WO2015170793A1

WO2015170793A1 - Method for reducing network traffic using dual virtual path algorithm

Info

Publication number: WO2015170793A1
Application number: PCT/KR2014/004959
Authority: WO
Inventors: 이종명; 알라위 나자이프사드
Original assignee: 명지대학교 산학협력단
Priority date: 2014-05-09
Filing date: 2014-06-03
Publication date: 2015-11-12
Also published as: KR101566314B1

Abstract

The present invention relates to a method for reducing traffic in a network of various structures and, particularly, to a method for reducing traffic in an Ethernet network using a High-availability Seamless Redundancy (HSR) standard, the method comprising the steps of: broadcast-transmitting, by each terminal node, a declaration frame and generating, by each first node, a neighboring table including information on a terminal node within a network; establishing dual virtual paths for each first and second terminal node pair; and transmitting a data frame from a source terminal node to a destination terminal node via one path of the dual virtual paths. The present invention reduces unnecessary duplicate unicast traffic within a network, thereby being capable of improving the performance of the network.

Description

Network Traffic Reduction Method Using Dual Virtual Path Algorithm

The present invention relates to a method for reducing traffic in various structures of a network, particularly a method for reducing traffic in an Ethernet network using a high availability seamless redundancy (HSR) standard, and more particularly, to a dual virtual path (DVP). The present invention relates to a network traffic reduction method that can improve the performance of an HSR network by reducing the unnecessary redundant unicast traffic in an HSR closed loop network.

Currently, there is a limited method for properly reducing traffic in a network using a redundancy protocol and the like, and an efficient method for reducing traffic in a network using a high availability seamless redundancy (HSR) standard. A method of reducing traffic in a network using such an HSR standard is disclosed in Korean Patent Laid-Open Publication No. 0-2013-0095154 (hereinafter referred to as 'prior document').

The network traffic reduction method according to the prior art can control the node to receive only one copy of the frame, thereby eliminating unnecessary transmission and reception of the frame copy, thereby reducing the traffic compared to the previous network system.

However, the network traffic reduction method according to the prior art has a limitation in that it can reduce the traffic only for the network forwarding the frame copy by broadcasting or multicasting.

[Preceding technical literature]

[Patent Documents]

Korean Patent Publication No. 10-2013-0095154 (published: 2013.08.27., Title of the invention: network traffic reduction method, claim 1)

The present invention provides a network traffic reduction method for improving the performance of an HSR network by reducing unnecessary redundant unicast traffic in an HSR closed loop network in a network using the HSR standard.

In order to achieve the above object, in a network traffic reduction method using a dual virtual path algorithm according to an embodiment of the present invention, each terminal node broadcasts a declaration frame, and each first node is based on the declaration frame. Generating a neighbor table containing information about terminal nodes in a network, thereby declaring a terminal node, for each first and second terminal node pair, the first terminal node referring to its neighbor table for the By unicast transmitting a path selection frame to a second terminal node, wherein each second node generates a prepass table that includes path information from the first terminal node to a second terminal node based on the path selection frame, Establishing a dual virtual path between the first and second terminal nodes; And transmitting a data frame from a source terminal node to a destination terminal node through at least one of the virtual paths.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, in the step of declaring the terminal node, the first node is not the source node of the received declaration frame, but the received declaration frame identifies itself. If it has not already passed, the received declaration frame is read and the MAC address of the source node of the received declaration frame and the sequence number of the received declaration frame are added to the neighbor table.

In the method of reducing network traffic using the dual virtual path algorithm according to the present invention, the first node may delete the received declaration frame when the source node of the received declaration frame is itself.

In the method of reducing network traffic using the dual virtual path algorithm according to the present invention, the first node may determine that the received declaration frame has already passed through itself, and the MAC address of the source node of the received declaration frame and the received node. At least one of the cases in which the sequence number of the declaration frame is indicated in the neighbor table is characterized in that the received declaration frame is processed according to standard HSR rules.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, in the establishing of the dual virtual path, the second terminal node is a terminal node including a MAC address in a neighbor table of the first terminal node. It is characterized by.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, in the step of establishing the dual virtual path, when the second node is a terminal node and not a source node and a destination node of the received path selection frame, the A second node forwards the received path selection frame to a port different from the received port, and deletes the received path selection frame if it has already forwarded the received path selection frame to a different port than the previously received port. It is characterized by.

In the network traffic reduction method using the dual virtual path algorithm according to the present invention, in the step of establishing the dual virtual path, when the second node is a terminal node and the destination node of the received path selection frame, the received path selection Receive another copy of the received path selection frame from a port different from the port receiving the frame, generate or update a prepass table with information about the received path selection frame, and source node of the received path selection frame. And replying the path confirmation frame.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, the information about the received path selection frame may include an input port number at which the received path selection frame is received, a source and a destination node of the received path selection frame. And an identification tag of the quadbox node attached to the MAC address and the received path selection frame.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, in the step of establishing the dual virtual path, when the second node is a quadbox node, transmitting from the first terminal node to the second terminal node. Generate or update a prepass table with information about a path selection frame that has reached the second node earlier among the path selection frames, attach an identification tag of the second node to the reached path selection frame, and reach the It is characterized by forwarding both the path selection frame and the duplicated path selection frame that have arrived by copying one path selection frame.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, the information about the reached path selection frame includes the sequence number of the reached path selection frame, the MAC address of the source node and the destination node of the reached path selection frame. And an identification tag of the quadbox node attached to the reached path selection frame.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, when the second node is a quadbox node, after a predetermined second step time elapses, the second node is included in the prepass table of the second node. Among the terminal node pairs, information about a terminal node pair in which a path confirmation frame does not pass through the second node is deleted from the free path table of the second node.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, when the second node is a quadbox node, after the predetermined second step time elapses, the second node may be configured as a source in the free pass table. And generating a final route table inverting the MAC addresses of the destination nodes.

