JP2009194623A - Ethernet optical access device and ethernet maintenance redundance method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To actualize a maintenance function which is operable in the Ethernet layer in an optical access section and to redundantly constitute the access section using the maintenance function in the Ethernet layer. <P>SOLUTION: In an Ethernet optical access device which provides an OSU and an ONU connected through an optical line as Ethernet transmission lines, the OSU is configured to pass Ethernet OAM frames of a user and Ethernet OAM frames of a network, and has the maintenance function capable of grasping the state of the system in the Ethernet layer below IP and a redundancy function of setting one selected Ethernet transmission line between the plurality of Ethernet transmission lines usable. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an Ethernet (registered trademark) in an optical access section between an optical subscriber line unit (OSU) and an optical network unit (ONU) connected via an optical line. ) An Ethernet optical access apparatus having a maintenance function operable at a layer, and an Ethernet maintenance redundancy method for redundantly configuring an optical access section using an Ethernet layer maintenance function.

Conventionally, an access device connecting access sections has a maintenance function using a protocol such as SNMP (Simple network management protocol) in the IP layer in order to grasp the state of the device and the line. Moreover, in order to ensure reliability by timely use of a plurality of routes, there was a redundant function by separately installing a route selection by a routing protocol using IP packets and an application operating in an upper layer (Patent Document 1). .
Japanese Patent No. 3825674

  However, in the access device that connects the conventional access sections, the system uses the maintenance function and the redundancy function of the IP layer. And only a higher layer than the corresponding layer. In addition, there are some which provide Ethernet, which is a virtual lower layer, by means of encapsulation, tag technology, etc., but the use of layer 2 is restricted and the bandwidth of the used line has to be reduced.

  In addition, in order to exchange control signals through different communication paths and methods, complicated mechanisms and mechanisms are required.

  The maintenance function (monitoring / alarm function) only for the access section was based on the detection of frame, cell, or signal loss, but it is a dedicated maintenance function that can be used only in the access section. Application of was difficult. As a maintenance function applicable to the wide area network, there is a method of using the maintenance function of the IP layer as described above. However, in order to realize a wide area network service in a layer lower than the layer used in the maintenance function. Has a large limitation and could not provide a wide area network service of Ethernet layer with maintenance function.

  The present invention relates to an Ethernet optical access apparatus capable of realizing a maintenance function operable in the Ethernet layer in the optical access section, and an Ethernet maintenance redundancy method capable of redundantly configuring the access section using the maintenance function of the Ethernet layer. The purpose is to provide.

  A first invention is an Ethernet optical access apparatus that provides an OSU and an ONU connected via an optical line as an Ethernet transmission line, and the OSU passes a user frame, a user Ethernet OAM frame, and a network Ethernet OAM frame. A configuration with a maintenance function that can grasp the status of the system at an Ethernet layer lower than IP, and a redundant function that enables one of the Ethernet transmission lines to be set to be usable It is.

  The maintenance function is configured to grasp a state by transmitting a periodic communication frame and a communication frame generated at any time and performing an operation corresponding to the received communication frame. In addition, the maintenance function changes the management state of its own device according to the reception fact of the received communication frame, the frame contents, and the continuous reception mode associated with the reception of a plurality of communication frames, and transfers the received communication frame. In this configuration, discarding is performed, and a new communication frame is generated and transmitted.

  According to a second aspect of the present invention, there is provided an Ethernet maintenance redundancy method in which an OSU and an ONU connected via an optical line are provided as an Ethernet transmission line, and an optical access section is configured redundantly using a maintenance function of the Ethernet layer. Frame, user Ethernet OAM frame, and network Ethernet OAM frame are passed, maintenance function step that can grasp system status at lower Ethernet layer than IP, and selected from multiple Ethernet transmission lines A redundant function step for setting one Ethernet transmission line to be usable.

  The maintenance function step transmits a periodic communication frame and a communication frame generated as needed, and grasps the state by performing an operation corresponding to the received communication frame. In addition, the maintenance function step changes the management state of its own device according to the reception fact of the received communication frame, the frame contents, and the continuous reception mode associated with the reception of a plurality of communication frames, and transfers the received communication frame. Or a new communication frame is generated and transmitted.

