KR20040057868A - Passive optical network system having a function of protecting and recovering network and method for protecting and recovering network in the system - Google Patents

Abstract

PURPOSE: A network protecting/recovering method in a PON(Passive Optical Network) system is provided to enable an optical network device to transmit registration request messages to an ONU(Optical Network Unit) as responses to the first and second gate messages, so that an OLT(Optical Line Terminal) and the ONU can sense an MPCP(Multi-Point-Control Protocol) message state to perform a proper protection/ recovery function. CONSTITUTION: An OLT confirms whether a report signal is received from ONUs(S200). If not(S202), the OLT sets a recovery path by using an optical switch(S204), and transmits a gate message to the ONUs(S206). If a register request message is received from the ONUs(S208), the OLT transmits a register message to the ONUs(S210). The OLT performs a raging process(S212), and transmits a gate message to the ONUs(S214). If a register acknowledgement message is received from the ONUs(S216), the OLT completes the raging process. If a response to the gate message is not received from the ONUs(S208), the OLT informs an operator of a splitter failure(S218). If a signal is not received from a specific ONU by a partial SF(Signal Failure)(S202), the OLT informs the operator of the failure(S220).

Description

Passive optical network system having a function of protecting and recovering network and method for protecting and recovering network in the system

The present invention relates to a passive optical subscriber system having a network protection recovery function and a network protection recovery method in the system. More specifically, the MAC protocol is used in a structure in which only a trunk portion between the optical termination device and the splitter is duplicated. The present invention relates to a system and a method for performing protection recovery of a passive optical subscriber network.

Along with the rapid increase of the Internet use population, various application services based on the Internet have emerged, which demands an increase in the required bandwidth and quality improvement. This trend is not limited to business subscribers, but extends to residential subscribers and needs to provide the desired bandwidth inexpensively to where the end user is. Accordingly, the optical transmission technology used only in the existing backbone network is expanding to the subscriber network.

Next-generation optical subscriber transmission technologies expected to meet these requirements include: Very High Data Rate Digital Subscriber Line (VDSL), Passive Optical Network (PON), Metro Ethernet, and Multi-Service Provisioning Platform Technology). The PON is a passive optical network that provides connectivity in the form of FTTx to subscribers within a 20 km radius. PON is inexpensive because it can be used to connect up to 64 Optical Network Unit / Optical Network Termination (ONU / ONT) at the same time by branching into multiple strands through one optical splitter. This means that the PON can be connected and operated simultaneously on one platform, such as FTTCab, FTTC, FTTB, and FTTH. Therefore, PON integrates FTTx in one platform to support FTTH, which is the ultimate subscriber network form, which is important as next generation optical subscriber transmission technology.

In the ITU-T standard, G.983.1, four PON protective recovery schemes are mentioned. <Type A> is a cost-effective structure that duplicates only the trunk portion between the OLT (Optical Line Terminal) and the splitter. <Type B> is a structure in which trunk and OLT line card are duplicated, and <Type C> is a structure in which ODN is duplicated. In the case of <Type B>, it has the advantage of increasing the price / performance ratio by dualizing only the common parts. However, an ONU with various needs cannot be accommodated in a single PON. On the other hand, in the case of <Type C>, 100% protection is possible by redundancy of all parts, but it has a disadvantage of high installation cost of PON. <D Type> is a structure that is able to protect and recover in case of problems in two lines (branch or trunk) by duplexing the whole ODN and adding splitter inside. <Type D> provides strong protection and recovery, but has the disadvantage of high installation cost and complicated structure.

The technical problem to be achieved by the present invention is to recover the protection using EPON MPCP messages (GATE, REPORT, REGISTER_REQ, REGISTER, REGISTER_ACK) in the <type A> structure, which is the most economical among the other four PON protection recovery structures. It is to provide a passive optical subscriber network protection and recovery system and method capable of performing the function.

1 is a view showing the structure of a PON to which the present invention is applied;

2 is a flowchart illustrating a process of performing an OLT protection recovery method according to the present invention, and

3 is a flowchart illustrating a process of performing an ONU protection recovery method according to the present invention.

