Network switch and network architecture supporting the integration and backup of heterogeneous networks

Abstract

To provide a primary network switch, a backup network switch, and a network architecture.SOLUTION: A network system includes a primary network switch 22 that is configured in a main network operating with a redundancy protocol A, is used for coupling a sub-network operating with a redundancy protocol B, and executes a backup method. The backup method includes: sending a first control packet through at least one first connection port; receiving an ACK packet of the first control packet; switching a state of a second connection port; sending a second control packet through the at least one first connection port according to the redundancy protocol A to update a medium access control address table of the main network; and sending a third control packet through the second connection port according to the redundancy protocol B to update a medium access control address table of the sub-network.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a network coupling and backup device and network architecture, and more particularly to a network switch and network architecture for coupling and backup of heterogeneous networks. [Background technology]

[0002] As industrial demands for production capacity and cost continue to grow, connecting production equipment to networks has become a trend. Network connectivity enables data collection and analysis across multiple devices, improving process speed, flexibility, and efficiency, reducing costs, and providing higher-quality products. However, in traditional industrial environments, multiple independent local area networks (LANs) often coexist, making integration and management difficult. In such cases, prior art has proposed network integration technologies that can connect multiple local area networks to each other and enable data and function sharing or integration between different local area networks. Such technologies can solve the problem of intercommunication between different local area networks and improve system efficiency and scalability.

[0003] Generally, industrial control network architectures may require multiple different subnetworks accessing a main network (backbone network). To ensure network stability and reliability, industrial control networks often implement redundancy protocols, such as Rapid Spanning Tree Protocol (RSTP) and Media Redundancy Protocol (MRP), while the main network often implements High-availability Seamless Redundancy (HSR) or a private redundancy protocol customized by a switch manufacturer. However, when combining networks, the main network and its connected subnetworks generally need to use the same redundancy protocol to operate, making it difficult to scale the network architecture when using multiple different redundancy protocols.

[0004] Although the prior art has proposed heterogeneous network connection technologies, there are many limitations on the connection methods and devices for network connection, such as the need for the main path and backup path of a subnetwork to connect to adjacent network nodes of the main network, the network nodes for connection need to simultaneously run two different redundancy protocols for the main network and the subnetwork, or the main network needs to forward control packets of the redundancy protocol required for the subnetwork, which makes it difficult to maintain the performance of the network nodes and the main network, and the problem becomes even more serious when a large number of subnetworks are connected. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Taiwan Patent No. I612783 [Patent Document 2] US Patent No. 9,191,273 [Non-patent literature]

[0006] [Non-Patent Document 1] User Manual, Redundancy Configuration Industrial ETHERNET Switch RS20, RSB20, 2010 / 07, P. 28-31, 68-71, Hirschmann Automation and Control GmbH, Neckartenzlingen, Germany. [Non-patent document 2] What options do you have for connecting an (R)STP segment to a ring structure and how can you reduce the ring reconfiguration time through the EPLC procedure?, 2018 / 04 / 25. Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an object of the present invention is to provide a method and apparatus for network coupling of heterogeneous networks, in which the main network and the sub-networks operate according to different redundancy protocols when performing network coupling, thereby realizing a redundancy mechanism and improving performance. [Means for solving the problem]

[0008] An embodiment of the present invention provides a main network switch configured in a main network operating under a first redundancy protocol and used to couple a sub-network operating under a second redundancy protocol, the main network switch including: at least one first connection port coupled to the main network; a second connection port coupled to the sub-network; a processing unit configured to execute program code; and a storage unit connected to the processing unit and storing program code for instructing the processing unit to execute a backup method for network coupling, the backup method including: transmitting a first control packet through the at least one first connection port; receiving an ACK packet for the first control packet when the first control packet has been sent; switching a state of the second connection port when the ACK packet for the first control packet has been received; transmitting a second control packet through the at least one first connection port according to the first redundancy protocol to update a media access control address table (MAC address table) of the main network; and transmitting a third control packet through the second connection port according to the second redundancy protocol to update the media access control address table of the sub-network.

[0009] An embodiment of the present invention further provides a backup network switch configured in a main network operating under a first redundancy protocol and used to couple a sub-network operating under a second redundancy protocol, the backup network switch including: at least one first connection port coupled to the main network; a second connection port coupled to the sub-network; a processing unit configured to execute program code; and a storage unit connected to the processing unit and storing program code for instructing the processing unit to execute a backup method for network coupling, the backup method including the steps of: switching a state of the second connection port; and transmitting a first control packet via the at least one first connection port according to the first redundancy protocol to update a media access control address table (MAC address table) of the main network; and transmitting a second control packet via the second connection port according to the second redundancy protocol to update the media access control address table of the sub-network.

[0010] An embodiment of the present invention is a network architecture for network coupling, comprising: a subnetwork operating according to a first redundancy protocol; a main network operating according to a second redundancy protocol; a main network switch provided in the main network, connected to the main network via at least one first connection port and connected to the subnetwork via a second connection port; and a backup network switch provided in the main network, connected to the main network via at least one third connection port and connected to the subnetwork via a fourth connection port, wherein the main network switch and the backup network switch perform a backup method for network coupling, the backup method comprising: the main network switch transmitting a first control packet via the at least one first connection port; upon receiving the first control packet, the backup network switch transmitting an ACK packet for the first control packet to switch a link; and transmitting a second control packet via the at least one third connection port according to the second redundancy protocol to update a media access control address table (MAC address table) of the main network. and sending a third control packet via the fourth connection port according to the first redundancy protocol to update a media access control address table of the sub-network; and upon receiving the ACK packet for the first control packet, the main network switch switches links and sends a fourth control packet via the at least one first connection port according to the second redundancy protocol to update a media access control address table of the main network, and sends a fifth control packet via the second connection port according to the first redundancy protocol to update a media access control address table of the sub-network. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a network system. [Figure 2] 1 is a partial schematic diagram of a network system according to an embodiment of the present invention; [Figure 3] FIG. 2 is a schematic diagram of a polling process of a network connection backup method according to an embodiment of the present invention; [Figure 4] 3 is a schematic diagram of an aspect of a polling process performed by a network system according to an embodiment of the present invention. [Figure 5] FIG. 2 is a schematic diagram of a link validation process of a network connection backup method according to an embodiment of the present invention; [Figure 6] 3 is a schematic diagram of aspects of a link activation process performed by a standby network switch in accordance with an embodiment of the present invention. [Figure 7] FIG. 4 is a schematic diagram of aspects of a link activation process performed by a main network switch in accordance with an embodiment of the present invention. [Figure 8] FIG. 4 is a schematic diagram of a polling process performed by a standby network switch according to an embodiment of the present invention. [Figure 9] FIG. 4 is a schematic diagram of a polling process performed by a main network switch according to an embodiment of the present invention. [Figure 10] 2 is a schematic diagram of a link switching process of a network connection backup method according to an embodiment of the present invention; [Figure 11] 2 is a schematic diagram of an aspect of a link switching process performed by a network system according to an embodiment of the present invention; [Figure 12] 2 is a schematic diagram of an aspect of a link switching process performed by a network system according to an embodiment of the present invention; [Figure 13A] 13A and 13B are schematic diagrams of other aspects of a link switching process performed by a network system according to an embodiment of the present invention. [Figure 13B] 13A and 13B are schematic diagrams of other aspects of a link switching process performed by a network system according to an embodiment of the present invention. [Figure 14]FIG. 4 is a schematic diagram of another aspect of a link switching process performed by a network system according to an embodiment of the present invention. [Figure 15] FIG. 2 is a schematic diagram of a link switching process performed by a main network switch according to an embodiment of the present invention. [Figure 16] FIG. 2 is a schematic diagram of a link switching process performed by a standby network switch according to an embodiment of the present invention. [Figure 17] 1 is a schematic diagram of a chain network connection according to an embodiment of the present invention; [Figure 18] 1 is a schematic diagram of implementing a network connection backup method when connecting chained networks according to an embodiment of the present invention; [Figure 19] 1 is a schematic diagram of a network device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0012] Throughout this specification and the following claims, specific terms are used to refer to specific elements. Those skilled in the art will understand that hardware manufacturers may refer to the same component by different nouns. Throughout this specification and the following claims, elements are distinguished by their function, not by their name. The term "comprising" used throughout this specification and the following claims is an open-ended term and should be interpreted as "including, but not limited to." Furthermore, the term "connected" includes both direct and indirect electrical connection means. Thus, in this specification, a first device connected to a second device means that the first device may be directly electrically connected to the second device or may be indirectly electrically connected to the second device via other devices or connections.

