Network switch and network switch system thereof

Abstract

The present application proposes a network switch and a network switch system thereof. The network switch includes a plurality of connection ports and a processing circuit. Each connection port is preset to be in an enabled state or a closed state to form a single ring network. When any connection port receives a first abnormal information packet and one of the connection ports is in a closed state, the processing circuit sets the connection port in the closed state to switch to an enabled state, and the processing circuit does not forward the first abnormal information packet in the single ring network. When one of the connection ports is abnormal and all the connection ports forming the single ring network are in an enabled state, the processing circuit sets the abnormal connection port to switch to a closed state, and transmits a second abnormal information packet to other network switches in the single ring network via another connection port that is not abnormal.

Description

Technical Field

[0001] The present application relates to a network switch and a network switch system thereof, in particular to a network switch and a network switch system thereof suitable for quickly forming a single ring network. Background Art

[0002] In network technology, spanning tree protocol (STP) technology is an important technology for switches, and its purpose is to avoid various problems caused by network loops. However, traditional STP technology takes 30 seconds to complete the construction, and data can only be transmitted after the construction is completed. When the network topology changes (topology change), STP technology takes 30 seconds to return to a stable state, and its construction time is quite lengthy. Therefore, predecessors improved STP technology and proposed Rapid Spanning Tree Protocol (RSTP) technology. However, Rapid STP technology still takes 2-3 seconds to complete / reconstruct the network topology. For the amount of data transmitted in today's network, Rapid STP will still cause a large amount of information loss. Summary of the invention

[0003] In some embodiments, a network switch includes a plurality of connection ports and a processing circuit. Each connection port is preset to be in an enabled state or a disabled state to form a single ring network. Each connection port in the enabled state receives a data packet in the single ring network and forwards the data packet, and each connection port in the disabled state receives a data packet in the single ring network and does not forward the data packet. The processing circuit is coupled to the aforementioned connection ports, and is used to determine whether the connection ports forming the single ring network are abnormal, and to determine whether any of the connection ports forming the single ring network receives a first abnormal information packet from other network switches. When any of the connection ports receives the first abnormal information packet and one of the connection ports forming the single ring network is in a closed state, the processing circuit sets the connection port in the closed state to switch to an enabled state, and the processing circuit does not forward the first abnormal information packet in the single ring network. When one of the connection ports forming the single ring network is abnormal and all of the connection ports forming the single ring network are in an enabled state, the processing circuit sets the abnormal connection port to switch to a closed state, and transmits a second abnormal information packet to other network switches in the single ring network via another connection port that is not abnormal.

[0004] In some embodiments, when any of the aforementioned connection ports receives a first exception information packet, if all the connection ports forming a single ring network are in an enabled state, the processing circuit forwards the first exception information packet to other network switches in the single ring network via another connection port that has not received the second exception information packet.

[0005] In some embodiments, a connection port in an enabled state is directly switched to a disabled state without passing through other port states, and a connection port in a disabled state is directly switched to an enabled state without passing through other port states.

[0006] In some embodiments, the other port states are a listening state, a learning state, a discarding state, or any combination thereof.

[0007] In some embodiments, after the abnormal connection port is switched to the closed state, if one of the connection ports receives a third abnormal information packet from another network switch, the processing circuit sets the abnormal connection port to remain in the closed state instead of switching to the enabled state.

[0008] In some embodiments, the aforementioned network switch and other network switches in a single ring network are not root bridges.

[0009] In some embodiments, the aforementioned processing circuit does not send BPDU defined by the spanning tree protocol in the single ring network.

[0010] In some embodiments, the processing circuit does not send the MAC address of the network switch to other network switches in the single ring network when forming a single ring network.

[0011] In some embodiments, the first abnormal information packet and the second abnormal information packet do not include the MAC address and identifier of the network switch.

[0012] In some embodiments, a network switch system includes a first network switch and a second network switch. The first network switch includes a plurality of first connection ports and a first processing circuit. The plurality of first connection ports are preset to be in an enabled state to form a single ring network and transmit data packets received from other network switches in the single ring network. The first processing circuit is coupled to the first connection port. When one of the first connection ports is abnormal and all the first connection ports forming the single ring network are in an enabled state, the first processing circuit sets the abnormal first connection port to switch to a closed state and transmits an abnormal information packet in the single ring network through another first connection port that is not abnormal. The second network switch includes a second connection port and a second processing circuit. The second connection port is preset to be in a closed state to form a single ring network and does not forward data packets received from the first network switch. The second processing circuit is coupled to the second connection port. When the second connection port receives an abnormal information packet, the second processing circuit sets the second connection port to switch from a closed state to an enabled state to form another single ring network, and the second processing circuit does not forward the abnormal information packet.

