Multi-instance single-ring topology adjustment method and network switch

Abstract

This paper proposes a multi-instance single-ring topology adjustment method and a network switch. Each instance of the single-ring network has a different spare connection port, which is defaulted to an isolated state. Thus, when a link in the single-ring network fails, the topology of each instance is adjusted by changing the spare connection port of each instance to a forwarding state.

Description

[Technical Field]

[0001] This case relates to network topology technology, and in particular to a multi-instance single-ring topology adjustment method and a network switch. [Previous Technology]

[0002] In network technology, Spanning Tree Protocol (STP) is an important technology for switches, designed to avoid various problems caused by network loops. However, traditional STP technology takes 30 seconds to complete the network topology construction before data can be transmitted. When the network topology changes, STP technology takes another 30 seconds to return to a stable state, making its construction time quite lengthy. Therefore, predecessors improved STP technology and proposed Rapid Spanning Tree Protocol (RSTP). However, Rapid STP still takes 2-3 seconds to complete / reconstruct the network topology. For the current data volume of network transmission, Rapid STP still results in a significant loss of data. [Summary of the Invention]

[0003] This invention proposes a multi-instance single-ring topology adjustment method applied to a single-ring network. The single-ring network includes a plurality of network switches connected in a ring. Each network switch includes two control ports, and every two adjacent network switches are interconnected via corresponding control ports. One of these network switches is a standby switch, and the remaining network switches are standard switches. The multi-instance single-ring topology adjustment method includes: in a first network instance, a first connection port of a backup switch with two control connection ports is preset to an isolated state; in a second network instance, a second connection port of a backup switch with two control connection ports is preset to an isolated state; in response to an anomaly in a link in the single-ring network, the network switch connected to the link sends a recovery control packet, such that the recovery control packet is transmitted to the backup switch via the single-ring network; and in response to receiving the recovery control packet, the backup switch sets the first connection port in the isolated state in the first network instance to a forwarding state, and sets the second connection port in the isolated state in the second network instance to a forwarding state.

[0004] This application further proposes a network switch, including two control ports and a processing circuit. The processing circuit is coupled to the two control ports and performs the following steps. First, it determines whether either of the two control ports is preset to an isolated state in a network instance. If so, it determines that it is a standby switch in the network instance; otherwise, it determines that it is a standard switch in the network instance. If it determines that it is a standard switch in the network instance, it performs the following judgment logic, including: determining whether an anomaly is detected in a link connected to either control port. If so, it sets the control port connected to the abnormal link to an isolated state and sends a recovery control packet via the other control port according to the network instance. If it determines that it is a standby switch in the network instance, it performs the following judgment logic, including: determining whether a recovery control packet is received in the network instance. If so, it sets the control port in the isolated state in the network instance to a forwarding state; and sends a recovery control packet to the controller via a redirection port.

[0005] According to the multi-instance single-ring topology adjustment method and network switch proposed in some embodiments of this case, different backup connection ports are configured for different network instances, so that the virtual area network traffic under each network instance can be distributed by passing through different paths. In addition, when a link anomaly occurs, each network instance sends control packets to adjust and restore the topology. Furthermore, in some embodiments, blocking control packets and restoration control packets from being forwarded to the controller via redirection ports can further dynamically adjust the data path according to the link condition.

Implementation Method

[0007] Figure 1 is a block diagram of one embodiment of the network switch 10 according to this invention. Referring to Figure 1, the network switch 10 includes a processing circuit 101 and a plurality of control ports 102. Figure 1 shows an example of a network switch 10 including two control ports 102, but this invention is not limited thereto, and the network switch 10 may also include other ports.

[0008] Control port 102 is preset to be in a forwarding state or a blocking state. Processing circuit 101 is coupled to control port 102 and can set the state of control port 102 to a forwarding state or a blocking state. When network switch 10 is in a single loop network (or single-ring network), if control port 102 is in the forwarding state, control port 102 can receive data packets transmitted by the previous network switch 10 in the single loop network, and can forward data packets received by other control ports 102 to the next network switch 10 in the single loop network. In other words, control port 102 in the forwarding state can receive data packets and forward data packets. If control port 102 is in an isolated state, it can receive data packets transmitted by the previous network switch 10, but will not forward the data packets to the next network switch 10 via other control ports 102. In other words, control port 102 in an isolated state can receive data packets but will not forward them.