[0013] FIG. 1 is a schematic diagram of a network system 1. As shown in FIG. 1, in the network system 1, one main network 10 connects multiple subnetworks 12_1 to 12_3. Here, the main network 10 operates according to redundancy protocol A, and the subnetworks 12_1 to 12_3 operate according to redundancy protocols B to D, respectively. Specifically, the main network 10 is connected to the subnetworks 12_1 to 12_3 via multiple main links via multiple main network switches 14_1 to 14_3. At the same time, the main network 10 is connected to the subnetworks 12_1 to 12_3 via multiple backup links via multiple backup network switches 16_1 to 16_3. Here, the multiple backup network switches 16_1 to 16_3 and their backup links are in a standby state as backups for the multiple main network switches 14_1 to 14_3 and their main links. As can be seen from FIG. 1, the network system 1 may be connected to multiple networks using different redundancy protocols. In the prior art, switches connecting subnetworks must simultaneously execute two different redundancy protocols. For example, network switches 14_1 and 16_1 must simultaneously execute redundancy protocols A and B, network switches 14_2 and 16_2 must simultaneously execute redundancy protocols A and C, and network switches 14_3 and 16_3 must simultaneously execute redundancy protocols A and D. This operating method increases the efficient load on the network switches. On the other hand, in the prior art, the entire main network 10 is treated as a single path, and control packets related to the redundancy protocols of the subnetworks 12_1 to 12_3 can be transferred in the main network 10. In this case, as the number of connected subnetworks increases, the amount of control packets on the main network 10 also increases, affecting performance. Furthermore, in the prior art, it may be impossible to simultaneously connect networks compatible with three or more redundancy protocols.

[0014] Therefore, the present invention proposes a network interconnection architecture and a network switch backup method therein that overcomes the drawbacks of the prior art. Here, the primary network switch, the backup network switch, and the links connecting them to their subnetworks can be regarded as an interconnection network, which serves as a communication bridge between the primary network and the subnetworks. When the network switch performs network backup such as link switching, it can notify the primary network and the subnetworks of new route information according to the redundancy protocol for the primary network and the subnetworks. This allows the primary network and the subnetworks to connect and communicate with each other even when they are operating according to different redundancy protocols, resulting in stable performance without mutual interference.

[0015] 2 is a partial schematic diagram of the network system 1 of FIG. 1. Specifically, FIG. 2 shows a connection topology among a main network 10, a subnetwork 20, a main network switch 22, and a backup network switch 24 according to an embodiment of the present invention. Here, the subnetwork 20 represents one of the subnetworks 12_1 to 12_3 in the network system 1 of FIG. 1, the main network switch 22 represents a main network switch corresponding to the subnetwork 20 in the main network switches 14_1 to 14_3, and the backup network switch 24 represents a backup network switch corresponding to the subnetwork 20 in the backup network switches 16_1 to 16_3. As shown in FIG. 2, the main network switch 22 is configured in the main network 10, and is connected to the main network 10 via connection ports 222 and 224 and links L3 and L4, and is connected to the subnetwork 20 via connection port 220 and link L1, thereby transferring data. Meanwhile, the backup network switch 24 is configured in the main network 10, connected to the main network 10 via connection ports 242 and 244 via links L5 and L6, and connected to the subnetwork 20 via connection port 240 via link L2, and stands by as a backup for the main network switch 22. Note that although the main network 10 is shown as a ring network in FIG. 2, this is not a limitation, and the main network 10 may have various types of network topologies and be suitable for various redundancy protocols. Thus, although the main network switch 22 and the backup network switch 24 are shown connected to the main network 10 via two connection ports, this is not a limitation, and the main network 10 may be connected to the main network 10 via different numbers of connection ports and links according to different network topologies. Also, although the main network switch 22 and the backup network switch 24 are shown adjacent to each other in FIG. 2, this is not a limitation.The main network switch 22 and the backup network switch 24 may be adjacent (links L4 and L5 are the same link) or may be connected via other network devices (not shown in FIG. 2) on the main network 10 (links L4 and L5 are different links).

[0016] In the embodiment of FIG. 2, the network system 1 can be considered to be composed of three networks N1 to N3 for operating a backup mechanism. Network N1 is a main network 10, includes a main network switch 22 and a backup network switch 24, and operates according to redundancy protocol A. If any device or link fails or becomes disabled, backup may be performed according to the operation of redundancy protocol A. Network N2 is a sub-network 20, includes network switches 26 and 28, and operates according to redundancy protocol B. If any device or link fails or becomes disabled, backup may be performed according to the operation of redundancy protocol B. Networks N1 and N2 operate according to different redundancy protocols and do not affect each other. Meanwhile, network N3 includes main network switch 22, backup network switch 24, network switches 26 and 28, and links L1 and L2, i.e., the above-mentioned coupled network. When any device or link fails or becomes disabled, links L1 and L2 are switched, without affecting the operation of different redundancy protocols in main network 10 and subnetwork 20. Specifically, when link switching is performed in network N3, main network switch 22 and backup network switch 24 may send a topology update notification to main network 10 according to redundancy protocol A via connection ports 222 and 224 and connection ports 242 and 244, respectively. At the same time, main network switch 22 and backup network switch 24 may send a topology update notification to subnetwork 20 according to redundancy protocol B via connection port 220 and connection port 240, respectively. In this way, network coupling can be prevented from being restricted by different redundancy protocols.