In order to achieve the above technical problem, a plurality of optical network devices according to the present invention are connected to an optical termination device through a splitter, and a plurality of trunks are installed between the plurality of optical network devices and the splitter. In the passive optical subscriber system having a function, when the optical termination device fails to receive a report message from the optical network device, the optical termination device sets a recovery path via one trunk among the plurality of trunks using an optical switch, and then The first gate message is transmitted to the optical network device, when the registration request message is received from the optical network device, the registration message is transmitted, the second gate message is transmitted to the optical network device after the lasing is performed. And the optical network device ends the optical termination in response to the first gate message. A registration request message in response to the second gate message, and a registration request message in response to the second gate message.

In order to achieve the above technical problem, a plurality of optical network devices according to the present invention are connected to an optical termination device through a splitter, and a plurality of trunks are provided between the plurality of optical network devices and the splitter. Network protection recovery method in a subscriber system, the method comprising the steps of: (a) transmitting a first gate message to the optical network device; (b) checking whether a report message including status information is received from the optical network device; And (c) if the report message is received within a predetermined time, transmitting a second gate message to the optical network device to permit data transmission, and performing a recovery process if the report message fails to be received. The recovery process may include: (d) setting a recovery path via one trunk of the plurality of trunks using an optical switch; (e) transmitting a first gate message to the optical network device through the set recovery path; (f) if the registration request message is received from the optical network device, transmitting the registration message, performing a raging, and transmitting a second gate message to the optical network device.

According to the present invention, it is possible to perform a simple and economical protection recovery function in 50ms by providing a basic protection recovery function by using a part commonly used by all ONUs and using <Type A> having excellent price / performance ratio.

The present invention uses the EPON protection recovery structure using the EPON MPCP message in <Type A>, which is a PON structure in which the trunk portion between OLT and ONU, which are commonly used by all ONUs, is duplicated, and proposes a protection recovery method. It is for.

There are five MPCP messages: GATE, REPORT, REGISTER_REQ, REGISTER, and REGISTER_ACK. These are Ethernet MAC control frames that follow the format defined by the IEEE 802.3 ah group.

The OLT authorizes transmission by sending a GATE message to the ONU, and the ONU transmits data at the authorized time through the information in the GATE message. At this time, the ONU transmits the status information in its own waiting queue to the OLT using the REPORT message, so that the ULT can inform the OLT of the bandwidth required for the next transmission. ONU can send data to OLT after receiving GATE message from OLT. OLT can send next GATE message after receiving REPORT message from ONU.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of a passive optical subscriber network protection recovery method using a MAC protocol according to the present invention.

FIG. 1 is a diagram showing an economical structure of a PON (G.983.1 Type A).

Referring to FIG. 1, the PON 100 includes a plurality of ONUs 110 and 120, a splitter 130, and an OLT 140. Each ONU 110, 120 has a line card 115, 125 and is connected to the splitter 130 via optical paths 150, 160 connected to the line cards 115, 125. Between the splitter 130 and the OLT 140, a main light path 170 and an auxiliary light path 180 are constructed. The OLT 140 is also connected to the splitter 130 through the line card 145. In this manner, by hardware redundancy of the line between the splitter 130 and the OLT 140, which are commonly used parts, the protection recovery function can be added to all ONUs 110 and 120. FIG.

2 is a flowchart illustrating a process of performing an OLT protection recovery method according to the present invention.

Referring to FIG. 2, the OLT 140 checks whether a report is received from the ONUs 110 and 120 (S200). If a signal failure (SF) occurs, the OLT 140 may not receive a report from the ONUs 110 and 120. If the OLT 140 does not receive the REPORT signal by the SF of the entire signal (S202), the path to the recovery path is set by using the optical switch in the protection line card (S204), and the ONU (110, 120) The GATE message is transmitted (S206). When receiving the REGISTER_REQ message in response to the GATE message from the ONU (110, 120) (S208), OLT 140 transmits a REGISTER message to the ONU (110, 120) (S210). In addition, the OLT 140 transmits a GATE message to the ONUs 110 and 120 after performing Raging (S212) (S214). When receiving the REGISTER_ACK message in response to the GATE message from the ONU (110, 120) (S216), OLT 140 terminates Ranging. If a response to the GATE message is not received from the ONUs 110 and 120 (208), the OLT 140 determines that the splitter has failed and notifies the operator (218). On the contrary, if the signal is not received from the specific ONUs 110 and 120 by the partial SF (S202), the OLT 140 determines that the branch is broken and notifies the operator (S220).