[0009] Accordingly, by setting the control connection port 102 to a forwarding state or an isolation state through the processing circuit 101, the control connection port 102 of the network switch 10 can be connected to the connection port of other identical network switches 10 through the transmission line. Other network switches 10 can also set their control connection port 102 to a forwarding state or an isolation state to form a single-loop network between the network switch 10 and other network switches 10 to avoid the occurrence of network topology loop.

[0010] In this document, a network switch 10 with a control connection port 102 preset to an isolated state is referred to as a backup switch, and a network switch 10 without a control connection port 102 preset to an isolated state (i.e., all its control connection ports 102 are preset to a forwarding state) is referred to as a normal switch. The control connection port 102 preset to an isolated state can also be referred to as a spare connection port.

[0011] Referring to Figure 2, it is a block diagram of one embodiment of the single-ring network according to this case. This embodiment has four aforementioned network switches 10 (i.e., network switches 1-4), which are connected in a ring to form a single-ring network. Each pair of adjacent network switches 1-4 are interconnected via corresponding control connection ports 11A-14A and 11B-14B. The processing circuits 11-14 of these network switches 1-4 are configured to preset the corresponding control connection ports 11A-14A and 11B-14B to either a forwarding state or an isolation state. This single-ring network is applied to multiple network instances. In each network instance, one of all control connection ports 11A-14A and 11B-14B in the single-ring network is preset to an isolation state (i.e., set as a spare connection port), and the control connection ports 102 preset to the isolation state are different in different network instances. Each network instance can support one or more Virtual Local Area Networks (VLANs). Since the control ports 102 in each network instance are pre-set to be isolated, the traffic transmission paths of the VLANs under each network instance are different, thus distributing the traffic.

[0012] As shown in Figure 2, in some embodiments, network switch 1 has another connection port (hereinafter referred to as redirect port 21), which connects to controller 26 and network device 27 via hub 25; network switch 3 has another connection port 22, which connects to network device 28. Network device 27 and network device 28 can communicate with each other via a single-ring network. The network device and controller 26 can be terminal devices such as computers, mobile phones, tablets, and servers. In some embodiments, network switch 1 may have other connection ports (not shown) to connect to network device 27, and this embodiment is not limited to connecting network device 27 via redirect port 21.

[0013] Referring to Figures 3A and 3B, these are schematic diagrams showing the initial states of a single-ring network in a first network instance and a second network instance, respectively, according to an embodiment of this case. For example, in the first network instance, the control port 11A of the network switch 1 is preset to an isolated state, and the remaining control ports 12A-14A and 11B-14B are preset to a forwarding state (as shown in Figure 3A); in the second network instance, the control port 11B of the network switch 1 is preset to an isolated state, and the remaining control ports 11A-14A and 12B-14B are preset to a forwarding state (as shown in Figure 3B).

[0014] In this document, filled-in blocks represent control connection ports 102 in an isolated state, and hollow blocks represent control connection ports 102 in a forwarding state. After establishing a single-ring network, network switches 1 to 4 can transmit data packets to each other, and none of network switches 1 to 4 will retransmit the data packets it sent. For example, taking Figure 3B as an example, network switch 1 transmits data packets via control connection port 11A. After the data packets pass through network switches 2, 3, and 4 in sequence, they will be returned by network switch 4 to the isolated control connection port 11B of network switch 1, and the data packets will no longer be forwarded.

[0015] In addition to forwarding data packets, network switches 10 with all control ports 102 in forwarding state also forward control packets. That is, when one control port 102 of network switch 10 receives a control packet, it forwards the control packet through another control port 102. The control packets may include forward control frames (FF), recovery control frames (RF), and block control frames (BF). These control packets are used to readjust and restore the network topology of a single-ring network, which will be explained later. Although control ports 102 in block state do not forward control packets (i.e., they do not transmit control packets received by another control port 102 through the control port 102 in block state), they can still receive control packets and can also actively send control packets.

[0016] Refer to Figure 4, which is a flowchart (I) of a multi-instance single-loop topology adjustment method according to an embodiment of this case.