[0017] One embodiment of the backup method for network coupling in the network system 1 may be summarized as a polling process 30, as shown in Figure 3. The polling process 30 includes the following steps.

[0018] Step 300: The process begins.

[0019] Step 302: The standby network switch 24 periodically transmits a polling packet P1.

[0020] Step 304: The main network switch 22 determines whether the time during which the first polling packet P1 has not been received has reached a predetermined time. If YES, execute step 306; if not, execute step 308.

[0021] Step 306: The primary network switch 22 executes a link activation process.

[0022] Step 308: When the polling packet P1 is received, the main network switch 22 returns an ACK packet P1_ACK.

[0023] Step 310: The backup network switch 24 determines whether the number of times that the ACK packet P1_ACK has not been received has reached a predetermined number. If YES, execute step 312; if not, execute step 314.

[0024] Step 312: The standby network switch 24 performs a link activation process.

[0025] Step 314: End the process.

[0026] FIG. 4 is a schematic diagram of an aspect of a polling process 30 executed by the network system 1 according to an embodiment of the present invention. As shown in FIG. 4, the polling process 30 causes the backup network switch 24 to periodically transmit a polling packet P1 in the main network 10 via the connection ports 242 and 244 (step 302) and determine the status of the main network switch 22 based on whether the main network switch 22 returns a packet P1_ACK (step 310). When the main network switch 22 receives the first control packet P1, the backup network switch 22 transmits an ACK packet P1_ACK in the main network 10 via the connection ports 222 and 224 (step 308). If the backup network switch 24 periodically transmits the polling packet P1 and does not receive the ACK packet P1_ACK a predetermined number of times, the backup network switch 24 may determine that the main network switch 22 has become disabled (e.g., due to a power outage or a fault). Therefore, the backup network switch 24 needs to perform a link activation process to activate the link L2 for communication with the subnetwork 20 (step 312). Another situation in which the ACK packet P1_ACK is not received may be caused by all links (L3, L4) between the main network switch 22 and the main network 10 being disabled at the same time, and the backup network switch 24 similarly needs to perform a link enabling process to enable link L2 to communicate with the sub-network 20 (step 312). Also, if all links (L5, L6) of the backup network switch 24 connected to the main network 10 are disabled at the same time, the backup network switch 24 similarly needs to perform a link enabling process to enable link L2 to communicate with the main network 10 and the sub-network 20 (step 312). Conversely, if the backup network switch 24 continues to receive the ACK packet P1_ACK from the main network switch 22, it can be determined that the main network switch 22 is operating normally, and the backup network switch 24 may remain in a standby state.In addition, immediately after the standby network switch 24 is started up, if the ACK packet P1_ACK has not yet been received, the standby network switch 24 does not perform the link activation process, thereby avoiding unnecessary link switching and ensuring system stability.

[0027] On the other hand, if the time period during which the main network switch 22 has not received the polling packet P1 periodically transmitted from the backup network switch 24 reaches a predetermined time (step 304), the main network switch 22 determines that the backup network switch 24 has been disabled and executes a link enablement process to enable the link L1 for communication with the subnetwork 20 (step 306). Similarly, another situation may occur in which the polling packet P1 has not been received because all links (L5, L6) between the backup network switch 24 and the main network 10 have been disabled at the same time, and the main network switch 22 similarly needs to execute the link enablement process to enable the link L1 for communication with the subnetwork 20 (step 306). Also, if all links (L3, L4) of the main network switch 22 connected to the main network 10 have been disabled at the same time, the main network switch 22 similarly needs to execute the link enablement process to enable the link L1 for communication with the main network 10 and the subnetwork 20 (step 306). Note that the main network switch 22 performs the link activation process only when the backup network switch 24 provides backup for the main network switch 22 via link L2. In other words, when the main network switch 22 and link L1 are operating normally and communication with the subnetwork 20 is performed via link L1, there is no need to perform the link activation process for link L1.

[0028] The link activation process performed by the primary network switch 22 and the backup network switch 24 may be summarized as a link activation process 50, as shown in Figure 5. The link activation process 50 includes the following steps.

[0029] Step 500: The process begins.

[0030] Step 502: Switch the connection port connected to the subnetwork 20 to a forwarding state.

[0031] Step 504: According to the redundancy protocol A, a topology update packet TC1 is transmitted from the connection port connected to the main network 10.

[0032] Step 506: According to redundancy protocol B, a topology update packet TC2 is transmitted from the connection port connected to the subnetwork 20.

[0033] Step 508: End the process.

[0034] FIG. 6 is a schematic diagram of a link activation process 50 executed by the standby network switch 24 in the network system 1 according to an embodiment of the present invention. FIG. 6 illustrates the link activation process performed by the standby network switch 24 in step 312 when the standby network switch 24 determines in step 310 that the primary network switch 22 has been disabled. As shown in FIG. 6 , according to the link activation process 50, in step 502, the standby network switch 24 first switches the state of the connection port 240 to a forwarding state (indicated by F). Next, the standby network switch 24 must notify the primary network 10 and the subnetwork 20, respectively, that the networks require a topology update. In step 504, the standby network switch 24 transmits a topology update packet TC1 in the primary network 10 via the connection ports 242 and 244 according to redundancy protocol A, and the network devices in the primary network 10 may update their media access control address tables (MAC address tables) based on the topology update packet TC1 (i.e., flush MAC). Meanwhile, in step 506, the backup network switch 24 may transmit a topology update packet TC2 to the subnetwork 20 via the connection port 240 in accordance with redundancy protocol B, and the network devices in the subnetwork 20 may update their media access control address tables based on the topology update packet TC2. This allows the networks of the primary network 10 and the subnetwork 20 to continue operating in accordance with redundancy protocols A and B, respectively. Note that although Figure 6 shows a case where the primary network switch 22 is disabled, this may also be applied to a case where links L3 and L4 are disabled simultaneously.

