KR20180018995A - Ring network having lpfr algorithm - Google Patents

Abstract

The present invention relates to a ring network having an LPFR algorithm, comprising: a source node having at least two ports and transmitting a data frame to a destination node via at least two ports; And a destination node for receiving a data frame transmitted from the source node, wherein the source node designates, as a node main port, port information on which of the at least two ports the data frame is to be transmitted to the destination node, If the main port, which is the port used to transmit the data frame to the destination node, is judged to have failed, the transmission path of the source node is switched so as to transmit the data frame to the destination node through the remaining port other than the main port of the source node, Change the node's major ports according to path switching . As a result, the source node recognizes that the inter-node link disconnection occurs, and transmits the frame in the other direction. By recognizing that the inter-node link disconnection occurs in both directions, the source node does not transmit the frame to be transmitted, There is an effect of improving the load balance.

Description

A ring network having an LPFR algorithm {RING NETWORK HAVING LPFR ALGORITHM}

The present invention relates to a ring network having an LPFR (Loop Prevention and Fast Recovery) algorithm, and more particularly to a ring network having an LPFR algorithm capable of preventing loops and distributing the load.

In transmitting data from a source node to a destination node in a network that includes a plurality of nodes and has a ring topology, an intra-network loop may occur due to a link disconnection between the nodes included in the transmission path, .

Accordingly, when a link disconnection occurs between nodes in a ring network in order to solve the problem of deterioration in network performance due to a link disconnection, the reliability of the network is maintained by switching the transmission path to an alternative path that does not include a failed link .

However, there is a problem that it takes a long time to search for an alternative route. In this case, the RSTP (Rapid Spanning Tree Protocol) algorithm, which takes less time for alternative routes such as Korean Patent No. 1442567, .

However, according to the prior art in which alternative routes are proposed using the RSTP algorithm, it is not possible to prevent a portion where a frame loss occurs when a node indicated by an alternative route is switched, so that switching time to an alternative route is small, A network structure in which no frame loss is required is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to improve the reliability of a network by quickly switching to an alternative path when a failure occurs between nodes constituting the network.

A ring network with an LPFR () algorithm according to an embodiment of the present invention includes a source node having at least two ports to transmit a data frame to a destination node via any of the at least two ports, And a destination node connected to or connected to a relay node and receiving the data frame transmitted from the source node, wherein the source node transmits the data frame through the port of the at least two ports to the destination node (NPP), and when it is determined that a main port, which is a port used for transmitting a data frame to the destination node, is broken, the port of the source node is not the main port of the source node And to transmit the data frame to the destination node via the remaining port And switch the transmission path to the source node group, characterized in that for changing the node main port in accordance with the transmission path switching.

Further comprising at least one relay node located between the source node and the destination node and relaying transmission of the data frame from the source node to the destination node, When a link disconnection between the relay nodes or a failure occurs in the port from the at least one relay node to the destination node, the at least one relay node sends back the data frame to be transmitted to the destination node toward the source node Wherein the at least one relay node has at least two ports, and the port information about which of the at least two ports provided in the relay node to transmit the data frame to the destination node, node primary port), and the port selection Frame and the node main port change the port selection frame and the node main port when a failure occurs in a link between the source node and the relay node or a port from the at least one relay node to the destination node .

And the source node or the at least one relay node broadcasts the port selection frame to the source node or the network to which the at least one relay node belongs.

Wherein the source node or the at least one relay node has a table for designating a node principal port (NPP) for each node other than its own node in the network to which the node belongs, and the source node or the at least one relay node The source node or the at least one relay node changes the NPP table when a failure occurs in the port of the source node or the relay node, And broadcast.

If the at least one relay node has transmitted the data frame back to the source node, the source node transmits the data frame to the destination node over a different transmission path according to the changed node primary port, And the path may include at least one relay node.

The source node transmits the data frame to the destination node through the another transmission path but a port failure or a link disconnection occurs in the other transmission path to return the data frame to the source node in the other transmission path The source node stops transmitting the data frame to the destination node when the source node receives the data frame back through both directions.

