JP7056082B2 - Communication system, master station device, slave station device, and communication method - Google Patents

Description

The present invention relates to a communication system, a master station device, a slave station device, and a communication method .

Non-Patent Document 1 describes an OAM PDU (Operations, Administration and Maintenance Protocol Data Unit) for monitoring connectivity between a pair of communication devices as a type of Ethernet frame (“Ethernet” is a registered trademark). : Hereinafter referred to as "OAM frame") and LACP PDU (Link Aggregation Control Protocol's Protocol Data Unit: hereinafter referred to as "LACP frame") for treating a plurality of physical links as one logical link. The format of the slow protocol frame (hereinafter referred to as "SP frame") is specified.

According to the format described in Non-Patent Document 1, the SP frame must satisfy the following identification conditions 1 and 2 as common and fixed header information.
Identification condition 1: The value of Destination Address is "01-80-C2-00-00-02".
Identification condition 2: The value of the Length / Type field is "88-09".

Further, in the case of an OAM frame, the following identification condition 3A must be further satisfied, and in the case of a LACP frame, the following identification condition 3B must be further satisfied.
Identification condition 3A: The value of the Subtype field is "0x03".
Identification condition 3B: The value of the Subtype field is "0x01".

IEEE802.3ah Section 57.4.2, and Annex 57A

In a communication system including a pair of communication devices that exchange SP frames, another communication device in the system may receive another SP frame exchanged between communication nodes outside the system.
In this case, in order to reduce the processing load of the communication device, only the internal SP frames exchanged in the system are processed by the control unit, and the external SP frames received from outside the system are passed through without passing through the control unit. Is preferable.

However, according to the format described in Non-Patent Document 1, all communication frames satisfying the identification conditions 1 and 2 are determined to be SP frames regardless of whether they are internal SP frames or external SP frames, and in particular, identification condition 1 All communication frames satisfying ~ 3A or ~ 3B are determined to be OAM frames or LACP frames.
That is, in a communication device according only to the provisions of Non-Patent Document 1, it is not possible to distinguish whether the received SP frame is an internal SP frame or an external SP frame.

Therefore, the communication device in the system needs to have the control unit perform information processing in the data area even for an external SP frame unrelated to its own device, and the load of information processing related to SP (slow protocol) cannot be reduced so much. There's a problem.
In view of the conventional problems, it is an object of the present invention to reduce the load of information processing related to SP (slow protocol).

(1) The system according to one aspect of the present invention is a communication system including first and second communication devices that receive an external SP frame defined below from outside the system and exchange an internal SP frame defined below. The first communication device transfers the internal SP frame among the SP frames received from the system to the first control unit of the own device that performs information processing on the SP, and the external SP frame is the first control. It is sent out of the system without being transferred to the unit, and the second communication device transfers the internal SP frame among the SP frames received from the system to the second control unit of the own device that performs information processing on the SP. , The external SP frame is sent out of the system without being transferred to the second control unit.

Internal SP frame: SP frame exchanged between communication nodes in the system External SP frame: SP frame exchanged between communication nodes outside the system

(11) The communication device according to one aspect of the present invention belongs to the communication system that transmits the external SP frame defined above, and is a communication device that exchanges the internal SP frame defined above with another communication device. Of the control unit that processes information related to the SP and the SP frame received from within the system, the internal SP frame is transferred to the control unit, and the external SP frame is transmitted to the outside of the system without being transferred to the control unit. It is equipped with a reception processing unit.

(12) The method according to one aspect of the present invention belongs to a communication system that transmits an external SP frame defined above, and is executed in a communication device that exchanges the internal SP frame defined above with another communication device. Among the SP frames received from within the system, which is a frame transfer method, among the steps of transferring the internal SP frame to the control unit of the own device that performs information processing related to the SP, and among the SP frames received from within the system. A step of sending the external SP frame out of the system without transferring it to the control unit is included.

The present invention can be realized not only as a system and an apparatus having the above-mentioned characteristic configuration, but also as a program for causing a computer to execute such a characteristic configuration.
Further, the present invention can be realized as a semiconductor integrated circuit that realizes a part or all of a system and an apparatus.

According to the present invention, the load of information processing related to SP (slow protocol) can be reduced.

It is a system block diagram which shows the structural example of the communication system which concerns on 1st Embodiment. It is a block diagram which shows an example of the internal structure of a master station apparatus. It is a block diagram which shows an example of the internal structure of a slave station apparatus. It is explanatory drawing which shows an example of the determination method of the internal OAM frame. It is a flowchart which shows an example of the communication control executed by a master station apparatus. It is a flowchart which shows an example of the communication control executed by a slave station apparatus. It is a sequence diagram which shows an example of the transmission / reception procedure of an OAM frame. It is a system block diagram which shows the structural example of the communication system which concerns on 2nd Embodiment. It is a block diagram which shows an example of the internal structure of a communication device. It is explanatory drawing which shows an example of the determination method of the internal OAM frame. It is a sequence diagram which shows an example of the transmission / reception procedure of an OAM frame.

<Outline of Embodiment of the present invention>
Hereinafter, the outlines of the embodiments of the present invention will be described in a list.

(1) The communication system of the present embodiment is a communication system including first and second communication devices that receive the external SP frame defined below from outside the system and exchange the internal SP frame defined below. Among the SP frames received from the system, the first communication device transfers the internal SP frame to the first control unit of the own device that performs information processing on the SP, and transfers the external SP frame to the first control unit. It is sent out of the system without being transferred, and the second communication device transfers the internal SP frame among the SP frames received from the system to the second control unit of its own device that performs information processing on the SP, and the above-mentioned The external SP frame is sent out of the system without being transferred to the second control unit.

Internal SP frame: SP frame exchanged between communication nodes in the system External SP frame: SP frame exchanged between communication nodes outside the system

According to the communication system of the present embodiment, the first and second communication devices transfer the internal SP frame among the SP frames received from the system to their own control unit (first or second control unit). External SP frames are sent out of the system without being transferred to their own control unit.
Therefore, the first and second control units do not execute information processing for the external SP frame unrelated to the own device, and the load of information processing related to the SP can be reduced.

(2) In the communication system of the present embodiment, the first and second communication devices determine whether or not the received SP frame is the internal SP frame based on the identification information included in the received SP frame. do it.

(3) For example, as the identification information, the address value of one of the first and second communication devices may be adopted.
In this case, the first communication device is a master station device that provides an address value of its own device, and the second communication device is a slave station device that is provided with an address value from the master station device.

(4) In the communication system of the present embodiment, the master station device uses the SP frame generated by the first control unit of the own device, in which both the destination and the source are the address values of the own device, as the slave station device. It is preferable to send to.
By doing so, the slave station device can determine that the SP frame whose source address value is the address value of the master station device is the internal SP frame.

(5) In the communication system of the present embodiment, in the slave station device, the destination is the address value of the master station device and the source is the address value of the own device generated by the second control unit of the own device. It is preferable to transmit the SP frame to the master station device.
By doing so, the master station apparatus can determine that the SP frame whose destination address value is the address value of the master station apparatus is the internal SP frame.

(6) In the communication system of the present embodiment, it is preferable that the slave station device discards the SP frame whose destination address value is the address value of the master station device among the SP frames received from outside the system.
In this way, even if the spoofing communication node transmits an SP frame addressed to the master station device, the SP frame can be discarded by the slave station device.