[0035] FIG. 7 is a schematic diagram of a link activation process performed by the main network switch 22 in the network system 1 according to an embodiment of the present invention. FIG. 7 illustrates the link activation process performed by the main network switch 22 in step 306 when the main network switch 22 determines in step 304 that the backup network switch 24 has been disabled. As shown in FIG. 7 , according to the link activation process 50, in step 502, the main network switch 22 first switches the state of the connection port 220 to a forwarding state (indicated by F). Next, the main network switch 22 must notify the main network 10 and the subnetwork 20, respectively, that a network topology update is required. In step 504, the main network switch 22 transmits a topology update packet TC1 in the main network 10 via the connection ports 222 and 224 according to the redundancy protocol A, and the network devices in the main network 10 may update their media access control address tables based on the topology update packet TC1. Meanwhile, in step 506, the main network switch 22 may transmit a topology update packet TC2 to the subnetwork 20 via the connection port 220 in accordance with the redundancy protocol B, and the network devices in the subnetwork 20 may update their media access control address tables based on the topology update packet TC2. This allows the networks of the main network 10 and the subnetwork 20 to continue operating in accordance with the redundancy protocols A and B, respectively. Note that although Figure 7 shows a case where the standby network switch 24 is disabled, this may also be applied to a case where the links L5 and L6 are disabled at the same time.

[0036] The above-described method for the standby network switch 24 to perform the polling process 30 may be summarized as a process 80, as shown in Figure 8. The process 80 includes the following steps.

[0037] Step 800: The process begins.

[0038] Step 802: A polling packet P1 is periodically transmitted.

[0039] Step 804: Wait for the ACK packet P1_ACK of the polling packet P1.

[0040] Step 806: Determine whether the ACK packet P1_ACK is received. If YES, execute step 804; if not, execute step 808.

[0041] Step 808: Determine whether the number of times that the ACK packet P1_ACK has not been received reaches a predetermined number. If YES, execute step 810; if not, execute step 804.

[0042] Step 810: Execute the link validation process.

[0043] Step 812: End the process.

[0044] According to process 80, the backup network switch 24 periodically transmits a polling packet P1 in the primary network 10 via the connection ports 242 and 244 (step 802) and waits for an ACK packet P1_ACK from the primary network switch 22 (step 804). This allows the backup network switch 24 to continuously monitor the status of the primary network switch 22. If the backup network switch 24 receives the ACK packet P1_ACK as scheduled, it determines that the primary network switch 22 is operating normally and continues to wait for the next ACK packet P1_ACK. If the backup network switch 24 does not receive the ACK packet P1_ACK from the primary network switch 22 for a predetermined number of consecutive times, it may perform further determinations (step 806). If the backup network switch 24 does not receive the ACK packet P1_ACK from the primary network switch 22 for a predetermined number of consecutive times, it may determine that the primary network switch 22 has been disabled and may therefore perform a link activation process to back up the primary network switch 22 (step 810). This allows the backup network switch 24 to switch the state of the connection port 240 to a forwarding state and notify the primary network 10 and the subnetwork 20 of network topology updates according to redundancy protocols A and B, respectively.

[0045] The above-described manner in which the main network switch 22 performs the polling process 30 may be summarized as a process 90, as shown in Figure 9. The process 90 includes the following steps:

[0046] Step 900: The process begins.

[0047] Step 902: Wait for the polling packet P1.

[0048] Step 904: Determine whether the polling packet P1 has been received. If YES, execute step 906; if not, execute step 908.

[0049] Step 906: An ACK packet P1_ACK for the polling packet P1 is transmitted.

[0050] Step 908: Determine whether the time during which the polling packet P1 has not been received has reached a predetermined time. If YES, execute step 910; if not, execute step 902.

[0051] Step 910: Execute the link validation process.

[0052] Step 912: End the process.

[0053] According to process 90, the main network switch 22 waits for a polling packet P1 from the backup network switch 24 and sends an ACK packet P1_ACK for the polling packet P1 via the connection ports 222 and 224. This allows the main network switch 22 to feedback its own status while simultaneously monitoring the status of the backup network switch 24. First, the main network switch 22 continues to wait for a polling packet P1 from the backup network switch 24 (step 902). If the main network switch receives the polling packet P1, it may determine that the backup network switch 24 is operating normally and continue to wait for the next polling packet P1. If the main network switch does not receive the polling packet P1, further determination is made (step 904). After receiving the polling packet P1, the main network switch 22 sends an ACK packet P1_ACK to the backup network switch 24 in response (step 906). If the time during which the main network switch 22 has not received the polling packet P1 reaches a predetermined time (step 908), it may determine that the backup network switch 24 has been disabled and perform a link activation process to connect the subnetwork 20 (step 910). As a result, the main network switch 22 switches the state of the connection port 220 to a forwarding state, and notifies the main network 10 and the sub-network 20 of the network topology update in accordance with redundancy protocols A and B, respectively.

[0054] This allows the polling process 30 to allow the primary network switch 22 and the backup network switch 24 in the network system 1 to monitor each other's status and enable links between the subnetworks 20 for communication as needed.

[0055] Furthermore, in addition to monitoring the status of the main network switch 22 and the backup network switch 24, the network system 1 also needs to simultaneously monitor the status of the links L1 and L2, and if either of the links L1 and L2 becomes invalid, switch the link in a timely manner to maintain communication between the main network 10 and the subnetwork 20. In an embodiment of the present invention, one aspect of the backup method for network coupling in the network system 1 may be summarized as a link switching process 100, as shown in FIG. 10. The link switching process 100 includes the following steps:

[0056] Step 1000: The process begins.

[0057] Step 1002: The main network switch 22 detects the connection status of the link L1.

[0058] Step 1004: The main network switch 22 determines whether the connection state of the link L1 has changed. If YES, execute step 1006; if not, execute step 1002.

[0059] Step 1006: The main network switch 22 determines whether the connection state of the link L1 is in a connected (link-up) state or a disconnected (link-down) state. If it is in a connected state, it executes step 1008, and if it is in a disconnected state, it executes step 1012.

[0060] Step 1008: The main network switch 22 sends a link confirmation packet LT1 via the link L1.

[0061] Step 1010: If the link confirmation packet LT1 has been received or the timer has expired, execute step 1012.

[0062] Step 1012: The main network switch 22 sends a link switching packet LC1.

[0063] Step 1014: When the link switching packet LC1 is received, the backup network switch 24 returns an ACK packet LC1_ACK.

[0064] Step 1016: The primary network switch 22 and the backup network switch 24 perform link switching.

[0065] Step 1018: End the process.

[0066] According to the process 100, the main network switch 22 must constantly monitor the connection status of the link L1 connected to the subnetwork 20, and may determine whether the link L1 is in a connected or disconnected (disabled) state based on whether it receives an electrical signal from the link L1 (step 1002). If the status of the link L1 changes, the main network switch 22 must further determine a subsequent action (step 1004). When the status of the link L1 transitions from a connected state to a disconnected state, the backup network switch 24 performs backup and switches the connection link between the main network 10 and the subnetwork 20 to the link L2 (steps 1012 to 1016). When the status of the link L1 transitions from a disconnected state to a connected state, the main network switch 22 further sends a link confirmation packet LT1 to the subnetwork 20 to confirm the status of the link L1, and switches the connection link between the main network 10 and the subnetwork 20 to the link L1 (steps 1008 to 1016). If link switching is required, the main network switch 22 may transmit a link switching packet LC1 in the main network 10 via the connection ports 222 and 224 to notify the backup network switch 24 of the switching of links L1 and L2 (step 1012). Upon receiving the link switching packet LC1, the backup network switch 24 transmits an ACK packet LC1_ACK for the link switching packet LC1 in the main network 10 via the connection ports 242 and 244 (step 1014) to perform link switching. In step 1016, the main network switch 22 and the backup network switch 24 must each perform link switching. In step 1016, similar to the link activation process 50 described above, the main network switch 22 and the backup network switch 24 change the states of the connection ports 220 and 240 corresponding to the links L1 and L2 connected to the subnetwork 20, and transmit topology update packets TC1 and TC2 to the main network 10 and the subnetwork 20, respectively.