The source node or the at least one relay node generates a port down (PD) frame and broadcasts the changed NPP table as a failure occurs in the source node or the at least one relay node, And the source node or other nodes belonging to the network to which the relay node belongs confirm the failure state through the port down frame.

When a failure occurs in the source node or the at least one relay node, broadcasts a port up (PU) frame as a failure is recovered, and the source node or other nodes belonging to the network to which the relay node belongs And the node recovery state is confirmed through the port up frame.

All of the nodes other than the source node among all the nodes belonging to the source node or the network to which the relay node belongs transmit a network monitoring status (NMS) frame notifying whether the node is in the network normal state to the source node The root node receives the network monitoring status frame to determine a network failure status. If the network failure status is determined, the network node generates a network failure (NF) frame and broadcasts the frame to the nodes included in the network And controls to restart the nodes included in the network.

Wherein the source node or all nodes belonging to the network to which the relay node belongs periodically transmit the network monitoring status frame to the source node and the source node is a root node and the source node or the relay node belongs to the network to which the relay node belongs And generates the network failure frame if the network monitoring status frame is not received from all the nodes within the period.

According to this aspect, the source node of the ring network having the LPFR algorithm according to an embodiment of the present invention recognizes that the inter-node link disconnection occurs, and transmits the frame in the other direction, The source node does not transmit the frame to be transmitted, thereby improving the load balance of the network and preventing the frame loss due to port switching.

The ring network having the LPFR algorithm according to an embodiment of the present invention recognizes the link failure occurring in the frame transmission path of the source node and quickly switches the node to the opposite path. Therefore, the network failure recovery time By making it almost zero, the reliability of the network can be improved.

1 is a diagram schematically illustrating a ring network to which a ring network having an LPFR algorithm according to an embodiment of the present invention is applied.
2 is a diagram illustrating a frame structure of a ring network having an LPFR algorithm according to an embodiment of the present invention.
3 is a view for explaining the operation of a ring network having an LPFR algorithm according to an embodiment of the present invention.
4 is a diagram for explaining the operation of a ring network having an LPFR algorithm according to another embodiment of the present invention.
5 is a flowchart illustrating an operation of a ring network having an LPFR algorithm according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Hereinafter, a ring network having a Loop Prevention and Fast Recovery (LPFR) algorithm according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, a basic structure of a ring network having an LPFR algorithm according to an embodiment of the present invention will be described with reference to FIG.

As shown in Fig. 1, the basic structure of the present invention includes a node A (1) and a node B (2), and all nodes included in the network are connected in a ring structure.

More specifically, node A (1) and node B (2) have port 1 and port 2, respectively, where port 1 of node A (1) and port 1 of node B The port 2 of A (1) and the port 2 of the node B (2) are connected by a link.

1, a node A 1 can transmit a frame carrying data as a source node to another node, and a node B 2 can transmit a frame carrying data as a source node to a source node And receives the frame transmitted directly or through another node.

In one example, the destination node may be directly connected to the source node A (1) and receive the frame transmitted from the source node directly as in the embodiment of FIG. 1, but as another example, the source node A ) And the destination node B (2), the destination node B (2) receives the frame transmitted from the source node through the relay node.

Here, in an example in which the destination node receives a frame transmitted from the source node through the relay node, the number of relay nodes located between the source node and the destination node may be one or more, but is not limited thereto.

However, when a plurality of relay nodes are formed between the source node and the destination node, since the plurality of relay nodes are components of the network having the ring topology, the plurality of relay nodes are connected to each other in the ring topology .

In order for the frame transmitted from the source node to be transmitted to the destination node through the plurality of relay nodes, the plurality of relay nodes confirm the address of the destination node included in the frame transmitted from the source node and transmit the frame to the destination node At this time, the frame transmitted from the source node to the destination node has the structure shown in Fig.

