CN106487679B - Active-standby switching system and switching method of Ethernet switch - Google Patents

Abstract

The embodiment of the present invention relates to a master-standby switchover system and a switchover method of an Ethernet switch. The device includes: a first link optical signal detection unit, which detects an optical signal of the first link and outputs a first detection signal ; The first link interruption detection unit detects the link state of the first link and outputs a second detection signal; the second link optical signal detection unit detects the optical signal of the second link, and output a third detection signal; the second link interruption detection unit detects the link state of the second link, and outputs a fourth detection signal; a preprocessing unit, after the first detection signal and/or the second 2. When the state of the detection signal changes, an interrupt trigger signal is output; the processor generates a link switch control signal according to the interrupt trigger signal, so as to switch the Ethernet access port of the local switch from the first link connected to the first link. The port is switched to be connected to the second port of the second link.

Description

Active-standby switching system and switching method of Ethernet switch

technical field

The invention relates to the technical field of Ethernet communication, in particular to an active-standby switching system and a switching method of an Ethernet switch.

Background technique

With the rapid development of network technology, Ethernet network communication has been widely used. While pursuing high speed, network communication also has strict requirements on the reliability and stability of communication. Therefore, in some specific networks, it is required to use redundant backup network ports, that is, to connect to the network through two links, one of which is used for work and the other is used for backup. After the current working link is disconnected, it can automatically switch to the backup link for network communication.

In order not to affect the communication quality, the switching time is required, and the switching needs to be completed within the specified time range. From the perspective of current technology, switch devices generally adopt Ethernet Operation, Administration & Management (OAM) technology (in compliance with Y1731, 802.1ag protocol), and detect whether the current physical channel is unblocked through the CCM message message continuity detection mechanism, and the CCM message The minimum message interval is 3.3ms. If the receiver cannot receive the message message within the receiving time of three consecutive CCM messages, it will be concluded that the physical connection link is faulty, and a CCM message will be sent to notify the sender. Trigger port switching, through this mechanism, the reliability of the link can be ensured from the business level.

Using this technical solution, there are currently three options to implement it:

One is to use a special Gigabit network switching chip, and there will be an integrated dedicated central processing unit (CPU) inside the chip to control the OAM protocol. Using a special microcode can realize the active/standby switchover of the Gigabit Ethernet link Function. The disadvantage is that adopting this solution will increase the R&D cost of hardware.

The second is to use a special external CPU for OAM network protocol control, and run the OAM protocol exclusively on this CPU. This solution is basically the same as the above solution, but in comparison, the cost of hardware development will be lower. There is a slight reduction, but this solution will increase the corresponding software development costs.

The third is to use an external field programmable gate array (Field-Programmable Gate Array, FPGA) to carry out the corresponding OAM network protocol control. Similarly, this solution will also increase the cost of software and hardware development.

Therefore, no matter which existing solution is adopted, the use of Ethernet OAM to ensure the reliability of the link has its corresponding defects, including the requirement that the equipment on the network must support OAM; Perform corresponding network settings, such as setting related maintenance domains and maintenance sets.

Contents of the invention

The purpose of the present invention is to provide a master/standby switchover system and a switchover method of an Ethernet switch, which does not require complex link control protocols to ensure the reliability of the link, is simple and easy to implement, and can shorten product development costs and time, while Also does not require more hardware support, thereby saving hardware costs.

In order to achieve the above object, in a first aspect, the present invention provides a master/standby switching system of an Ethernet switch, comprising:

The first link optical signal detection unit detects the optical signal of the first link, and outputs a first detection signal; wherein, the first link is the main link in the current state;

The first link interruption detection unit detects the link status of the first link and outputs a second detection signal;

The second link optical signal detection unit detects the optical signal of the second link, and outputs a third detection signal; the second link is a standby link in the current state;

The second link interruption detection unit detects the link status of the second link and outputs a fourth detection signal;

A preprocessing unit, receiving the first detection signal, the second detection signal, the third detection signal and the fourth detection signal; in the current state, when the state of the first detection signal and/or the second detection signal changes , the preprocessing unit outputs an interrupt trigger signal;

a processor, receiving the interrupt trigger signal, and generating a link switching control signal according to the interrupt trigger signal;

The local switch receives the link switch control signal, and switches the Ethernet access port of the local switch from the first port connected to the first link to the first port connected to the second link according to the link switch control signal. Two ports.