(7) In the communication system of the present embodiment, the slave station device stores the address value of the master station device included in the SP frame first received from the master station device after linking up with the master station device. It is preferable that the storage unit further has a storage unit to be used, and the storage unit erases the address value of the master station apparatus according to the link down with the master station apparatus.
By doing so, the slave station device can send and receive the internal SP frame to and from another master station device.

(8) In the communication system of the present embodiment, the value of 4095 described in the VLAN ID may be adopted as the identification information.
In this case, since it is not necessary for one communication device to provide the address value to the other communication device, the transmission / reception sequence of the SP frame becomes simpler than the case where the address value of the communication device is adopted as the identification information.

(9) In the communication system of the present embodiment, one of the first and second communication devices has a VLAN ID value of 4095 generated by the first or second control unit of the own device. It is preferable to transmit one SP frame to the other communication device.
In this way, the other communication device can determine that the SP frame having the value of the VLAN ID of 4095 is the internal SP frame.

(10) In the communication system of the present embodiment, one of the first and second communication devices discards the SP frame whose VLAN ID value is 4095 among the SP frames received from outside the system. It is preferable to do so.
In this way, even if the spoofed communication node transmits an SP frame addressed to the other communication device, the SP frame can be discarded by the one communication device.

(11) The communication device of the present embodiment relates to the communication device constituting the communication system according to the above-mentioned (1) to (10).
Therefore, the communication device of the present embodiment has the same function and effect as the communication system described in (1) to (10) above.

(12) The transfer method of the present embodiment relates to a transfer method executed in the communication device constituting the communication system according to the above-mentioned (1) to (10).
Therefore, the transfer method of the present embodiment has the same effect as that of the communication system described in (1) to (10) above.

<Details of the Embodiment of the present invention>
Hereinafter, the details of the embodiment of the present invention will be described with reference to the drawings. In addition, at least a part of the embodiments described below may be arbitrarily combined.
Hereinafter, embodiments when the SP (slow protocol) is OAM will be described in detail, but as described above, the SP is not limited to OAM and may be, for example, LACP.

<First Embodiment>
[Communication system configuration example]
FIG. 1 is a system configuration diagram showing a configuration example of a communication system according to the first embodiment.
As shown in FIG. 1, in the communication system of the present embodiment, the first and second communication devices 1 and 2, which are a pair of communication devices for exchanging OAM frames, the communication line 3, and the pair of communication devices 1 and 2. It is provided with a relay device 4 interposed between the two.

The first and second communication devices 1 and 2 are communication devices that function as line termination devices, respectively. Therefore, the communication line 3 is terminated at the connection end with the first and second communication devices 1 and 2.
The relay device 4 includes, for example, a repeater that amplifies the transmission signal flowing through the communication line 3 as it is. The number of relay devices 4 to be installed is not limited to two in the example, and may be one or more. The communication devices 1 and 2 may be directly connected to each other by the communication line 3 without the intervention of the relay device 4.

The communication line 3 is composed of a communication cable such as an optical fiber or a coaxial cable. A wireless communication transmission line may be adopted instead of the communication line 3. In this embodiment, it is assumed that the communication line 3 is an optical fiber.
The first communication device 1 located on the upper side of the communication system is communicably connected to the upper network 5, and the second communication device 2 located on the lower side of the communication system is communicably connected to the lower network 6. There is. The lower network 6 is composed of, for example, a home LAN (Local Area Network) or an in-house LAN.

The first and second communication devices 1 and 2 are communication devices capable of transmitting and receiving communication frames including Ethernet frames and corresponding to Ethernet OAM. Therefore, the first and second communication devices 1 and 2 have the function of the link OAM specified in IEEE802.3ah.
Link OAM is an OAM function that is premised on use in P2P (Point to Point) for the purpose of monitoring the physical line and communication status between a pair of Ethernet devices.

In the present embodiment, the OAM frame used for monitoring the communication status between the first and second communication devices 1 and 2, which are the line termination devices of the communication system, is referred to as an "internal OAM frame". Further, the OAM frame used for monitoring the communication status between the communication node (not shown) of the upper network 5 and the communication node (not shown) of the lower network 6 is referred to as an "external OAM frame".
Therefore, in the communication system of the present embodiment, both the internal OAM frame exchanged between the first and second communication devices 1 and 2 which are the communication nodes in the system and the external OAM frame exchanged between the communication nodes outside the system. Coexist.

In the present embodiment, among the pair of communication devices 1 and 2, the communication device 1 that provides its own MAC (Media Access Control) address as the identification information of the internal OAM frame to the other party is referred to as "master station device 1". The communication device 2 to which the MAC address is provided is referred to as a "slave station device 2".
In the example of FIG. 1, the first communication device 1 which is the upper line termination device is the “master station device 1”, and the second communication device 2 which is the lower line termination device is the “slave station device 2”. be.

[Internal configuration of master station device]
FIG. 2 is a block diagram showing an example of the internal configuration of the master station device 1. In FIG. 2, the solid arrow indicates the transmission direction of the communication frame, and the broken line arrow indicates the internal bus of the control signal.
As shown in FIG. 2, the master station apparatus 1 of the present embodiment has an upper interface unit 11, a control unit 12, a reception processing unit 13, a transmission processing unit 14, an opposite side interface unit 15, an uplink buffer 16, and a downlink buffer 17. , And the memory 18 of the reception processing unit 13.

The memory 18 is made of a volatile memory. The memory 18 may be a memory dedicated to the reception processing unit 13, or may be a memory shared with the control unit 12 and the transmission processing unit 14.
The memory 18 is an identification value written in a predetermined frame storage area used by the reception processing unit 13 of the master station apparatus 1 to identify an internal OAM frame (in this embodiment, a MAC DA value of a communication frame, Length / type). It has a storage area for the value of the field and the value of the SubType field (see FIG. 4).

The upper interface unit 11 includes an integrated circuit that executes communication processing of layer 1 and layer 2 with respect to electrical signals in the upstream direction and the downstream direction.
The control unit 12, the reception processing unit 13, and the transmission processing unit 14 are integrated circuits (for example,) that execute communication processing in accordance with a predetermined communication standard such as IEEE 802.3ah for the communication frames in the uplink direction and the downlink direction. MAC chip).

Specifically, the control unit 12 comprises an integrated circuit that executes predetermined information processing according to a computer program, and includes, for example, at least one of a CPU (Central Processing Unit) and an FPGA (Field-Programmable Gate Array). ..
The reception processing unit 13 and the transmission processing unit 14 are composed of logic circuit devices designed to enable specific information processing, and include, for example, at least one of an ASIC (Application Specific Integrated Circuit) and an FPGA.

The interface unit 15 on the opposite side comprises an optical communication device (for example, a pluggable optical transceiver) including an element for transmitting and receiving an optical signal.
The interface unit 15 on the opposite side converts the optical signal received from the optical fiber 3 into a communication frame composed of an electric signal, and outputs the converted communication frame to the reception processing unit 13. The interface unit 15 on the opposite side converts the communication frame from the transmission processing unit 14 into an optical signal, and sends the converted optical signal to the optical fiber 3.

The reception processing unit 13 can execute the "frame transfer process". This process is a process of determining the transfer destination of the communication frame input from the opposite side interface unit 15 based on the identification value of the predetermined frame storage area.
For example, the reception processing unit 13 transfers an OAM frame including the MAC address of the master station device 1 to the control unit 12. The reception processing unit 13 transfers other communication frames (including external OAM frames transmitted by the communication node of the lower network 6) to the uplink buffer 16.