[0067] 11 and 12 are schematic diagrams of aspects of a link switching process 100 executed by the network system 1 according to an embodiment of the present invention. Here, FIG. 11 specifically illustrates a case where it is determined in step 1006 that link L1 has transitioned from a connected state to a disconnected state. In step 1012, the main network switch 22 may transmit a link switching packet LC1 to the main network 10 via the connection ports 222 and 224. Next, in step 1014, upon receiving the link switching packet LC1, the backup network switch 24 returns an ACK packet LC1_ACK to the main network 10 via the connection ports 242 and 244, and performs link switching in accordance with the instruction of the link switching packet LC1.

[0068] 12, upon receiving the link switching packet LC1, the backup network switch 24 enables the link L2 for communication with the subnetwork 20 according to the instruction of the link switching packet LC1. Similar to the link enabling process 50, the backup network switch 24 needs to switch the connection port 240 connected to the subnetwork 20 to a forwarding state (denoted by F). Next, the backup network switch 24 needs to notify the primary network 10 and the subnetwork 20, respectively, that the networks require a topology update. The backup network switch 24 may send a topology update packet TC1 in the primary network 10 via the connection ports 242 and 244 according to a redundancy protocol A, and the network devices in the primary network 10 may update their media access control address tables based on the topology update packet TC1. Meanwhile, the backup network switch 24 may send a topology update packet TC2 to the subnetwork 20 via the connection port 240 according to a redundancy protocol B, and the network devices in the subnetwork 20 may update their media access control address tables based on the topology update packet TC2.

[0069] Meanwhile, when the main network switch 22 receives the ACK packet LC1_ACK from the backup network switch 24, the main network switch 22 switches the connection port 220 connected to the subnetwork 20 to a blocked state (indicated by B), and also needs to notify the main network 10 and the subnetwork 20 that a network topology update is required. Because the link L1 has been disabled, in this case, the main network switch 22 only needs to send the topology update packet TC1 in the main network 10 via the connection ports 222, 224 according to the redundancy protocol A, so that the network devices in the main network 10 can update their media access control address tables based on the topology update packet TC1.

[0070] 13A, 13B, and 14 are schematic diagrams of other aspects of the link switching process 100 executed by the network system 1 according to an embodiment of the present invention. Here, FIGS. 13A and 13B specifically show a case where it is determined in step 1006 that link L1 has transitioned from a disconnected state to a connected state. In this case, communication between the primary network 10 and the subnetwork 20 is switched from link L2 to link L1 and performed by the primary network switch 22, and the backup network switch 24 is again on standby.

[0071] 13A, the main network switch 22 may further transmit a link confirmation packet LT1 to the subnetwork 20 to confirm the status of the network switch 26 connected to link L1 on the subnetwork 20. In step 1008, the main network switch 22 may first transmit the link confirmation packet LT1 via link L1 via connection port 220. The link confirmation packet LT1 transmitted by the main network switch 22 on the main network 10 may be transmitted sequentially via link L1, subnetwork 20, and link L2, return to the main network 10, and finally be received by the main network switch 22 via connection port 222 or 224. Next, in step 1010, the main network switch 22 waits for the link confirmation packet LT1 to be transferred via the subnetwork 20 and returned to the main network 10, and then can confirm that link L1 and the network switch 26 connected to link L1 on the subnetwork 20 are ready, and may immediately perform link switching. On the other hand, if the main network switch 22 has not received the link confirmation packet LT1 transmitted by itself, it may wait for a timer to expire before performing link switching. If the link confirmation packet LT1 has been received or the timer has expired, the main network switch 22 may, in step 1012, send a link switching packet LC1 in the main network 10 via the connection ports 222 and 224 to notify the backup network switch 24 of the switching of the links L1 and L2. Next, in step 1014, if the link switching packet LC1 has been received, the backup network switch 24 returns an ACK packet LC1_ACK in the main network 10 via the connection ports 242 and 244, and performs link switching in accordance with the instructions of the link switching packet LC1.

[0072] As shown in FIG. 13B , in one aspect, when the network switch 26 connected to the link L1 receives the link confirmation packet LT1 transmitted by the main network switch 22, the network switch 26 may transmit an ACK packet LT1_ACK for the link confirmation packet LT1 to the main network switch 22 via the link L1. In step 1010, the main network switch 22 waits for an ACK packet LT1_ACK returned from the network switch 26 or for a timer to expire. If the network switch 26 can identify the link confirmation packet LT1, the network switch 26 returns an ACK packet LT1_ACK. The main network switch 22 may confirm, via the ACK packet LT1_ACK, that the link L1 and the network switch 26 are ready and immediately perform a link switch. If the network switch 26 cannot identify the link confirmation packet LT1, the main network switch 22 does not receive the ACK packet LT1_ACK from the network switch 26. In this case, the main network switch 22 waits for the timer to expire before performing a link switch.

[0073] 14, upon receiving link switching packet LC1, backup network switch 24 shuts down link L2 in accordance with the instruction of link switching packet LC1 and stops communication with subnetwork 20. Similar to link activation process 50, backup network switch 24 needs to switch connection port 240 connected to subnetwork 20 to a disconnected state. Next, backup network switch 24 needs to notify primary network 10 and subnetwork 20, respectively, that the networks require a topology update. Backup network switch 24 sends topology update packet TC1 to primary network 10 via connection ports 242 and 244 in accordance with redundancy protocol A so that network devices in primary network 10 can update their media access control address tables based on topology update packet TC1. Meanwhile, backup network switch 24 sends topology update packet TC2 to subnetwork 20 via connection port 240 in accordance with redundancy protocol B so that network devices in subnetwork 20 can update their media access control address tables based on topology update packet TC2.

[0074] On the other hand, when the main network switch 22 receives the ACK packet LC1_ACK from the backup network switch 24, the main network switch 22 switches the connection port 220 connected to the subnetwork 20 to a forwarding state, and similarly needs to notify the main network 10 and the subnetwork 20 that a topology update is required. In this case, the main network switch 22 needs to send a topology update packet TC1 in the main network 10 via the connection ports 222 and 224 according to the redundancy protocol A so that the network devices in the main network 10 can update their media access control address tables based on the topology update packet TC1. On the other hand, the main network switch 22 sends a topology update packet TC2 to the subnetwork 20 via the connection port 220 according to the redundancy protocol B so that the network devices in the subnetwork 20 can update their media access control address tables based on the topology update packet TC2.