Preferably, the processor generates a status query signal according to a preset time interval, and sends the status query signal to the local exchange;

The local switch obtains the link state state information of the first link and the link state state information of the second link according to the state query signal, and sends the link state information of the first link The status information of the status and the status information of the link status of the second link are sequentially sent to the processor according to the preset time interval;

The processor determines whether to perform link switching according to the state information of the link state of the first link and the state information of the link state of the second link; wherein, when the link state of the first link The processor generates a link switching control signal when the status information of the .

Further preferably, when the state information of the link state of the second link changes, the processor generates a fault signal to prompt that the standby link is abnormal.

Preferably, after generating the link switching control signal, the processor generates an address resolution protocol ARP message, and sends the ARP message to the upper-level switch through the second link connected to the second port of the local switch; wherein , the ARP packet includes media access control MAC address information of the second port.

Preferably, after generating the link switching control signal, the processor deletes the MAC address information of the first port in the MAC address table, and adds the MAC address information of the second port.

In a second aspect, the present invention provides a method for active/standby switching of an Ethernet switch, comprising:

Detect the optical signal of the first link, output a first detection signal, and detect the link state of the first link, and output a second detection signal; wherein, the first link is in the current state under the main link; and

Detect the optical signal of the second link, output a third detection signal, and detect the link state of the second link, and output a fourth detection signal; the second link is in the current state standby link;

In the current state, when the state of the first detection signal and/or the second detection signal changes, an interrupt trigger signal is generated, so that the processor generates a link switching control signal according to the interrupt trigger signal, so that the local exchange The Ethernet access port is switched from the first port connected to the first link to the second port connected to the second link.

Preferably, before port switching, the method further includes:

Generate a status query signal according to a preset time interval;

According to the state query signal, sequentially acquire the state information of the link state of the first link and the state information of the link state of the second link according to the preset time interval;

When the state information of the link state of the first link changes, the processor generates a link switching control signal. Further preferably, the method also includes:

When the state information of the link state of the second link changes, a fault signal is generated to prompt that the standby link is abnormal.

Preferably, after generating the link switching control signal, the method further includes:

Generate an address resolution protocol ARP message, and send the ARP message to the upper-level switch through the second link connected to the second port of the local switch; wherein, the ARP message includes the media access control of the second port MAC address information.

Preferably, after generating the link switching control signal, the method further includes:

Delete the MAC address information of the first port in the MAC address table, and add the MAC address information of the second port.

The active-standby switchover system of the Ethernet switch provided by the embodiment of the present invention does not require complex link control protocols to ensure the reliability of the link, is simple and easy to implement, can shorten product development costs and time, and does not require more Hardware support, thus saving hardware costs.

Description of drawings

FIG. 1 is a schematic diagram of an application scenario of an active-standby switching system of an Ethernet switch provided by an embodiment of the present invention;

Fig. 2 is the structural block diagram of the active-standby switching system of Ethernet switch that the embodiment of the present invention provides;

FIG. 3 is a flow chart of a master/standby switchover method for an Ethernet switch provided by an embodiment of the present invention.

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

The active-standby switching system of the Ethernet switch provided by the embodiment of the present invention can be applied to a dedicated network or a small control network. Specifically, it can be shown in FIG. 1 .

Devices 1 to 11 are connected to downlink ports of the active/standby switching system, and are connected to the network through the active/standby switching system 1 . The active/standby switching system 1 includes a control module 101 and a local switch 102 . The uplink ports P12 and P16 in the local switch 102 are active and standby redundant ports for connecting to the switch 2 and the switch 3 respectively. Switch 2 and Switch 3 are connected to Router 1 and Router 2 respectively. These two routers can be used as gateway devices. For the sake of simplicity, the two routers are also redundant backups, so they use the same network MAC and IP.

The active-standby switching system 1 selects the P12 port or the P16 port to be connected to the network through the control module 101, as the main link port for connecting the device 1 to the device 11 to the network, so as to realize the network through the link of the switch 2 and the router 1. Connect or realize the network connection through the link of the switch 3 and the router 2.