2, a frame 10 transmitted from a source node to a destination node includes a MAC address 11 of a destination node, a MAC address 12 of a source node, a serial number 13, a unique code 14, A payload 15, and a CRC 16.

2 will be described in more detail with reference to the network having the ring structure of FIG. 1, the MAC address 11 of the destination node is the MAC address of the node B (2) And the MAC address 12 of the source node includes the MAC address of the node A (1).

In this case, when the frame 10 of FIG. 2 is to transmit data from the source node A (1) to the destination node B (2), the MAC address 12 And a MAC address 11, which is a physical address of a destination node, which is a destination to receive data to be transmitted from the source node. Thus, although not shown in FIG. 1, When the node 10 receives the frame 10 of Fig. 2, it can know from which source node the frame 10 is transmitted and to which destination node it should arrive.

At this time, the data to be transmitted from the source node to the destination node corresponds to the payload 15 of the frame 10.

Continuing, with reference to Fig. 2, each item of the frame 10 will be described. The serial number 13 includes the order information of the frame.

The inherent code 14 includes all the nodes included in the operation of transferring the frame from the source node to the destination node, for example, the source node that transmits the frame, the destination node that receives the frame, And a code indicating status information of at least one relay node relaying frame forwarding.

More specifically, the inherent code 14 is used to provide status information of each node for transmission path recovery in the event of a failure on a link formed between the nodes constituting the network, that is, on the frame transmission path.

The inherent code 14 is assigned to each of the source node, the destination node, and the relay node. In transmitting the frame 10 from the source node to the destination node, the frame 10 in which the specified unique code 14 is reflected .

At this time, the inherent code 14 can be included in the frame 10 as state information of the node in any one of the following five frames.

In one example, five types of native code 14 are: a port select (PS) frame, a port down (PD) frame, a port up (PU) , a network monitoring status frame, and a network failure (NF) frame.

In this way, among the unique codes 14 having five different frame types, the port selection frame is broadcasted from a specific node to all nodes of the network, and all nodes of the network receiving the port selection frame transmit frames to a specific node (PP), and specifies, as a main port for transmitting a frame, a port in which a frame is quickly received, out of a plurality of ports formed in the node itself.

In the example referring to FIG. 3, when the node A 1a transfers the port selection frame to other nodes formed in the ring network using the port 1 and the port 2, the node B (including the port 1 and the port 2) 2a receives the port selection frame transmitted from the node A (1) through the port 2 as soon as possible, and accordingly the node B (2a) stores the main port for the node A in the NPP table as the port 2.

As a detailed example, when the node A 1a as the source node transmits a frame to the node B 2a, the node B 2a transmits the frame through the port 2 of the node B 2a, that is, A route of a distance of one hop via one link formed between the node A 2a and the node A 2a and a route of receiving a frame through the port 1 of the node B 2a, The frame transmitted from the node A 1a serving as the source node through the path that is the distance of 5 hops for receiving the frame via the node E 5a, the node D 4a and the node C 3a, The frame transmitted from the node A 1a to the node B 2a is received first through the path using the port 2 of the node B 2a. Accordingly, when the node B 2a receives the port selection frame transmitted from the node A 1a and stores the main port for receiving the frame transmitted from the node A 1a in the NPP table, the node B 2a transmits, As the main port information.

At this time, when the node A 1a selects a port to transmit a data frame to the node B 2a, the node C 3a, and the node D 4a, the node A 1a transmits the data frame to the node B 2a, The node C 3a and the port D 4a through the ports of the node A 1a through the ports A and B so that the node B 2a can access the other nodes And selects it as a port suitable for a fast path for transmitting the frame.

Accordingly, when the node A transmits the port selection (PS) frame to the destination nodes, and receives the port selection frame from the other nodes, (Node primary port) table as shown in Table 1 of FIG.

Destination node's MAC address Major ports (PP number) Node B One Node C One Node D 2 Node E 2 Node F 2

The above table 1 is an NPP table which is port selection frame information set for the node A 1a in the network of the ring topology with reference to FIG. 3. As the port selection frame is received in the network structure, the node B 2a, Is applied by selecting the main ports reaching the node C 3a, the node D 4a, the node E 5a, and the node F 6a, respectively.