  In the IP network, the maintenance function and the redundancy function are realized by the Ethernet layer in the IP network, so that high maintainability and redundancy are ensured, and at the same time, the upper layers such as the Ethernet layer and the IP layer are provided for the access system user. It can be used without restriction. In addition to IP layer addresses and protocols, protocols and services that are normally used by general users can be used without limitation in the Ethernet layer. Furthermore, it is possible to secure Ethernet frame communication with a high degree of freedom, to realize completely free packet communication at the IP layer, and to expand the usage range of general users.

  In addition, for the frame of a general user, the encapsulation and tagging that caused the compression of the used line band are not required, and the communication can be transmitted as it is, and the used line band can be secured.

FIG. 1 shows an embodiment of an Ethernet optical access device of the present invention.
In the figure, an OSU 10 and an ONU 20 which are Ethernet optical access devices of the present invention are connected via an optical line 31 and have an Ethernet OAM (Operation Administration and Management) function. An upper node (SW) 32 on the network side is connected to the OSU 10, and a user terminal 33 is connected to the ONU 20.

  The OSU 10 includes an SNI port 11 connected to an upper node (SW) 32 and an OSU port 14 connected to an optical line 31. Between the SNI port 11 and the OSU port 14, a line control unit is sequentially installed from the SNI port side. (Omitted), the frame controller 12, the line controller (omitted), and the optical / electrical converter 13 are connected. An Ethernet OAM processing unit 15, a switching control unit 16 and a monitoring control / alarm processing unit 17 are connected to the frame control unit 12. The Ethernet OAM processing unit 15, the switching control unit 16, and the monitoring control / alarm processing unit 17 are connected to each other. Similarly, the ONU 20 includes a UNI port 21 connected to the user terminal 33 and an ONU port 24 connected to the optical line 31, and a line control unit (omitted), a frame control unit 22, a line control unit (omitted), optical / Electric conversion unit 23 is connected, and Ethernet control unit 25, switching control unit 26 and monitoring control / alarm processing unit 27 are connected to frame control unit 22.

  Here, the OSU 10 permits passage of the user frame, the user Ethernet OAM frame, and the network Ethernet OAM frame at Layer 2. That is, the Ethernet OAM frame of the network is transmitted between the upper node (SW) on the network side and the Ethernet OAM processing unit 15 of the OSU 10, and between the upper node (SW) on the network side and the Ethernet OAM processing unit 25 of the ONU 20. Are transmitted and received between the Ethernet OAM processing unit 15 and the Ethernet OAM processing unit 25 of the ONU 20. Further, a control Ethernet frame is transmitted and received between the monitoring control / alarm processing unit 17 of the OSU 10 and the monitoring control / alarm processing unit 27 of the ONU 20.

  The Ethernet OAM applied to the optical access section has the following functions. The CC (Continuity Check) function transmits a connectivity check frame from the SNI port 11 and OSU port 14 of the OSU 10 and the ONU port 24 of the ONU 20 every 0.1 second, 1 second, 10 seconds or 60 seconds. Check the reception status of the connectivity check frame, and consider that a frame not received at a fixed period with respect to the transmission cycle is a communication path error or an unconnected or power-off or silent failure error of the opposite device. This is a function that always recognizes the normal operation state of the communication path and the opposite device, assuming that an abnormal state is recovered when a connectivity confirmation frame is received at a certain period from the state in which the communication device is present.

  In addition, regarding the state regarded as an abnormality, the state information of the connectivity confirmation frame is changed and transmitted to transmit the abnormality detection to the opposite device (RDI function). Further, when a connectivity confirmation frame whose status information is changed is received from the opposite device, the opposite device detects an abnormality and grasps that there is an abnormality in the communication direction from the own device to the opposite device.

  The opposing device only needs to be logically connected, and can be applied to a connection form in which a plurality of Ethernet layer devices are relayed. Furthermore, the CC function can check connectivity with a plurality of counter devices that are logically connected.