[0013] In some embodiments, the aforementioned network switch system further includes a third network switch coupled between the first network switch and the second network switch, and the third network switch includes a plurality of third connection ports and a third processing circuit. The plurality of third connection ports are preset to be in an enabled state to form a single ring network and transmit the data packets received from the first network switch to the second network switch in the single ring network. The third processing circuit is coupled to the third connection port, and when any of the third connection ports receives an abnormal information packet, the third processing circuit forwards the abnormal information packet to the second connection port via another third connection port.

[0014] In some embodiments, the first network switch, the second network switch, and the third network switch are not root bridges.

[0015] In some embodiments, the abnormal first connection port is directly switched to a closed state without going through other port states, and the second connection port in the closed state is directly switched to an enabled state without going through other port states.

[0016] In some embodiments, the port status is a listening state, a learning state, a discarding state, or any combination thereof.

[0017] In some embodiments, after the abnormal first connection port is switched to the closed state, if one of the first connection ports receives another abnormal information packet, the processing circuit sets the abnormal first connection port to remain in the closed state instead of switching to the enabled state.

[0018] In some embodiments, the first processing circuit, the second processing circuit, and the third processing circuit do not send BPDUs defined by the spanning tree protocol in a single ring network.

[0019] In some embodiments, the first processing circuit does not send the MAC address of the first network switch to the second network switch when forming a single ring network, and the second processing circuit does not send the MAC address of the second network switch to the third network switch when forming a single ring network.

[0020] In some embodiments, the aforementioned abnormal information packet does not include the MAC address and identifier of the first network switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a block diagram of an embodiment of a network switch according to the present application.

[0022] Figure 2 It is a block diagram of an embodiment of a network switch system according to the present application.

[0023] Figure 3 It is a flow chart of an embodiment of a procedure for establishing a single ring network according to the present application.

[0024] Figure 4 It is a flow chart of another embodiment of the procedure for establishing a single ring network according to the present application.

[0025] Figure 5 for Figure 2 A block diagram of an embodiment of a network switch system in operation. DETAILED DESCRIPTION

[0026] Figure 1 This is a block diagram of an embodiment of a network switch according to the present application. Figure 1 The network switch 11 includes a processing circuit 110 and a plurality of connection ports 11A, 11B, and 11C. Figure 1 The network switch 11 includes three connection ports 11A, 11B, and 11C as an example, but the present application is not limited thereto, and the number of connection ports may be greater than three.

[0027] The connection ports 11A, 11B, 11C are preset to be in an enabled state or a disabled state. The processing circuit 110 is coupled to the connection ports 11A, 11B, 11C and can set the states of the connection ports 11A, 11B, 11C to be enabled state or disabled state. When the network switch 11 is in a path of a single ring network, if the connection ports 11A, 11B, 11C are in an enabled state, the connection ports 11A, 11B, 11C can receive data packets transmitted by the previous network switch in the single ring network, and the connection ports 11A, 11B, 11C can forward the aforementioned data packets to the next network switch in the single ring network. In other words, the connection ports 11A, 11B, 11C in the enabled state can receive data packets and forward the data packets; if the connection ports 11A, 11B, 11C are in a disabled state, the connection ports 11A, 11B, 11C can receive data packets transmitted by the previous network switch, and the connection ports 11A, 11B, 11C do not forward the data packets to the next network switch. In other words, the connection ports 11A, 11B, 11C in the disabled state can receive data packets and do not forward the data packets. For example, the connection ports 11A, 11B, and 11C may be connected to electronic devices, such as cameras and computers. Taking a camera as an example, the aforementioned data packets may be image data.