In this way, by specifying the main port information used when transmitting a frame from one node to another node, which is a destination node, as the NPP table, a frame is transmitted from the specific node to another node or a frame is transmitted to the destination node through the relay node , The frame is transmitted according to the designated port information with reference to the NPP table set in advance.

At this time, the NPP table can be changed or updated by port failure or network structure change.

Next, a port down (PD) frame among the five types of frames of the inherent code 14 is a frame including information as to whether a failure has occurred in a port formed in the corresponding node.

The port down (PD) frame is formed by including all of the ports in which at least one of the at least two ports formed in the corresponding node has occurred. For example, when a failure occurs only in the port 1 of the node D (4a), a port down (PD) frame in which the node first recognizing the failure includes whether or not the port 1 of the node D (4a) And the node D (4a) is disconnected from the network when a failure occurs in both the port 1 and the port 2 of the node D (4a), the node first recognizing the failure is disconnected from the network, And a port down frame including information on whether or not the port 2 is faulty as information.

The port up (PU) frame includes information indicating that the corresponding port of the failed node has been repaired from the failure.

At this time, the port selection (PS) frame, the port down (PD) frame, and the port up (PU) frame are formed in each node forming the network, , But at the same time, each node is broadcast to other nodes when frames (PS, PD, PU) are formed or updated.

Also, a network monitoring state (NMS) frame is formed at each node constituting the network, and includes node state information according to a non-physical defect other than a physical defect such as a port defect of the node, that is, a link defect, If no non-physical defect occurs, it is formed as information that the node is in a normal state and broadcasted to other nodes as soon as information is formed.

In one example, each node may generate a network monitoring status (NMS) frame at intervals of 100 ms, and if a new network monitoring status frame is not generated within 90 ms after a network monitoring status (NMS) The node that receives the network monitoring status (NMS) frame from the node and determines the failure state of the node may be the root node.

In one example, when each node broadcasts a frame (PS, PD, PU or NMS) that is information of the unique characteristic 14, each node transmits a MAC address of the corresponding node and frame information of the unique code 14 to broadcast The load consumption due to broadcasting a lot of information as shown in the frame 10 shown in FIG. 2 can be reduced.

 The network failure (NF) frame includes information indicating whether the network itself is defective or not, and is formed at a root node not formed at each node forming the network.

The root node may be a source node, and if a network monitoring status (NMS) frame broadcast by other nodes is not received for a certain period of time, it is determined that a failure has occurred in the network and the port selection (PS) Lt; / RTI > That is, as the root node broadcasts a network failure (NF) frame to all nodes, all nodes update their NPP tables.

As described above, the inherent code 14 included in the frame 10 of FIG. 2 includes information as a main port, a port failure, a port recovery, and a network normal state of each node as information. At this time, PS, PD, PU, and NMS) can broadcast its own frame at the node that generated the frame, and inform the other nodes of its state.

In addition, the unique code 14 included in the frame 10 of FIG. 2 includes a network failure (NF) frame, which is information indicating the network failure state generated at the root node, To generate new unique code 14 frames of other nodes in the network.

2, the frame 10 stores the actual data that the source node wants to transmit to the destination node in the payload 15 (step < RTI ID = 0.0 > And includes an error check code for determining the integrity of the frame 10 as a CRC (16) code.

As described with reference to Figs. 1 to 3, as each node of the present invention transmits the frame 10 including the unique code 14, when the source node transmits data to the destination node, It is possible to transmit data through the optimal path to the destination node using the information, thereby increasing the efficiency of the network.

As the source node constituting the ring network having the LPFR algorithm according to the present invention having this structure transmits the frame 10 of FIG. 2, it is possible to have at least one destination node that is the destination of the source node The relay node receives the frame 10 transmitted from the source node and confirms whether the MAC address 11 of the destination node on the frame 10 is its own node and completes receiving the received frame 10 at its node And transfers the frame 10 to the relay node or the destination node, which is another node, and performs the operation of delivering the frame 10 with reference to the NPP table generated by each node.