  When the link down of the UNI port 21 of the ONU 20 is detected, the AIS function continues to transmit the link down detection alarm as a warning transfer frame to the opposite device whose connectivity is to be confirmed in a cycle of 1 second or 60 seconds. The opposing device that has received the frame has a function of grasping the link-down state of the UNI port 21 of the ONU 20 and grasping the recovery of the link-down state when no alarm transfer frame is received.

  The LB (Loopback) function transmits a loopback frame as a connection confirmation at any time, such as when a device is installed, and returns a reception completion frame when receiving a loopback frame at the opposite device, and receives this reception completion frame. This is a function for confirming connection.

  The LM (Loss Monitor) function is a function for confirming the frame arrival quality by transmitting two or more loss monitor frames and comparing the number of transmission frames with the number of received frames in the opposite device as the frame arrival quality confirmation at any time. .

  The DM (Delay Monitor) function transmits at least one delay monitor frame as a frame delay quality confirmation at any time, returns a response frame when receiving a delay monitor frame at the opposite device, and until this response frame is received This is a function for confirming the frame delay quality by measuring the round trip time.

  Further, the maintenance function can realize the CC function and the like in the Ethernet layer between the ONU port 24 of the ONU 20 and the upper node (SW) 32 connected to the SNI port 11 of the OSU 10, and the OSU 10 The Ethernet OAM frame used in the above is recognized as a network maintenance frame and transmitted (transferred).

  The control Ethernet frame is periodically transmitted and received between the OSU 10 and the ONU 20, and is immediately transmitted when an abnormality or alarm is detected or a setting is changed. The ONU 20 transmits its own device status to the OSU 10, and the OSU 10 The setting information is transmitted to the ONU 20.

  When such an Ethernet OAM is used and the optical access section (between the OSU 10 and the ONU 20) is duplexed, the switching control units 16 and 26 that switch operating systems triggered by detection of a failure or the like in the optical access section Operation can be continued. That is, in the case of a redundant configuration, one OSU and the other OSU grasp each other's status information via a back wire board of a casing different from the frame communication path, and use one OSU as the active system. The OSU is controlled as a non-operation system. Then, the switching control unit 16 of each OSU sets the ONU of the opposite connection as the active system and the non-operating system, respectively, and when an abnormality is detected in the operating OSU, the ONU and its route, the OSU and the ONU are set as the non-operating system. And control to switch the other OSU and ONU to the active system.

  FIG. 2 shows a processing procedure of the frame control unit 12 and the Ethernet OAM processing unit 15 of the OSU 10. Here, the management end point of the maintenance function is referred to as MEP (Maintenance Entity Group) end point, and the connectivity confirmation frame is referred to as a CCM frame.

  The frame control unit 12 determines whether or not the ether type value of the received frame is an Ethernet OAM value (S1), and if it is other than the Ethernet OAM value, processes (transmits) it as a user frame (S2). If it is an Ethernet OAM frame, it is determined whether or not the MEG level is higher than its own MEP (S3), and if it is higher than its own MEP, the Ethernet OAM frame is transmitted (S4). If it is an Ethernet OAM frame below the MEG level of its own MEP, it is output to the Ethernet OAM processing unit 15 to determine whether the destination MAC address is a set multicast address or the MAC address of its own port (S5). If the destination address is unknown, it is discarded by the MEP (S6). If it is a multicast address or a MAC address of its own port, the receiving process of the Ethernet OAM frame (shown in detail in FIG. 3) is performed (S7). Here, when the MEG level is the same as the MEG level of the own MEP, reception processing (termination) is performed, and when the MEG level is lower than the MEG level of the own MEP, discarding processing is performed except for the CCM frame.

FIG. 3 shows a processing procedure of the Ethernet OAM processing unit 15.
The Ethernet OAM processing unit 15 identifies a CCM frame, an AIS frame, an LB frame, an LM frame, and a DM frame for the Ethernet OAM frame, and performs processing corresponding to each. If the CCM frame is received (S11), the CC timer is reset and the RDI flag is confirmed (S12, S13). If the RDI flag is not detected, normality is ensured (S14). If the RDI flag is detected, RDI is detected and abnormality detection and alarm processing are performed (S15, S16). On the other hand, the CC timer (S17) is reset by receiving the CCM frame, but when it times out (S18), it detects the LOC and performs abnormality detection and alarm processing (S19, S16).