The upper interface unit 11 converts the carrier signal received from the upper network 5 into a communication frame, and outputs the converted communication frame to the downlink buffer 17.
If the uplink buffer 16 has a communication frame, the upper interface unit 11 converts the communication frame into a carrier signal and sends the converted carrier signal to the upper network 5.

If the downlink buffer 17 has a communication frame, the transmission processing unit 14 takes out the communication frame from the downlink buffer 17 while the internal OAM frame is input from the control unit 12, and outputs the communication frame to the opposite interface unit 15.

The control unit 12 can execute "OAM generation processing" as information processing related to OAM. This process is a process of generating a downlink OAM frame used between the master station and the slave station.
The control unit 12 sends the generated OAM frame to the transmission processing unit 14. When the downlink OAM frame is input from the control unit 12, the transmission processing unit 14 outputs the input OAM frame to the opposite side interface unit 15. The interface unit 15 on the opposite side sends the input downlink OAM frame to the optical fiber 3.

The control unit 12 can execute the "address setting process". This process is a process of setting the MAC address value a1 (hereinafter referred to as “address value a1”) of the own device (master station device 1) used for identifying the internal OAM frame in the reception processing unit 13.
Specifically, the control unit 12 stores the address value a1 of its own device in the memory 18 of the reception processing unit 13.

When the slave station device 2 inputs the internal OAM frame of the transmission source from the reception processing unit 13, the control unit 12 executes a predetermined process according to the content of the internal OAM frame as information processing related to the OAM.
For example, in the control unit 12, the slave station device 2 changes the transmission / reception speed of the opposite side interface unit 15 or the upper side interface unit 11 according to the internal OAM frame of the transmission source, or the reception processing unit 13 or the transmission processing unit 14. To stop or start the operation of.

When the OAM event of the internal OAM frame is a LoS (Loss of Signal) event indicating that the optical signal is not received for a predetermined period, the control unit 12 sends the notified LoS event to the parent via the upper network 5 or the like. Transfer to a management device (not shown) of a telecommunications carrier capable of communicating with the station device 1.

[Internal configuration of slave station device]
FIG. 3 is a block diagram showing an example of the internal configuration of the slave station device 2. In FIG. 3, the solid arrow indicates the transmission direction of the communication frame, and the broken line arrow indicates the internal bus of the control signal.
As shown in FIG. 3, the slave station device 2 of the present embodiment has a lower interface unit 21, a control unit 22, a reception processing unit 23, a transmission processing unit 24, an opposite side interface unit 25, an uplink buffer 26, and a downlink buffer 17. , The memory 28 of the reception processing unit 23, and the memory 29 of the transmission processing unit 24.

The memory 28 comprises a volatile memory. The memory 28 may be a memory dedicated to the reception processing unit 23, or may be a memory shared with the control unit 22 and the transmission processing unit 24.
The memory 28 has a storage area of an identification value (in this embodiment, a MAC SA value, a Length / type field value, and a SubType field value) of a frame storage area used by the reception processing unit 23 for determining an internal OAM frame. ..

The memory 29 is made of a volatile memory. The memory 29 may be a memory dedicated to the transmission processing unit 24, or may be a memory shared with the control unit 22 and the reception processing unit 23.
The memory 29 is an identification value written in a predetermined frame storage area used by the transmission processing unit 24 of the slave station device 2 to identify an internal OAM frame (in this embodiment, a MAC DA value of a communication frame, Length / type). It has a storage area for the value of the field and the value of the SubType field (see FIG. 4).

The lower interface unit 21 includes an integrated circuit that executes communication processing of layer 1 and layer 2 with respect to electrical signals in the upstream direction and the downstream direction.
The control unit 22, the reception processing unit 23, and the transmission processing unit 24 are integrated circuits (for example,) that execute communication processing according to a predetermined communication standard such as IEEE 802.3ah for the communication frames in the upstream direction and the downlink direction. MAC chip).

Specifically, the control unit 22 is an integrated circuit that executes predetermined information processing according to a computer program, and includes, for example, at least one of a CPU and an FPGA.
The reception processing unit 23 and the transmission processing unit 24 are composed of logic circuit devices designed to enable specific information processing, and include, for example, at least one of ASIC and FPGA.

The interface unit 25 on the opposite side comprises an optical communication device (for example, a pluggable optical transceiver) including an element for transmitting and receiving an optical signal.
The interface unit 25 on the opposite side converts the optical signal received from the optical fiber 3 into a communication frame composed of an electric signal, and outputs the converted communication frame to the reception processing unit 23. The interface unit 25 on the opposite side converts the communication frame from the transmission processing unit 24 into an optical signal, and sends the converted optical signal to the optical fiber 3.

The reception processing unit 23 can execute the "frame transfer process". This process is a process of determining the transfer destination of the communication frame input from the opposite side interface unit 25 based on the identification value of the predetermined frame storage area.
For example, the reception processing unit 23 transfers an OAM frame including the MAC address of the master station device 1 to the control unit 22. The reception processing unit 23 transfers other communication frames (including external OAM frames transmitted by the communication node of the upper network 5) to the downlink buffer 27.

The lower interface unit 21 converts the carrier signal received from the lower network 6 into a communication frame, and outputs the converted communication frame to the uplink buffer 26.
If the downlink buffer 27 has a communication frame, the lower interface unit 21 converts the communication frame into a carrier signal and sends the converted carrier signal to the lower network 6.

If the uplink buffer 26 has a communication frame, the transmission processing unit 24 takes out the communication frame from the uplink buffer 26 while the internal OAM frame is input from the control unit 22, and outputs the communication frame to the opposite interface unit 25.

The control unit 22 can execute "OAM generation processing" as information processing related to OAM. This process is a process of generating an upstream OAM frame used between the master station and the slave station.
The control unit 22 sends the generated OAM frame to the transmission processing unit 24. When the OAM frame in the upstream direction is input from the control unit 22, the transmission processing unit 24 outputs the input OAM frame to the interface unit 25 on the opposite side. The interface unit 25 on the opposite side sends the input upstream internal OAM frame to the optical fiber 3.

The control unit 22 can execute the "address setting process". This process is a process of setting the address value a1 of the MAC address of the master station device 1 used for identifying the internal OAM frame in the reception processing unit 23 and the transmission processing unit 24.
Specifically, the control unit 12 stores the address value a1 of the master station device 1 notified from the master station device 1 in the memories 28 and 29 of the reception processing unit 23 and the transmission processing unit 24, respectively.

When the master station device 1 inputs the internal OAM frame of the transmission source from the reception processing unit 23, the control unit 22 executes a predetermined process according to the content of the internal OAM frame as information processing related to the OAM.
For example, in the control unit 22, the master station device 1 changes the transmission / reception speed of the opposite side interface unit 25 or the lower side interface unit 21 according to the internal OAM frame of the transmission source, or the reception processing unit 23 or the transmission processing unit 24. To stop or start the operation of.

When the OAM event of the internal OAM frame is a LoS event indicating that the optical signal is not received for a predetermined period, the control unit 22 communicates the notified LoS event with the slave station device 2 via the host network 5 or the like. Transfer to a possible carrier management device (not shown).

[Method of determining internal OAM frame]
FIG. 4 is an explanatory diagram showing an example of a method for determining an internal OAM frame.
In FIG. 4, "MAC DA" means the Destination Address field of the MAC address, and "MAC SA" means the Source Address field of the MAC address.
Here, the value of the MAC address of the master station device 1 is set to "a1", and the value of the MAC address of the slave station device 2 is set to "a2".