[0017] Step S61: As shown in FIG3A, in the first network instance, one of the two control connection ports 102 of the standby switch (here, network switch 1) is preset to an isolated state.

[0018] Step S62: As shown in Figure 3B, in the second network instance, one of the two control connection ports 102 of the standby switch (here, network switch 1) is preset to an isolated state. It can be seen that the two network instances use different control connection ports 102 set to an isolated state. Therefore, when a data packet sent by network device 27 is transmitted to network device 28 via a single-ring network, the data packet will be transmitted along the first path P1 in the first network instance (as shown in Figure 3A), and along the second path P2 in the second network instance (as shown in Figure 3B). That is, packets transmitted to a destination device (such as the aforementioned network device 28) via a single-ring network are transmitted along different paths (first path P1, second path P2) in the first and second network instances, respectively.

[0019] Step S63: In response to an anomaly occurring in a link of the single-ring network, the network switch 10 connected to that link sends a recovery control packet RF, which is then transmitted to the backup switch via the single-ring network. Referring to Figures 5A and 5B, which are schematic diagrams illustrating anomalies in a first and second network instance of a single-ring network according to an embodiment of this invention, the following example illustrates an anomaly occurring in the link between network switch 2 and network switch 3. Network switch 2 detects the link anomaly via control port 12A and sends a recovery control packet RF via another control port 12B. Similarly, network switch 3 detects the link anomaly via control port 13B and sends a recovery control packet RF via another control port 13A. In this document, the control port 102 connecting the abnormal link is also referred to as the abnormal port, and the network switch 10 that detects the link anomaly is referred to as the abnormal switch. The recovery control packet RF is forwarded by other network switches 10 and finally transmitted to network switch 1 (the backup switch). It should be noted that the recovery control packet RF is sent in both the first network instance and the second network instance.

[0020] The link anomaly may be, for example, a physical layer anomaly such as damage to control port 12A or control port 13B, damage to the transmission line between control port 12A and control port 13B, or the transmission line becoming disconnected from control port 12A or control port 13B. However, this application is not limited to this; the anomaly may also be a traffic congestion anomaly, in which case the abnormal link in the two network instances may be in different locations, or one network instance may experience an anomaly while the other network instance does not.

[0021] In some embodiments, the link anomaly may occur at a network switch 10, for example, if network switch 3 fails. In this case, the control port 12A of network switch 1 connected to network switch 2 and the control port 14B of network switch 4 are abnormal ports. Network switches 2 and 4 that detect the link anomaly are referred to as abnormal switches. To avoid making this document too lengthy, this document will use the link anomaly between network switch 2 and network switch 3 as an example to illustrate the subsequent processing. Those skilled in the art should be able to apply this analogy to the situation where a network switch 10 malfunctions, and will not elaborate further.

[0022] Step S64: As shown in Figures 6A and 6B, in response to receiving the recovery control packet RF, the standby switch (here, network switch 1) sets the first connection port (control connection port 11A) which is in a blocked state in the first network instance to a forwarding state, and sets the second connection port (control connection port 11B) which is in a blocked state in the second network instance to a forwarding state. Figures 6A and 6B are schematic diagrams of alternative topologies of a single-ring network in the first and second network instances according to an embodiment of this invention. Here, the control connection ports 11A and 11B, which were originally in a blocked state, are used as standby connection ports. By switching the standby connection ports to a forwarding state, the single-ring network is readjusted and can be restored to normal operation.

[0023] In some embodiments, a standby switch (here, network switch 1) has a redirection port 21, which, in response to receiving a recovery control packet RF, transmits the recovery control packet RF to the controller 26 via the redirection port 21. The recovery control packet RF is generated with faulty switch information and faulty port information included. Specifically, the recovery control packet RF sent by network switch 2 includes: faulty switch information corresponding to network switch 2, and faulty port information corresponding to control port 12A. Similarly, the recovery control packet RF sent by network switch 3 includes: faulty switch information corresponding to network switch 3, and faulty port information corresponding to control port 13B. Thus, the controller 26, through the abnormal switch information and abnormal port information received in the recovery control packet RF, can know that the topology of the single-ring network has changed, and can determine which one or more network switches 10 are abnormal, and which one or more control ports 102 are abnormal. Therefore, the controller 26 can dynamically adjust the settings of each network switch 10 in the single-ring network based on the abnormal switch information and abnormal port information, changing a first route including the abnormal link to a second route that does not include the abnormal link. This change is performed at the second layer, namely the Data Link Layer. For example, the first route in the second network instance is network switch 1-2-3, and the second route in the changed second network instance is network switch 1-4-3. Each network switch 10 stores a static forwarding database, and the controller 26 is responsible for setting the entries in each static forwarding database to implement the aforementioned route change.

