KR101642440B1 - Network recovering method for ring network - Google Patents

Abstract

The present invention relates to a method for recovering from a network failure in a ring network, which enables accurate immediate switching on a per-packet basis in an optical network or a wired network including a copper-wire network without a separate change to a communication frame. An error check code is generated for a value to which an identification number varying with a predetermined pattern is additionally added when the error check code for a packet to be transmitted is generated in a ring network connected via wired lines having a relatively low possibility that error occurs in reception data, thereby intentionally causing an error corresponding to the corresponding identification number to occur when the ring network is restored and then allowing the identification number corresponding to the intentional error to be used as an ID adapted to identify a packet when the intentional error maintains the predetermined pattern according to a sequence of the transmission packet. Accordingly, a working packet and a protection packet, which have different reception times, are to be accurately matched with each other without a change in a communication frame which requires a configuration adapted to generate and analyze a non-standard communication frame and requires a decrease in compatibility, thereby providing an effect in which a configuration for enabling communication to be maintained without delay and packet loss during switching can be easily applied. The method comprises: a generation step of generating an error check code into which an identification number is added so that an error value corresponding to the identification number can be calculated; a transmission step of simultaneously transmitting, by a transmission node, a packet including the identification number in opposite directions of a ring network; a reception step of receiving, by a reception node, a working packet received in a set direction and a protection packet received in an opposite direction; and a switching step of performing, by the reception node, switching based on information about a match between the protection packet and the working packet.

Description

[0001] The present invention relates to a network recovery method for ring network,

The present invention relates to a line fault recovery method for a ring network, and more particularly, to a line fault recovery method for a ring network in which an accurate packet-by-packet switching is possible without changing a communication frame in a wired network including an optical network or a copper line network will be.

A ring network is a network in which the nodes are connected in a loop, and the communication takes place from one node to another in a fixed direction until reaching the receiving node.

In this ring network, all nodes are connected in the shape of a ring. Therefore, if one of the lines connecting the nodes fails and the connection between the transmitting node and the receiving node is disconnected, .

Generally, as a protection switching method for maintaining the reliability of communication, there are a 1: 1 switching method in which an additional channel is preliminarily configured in a different path in addition to a working channel to be used and then switched to another path previously configured when a trouble occurs in the working channel, Or module as a working channel and maintains communication by using another channel when a failure occurs in one line and a 1 + 1 switching type linear switching method and a ring network as described above to change the communication direction in case of line failure Ring protection switching method.

In general, IP layer has protection function in TCP / IP. However, since the path is calculated through the routing table in the case of line failure, the packet is sent according to the header of the IP packet according to the header of the new packet. Communication can not be performed, and therefore, in a network where reliability is required, the above-mentioned line switching method in the network layer is mainly used.

FIG. 1 shows a general ring network structure. When a packet is to be transmitted from the master node 10 to the first node 20, the path is transmitted through a line connected to the first node 20, 40 to the first node 20 through the third node 40 and the second node 30 through a path connected to the second node 40. [

Generally, in case of a ring network, a packet to be transmitted is transmitted to a neighboring node in one direction, and the receiving node checks whether the destination address of the packet is itself, and if not, transmits the packet to another neighboring node in the same direction.

If the line or node that constitutes the ring network operates normally, communication between arbitrary nodes becomes possible even if communication is performed in only one direction.

In such a ring network configuration, if a failure occurs in one line, it is common to reverse the communication direction to reverse the fault. However, a considerable delay occurs until the receiving node receives the packet by retransmitting the communication in the opposite direction for recovery Therefore, in order to construct a reliable ring network, a method of transmitting a working packet in one direction and transmitting a protection packet in the other direction can be used.

However, in this case, since most of the inter-node communication is received at the different timing of the working packet and the protection packet due to the difference in the transmission distance, the protection packet corresponding to the working packet not received when the working packet is not received due to the failure It is difficult to distinguish. That is, it is difficult to clearly identify the same protection packet as the working packet.

Although the buffered protection packets corresponding to the normally received packets can be found by comparing the data of the packets, when a delay occurs in the process of comparing the packets and a plurality of packets having similar data are received It is difficult to specify a protection packet corresponding to an unreceived working packet.

In order to solve this problem, it is possible to additionally add an identifier for identifying a packet to a frame for transmitting a packet.