[0028] Based on this, by setting the connection ports 11A, 11B, and 11C to an enabled state or a disabled state through the processing circuit 110, the connection ports 11A, 11B, and 11C of the network switch 11 can be connected to the connection ports of other identical network switches through transmission lines, and other network switches can also set their connection ports to an enabled state or a disabled state, so as to form a single ring network between the network switch 11 and other network switches to avoid a network topology loop. For example, please refer to Figure 2 , taking the example of network switch 11 connecting to other identical network switches 12-16, and Figure 2 Only the connection ports 11A-16A and 11B-16B forming a single ring network are shown as an example. Figure 2As shown, each network switch 11-16 includes a processing circuit 110-160, respectively. The processing circuits 120-160 of the network switches 12-16 can also respectively set their connection ports 12A-16A, 12B-16B to an enabled state or a disabled state (that is, the processing circuit 120 can set the connection ports 12A, 12B to an enabled state or a disabled state, the processing circuit 130 can set the connection ports 13A, 13B to an enabled state or a disabled state, and so on and so forth) to form a single ring network through the connection ports 11A-16A, 11B-16B. For example, the processing circuit 140 of the network switch 14 can set the connection port 14A to a closed state, and the processing circuits 110-130, 150, 160 of the network switches 11-13, 15, 16 can respectively set the other connection ports 11A-13A, 15A, 16A, 11B-16B to be enabled states to establish the aforementioned single ring network. After the single ring network is established, the network switches 11-16 can transmit data packets to each other, and any of the network switches 11-16 will not receive the data packets sent by itself. For example, the data packets transmitted by the network switch 13 will no longer be returned to the network switch 13 via the network switch 14.

[0029] After forming a single ring network between the network switches 11-16, if any of the connection ports 11A-11B, 12A-12B in the enabled state has an abnormality, the abnormal connection port can be automatically switched to the closed state, and the connection ports 11A-11B, 12A-12B that were originally in the closed state can be automatically switched to the enabled state, that is, the network switches 11-16 can execute the reconstruction procedure of the single ring network to change the network topology.

[0030] Please combine references Figures 1 to 4, the following first takes the network switch 11 and the connection ports 11A, 11B as an example to explain the operation of each network switch 11-16. After forming a single ring network, in order to detect whether the network topology needs to be changed, the processing circuit 110 determines whether the connection ports 11A, 11B forming the single ring network are abnormal (step S01), and the processing circuit 110 determines whether the connection ports 11A, 11B receive abnormal information packets from other network switches (step S04). In step S04, if the connection ports 11A and 11B do not receive the abnormal information packet from other network switches (the judgment result is "No"), it means that the connection ports of other network switches are normal. At this time, when the processing circuit 110 determines in step S01 that any one of the connection ports 11A and 11B is abnormal (the judgment result of step S01 is "Yes"), taking the case that the connection port 11A is abnormal and the connection ports 11A and 11B are both in the enabled state, the processing circuit 110 sets the abnormal connection port 11A to be switched from the enabled state to the closed state in the aforementioned reconstruction procedure (step S02), and the processing circuit 110 transmits the abnormal information packet to the next network switch in the single ring network via the connection port 11B that is not abnormal and is in the enabled state (step S03), so as to continue the reconstruction procedure of the single ring network.

[0031] On the other hand, if no abnormality occurs to the connection ports 11A and 11B, when the processing circuit 110 determines in step S04 that any one of the two connection ports 11A and 11B receives an abnormal information packet from the previous network switch in the single ring network, it indicates that the connection port of one of the network switches in the single ring network is abnormal. At this time, in the reconstruction procedure of the single ring network, the processing circuit 110 further determines the status of the connection ports 11A and 11B to determine whether one of the connection ports 11A and 11B is in a closed state (step S05). The processing circuit 110 then determines whether to switch the connection port in the closed state to an enabled state based on the judgment result. In other words, if the connection port of the other network switch is abnormal, the processing circuit 110 needs to set any connection port 11A and 11B in the closed state to be switched to an enabled state to establish a new single ring network. Taking the case where the connection port 11A is in the enabled state and the connection port 11B is in the disabled state as an example, the processing circuit 110 determines in step S05 that the connection port 11B is in the disabled state (the determination result of step S05 is “yes”), and the processing circuit 110 sets the second connection port 11B to be switched from the disabled state to the enabled state (step S06), and the processing circuit 110 does not forward the abnormal information packet (step S07).