[0024] Referring to Table 1, the forwarding entries of the network switch 10 shown in Figures 3A and 3B (i.e., the initial state) are displayed. For example, in the first network instance, when the network switch 1 receives a data packet destined for the address of network device 27, it forwards the data packet out via redirection port 21; when the network switch 1 receives a data packet destined for the address of network device 28, it forwards the data packet out via control port 11B.

[0025] Table 1 Network switch MAC address Connector Port First Network Instance Network Switch 1 Address of network device 27 twenty one Address of network device 28 11B Network Switch 4 Address of network device 27 14A Address of network device 28 14B Network Switch 3 Address of network device 27 13A Address of network device 28 twenty two Second Network Instance Network Switch 1 Address of network device 27 twenty one Address of network device 28 11A Network Switch 2 Address of network device 27 12B Address of network device 28 12A Network Switch 3 Address of network device 27 13B Address of network device 28 twenty two

[0026] Referring to Table 2, the forwarding entries of the network switch 10 shown in Figures 6A and 6B (i.e., alternative topologies) are displayed.

[0027] Table 2 Network switch MAC address Connector Port First Network Instance Network Switch 1 Address of network device 27 twenty one Address of network device 28 11B Network Switch 4 Address of network device 27 14A Address of network device 28 14B Network Switch 3 Address of network device 27 13A Address of network device 28 twenty two Second Network Instance Network Switch 1 Address of network device 27 twenty one Address of network device 28 11B Network Switch 4 Address of network device 27 14A Address of network device 28 14B Network Switch 3 Address of network device 27 13A Address of network device 28 twenty two

[0028] Refer to Figures 7, 8A, and 8B. Figure 7 is a flowchart (II) of a multi-instance single-ring topology adjustment method according to an embodiment of this invention. Figures 8A and 8B are schematic diagrams of link restoration of a single-ring network in the first network instance and the second network instance, respectively, according to an embodiment of this invention.

[0029] Step S71: In response to a link restoration, network switches 2 and 3 connected to the link send an isolation control packet BF, which is transmitted to the backup switch (in this case, network switch 1) via a single-ring network. Specifically, the isolation control packet BF is sent via another control port 12B and 13A, which is different from the aforementioned abnormal control ports 12A and 13B.

[0030] Step S72: In response to receiving the blocking control packet BF, the standby switch (here, network switch 1) sets the first connection port (control connection port 11A) in the first network instance to the blocking state (as shown in Figure 8A), and sets the second connection port (control connection port 11B) in the second network instance to the blocking state (as shown in Figure 8B).

[0031] Refer to Figures 7, 9A and 9B. Figures 9A and 9B are topological reconstruction diagrams of a single-ring network in a first network example and a second network example, respectively, according to an embodiment of this case.

[0032] Step S73: After completing the blocking state setting, the standby switch (here, network switch 1) sends a forwarding control packet FF, which is transmitted via a single-ring network to network switches 2 and 3 connected to the link. Specifically, the forwarding control packet FF is sent via two control ports 11A and 11B.

[0033] Step S74: In response to receiving the forwarding control packet FF, network switches 2 and 3 connected to the link set the control ports 12A and 13B connected to the link to forwarding mode. Thus, the network topology of the single-ring network is restored to the state before the anomaly occurred.