In Korean Patent Laid-Open No. 10-2013-0134422, 'frame lossless communication method using frame-based routing in ring network topology', an additional sequence number (identifier) field is added to a frame in order to check the identity of a bidirectional packet .

In addition, Korean Patent No. 10-1543671, 'Packet processing method and apparatus in ring network', adds tag information for identification to a data packet while using High-availability Seamless Redundancy (HSR) protocol, which is a lossless switching scheme standard Is disclosed.

As described above, the existing conventional technologies are a method of adding additional identifier information to the header of data to be transmitted in order to specify packets in the ring network. When customizing the communication protocol, there is a problem in that it is not easy to be applied in terms of design, mass production and compatibility Of course, the additional information needs to be added every frame, so that the transmission speed is lowered.

Therefore, there is a need for a new method that enables a reliable protection switching by accurately matching a working packet and a protection packet on a packet-by-packet basis without changing an existing communication frame in a ring network structure.

Korean Patent No. 10-1519624 [Title of the invention: Failure recovery method in non-reducing mode of Ethernet ring network] Korean Patent Laid-Open No. 10-2013-0134422 [Description of the Invention: Frame Lossless Communication Method Using Frame-Based Routing in Ring Network Topology] Korean Patent No. 10-1543671 [Description of the Invention: Packet processing method and apparatus in ring network]

An object of the present invention to solve such a problem is to generate a CRC (cyclic redundancy check) for a packet to be transmitted in a ring network connected to a wired line having a relatively low possibility of receiving data error A value obtained by further adding an identification number changed according to a predetermined pattern is generated as a target so that an error corresponding to the identification number is generated when the data is intentionally restored, The identification number corresponding to the intentional error is used as the identifier for identifying the packet, so that the working packet and the protection packet having different reception times are matched without changing the communication frame, Of the ring network of a ring network so that it can be maintained It is.

Another object of the present invention is to transmit data in both directions at the time of data transmission in a ring network, receive a working packet and a protection packet in a receiving node and store the received working packet and protection packet in a buffer, The present invention provides a method of restoring a line fault in a ring network by outputting a working packet when all the same packets are stored in a reception buffer, thereby promptly outputting a protection packet stored in a reception buffer when a failure occurs in one line .

In the line fault recovery method of a ring network according to an embodiment of the present invention, when generating an error check code for a packet to be transmitted from a transmitting node, an identification number is added so that an error value corresponding to the identification number is calculated in the error check code verification process An error check code generation step of: A transmitting step in which a transmitting node simultaneously transmits a packet including an identification number in both directions of a ring network; The receiving node receives the working packet received from the set direction and the protection packet received in the opposite direction and stores them in the receiving buffer, respectively, while verifying the error check code of the received packet to calculate the identification number corresponding to the error, A matching step of matching a packet having the same identification number among the working packet and the protection packet; And a switching step of performing switching based on the matching information of the protection packet and the working packet stored in the buffer in the line failure when the receiving node receives the working packet.

The error checking code generating step may include changing the identification number according to the promised pattern according to the packet order. In particular, the step of generating an error checking code includes separately applying a destination address of the frame for packet transmission and an identification number for each source address, and the receiving step separates the packet through the combination of the destination address and the source address and the identification number Step < / RTI >

The identification number may be a unique value for each packet received in the receive buffer.

The promised pattern may be a sequentially increasing or decreasing number of n bits in size.

The receiving step may include a step of verifying an error check code for the received packet and judging the received error as a reception error if the pattern is different from the promised pattern.

The error checking code may be a cyclical redundancy check (CRC).

The switching step may include outputting, as an output, a subsequent packet of a protection packet corresponding to a last received working packet in a line failure for receiving a working packet.

The line failure recovery method of a ring network according to another embodiment of the present invention is a method of recovering a line failure of a ring network by generating a CRC code for an Ethernet packet to be transmitted from a transmitting node, A CRC code generation step of adding an identification number to be calculated; A transmitting step in which a transmitting node simultaneously transmits a packet including an identification number in both directions of a ring network; The receiving node receives the working packet received from the set direction and the protection packet received in the opposite direction, stores it in each reception queue, verifies the CRC code of the received packet, calculates an identification number corresponding to the error, A receiving step of matching a packet having the same destination address, source address and identification number among the stored working packet and the protection packet, respectively; And a switching step in which the receiving node performs switching based on the matching information of the protection packet and the working packet stored in the reception queue in the case of a line failure.

