is a sequence diagram illustrating an example of a link-up procedure for PON communication.
As shown in FIG. 4, the OLT 1 performs OAM discovery after completing the P2MP link up and attempts to establish a second OAM link in the PON communication interval.
In this case, in this embodiment, the PON processing unit 22 of the ONU 2A executes P2MP discovery, but the management control unit 34 of the line concentrator 3 performs OAM discovery.

Specifically, upon establishing an MPCP link with the ONU 2A of a predetermined LLID, the PON processing unit 12 of the OLT 1 transmits an Information OAM frame containing predetermined information about the OLT 1 (step S31).
If the ONU 2 is a normal ONU 2B, the ONU 2B responds to the Information OAM frame, but the PON processing unit 22 of the pluggable ONU 2A relays the Information OAM frame received from the OLT 1 to the line concentrator 3 (step S32).

In relaying the downstream OAM frame in step 32, the PON processing unit 22 of the pluggable ONU 2A adds a management VLAN tag to the OAM frame and replaces the source address with its own MAC address (first process).

The management control unit 34 of the line concentrator 3 that has received the Information OAM frame sends up the Information OAM frame in which predetermined information of the ONU 2A is written (step S33).
In transmitting the upstream OAM frame in step 33, the management control unit 34 of the line concentrator 2 adds a management VLAN tag to the Information OAM frame and specifies the MAC address of the ONU 2A as the destination address.

The PON processing unit 22 of the pluggable ONU 2A relays the Information OAM frame received from the line concentrator 3 to the OLT 1 (step S34).
In the relay of the upstream OAM frame in step 34, the PON processing unit 22 of the pluggable ONU 2A deletes the management VLAN tag from the OAM frame, replaces the destination address with a specified address (multicast address for slow protocol), and sends Replace the original address with its own MAC address (second process).

If the OAM discovery using the Information OAM frame is successful, an OAM link (second OAM link) with the OLT 1 is established, and from then on, it becomes possible to send and receive any OAM frame (SEND_ANY state).
That is, by establishing the second OAM link, control communication between the OLT 1 and the management control unit 34 is established. Note that the same conversion processing (first and second processing) as in steps S32 and S34 described above is performed also in relaying OAM frames used for control communication after opening.

When the OAM link is established, the PON processing unit 12 of the OLT 1 transmits, for example, an extended OAM frame including configuration information of the ONU 2A (step S35).
If the ONU 2 is a normal ONU 2B, the ONU 2B responds to the extended OAM frame, but the PON processing unit 22 of the pluggable ONU 2A relays the extended OAM frame received from the OLT 1 to the line concentrator 3 (step S36).

The management control unit 34 of the line concentrator 3 that has received the extended OAM frame generates a control frame including the setting information of the ONU 2A, and transmits the generated control frame to the ONU 2A (step S37).
In this case, the management control unit 34 of the line concentrator 3 refers to the management table 35 and determines the destination of the control frame. Therefore, when setting information of a plurality of ONUs 2A is acquired from the OLT 1, the setting information can be provided to an appropriate destination.

The PON processing unit 12 of the ONU 2A that received the control frame transmits a response frame to the line concentrator 3 (step S38).
Note that the transmission and reception of the control frame and the response frame in steps S37 and S38 are performed by the control communication opened by establishing the first OAM link.

The management control unit 34 of the line concentrator 3 that has received the response frame transmits an extended OAM frame for response upstream (step S39). Note that the transmission and reception of extended OAM frames in steps 35 and 39 are performed by control communication opened by establishing the second OAM link.
The PON processing unit 22 of the ONU 2A relays the extended OAM frame received from the line concentrator 3 to the OLT 1 (step S40).

[First modification]
FIG. 5 is an overall configuration diagram showing a first modified example of the optical communication system.
As shown in FIG. 5, in the optical communication system according to the first modification, a radio base station used for mobile communication is connected to a higher-level device 40, which is a signal processing unit located on the upper-level side, and a higher-level device 40 located on the lower-level side. It is separated into a lower device 50 which is an antenna section, and a mobile fronthaul (MFH) which is an optical communication section is interposed between the upper device 40 and the lower device 50.

