KR100653188B1 - Ethernet link duplication apparatus and its protection switching method and receiver according to the same - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an Ethernet link redundancy system, a switching control method thereof, and a receiver accordingly.

2. The technical problem to be solved by the invention

According to the present invention, a dedicated spare link is provided for one operation link in a Gigabit Ethernet (xGbE) connected to a point-to-point, and when an operation link failure occurs, it is detected and transferred to the spare link. In order to provide protection switching, such as in SDH (Synchronous Digital Hierarchy) / SONET (Synchronous Optical NETwork), an Ethernet link redundancy system and its switching control method and a receiving device are provided.

3. Summary of Solution to Invention

The present invention, in the Ethernet link redundancy system, having a dedicated spare link for one operation link connected between the transmission and reception nodes for transmitting and receiving Ethernet signals, the operation link and the spare link in the transmission Physical Media Dependant (PMD) layer Transmission means for transmitting an Ethernet signal through the operation link and the spare link by bridging the signal; And receiving means for switching from a receiving PMD layer to a link in a normal state of the operational link or the spare link and receiving the Ethernet signal on the link according to a coding error detected in the decoding process.

4. Important uses of the invention

The invention is used in Gigabit Ethernet systems and the like.

Ethernet, protection switching, redundancy, operation link, spare link

Description

Ethernet link duplication apparatus and its protection switching method and receiver according to the same

1 is an exemplary configuration diagram of an Ethernet link redundancy system in a normal linear network according to the present invention;

2 is an exemplary configuration diagram of an Ethernet link redundancy system in an abnormal (failure) linear network according to the present invention;

3 is a configuration diagram of an embodiment of an Ethernet link redundancy system according to the present invention;

4 is a detailed flowchart illustrating an embodiment of a transfer request signal processing procedure in a transfer control method of an Ethernet link redundancy system according to the present invention;

FIG. 5 is a detailed flowchart illustrating an embodiment of a switchover process in a switchover control method of an Ethernet link redundancy system according to the present invention.

* Explanation of symbols for the main parts of the drawings

200: transmission unit 200A, 210A: operation unit

200B, 210B: spare part 201: operating part optical transmitter

202: spare part optical transmitter 203, 213: operating part converter

204, 214: spare converter 205, 216: signal converter

206, 217: PMA 207, 219: PCS

208, 220: GBIC interface 210: receiver

211: operation unit optical receiver 212: spare unit optical receiver

215: selector 218: controller

The present invention relates to an Ethernet link redundancy system, a switching control method thereof, and a receiving device according to the present invention, and more particularly, to perform protection switching on a failing line in the event of a failure or performance degradation in an Ethernet link by duplexing a Gigabit Ethernet system. The present invention relates to an Ethernet link redundancy system, a switching control method thereof, and a receiving device according to the same.

Protection switching technology has been widely applied in optical transmission equipment, such as PDH (Plesiochronous Digital Hierarchy), SDH (Synchronous Digital Hierarchy) / SONET (Synchronous Optical NETwork). Also, in SDH / SONET, annular networks with self-healing functions such as UPSR (Undirectional Path Switched Ring) and BLSR (Bidirectional Line Switched Ring) as well as point-to-point linear protection switching technologies such as 1 + 1 and 1: N There is also protection switching technology.

However, in Ethernet, there is no technology to perform protection switching at the physical layer, and only the MAC frame can be received through a different path at the MAC (Media Access Control) layer.

Therefore, in the existing Ethernet protection switching technology, when the Ethernet link fails or the performance decreases, the availability of the link decreases due to the failure, and the quality of the MAC signal transmitted through the link cannot be guaranteed. The reason for this is that when a failure occurs, rapid protection switching is not performed for the failure zone, and the topology is established because time is consumed to construct a new topology in the remaining zones except for the failure zone by the STP (Spanning Tree Protocol). This is because it is not serviced during construction.

In other words, the existing Ethernet system requires a lot of recovery time because the Ethernet signal is recovered through the bypass path by the Spanning Tree Protocol (STP), which reduces the availability of the Ethernet network and prevents quality service. There is a problem.