In the CRC code generation step, a numeric ID number sequentially increasing or decreasing by n bits may be applied according to the packet order.

The line fault recovery method of a ring network according to an embodiment of the present invention is characterized in that when generating an error check code for a packet to be transmitted in a ring network connected to a wired line having a relatively low possibility of receiving data error, And an error corresponding to the identification number is generated when the data is intentionally restored. If such an intentional error keeps a pattern promised according to the order of the transmitted packets, an intentional error It is possible to precisely match a working packet and a protection packet having different reception timings even if there is no communication frame change requiring reduction in compatibility with the configuration for generation and analysis of non-standard communication frames Without delay and packet loss on switching There is an effect that can be readily applied to a configuration in which God can be maintained.

In addition, according to the embodiment of the present invention, in the method of restoring a line fault in a ring network, an intentional error corresponding to an identification number is generated in generating an error check code. By generating such a pattern between identification numbers in a predetermined pattern, It is possible to verify the normal reception by confirming that the identification number according to the intentional error obtained from the confirmation code conforms to the promised pattern and at the same time the identification number of the packet can be confirmed so that a plurality of Function is performed.

The line failure recovery method of a ring network according to an embodiment of the present invention transmits data in both directions at the time of data transmission in a ring network and receives a working packet and a protection packet in a receiving node and stores the working packet and the protection packet in a buffer, A protection packet stored in the reception buffer is immediately output when a failure occurs in one of the lines without requiring a change in the system hardware configuration by outputting a working packet when packets having the same identification number added to the error confirmation code are all stored in the reception buffer, It is possible to provide a high economical efficiency.

1 is a conceptual diagram showing a configuration example of a ring network;
2 is a conceptual diagram of a packet transmission method in both directions of a ring network.
3 illustrates an example of a receive queue of a receiving node receiving packets across both directions of the ring network;
4 is a simple communication frame structure diagram.
5 is a block diagram of a ring network protection switching system according to an embodiment of the present invention.
6 to 9 are conceptual diagrams illustrating an operation method of a ring network protection switching system according to an embodiment of the present invention.
10 is an exemplary diagram for showing a receiving queue matching state of a receiving node according to an embodiment of the present invention.
11 is a flowchart illustrating a ring network protection switching process according to an embodiment of the present invention.

It is noted that the technical terms used in the present invention are used only to describe specific embodiments and are not intended to limit the present invention. In addition, the technical terms used in the present invention should be construed in a sense generally understood by a person having ordinary skill in the art to which the present invention belongs, unless otherwise defined in the present invention, and an overly comprehensive It should not be construed as meaning or overly reduced. In addition, when a technical term used in the present invention is an erroneous technical term that does not accurately express the concept of the present invention, it should be understood that technical terms that can be understood by a person skilled in the art can be properly understood. In addition, the general terms used in the present invention should be interpreted according to a predefined or context, and should not be construed as being excessively reduced.

Furthermore, the singular expressions used in the present invention include plural expressions unless the context clearly dictates otherwise. The term "comprising" or "comprising" or the like in the present invention should not be construed as necessarily including the various elements or steps described in the invention, Or may include additional components or steps.

In addition, terms including ordinals such as first, second, etc. used in the present invention can be used to describe elements, but the elements should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or similar elements throughout the several views, and redundant description thereof will be omitted.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It is to be noted that the accompanying drawings are only for the purpose of facilitating understanding of the present invention, and should not be construed as limiting the scope of the present invention with reference to the accompanying drawings.

In the description of the present invention, terms such as a packet and a frame are used. However, the present invention is not limited to the specific meaning on the transport layer, and the technical principle of the present invention can be applied If so, the application of the technology as a specific layer is not limited.

The present invention relates to a fault recovery method capable of quickly performing a protection switching in a ring network formed by using a relatively stable wired physical medium line such as an optical line or a copper line.

To this end, in the present invention, a transmitting node transmits a packet to be transmitted in a predetermined direction and also transmits the packet in the opposite direction, so that a receiving node can receive a working packet and a protection packet in different directions, Even if a failure occurs in the line, the failure can be recovered through the transfer using the protection packet received in the opposite direction. In the case of the ring network, the distance between the transmitting node and the receiving node differs according to the communication direction. Since the receiving point of the working packet and the protection packet differ from each other due to such physical or electrical distance difference, It is possible to distinguish the same protection packet from the working packet without changing the hardware or changing the frame structure.