  If an AIS frame is received (S20), an AIS is detected and abnormality detection and alarm processing are performed (S21, S16). If the LB frame is received (S22), the loopback function process described above is performed (S23), if the LM frame is received (S24), the loss monitor function process is performed (S25), and if the DM frame is received ( S26), the aforementioned delay monitor function processing is performed (S27).

FIG. 4 shows a processing example of the Ethernet OAM frame in the frame control unit 12 of the OSU 10.
When the user frame and the Ethernet OAM frame are input, the frame control unit 12 inserts and outputs the Ethernet OAM frame with priority. That is, the user frame is transmitted after transmitting the Ethernet OAM frame.

The figure which shows embodiment of the Ethernet optical access apparatus of this invention. 5 is a flowchart showing processing procedures of a frame control unit 12 and an Ethernet OAM processing unit 15. 7 is a flowchart showing a processing procedure of the Ethernet OAM processing unit 15. The figure explaining the example of an OAM frame priority process in the frame control part 12. FIG.

Explanation of symbols

10 Optical subscriber line termination unit (OSU)
11 SNI port 12 Frame controller 13 Optical / electrical converter (O / E)
14 OSU Port 15 Ethernet OAM Processing Unit 16 Switching Control Unit 17 Monitoring Control / Alarm Processing Unit 20 Optical Network Termination Unit (ONU)
21 UNI port 22 Frame controller 23 Optical / electrical converter (O / E)
24 ONU Port 25 Ethernet OAM Processing Unit 26 Switching Control Unit 27 Monitoring Control / Alarm Processing Unit 31 Optical Line 32 Upper Node (SW)
33 User terminal

Claims (6)

In an Ethernet optical access apparatus that provides an optical subscriber line termination unit (OSU) and an optical network termination unit (ONU) connected via an optical line as an Ethernet transmission line,
The OSU is configured to pass a user frame, a user Ethernet OAM frame, and a network Ethernet OAM frame, a maintenance function capable of grasping a system state at an Ethernet layer lower than IP, and a plurality of Ethernet transmission paths. An Ethernet optical access apparatus characterized by having a redundant function for setting one of the selected Ethernet transmission paths to be usable. The Ethernet optical access device according to claim 1,
The Ethernet optical access apparatus characterized in that the maintenance function is configured to transmit a periodic communication frame and a communication frame generated as needed and to grasp a state by performing an operation corresponding to the received communication frame. The Ethernet optical access device according to claim 2,
The maintenance function changes the management state of the own device according to the reception fact of the received communication frame, the frame content, and the continuous reception mode associated with the reception of a plurality of communication frames, and transfers the received communication frame, An Ethernet optical access device characterized in that it is configured to discard and generate a new communication frame and control transmission. Ethernet maintenance in which an optical subscriber line termination unit (OSU) and an optical network termination unit (ONU) connected via an optical line are provided as an Ethernet transmission path, and an optical access section is configured redundantly using a maintenance function of the Ethernet layer In the redundancy method,
The OSU is configured to pass a user frame, a user Ethernet OAM frame, and a network Ethernet OAM frame;
Maintenance function steps that can grasp the system status at the lower Ethernet layer than IP,
A redundancy function step of setting one selected Ethernet transmission line to be usable among a plurality of Ethernet transmission lines. The Ethernet maintenance redundancy method according to claim 4,
The Ethernet maintenance redundancy method, wherein the maintenance function step transmits a periodic communication frame and a communication frame that is generated as needed, and grasps a state by performing an operation corresponding to the received communication frame. The Ethernet maintenance redundancy method according to claim 5,
The maintenance function step changes the management state of the own device according to the reception fact of the received communication frame, the frame content, and the continuous reception mode associated with the reception of a plurality of communication frames, and transfers the received communication frame. Ethernet maintenance redundancy method characterized in that new communication frame generation and transmission control are performed by discarding and discarding.

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