The present invention has been proposed in order to solve the above problems, by providing a dedicated spare link for one operation link in the Gigabit Ethernet (xGbE: x = 1,10) connected to point-to-point operation link failure It is an object of the present invention to provide an Ethernet link redundancy system, a switching control method thereof, and a reception device according to the present invention, by detecting and detecting a changeover to a spare link to enable protection switching as in SDH / SONET.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

A system of the present invention for achieving the above object, in an Ethernet link redundancy system, having a dedicated spare link for one operation link connected between a transmitting and receiving node for transmitting and receiving an Ethernet signal, a transmission physical media dependant (PMD) layer Transmitting means for bridging the operational link and the spare link to transmit Ethernet signals through the operational link and the spare link, respectively; And receiving means for switching from a receiving PMD layer to a link in a normal state of the operational link or the spare link and receiving the Ethernet signal on the corresponding link according to a coding error detected in the decoding process.

On the other hand, the method of the present invention, in the switching control method of the Ethernet link redundancy system, having a dedicated spare link for one operation link connected between the transmission and reception nodes for transmitting and receiving Ethernet signals, and the operation link in the transmission PMD layer Bridging the spare link; A failure detection step of detecting, by the receiving node, a failure of the operation link based on a coding error detected by decoding an Ethernet signal received from the transmitting node; And switching the receiving node from the receiving PMD layer to the spare link when a failure of the operation link is detected.

In addition, the method of the present invention further includes the step of checking whether the operational link is normal, and returning to the operational link as set to the normal and returnable transfer mode.

On the other hand, the apparatus of the present invention, Ethernet link redundancy receiving apparatus, comprising: operational receiving means for receiving and converting an Ethernet signal through an operational link; Preliminary receiving means for receiving and converting an Ethernet signal through a preliminary link provided exclusively for the operation link; Interfacing means for interfacing received signals from said operational receiving means and said preliminary receiving means; Signal selection means for selecting a reception signal from the operational reception means or the preliminary reception means received through the interfacing means according to a control signal of a control means; Signal conversion means for converting the received signal from the signal selection means; A physical medium attachment (PMA) for restoring data and converting the data into parallel data using a clock extracted from the received signal from the signal converting means; A physical coding sublayer (PCS) for decoding a parallel signal from the PMA into a MAC signal to detect a coding error; And the control means for receiving switching error information from the PCS and performing switching control.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exemplary configuration diagram of an Ethernet link redundancy system in a normal linear network according to the present invention, in which 1 + 1 linear protection switching is performed in a normal operation state between node 1 (transmitter) 101 and node 2 (receiver) 102. It shows the operation process.

As shown in FIG. 1, a media access control (MAC) signal consisting of 8 bits in Gigabit Ethernet is encoded into an 8B / 10B signal in a physical coding sublayer (PCS) layer and converted into a 10 bit signal.

Subsequently, the changed 10-bit signal is changed into a non-return to zero (NRZ) signal serialized by a SerDes (Serialize and Deserize) function at the physical medium attachment (PMA) layer 110 of the node 1 (101). The electrical signal is converted into an optical signal by the physical media dependent (PMD) 111 and transmitted to the node 2 (receive end node) 102.

Subsequently, when the optical signal is converted back into an electrical signal by the PMD 115 and transmitted to the PMA 117, the node 2 102 detects a preamble signal indicating the start of the Ethernet signal by the PMA 117 to transmit a signal. Synchronize the received signal for.

The synchronized signals are made by using SerDes, and the parallelized 10bit signals are made and transferred to the PCS layer. Then, the 8B / 10B signals are decoded to restore the 8bit MAC signal.

Therefore, in FIG. 1, when the PMD 111, the optical path 113, and the PMD 115 constituting the operation link are normal, the transmission PMD 111 signal is finally transmitted through the PMA 117 through the operation link. Will be output. In addition, the signal is received through the PMD 112, the optical path 114, and the receiving PMD 116 constituting the preliminary link, but the signal is not received by the PMA 117.