[0034] In some embodiments, as shown in Figures 8A and 8B, the standby switch also transmits the isolation control packet BF to the controller 26 via the redirection port 21. The isolation control packet BF is generated with recovery switch information and recovery port information included. Specifically, the isolation control packet BF sent by network switch 2 includes: recovery switch information corresponding to network switch 2, and recovery port information corresponding to control port 12A. Similarly, the isolation control packet BF sent by network switch 3 includes: recovery switch information corresponding to network switch 3, and recovery port information corresponding to control port 13B. Thus, the controller 26, through the recovery switch information and recovery port information in the received isolation control packet BF, can know that the topology of the single-ring network has changed, and can know which one or more network switches 10 have recovered from their anomalies, and which one or more control ports 102 have recovered from their anomalies. Therefore, the controller 26 can dynamically adjust the settings of each network switch 10 in the single-ring network based on the restored switch information and restored port information, so as to change the second route that previously did not include the restored link to the first route that includes the restored link. The change is performed at the second layer, namely the Data Link Layer. For example, the first route in the second network instance is network switch 1-2-3, and the second route in the second network instance is network switch 1-4-3. Each network switch 10 stores a static forwarding database, and the controller 26 is responsible for setting the entries in each static forwarding database to realize the aforementioned route change. When the topology is restored, the forwarding entries of the network switch 10 are shown in Table 1.

[0035] Next, to facilitate the implementation of the single-ring network of the aforementioned embodiments, the execution program of each network switch 10 constituting the single-ring network will be described. Referring to FIG10, it is a flowchart of the initialization program of the network switch 10 of some embodiments of this invention. First, in step S31, the processing circuit 101 loads setting parameters. The setting parameters may be stored in a parameter file to set each control connection port 102 to a forwarding state or a blocking state. In some embodiments, the processing circuit 101 has a memory to store the parameter file. In some embodiments, the processing circuit 101 is coupled to an external memory to read the parameter file stored in the external memory. After step S31, step S32 is executed, in which the processing circuit 101 determines whether there is a control connection port 102 in a blocking state in each network instance. If not, the processing circuit 101 determines that the network switch 10 is a standard switch in the network instance, i.e., step S33; if yes, the processing circuit 101 determines that the network switch 10 is a standby switch in the network instance, i.e., step S34. After steps S33 and S34, the processing circuit 101 will send a forwarding control packet FF through two control connection ports 102 respectively, i.e., step S35.

[0036] Figure 11 is a flowchart of the execution program of the processing circuit 101 of a standard switch in some embodiments of this invention. In step S41, the processing circuit 101 determines whether an abnormality is detected in the control connection port 102 of the network instance (i.e., a link abnormality is detected). In response to the detection of the abnormality in the control connection port 102, step S42 is executed, the processing circuit 101 sets the abnormal control connection port 102 in this network instance to a blocked state, and sends a recovery control packet RF through another control connection port 102 according to this network instance. In step S43, the processing circuit 101 determines whether the abnormal connection port has been restored. After a repair operation such as maintenance, in response to the detection of the restoration of the control connection port 102 in the network instance, the processing circuit 101 executes step S44, and sends a blocking control packet BF through another control connection port 102 according to this network instance. In step S45, the processing circuit 101 determines whether a forwarding control packet FF has been received. In response to receiving a forwarding control packet FF (indicating that the standby connection port of the standby switch has switched back to the blocked state), step S46 is executed, and the processing circuit 101 sets the control connection port 102 in the blocked state in the network instance to the forwarding state.

[0037] Figure 12 is a flowchart of the execution program of the processing circuit 101 of the backup switch in some embodiments of this case. In step S51, the processing circuit 101 determines whether an abnormality is detected in the control connection port 102 of the network instance (i.e., a link abnormality is detected). If yes, step S52 is executed to determine whether the abnormal control connection port 102 of this network instance is a backup connection port. If the determination result of step S52 is no, it indicates that another control connection port 102 in the forwarding state has become abnormal (the network topology should be further adjusted and step S53 should be executed). In step S53, the processing circuit 101 sets the abnormal control connection port 102 in this network instance to an isolated state and sets the backup connection port in this network instance to a forwarding state. In this way, the single-ring network is readjusted and can be restored to normal operation. If the judgment result of step S52 is yes, then the control connection port 102 in the blocked state has malfunctioned. At this time, no processing is required because the control connection port 102 in the blocked state does not forward packets and does not affect packet transmission.