[0075] Thus, the network system 1 monitors the states of the links L1 and L2, and switches the links appropriately according to the state of the link L1 so as to maintain communication between the primary network 10 and the subnetwork 20. In an embodiment of the present invention, the primary network switch 22 can further confirm the connection state of the link L1 via a link confirmation packet LT1 or an ACK packet LT1_ACK of the link confirmation packet, and can notify the backup network switch 24 of link switching via a link switching packet LC1. In addition, the primary network switch 22 and the backup network switch 24 can notify the primary network 10 and the subnetwork 20, respectively, to update their media access control address tables according to different redundancy protocols via topology update packets TC1 and TC2.

[0076] The above-described manner in which the main network switch 22 performs the link switching process 100 may be summarized as process 150. As shown in Figure 15, process 150 includes the following steps:

[0077] Step 1500: The process begins.

[0078] Step 1502: The connection state of the link L1 is detected.

[0079] Step 1504: Determine whether the connection state of link L1 has changed. If YES, execute step 1506; if not, execute step 1502.

[0080] Step 1506: Determine whether the connection state of the link L1 is a connected state or a disconnected state. If it is a connected state, execute step 1508; if it is a disconnected state, execute step 1518.

[0081] Step 1508: Send a link confirmation packet LT1 via link L1.

[0082] Step 1510: If the link confirmation packet LT1 has been received or the timer has expired, execute step 1512.

[0083] Step 1512: Send a link switching packet LC1.

[0084] Step 1514: If the ACK packet LC1_ACK for the link switching packet LC1 is received or the timer expires, execute step 1516.

[0085] Step 1516: The connection port 220 connected to the subnetwork 20 is switched to the forwarding state.

[0086] Step 1518: Send the link switching packet LC1.

[0087] Step 1520: If the ACK packet LC1_ACK for the link switching packet LC1 is received or the timer expires, execute step 1522.

[0088] Step 1522: The connection port 220 connected to the sub-network 20 is switched to the disconnected state.

[0089] Step 1524: Send the topology update packet TC1 via the connection ports 222 and 224 according to redundancy protocol A, and send the topology update packet TC2 via the connection port 220 according to redundancy protocol B.

[0090] Step 1526: End the process.

[0091] The above-described manner in which the standby network switch 24 performs the link switching process 100 may be summarized as a process 160, as shown in Figure 16. The process 160 includes the following steps.

[0092] Step 1600: The process begins.

[0093] Step 1602: Wait for a link switching packet LC1.

[0094] Step 1604: Determine whether or not the link switching packet LC1 is received. If YES, execute step 1606; if not, execute step 1602.

[0095] Step 1606: An ACK packet LC1_ACK for the link switching packet LC1 is transmitted.

[0096] Step 1608: Based on the link switching packet LC1, determine whether to enable or disconnect the link L2. If it is enabled, execute step 1610; if it is disconnected, execute step 1612.

[0097] Step 1610: The connection port 240 connected to the subnetwork 20 is switched to the forwarding state.

[0098] Step 1612: The connection port 240 connected to the sub-network 20 is switched to the disconnected state.

[0099] Step 1614: Send the topology update packet TC1 via the connection ports 242 and 244 according to the redundancy protocol A, and send the topology update packet TC2 via the connection port 240 according to the redundancy protocol B.

[0100] Step 1616: End the process.

[0101] In the embodiment of the present invention, messages are exchanged between the main network switch 22 and the backup network switch 24 via a polling packet P1, an ACK packet P1_ACK for the polling packet P1, a link switching packet LC1, and an ACK packet LC1_ACK for the link switching packet LC1. These messages are transmitted via the main network 10 and do not flow into the subnetwork 20. However, if the subnetwork 20 is a chain network, the subnetwork 20 does not have a sufficient redundancy mechanism to deal with link downs within the network. Therefore, a link down in the chain network may cause a partial interruption of network communication. In this case, the embodiment of the present invention transmits polling packets, ACK packets for the polling packets, link switching packets, and ACK packets for the link switching packets via the chain network to exchange messages between the main network switch 22 and the backup network switch 24. This also monitors the network status of the chain network. It should be noted that the method of transmitting polling packets, ACK packets for polling packets, link switching packets, and ACK packets for link switching packets through a chained network to pass messages between the main network switch 22 and the backup network switch 24 can be applied to networks with a variety of different network topologies and is not limited to chained networks.

[0102] FIG. 17 is a schematic diagram illustrating an embodiment of the present invention in which the subnetwork 20 is a chain network. In FIG. 17, network switches 26 and 28 are connected to the head and tail of the chain network, respectively, and are connected to a main network switch 22 and a backup network switch 24 via links L1 and L2, respectively. Generally, a connection port 220 of the main network switch 22 is in a forwarding state to perform communication between the main network 10 and the chain network, and a connection port 240 of the main network switch 22 is in a blocking state and stands by as a backup for the main network switch 22. According to the polling process, the main network switch 22 periodically transmits a polling packet P2 to the chain network via link L2, and the main network switch 22 receives the polling packet P2 from the chain network via link L1. Similarly, the main network switch 22 also transmits an ACK packet P2_ACK for the polling packet P2 to the chain network via link L1, and the backup network switch 24 also receives an ACK packet P2_ACK from the chain network via link L2. If the time period during which the main network switch 22 has not received the polling packet P2 reaches a predetermined time, the main network switch 22 may determine that the backup network switch 24 has been disabled or that the network has stopped functioning due to a link down in the chained network. In this case, the main network switch 22 needs to enable link L1 so that all network devices in the chained network can connect to the network. Similarly, if the backup network switch 24 has been sending the polling packet P2 but has not received the ACK packet P2_ACK a predetermined number of times, the backup network switch 24 may determine that the main network switch 22 has been disabled or that the network has stopped functioning due to a link down in the chained network. In this case, the main network switch 22 needs to enable link L2 so that all network devices in the chained network can connect to the network.Similarly, the link switching packet LC2 and its ACK packet LC2_ACK are also transmitted through the chained network according to the link switching process 100. If the main network switch 22 transmits the link switching packet LC2 and does not receive the ACK packet LC2_ACK a predetermined number of times, the main network switch 22 may determine that the backup network switch 24 has been disabled or that the network has stopped functioning due to a link down in the chained network. In this case, the main network switch 22 needs to enable the link L1 so that all network devices in the chained network can connect to the network.

