KR100887927B1 - Optical network terminal having a self diagnosis - Google Patents

Abstract

The present invention relates to an Ethernet passive optical subscriber network, and more particularly, to an optical network termination device configuring an Ethernet passive optical network having a self-diagnostic recovery function. The optical network termination device of the present invention,

An optical module for outputting a signal detection (SD) signal when the optical signal level input through the optical transmission medium is above a predetermined level; An Ethernet frame processor for outputting a transmission / reception state as a reception (RX) signal and a transmission (TX) signal when an uplink or downlink Ethernet frame is transmitted or received through the optical module; A system recovery processor for determining a system state according to a reception state of a signal detection (SD) signal, a reception (RX) signal, and a transmission (TX) signal, and resetting the system or interrupting the optical module supply power according to the result. By including; to prevent the abnormal data is continuously transmitted by the malfunction of the Ethernet frame processing unit (PON-MAC) and the device control unit (CPU) to ensure a more stable operation, thereby the operation of the entire PON equipment It is effective in preventing paralysis problems in advance.

EPON, ONT, failover.

Description

OPTICAL NETWORK TERMINAL HAVING A SELF DIAGNOSIS}

1 is a schematic diagram of a typical Ethernet Passive Optical Network (EPON).

2 is a view for explaining a discovery handshake message exchange process in a typical EPON.

3 is a diagram illustrating a configuration of an optical network terminator (ONT) according to an embodiment of the present invention.

4 is an exemplary waveform diagram of signals SD, RX, and TX necessary for explaining the operation of the optical network terminator ONT shown in FIG.

5 is a detailed configuration example of the Ethernet frame processing unit shown in FIG.

The present invention relates to an Ethernet passive optical subscriber network, and more particularly, to an optical network termination device configuring an Ethernet passive optical network having a self-diagnostic recovery function.

PON (Passive Optical Network) is an optical subscriber construction method that provides fiber-based high-speed services to companies, SOHO and homes. In particular, the Ethernet passive optical subscriber network (Ethernet-PON: EPON) standardized by the IEEE802 group does not use active devices that use power in the optical subscriber network to improve price competitiveness. It is a network composed of Ethernet technology.

EPON generally uses an optical splitter connected to a network (Optical Line Termination (OLT)) and a plurality of optical network termination devices (Optical Network Termination (ONT)) connected to a subscriber as shown in FIG. It has a structure that is connected manually. In this EPON system, the data transfer between OLT and ONT is transmitted in Ethernet frame, the downstream signal from OLT to ONT is transmitted by broadcasting, and the upsteam signal from ONT to OLT is time division multiplexed access ( The TDMA (TDMA) method is used to share the bandwidth allocated to several ONTs.

For reference, EPON systems can cause data collisions upstream. In order to avoid such a collision, the OLT performs a discovery process as shown in FIG. 2.

Referring to FIG. 2, the OLT transfers a gate message, which is a multi-point control protocol (MPCP) message, to all ONTs. Except for registered ONTs, ONTs that wish to register send a register_request message upstream after a random delay at the start of grant.

On the other hand, the OLT opens a discovery window for a set time and receives a registration request message. The OLT calculates a round trip time (RTT) for each ONT existing at different distances through the registration request message, allocates a logical link identifier (LLID), and transmits a registration message. When the gate message is sent back to the ONT assigned the LLID, the discovery handshake is completed by finally sending the register_ack message to the OLT.

If the description of the method of transmitting and receiving a frame after discovery,

First, in the downstream, the OLT inserts the LLID of the registered ONT into the preamble of the frame, and ONT sends only the frame having its own LLID to the user interface. On the other hand, in the upstream, OLT checks the queue information of each ONU through a report message periodically received from the ONT, and dynamically allocates upstream time slots by granting all ONTs. If ONT sends an MPCP message or user frame at any other time without responding to an OLT's report message request, or not responding to an OLT-allocated time slot, the OLT forces a malformed ONT to guarantee the service of another ONT. Unregister with.

In an EPON network that transmits and receives data using the frame transmission and reception method as described above, if a system component fails in a specific ONT and the laser of the optical module is always turned on, the OLT is defective while one ONT takes over the entire upstream time slot. Because not only ONT but also all ONTs are regarded as not responding correctly, all ONTs are deregistered to block the upward access, which causes the operation of the entire PON device to be paralyzed. In this case, the OLT does not know which ONT is causing the problem. As a result, the operator has to check all ONTs, so the service is delayed and the system maintenance costs are increased.

Accordingly, an object of the present invention is to provide a fiber termination device that can self-diagnose the failure or failure state of the system components so that the operation of the entire EPON network equipment is not paralyzed together.

Furthermore, it provides a fiber termination device that constitutes an EPON network that can normally restore the equipment itself without a visitor in the event of a equipment problem.