[0038] In step S54, the processing circuit 101 determines whether a recovery control packet RF is received in the network instance. In response to receiving the recovery control packet RF (indicating an anomaly in the control port 102 of another network switch 10), step S55 is executed. The processing circuit 101 sets the control port 102 (i.e., the backup port) in the network instance that is in a blocked state to a forwarding state. If the backup switch has a redirection port 21, the recovery control packet RF is sent via the redirection port 21. Here, the control port 102, which was originally in a blocked state, is used as a backup port. By switching the backup port to a forwarding state, the single-ring network is readjusted and can resume normal operation.

[0039] In step S56, the processing circuit 101 determines whether a blocking control packet BF is received in the network instance. In response to receiving a blocking control packet BF (indicating that the control connection port 102 of another network switch 10 has recovered from an abnormality), step S57 is executed. The processing circuit 101 sets the standby connection port in this network instance to a blocking state and sends a forwarding control packet FF via the control connection port 102. If the standby switch has a redirection connection port 21, the blocking control packet BF is sent via the redirection connection port 21.

[0040] In some embodiments, the processing circuit 101 is implemented by a central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), a system on a chip (SOC), etc.

[0041] In some embodiments, the aforementioned forwarding state can be the forwarding state defined by STP, and the aforementioned blocking state can be the blocking state defined by STP. The control packet can be the BPDU defined by STP. Accordingly, network switches 11-14 can also be applied to STP and Rapid Spanning Tree Protocol (RSTP). The aforementioned network example is deployed according to Multiple Spanning Tree Protocol (MSTP).

[0042] According to the multi-instance single-ring topology adjustment method and network switch proposed in some embodiments of this case, different backup connection ports are configured for different network instances, so that the virtual area network traffic under each network instance can be distributed by passing through different paths. In addition, when a link anomaly occurs, each network instance sends control packets to adjust and restore the topology. Furthermore, in some embodiments, the blocking control packet BF and the restoration control packet RF are forwarded to the controller 26 via the redirection connection port 21, which can further dynamically adjust the data path according to the link condition. [Simplified Explanation of the Diagram]

[0006] Figure 1 is a block diagram of one embodiment of the network switch according to this case. Figure 2 is a block diagram of one embodiment of the single-ring network according to this case. Figure 3A is a schematic diagram of the initial state of the single-ring network in a first network instance according to an embodiment of this case. Figure 3B is a schematic diagram of the initial state of the single-ring network in a second network instance according to an embodiment of this case. Figure 4 is a flowchart (I) of a multi-instance single-ring topology adjustment method according to an embodiment of this case. Figure 5A is a schematic diagram of an anomaly occurring in the first network instance of the single-ring network according to an embodiment of this case. Figure 5B is a schematic diagram of an anomaly occurring in the second network instance of the single-ring network according to an embodiment of this case. Figure 6A is a schematic diagram of an alternative topology of the single-ring network in the first network instance according to an embodiment of this case. Figure 6B is a schematic diagram of an alternative topology of the single-ring network in the first network instance according to an embodiment of this case. Figure 7 is a flowchart (II) of a multi-instance single-ring topology adjustment method according to an embodiment of this case. Figure 8A is a schematic diagram of link restoration of the single-ring network in the first network instance according to an embodiment of this case. Figure 8B is a schematic diagram of link restoration of a single-ring network in a second network instance according to an embodiment of this invention. Figure 9A is a schematic diagram of topology restoration of a single-ring network in a first network instance according to an embodiment of this invention. Figure 9B is a schematic diagram of topology restoration of a single-ring network in a second network instance according to an embodiment of this invention. Figure 10 is a flowchart of the network switch initialization procedure according to some embodiments of this invention. Figure 11 is a flowchart of the execution program of the processing circuit of a standard switch according to some embodiments of this invention. Figure 12 is a flowchart of the execution program of the processing circuit of a standby switch according to some embodiments of this invention.