In the method of reducing network traffic using the dual virtual path algorithm according to the present invention, in the establishing of the dual virtual path, between the first and second terminal nodes received by at least one of the first and second terminal nodes. The identification tag included in the transmitted path selection frames is compared to determine whether or not a common node exists between the dual virtual paths.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, the identifying terminal node is a blocking node, when the common node exists, the blocking node in connection with the transmission between the first and second terminal node. Requesting to block a port that connects to the network, requesting to reestablish a path between the first and second terminal nodes, and reestablishing a path where no common node exists between the first and second terminal nodes. After that, the blocking node is requested to release the block.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, in the transmitting of the data frame, the source terminal node copies the data frame and transmits the data frame to the dual virtual path with the destination terminal node, respectively. It is characterized by.

In the method of reducing network traffic using the dual virtual path algorithm according to the present invention, in the step of transmitting the data frame, when the data frame reaches the terminal node, the terminal node reached by the data frame is unicoded. At least one method of receiving, discarding, deleting, and forwarding the data frame based on at least one of whether the frame is a cast frame and whether the terminal node at which the data frame arrives is the destination terminal node. do.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, in the step of transmitting the data frame, when the data frame reaches the quadbox node, the quadbox node reached by the data frame is the data frame. Determining whether to process the data frame according to standard HSR rules or forward the data frame to an appropriate output port based on whether it is a unicast frame and the final path table of the quadbox node reached. It is characterized by.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, in the step of transmitting the data frame, when the data frame is transmitted before the step of establishing the dual virtual path is completed, each node is a standard. The data frame is processed according to an HSR rule.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, the first terminal node periodically copies a path health confirmation frame and transmits copies thereof to the second terminal node through one virtual path, And if the second terminal node receives a copy of the transmitted path health confirmation frame, monitoring the virtual path by returning a path health confirmation frame to the first terminal node.

In the method for reducing network traffic using the dual virtual path algorithm according to the present invention, in the monitoring of the virtual path, when the first terminal node receives all copies of the path health confirmation acknowledgment frame, it is attached to the copies. It is characterized in that all the node identifier tags are attached in the same order according to the free path table of the first terminal node, and if they are not attached in the same order, the one virtual path is reestablished.

In the method of reducing network traffic using the dual virtual path algorithm according to the present invention, the first terminal node unicasts a repath selection frame to the second terminal node, and each quadbox node duplicates the repath selection frame. Forwarding copies to a next node, and when the second terminal node receives the repath selection frame, reestablishing the virtual path by sending the path selection frame to the first terminal node. It features.

According to the present invention, the performance of the network can be improved by reducing unnecessary redundant unicast traffic in the network.

1 is a diagram illustrating a standard HSR protocol and a dual virtual path special frame according to an embodiment of the present invention.

2 is a flowchart illustrating the operation of declaring a terminal node according to an embodiment of the present invention.

3 is a flowchart illustrating an operation of generating a neighbor table in a step of declaring a terminal node according to an embodiment of the present invention.

4 is a flowchart illustrating an operation of a terminal node in establishing a dual virtual path according to an embodiment of the present invention.

5 is a flowchart illustrating an operation of a quadbox node in establishing a dual virtual path according to an embodiment of the present invention.

6 is a diagram illustrating an example of a network in which a common node problem occurs in establishing a dual virtual path according to an embodiment of the present invention.

7 is a flowchart illustrating an operation of a terminal node in a step of transmitting a data frame according to an embodiment of the present invention.

8 is a flowchart illustrating an operation of a quadbox node in a step of transmitting a data frame according to an embodiment of the present invention.

9 is a diagram illustrating an example of an HSR network according to an embodiment of the present invention.

10 is a diagram illustrating frame transmission at each example node under the standard HSR protocol as a result of transmitting a unicast frame from the first example node to the second example node according to an embodiment of the present invention.

FIG. 11 is a diagram illustrating frame transmission at each example node under the standard HSR protocol as a result of transmitting a unicast frame from the third example node to the first example node according to an embodiment of the present invention.

12 is a diagram illustrating frame transmission at each example node under the standard HSR protocol as a result of transmitting a unicast frame from the first example node to the second example node in a node failure case according to an embodiment of the present invention.

FIG. 13 is a diagram illustrating frame transmission at each example node under the standard HSR protocol as a result of transmitting a unicast frame from the third example node to the first example node in a node failure case according to an embodiment of the present invention.

14 is a graph comparing network traffic and discarded traffic between an HSR standard and a DVP algorithm in a faultless case according to an embodiment of the present invention.

15 is a graph comparing network traffic and discarded traffic between the HSR standard and DVP algorithm of a link failure case according to an embodiment of the present invention.

16 is a graph comparing network traffic and discarded traffic between the HSR standard and DVP algorithm in a node failure case according to an embodiment of the present invention.

[Description of the code]

1: first example node 2: second example node

3: 3rd example node 4: 4th example node

5: 5th example node 6: 6th example node

7: 7th example node 8: 8th example node

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Network traffic reduction method of the present invention relates to a method for reducing the traffic (traffic, load) of the network when transmitting and receiving a frame or frame copy (Frame Copy) in a variety of networks, in particular the traffic reduction when sending and receiving a frame copy Suggest a method. As the network of the present invention, various networks such as Ethernet may be used.

Frame copying is used for redundancy protocols, redundancy systems and the like. For example, in the case of redundancy of nodes, that is, in the case of connecting the nodes through two channels, frame copies are transmitted in advance to the nodes via the channels. By transmitting the frame copies in advance, when a failure occurs in one of the channels, it is possible to quickly restore the connection between the nodes through another channel that does not fail. That is, the system can use frame copy to reduce channel recovery time between nodes.

The present invention can be applied to various networks, and in particular, to a high availability seamless redundancy (HSR) standard network. HSR is a standard redundancy protocol standardized by the IEC62439-3 standard and is applied to redundant systems. In the HSR protocol, each node duplicates a frame and transmits the same frame through two ports to prepare for failure. Even if one channel fails, the duplicated frame is always transmitted to the other channel so that the failure recovery time is zero. can do.