The identification conditions 1 and 2 in FIG. 4 are conditions for the master station device 1 and the slave station device 2 to identify the OAM frame from the received communication frame.
That is, the master station device 1 and the slave station device 2 determine that the communication frame satisfying the following identification conditions 1 and 2 is an OAM frame.
Identification condition 1: The value of the Length / Type field is 0x8809 Identification condition 2: The value of the SubType field is 3.

Specifically, the reception processing unit 13 of the master station apparatus 1 determines that the communication frame is an OAM frame when the upstream communication frame input from the opposite interface unit 15 satisfies the identification conditions 1 and 2. judge.
When the downlink communication frame input from the opposite interface unit 25 satisfies the identification conditions 1 and 2, the reception processing unit 23 of the slave station device 2 determines that the communication frame is an OAM frame.

As described above, in the present embodiment, the MAC DA value of 01-80-C2-00-00-02, which is the identification condition of the OAM frame in IEEE802.3, is out of the identification condition of the OAM frame. Has been done.

The identification condition 3 in FIG. 4 is a condition for the master station device 1 to identify the internal OAM frame from the received communication frame.
That is, the master station apparatus 1 determines that the communication frame satisfying the following identification condition 3 in addition to the above identification conditions 1 and 2 is an internal OAM frame.
Identification condition 3: MAC DA is the address value a1 of the own device (master station device 1).

Specifically, the reception processing unit 13 of the master station apparatus 1 sets the communication frame as an internal OAM frame when the upstream communication frame input from the opposite interface unit 15 satisfies the identification conditions 1, 2, and 3. Is determined to be.

The identification condition 4 in FIG. 4 is a condition for the slave station device 2 to identify the internal OAM frame from the received communication frame.
That is, the slave station device 2 determines that the communication frame satisfying the following identification condition 4 in addition to the above identification conditions 1 and 2 is an internal OAM frame.
Identification condition 4: MAC SA is the address value a1 of the master station device 1.

Specifically, the reception processing unit 23 of the slave station device 2 sets the communication frame as an internal OAM frame when the upstream communication frame input from the opposite interface unit 25 satisfies the identification conditions 1, 2, and 4. Is determined to be.

[Communication control by master station device]
FIG. 5 is a flowchart showing an example of communication control executed by the master station device 1.
As shown in FIG. 5, the control unit 12 of the master station device 1 executes the “address setting process” on condition that the own device has started to start (Yes in step ST11) (step ST12).

The address setting process of the master station device 1 is a process in which the control unit 12 of the master station device 1 sets the address value a1 of the own device (master station device 1) in the reception processing unit 13.
Specifically, the control unit 12 of the master station device 1 instructs the reception processing unit 13 to store the address value a1 of the own device in the memory 18.

Next, the control unit 12 of the master station apparatus 1 executes the “OAM generation process” (step ST13). The OAM generation process of the master station apparatus 1 is a process of generating an OAM frame of MAC DA = MAC SA = a1.
In other words, the control unit 12 of the master station device 1 has a communication in which the values of MAC DA and MAC SA are the address value a1 of the own device, the value of the Length / Type field is 0x8809, and the value of the SubType field is 3. Generate a frame.

The control unit 12 of the master station apparatus 1 outputs the generated OAM frame to the transmission processing unit 14. Therefore, the OAM frame of MAC DA = MAC SA = a1 is transmitted to the optical fiber 3 by the interface unit 15 on the opposite side and transmitted to the slave station device 2.

Next, the reception processing unit 13 of the master station apparatus 1 executes the “frame transfer process” (step ST14). The frame transfer process of the master station apparatus 1 is a process of determining an OAM frame having MAC DA = a1 as an internal OAM frame and transferring it to the control unit 12, and transferring other communication frames to the uplink buffer 16.
The other communication frames include an external OAM frame in the uplink direction of MAC DA ≠ a1 in addition to a normal data frame that is not an OAM frame.

[Communication control by slave station device]
FIG. 6 is a flowchart showing an example of communication control executed by the slave station device 2.
As shown in FIG. 6, the reception processing unit 23 of the slave station device 2 performs “address notification processing” when the address value a1 of the master station device 1 is not stored in the memories 28 and 29 (No in step ST21). Is executed (step ST22).

The address notification process of the slave station device 2 is performed by the master station device 1 included in the OAM frame of MAC DA = MAC SA, which is first received by the reception processing unit 23 of the slave station device 2 after the link-up of the interface unit 25 on the opposite side. This is a process of notifying the control unit 22 of the address value a1 of.

Next, the control unit 22 of the slave station device 2 executes the “address setting process” (step ST23). The address setting process of the slave station device 2 is a process in which the control unit 22 of the slave station device 2 sets the notified address value a1 of the master station device 1 in the reception processing unit 23 and the transmission processing unit 24.
Specifically, the control unit 22 of the slave station device 2 instructs the reception processing unit 23 and the transmission processing unit 24 to store the address value a1 of the master station device 1 in the memories 28 and 29.

When the address value a1 of the master station device 1 is stored in the memories 28 and 29 (Yes in step ST21), the processes of the above steps ST22 and ST23 are skipped, and the process proceeds to the next step ST24. ..

Next, the control unit 22 of the slave station device 2 executes the “OAM generation process” (step ST24). The OAM generation process of the slave station device 2 is a process of generating an OAM frame having MAC DA = a1 and MAC SA = a2.
In other words, in the control unit 22 of the slave station device 2, the MAC DA value is the address value a1 of the master station device 1, the MAC SA value is the address value a2 of the own device, and the value of the Length / Type field is. Generates a communication frame with 0x8809 and a SubType field value of 3.

The control unit 22 of the slave station device 2 outputs the generated OAM frame to the transmission processing unit 24. Therefore, the OAM frame having MAC DA = a1 and MAC SA = a2 is transmitted to the optical fiber 3 by the interface unit 25 on the opposite side and transmitted to the master station device 1.

Next, the reception processing unit 23 of the slave station device 2 executes the “frame transfer process” (step ST25). The frame transfer process of the slave station device 2 is a process of determining an OAM frame having MAC SA = a1 as an internal OAM frame and transferring it to the control unit 22, and transferring other communication frames to the downlink buffer 27.
Other communication frames include not only normal data frames that are not OAM frames, but also external OAM frames in the downlink direction of MAC SA ≠ a1.

Next, the transmission processing unit 24 of the slave station device 2 executes the “frame discard processing” (step ST26). The frame discard process of the slave station device 2 is a process of discarding the OAM frame of MAC DA = a1 among the communication frames accumulated in the uplink buffer 26 and transferring the other communication frames to the opposite interface unit 25.
As a result, even if the spoofed communication node belonging to the lower network 6 transmits an OAM frame addressed to the master station device 1, the OAM frame is discarded by the slave station device 2.

[Procedure for sending and receiving OAM frames]
FIG. 7 is a sequence diagram showing an example of an OAM frame transmission / reception procedure performed between the master station device 1 that executes the communication control of FIG. 5 and the slave station device 2 that executes the communication control of FIG.
In FIG. 7, transmission / reception of OAM frames F1 to F4 exchanged between the master station device 1 and the slave station device 2 is repeated at predetermined time (for example, 1 second).

As shown in FIG. 7, the master station device 1 generates an OAM frame F1 with MAC DA = MAC SA = a1 and transmits it in the downlink direction after the own device is activated.
The slave station device 2 that has received the OAM frame F1 learns the address value a1 of the master station device 1 included in the OAM frame F1 of MAC DA = MAC SA. This learning corresponds to the process of storing the address value a1 of the master station device 1 in the memories 28 and 29.