Claims

1. A multi-instance single-ring topology adjustment method, applied to a single-ring network, the single-ring network including a plurality of network switches connected in a ring, each network switch including two control ports, and each pair of adjacent network switches being interconnected via corresponding control ports, one of the network switches being a standby switch, and the remaining network switches being standard switches, the multi-instance single-ring topology adjustment method comprising: In a first network example, one of the two control ports of the backup switch is preset to an isolated state; In a second network instance, one of the two control ports of the backup switch is preset to the blocked state; in response to an anomaly in a link in the single-ring network, each network switch connected to the link sends a recovery control packet, such that the recovery control packet is transmitted to the backup switch via the single-ring network; and in response to receiving the recovery control packet, the backup switch sets the first port in the blocked state in the first network instance to a forwarding state, and sets the second port in the blocked state in the second network instance to the forwarding state; wherein, the recovery control packet includes abnormal switch information and abnormal port information, the abnormal switch information corresponding to the network switch connected to the abnormal link, and the abnormal port information corresponding to the control port of the network switch connected to the abnormal link; The backup switch further includes a redirection port and is connected to a controller via the redirection port. In response to receiving the recovery control packet, the backup switch also transmits the recovery control packet to the controller via the redirection port. The controller configures a static forwarding table stored by each of the network switches based on the faulty switch information and faulty port information included in the recovery control packet, so as to change a first route including the faulty link to a second route excluding the faulty link.

2. The multi-instance single-loop topology adjustment method as described in claim 1 further includes: In response to the link being restored, the network switch connected to the link sends a blocking control packet, which is transmitted to the backup switch via the single-ring network; and in response to receiving the blocking control packet, the backup switch sets the first connection port in the first network instance to the blocking state, and sets the second connection port in the second network instance to the blocking state.

3. The multi-instance single-loop topology adjustment method as described in claim 2 further includes: After completing the blocking state setting, the backup switch sends a forwarding control packet, which is transmitted via the single-ring network to the network switch connected to the link; and in response to receiving the forwarding control packet, the network switch connected to the link sets the control port connected to the link to the forwarding state.

4. The multi-instance single-ring topology adjustment method as described in claim 2, wherein the isolation control packet includes a recovery switch information and a recovery port information, the recovery switch information corresponding to the network switch connected to the link being restored, and the recovery port information corresponding to the control port of the network switch connected to the link being restored, wherein the standby switch also transmits the isolation control packet to the controller via the redirection port.

5. The multi-instance single-ring topology adjustment method as described in claim 1, wherein packets transmitted to a destination device via the single-ring network are transmitted along different paths in the first network instance and the second network instance, respectively.

6. A network switch, comprising: Two control connection ports; A processing circuit coupled to the two control ports performs the following: determining whether either of the two control ports is preset to an isolated state in a network instance; if so, determining that it is a standby switch in the network instance; if not, determining that it is a standard switch in the network instance. If the switch determines that it is the standard switch in the network instance, the following determination logic is executed, including: determining whether an anomaly is detected in a link connected to any of the control ports; if so, setting the control port connected to the anomaly link to the blocked state, and sending a recovery control packet via another control port according to the network instance; and if the switch determines that it is the backup switch in the network instance, the following determination logic is executed, including: determining whether the recovery control packet is received in the network instance; if so, setting the control port in the blocked state in the network instance to a forwarding state; and sending the recovery control packet to a controller via a redirection port; wherein the recovery control packet includes an abnormal switch information and an abnormal port information, the abnormal switch information corresponding to the network switch connected to the anomaly link, and the abnormal port information corresponding to the control port of the network switch connected to the anomaly link; The backup switch further includes a redirection port and is connected to a controller via the redirection port. In response to receiving the recovery control packet, the backup switch also transmits the recovery control packet to the controller via the redirection port. The network switch stores a static forwarding table, which is configured by the controller based on the abnormal switch information and abnormal port information included in the recovery control packet, so as to change a first route including the abnormal link to a second route excluding the abnormal link.

7. The network switch as described in claim 6, wherein the processing circuitry further performs the following determination logic if it determines that it is the standard switch in the network instance: The system determines whether a forwarding control packet has been received in the network instance. If so, it sets the control connection port in the blocked state in the network instance to the forwarding state. It also determines whether the link has been restored. If so, the network instance sends a blocking control packet via the control connection port not connected to the link. If it determines that it is the backup switch in the network instance, it sends the forwarding control packet via the two control connection ports and executes the following determination logic, including: determining whether the blocking control packet has been received in the network instance. If so, it sets the control connection port in the forwarding state in the network instance to the blocked state, sends the forwarding control packet via the other control connection port, and sends the blocking control packet to the controller via the redirection connection port.

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