FIG. 2 shows a concept of a packet transmission scheme in both directions of a ring network. For example, when a packet is transmitted from the master node 10 to the node 1 20 as a receiver node, The working packet W_P is received prior to the protection packet P_P transmitted to the first node 20 via the third node 40 and the second node 30 via the leftward line.

That is, since the first protection packet P_P is received after the working packet W_P is received as shown on the right side in the case of the first node 20 serving as the receiving node, a difference occurs at the receiving time point. In addition, since the ring network is an environment in which the nodes perform mutual communication, the reception order of the working packet and the protection packet received by the receiving node is not constant and may be mixed in different orders according to the distance. It becomes difficult to clearly distinguish the protection packet from the protection packet.

Therefore, a protection packet corresponding to a specific working packet must be found and matched to enable fast switching without a packet loss in the event of a failure.

For this, there is a method of comparing the entire data structure of the packet to compare the working packet with the protection packet, and finding the same protection packet as the working packet. However, in this case, It is difficult to distinguish the cases.

Therefore, a method of adding a unique identifier for packet classification is an effective method that can be practically implemented.

3 is an exemplary diagram illustrating a receive queue of a receiving node receiving packets across both directions of the ring network; As shown in the figure, a working packet queue and a protection packet queue, in which a working packet and a protection packet are received and sequentially stored, are distinguished from each other.

3A shows a case in which a short working path and a long protection path exist between a transmitting node and a receiving node, and FIG. 3B shows a case where a long working path and a short protection path exist between a transmitting node and a receiving node to be.

As shown in FIG. 3A, a packet corresponding to a protection packet queue is received after a packet indicated by a hatched packet is received in a working packet queue. FIG. 3B shows a case where a packet marked as hatched in the protection packet queue is received, Lt; / RTI > is received. That is, according to the inter-communication node arrangement, a working packet may be received first and a protection packet may be received first.

Meanwhile, in order to switch according to the failure, the same packet is always received in both the working packet queue and the protection packet queue, and then the corresponding packet is output from the working packet queue. In order to do this, the matching relation between the working packet and the protection packet stored in the reception queue must be confirmed, so that unique identification information of the packet is needed.

FIG. 4 shows a simple communication frame structure, and shows a simplified structure of an Ethernet frame. As shown in the figure, a destination address, a source address, type information, data, and an error check code (e.g., cyclic redundancy check (CRC)) for such information are configured.

In the case of such a standard communication frame, since there is no field for defining a separate identifier for identifying a packet, the frame structure should be changed in order to include an identifier for identifying the packet. However, if the frame structure is changed, it is necessary to change the configuration to process the frame. Therefore, a new design or mass production is required, and existing commercialized processing configurations are not available, . Particularly, when a new identifier field is added to a frame, the transmission speed is delayed and the performance is lowered.

Therefore, in the embodiment of the present invention, a reliable protection switching can be performed by inserting an identifier that can accurately match the working packet and the protection packet stored in the buffer of the receiving node without changing the existing packet frame in the ring network structure . In particular, by enabling such functions to be performed through software changes, it is possible to maintain the compatibility by using the functions according to the embodiments of the present invention or conforming to the existing standards according to the operation mode, thereby improving the usability and applicability .

FIG. 5 is a block diagram of a ring network protection switching system according to an embodiment of the present invention, in which the operation of the transmitter 100 and the receiver 200 of the node are different. A node connected to the ring network capable of protection switching constitutes the transmitting unit 100 and the receiving unit 200, so that the unique identifier of the packet can be distinguished without changing a communication frame.

First, the transmitter 100 includes a frame generator 130 for generating a frame including a packet. The transmitter 130 may use the conventional conventional frame generator 130 as it is. The CRC calculation unit 120 includes an identifier for identifying a corresponding packet in a CRC to be used when generating a frame including such a packet, and an identifier having a predetermined promised pattern for each generated packet to the CRC calculation unit 120 And an identifier generator 110 for generating an identifier.