Next, taking FIG. 2 as an example, the active-standby switching system of the Ethernet switch of the present invention will be described.

As shown in the figure, the active-standby switching system of the Ethernet switch in the embodiment of the present invention includes: a first link optical signal detection unit 11, a second link optical signal detection unit 12, a first link interruption detection unit 21, a second link optical signal detection unit Two link interruption detection unit 22 , preprocessing unit 3 , processor 4 and local switch 5 .

The first link optical signal detection unit 11 detects the optical signal of the first link, and outputs a first detection signal P12_SD;

The first link interruption detection unit 21 can be implemented specifically by a PHY chip, detects the link state of the first link, and outputs the second detection signal PHY_INT1;

The second link optical signal detection unit 12 detects the optical signal of the second link, and outputs a third detection signal P16_SD;

The second link interruption detection unit 22, which can be implemented specifically by a PHY chip, detects the link state of the second link, and outputs a fourth detection signal PHY_INT2;

The preprocessing unit 3 receives the first detection signal P12_SD, the second detection signal PHY_INT1, the third detection signal P16_SD and the fourth detection signal PHY_INT2;

Assuming that in the current state, the first link is the main link and the second link is the standby link, the preprocessing unit 3 detects the signal states of the first detection signal P12_SD and the third detection signal PHY_INT1, when the first detection When the state of the signal P12_SD and/or the third detection signal PHY_INT1 changes, the preprocessing unit 3 outputs an interrupt trigger signal;

Assuming that in the current state, the second link is the main link and the first link is the backup link, the preprocessing unit 3 detects the signal states of the third detection signal P16_SD and the fourth detection signal PHY_INT2, when the second detection When the state of the signal P16_SD and/or the fourth detection signal PHY_INT2 changes, the preprocessing unit 3 outputs a valid interrupt trigger signal;

Among them, the first link optical signal detection unit 11 and the second link optical signal detection unit 12 can be implemented by using a signal detection SFP optical module, and the first link interruption detection unit 21 and the second link interruption detection unit 22 can be implemented by using It is realized by detecting the Ethernet PHY chip, and the preprocessing unit 3 can be realized by using a complex programmable logic device CPLD.

The processor 4 receives the interrupt trigger signal INT1, and generates a link switching control signal ctl1 when detecting that the interrupt trigger signal INT1 is valid;

The local exchange 5 receives the link switching control signal ctl1, and switches the Ethernet access port of the local exchange from the first port P12 connected to the first link to the second port connected to the second link according to the link switching control signal ctl1 P16.

In order to realize active-standby switching, after the processor 4 generates the link switching control signal ctl1, an address resolution protocol (ARP) message will be generated, and the ARP message will be connected to the second port P16 of the local switch 5. The link is sent to the upper-level switch; wherein, the ARP message includes information such as the media access control (MAC) address of the second port P16. Thus, in conjunction with what is shown in FIG. 1, in the network shown in FIG. 1, the information of the MAC address of the second port P16 is sent to the upper-level switch, that is, the switch 2 and the switch 3 in FIG. 1, through the ARP message, so that Switch 2 and switch 3 can quickly learn the MAC address of the new port, thereby shortening the MAC address learning time.

In addition, the processor 4 also deletes the MAC address information of the first port P12 from the stored MAC address table, and adds the MAC address information of the second port P16 to the MAC address table.

As mentioned above, the master-standby switchover system of the Ethernet switch of the present invention has a link optical signal inspection guarantee mechanism and a PHY chip physical link up/down detection guarantee mechanism.

The link optical signal inspection guarantee mechanism determines whether there is an optical signal by detecting the level change of the signal generated by the SFP optical module of the current access port (active port), for example, when the SFP optical module receives an optical signal, it outputs a high level detection signal, and output a low-level detection signal when no optical signal is received. Therefore, when there is no optical signal, the low-level detection signal received by the CPLD can be used to determine that the link is interrupted, thereby reporting to the processor 4 . The advantage of the link optical signal inspection guarantee mechanism is that this method has the highest efficiency and can detect the abnormal disconnection of the active port fiber fastest. The disadvantage is that this method cannot be used when the remote optical module is working abnormally but the optical path is still connected. A method to detect link outages.