[0103] FIG. 18 is a schematic diagram of an embodiment of the present invention in which the subnetwork 20 is a chain network, illustrating the case where one link goes down in the chain network. In this case, the backup network switch 24 periodically sends a polling packet P2 to the chain network via link L2, but does not receive an ACK packet P2_ACK from the main network switch 22. Therefore, the backup network switch 24 needs to enable link L2 to ensure that all network devices in the link network are connected to the network. According to the link enabling process 50, in step 502, the backup network switch 24 first switches the state of the connection port 240 to a forwarding state. Next, the backup network switch 24 needs to notify the main network 10 and the chain network, respectively, that a topology update is required. In step 504, the backup network switch 24 sends a topology update packet TC1 to the main network 10 via the connection ports 242 and 244 according to redundancy protocol A, so that the network devices in the main network 10 can update their media access control address tables based on the topology update packet TC1. Meanwhile, in step 506, the backup network switch 24 transmits the topology update packet TC2 to the link network via the connection port 240 in accordance with the redundancy protocol B so that the network devices in the link network can update their media access control address tables based on the topology update packet TC2. This ensures communication between the chain network and the main network 10. Note that although Fig. 18 shows a case where some links in the chain network go down, the same applies to a case where the main network switch 22 goes down.

[0104] Furthermore, in the embodiment of the present invention, all control packets must be transmitted and received via a connection port connected to the main network 10 or a connection port connected to the subnetwork 20. Taking the main network switch 22 as an example, all control packets must be transmitted and received via a connection port 220 connected to the subnetwork 20 and connection ports 222 and 224 connected to the main network 10. If the main network switch 22 receives a control packet via a connection port other than the connection ports 220, 222, and 224, it may be determined that an incorrect network connection method has occurred, which may result in a network loop. In this case, the main network switch 22 switches the state of the connection port 220 to a disconnected state, continues this state for a predetermined period of time, and returns an error message. Similarly, taking the backup network switch 24 as an example, all control packets must be transmitted and received via a connection port 240 connected to the subnetwork 20 and connection ports 242 and 244 connected to the main network 10. If the backup network switch 24 receives a control packet via a connection port other than the connection ports 240, 242, and 244, it may be determined that an incorrect network connection method has occurred, which may result in a network loop. In this case, the standby network switch 24 switches the state of the connection port 240 to the disconnected state, continues this for a predetermined time, and returns an error message, thereby enabling the embodiment of the present invention to detect an incorrect network connection method.

[0105] FIG. 19 is a schematic diagram of a network device 190 according to an embodiment of the present invention. The network device 190 may be used to implement the main network switch 22 and the backup network switch 24 according to an embodiment of the present invention. As shown in FIG. 19, the network device 190 may include a processing unit 1900 and a memory unit 1902. The processing unit 1900 may be a general-purpose processor, a microprocessor, an application-specific integrated circuit (ASIC), or a combination thereof. The memory unit 1902 may be any data storage device connected to the processing unit 1900, storing program code 1904, and allowing the processing unit 1900 to read and execute the program code 1904. For example, the memory unit 1902 may be, but is not limited to, a read-only memory (ROM), a flash memory, a random access memory (RAM), a hard disk, an optical data storage device, a non-volatile storage unit, or the like. The network device 190 further includes a plurality of connection ports (not shown) for connecting a plurality of network devices between the subnetwork and the main network.

[0106] Network device 190 is used to represent elements necessary for implementing an embodiment of the present invention, and those skilled in the art may make various modifications and adjustments, without limitation. For example, if primary network switch 22 is implemented by network device 190, processes 50, 90, and 150 of the network-connected backup method are compiled into program code 1904 and stored in storage unit 1902, and the network-connected backup method is executed by processing unit 1900. If standby network switch 24 is implemented by network device 190, processes 50, 80, and 160 of the network-connected backup method are compiled into program code 1904 and stored in storage unit 1902, and the network-connected backup method is executed by processing unit 1900. In addition, storage unit 1902 is also used to store data necessary for executing the network-connected backup method, without limitation.

[0107] As described above, the network interconnection architecture, network switch, and backup method according to the present invention enable interconnected networks to connect and communicate with each other even when they are operating according to different redundancy protocols, thereby achieving stable performance without interfering with each other. Here, network switches can monitor network status and exchange information to achieve backup purposes through control packets, such as polling packets, connection confirmation packets, and link switching packets. By transmitting topology update packets of different redundancy protocols to each network, updated information for each network link can be notified without affecting the operation of each redundancy protocol. Furthermore, when connecting chained networks, a monitoring and backup mechanism for the chained network can be achieved by changing the transmission direction of polling packets and link switching packets. This overcomes the drawbacks of the prior art.

[0108] The above describes the preferred embodiment of the present invention, but all equivalent modifications and variations based on the claims of the present invention fall within the scope of the present invention. [Explanation of symbols]

[0109] A to D: Redundancy protocols 1: Network system 10: Main network 12_1~12_3: Subnetwork 14_1~14_3: Main network switches 16_1~16_3: Standby network switches N1~N3: Network L1~L6: Link 20: Subnetwork 22: Main network switch 24: Standby network switch 26, 28: Network switch 220, 222, 224, 240, 242, 244: Connection ports 30: Process 300~314: Step P1: Polling packet P1_ACK: ACK packet for polling packet 50: Process 500~508: Step TC1, TC2: Topology update packets 80, 90, 100: Process 800~812, 900~912, 1000~1018: Step LC1: Link switching packets LC1_ACK: ACK packet for link switching packet LT1: Link Confirmation Packet LT1_ACK: ACK packet for link confirmation packet 150, 160: Process 1500~1526, 1600~1616: Step P2: Polling packet P2_ACK: ACK packet for polling packet LC2: Link switching packets LC2_ACK: ACK packet for link switching packets 190: Network equipment 1900: Processing section 1902: Storage section 1904: Program code

Claims

1. A main network switch configured in a main network operating under a first redundancy protocol and used to couple a sub-network operating under a second redundancy protocol, comprising: at least one first connection port for connecting to said main network; a second connection port for connecting to the sub-network; a processing unit for executing program code; a storage unit connected to the processing unit, the storage unit storing program code for instructing the processing unit to execute a backup method for network connection; The backup method includes: transmitting a first control packet via the at least one first connection port; receiving an ACK packet for the first control packet when the first control packet is transmitted; when receiving the ACK packet of the first control packet, switching a state of the second connection port, transmitting a second control packet according to the first redundancy protocol through the at least one first connection port to update a media access control address table (MAC address table) of the primary network, and transmitting a third control packet according to the second redundancy protocol through the second connection port to update a media access control address table of the sub-network; The primary network switch does not perform backup according to the operation mechanism of the second redundancy protocol.

2. 2. The main network switch according to claim 1, wherein when the processing unit instructs the program code to execute the backup method, if the link of the second connection port becomes invalid (link-down), the state of the second connection port is switched to a blocking state.