For example, in the case where the node receiving the frame 10 transmitted from the source node is a relay node other than the destination node (in this example, the source node is the node A 1a and the destination node is the node D The relay node is a relay node and the relay node is a relay node and the node B 2a identifies a part of the MAC address 11 of the destination node of the frame 10 transmitted from the source node 1a, Since the MAC address 11 of the node does not coincide with the MAC address of the own node, the received frame 10 is transmitted in the direction of the MAC address 11 of the destination node.

In transmitting the frame 10 received by the node B 2a as a relay node to the destination node, the NPP table 1 of Table 1 generated according to the PS frame received by the node B 2a from the node D (4a) Selects an optimal port for transmitting the frame 10 to the destination node, and transmits the frame 10 through the corresponding port.

When the node D 4a receives the frame 10 transmitted from the source node A 1a of the frame 10 and the node D 4a receives the MAC address 11 of the destination node of the frame 10, The MAC address of the destination node coincides with the MAC address of the node of the node 10, so that it is confirmed that the final destination of the received frame 10 is its own node, and finally the data loaded in the payload 15 is received , And also confirms the source node information that transmitted the frame 10 through the MAC address 12 of the source node.

In addition, the node B 2a as the relay node receives the frame 10, recognizes that it is not the final destination of the frame 10, and performs an operation of transferring the frame 10 to the destination node through the neighboring node , Even if the relay node transmits the frame 10 toward the destination node based on the NPP table, the frame 10 can not be delivered due to a link failure between the relay node and the neighboring node or a failure of the neighboring node .

At this time, when a link disconnection occurs between the neighbor node and the relay node, to which the relay node has transmitted the frame 10, that is, when a link failure occurs, the relay node can not transmit the frame 10 to the neighboring node. Thus, the relay node returns the frame 10 to be forwarded to the neighboring node back to the relay node.

Specifically, in the network of Fig. 3, which transfers the frame 10 from the source node node A 1a to the destination node D 4a via the relay node node B 2a and the node C 3a, A node C 3a as a relay node receives a frame received from the node C 3a and the node B 2a as a relay node when a failure occurs in a link between the node C 3a as a relay node and the node D 4a as a destination node. 10 to the node B 2a and transmits it.

At this time, the node C (3a) which has detected the link failure returns the inherent code (14) portion of the frame 10 to be transmitted back to the node C (10) 3a can recognize that a failure has occurred in the link between the node C 3a and the node D 4a or the port connecting the node C 3a to the node D 4a.

Further, as the port connecting the node C 3a to the node D 4a is disabled, the node C 3a updates the port selection (PS) frame and the NPP table for the other nodes of the node C 3a And broadcasts the updated information.

Therefore, the node B 2a receives the frame 10 already transmitted to the node C 3a from the node C 3a and transmits the frame 10 back to the node C 3a via the inherent code of the received frame 10, D 4a and transmits the frame 10 to be transmitted to the destination node to the node A 1a through the direction opposite to the transmission direction of the first frame 10.

At this time, even if the node B 2a does not recognize the port down (PD) frame in the inherent code 14 of the frame 10 received back from the node C 3a, When the frame 10 which has already been transmitted to the node B 3a through the node B 2a performs an operation of passing through the corresponding node, that is, the node B 2a twice, So that it can be recognized that it has been received back.

In such an example, the neighbor node to which the relay node delivers the frame 10 may be another relay node located between the source node and the destination node, or may be the destination node, and when the relay node delivers the frame 10 back, The receiving neighbor node may be another relay node located between the source node and the relay node, or may be a source node, but is not limited thereto.

As described above with reference to FIG. 3, in a ring network having an LPFR algorithm according to an embodiment of the present invention, each node transmits a frame 10 from a source node to a destination node, (10) is sent back in the direction opposite to the node where the failure occurred, the transmission path to the destination node is changed, a port down (PD) is generated at the node where the failure occurs, and a port selection And broadcasts it, updates the NPP table, informs the network of the link failure, and prevents the use of the corresponding node. Thus, the reliability of the network can be improved.