The PHY chip physical link up/down detection guarantee mechanism is to detect the transmission code stream of the link through the PHY chip. When the code stream transmission is interrupted, the detection signal of the PHY chip undergoes level conversion, such as from high level to It is a low level, thus avoiding the disadvantage that the code stream interruption cannot be reported when the optical signal is constant from the physical layer.

Therefore, through the link optical signal inspection guarantee mechanism and the PHY chip physical link up/down detection guarantee mechanism, the physical link down (including optical signal loss and code stream loss) can be effectively detected, and the processor can report the 4. Realize the switching of controlling the active and standby ports, so as to realize the switching of network communication from the working link to the backup link.

The above two guarantee mechanisms are passive guarantee mechanisms that switchover will be performed only when an exception is received through the active-standby switchover system when an abnormality occurs in the link. In addition, the active-standby switching system of the Ethernet switch provided by the embodiment of the present invention also provides a polling detection guarantee mechanism for actively querying the link state, which provides double guarantees for the detection effectiveness of the active-standby switching system.

As shown in FIG. 2 , in the active-standby switching system of the Ethernet switch in this embodiment, the processor 4 generates a status query signal according to preset time detection, and sends the status query signal to the local switch 5 .

Specifically, the processor 4 generates a status query signal according to a preset time interval, and sends the status query signal to the physical layer device under the local switch for link query. As shown in the figure, the specific query signal path is that after the processor 4 sends the query signal to the control port of the local exchange 5 through the control port, the local exchange 5 communicates with the physical layer device (the PHY chip 21 and the PHY chip 22 in the figure) through the SMI_PHY interface. ) to query the corresponding status register, and feed back the queried information through the same path.

The processor 4 sequentially acquires the link status information of the first link detected by the first link interruption detection unit 21 and the link status information of the second link detected by the second link interruption detection unit 22 at preset time intervals. State information of road state;

When the first link is the working link and the second link is the standby link:

When polling detects that the link state of the first link changes, it indicates that the working link is abnormal, and at this time, the processor 4 generates a link switching control signal ctl1 to control switching of the access port of the local exchange 5 by connecting the first The first port P12 of the link is switched to be connected to the second port P16 of the second link.

In addition, the status of the standby link is also monitored through polling detection. When the polling detects that the link state of the second link changes, it means that the standby link has failed, and at this time, the processor 4 will generate a fault signal to prompt the relevant staff that the standby link is abnormal, so that the staff can Check and repair the standby link in time, so that the normal communication transmission will not be affected when the active and standby links need to be switched.

The polling cycle can be set according to the performance of the processor 4, preferably a polling cycle of 5 ms to 10 ms can be used.

Usually, the link optical signal inspection guarantee mechanism and the physical link up/down detection guarantee mechanism of the PHY chip are triggered earlier than the polling detection guarantee mechanism. That is, when an abnormality occurs, it will first be detected by the link optical signal inspection guarantee mechanism and the physical link up/down detection guarantee mechanism of the PHY chip. However, adding the polling detection protection mechanism can provide double protection for the active/standby switching system of the present invention.

The active-standby switchover system of the Ethernet switch provided by the embodiment of the present invention does not require complex link control protocols to ensure the reliability of the link, is simple and easy to implement, and does not require more hardware support, which greatly saves cost.

Correspondingly, the embodiment of the present invention also provides a master-standby switchover method of an Ethernet switch, which is implemented in the master-standby switchover system of the above-mentioned embodiment.

As shown in Figure 3, the method includes the following steps:

Step 310, initialization of the active/standby switching system;

Specifically, after the system is powered on and started, the main interface is firstly configured through the configuration command line in the processor. As shown in Figure 2, if the two ports P12 and P16 have optical fibers inserted, that is, when both ports are in the link up state, it will determine which port is the active port according to the configuration, and at the same time set the standby port according to the configuration information. The link of the Ethernet interface is down, and the configuration data sent by the interface is saved in the query configuration module through the configuration command line. In this example, first set the first link connected to the P12 port as the working link, that is, the P12 port is the active port.