The upper level device 40 of the radio base station is composed of, for example, a BBU (Base Band Unit). The lower-order device 50 of the wireless base station is composed of, for example, an RRH (Remote Radio Head). The lower device 50 is similar to the user terminal 5 described above in that it is a communication node closer to the subscriber than the ONU 2A.
Hereinafter, a higher-level device of a wireless base station will be referred to as a "BBU", and a lower-level device of a wireless base station will be referred to as an "RRH". The RRH 50 is capable of wireless communication with one or more mobile terminals 60 included in its own communication cell (for example, a small cell).

The BBU 40 and the OLT 1 are communicably connected by a predetermined communication cable (for example, an optical fiber).
The ONU 2 is a pluggable ONU 2A, and is connected to a slot-in type physical port of the line concentrator 3. The RRH 50 is connected to the line concentrator 3 via a predetermined communication cable (for example, a LAN cable).

In the modified example of FIG. 5, among a plurality of ONUs 2A accommodated in the same OLT 1 and connected to the same line concentrator 3, some ONUs 2A are set to the active system, and the remaining ONUs 2A are set to the backup system. ONU2A is made redundant.
In this way, if the active ONU 2A fails, the route setting of the line concentrator 3 can be switched so that the backup ONU 2A is connected to the RRH 50. communication) can be protected.

[Second modification example]
FIG. 6 is an overall configuration diagram showing a second modified example of the optical communication system.
As shown in FIG. 6, the optical communication system according to the second modification includes a plurality of OLTs 1 connected to an upper network, a plurality of ONUs 2 connected to the OLT 1 by a PON line 4, and a concentrator to which the plurality of ONUs 2 are connected. It includes a device 3 and a user terminal 5 connected to the line concentrator 3.

The ONU 2 is a pluggable ONU 2A, and is connected to a slot-in type physical port of the line concentrator 3. The user terminal 5 is connected to the line concentrator 3 via a predetermined communication cable (for example, a LAN cable).

In the modified example shown in FIG. 6, among a plurality of ONUs 2A accommodated in separate OLTs 1 and connected to the same line concentrator 3, some ONUs 2A are set to the active system, and the remaining ONUs 2A are set to the backup system. , the PON line 4 is made redundant.
In this way, if the OLT 1 or ONU 2A of the active PON line 4 fails, the route settings of the line concentrator 3 can be switched so that the ONU 2A of the backup PON line 4 is connected to the user terminal 5. , protection of user communications by the user terminal 5 can be achieved.

[Other variations]
The embodiments described above are illustrative in all respects and are not restrictive. The scope of rights of the present invention includes all changes within the scope of equivalents to the configurations described in the claims.
For example, in the above-described embodiment, the ONU 2A does not necessarily have to be a pluggable type, and may be a type of ONU 2 that is indirectly connected to a physical port of a communication device such as the line concentrator 3 via a communication cable.

In the above-described embodiment, the communication device to which the ONU 2A can be connected is the line concentrator 3, but the communication device has at least one physical port Pi for the ONU 2A, such as a home gateway (HGW) or a general-purpose server. It may also be a communication device that has.
In the above embodiment, if the communication device to which the ONU 2A can be connected is a communication device such as a general-purpose server to which the user terminal 5 is not connected, the physical port Qj for the user terminal (lower device) 5 is not required.

<Additional notes on features of embodiments>
The embodiment described above includes the features described below.