The HSR network always duplicates each unicast frame transmitted on each quadbox node type available within the network and randomly forwards these frames to the destination, thus allowing many frame copies to circulate on the network. While other circular frame copies are deleted and removed from the network immediately after going through the same node twice in the same direction, the destination node finally receives only two of these frames, takes the fastest, and discards the second. .

The DVP algorithm of the present invention solves this problem by establishing two virtual paths between a pair of two terminal nodes. Since quadbox nodes are used only for interconnection purposes and do not have any other connected end users, a virtual full mesh network is established between all terminal nodes except quadbox nodes. The established virtual paths go through quadbox nodes. However, since the virtual path does not replicate and random forward at each quadbox node as in the standard HSR protocol, all transmitted unicast frames are forwarded from the source node to the destination node along the virtual path, and the number of frame copies transmitted remains constant. do. Thus, the DVP algorithm can reduce total network traffic and improve network performance.

Hereinafter, an embodiment of a network traffic reduction method using the dual virtual path algorithm of the present invention will be described with reference to the accompanying drawings.

The DVP algorithm proposed in the present invention uses special frames called dual virtual path special frames having a purpose and a task to be performed, and the dual virtual path special frames have an announce (ann) frame and a path selection according to their role. Selection (PaS) frame, Path Confirmed (PAC) frame, Path Health Checking (PHC) frame, Request Block (ReB) frame, Open Block (OB) frame, Path health Ackowleged Path Health Checking (ACK PHC) frame, Acknowledgment Request Block (ACK ReB) frame, Acknowledged Open Block (ACK OB) frame, Re-Path Selection (RePas) There is a frame.

When dual virtual paths (DVP) are in operation, in order to allow HSR nodes to distinguish DVP special frames, they have a unique code for each DVP special frame in the payload of the standard HSR frame. Insert a new field. This new field is called the DVP Frame Type (DTF).

As shown in FIG. 1, the size of the DTF field is 2 octets. The reason for positioning the DFT field in the payload is to keep the entire DVP special frame at the standard HSR size. However, in order to distinguish the DVP special frame with each unique DFT code from standard HSR frames, it is necessary to set a flag or code in the header of each special DVP frame. Otherwise, HSR nodes will consider all received frames as standard HSR frames and may apply standard rules. Nevertheless, if the node can recognize that the frame is a special DVP frame, it can read the DFT field and take appropriate action according to the DVP algorithm rules. For this purpose, we use one of the reservation codes of the path identifier field located inside the HSR standard frame header. Here, the reservation code means a code having a fixed specific meaning. Code 1100 represents a special DVP frame, otherwise the node considers the received frame as a standard HSR frame. The DVP algorithm continues to use the standard HSR protocol during the setup procedure until it completes all the setup processes, that is, generating the neighbors (Ne) table and establishing the DVP. Nevertheless, if a data frame is sent from one node to another during the DVP setup procedure, each received node will check the path identifier field for the received frame and if it is equal to 1100 or Check if it is a different value. If the path identifier field is 1100, then it is a special DVP frame, and after reading the DFT field value, perform the appropriate activity. If the path identifier field is not 1100, it is a standard HSR frame and standard HSR transmission rules apply. Therefore, no frames are lost during the DVP setup procedure.

In the network traffic reduction method using the dual virtual path algorithm according to an embodiment of the present invention, each terminal node broadcasts an Ann frame, and each first node includes information about terminal nodes in the network based on the Ann frame. Declaring a terminal node by creating a Ne table, for each first and second terminal node pair, the first terminal node unicasts a PaS frame to the second terminal node with reference to its Ne table, At least one of establishing a DVP between the first and second terminal nodes by generating a PrP table that includes path information from the first terminal node to the second terminal node based on the PaS frame. And transmitting the data frame from the source terminal node to the destination terminal node via the path of.

As shown in Fig. 2, in the step of declaring a terminal node, each terminal node declares itself by broadcasting a kind of special DVP frame called an announcement (ann) frame. Frame copies of the Ann frame propagate through the network until each copy is returned to the source node or passed through the same node twice in the same direction and deleted and removed from the network.

Once the Ann frames are transmitted and start to propagate in the network, all nodes, including the quadbox node type, ie each first node, read each passing Ann frame and create the Ne table. At this time, the Ne table includes the sequence number of each read Ann frame and the MAC address of the source node.

3 is a flowchart illustrating an operation of generating an Ne table according to an embodiment of the present invention.

As shown in FIG. 3, in the step of declaring a terminal node, each first node selects a received Ann frame when the source node of the received Ann frame is not itself and the received Ann frame does not pass through itself. The MAC address of the source node of the read Ann frame and the sequence number of the received Ann frame may be added to the Ne table.

At this time, if the source node of the received Ann frame is itself, the first node may delete the received Ann frame. Further, the first node receives at least one of when the received Ann frame has already passed through it, and when the MAC address of the source node of the received Ann frame and the sequence number of the Ann frame are displayed in the neighbor table. One Ann frame can be processed according to standard HSR rules.

Therefore, the Ann frame is forwarded according to standard HSR rules and propagated along the network, so that information about the Ann frame for all terminal nodes is included in each Ne table, so that each node includes information about terminal nodes in the network. You can create Ne tables.

When the creation of the Ne table at each node is complete, each node will know from its Ne table how many terminal nodes are available in the network and what their MAC addresses are. As a result, it is then possible for all terminal nodes to send unicast frames to each other, instead of broadcasting. The duration required to complete all tasks of the phase of declaring a terminal node and move to the second phase is defined as the Duration Time of the First Phase (DTFP), approximately 128 milliseconds (msec). Can be estimated as DTFP can be approximated at 150 msec to create margins including generation of Ne tables and transmission delay of wires.

Subsequently, in the method of reducing network traffic using the DVP algorithm according to an embodiment of the present invention, for all the first and second terminal node pairs, the first terminal node refers to its Ne table to the second terminal node as a PaS. Transmits a unicast frame, and every node in the network, i.e. each second node, generates a PrP table containing path information from the first terminal node to the second terminal node based on the PaS frame, thereby Establish DVP between terminal nodes.