An optical network termination device constituting an Ethernet passive optical subscriber network (EPON) according to an embodiment of the present invention for achieving the above object,

An optical module for outputting a signal detection (SD) signal when the optical signal level input through the optical transmission medium is above a predetermined level;

An Ethernet frame processor for outputting a transmission / reception state as a reception (RX) signal and a transmission (TX) signal when an uplink or downlink Ethernet frame is transmitted or received through the optical module;

A system recovery processor for determining a system state according to a reception state of a signal detection (SD) signal, a reception (RX) signal, and a transmission (TX) signal, and resetting the system or interrupting the optical module supply power according to the result. Characterized by including;

The system recovery processing unit resets the Ethernet frame processing unit if the reception (RX) signal and the transmission (TX) signal are not received during the first set time T1 after the signal detection (SD) signal is received.

Further, the system recovery processing unit,

The device controller may be reset when the watchdog control signal is not received during the second preset time T2 after the signal detection SD signal is received.

In addition, when the transmission (TX) signal is received for more than a third predetermined time, the system recovery processing unit cuts off the optical module power supply, characterized in that for resetting the Ethernet frame processing unit,

In some cases, if there is no reception of the RX signal within the fourth set time T4 after receiving the TX signal, the optical module supply power is cut off, even if the signal is repeated a predetermined number of times. If there is no reception of the optical module is characterized in that the power supply cut off.

According to the configuration as described above, the optical network termination device of the present invention does not receive a message from the optical line terminal (OLT) for a predetermined time after the message transmission, or there is no response for a predetermined time after receiving the message, or continue for a predetermined time or more If the message is being sent, it is determined that the system component is defective or faulty, and the equipment is initialized by shutting off the optical module supply power or resetting the corresponding system component.

Therefore, a problem that may be caused by a single failed fiber terminal device, that is, the operation of the entire network equipment is prevented from being paralyzed in advance, or the equipment itself may be restarted to obtain an effect of normal recovery.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, a detailed description of related known functions or configurations will be omitted.

First, FIG. 3 illustrates a configuration diagram of an optical network terminator (ONT) according to an embodiment of the present invention, Figure 4 is a signal SD, necessary to explain the operation of the optical network terminator (ONT) shown in FIG. RX and TX are waveform diagrams, and FIG. 5 is a detailed configuration diagram of the Ethernet frame processor 120 shown in FIG. 3, respectively.

Referring to FIG. 3, first, the optical module 110 performs photoelectric conversion on the packet data input through the optical transmission medium or performs all-optical conversion for output to the optical transmission medium. The optical module 110 supports the output of a Loss of Signal or Signal Detect (SD) signal, and is typically a transmitter power pin (VeeT) and a receiver power pin (VeeR). ) Are separated.

For reference, the signal loss signal LOS is activated in a “high” state as shown in FIG. 4 when the optical input signal falls below a predetermined reception level, and the signal detection signal SD is in contrast to the optical input signal. When the signal rises above a predetermined reception level, the signal is activated in a "high" state as shown in FIG.

Meanwhile, when the uplink or downlink Ethernet frame (MPCP, OAM, data, etc.) is transmitted or received through the optical module 110, the Ethernet frame processing unit 120 receives a transmission (RX) signal and a transmission (TX) signal, respectively. And print it out. The Ethernet frame processing unit 120 is usually implemented as a one-chip IC, also referred to as PON-MAC. The Ethernet frame processor 120 includes functional blocks as shown in FIG. 5.

Referring to FIG. 5, the SerDes 121, which is one component of the Ethernet frame processing unit 120, converts parallel data into serial data that the optical module 110 can transmit in the optical network terminator 100 and performs reverse conversion thereof. In addition, the MPCP (Media Point Control Protocol) MAC (Media Access Control) MAC 125 supports 802.3ah, the EPON standard, and supports point-to-point and point-to-multipoint operation. It also adds its own LLID to the transport packet and removes the LLID from the received packet. The MPCP MAC 125 outputs the state through the TX or RX terminal when there is an Ethernet frame transmission and reception. The optical module controller 123 generates and outputs an optical module control signal (burst) to transmit data when the time is allocated to the optical network terminator 100 itself, and the GMAC is an external device (CPU, switch). It supports GMII / MII connection to 10/100 devices as well as GbE.

Referring back to FIG. 3, the system recovery processor 130 may include a signal detection (SD) signal output from the optical module 110, a reception (RX) signal and a transmission (TX) signal output from the Ethernet frame processing unit 120. The system state is determined according to the reception state, and according to the result, the system (Ethernet frame or device control unit) is reset or the power supply to the optical module 110 is interrupted.

For example, when the signal detection (SD) signal is received from the optical module 110, the system recovery processor 130 may receive the RX signal from the Ethernet frame processor 120 during the first preset time T1. Check if the TX signal is received. As a result of the check, if there is no reception of the RX signal and the TX signal, the Ethernet frame processing unit 120 is in an abnormal state and outputs a reset signal for resetting the Ethernet frame processing unit 120.

Finally, the device controller (CPU) 140 plays a role of comprehensively managing and controlling the optical network termination device 100.

Hereinafter, the operation of the optical network termination device 100 having the above-described configuration will be described in more detail.