At this time, when a problem on the transmission path occurs, the frame 10 is directly retransmitted in the opposite direction, so that even if a failure occurs in the network, the node is immediately switched to improve the data transmission reliability of the network, Thereby reducing data loss due to port switching. Reducing the data loss in this manner has the effect of reducing the data transmission time required to retransmit the lost data.

In the ring network having the LPFR algorithm according to an embodiment of the present invention, a frame 10 transmitted from the source node to the destination node through one direction returns to the source node and transmits the frame 10 in the opposite direction. The source node does not transmit any frame 10 through the corresponding node or link until the failed link or node is recovered and transmits the frame 10 to the destination node And also deletes a copy of the frame 10 to be deleted.

This can prevent a loop that may occur on the ring network due to a link or a node defect, thereby improving the performance of the network.

The operation flow of the ring network having the LPFR algorithm according to an embodiment of the present invention having such a structure and characteristics will be described with reference to FIGS. 4 and 5. FIG.

In the structure of Fig. 4, which is a ring network with an LPFR algorithm according to an embodiment of the present invention, node C 3b is the source node and node F 6b is the destination node and node A 1b and node F 6b ) And between the node E (5b) and the node F (6b), respectively.

5, the node C 3b transmits a frame to the node F 6b according to a step S110 of the source node transmitting the frame to the destination node.

At this time, the node C (3b) has already set up the NPP table, and the node C (3b) has already set up the NPP table, and according to the port selection (PS) frame included also in the unique code part of the frame to be transmitted to the node F F 6b and transfers the frame. In this embodiment, since the port 2 is specified as the optimal port for the node F (6b) in the NPP table of the node C (3b), the port 2 To the node F (6b) along the counterclockwise direction.

Next, according to the step S120 of moving the frame through the first direction (counterclockwise direction) from the source node to the destination node and transmitting the frame to the first neighboring node adjacent to the source node, the node C (3b) The frame to be transmitted to the node F (6b) is transmitted to the node B (2b) adjacent to the node C (3b).

4, there is a first neighbor node because there is a relay node between the node C 3b and the node F 6b, but in another embodiment, between the node C 3b and the node F 6b The node C 3b can directly transmit the frame to the node F 6b and perform the next step Q100 without performing the second step S120.

4, a node B (2b), which is a relay node located between the node C (3b) as the source node and the node F (6b) as the destination node, And node A (1b) correspond to the first neighbor node.

According to the above steps S110 and S120, the frame transmitted from the source node C 3b to the destination node F 6b includes the first neighboring node B 2b and the node A 1b .

At this time, however, when the node C 3b transmits the frame to the node F 6b along the first direction, the relay nodes located between the node C 3b and the node F 6b and the node F 6b ), A node failure or a link failure connecting them may occur, and each node senses this (Q100).

If a failure is detected such as a link disconnection between the node A 1b and the node F 6b in the step Q100 of detecting a node or link failure during frame transmission in the first direction ), The frame that the small node has transmitted to the destination node through the second direction opposite to the first direction is returned to the direction of the source node.

More specifically, the frame transmitted from the node C 3b is transmitted between the node A 1b and the node F 6b while being transmitted to the node F 6b through the node B 2b and the node A 1b The node A 1b senses the failure of the connecting link or the failure of the port 2 of the node A 1b and the node A 1b detects the frame which is being transmitted to the node F 6b as the opposite direction of the first direction Back to the node C 3b along two directions, that is, clockwise direction (S210).

Then, the node A (1b) that has detected the failure generates a port down (PD) frame and broadcasts it to the network, thereby detecting a failure state of the port 2 of the node A 1b or a failure state of the node A (1b) (S220), and updates the NPP table of the failed node A (1b) (S230).