This allows point-to-point communication between terminal nodes via DVP without propagating data frames over the network as in the HSR protocol. The establishment of DVP is performed by informing quadbox nodes how to forward or guide the frame to the source or destination terminal nodes of the received frame without copying and random forwarding of the received frame.

At this time, in the step of establishing the DVP, the second terminal node may be a terminal node that includes the MAC address in the Ne table of the first terminal node. That is, as described above, since the Ne table of each node includes information about each terminal node, each of the other terminal nodes whose PaS frame, which is a special DVP unicast frame, is specified in its Ne table. By transmitting to the network, DVP can be established for all terminal node pairs.

4 is a flowchart illustrating the operation of a terminal node in the step of establishing a DVP according to an embodiment of the present invention.

As shown in FIG. 4, in the step of establishing DVP, if the second node is a terminal node and is not a source node and a destination node of the received PaS frame, the second node is different from the port receiving the PaS frame received by the second node. If you forward to a port, but already forwarded the PaS frame to a different port than the previously received port, you can delete the received PaS frame.

That is, each terminal node that receives a PaS frame belonging to the connection pair, rather than part of the connection pair, may forward or delete it from another port if the frame was previously forwarded in the same direction.

Also, in the step of establishing DVP, when the second node is a terminal node and a destination node of the received PaS frame, another copy of the same PaS frame is received from a port different from the port receiving the received PaS frame, that is, Receive a copy of the received PaS frame in both directions, create or update the PrP table with information about the received PaS frame, and return a Path Confirmed (PaC) frame to the source node of the received PaS frame. have.

As will be described later, quadbox nodes forward the received PaS frame copy to the destination terminal node. In this process, it is possible to know which port can go to the source node of the received PaS frame, but the destination node of the received PaS frame is known. It does not know which port it can go through. Thus, to establish a bidirectional virtual path between the source and destination nodes of each connection pair, the destination terminal node responds with a PaC frame to the source terminal node. Each copy of the PaC frame moves through one of the established DVPs, and in this process, each quadbox node can know which port can be connected to the destination node of the connection pair. Thus, all quadbox nodes that have undergone PaC frame copies will be able to forward frames for both directions of the connection pair.

In this case, the received PaS frame information includes the input port number of the received PaS frame, the MAC address of the source and destination nodes of the received PaS frame, and an identification tag of the quadbox node attached to the PaS frame. , ID Tag).

In addition, each terminal node may receive a total of two transmitted PaS frame copies, one in each direction, and create or update its own PrP table by reading information on the PaS frame from the received frame copy.

The PrP table of the terminal nodes contains a list of all identification tags that have been attached to all received PaS frames, but the PrP tables of quadbox nodes do not contain a list of such identification tags. These tags are used to ensure that there are no common nodes between the DVPs of each connection pair, that is, the two virtual paths that make up the DVP are completely independent and separate.

5 is a flowchart illustrating the operation of a quadbox node in the step of establishing a DVP according to an embodiment of the present invention.

As shown in FIG. 5, when the second node is a quadbox node, the PrP table includes information about a PaS frame that reaches the second node most quickly among path selection frames transmitted from the first terminal node to the second terminal node. May be generated or updated, the identification tag of the second node is attached to the reached PaS frame, and the reached PaS frame and the duplicated PaS frame may be forwarded by replicating the reached PaS frame.

In this case, the information about the PaS frame reached may include the sequence number of the PaS frame reached, the MAC address of the source and destination nodes of the PaS frame reached, and the identification tag of the quadbox node attached to the PaS frame. .

That is, as soon as a PaS frame is sent for every terminal node connection pair, so as to start randomly passing from node to node towards another corresponding terminal node in the connection pair, each quadbox node has its identification tag in the PaS frame payload. Will be attached.

Subsequently, when the second node is a quadbox node, after a preset duration time for the second phase (DTSP) has elapsed, a PaC frame is generated from a pair of terminal nodes included in the PrP table of the second node. Information about a terminal node pair not to pass through the second node may be deleted from the PrP table of the second node.

Nodes that will not pass through PaC frames are not part of the virtual path, and the size of the PrP table can be kept small by deleting information about the pair of terminal nodes where the PaC frames will not pass through the second node, and contain unnecessary entries. You can do it.

In addition, when the second node is a quadbox node, after a predetermined DTSP time elapses, the second node flips MAC addresses of the source and destination nodes in the PrP table to each other (Final Path Table, FP). Table) can be created.

The FP table is a table used for forwarding frames received in both directions and may be inferred from the PrP table. The FP table is created by taking the source and destination MAC address columns from the PrP table and flipping their contents. The FP table will also use the input port column as the output port column. The FP table no longer needs the sequence number column since the role of the sequence number column in the process has ended. Process generation of the FP table can begin immediately after the expiration of the DTSP time, which is the point before the DVP establishment step ends and before moving to the step of transmitting the data frame.

The value of DTSP time is Duration Time for Paths Re-establishment Prodecure in Duration Time for the Second Phase under a Normal Situation (DTSPn). , DTPR) and Duration Time of the Common Node Problem (DTCN). In general, DTSPn is estimated to be 256msec, DTRP is 768msec, and DTCN is 1792msec. Therefore, DTSPn can be estimated to be 2815msec. In order to secure a margin, the DTSP may be assumed to be about 3000 msec.

In establishing the DVP, there is no common node between the DVPs by comparing the identification tags included in the PaS frames transmitted between the first and second terminal nodes received by at least one of the first and second terminal nodes. You can check whether or not.

DVPs are set up to be completely separate from each other, because if one of the DVP paths does not work, the other must not be affected. Therefore, the terminal node of each connection pair can confirm that these requirements are met when generating the PrP table.

Referring to the example illustrated in FIG. 6, for example, at least one of the source node A and the destination node M may determine whether a common node exists between the DVP between A and M.

At this time, a checking node node for checking whether a common node exists or not compares identification tags of a PaS frame copy so that a common node does not exist between paths of each PaS frame copy except for a source node and a destination node. Check that it is not.