Here, the identifier generation unit 110 includes a step of changing the identification number according to the promised pattern according to the packet order, and this pattern may be, for example, a sequentially increasing or decreasing number of n bits in size. Of course, it may be a pattern obtained according to a specific mathematical expression or a pattern such as a known separable sequence.

As a simplest example, an identifier may be defined as 8-bit information identifying a packet and incremented from 0 to 1 according to the packet order. Basically, an identifier for such a packet classification is preferably a unique code, but it may be an implementation-limited unique code.

This identifier can be designed to have a variable size depending on the difference between the used line and the protection line. The queue size that can compensate for a distance difference of less than 100 Km is usually a number of packets buffered in the reception buffer (packet queue) Given that there are about 100 (in the case of optical lines), even if the range of 0 to 255 is repeated, the packets in the buffer can have uniqueness. Of course, if the size of the ring network is large or the reception delay time is longer than the transmission rate, the size of the identifier may be increased or vice versa.

If the communication between the nodes is substantially performed, the packet reception order of the working packet queue 210 and the protection packet queue 220 becomes different due to the difference between the usage path and the protection path. Therefore, It is preferable to separately generate each source address. That is, an identification number (for example, 0 to 255) generated for a packet transmitted from the master node to the first node and an identification number (for example, 0 to 255 ) Can be separately managed. Therefore, even if the identification numbers are the same, packets having different destination addresses and source addresses can be distinguished as having different identifiers.

On the other hand, when generating an error check code for a packet to be transmitted from a transmitting node (for example, when generating a CRC for the frame), the CRC calculator 120 calculates an error corresponding to the identification number Add an identifier so that the value is calculated. For example, if identification number 1 is inserted as an identifier, a CRC value is generated such that the error value becomes 1 in the CRC verification process.

The receiving unit 200 includes a working packet queue 210 for storing received packets and a protection packet queue 220 for protection switching and includes a CRC verifying unit 230 for verifying a CRC for a received frame including a packet ).

If the CRC verification unit 230 verifies the CRC for the received frame by inserting the number corresponding to the identifier in the transmitter 100, the CRC verification unit 230 may calculate an error value corresponding to the identifier. If the error is calculated, it is not determined that the error is a reception error but the received error is verified by checking whether the pattern of the calculated error is a promised pattern, and an identifier of the packet is obtained at the same time. For example, if the error calculated for the previous packet is 1 and the promised pattern is a value that increases by 1, it is determined that reception is normal and that the identifier is 2 if the calculated error is 2. If this error is not a promised pattern, it can be judged as a reception error.

Meanwhile, the identifier information obtained according to the verification can be used to identify the packet together with the destination address and the source address of the received frame.

The identifier matching unit 240 identifies an identifier of the received packet determined by the CRC verification unit 230 and a destination address and a source address of a frame of the packet, and outputs a working packet and a protection message, which are stored in the working packet queue 210, Among the protection packets stored in the packet queue 220, a pair of packets having the same identifier among the packets having the same destination address and source address of the frame.

Here, the matching may mean that the relation between the working packet and the same protection packet is separately stored. However, the matching information includes the identifier information of the working packet stored in the reception queue and the identifier information of the protection packet (including the destination / source address of the corresponding frame) It can be a comprehensive meaning to manage. In particular, when the protection packet corresponding to the working packet is included in the reception queue, the identifier matching unit 240 outputs the working packet as the reception packet, so that the identifier matching unit 240 can maintain the state in which the switching can be performed immediately.

The switching unit 250 can perform switching based on the matching information of the protection packet stored in the reception queues 210 and 220 and the identifier matching unit 240 for the working packet. For example, the switching unit 250 may output the next packet of the protection packet corresponding to the last received working packet in line failure, using the matched information in the identifier matching unit 240.

The operation according to the embodiment of the present invention will be described in more detail with reference to FIGS. 6 to 9. FIG.

FIG. 6 is a diagram for explaining a CRC calculation method. As shown in FIG. 6, a CRC is calculated using information of a header and a data portion of a frame, and the CRC is added to the end of the frame to generate frame data do.

The CRC calculation is one of several known error checking codes.

When there is n bits of information given, it is shifted up by k bits and divided by the key value of the promised k bits, leaving the remainder of the r bits. On the transmitting side, the original information bit is added to the k bit position and the rest of the r bit is added to generate n + r bits of data. The receiving side divides the received n + r bits of data by the key value and verifies whether the remainder is equal to 0 and verifies the error. If an error occurs, the receiver requests retransmission of the corresponding data.