After that, the slave station device 2 generates an OAM frame F2 having MAC DA = a1 and MAC SA = a2, and transmits the OAM frame F2 in the upstream direction.
The reception processing unit 13 of the master station device 1 determines that the OAM frame F2 with MAC DA = a1 is an internal OAM frame (see FIG. 4), and transfers the OAM frame F2 to the control unit 12 (step ST14). Therefore, the master station apparatus 1 that has received the OAM frame F2 executes a predetermined OAM process described in the data field of the OAM frame F2.

After that, the master station device 1 generates an OAM frame F3 with MAC DA = MAC SA = a1 and transmits the OAM frame F3 in the downlink direction.
The reception processing unit 23 of the slave station device 2 determines that the OAM frame F3 of MAC SA = a1 is an internal OAM frame (see FIG. 4), and transfers the OAM frame F3 to the control unit 22 (step ST25). Therefore, the master station apparatus 1 that has received the OAM frame F3 executes a predetermined OAM process described in the data field of the OAM frame F3.

In FIG. 7, the OAM frame F5 is an external OAM frame transmitted by the communication node of the upper network 5 to the communication node of the lower network 6. The OAM frame F5 flows into the communication system from the master station device 1 and reaches the slave station device 2.
However, since the OAM frame F5 is an OAM frame with MAC SA ≠ a1, the reception processing unit 23 of the slave station device 2 transfers the OAM frame F5 to the downlink buffer 27 (step ST25). Therefore, the OAM frame F5 is transmitted to the lower network 6 through the control unit 22 of the slave station device 2.

In FIG. 7, the OAM frame F6 is an external OAM frame transmitted by the communication node of the lower network 6 to the communication node of the upper network 5. The OAM frame F6 flows into the communication system from the slave station device 2 and reaches the master station device 1.
However, since the OAM frame F6 is an OAM frame with MAC DA ≠ a1, the reception processing unit 13 of the master station apparatus 1 transfers the OAM frame F6 to the uplink buffer 16 (step ST14). Therefore, the OAM frame F6 is transmitted to the upper network 5 through the control unit 12 of the master station apparatus 1.

In FIG. 7, the OAM frame F7 is an OAM frame transmitted by a communication node of the lower network 6 (for example, a spoofing communication node) to the master station device 1.
However, since the OAM frame F7 is an OAM frame with MAC DA = a1, the transmission processing unit 24 of the slave station device 2 discards the OAM frame F7 (step ST26). In this way, the OAM frame F7 destined for the master station device 1 transmitted from the communication node of the lower network 6 is discarded by the slave station device 2, so that the master station device 1 cannot be reached.

[Modified example of the first embodiment]
Regarding the slave station device 2 of the first embodiment, if the address value a1 of the master station device 1 once recorded in the memories 28 and 29 remains, there are two types when the slave station device 2 is connected to another master station device 1. The address value of is recorded in the memories 28 and 29.

However, in this case, the address value of the master station device 1 cannot be uniquely determined, and the slave station device 2 cannot send and receive the internal OAM frame to and from the master station device 1.
Therefore, the control unit 22 of the slave station device 2 erases the address value a1 of the master station device 1 in storage from the memories 28 and 29 when the interface unit 25 on the opposite side is linked down. And it is preferable to instruct the transmission processing unit 24.

[Effect of the first embodiment]
According to the communication system of the present embodiment, the first and second communication devices 1 and 2 transfer the internal OAM frame among the OAM frames received from the system to their own control units 12 and 22, and the external OAM frame. Is sent out of the system without being transferred to their own control units 12 and 22.
Therefore, the control units 12 and 22 do not execute information processing for the external OAM frame unrelated to the own device, and the load of information processing related to OAM can be reduced.

In the communication system of the present embodiment, the reception processing units 13 and 23 of the first and second communication devices 1 and 2 have an internal OAM frame based on the identification information included in the received OAM frame. Judge whether or not.

In the communication system of the present embodiment, the address value of one of the first and second communication devices 1 and 2 (for example, the address value of the "MAC address") is adopted as the identification information.
Then, in the communication system of the present embodiment, as an example, the first communication device 1 on the upper side becomes a "master station device" that provides the address value of the own device, and the second communication device 2 on the lower side becomes the master station. It is a "slave station device" to which an address value is provided from the device 1.

In the communication system of the present embodiment, the transmission processing unit 14 of the master station device 1 uses the OAM frame generated by the control unit 12 of the own device, in which both the destination and the transmission source are the address values of the own device, as the slave station device 2. Send to.
Therefore, the control unit 12 of the slave station device 2 can learn the address value of the master station device 1 by using an OAM frame in which the address values of the destination and the source are the same. Further, the reception processing unit 23 of the slave station device 2 can determine that the OAM frame whose source address value is the address value of the master station device 1 is an internal OAM frame.

In the communication system of the present embodiment, in the transmission processing unit 24 of the slave station device 2, the destination is the address value of the master station device 1 and the transmission source is the address value of the own device, which is generated by the control unit 22 of the own device. The OAM frame is transmitted to the master station device 1.
Therefore, the reception processing unit 13 of the master station apparatus can determine that the OAM frame whose destination address value is the address value of the master station apparatus 1 is an internal OAM frame.

In the communication system of the present embodiment, the transmission processing unit 24 of the slave station device 2 discards the OAM frame whose destination address value is the address value of the master station device 1 among the OAM frames received from outside the system.
Therefore, even if the spoofing communication node transmits an OAM frame addressed to the master station device 1, the OAM frame can be discarded by the slave station device 2.

In the communication system of the present embodiment, the slave station device 2 is a memory for storing the address value of the master station device 1 included in the OAM frame first received from the master station device 1 after linking up with the master station device 1. The storage unit) 28, 29 is provided, and the memory 28, 29 erases the address value of the master station device 1 according to the link down with the master station device 1.
Therefore, the slave station device 2 can send and receive the internal OAM frame to and from another master station device 1.

<Second Embodiment>
[Communication system configuration example]
FIG. 8 is a system configuration diagram showing a configuration example of the communication system according to the second embodiment.
As shown in FIG. 8, in the communication system of the present embodiment, the first and second communication devices 40A and 40B, which are a pair of communication devices for exchanging OAM frames, the communication line 3, and the pair of communication devices 40A and 40B. It is provided with a relay device 4 interposed between the two.

The first and second communication devices 40A and 40B are communication devices that function as line termination devices, respectively. Therefore, the communication line 3 is terminated at the connection end with the first and second communication devices 40A and 40B.
The relay device 4 includes, for example, a repeater that amplifies the transmission signal flowing through the communication line 3 as it is. The number of relay devices 4 to be installed is not limited to two in the example, and may be one or more. The communication devices 40A and 40B may be directly connected to each other by the communication line 3 without the intervention of the relay device 4.

The communication line 3 is composed of a communication cable such as an optical fiber or a coaxial cable. Instead of the communication line 3, a transmission line for wireless communication can be adopted. Also in this embodiment, it is assumed that the communication line 3 is an optical fiber.
The first communication device 40A located on the upper side of the communication system is communicably connected to the upper network 5, and the second communication device 40B located on the lower side of the communication system is communicably connected to the lower network 6. There is. The lower network 6 is composed of, for example, a home LAN or an in-house LAN.

The first and second communication devices 40A and 40B are communication devices capable of transmitting and receiving communication frames including Ethernet frames and corresponding to Ethernet OAM. Therefore, the first and second communication devices 40A and 40B have the function of the link OAM specified in IEEE802.3ah.
Link OAM is an OAM function that is premised on use in P2P for the purpose of monitoring the physical line and communication status between a pair of Ethernet devices.