If there is a common node, the identifying terminal node may select a second path and identify a node called a blocking (BLO) node located after the common node closest to it. For example, in the example of FIG. 6, F is a common node and G is a BLO node.

The confirming terminal node requests the blocking node to block a port that connects to the common node in connection with the transmission between the first and second terminal nodes if a common node exists, and between the first and second terminal nodes. It may request to reestablish the path of, and may request that the blocking node release the block after the path where the common node does not exist between the first and second terminal nodes is reestablished.

At this point, the acknowledgment terminal node can send a ReB frame that is a reliable DVP unicast frame to the BLO node, which connects the BLO node and the common node to deliver all PaS frames belonging to the same connection pair. You can tell the BLO node to logically block the port.

A BLO node can identify which port is connected to the common node from all its ports in order to search its PrP table and forward the problematic pair of connections, and block that port. Thereafter, the BLO node may transmit an ACK ReB frame to the confirming terminal node.

The acknowledgment terminal node may send a RePas frame to the corresponding terminal node of the same connection pair to retransmit the PaS frame, i.e. reestablish a new path. When the corresponding terminal node receives the RePas frame, it immediately sends a PaS frame, and the confirming terminal node can compare the paths of the received new PaS frame copies to confirm that there is no common node between them. If the common node does not exist, the checking terminal node updates its PrP table with the new path and proceeds to the next step. If the common node exists, it reports to the network administrator and, despite the common node, the new path. You can update your PrP table with. In this case, there may be no independent or separate dual virtual paths for the connection pair.

The terminal node then checks and sends an Open Block (OB) frame, a trusted special DVP unicast frame, to the BLO node. This is to unblock its port connecting with the common node in front of future PaS frames belonging to the same connection pair. As soon as the BLO node receives the OB frame, it unblocks and sends a special DVP frame called ACK OB to the terminal node acknowledging that it informs the terminal node that the deblocking has been performed.

Subsequently, the network traffic reduction method using the DVP algorithm according to an embodiment of the present invention transmits a data frame from a source terminal node to a destination terminal node via at least one path of DVP.

As shown in FIG. 7, in the step of transmitting the data frame, the source terminal node copies the data frame and transmits the data frame in a dual virtual path with the destination terminal node, respectively.

In this case, when the data frame reaches the terminal node, the terminal node that has reached the data frame is based on at least one of whether the data frame is a unicast frame and whether the terminal node at which the data frame reached is the destination terminal node. The data frame may be processed by at least one method of receiving, discarding, deleting, and forwarding.

For example, as shown in FIG. 7, the terminal node can duplicate the data frame and transmit multicast or broadcast using standard HSR rules if the data frame reached is not a unicast frame.

Also, if the terminal node itself is the destination node, it may discard the data frame if it has received it according to whether it has received the same frame before, and if not, receive the data frame.

Also, if the terminal node itself is not the destination node and the same data frame has previously passed through it on the same port, the terminal node may delete the data frame, otherwise it may choose a different port than the one that received the data frame. Data frames can be forwarded through

When the data frame reaches the quadbox node as shown in Figure 8, the quadbox node that the data frame reaches is based on the standard HSR based on whether the data frame is a unicast frame and the final path table of the quadbox node reached. By convention, you can decide whether to process the data frame or forward the data frame to the appropriate output port.

For example, if the data frame reached is a broadcast or multicast data frame, or if there is no entry in the FP table for the connection pair that the data frame transmits, the quadbox node applies standard HSR rules to perform replication and random forwarding. Can be done.

Also, if there is an entry in the FP table for the connection pair that the data frame transmits, the quadbox node can forward the data frame to the appropriate output port for the connection pair of the received frame selected in the FP table.

As discussed above, if the quadbox node cannot find a suitable output port for a particular received frame in the FP table, the quadbox node can duplicate the corresponding copy of the frame and randomly forward to the next nodes. This ensures that the destination node receives at least one copy of the transmitted frame, in the same manner as the standard HSR transmission process. Thus, the DVP algorithm can ensure that no received frames are discarded or deleted.

In the method for reducing network traffic using the DVP algorithm according to an embodiment of the present invention, when a data frame is transmitted before the step of establishing the DVP is completed, each node may process the data frame according to standard HSR rules. . Thus, it is possible to ensure that no data frames are lost during the establishment of DVP.

In a method for reducing network traffic using a DVP algorithm according to an embodiment of the present invention, a first terminal node periodically copies a PHC frame, and transmits a copy to a second terminal node through one virtual path. The terminal node may further comprise monitoring the virtual path by returning an ACK PHC frame to the first terminal node upon receiving a copy of the transmitted PHC frame.

Here, the PHC frame is a DVP special unicast frame, which is transmitted from each terminal node to all terminal nodes contained on the FP table. The transmission process may occur within the PHC Duration Time of the PHC (DTPHC). The DTPHC may generally be assumed to be about 256 msec or 300 msec, for example, to secure a margin.

As described above, the ACK PHC frame returned by the second terminal node may be attached to the ACK PHC frame by the identification tag of the quadbox node passing through the ACK PHC frame back to the source node of the PHC frame, that is, the first terminal node.

Then, when the first terminal node receives all copies of the ACK PHC frame, it is checked whether all node identification tags attached to the copy are attached in the same order according to the PrP table of the first terminal node, and not attached in the same order. If not, one virtual path can be reestablished.

If the first terminal node does not receive one or two copies of the ACK PHC frame in DTAPHC, the first terminal node deletes the previous information collected from one of the received copies of the ACK PHC frame and retransmitted the PHC frame. Afterwards, you can wait as long as DTAPHC once more. If no further copies are received from each direction of the ACK PHC frame thereafter, the first terminal node reports to the network administrator and considers the node to be a dead node, the Ne and PrP of the first terminal node. Can be deleted from the table.