[0032] On the other hand, in some embodiments, in the case where a connection port of one of the network switches in the aforementioned single ring network is abnormal so that any one of the connection ports 11A and 11B receives an abnormal information packet (the judgment result of step S04 is "yes"), if the processing circuit 110 determines in step S05 that both the connection ports 11A and 11B are in an enabled state (the judgment result is "no"), it means that the connection ports 11A and 11B can forward data packets in the re-established single ring network, and the processing circuit 110 does not need to reset the states of the connection ports 11A and 11B. The connection ports 11A and 11B are maintained in an enabled state without changing the state. The processing circuit 110 forwards the abnormal information packet to other network switches in the single ring network via the connection port of the connection ports 11A and 11B that has not received the abnormal information packet, that is, the processing circuit 110 forwards the abnormal information packet via the connection port 11A or the connection port 11B connected to the next network switch (step S08). Based on this, each processing circuit 110 - 160 executes steps S01 and S04 , and executes subsequent steps S02 - S03 , S05 - S08 according to the determination results of S01 and S04 , so as to complete the reconstruction procedure of the single ring network.

[0033] Please combine references Figures 3 to 5 Taking the case where the connection ports 11A and 16B are abnormal and the connection port 14A is in the closed state and the connection ports 11A-13A, 15A, 16A, 11B-16B are in the enabled state as an example, in step S01, the processing circuit 110 determines that the connection port 11A is abnormal (the judgment result is "yes"), and the processing circuit 160 determines that the connection port 16B is abnormal (the judgment result is "yes"), the processing circuit 110 executes step S02 to set the connection port 11A to switch from the enabled state to the closed state, and the processing circuit 160 executes step S02 to set the connection port 16B to switch from the enabled state to the closed state, the processing circuit 160 transmits the first abnormal information packet P1 to the network switch 15 via the connection port 16A (step S03), and the processing circuit 110 transmits the second abnormal information packet P2 to the network switch 12 via the connection port 11B (step S03).

[0034] Therefore, the processing circuit 120 of the network switch 12 determines in step S04 that the connection port 12A receives the second abnormal information packet P2 from the network switch 11 (the judgment result is "yes"), and the processing circuit 120 determines in step S05 that the connection ports 12A and 12B are both in the enabled state and not in the disabled state (the judgment result is "no"), and the processing circuit 120 does not switch the states of the connection ports 12A and 12B, and the processing circuit 120 forwards the second abnormal information packet P2 to the network switch 13 via the connection port 12B (step S08). Therefore, the processing circuit 130 of the network switch 13 determines in step S04 that the connection port 13A receives the second abnormal information packet P2 from the network switch 12 (the judgment result is "yes"), and the processing circuit 130 then determines in step S05 that the connection ports 13A and 13B are both in the enabled state and not in the disabled state (the judgment result is "no"), the processing circuit 130 does not switch the states of the connection ports 13A and 13B, and the processing circuit 130 forwards the second abnormal information packet P2 to the network switch 14 via the connection port 13B (step S08). Similarly, after the network switch 16 sends the first abnormal information packet P1, the processing circuit 150 of the network switch 15 determines in step S04 that the connection port 15B receives the first abnormal information packet P1 from the network switch 16 (the judgment result is "yes"), and the processing circuit 150 determines in step S05 that the connection ports 15A and 15B are both in the enabled state and not in the closed state (the judgment result is "no"), the processing circuit 150 does not switch the state of the connection ports 15A and 15B, and the processing circuit 150 forwards the first abnormal information packet P1 to the network switch 14 via the connection port 15A (step S08).

[0035] Based on this, the processing circuit 140 of the network switch 14 determines in step S04 that the connection port 14B receives the first abnormal information packet P1 and determines that the connection port 14A receives the second abnormal information packet P2 (the judgment result is "yes"). The processing circuit 140 determines in step S05 that the connection port 14A is in a closed state. Therefore, the processing circuit 140 sets the connection port 14A to switch from a closed state to an enabled state (step S06) to establish a new single ring network. The processing circuit 140 does not forward the first abnormal information packet P1 to the network switch 13 and does not forward the second abnormal information packet P2 to the network switch 15 (step S07). In this way, the reconstruction procedure of the single ring network is completed.

[0036] In some embodiments, taking the network switch 11 as an example, when any of the connection ports 11A and 11B is abnormal, the processing circuit 110 can store abnormal information, waiting for the administrator or user of the network switch 11 to perform maintenance on the abnormal condition.

[0037] In some embodiments, the network switch 11-16 can automatically set the status of the connection ports 11A-16A and 11B-16B to an enabled state or a disabled state according to the user's settings after powering on, so that the single ring network is established. Based on this, in the process of establishing and rebuilding the single ring network, the network switches 11-16 do not perform the root bridge determination procedure, that is, when forming a single ring network, the network switches 11-16 do not transmit their Media Access Control Address (MAC) and identifier (ID) to each other to determine the root bridge, and the network switches 11-16 do not need to determine each connection port 11A-16A, 11B-16B as a root port, a designated port, or an alternate port based on the aforementioned MAC address and identifier, which can greatly improve the speed of establishing a single ring network.