2 is an exemplary configuration diagram of an Ethernet link redundancy system in an abnormal (failure) linear network according to the present invention.

As shown in FIG. 2, in an abnormal (failure) linear network according to the present invention, the Ethernet link redundancy system includes a failure 120 in the PMD 111, the optical path 113, and the PMD 115 constituting the operational link. In this case, the reception PMA 117 receives and outputs a signal from the spare link PMD 116 rather than receiving a signal from the PMD 115 of the operation link.

In addition, while receiving traffic from the spare link in reverse, if a failure occurs in the spare link, it is returned to the operation link again. In this case, however, there is no failure in the operational link.

3 is a configuration diagram of an embodiment of an Ethernet link redundancy system according to the present invention.

As shown in FIG. 3, the Ethernet link redundancy system according to the present invention has a dedicated spare link for one operation link connected between a transmitting and receiving node for transmitting and receiving an Ethernet signal, and the operating link in the transmitting PMD layer. Transmitter 200 for bridging the spare link to transmit Ethernet signals through the operational link and the spare link, respectively, and in accordance with the coding error detected in the decoding process, the operation link or the spare link in the receiving PMD layer. It includes a receiver 210 for switching to a link in a normal state and receiving the Ethernet signal on the link.

Here, the transmitter 200 allows the 8-bit MAC signal transmitted from the GMII (Gigabit Media Independent Interface) to be encoded by the PCS 207 into a 10-bit 8B / 10B signal.

The encoded 8B / 10B signal is then converted by the PMA 206 into serial data in the form of NRZ, followed by a bipolar signal by the signal converter 205 for the Giga Bit Interface Convert (GBIC) interface 208. Is converted to. The converted bipolar signal is branched through the signal converter 205 to drive the operating unit 200A and the spare unit 200B.

Subsequently, the signals branched to the operating unit 200A and the spare unit 200B are operated by the operating unit converter 203 and the spare unit converter 204 to drive the operating unit optical transmitter 201 and the spare unit optical transmitter 202, respectively. Is converted into a unipolar signal.

Accordingly, the Ethernet signal converted into a monopolar signal is converted into an optical signal by the operating unit optical transmitter 201 and the spare unit optical transmitter 202 and transmitted respectively. By doing so, the transmitting unit 200 may always transmit the same signal through the operating unit 200A and the reserve unit 200B, and a failure occurs in the operating unit 200A or the reserve unit 200B and requires repair. In this case, only the optical transceiver with GBIC interface function should be replaced to ensure normal operation.

Meanwhile, the receiver 210 converts an optical signal transmitted from the outside into an electrical signal through the operation unit optical receiver 211 and the preliminary unit optical receiver 212 provided in the operation unit 210A and the reserve unit 210B. do.

Then, the electrically converted signal is converted into a bipolar signal by the operating unit converter 213 and the spare unit converter 214 for the GBIC interface 220, and the Ethernet signal and the spare unit received by the operating unit 210A ( Selector 215 is driven by controller 218 to select the Ethernet signal received at 210B so that one of the two signals is selected. The selected Ethernet signal is converted into a unipolar signal by the signal converter 216 and input to the PMA 217. Then, the PMA 217 extracts a clock and data to extract the received Ethernet frame, detects a preamble indicating the start of the Ethernet frame, and synchronizes the received frame. The synchronized signal is transmitted to the PCS 219 in units of 10 bits.

Accordingly, the PCS 219 decodes the signal received from the PMA 217 by 10B / 8B, and delivers the signal to the upper layer through the 8-bit MAC signal GMII. At this time, the PCS 219 informs the controller 218 of the coding error information detected in the 10B / 8B decoding process so that the controller 218 can drive the selector 215.

Referring to the operation of the Ethernet link redundancy system according to the present invention having the structure as described above in detail as follows.

FIG. 4 is a detailed flowchart illustrating a process for processing a transfer request signal in a switching control method of an Ethernet link redundancy system according to the present invention, in which an error occurs in an Ethernet frame due to a failure in an Ethernet physical layer or a performance degradation of an Ethernet optical link. It shows the process to protect the faulty link when it occurs.