In addition to checking the state of the virtual path, PHC frames are useful for keeping the size of the PrP and FP tables of quadbox nodes as small as possible. Because whenever a PHC frame in a virtual path passes through a quadbox node, the PrP and FP tables of each quadbox node maintain entries for the virtual paths through that quadbox node to ensure that the virtual path is still alive. Because. If the terminal or quadbox node does not receive a PHC frame from the virtual path within a certain time, for example 2.6 seconds, the entry is obsolete and the node deletes the entry associated with the virtual path from the PrP table and the quadbox node. In this case, an entry related to the corresponding virtual path may also be deleted from the FP table.

In the network traffic reduction method using the DVP algorithm according to an embodiment of the present invention, a first terminal node unicasts a RePas frame to a second terminal node, and each quadbox node duplicates the RePas frame to copy the next node. The method may further include reestablishing the virtual path by transmitting a PaS frame to the first terminal node when the second terminal node receives the RePas frame.

The reestablishment of such a virtual path is performed when one of the terminal nodes does not receive both of the PaS frame copies from the corresponding node of the connection pair as described above, and when there is a common node in the DVP that was supposed to be separated and independent from each other. During the monitoring and maintenance procedure of, and virtual paths, one or two of the DVPs may not be able to deliver a PHC frame copy to the corresponding node of the connection pair.

For example, if the first terminal node has not received the PaS frame from the second terminal node included in the Ne table during the DTSPn time, the first terminal node may retransmit the PaS frame to the second terminal node after the DTSPn time has elapsed. You can request At this time, the first terminal node may transmit a RePaS frame to the second terminal node, and all quadbox frames may copy the RePaS frame and forward the copies to the next node while the RePaS frame is being transmitted. This is necessary to ensure transmission since there is no dual path between the first and second terminal nodes. After receiving the RePaS frame, the second terminal node may retransmit the PaS frame to the first terminal node, and the PaS frame may be duplicated and transmitted as well. At this time, the ID tag of the quadbox node in the middle may be attached. Quadbox nodes on the reestablished path can update the PrP and FP tables upon receipt of a new PaS frame. The first terminal node returns a PaC frame, and the quadbox node on the path to the second terminal node can confirm the last update.

The duration required for reestablishment is represented by the Duration Time of Path Reestablishment (DTPR), which can be estimated in a manner similar to DTSP and DTFP. In general, DTRP may be estimated to be 384 msec under normal circumstances. However, since the frames may need to be retransmitted when the above-mentioned frames are lost during transmission, the double 768 msec is used as an estimated value for margin.

As described above, the network traffic reduction method using the dual virtual path algorithm according to the present embodiment can improve network performance by reducing unnecessary redundant unicast traffic in the network. In order to measure the performance improvement, network-traffic parameters were used as an indicator of performance. The network-traffic parameter refers to the total number of frame copies moving over time, starting with the transmission of a frame until all the frames have been received or deleted.

9 is a diagram illustrating an example of an HSR network according to an embodiment of the present invention. As shown in FIG. 9, an example of the HSR network may include first to fourth example nodes 1-4 and fifth to eighth example nodes 5-8. The first through fourth example nodes 1-4 are terminal nodes and the fifth through eighth example nodes 5-8 are quadbox nodes. The terminal nodes have two ports each, and the quadbox nodes have four ports each. The terminal node can transmit two copies of one frame through different ports to different virtual paths.

In the example of FIG. 9, the network comprises four rings, each of which is connected to two different rings, which may give sufficient complexity in the path selection for the frame passing through the network. The performance of the DVP algorithm was measured through a simulation using the network shown in FIG. 9.

The DVP algorithm only works with unicast traffic types. The behavior of the DVP algorithm for multicast / broadcast traffic is similar to that of the standard HSR protocol, where the standard HSR protocol is used for each quadbox until it arrives at its destination or passes through the same node twice in order to be deleted or removed from the network. It only depends on the replication and random forwarding of the frames received at the node.

The following cases were considered in relation to the analysis for network traffic in both the standard HSR protocol and the DVP algorithm.

10 and 11 illustrate frame transmission of an error-free case under a standard HSR protocol. FIG. 10 is a diagram illustrating frame transmission under a standard HSR protocol as a result of transmitting a unicast frame from a first example node 1 to a second example node 2 according to an embodiment of the present invention, and FIG. A frame transmission under the standard HSR protocol as a result of transmitting a unicast frame from the third example node 3 to the first example node 1 according to an embodiment of the present invention.

Table 1 shows a detailed sample of a connection pair in the case where each source node transmits a unicast frame to each different destination node in the example of the network shown in FIG. 9.

Table 1

#	Source node number	Destination node number
One	One	3
2	2	4
3	3	2
4	4	One

Link-failure cases under the standard HSR protocol include, for example, a failure during network operation on the link between the first example node 1 and the fifth example node 5.

12 and 13 are diagrams illustrating frame transmission of a node-failure case under a standard HSR protocol. In the example of FIGS. 12 and 13, the failed node is the fifth example node 5.

12 is a diagram illustrating frame transmission under a standard HSR protocol as a result of transmitting a unicast frame from a first example node 1 to a second example node 2 in a node-failure case according to an embodiment of the present invention. FIG. 13 is a diagram illustrating frame transmission under a standard HSR protocol as a result of transmitting a unicast frame from a third example node 3 to a first example node 1 in a node-failure case according to an embodiment of the present invention.

In this case, the failure of the fifth example node 5 causes the failure of all links connected to it, and this failure causes the link and the destination between the second example node 2 and the sixth example node 6, which are destination nodes. The node between the first example node 1 and the eighth example node 8 is deleted from one of two circular frames (one in each direction).

As previously used in connection with the analysis of network traffic under the DVP algorithm, when sending a unicast frame from the first example node 1 to the second example node 2, the third example node 3 receives the first In the case of transmitting a unicast frame to the example node 1 and in the case of Table 1, a fault-free case, a link-failure case, and a node-failure case were considered.

In each case described above, the result of comparing traffic of the standard HSR protocol and the DVP algorithm is as follows.

Table 2 shows a comparison of network traffic under standard HSR protocol and DVP algorithm in a faultless case.