[0038] Furthermore, after the single ring network is established, when the connection ports 11A and 16B are abnormal and the network topology needs to be changed, the connection ports 11B and 16A transmit the abnormal information packets P2 and P1 to the next network switches 12 and 15 respectively. The abnormal information packets P2 and P1 do not contain the MAC addresses and identifiers of the network switches 11 and 16. The next network switches 12 and 15 that receive the abnormal information packets P2 and P1 then forward the abnormal information packets P2 and P1 until the abnormal information packets P2 and P1 are forwarded to the network switch 14 with the connection port 14A in the closed state, and then stop forwarding the abnormal information packets P2 and P1. In other words, in the process of rebuilding the single ring network, the network switch with the abnormality among the network switches 11-16 will not transmit the information packet to the root bridge, and then the root bridge will notify other network switches, which can greatly improve the reconstruction speed of the single ring network.

[0039] In some embodiments, the network switches 11 - 16 do not periodically exchange Bridge Protocol Data Units (BPDUs) defined in the Spanning Tree Protocol (Spanning Tree Protocol; STP), which can reduce the amount of data exchange between the network switches 11 - 16 . Furthermore, when the network switch 11-16 switches the port status of the connection ports 11A-16A, 11B-16B, the connection ports 11A-16A, 11B-16B are set to switch directly from the closed state to the enabled state, or from the enabled state to the closed state. That is, when the connection ports 11A-16A, 11B-16B are switched from the closed state to the enabled state or from the enabled state to the closed state, they are not directly switched to the closed state or the enabled state via other port states (for example, listening state, learning state and discarding state). That is, each connection port 11A-16A, 11B-16B does not need to wait for BPDU to switch its port status, thereby speeding up the reconstruction speed of a single ring network.

[0040] In some embodiments, the aforementioned enabled state may be a forwarding state defined by STP, and the aforementioned disabled state may be a blocking state defined by STP, and the abnormal information packets P1 and P2 may be BPDUs defined by STP. Based on this, the network switches 11-16 may also be applicable to STP and Rapid Spanning Tree Protocol (RSTP).

[0041] In some embodiments, the connection port 11A is connected to the connection port 16B via a transmission line L. When the connection between the transmission line L and the connection ports 11A and 16B is disconnected, the transmission line L is damaged, or the connection ports 11A and 16B themselves are damaged, resulting in the inability to normally transmit data packets between the network switches 16 and 11, the processing circuit 110 can determine that the connection port 11A is abnormal in step S01, and the processing circuit 160 can determine that the connection port 16B is abnormal in step S01.

[0042] In some embodiments, taking the network switch 11 as an example, after the abnormal connection port 11A is switched to the closed state, if the connection ports 11A and 11B of the network switch 11 receive abnormal information packets from other network switches 12-16, the processing circuit 110 sets the abnormal connection port 11A to remain in the closed state instead of switching to the enabled state, so as to avoid the abnormal connection port 11A switching to the enabled state and failing to transmit data packets normally. Similarly, taking the network switch 16 as an example, after the abnormal connection port 16B is switched to the closed state, if the connection ports 16A and 16B of the network switch 16 receive abnormal information packets from other network switches 11-15, the processing circuit 160 sets the abnormal connection port 16B to remain in the closed state instead of switching to the enabled state, so as to avoid the abnormal connection port 16B switching to the enabled state and failing to transmit data packets normally.

[0043] In summary, according to an embodiment of the network switch and the network switch system of the present application, in the process of establishing a single ring network, the network switches save the root bridge determination procedure, and the network switches do not need to determine the role of the connection port through the MAC address and identification code of the network switch. Therefore, when the network topology needs to be changed, the network switch does not need to notify other network switches through the root bridge, and a single ring network can be quickly established. Different from the STP technology and the RSTP technology, the network switch system can complete the construction of a single ring network within 1 ms, and the amount of data lost by the users of the network switch can be minimized.

[0044] Although the present application has been disclosed as above with embodiments, they are not intended to limit the present application. Any person skilled in the art may make some changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be determined by the attached patent application claims.