Subsequently, the hook initialization of the interrupt processing function is carried out, which is mainly used to generate interrupts for optical signal detection and PHYLink UP/DOWN interrupts. Then start regular polling of the active and standby link status, and set the polling interval.

Step 320: Detect the optical signal of the first link, output a first detection signal, and detect the link status of the first link, and output a second detection signal; performing detection, outputting a third detection signal, and detecting the link state of the second link, and outputting a fourth detection signal;

Specifically, the detection of the optical signal is to determine whether there is an optical signal by detecting the level change of the signal generated by the SFP optical module connected to the current access port, for example, when the SFP optical module receives the optical signal, it outputs a high level The detection signal outputs a low-level detection signal when no optical signal is received. Therefore, if the optical path transmission is abnormal, the signal output of the SFP optical module will change from high level to low level.

When detecting the link state, the transmission code stream of the link is detected by the PHY chip. When the transmission of the code stream is interrupted, the detection signal of the PHY chip undergoes level conversion, such as changing from high level to low level.

Step 330: Generate a status query signal according to a preset time interval, and according to the status query signal, sequentially acquire the status information of the link status of the first link and the status information of the second link according to the preset time interval. Status information for link status.

Specifically, when the polling detects that the link state of the first link changes, it indicates that the working link is abnormal.

The above step 320 and step 330 may be executed synchronously.

Step 340, when the state of the first detection signal and/or the second detection signal changes, or when it is detected that the state information of the link state of the first link changes, generate a link switching control signal, thereby switching the local switch to The Ethernet access port is switched from the first port connected to the first link to the second port connected to the second link.

Specifically, when either or both of the first detection signal or the second detection signal changes, such as changing from a high level to a low level, it indicates that the optical signal or code stream transmission of the current working link is abnormal; When polling detects that the link state of the first link changes, it also indicates that the working link is abnormal; when any of the above situations occurs, the processor will generate a link switching control signal to control the access of switching the active and standby links .

Step 350, generate an address resolution protocol ARP message, and send the ARP message to the upper-level switch through the second link connected to the second port of the local switch.

Specifically, the ARP packet includes media access control MAC address information of the second port. As a result, the upper-level switch can quickly learn the MAC address of the new port, thereby shortening the time for learning the MAC address.

In addition, it is also necessary to delete the MAC address information of the first port and add the MAC address information of the second port in the MAC address table.

In order to ensure that the communication quality is not affected, the switching process of the active and standby links needs to be completed within the specified time range.

The following uses a specific example to describe the switching time.

Assuming that the number of MAC addresses of the devices connected to the local switch in the system does not exceed 20, based on the calculation of transmitting a MAC address to the upper-level switch every 1ms, it takes 20ms to notify the upper-level switch of the MAC address table of the active port for active/standby switching. Port physical switching time does not exceed 10ms.

When the MAC address table is dynamically configured, the MAC address table of the aging port can be deleted through a command. The advantage of dynamic configuration is that the MAC address is automatically learned by the switch. The disadvantage is that if a host or motherboard is a special device that only receives messages, the switch cannot obtain its MAC address and cannot communicate with the device.

For static configuration, MAC address entries need to be deleted one by one. Static configuration means that after the switch is initialized, manually add the MAC addresses of each motherboard and host in the system to the MAC address table through commands, so that the communication problem between the special motherboard and the switch can be solved. The disadvantage is that the motherboard and the host The MAC address of the host must be fixed. Dynamic addition or change of the MAC address of each host board in the system is not supported, and the port switching aging address entries need to be deleted one by one, which takes a long time. The P12 and P16 ports of the switch must record the MAC address table of the gateway and must be statically configured. Generally, there are one or two gateway address tables. Therefore, a total of 2 address entries need to be deleted and added.

According to the static configuration, it takes about 12ms to delete and add two address entries, plus other time consumptions analyzed above, the total switching time is 42ms. The above is only an example analysis of a practical example, and is not used to limit the switching time of the master-standby switchover method of the Ethernet switch in the present invention in practical applications.