Of course, the error checking code of the present invention is not limited to the CRC, but may be various other redundant checking codes (e.g., checksum, Longitudinal Redundancy Check (LRC), etc.).

7 shows a process of inserting the identifier generated by the CRC calculation unit 120 into the CRC by the identifier generation unit 110. When calculating the CRC using the information of the header and data part of the frame to be transmitted, A CRC calculation unit 120 generates an identifier generated in accordance with a promised pattern so as to calculate an error in verification, and inserts it into the end of the corresponding frame.

For example, when an identifier is generated so that the identifier generating unit 110 has an 8-bit number and a value incrementing by 1 sequentially for each packet, the identifier may be continuously generated from 0x01 to 0xff repeatedly. The CRC calculation unit 120 inserts the identifiers generated by the identifier generation unit 110 one by one for each packet to be transmitted, and generates a CRC for intentionally generating a corresponding error. Of course, more bits can be used or fewer bits can be used for identifier generation, and promised patterns can be applied to various patterns other than simple increase / decrease.

FIG. 8 shows a concept of applying sequential identifiers to a plurality of sequential frames. The CRC 1 is inserted after the identifier 1 is inserted in the first frame, and the CRC 1 is added. In the second frame, An identifier 2 is inserted to calculate the CRC2 for which the error is intended, and then the CRC2 is appended. In the third frame, the identifier 3 changed in the pattern promised in the identifier 2 is inserted to calculate the CRC3 for which the error is intended.

Since the size of the identifier may be limited, it may be a smaller value again after a predetermined maximum value. For example, if the value is an 8-bit value that increases by 1, the identifier after 0xff may be 0x00, and it may reflect this when checking the identifier pattern.

Of course, as described above, these identifiers can be separately generated based on the destination address and the source address, and can be used as identification information for distinguishing packets together with the destination address and the source address.

FIG. 9 shows a concept of CRC verification in a receiver that receives a frame having an error-intended CRC in the manner described above. As shown in FIG. 9, the CRC verification unit 230 generates a CRC And the intended error corresponding to the identifier when it is normally received is calculated.

FIG. 10 conceptually shows identifier matching of a working packet and a protection packet received at a receiving node and stored in a receiving queue.

In the illustrated case, the master node 10 transmits a packet to the node 1 20 in the configuration of FIG. 2 as an example.

When data is transmitted from the master node 10 to the node 1 20, the working packet transmitted in the communication direction (right side, use direction) in use is transmitted from the protection packet transmitted in the communication direction for the protection (left side, And arrives first at the node 1 (20).

The arriving working packet is stored sequentially in the working packet queue, and the identifier corresponding to the packet is calculated in the frame and regarded as a unique identifier of the corresponding packet. In the illustrated example, it is indicated as < identifier > under the square block indicating the packet.

The protection packet is received by the protection packet queue slower than the working packet due to the transmission length, and is sequentially received. The unique identifier of the packet is extracted.

(Identifiers 3 and 4) of the protection packet queues corresponding to some working packets (identifiers 3 and 4) of the working packet queue can be corresponded to each other. If there is a packet corresponding to the reception queue, Therefore, the corresponding working packet (identifiers 3 and 4) can be output, and can be switched quickly when switching is required.

On the other hand, it can be seen that the integrity of the received packet can be verified by using this pattern because the identification number sequentially increases in the patterns of the illustrated identifiers.

As a result, an identifier (identification number) promised in the CRC calculation process is inserted so that an error value becomes a corresponding identifier in verification, and the identifier has a constant pattern in accordance with successive packets, It is possible to verify the packet error and to transmit the assigned identifier information together, so that the CRC can be expanded and utilized without having to change the frame.

That is, not only can the same packet among the working packet and the protection packet received in the mixed order through the destination address, the source address, and the identifier information inserted in the CRC be distinguished at the frame data level, There is no problem that the transmission speed is lowered because there is no change in the fields constituting the frame.

11 is a flowchart illustrating a ring network protection switching process according to an embodiment of the present invention.

When a frame corresponding to a packet to be transmitted by a transmitting node is intentionally generated, a CRC that generates an error corresponding to the identifier is inserted to transmit the packet. At this time, an identification number to be used as an identifier based on the destination address and the source address may be applied.