4, the main port for the node F 6b is designated as the port 2 in the NPP table of the node A 1b, and accordingly the frame transmitted from the node C 3b to the node F 6b The node A 1b attempts to perform a process of being transmitted to the node F 6b through the port 2 of the node A 1b. However, as a failure occurs in the port 2 of the node A 1b, F (6b) is changed to port 1 by performing the NPP table update.

The node C (3b), which is the source node receiving the frame back from the step 210, transmits the frame to the destination node along the second direction opposite to the first direction in which the first frame was transmitted to the destination node, If a second neighboring node is located between the node C 3b serving as a node and the node F 6b serving as the destination node, the frame is transmitted to the destination node through the second neighboring node S240.

Accordingly, the node C 3b transmits the frame to the node F 6b through the second neighboring node D 4b and the node E 5b along the second direction, that is, the clockwise direction.

At this time, a step Q200 of detecting a node or link failure in the frame transmission process in the second direction is performed, and a link failure between the node E 5b and the node F 6b or a link failure between the node E 5b and the port F , The frame transmitted from the node C (3b) to the node F (6b) in the second direction is detected again as the first direction which is the opposite direction of the second direction Direction to the node C 3b (S410).

Then, the node E (5b) which has detected a link failure between the node E (5b) and the node F (6b) or a port 1 failure of the node E (5b) generates a port down (PD) frame and broadcasts it to the network A step S420 of notifying the failure state is performed, and the NPP table of the node E 5b in which the failure occurs is updated (S430).

That is, in the network shown in Fig. 4, the main port for the node F (6b) is designated as the port 1 in the NPP table of the node E (5b), and accordingly, the frame transmitted from the node C (3b) The node E 5b attempts to perform the process of transferring to the node F 6b through the port 1 of the node E 5b. However, as a failure occurs in the port 1 of the node E 5b, F (6b) is changed to the port 2 in the NPP table update.

Since the source node C 3b receives the frame to be transmitted to the destination node through the first neighbor node in step S210 and receives the frame to be transmitted to the destination node through the second neighbor node in step S410, The node C 3b as the source node judges that the frame can not be transmitted to the node F 6b which is the destination node in the first direction or the second direction and stops the frame transmission at step S440.

The node C 3b, the node B 2b and the node D 4b receive a port down (PD) frame broadcast by the node A 1b and a node E 5b, respectively, However, it is necessary to detect the recovery of a node that has failed according to a port-up (PU) frame generated due to the recovery of the failed node from the failure, and to reflect the failure in the transmission path formation .

In addition, the nodes constituting the network may respectively generate and broadcast a network monitoring state (NMS) frame to notify each state to the network, and monitor the failure state of each node constituting the network at the root node. A network failure (NF) frame is generated and broadcasted in an efficient manner.

However, in the flowchart of FIG. 5, when a node or link failure is not detected in the course of transmitting a frame to the destination node first in the first direction at the source node (arrow NO direction in Q100 of FIG. 5) The frame is transmitted to the destination node F 6b through the node B 2b and the node A 1b so that the node F 6b takes the data contained in the payload 15 portion of the frame.

In addition, when a frame transmitted in the first direction at the source node is returned by the node or the link failure and the frame is transmitted to the destination node through the second direction, when no node or link failure is detected , The frame is transmitted to the destination node F (6b) through the node D (4b) and the node E (5b) which are the second neighbor nodes, and the node F (6b) And the data contained in the portion 15 is taken.

From the sequence of operations performed in this order, in a ring network having an LPFR algorithm according to an embodiment of the present invention, a frame transmitted from a source node to a destination node transmits a frame through an optimal port according to a set NPP table And detecting a failure in the node or the link and switching the node to switch the transmission path, so that when a failure occurs in the network, the frame can be quickly transmitted through the alternative path, thereby improving the performance of the network.

In addition, a port down (PD) frame of a node in which a failure occurs is generated, and the NPP table is updated and broadcast, thereby transmitting frames through an optimal transmission path in the network, thereby improving the performance of the network.