The active-standby switchover method of the Ethernet switch provided by the embodiment of the present invention does not require complex link control protocols to ensure the reliability of the link, is simple and easy to implement, can shorten product development costs and time, and does not require more Hardware support, thus saving hardware costs.

Professionals should further realize that the units and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the relationship between hardware and software Interchangeability. In the above description, the composition and steps of each example have been generally described according to their functions. Whether these functions are executed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be regarded as exceeding the scope of the present invention.

The steps of the methods or algorithms described in connection with the embodiments disclosed herein may be implemented by hardware, software modules executed by a processor, or a combination of both. Software modules can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other Any other known storage medium.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (8)

1. an active-standby switching system of an Ethernet switch, characterized in that, the active-standby switching system comprises: The first link optical signal detection unit detects the optical signal of the first link, and outputs a first detection signal; wherein, the first link is the main link in the current state; The first link interruption detection unit detects the link status of the first link and outputs a second detection signal; The second link optical signal detection unit detects the optical signal of the second link, and outputs a third detection signal; the second link is a standby link in the current state; The second link interruption detection unit detects the link status of the second link and outputs a fourth detection signal; A preprocessing unit, receiving the first detection signal, the second detection signal, the third detection signal and the fourth detection signal; in the current state, when the state of the first detection signal and/or the second detection signal changes , the preprocessing unit outputs an interrupt trigger signal; a processor, receiving the interrupt trigger signal, and generating a link switching control signal according to the interrupt trigger signal; the processor generates a status query signal according to a preset time interval, and sends the status query signal to the local switch; the local switch obtains the state information of the link state of the first link and the state information of the link state of the second link according to the state query signal, and transfers the state information of the link state of the first link The state information of the link state and the state information of the link state of the second link are sequentially sent to the processor according to the preset time interval; information and the state information of the link state of the second link to determine whether to perform link switching; wherein, when the state information of the link state of the first link changes, the processor generates a link switching control signal ; The local switch receives the link switch control signal, and switches the Ethernet access port of the local switch from the first port connected to the first link to the first port connected to the second link according to the link switch control signal. Two ports. 2. The active-standby switching system of the Ethernet switch according to claim 1, wherein when the state information of the link state of the second link changes, the processor generates a fault signal for It indicates that the standby link is abnormal. 3. the active/standby switching system of Ethernet exchange according to claim 1, is characterized in that, after generating link switching control signal, described processor generates Address Resolution Protocol ARP message, and described ARP message The second link connected through the second port of the local switch is sent to the upper-level switch; wherein, the ARP message includes the media access control MAC address information of the second port. 4. the active/standby switching system of Ethernet exchange according to claim 1, is characterized in that, after generating link switching control signal, described processor deletes the MAC address information of described first port in MAC address table , and add the MAC address information of the second port. 5. a method for active-standby switching of an Ethernet switch, characterized in that the method comprises: Detect the optical signal of the first link, output a first detection signal, and detect the link state of the first link, and output a second detection signal; wherein, the first link is in the current state under the main link; and Detect the optical signal of the second link, output a third detection signal, and detect the link state of the second link, and output a fourth detection signal; the second link is in the current state standby link; In the current state, when the state of the first detection signal and/or the second detection signal changes, an interrupt trigger signal is generated, so that the processor generates a link switching control signal according to the interrupt trigger signal, so that the local exchange The Ethernet access port is switched from the first port connected to the first link to the second port connected to the second link; Before port switching, the method also includes: Generate a status query signal according to a preset time interval; According to the state query signal, sequentially acquire the state information of the link state of the first link and the state information of the link state of the second link according to the preset time interval; When the state information of the link state of the first link changes, the processor generates a link switching control signal. 6. The method according to claim 5, further comprising: When the state information of the link state of the second link changes, a fault signal is generated to prompt that the standby link is abnormal. 7. The method according to claim 5, characterized in that, after generating the link switching control signal, the method further comprises: Generate an address resolution protocol ARP message, and send the ARP message to the upper-level switch through the second link connected to the second port of the local switch; wherein, the ARP message includes the media access control of the second port MAC address information. 8. The method according to claim 5, characterized in that, after generating the link switching control signal, the method further comprises: Deleting the MAC address information of the first port in the MAC address table, and adding the MAC address information of the second port.