Also in this embodiment, the OAM frame used for monitoring the communication status between the first and second communication devices 40A and 40B, which are the line termination devices of the communication system, is referred to as an "internal OAM frame". Further, an OAM frame used for monitoring communication between a communication node (not shown) of the upper network 5 and a communication node (not shown) of the lower network 6 is referred to as an "external OAM frame".
Also in the communication system of the present embodiment, both the internal OAM frame exchanged between the first and second communication devices 40A and 40B, which are communication nodes in the system, and the external OAM frame exchanged between the communication nodes outside the system are used. Coexist.

As will be described later, in the present embodiment, the ID value of the VLAN (Virtual Local Area Network) ID is used as the identification information of the internal OAM frame, not the MAC address of the communication devices 40A and 40B.
Therefore, there is no distinction between a master station and a slave station in the pair of communication devices 40A and 40B. In the following, the first communication device 40A may be abbreviated as "communication device 40A", and the second communication device 40B may be abbreviated as "communication device 40B". The generic name thereof is described as "communication device 40".

[Internal configuration of communication device]
FIG. 9 is a block diagram showing an example of the internal configuration of the communication device 40. In FIG. 9, the solid arrow indicates the transmission direction of the communication frame, and the broken line arrow indicates the internal bus of the control signal.
As shown in FIG. 9, the communication device 40 of the present embodiment includes an outer interface unit 41, a control unit 42, a reception processing unit 43, a transmission processing unit 44, an opposite interface unit 45, a buffer 46, and a buffer 47.

When the communication device 40 is the upper communication device 40A, the outer interface unit 41 adopts an interface unit conforming to the communication standard of the upper network 5.
When the communication device 40 is the lower communication device 40B, the outer interface unit 41 adopts an interface unit conforming to the communication standard of the lower network 6.

When the communication device 40 is the upper communication device 40A, the buffer 46 is an uplink buffer in which uplink communication frames are stored, and the buffer 47 is a downlink buffer in which downlink communication frames are stored.
When the communication device 40 is the lower communication device 40B, the buffer 46 is a downlink buffer in which downlink communication frames are stored, and the buffer 47 is an uplink buffer in which uplink communication frames are stored.

The outer interface unit 41 includes an integrated circuit that executes communication processing of layer 1 and layer 2 with respect to electrical signals in the upstream direction and the downstream direction.
The control unit 42, the reception processing unit 43, and the transmission processing unit 44 are integrated circuits (for example,) that execute communication processing in accordance with a predetermined communication standard such as IEEE 802.3ah for the communication frames in the uplink direction and the downlink direction. MAC chip).

Specifically, the control unit 42 comprises an integrated circuit that executes predetermined information processing according to a computer program, and includes, for example, at least one of a CPU and an FPGA.
The reception processing unit 43 and the transmission processing unit 44 are composed of logic circuit devices designed to enable specific information processing, and include, for example, at least one of ASIC and FPGA.

The interface unit 45 on the opposite side comprises an optical communication device (for example, a pluggable optical transceiver) including an element for transmitting and receiving an optical signal.
The interface unit 45 on the opposite side converts the optical signal received from the optical fiber 3 into a communication frame composed of an electric signal, and outputs the converted communication frame to the reception processing unit 43. The interface unit 45 on the opposite side converts the communication frame from the transmission processing unit 44 into an optical signal, and sends the converted optical signal to the optical fiber 3.

The reception processing unit 43 can execute the "frame transfer process". This process is a process of determining the transfer destination of the communication frame input from the opposite side interface unit 45 based on the identification value of the predetermined frame storage area (VLAN ID in this embodiment).
For example, the reception processing unit 43 transfers an OAM frame with VLAN ID = 4095 to the control unit 42. The reception processing unit 43 transfers other communication frames (including external OAM frames transmitted by the communication node of the upper network 5 or the lower network 6) to the buffer 46.

The outer interface unit 41 converts the carrier signal received from the upper network 5 or the lower network 6 into a communication frame, and outputs the converted communication frame to the buffer 47.
If the buffer 46 has a communication frame, the outer interface unit 41 converts the communication frame into a carrier signal and sends the converted carrier signal to the upper network 5 or the lower network 6.

If the buffer 47 has a communication frame, the transmission processing unit 44 takes out the communication frame from the buffer 47 while the internal OAM frame is input from the control unit 22, and outputs the communication frame to the opposite interface unit 45.

The control unit 42 can execute "OAM generation processing" as information processing related to OAM. This process is a process for generating an OAM frame with VLAN ID = 4095, which is used between the communication devices 40A and 40B.
The control unit 42 sends the generated OAM frame to the transmission processing unit 44. When the OAM frame is input from the control unit 42, the transmission processing unit 44 outputs the input OAM frame to the interface unit 45 on the opposite side. The interface unit 45 on the opposite side sends the input OAM frame to the optical fiber 3.

When the internal OAM frame with the VLAN ID = 4095 is input from the reception processing unit 13, the control unit 42 executes a predetermined process according to the content of the internal OAM frame as information processing related to the OAM.
For example, the control unit 12 changes the transmission / reception speed of the opposite side interface unit 45 or the outer interface unit 41, or stops or starts the operation of the reception processing unit 43 or the transmission processing unit 44 according to the internal OAM frame. ..

When the OAM event of the internal OAM frame is a LoS event indicating that the optical signal is not received for a predetermined period, the control unit 42 communicates the notified LoS event with the master station device 1 via the host network 5 or the like. Transfer to a possible carrier management device (not shown).

[Method of determining internal OAM frame]
FIG. 10 is an explanatory diagram showing an example of a method for determining an internal OAM frame.
In FIG. 10, "MAC DA" means the Destination Address field of the MAC address, and "MAC SA" means the Source Address field of the MAC address.

The identification conditions 1 to 3 in FIG. 10 are conditions for the communication device 40 to identify the OAM frame from the received communication frame.
That is, the communication device 40 determines that the communication frame satisfying the following identification conditions 1 to 3 is an OAM frame.
Identification condition 1: The MAC DA value is 01-80-C2-00-00-02 Identification condition 2: The value of the Length / Type field is 0x8809 Identification condition 3: The value of the SubType field is 3. thing

Specifically, the reception processing unit 43 of the communication device 40 determines that the communication frame is an OAM frame when the communication frame input from the opposite interface unit 45 satisfies the identification conditions 1 to 3.

As described above, in the present embodiment, the MAC DA value, which is the identification condition of the OAM frame in IEEE802.3, is 01-80-C2-00-00-02 as it is.

The identification condition 4 in FIG. 10 is a condition for the communication device 40 to identify the internal OAM frame from the received communication frame.
That is, the communication device 40 determines that the communication frame satisfying the following identification condition 4 in addition to the above identification conditions 1 to 3 is an internal OAM frame.
Identification condition 4: The value of the VLAN ID included in the Tag field is 4095.

Specifically, the reception processing unit 43 of the communication device 40 determines that the communication frame is an internal OAM frame when the communication frame input from the opposite interface unit 45 satisfies the identification conditions 1 to 4.

[Procedure for sending and receiving OAM frames]
FIG. 11 is a sequence diagram showing an example of an OAM frame transmission / reception procedure performed between the communication device 40A and the communication device 40B.
In FIG. 11, the transmission / reception of the OAM frames F11 to F13 exchanged between the communication device 40A and the communication device 40B is repeated every predetermined time (for example, 1 second).