TABLE 2

#	scenario	Standard HSR (Frame)	DVP (frame)	Reduction
One	First Example Node- Second Example Node	21	6	71.4%
2	Third Example Node- First Example Node	22	6	72.7%
3	Scenarios in Table 1	86	24	72.1%

In Table 2, the first scenario where the first example node 1 sends one frame to the second example node 2 shows 71.4% less network traffic under the DVP algorithm than in the standard HSR protocol. This means that unnecessary redundant traffic exists and circulates the network without gain, so flooding such traffic within the network may cause delays or network congestion.

Even in the second and third scenarios, the DVP algorithm outperforms the standard HSR protocol. The reduction rate is calculated by the following equation.

[Equation 1]

Decrease Rate = 1-(DVP Traffic / Standard HSR Traffic) * 100%

Table 3 shows a comparison of network traffic under standard HSR protocol and DVP algorithm in a link-failure case.

TABLE 3

#	scenario	Standard HSR (Frame)	DVP (frame)	Reduction
One	First Example Node- Second Example Node	19	4	78.9%
2	Third Example Node- First Example Node	21	5	76.2%
3	Scenarios in Table 1	76	20	73.7%

For the first scenario, the network performance under DVP is better than the standard HSR protocol as shown in Table 3 above, but the DVP algorithm provides only one path between the first example node (1) and the second example node (2). It was. The second path worked properly, while the first path (first example node-fifth example node-second example node) failed the link between the first example node (1) and the fifth example node (5). Because it was down. Nevertheless, the DVP algorithm always provides dual physically separate paths for each connection pair, so in the case of link failure, the worst effect in the DVP algorithm is not on both paths, but on any connection pair or few connection pairs. Only one path is lost for them.

That is, the failure case is a temporary state that is repaired for a very short time of up to 3150 msec when the DVP algorithm is restarted, so that the failure case can be recovered. In other scenarios, the DVP algorithm outperforms the standard HSR protocol.

Table 4 shows a comparison of network traffic under standard HSR protocol and DVP algorithm in a node-failure case.

Table 4

#	scenario	Standard HSR (Frame)	DVP (frame)	Reduction
One	First Example Node- Second Example Node	14	4	71.4%
2	Third Example Node- First Example Node	14	4	71.4%
3	Scenarios in Table 1	50	14	72.0%

According to Table 4, compared to the previous cases, network traffic under the standard HSR protocol is significantly reduced. This is because the network has lost four linked quadlink nodes and each of the links has two frame copies that pass during each transmission operation. Under the DVP algorithm, network traffic always changes within the range of two to six frames.

If the two paths of a connection pair are operating normally without failure, the maximum network traffic for each frame transmitted within this connection pair will be 6 frames each with 4 links, while the minimum network The traffic will be 2 frames if the second path goes down. And if only the primary path is fault-free and consists of two links, the maximum traffic will be 2 frames per transmission operation. In this case, however, the network traffic under the standard HSR protocol does not even reach the maximum network traffic value under the DVP algorithm, so the DVP algorithm prevails. Moreover, as mentioned above, in the DVP algorithm, the fault case is a temporary state and is recovered after a certain time. Thus, for all cases and scenarios, DVP algorithms always outperform standard HSR protocols.

In order to verify the analysis results derived above, a plurality of simulations were performed on the network example shown in FIG. 9 using the simulation tool OMNeT ++ V4.2.2, and the above cases were tested in the established simulation environment. This is consistent with one theoretical derivation result. Therefore, hereinafter, only the comparison result of discarded frames will be described.

Table 5 shows a comparison of discarded traffic between the standard HSR protocol and the DVP algorithm in a faultless case.

Table 5

#	scenario	Standard HSR (Frame)	DVP (frame)	Reduction
One	First Example Node- Second Example Node	9	One	88.9%
2	Third Example Node- First Example Node	9	One	88.9%
3	Scenarios in Table 1	36	4	88.9%

Table 6 shows a comparison of discarded traffic between standard HSR protocol and DVP algorithm in a link-fault case.

Table 6

Table 7 shows a comparison of discarded traffic between the standard HSR protocol and the DVP algorithm in a node-failure case.

TABLE 7

#	scenario	Standard HSR (Frame)	DVP (frame)	Reduction
One	First Example Node- Second Example Node	7	One	85.7%
2	Third Example Node- First Example Node	7	One	85.7%
3	Scenarios in Table 1	28	4	85.7%

In addition, similar to the scenario of Table 1, this time five experiments were performed under the new scenario, not once under each disorder-free and failure case. During the first experiment, 10 frames would be transmitted from each transmitting node, and a new experiment was performed until the number of frames transmitted at each node was increased by 10 to reach 50 frames. 14 to 16 are graphs showing simulation results according to this new scenario.

15 is a graph comparing network traffic and discarded traffic between the HSR standard and DVP algorithm of a link-fault case in accordance with an embodiment of the present invention.

16 is a graph comparing network traffic and discarded traffic between the HSR standard and DVP algorithm of a node-fault case in accordance with an embodiment of the present invention.

FIG. 14 shows that a 72.1% reduction in network traffic of the DVP algorithm is obtained and 88.9% reduction for discarded traffic in a faultless case compared to the standard HSR protocol. 15 and 16 show that both network traffic and discarded traffic are reduced in the DVP algorithm in failure cases. In all cases, the reduction rate is constant with respect to the number of transmitted frames respectively, for example, when each terminal node transmits 10 frames in FIG. 15, the reduction rate is 73.7% and transmits 20 or 30 frames or the like. The same value is also applicable to the case. Thus, the reduction rate is constant if the number of transmissions of frames in the DVP algorithm and the standard HSR protocol is similar.

The performance of the DVP algorithm is the standard HSR in all simulation results, considering that the simulations were performed on the worst case and scenarios where failures occurred and long-term failure conditions were obtained to obtain equivalent conditions for the DVP algorithm and the standard HSR protocol. Better than protocol

In general, the performance of the DVP algorithm is proportional to the network size, because frames will travel in several virtual paths instead of spreading across all network paths.