On the other hand, if the OLT 140 receives the REPORT from the ONU (110, 120) (S200), it checks whether the received signal is normal (S222). The abnormal signal is generated by Signal Degradation (SD) or an error, and when an abnormal signal occurs, it can be classified into the following four types.

Case a: Received REPORT with SD from all ONUs;

Case b: when an SD generated REPORT is received from one ONU;

Case c: when faulty data is received from all ONUs;

Case d: when faulty data is received from one ONU;

If confirmed as Case a (S224), OLT 140 retransmits the GATE message to all ONU (110, 120) (S226) and confirms the occurrence of Case a (S228). If Case a occurs again, go to Step A.

If the case b is confirmed (S230), the OLT 140 retransmits the GATE message to the corresponding ONU (110 or 120) (S232) and confirms the occurrence of Case b (S234). If Case b occurs again, OLT 140 determines that the branch has failed and notifies the operator (236).

If the case c is confirmed (S238), the OLT 140 detects the SD (S240) and retransmits the GATE message to all ONUs (110, 120) (S242) and checks the occurrence of Case c (S244). If Case c occurs again, go to Step A.

If it is confirmed as the case d (S246), the OLT 140 detects the SD (S248) and retransmits the GATE message to the corresponding ONU (110 or 120) (S250) and confirms the occurrence of Case d (S252). If Case d occurs again, the OLT 140 determines that the branch has failed and notifies the operator (S254).

3 is a flowchart illustrating a process of performing an ONU protection recovery method according to the present invention.

Referring to FIG. 3, the ONUs 110 and 120 check whether a GATE message has been received (S300). If the ONU (110, 120) does not receive a GATE message from the OLT 140, it determines that the signal is not received by the SF (S305). In this case, the ONUs 110 and 120 stop transmission of the report to the OLT 140 (S310). If the ONU (110, 120) does not receive a GATE message from the OLT 140 within a certain time (S315), and transmits a REGISTER_REQ message to the OLT (140) (S320). When receiving a REGISER message from the OLT 140 (S325), the ONU (110, 120) performs Ranging (S330). When the GATE message is received from the OLT 140 (S335), the ONUs 110 and 120 transmit a REGISTER_ACK message to the OLT 140 (S340). On the contrary, if a GATE message is not received from the OLT 140 even after a predetermined time has elapsed (S315), the ONUs 110 and 120 determine that the branch or the splitter has failed and notify the operator (S345).

On the other hand, if the ONU (110, 120) receives a GATE message from the OLT (140) (S300), it checks whether the received signal is normal (S350). Abnormal signals are caused by signal degradation (SD) or an error, and when an abnormal signal occurs, it can be classified into the following two types.

Case e: Received a report in which SD occurred from the OLT 140;

Case f: when data including an error is received from the OLT 140;

When the ONUs 110 and 120 receive a GATE message in which SD is generated from the OLT 140 (S355), the ONUs 110 and 120 request retransmission of the signal to the OLT 140 (S360). 120) Check whether the case e occurs (S365). If Case e occurs again, go to Step B.

When the ONUs 110 and 120 receive data containing an error from the OLT 140 (S370), the ONUs 110 and 120 detect the SD (375) and request retransmission of the signal to the OLT 140 ( S380). The ONUs 110 and 120 check whether Case f is generated (S365). If Case f occurs again, the ONUs 110 and 120 determine that the branch is broken and notify the operator (S385).

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer device is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer devices so that the computer readable code is stored and executed in a distributed fashion.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific preferred embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

According to the passive optical subscriber system having a network protection recovery function according to the present invention and a network protection recovery method therefor, the system provides a basic protection recovery function by providing a dual protection of all ONUs and provides excellent cost performance. By using <Type A>, a simple and economical protection recovery function can be performed within 50ms.

Claims (10)