In addition, when the source node receives a frame transmitted to the destination node from both directions, it determines that the frame transmission to the destination node through both directions is impossible and stops the frame transmission, It is possible to prevent a loop due to the frame transmission of the frame.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

1: source node 2: destination node
10: Frame 11: MAC address of destination node
12: Mac address of the source node 13: Serial number
14: Unique code 15: payload
16: CRC

Claims (10)

A source node having at least two ports to transmit a data frame to a destination node via any one of the at least two ports,
A destination node connected directly to the source node or connected through a relay node to receive the data frame transmitted from the source node,
, ≪ / RTI &
Wherein the source node specifies port information on which of the at least two ports to transmit the data frame to the destination node as a node primary port (NPP)
Wherein if a primary port, which is a port used to transmit a data frame to the destination node, is determined to have failed, transmitting the data frame to the destination node through a port other than the primary port of the source node, And the node main port is changed in accordance with the transmission path switching. 2. The ring network as claimed in claim 1, The method according to claim 1,
Further comprising at least one relay node located between the source node and the destination node and relaying transmission of the data frame from the source node to the destination node,
Wherein the at least one relay node transmits a failure to the destination node when a failure occurs in a link between the source node and the relay node or a port from the at least one relay node to the destination node, To send back said data frame to said source node,
Wherein the at least one relay node has at least two ports and transmits port information on which port of at least two ports of the relay node to transmit the data frame to the destination node, wherein the port selection frame and the node main port are designated as port disconnection between the source node and the relay node or when a failure occurs in the port from the at least one relay node to the destination node, And changing the node main port. 3. The method according to claim 1 or 2,
Wherein the source node or the at least one relay node broadcasts the port selection frame to the source node or the network to which the at least one relay node belongs. 3. The method according to claim 1 or 2,
Wherein the source node or the at least one relay node has a table for specifying a node main port (NPP) for each node except for the node itself in a network to which the node belongs,
The NPP table is changed by switching the transmission path of the node as a failure occurs in the source node or the at least one relay node,
Wherein the source node or the at least one relay node broadcasts the changed NPP table when a failure occurs in the port of the source node or the relay node. 3. The method of claim 2,
If the at least one relay node has transmitted the data frame back to the source node, the source node transmits the data frame to the destination node via another transmission path according to the changed node main port,
RTI ID = 0.0 > 1, < / RTI > wherein the different transmission path may comprise at least one relay node. 6. The method of claim 5,
The source node transmits the data frame to the destination node through the another transmission path but a port failure or a link disconnection occurs in the other transmission path to return the data frame to the source node in the other transmission path Wherein the source node stops transmitting the data frame to the destination node when the source node receives the data frame back through both directions. 5. The method of claim 4,
The source node or the at least one relay node generates a port down (PD) frame and broadcasts the changed NPP table as a failure occurs in the source node or the at least one relay node, Wherein the source node or other nodes belonging to the network to which the relay node belongs confirm the failure status through the port down frame. 3. The method according to claim 1 or 2,
When a failure occurs in the source node or the at least one relay node, broadcasts a port up (PU) frame as a failure is recovered, and the source node or other nodes belonging to the network to which the relay node belongs And the node recovery state is confirmed through the port up frame. 3. The method according to claim 1 or 2,
All of the nodes other than the source node among all the nodes belonging to the source node or the network to which the relay node belongs transmit a network monitoring status (NMS) frame notifying whether the node is in the network normal state to the source node The root node receives the network monitoring status frame to determine a network failure status. If the network failure status is determined, the network node generates a network failure (NF) frame and broadcasts the frame to the nodes included in the network And controlling the nodes included in the network to be restarted. 10. The method of claim 9,
Wherein the source node or all nodes belonging to the network to which the relay node belongs periodically transmit the network monitoring status frame to the source node,
Wherein the source node is a root node and generates the network failure frame if it fails to receive the network monitoring status frame within the period from the source node or all nodes belonging to the network to which the relay node belongs. Lt; / RTI >

Images