As described above, according to the present embodiment, the performance of the network can be improved by reducing unnecessary redundant unicast traffic in the network.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art to which the art belongs can make various modifications and other equivalent embodiments therefrom. Will understand. Therefore, the technical protection scope of the present invention will be defined by the claims below.

Claims

Declaring a terminal node by each terminal node broadcasting a declaration frame and generating a neighbor table where each first node includes information about terminal nodes in a network based on the declaration frame;

For each first and second terminal node pair, the first terminal node unicasts a path selection frame to the second terminal node with reference to its neighbor table, and each second node is sent to the path selection frame. Establishing a dual virtual path between the first and second terminal nodes by generating a prepass table that includes path information from the first terminal node to a second terminal node based on the step; And

Transmitting a data frame from a source terminal node to a destination terminal node over at least one of the dual virtual paths.
The method of claim 1,

In the step of declaring the terminal node,

If the source node of the received declaration frame is not itself and the received declaration frame has not passed through the first node, the first node reads the received declaration frame and reads the MAC address of the source node of the received declaration frame. And adding the sequence number of the received declaration frame to the neighbor table.
The method of claim 2,

And the first node deletes the received declaration frame when the source node of the received declaration frame is itself.
The method of claim 2,

At least one of the first node if the received declaration frame has already passed, and the MAC address of the source node of the received declaration frame and the sequence number of the received declaration frame are displayed in the neighbor table; The network traffic reduction method, characterized in that for processing the received declaration frame according to the standard HSR rules.
The method of claim 1,

In establishing the dual virtual path,

And the second terminal node is a terminal node having a MAC address included in a neighbor table of the first terminal node.
The method of claim 1,

In establishing the dual virtual path,

If the second node is a terminal node and is not a source node and a destination node of the received path selection frame, the second node forwards the received path selection frame to a port different from the port where the received path selection frame is received. Deleting the received path selection frame if the selection frame was previously forwarded to a different port than the received port.
The method of claim 1,

In establishing the dual virtual path,

If the second node is a terminal node and is a destination node of the received path selection frame, the second node receives another copy of the received path selection frame from a port different from the port receiving the received path selection frame, and receives the received path. And generating or updating a prepass table with information about the selection frame, and returning a path confirmation frame to a source node of the received path selection frame.
The method of claim 7, wherein

The received path selection frame information may include an input port number at which the received path selection frame is received, MAC addresses of source and destination nodes of the received path selection frame, and a quadbox node attached to the received path selection frame. And an identification tag of the network traffic reduction method.
The method of claim 1,

In establishing the dual virtual path,

When the second node is a quadbox node, a prepass table is generated with information about a path selection frame that reaches the second node most quickly among path selection frames transmitted from the first terminal node to the second terminal node. Or update, attach the identification tag of the second node to the reached path selection frame, and duplicate both the reached path selection frame and forward both the reached path selection frame and the duplicated path selection frame. , How to reduce network traffic.
The method of claim 9,

The information about the reached path selection frame includes the sequence number of the reached path selection frame, the MAC address of the source and destination nodes of the reached path selection frame, and the identification tag of the quadbox node attached to the reached path selection frame. The network traffic reduction method comprising the.
The method of claim 9,

If the second node is a quadbox node,

After a preset second step time elapses, information about the terminal node pair in which the path confirmation frame does not pass through the second node among the terminal node pairs included in the freepath table of the second node is provided. Deleting from the freepath table of the method.
The method of claim 9,

If the second node is a quadbox node,

And after the preset second step time elapses, the second node generates a final path table in which the MAC addresses of the source and destination nodes in the free pass table are inverted from each other.
The method of claim 1,

In establishing the dual virtual path,

Compares identification tags included in path selection frames transmitted between the first and second terminal nodes received by at least one of the first and second terminal nodes to determine whether a common node exists between the dual virtual paths. Determining whether the network traffic is reduced.
The method of claim 13,

The confirming terminal node requests that a blocking node block a port connected to the common node in connection with transmission between the first and second terminal nodes when the common node exists, and the first and second Request to reestablish a path between two terminal nodes, and request the blocking node to release the block after a path in which a common node does not exist between the first and second terminal nodes is reestablished. Network traffic reduction method.
The method of claim 1,

In the step of transmitting the data frame,

And said source terminal node copies said data frame and transmits each in said dual virtual path with said destination terminal node.
The method of claim 1,

In the step of transmitting the data frame,

When the data frame reaches the terminal node,

The terminal node that has reached the data frame receives and discards the data frame based on at least one of whether the data frame is a unicast frame and whether the terminal node at which the data frame arrives is the destination terminal node. And at least one of the method of deleting or forwarding.
The method of claim 1,

In the step of transmitting the data frame,

When the data frame reaches the quadbox node,

The quadbox node upon which the data frame arrives will process the data frame according to standard HSR rules based on whether the data frame is a unicast frame and the final path table of the quadbox node reached, or the data Determining whether to forward the frame to the appropriate output port.
The method of claim 1,

In the step of transmitting the data frame,

If the data frame is transmitted before the step of establishing the dual virtual path is completed, each node processes the data frame according to standard HSR rules.
The method of claim 1,

The first terminal node periodically copies the path health confirmation frame and transmits copies of the path health confirmation frame to the second terminal node through one virtual path, and the second terminal node sends a copy of the transmitted path health confirmation frame. And monitoring the virtual path by returning a path integrity confirmation acknowledgment frame to the first terminal node when received.
The method of claim 19,

In the monitoring of the virtual path, when the first terminal node receives all copies of the path health confirmation acknowledgment frame, all node identifier tags attached to the copies are added to the free pass table of the first terminal node. And confirming that they are attached in the same order, and reestablishing the one virtual path if they are not attached in the same order.
The method of claim 1,

The first terminal node unicasts a repath selection frame to the second terminal node, each quadbox node duplicates the repath selection frame and forwards copies to the next node, wherein the second terminal node Reestablishing the virtual path by transmitting the path selection frame to the first terminal node upon receiving a repath selection frame.