[Appendix 1]
A home-side device that constitutes a PON system together with a station-side device,
optical transceiver,
a PON processing unit connected to the optical transceiver;
a PHY processing unit connected to the PON processing unit;
A terminal module connected to the PHY processing unit, the terminal module being connectable directly or indirectly to a physical port of a communication device,
The PON processing unit includes:
Establishing the following first OAM link with the communication device in which the management VLAN is set,
Performing a first process on a downstream OAM frame inputted from the optical transceiver, outputting the processed frame to the PHY processing unit, and performing a second process on an upstream OAM frame inputted from the PHY processing unit. A home-side device that causes the communication device to establish a second OAM link as described below by outputting the processed frame to the optical transceiver.
First OAM link: OAM link that the communication device attempts to establish with the home device as the management target Second OAM link: OAM link that the station device attempts to establish with the home device as the management target

[Appendix 2]
The first process includes:
a process of adding a management VLAN tag to the downlink OAM frame;
The home device according to appendix 1, further comprising: replacing the source address of the downlink OAM frame with a MAC address of the home device.

[Appendix 3]
The second process includes:
Deleting a management VLAN tag from the upstream OAM frame and replacing the destination address with a specified address of the OAM protocol;
The home device according to Supplementary Note 1 or 2, further comprising: replacing the source address of the upstream OAM frame with the MAC address of the device itself.

1 OLT (station side device)
2 ONU (home device)
2A pluggable ONU (home device)
2B Stationary ONU (home device)
3 Line concentrator (communication device)
4 PON line 5 User terminal (lower device)
6 Optical splitter 7 Trunk fiber 8 Branch fiber 11 Optical transceiver (TRx)
12 PON processing unit 13 switch unit 14 management control unit 15 management terminal 21 optical transceiver (TRx)
22 PON processing section 23 PHY processing section 24 terminal module 31 Upper side transmission/reception section 32 Switch section 33 Lower side transmission/reception section 34 Management control section 35 Management table 40 BBU (upper unit)
50 RRH (lower device)
60 Mobile terminal P1, P2... Physical port Q1, Q2... Physical port

Claims (7)

A communication device that communicates with a home device that constitutes an optical communication system together with a station device,
one or more physical ports to which the home device can be connected;
a management control unit that manages the connected home device;
a relay processing unit that relays communication frames transmitted and received by the home-side device and the management control unit,
The management control unit includes:
A communication device that establishes the following second communication link with the station-side device on the condition that the following first communication link is established with the home-side device.
First communication link: A control communication link that the communication device attempts to establish with the home device as the management target Second communication link: A control communication link that the station device attempts to establish with the home device as the management target The management control unit includes:
The communication device according to claim 1, wherein the communication device acquires setting information of the home device through control communication with the station device opened by establishing the second communication link. The management control unit includes:
The communication device according to claim 2, wherein the acquired setting information of the home device is transmitted to the home device through control communication with the home device opened by establishing the first communication link. The management control unit includes:
Acquire address information of the connected home device through control communication when establishing the first communication link, and determine a destination of the acquired configuration information of the home device based on the acquired address information. The communication device according to claim 3. The optical communication system includes:
The communication device according to any one of claims 1 to 4, which is a PON system. A home-side device that constitutes an optical communication system together with a station-side device,
optical transceiver,
a MAC chip connected to the optical transceiver;
a PHY processing unit connected to the MAC chip;
A terminal module connected to the PHY processing unit, the terminal module being connectable directly or indirectly to a physical port of a communication device,
The MAC chip is
establishing the following first communication link with the communication device;
A home side that does not establish a second communication link described below with the station side device, but relays a control frame transmitted and received between the optical transceiver and the PHY processing unit, which is used to establish the second communication link. Device.
First communication link: A control communication link that the communication device attempts to establish with the home device as the management target Second communication link: A control communication link that the station device attempts to establish with the home device as the management target An optical communication system comprising a station-side device, a plurality of home-side devices connected to the station-side device by a tree-structured optical line, and a communication device to which all or a part of the plurality of home-side devices are connected. And,
The home device connected to the communication device is
Relaying a control frame transmitted and received between the station-side device and the communication device, which is used to establish the second communication link without establishing a second communication link with the station-side device, as described below,
The communication device includes:
An optical communication system that establishes the following second communication link with the station-side device on the condition that the following first communication link is established with the home-side device connected to the optical communication system.
First communication link: A control communication link that the communication device attempts to establish with the home device as the management target Second communication link: A control communication link that the station device attempts to establish with the home device as the management target

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