3. 2. The main network switch according to claim 1, wherein, when the processing unit instructs the program code to execute the backup method, if a main line switching condition is satisfied, the state of the second connection port is switched to a forwarding state, and after transmitting a fourth control packet via the second connection port, if the fourth control packet has been received via the at least one first connection port or a timer has expired, the main network switch transmits the first control packet via the at least one first connection port.

4. 4. The main network switch of claim 3, wherein the main line switching condition is that the link of the second connection port resumes operation (link-up) or all links of the at least one first connection port become invalid.

5. The backup method includes: receiving a fifth control packet from a standby network switch in the primary network that connects to the sub-network; The main network switch of claim 3 , further comprising: upon receipt of the fifth control packet, transmitting an ACK packet for the fifth control packet.

6. 6. The main network switch according to claim 5, wherein the main line switching condition is that a time period during which the fifth control packet has not been received has reached a predetermined time period.

7. The main network switch of claim 5 , wherein the ACK packets for the first control packet and the fifth control packet are transmitted over the sub-network via the second connection port.

8. The main network switch of claim 7 , wherein the sub-network is a chain network.

9. 9. The main network switch according to claim 8, wherein the main line switching condition is that a time during which the fifth control packet has not been received has reached a predetermined time, or that the ACK packet for the first control packet has not been received after the first control packet has been transmitted.

10. further comprising a third communication port; The backup method includes:

2. The main network switch of claim 1, further comprising: when the main network switch receives any control packet via the third communication port, switching the state of the second connection port to a blocking state, maintaining this state for a predetermined time, and returning an error message.

11. A standby network switch configured in a primary network operating under a first redundancy protocol and used to connect a sub-network operating under a second redundancy protocol, at least one first connection port for connecting to said main network; a second connection port for connecting to the sub-network; a processing unit for executing program code; a storage unit connected to the processing unit, the storage unit storing program code for instructing the processing unit to execute a backup method for network connection; The backup method includes: switching the state of the second connection port; transmitting first control packets via the at least one first connection port according to the first redundancy protocol to update a media access control address table (MAC address table) of the primary network, and transmitting second control packets via the second connection port according to the second redundancy protocol to update a media access control address table of the sub-network; The standby network switch does not perform backup according to the operation mechanism of the second redundancy protocol.

12. 12. The standby network switch of claim 11, wherein when the processing unit receives a third control packet when instructed by the program code to execute the backup method, the standby network switch transmits an ACK packet for the third control packet via the at least one first connection port, and switches the state of the second connection port to a blocking state or a forwarding state.

13. 13. The standby network switch of claim 12, wherein the ACK packet of the third control packet is transmitted over the sub-network via the second connection port.

14. The standby network switch of claim 13 , wherein the sub-network is a chain network.

15. 12. The standby network switch according to claim 11, wherein when the processing unit instructs the program code to execute the backup method, if all links of the at least one first connection port become invalid, the state of the second connection port is switched to a forwarding state.

16. When the processing unit instructs the execution of the backup method by the program code stored in the storage unit, periodically transmitting a fourth control packet via the at least one first connection port; 12. The standby network switch of claim 11, further comprising: executing the backup method and switching the state of the second connection port to a forwarding state when a number of times in the main network that an ACK packet for the fourth control packet has not been received from a main network switch connected to the sub-network reaches a predetermined number.

17. 17. The standby network switch of claim 16, wherein a fourth control packet is transmitted over the sub-network via the second connection port.

18. 20. The standby network switch of claim 17, wherein the sub-network is a chain network.

19. further comprising a third communication port; 12. The standby network switch of claim 11, wherein when the standby network switch receives any control packet via the third communication port, the standby network switch switches the state of the second connection port to a disconnected state, continues this state for a predetermined time, and returns an error message.

20. A network architecture for network interconnection, comprising: a sub-network operating according to a first redundancy protocol; a primary network operating according to a second redundancy protocol; a main network switch provided in the main network, the main network switch being connected to the main network via at least one first connection port and connected to the sub-network via a second connection port; a standby network switch provided in the main network, connected to the main network via at least one third connection port and connected to the sub-network via a fourth connection port; the primary network switch and the backup network switch perform a network connection backup method; The backup method includes: the primary network switch transmitting a first control packet via the at least one first connection port; When the first control packet is received, the backup network switch transmits an ACK packet for the first control packet to switch the link, transmits a second control packet via the at least one third connection port according to the second redundancy protocol to update a media access control address table (MAC address table) of the primary network, and transmits a third control packet via the fourth connection port according to the first redundancy protocol to update a media access control address table of the sub-network; when receiving the ACK packet for the first control packet, the main network switch switches links, and sends a fourth control packet through the at least one first connection port according to the second redundancy protocol to update a media access control address table of the main network, and sends a fifth control packet through the second connection port according to the first redundancy protocol to update a media access control address table of the sub-network; A network architecture, wherein the primary network switch and the standby network switch do not perform backup according to an operation mechanism of the first redundancy protocol.

21. 21. The network architecture of claim 20, wherein when the main network switch and the backup network switch execute the backup method, if a link of the second connection port of the main network switch becomes invalid (link-down), the link is switched.

22. 21. The network architecture of claim 20, wherein when the main network switch and the standby network switch execute the backup method, if a main line switching condition is met, the main network switch transmits the first control packet via the at least one first connection port after transmitting a sixth control packet via the second connection port, or if a timer expires, the main network switch receives the sixth control packet via the at least one first connection port.

23. 23. The network architecture of claim 22, wherein the main line switching condition is that a link of the second connection port resumes operation (link-up) or all links of the at least one first connection port become invalid.

24. the standby network switch periodically transmits a seventh control packet via the at least one third connection port; 23. The network architecture of claim 22, wherein the main network switch, upon receipt of the seventh control packet, transmits an ACK packet for the seventh control packet.

25. 25. The network architecture of claim 24, wherein the main line switching condition is that the main network switch has not received the seventh control packet for a predetermined period of time.

26. the ACK packets for the first control packet and the seventh control packet are transmitted over the sub-network via the second connection port; 25. The network architecture of claim 24, wherein the ACK packet for the first control packet and the seventh control packet are transmitted over the sub-network via the fourth connection port.

27. 27. The network architecture of claim 26, wherein the sub-network is a chain network.

28. 28. The network architecture of claim 27, wherein the main line switching condition is that a time during which the main network switch has not received the seventh control packet has reached a predetermined time, or that an ACK packet for the first control packet has not been received after the first control packet has been transmitted.

29. 25. The network architecture of claim 24, wherein the standby network switch executes the backup method and switches the state of the fourth connection port to a forwarding state when the standby network switch does not receive an ACK packet for the seventh control packet from the primary network switch a predetermined number of times.

30. 25. The network architecture of claim 24, wherein the standby network switch switches the state of the fourth connection port to a forwarding state when all links of the at least one third connection port become disabled.

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