First, when the signal detection (SD) signal is received from the optical module 110, the system recovery processor 130 of the optical network terminal device 100 that exchanges data with the optical line terminal device OLT is set in advance. During the time T1, it is checked whether the reception (RX) signal and the transmission (TX) signal are received from the Ethernet frame processing unit 120. As a result of the check, if there is no reception of the RX signal and the TX signal, this indicates that the Ethernet frame processing unit 120 is in an abnormal state and is reset by initializing the Ethernet frame processing unit 120. When the Ethernet frame processing unit 120 is normally restored by this operation, data is normally exchanged with the optical line terminal device (OLT), but if it is not normally restored, the above operation is repeated again.

Further, the system recovery processor 130 is abnormal when the watchdog control signal is not received during the second set time T2 after the signal detection (SD) signal is received from the optical module 110. The system controller 140 resets the device controller 140 to restore the system to normal operation.

As described above, in the present invention, if there is no reception of the transmission signal TX or the watchdog control signal for a predetermined time after the signal detection (SD) signal is received from the optical module 110, the present invention determines that the component is a failure of the system component. By resetting, more stable operation can be ensured.

Further, the system recovery processing unit 130 checks whether the transmission (TX) signal is received from the Ethernet frame processing unit 120 for more than a third predetermined time T3. If the transmission (TX) signal is continuously received from the Ethernet frame processing unit 120, since the Ethernet frame processing unit 120 operates abnormally, the system recovery processing unit 130 supplies power to the optical module 100. Block and reset the Ethernet frame processing unit 120 to restore the system to normal.

Further, the system recovery processing unit 130 may not communicate with the optical line terminal device OLT if the reception (RX) signal is not received within the fourth set time T4 after the transmission (TX) signal is received from the Ethernet frame processing unit 120. When it is determined that a problem has occurred, the power supply for the optical module 110 is temporarily cut off. If the reception (RX) signal is not received even after repeating the predetermined number of times, the power supply for the optical module 110 is finally cut off. For reference, the system recovery processor 130 may supply power to the optical module 110 after the fifth set time (T5:> T4) has elapsed.

According to the operation as described above, if a message is not received from the optical line terminal device (OLT) for a predetermined time after receiving the TX signal, the power of the transmitting end of the optical module 110 is forcibly cut off, so that the defective optical module or It is possible to prevent problems caused by the laser driver, that is, paralyzing the operation of the entire PON device together.

As described above, the present invention forcibly cuts off the power supply of the optical module when a message is not received from the optical line terminal device (OLT) for a predetermined time after the message is transmitted. That is, there is an advantage that can solve the problem of the operation of the entire PON equipment paralyzed.

Furthermore, the present invention monitors the states of the Ethernet frame processing unit PON-MAC and the device control unit CPU to cut off the power supply to the optical module, and resets the Ethernet frame processing unit PON-MAC and the device control unit CPU. It prevents the abnormal data from being transmitted continuously due to malfunction of Ethernet frame processing unit (PON-MAC) and device control unit (CPU) to ensure more stable operation. There is an effect that can be blocked.

In addition, the present invention has the advantage that even if a failure occurs in one optical fiber termination device because the remaining optical network termination devices can be serviced normally.

In addition, since the fiber termination device can self-diagnose and restore the performance of each element of the system, the side effect of reducing the recovery time and the operating cost of the equipment can be obtained.

On the other hand, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only by the appended claims.

Claims (7)

An optical module for outputting a signal detection (SD) signal when the optical signal level input through the optical transmission medium is above a predetermined level; An Ethernet frame processor for outputting a transmission / reception state as a reception (RX) signal and a transmission (TX) signal when an uplink or downlink Ethernet frame is transmitted or received through the optical module; A system recovery processor for determining a system state according to a reception state of a signal detection (SD) signal, a reception (RX) signal, and a transmission (TX) signal, and resetting the system or interrupting the optical module supply power according to the result. Optical network termination device comprising a. The method of claim 1, wherein the system recovery processing unit, And resetting the Ethernet frame processor if the reception (RX) signal and the transmission (TX) signal are not received during the first set time T1 after the signal detection (SD) signal is received. The system recovery processing unit according to claim 1 or 2, And a device control unit is reset when no watchdog control signal is received for a second predetermined time (T2) after the signal detection (SD) signal is received. The system recovery processing unit according to claim 1 or 2, When the transmission (TX) signal is received for more than a third predetermined time, the optical network termination device characterized in that the power supply to the optical module and reset the Ethernet frame processing unit. The method of claim 4, wherein the system recovery processing unit, And a device control unit is reset when no watchdog control signal is received for a second predetermined time (T2) after the signal detection (SD) signal is received. The method of claim 5, wherein the system recovery processing unit, If the reception (RX) signal is not received within the fourth set time T4 after the transmission (TX) signal is received, the optical module supply power is temporarily cut off, and the reception of the reception (RX) signal is repeated even if the signal is repeated a predetermined number of times. If not, the optical network termination device, characterized in that to completely cut off the optical module supply power. The optical network terminator of claim 6, wherein the system recovery processor supplies power to the optical module after a fifth set time (T5:> T4).

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