As shown in FIG. 11, the communication device 40A on the upper side generates an OAM frame F11 with VLAN ID = 4095 and transmits it in the downlink direction.
The reception processing unit 43 of the lower communication device 40B determines that the OAM frame F11 with VLAN ID = 4095 is an internal OAM frame, and transfers the OAM frame F11 to the control unit 42. Therefore, the communication device 40B that has received the OAM frame F11 executes a predetermined OAM process described in the data field of the OAM frame F11.

After that, the communication device 40B on the lower side generates an OAM frame F12 having a VLAN ID = 4095 and transmits the OAM frame F12 in the upstream direction.
The reception processing unit 43 of the communication device 40A on the upper side determines the OAM frame F12 having the VLAN ID = 4095 as the internal OAM frame, and transfers the OAM frame F12 to the control unit 42. Therefore, the communication device 40A that has received the OAM frame F12 executes a predetermined OAM process described in the data field of the OAM frame F12.

In FIG. 11, the OAM frame F14 is an external OAM frame transmitted by the communication node of the upper network 5 to the communication node of the lower network 6. The OAM frame F14 flows into the communication system from the communication device 40A and reaches the communication device 40B.
However, since the OAM frame F14 is an OAM frame with VLAN ID ≠ 4095, the reception processing unit 43 of the communication device 40B transfers the OAM frame F14 to the buffer 46. Therefore, the OAM frame F14 is transmitted to the lower network 6 through the control unit 42 of the communication device 40B.

In FIG. 11, the OAM frame F15 is an external OAM frame transmitted by the communication node of the lower network 6 to the communication node of the upper network 5. The OAM frame F15 flows into the communication system from the communication device 40B and reaches the communication device 40A.
However, since the OAM frame F15 is an OAM frame with a VLAN ID ≠ 4095, the reception processing unit 43 of the communication device 40A transfers the OAM frame F15 to the buffer 46. Therefore, the OAM frame F15 is transmitted to the upper network 5 through the control unit 42 of the communication device 40A.

In FIG. 11, the OAM frame F16 is an OAM frame transmitted by a communication node of the lower network 6 (for example, a spoofing communication node) to the communication device 40A.
However, since the OAM frame F16 is an OAM frame with VLAN ID = 4095, the transmission processing unit 44 of the communication device 40A discards the OAM frame F16. As described above, the OAM frame F16 addressed to the communication device 40A transmitted from the communication node of the lower network 6 is discarded by the communication device 40B, so that the communication device 40A cannot be reached.

[Effect of the second embodiment]
According to the communication system of the present embodiment, the first and second communication devices 40A and 40B transfer the internal OAM frame among the OAM frames received from the system to their own control unit 42, and transfer the external OAM frame to their own control unit 42. It is sent out of the system without being transferred to the control unit 42 of.
Therefore, the control unit 42 does not execute the information processing for the external OAM frame unrelated to the own device, and the load of the information processing related to the OAM can be reduced.

In the communication system of the present embodiment, the reception processing unit 43 of the first and second communication devices 40A and 40B determines whether or not the received OAM frame is an internal OAM frame based on the identification information included in the received OAM frame. Is determined.

In the communication system of the present embodiment, the value of 4095 described in the VLAN ID is adopted as the identification information.
In this case, since it is not necessary for one communication device 40A to provide an address value to the other communication device 40B, transmission / reception of an OAM frame is performed as compared with the case of the first embodiment in which the address value of the communication device is adopted as the identification information. The sequence becomes simpler.

In the communication system of the present embodiment, one of the communication devices 40A (40B) uses the OAM frame generated by the control unit 42 of the own device and having a VLAN ID value of 4095 as the other communication device 40B. Send to (40A).
Therefore, the other communication device 40B (40A) can determine that the OAM frame whose VLAN ID value is 4095 is an internal OAM frame.

In the communication system of the present embodiment, the communication device 40A (40B) of the communication device 40 discards the OAM frame whose VLAN ID value is 4095 among the OAM frames received from outside the system.
Therefore, even if the spoofing communication node transmits an OAM frame addressed to the other communication device 40B (40A), the OAM frame can be discarded by the one communication device 40A (40B).

<Other variants>
The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. The scope of rights of the present invention is indicated by the scope of claims and includes all modifications within the meaning and scope equivalent to the scope of claims.

In the above-described embodiment, the reception processing units 13, 23, 43 input all communication frames (including external OAM frames) other than the internal OAM frames received from the system into the buffers 16, 27, 46. Therefore, the electric signal of the external OAM frame is not input to the control units 12, 22, and 42.
As a result, the control units 12, 22, and 42 do not execute information processing for the external OAM frame unrelated to the own device, and the load of information processing related to OAM is reduced.

As a modification of the above-described embodiment, the reception processing units 13, 23, 43 attach the flag information indicating that information processing is not required to the electric signal of the external OAM frame received from the system, and the control unit 12. , 22, 42 may be input.
In this case, the control units 12, 22, and 42 do not read out the flagged electric signals input from the reception processing units 13, 23, 43, that is, do not execute information processing of the input flagged electric signals. You can dispose of it.

Even in this case, since the control units 12, 22, and 42 do not execute information processing according to the external OAM frame, the load of information processing related to OAM can be reduced.
However, in the process of inputting an electric signal with a flag (external OAM frame) to the control units 12, 22, 42, the control units 12, 22, 42 need to determine the flag, so that the load of information processing is reduced. From the viewpoint, the above-described embodiment in which the electric signals constituting the external OAM frame are not input to the control units 12, 22, and 42 is preferable.

As is clear from the above, in the present disclosure, "without transferring the external OAM frame to the control unit" corresponds to the process of not "substantially" transferring the external OAM frame to the control unit, that is, the external OAM frame. The transfer processing may be such that the control unit does not execute information processing, and in addition to the processing in which the electric signal of the external OAM frame is not input to the control unit, the electric signal of the external OAM frame with flag information that does not require information processing is input. The process of inputting to the control unit is also included.

<Applicable communication protocol>
In the above-described embodiment (including a modification), the case where the SP (slow protocol) is OAM is exemplified, but the SP is not limited to OAM, and may be, for example, LACP.
In a communication system that employs LACP, "OAM" is read as "LACP" in the description of the above-described embodiment (including a modification), and one of the OAM frame identification conditions (Subtype field value = 0x03). ) May be changed to one of the LACP frame identification conditions (Subtype field value = 0x01).

<Communications system from another point of view>
The disclosure includes the communication systems described below.