As shown in FIG. 4, when the Ethernet device is initialized (401), the PCS 219 of the Ethernet receiver (receiver 210) checks whether the 10-bit code group transmitted from the PMA 217 is correctly aligned. Verify. At this time, the code group determines that / C / or "idle ordered set", which are three "configuration ordered sets" starting with /K28.5/ containing commas, is synchronized when / I / is received. However, when the codeword / C / or / I / is not received due to the line failure, LOS (Loss Of Sysnc) occurs (402).

Therefore, when LOS occurs in the Ethernet link that is currently receiving traffic, the spare link failure state is checked (408), and if normal, the switch is switched to the spare link (409). Otherwise, the process determines whether the LOS occurs. Proceed.

On the other hand, when there is no MAC frame to be transmitted in Ethernet, the idle frame is continuously transmitted to facilitate clock extraction in the receiving PMA. Here, the idle frame includes / I1 / frame composed of /K28.5/D5.6/ and / I2 / frame composed of /K28.5/D16.2/. The / I1 / frame inverts the RD (Running Distance) so that RD becomes negative, and / I2 / keeps the RD always negative. Therefore, if the idle frame is continuously received, the RD value should always be (-). If the RD value of the idle frame becomes (+) or if (+) and (-) are repeated, the idle frame error. Can be judged.

Accordingly, when an idle frame error 403 is detected, an error occurs in some bits of some 8B / 10B encoded codewords due to the deterioration of the link. In case of normal operation, the process switches to the reserve link (409). Otherwise, the process proceeds to the process of determining whether the LOS is generated (402).

On the other hand, when the MAC of the receiving PCS client informs the transmitting terminal that there is a transmission error, / V / code /K30.7/ is used. Therefore, it can be seen that / V / code is being transmitted (404) from the transmitting PCS due to the performance degradation on the currently received operating link. 409), otherwise, the process proceeds to step 402 to determine whether LOS has occurred.

Meanwhile, in order to transmit a MAC frame, / S / code indicating a start boundary of a frame and / T / code indicating a last boundary of a frame are used. If, after receiving the / S / frame (405) a certain time, that is, the time when 1518byte is received (12ms) for 1GbE (1.2ms), 1.2ms for 10GbE elapsed (406) even if / T / frame is not received (407) Since the case is due to a failure or performance degradation on the operational link (step 408), if the normal state is switched to the spare link (409), otherwise proceeds to step 402 to determine whether the LOS occurs. The normal existence of the spare link and the operation link 408 may detect a coding error in the PCS layer on the link that is currently receiving data, but detect the loss of signal (LOS) in the PMD layer on the other link.

FIG. 5 is a detailed flowchart illustrating an embodiment of a switchover process in a switchover control method of an Ethernet link redundancy system according to the present invention.

As shown in FIG. 5, in the 1 + 1 protection switching, when the operation link returns to the normal state in the state of switching to the spare link, there is a return switching mode and a non-resilience mode that returns to the operation link which is the original link. It is checked whether the operational link is normal (501), and if it is normal, it is checked whether it is set to the return transfer mode (502), and if it is normal, it is returned to the operational link (503).

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention as described above, by providing a spare Ethernet link in the Ethernet link, when the operating Ethernet link is broken, by quickly switching the failed Ethernet link to the spare Ethernet link within 50ms, it is possible to prevent the deterioration of service quality and Ethernet network It has the effect of increasing the availability of SDH to SONET level.

In addition, since the present invention detects a coding error in the PCS, the Ethernet physical layer, and uses it as a control signal for switching, it is not necessary to use a packet for control separately in a higher layer, thereby performing a GBIC interface function so that a new PMD failure can be achieved. The module can be replaced immediately.

In addition, the present invention has the effect that the circuit can be simplified since protection switching is possible only by PMD duplication.