[0045]

Explanation of symbols

[0046] 11-16: Network switch

[0047] 110-160: Processing circuit

[0048] 11A-16A: Connection port

[0049] 11B-16B: Connection port

[0050] 11C: Connection port

[0051] L: Transmission line

[0052] P1: The first abnormal information packet

[0053] P2: The second abnormal information packet

[0054] S01: Determine whether the connection port is abnormal

[0055] S02: Set the abnormal connection port to switch to closed state

[0056] S03: Send the abnormal information packet via the connection port that is not abnormal and is in the enabled state

[0057] S04: Determine whether an abnormal information packet is received

[0058] S05: Determine whether one of the connection ports is in a closed state

[0059] S06: Set the connection port that is in the closed state to switch to the enabled state

[0060] S07: Do not forward abnormal information packets

[0061] S08: Forward abnormal information packet

Claims

1. A network switch adapted to form a single ring network, the network switch comprising: A plurality of connection ports, when the network switch is in the path of the single ring network, each of the connection ports is preset to be in an enabled state or a disabled state, each of the plurality of connection ports is coupled to a connection port of another network switch via a transmission line to form the single ring network between the network switch and the other network switches, each of the connection ports in the enabled state receives a data packet in the single ring network and forwards the data packet, and each of the connection ports in the disabled state receives the data packet in the single ring network and does not forward the data packet; and A processing circuit is coupled to the connection ports, and is used to determine whether the connection ports forming the single ring network in the network switch are abnormal, and determine whether any of the connection ports forming the single ring network receives a first abnormal information packet from other network switches. When any of the connection ports receives the first abnormal information packet, and one of the connection ports forming the single ring network is in the closed state, the processing circuit sets the connection port in the closed state to switch to the enabled state, and the processing circuit does not forward the first abnormal information packet in the single ring network; as well as When one of the connection ports forming the single ring network in the network switch is abnormal and all the connection ports forming the single ring network in the network switch are in the enabled state, the processing circuit sets the abnormal connection port to switch to the closed state, and transmits a second abnormal information packet to other network switches in the single ring network via another normal connection port. The network switch and other network switches in the single ring network are not root bridges.

2. The network switch as described in claim 1, wherein when any of the connection ports receives the first exception information packet, if all of the connection ports of the network switch forming the single ring network are in the enabled state, the processing circuit forwards the first exception information packet to other network switches in the single ring network via another of the connection ports that has not received the second exception information packet. 3 . The network switch as claimed in claim 1 , wherein the connection port in the enabled state is directly switched to the disabled state without passing through other port states, and the connection port in the disabled state is directly switched to the enabled state without passing through other port states. 4 . The network switch as claimed in claim 3 , wherein the other port status is a listening state, a learning state, a useless state or any combination thereof.

5. The network switch as claimed in claim 1, wherein after the abnormal connection port is switched to the closed state, if one of the connection ports receives a third abnormal information packet from another network switch, the processing circuit sets the abnormal connection port to remain in the closed state instead of switching to the enabled state. 6 . The network switch of claim 1 , wherein the processing circuit does not send BPDU defined by a spanning tree protocol in the single ring network. 7 . The network switch of claim 1 , wherein the processing circuit does not send the MAC address of the network switch to other network switches when forming the single ring network.

8. The network switch as claimed in claim 1, wherein the first abnormal information packet and the second abnormal information packet do not include a MAC address and an identifier of the network switch.

9. A network switch system, adapted to form a single ring network, the network switch system comprising: The first network switch comprises: a plurality of first connection ports, which are preset to be in an enabled state when the first network switch is in the path of the single ring network, the plurality of first connection ports are each coupled to a connection port of another network switch via a transmission line to form the single ring network between the first network switch and the other network switches, and transmit data packets received from the other network switches in the single ring network; and A first processing circuit is coupled to the first connection ports, and when one of the first connection ports forming the single ring network in the first network switch is abnormal and all the first connection ports forming the single ring network are in the enabled state, the first processing circuit sets the abnormal first connection port to be switched to a closed state, and transmits an abnormal information packet in the single ring network via another first connection port that is not abnormal; and The second network switch is coupled to the first network switch and comprises: A second connection port, coupled to the first network switch, is in the closed state by default to form the single ring network and does not forward data packets received from the first network switch; and a second processing circuit coupled to the second connection port, and when the second connection port receives the abnormal information packet, the second processing circuit sets the second connection port to switch from the closed state to the enabled state to form another single ring network, and the second processing circuit does not forward the abnormal information packet, The first network switch, the second network switch and other network switches in the single ring network are not root bridges.

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