In a passive optical subscriber system having a network protection recovery function in which a plurality of optical network devices are connected to an optical termination device through a splitter, and a plurality of trunks are provided between the plurality of optical network devices and the splitter. If the optical termination device fails to receive a report message from the optical network device, the optical termination device sets a recovery path via one trunk among the plurality of trunks using an optical switch, and then transmits a first gate message to the optical network device. When the registration request message is received from the optical network device, the registration message is transmitted, the second gate message is transmitted to the optical network device after the raging. The optical network device transmits a registration request message to the optical termination device in response to the first gate message, and transmits a registration request message in response to the second gate message. Passive optical subscriber system provided. The method of claim 1, When the report message received from the optical network device is determined to be an abnormal signal, the optical terminator determines the type of error that occurred in the report message, and when the error that occurs in the report message is identified as error type 1 or error type 2, The second gate message is transmitted to the optical network device, and if the error type 3 or the error type 4 is detected, the second gate message is transmitted to the optical network device that has transmitted a report message in which deep signal attenuation occurs or an error exists. Check if the error occurs again, The passive type optical subscriber system with a network protection recovery function is defined as follows. Error form 1: Receive report message from signal loss from all optical network devices; Error type 2: Receive report signal message with error from all optical network devices; Error type 3: Receive report message of signal loss from one optical network device; Error type 4: Receive report of error from one optical network device. The method of claim 2, When the error type 1 or the error type 3 reoccurs, the optical termination device sets the recovery path and transmits the first gate message to the optical network device, and registers when a registration request message is received from the optical network device. Send a message, perform a raging, and transmit a second gate message to the optical network device; And if the error type 2 or the error type 4 reoccurs, determining that the branch of the optical network device which has transmitted the report message in which the signal attenuation has occurred is a failure. The method of claim 1, When the optical network device fails to receive the first gate message from the optical termination device, the optical network device stops transmitting the report message. If the optical network device fails to receive the first gate message within a predetermined time, the registration request is sent to the optical termination device. And transmitting the message and performing the lasing upon receiving the registration message in response to the registration request message from the optical termination device. The method of claim 4, wherein And the optical network device determines that a failure of a branch or the splitter occurs if the reception of the first gate message fails after the predetermined time has elapsed. The method of claim 1, When the first gate message received from the optical termination device is determined to be an abnormal message, the optical network apparatus determines an error type of the first gate message, and when an error occurring in the first gate message is determined as an error type 1 Request retransmission of the first gate message to the optical termination device, and if it is determined that the error type 2 is detected, after detecting the deep decay of the received first gate message, request the retransmission of the first gate message to the optical termination device , The passive type optical subscriber system with a network protection recovery function is defined as follows. Error Form 1: Receive first gate message from which signal attenuation occurs; Error type 2: Receive first gate message with an error from the optical termination device. The method of claim 6, The optical network device stops the transmission of the report message to the optical termination device when the error type 1 or the error type 2 reoccurs, and when the first gate message is successfully received from the optical termination device, the optical termination When the registration request message is transmitted to the device and the registration message is received from the optical termination device in response to the registration request message, lasing is performed. If the reception of the first gate message from the optical termination device fails, Passive optical subscriber system having a network protection recovery function, characterized in that judged to be a failure. In the network protection recovery method of a passive optical subscriber system in which a plurality of optical network devices are connected to an optical termination device through a splitter, and a plurality of trunks are provided between the plurality of optical network devices and the splitter. (a) transmitting a first gate message to the optical network device; (b) checking whether a report message including status information is received from the optical network device; And (c) if the report message is received within a predetermined time, transmitting a second gate message to the optical network device to allow data transmission, and performing a recovery process if the report message fails to be received. The recovery process, (d) setting a recovery path via one trunk of the plurality of trunks using an optical switch; (e) transmitting a first gate message to the optical network device through the set recovery path; (f) if the registration request message is received from the optical network device, transmitting the registration message, performing a raging, and transmitting a second gate message to the optical network device. Protective recovery method. The method of claim 8, Step (c) is, (c1) checking whether the report message received from the optical network device is normal; (c2) if the report message is determined to be an abnormal signal, identifying a type of error occurring in the report message; And (c3) If the error occurring in the report message is identified as error type 1 or error type 2, the second gate message is transmitted to all the optical network devices. If the error message is identified as error type 3 or error type 4, deep block attenuation occurs or an error is detected. And confirming whether the error reoccurs after transmitting the second gate message to the optical network apparatus that has transmitted the existing report message. The type of error is a network protection recovery method characterized in that: Error form 1: Receive report message from signal loss from all optical network devices; Error type 2: Receive report signal message with error from all optical network devices; Error type 3: Receive report message of signal loss from one optical network device; Error type 4: Receive report of error from one optical network device. The method of claim 9, Step (c) performs the recovery process when the error type 1 or the error type 3 reoccurs, and transmits a report message in which the signal attenuation occurs when the error type 2 or the error type 4 reoccurs. Network protection recovery method further comprising the step of determining that the branch of the failure.