Claims (9)

In an Ethernet link redundancy system, A dedicated spare link is provided for one operation link connected between a transmitting and receiving node for transmitting and receiving an Ethernet signal, and the operating link and the spare link are bridged by bridging the operation link and the spare link in a transmission physical media dependent (PMD) layer. Transmitting means for transmitting each of the Ethernet signals through the network; And Receiving means for switching to a link in the normal state of the operational link or the spare link in the receiving PMD layer to receive the Ethernet signal on the link in accordance with the coding error detected in the decoding process Ethernet link redundancy system comprising a. The method of claim 1, The transmitting means, A media access received from a Gigabit Media Independent Interface (GMII) of Gigabit Ethernet (GbE), each including a first operating unit and a first spare unit including an optical transmitter for transmitting signals branched from the first signal converter; A first Physical Coding Sublayer (PCS) for encoding a Control signal, a first Physical Medium Attachment (PMA) for serially converting parallel signals from the first PCS, and a first PMA for 1 + 1 switching. And a first giga bit interface convert (GBIC) interface for interfacing the signal from the first signal converter to the first operating unit and the first spare unit for branching an output signal. Ethernet link redundancy system. The method of claim 2, The transmitting means, The same signal is always transmitted through the first operating part and the first spare part, and when a failure occurs in the first operating part or the first spare part and repair is required, the optical transceiver having the GBIC interface function is replaced. Ethernet link redundancy system, characterized in that to enable normal operation through. The method according to any one of claims 1 to 3, The receiving means, A second operating unit and a second spare unit including a photoreceiver for 1 + 1 switching, respectively, a Giga Bit Interface Convert (GBIC) interface for interfacing this signal from the second operating unit and the second spare unit; A signal selector for selecting signals from the second operating unit and the second spare unit received through a GBIC interface under control of a controller, a second signal converter for converting a received signal from the signal selector, and the second A second physical medium attachment (PMA) for extracting a clock from a received signal from a second signal converter, recovering data using the extracted clock, and converting the recovered data into parallel data, and the parallel converted through the second PMA A second physical coding sublayer (PCS) for decoding a signal into a MAC signal to detect a coding error, and coding error information from the second PCS Forwarding received Ethernet link redundancy system comprising: a controller for performing the switching control. The method of claim 4, wherein The second PMA is, And extracting a clock and data to extract the Ethernet frame received through the second signal converter, and detecting a preamble indicating the start of the Ethernet frame to synchronize the received frame. In the Ethernet link redundancy receiver, Operational receiving means for receiving and converting Ethernet signals over an operational link; Preliminary receiving means for receiving and converting an Ethernet signal through a preliminary link provided exclusively for the operation link; Interfacing means for interfacing received signals from said operational receiving means and said preliminary receiving means; Signal selection means for selecting a reception signal from the operational reception means or the preliminary reception means received through the interfacing means according to a control signal of a control means; Signal conversion means for converting the received signal from the signal selection means; A physical medium attachment (PMA) for restoring data and converting the data into parallel data using a clock extracted from the received signal from the signal converting means; A physical coding sublayer (PCS) for decoding a parallel signal from the PMA into a MAC signal to detect a coding error; And The control means for performing switching control by receiving coding error information from the PCS; Ethernet link redundancy receiver comprising a. In the switching control method of the Ethernet link redundancy system, Bridging the spare link with the spare link in a transmission PMD layer by setting a dedicated spare link for one operational link connected between a transmitting and receiving node for transmitting and receiving an Ethernet signal; A failure detection step of detecting, by the receiving node, a failure of the operation link based on a coding error detected by decoding an Ethernet signal received from the transmitting node; And Switching from the receiving PMD layer to the spare link by the receiving node when a failure of the operational link is detected; Switching control method of the Ethernet link redundancy system comprising a. The method of claim 7, wherein Checking whether the operational link is normal, and returning to the operational link according to the normal and resilient switching mode. Switching control method of the Ethernet link redundancy system further comprising. The method according to claim 7 or 8, The failure occurrence detection step, Coding error (LOS) of physical coding sublayer (PCS), idle frame error, transmission of / V / code, and / T / code not received after a certain time after receiving / S / code A switching control method of an Ethernet link redundancy system, characterized in that it is determined as an error when one state occurs.

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