Such packet transmission is simultaneously performed in the use direction of the ring network and the protection direction for protection switching.

The receiving node receives the packet and stores it in the reception queue. The CRC of the frame for each packet is stored while being stored in the working packet queue and the protection packet queue, and the error is calculated.

If the CRC verification error confirms that the previously received verification error and the promised pattern are maintained, the value corresponding to the verification error is regarded as the identifier of the corresponding packet if it is the promised identifier pattern. If the packet is not the promised identifier pattern, the packet is erroneously received, so it may request retransmission or correct based on the normally received working / protection packet information.

When the same protection packet as that of the working packet is received (or conversely, the protection packet can be received first), the working packet and the protection packet received in the reception queue are collected, And the same protection packet as that in the reception queue exists in the reception queue), the fast switching can be performed, so that the working packet can be output as the received packet. In this case, packets having the same destination address and source address are matched with the same packet with the same identifier information.

If an error occurs in the reception of the working packet, there may be an error in the line or node in the receiving path. In this case, the receiving node may determine that the switching is necessary.

If it is determined that the switching is necessary, the receiving node can perform immediate switching based on the matching information of the protection packet and the working packet stored in the reception queue. For example, it is possible to provide, as an output, a subsequent packet of a protection packet corresponding to the last received working packet (a protection packet having an identifier following the identifier of the last received working packet).

Through this process, reliable real-time line failure recovery becomes possible.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or essential characteristics thereof. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

10: master node 20 to 40: node 1 to node 3
100: Transmitter 110: Identifier generator
120: CRC calculation unit 130:
200: Receiving unit 210: Working packet queue
220: protection packet queue 230: CRC verification unit
240: an identifier matching unit

Claims (10)

A method for restoring a line fault in a ring network,
An error check code generation step of adding an identification number so that an error value corresponding to an identification number is calculated in an error check code verification process when generating an error check code for a packet to be transmitted from a transmitting node;
A transmitting step in which a transmitting node simultaneously transmits a packet including an identification number in both directions of a ring network;
The receiving node receives the working packet received from the set direction and the protection packet received in the opposite direction and stores them in the receiving buffer, respectively, while verifying the error check code of the received packet to calculate the identification number corresponding to the error, A matching step of matching a packet having the same identification number among the working packet and the protection packet;
And a switching step of performing a switching based on matching information of a protection packet and a working packet stored in a buffer in a line failure when the receiving node receives a working packet.
The method according to claim 1, wherein the step of generating an error check code comprises changing an identification number according to an expected pattern according to a packet order.
The method of claim 2, wherein the generating of the error checking code comprises separately applying a destination address of a frame for packet transmission and an identification number for each source address,
Wherein the receiving step comprises the step of discriminating a packet through a combination of a destination address, a source address and an identification number.
The method of claim 2, wherein the identification number is a unique value for each packet received in the receive buffer.
3. The method of claim 2, wherein the promised pattern is a sequentially increasing or decreasing number of n bits in size.
The method of claim 2, wherein the receiving step includes verifying an error check code for a received packet and determining a reception error if the pattern is different from the promised pattern.
The method of claim 1, wherein the error check code is a cyclic redundancy check (CRC).
The method according to claim 1, wherein the switching step includes outputting, as an output, a subsequent packet of a protection packet corresponding to a last received working packet in a line failure for receiving a working packet .
A method for restoring a line fault in a ring network,
A CRC code generation step of adding an identification number so that an error value corresponding to an identification number capable of identifying a corresponding packet is calculated in a CRC code verification process when generating a CRC code for an Ethernet packet to be transmitted from a transmitting node;
A transmitting step in which a transmitting node simultaneously transmits a packet including an identification number in both directions of a ring network;
The receiving node receives the working packet received from the set direction and the protection packet received in the opposite direction, stores it in each reception queue, verifies the CRC code of the received packet, calculates an identification number corresponding to the error, A receiving step of matching a packet having the same destination address, source address and identification number among the stored working packet and the protection packet, respectively;
And a switching step in which the receiving node performs a switching based on the matching information of the protection packet and the working packet stored in the reception queue in case of a line failure.
[12] The method of claim 9, wherein the CRC code generation step comprises applying a numerical identification number sequentially increasing or decreasing in n-bit order according to a packet order.

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