[Additional Notes]
A communication system including first and second communication devices that receive an external SP frame defined below from outside the system and exchange an internal SP frame defined below.
The first communication device is
The first control unit that processes information related to SP,
The external SP frame received from outside the system and the first transmission processing unit that transmits the internal SP frame generated by the first control unit of the own device into the system.
It has a first reception processing unit that receives SP frames from within the system.
The second communication device is
The second control unit that processes information related to SP,
A second transmission processing unit that transmits the external SP frame received from outside the system and the internal SP frame generated by the second control unit of the own device into the system.
It has a second reception processing unit that receives SP frames from within the system.
Of the SP frames received from within the system, the first reception processing unit transfers the internal SP frame to the first control unit, and sends the external SP frame out of the system without transferring it to the first control unit. death,
Of the SP frames received from within the system, the second reception processing unit transfers the internal SP frame to the second control unit, and sends the external SP frame out of the system without transferring it to the second control unit. Communication system.
Internal SP frame: SP frame exchanged between communication nodes in the system External SP frame: SP frame exchanged between communication nodes outside the system

1 First communication device (master station device)
2 Second communication device (slave station device)
3 Communication line (optical fiber)
4 Relay device 5 Upper network 6 Lower network 11 Upper interface unit 12 Control unit (1st control unit)
13 Receive processing unit 14 Transmission processing unit 15 Opposite side interface unit 16 Uplink buffer
17 Down buffer 18 Memory (storage unit)
21 Lower interface unit 22 Control unit (second control unit)
23 Receive processing unit 24 Transmission processing unit 25 Opposite side interface unit 26 Upstream buffer 27 Downstream buffer 28 Memory (storage unit)
29 Memory (storage unit)
40 Communication device 40A First communication device (upper side)
40B 2nd communication device (lower side)
41 Outer interface unit 42 Control unit 43 Receive processing unit 44 Transmission processing unit 45 Opposite side interface unit 46 Buffer 47 Buffer

Claims (8)

A communication system including a master station device and a slave station device that receives an external SP frame defined below from outside the system and exchanges an internal SP frame defined below.
The master station device is a communication device that provides the address value of the own device to the slave station device.
The slave station device is a communication device to which the address value of the master station device is provided from the master station device.
The slave station device is
An uplink SP frame whose destination is the address value of the master station device and whose source is the address value of its own device is transmitted into the system.
The master station device is
Of the upstream SP frames received from within the system, the internal SP frame whose destination is the address value of the own device is transferred to the first control unit of the own device that processes information about the SP, and the destination is the address of the own device. The external SP frame that is not a value is sent out of the system without being transferred to the first control unit.
The master station device is
A downlink SP frame whose destination and source are the address values of the own device is transmitted into the system, and the system is transmitted.
The slave station device is
Of the downlink SP frames received from within the system, the transmission source transfers the internal SP frame, which is the address value of the master station device, to the second control unit of the own device that processes information regarding the SP, and the transmission source causes the transmission. A communication system that sends an external SP frame that is not the address value of the master station device to the outside of the system without transferring it to the second control unit.
Internal SP frame: Exchanged between communication nodes in the system, which are identified by the fact that the value of Destination Address or Source Address is the address value of the master station device and that the values of Length / Type and Subtype are predetermined values. SP frame external SP frame: SP frame exchanged between communication nodes outside the system, which is identified by the values of Destination Address, Length / Type, and Subtype being predetermined values. The slave station device is
The communication system according to claim 1 , wherein the address value of the master station device is learned by an SP frame in which the destination and the source of the first reception after linking up with the master station device have the same address value. A master station device that receives an external SP frame defined below from outside the system and replaces the internal SP frame defined below with a slave station device in the system.
The master station device is a communication device that provides the address value of the own device to the slave station device.
The slave station device is a communication device to which the address value of the master station device is provided from the master station device.
The master station device is
A reception processing unit that processes information about upstream communication frames received from within the system,
A transmission processing unit that processes information about downlink communication frames transmitted into the system,
An uplink buffer that stores uplink communication frames to be transmitted outside the system,
It is equipped with a first control unit that processes information related to SP.
The transmission processing unit
A downlink SP frame whose destination and source are the address values of its own device generated by the first control unit is transmitted into the system.
The reception processing unit
Of the upstream SP frames received from within the system, the internal SP frame whose destination is the address value of its own device is transferred to the first control unit, and the external SP frame whose destination is not the address value of its own device is said. Master station device to transfer to the uplink buffer.
Internal SP frame: Exchanged between communication nodes in the system, which are identified by the fact that the value of Destination Address or Source Address is the address value of the master station device and that the values of Length / Type and Subtype are predetermined values. SP frame to be
External SP frame: SP frame exchanged between communication nodes outside the system, which is identified by the predetermined values of Destination Address, Length / Type, and Subtype. A slave station device that receives the external SP frame defined below from outside the system and replaces the internal SP frame defined below with the master station device in the system.
The master station device is a communication device that provides the address value of the own device to the slave station device.
The slave station device is a communication device to which the address value of the master station device is provided from the master station device.
The slave station device is
A reception processing unit that processes information about downlink communication frames received from within the system,
A transmission processing unit that processes information for upstream communication frames transmitted into the system,
A downlink buffer that stores downlink communication frames to be transmitted outside the system,
It is equipped with a second control unit that processes information related to SP.
The transmission processing unit
An upstream SP frame generated by the second control unit, whose destination is the address value of the master station device and whose source is the address value of its own device, is transmitted into the system.
The reception processing unit
Of the downlink SP frames received from within the system, the source transfers the internal SP frame, which is the address value of the master station device, to the second control unit, and the source is not the address value of the master station device. A slave station device that transfers the external SP frame to the downlink buffer.
Internal SP frame: Exchanged between communication nodes in the system, which are identified by the fact that the value of Destination Address or Source Address is the address value of the master station device and that the values of Length / Type and Subtype are predetermined values. SP frame to be
External SP frame: SP frame exchanged between communication nodes outside the system, which is identified by the predetermined values of Destination Address, Length / Type, and Subtype. The transmission processing unit
The slave station device according to claim 4 , wherein the SP frame whose destination address value is the address value of the master station device is discarded among the upstream SP frames received from outside the system. Further having a storage unit for storing the address value of the master station device, which is included in the SP frame first received from the master station device after linking up with the master station device.
The storage unit is
The slave station device according to claim 4 or 5 , which erases the address value of the master station device according to the link down with the master station device. A communication method executed by a master station device that receives an external SP frame defined below from outside the system and exchanges the internal SP frame defined below with a slave station device in the system.
The master station device is a communication device that provides the address value of the own device to the slave station device.
The slave station device is a communication device to which the address value of the master station device is provided from the master station device.
A step in which the master station device transmits a downlink SP frame in which the destination and the source are the address values of the own device into the system.
Among the uplink SP frames received from the system, the master station device transfers the internal SP frame whose destination is the address value of the own device to the first control unit of the own device that processes information about the SP. A communication method including a step of transmitting the external SP frame whose destination is not the address value of the own device to the outside of the system without transferring it to the first control unit.
Internal SP frame: Exchanged between communication nodes in the system, which are identified by the fact that the value of Destination Address or Source Address is the address value of the master station device and that the values of Length / Type and Subtype are predetermined values. SP frame to be
External SP frame: SP frame exchanged between communication nodes outside the system, which is identified by the predetermined values of Destination Address, Length / Type, and Subtype. A communication method executed by a slave station device that receives an external SP frame defined below from outside the system and exchanges the internal SP frame defined below with a master station device in the system.
The master station device is a communication device that provides the address value of the own device to the slave station device.
The slave station device is a communication device to which the address value of the master station device is provided from the master station device.
A step in which the slave station device transmits an uplink SP frame in which the destination is the address value of the master station device and the source is the address value of the own device, and
Among the downlink SP frames received from the system by the slave station device, the internal SP frame whose source is the address value of the master station device is used as the second control unit of the own device that processes information regarding the SP. A communication method including a step of transferring and transmitting the external SP frame whose source is not the address value of the master station device to the outside of the system without transferring it to the second control unit.
Internal SP frame: Exchanged between communication nodes in the system, which are identified by the fact that the value of Destination Address or Source Address is the address value of the master station device and that the values of Length / Type and Subtype are predetermined values. SP frame to be
External SP frame: SP frame exchanged between communication nodes outside the system, which is identified by the predetermined values of Destination Address, Length / Type, and Subtype.

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