WO2022089212A1 - Fault handling method and device - Google Patents

Abstract

The present application discloses a fault handling method and device, relating to the field of communications. The method helps reduce unknown unicast flooding, and helps reduce unknown unicast flooding in an ethernet virtual private network (EVPN) when used in scenarios such as EVPN, thereby reducing waste of communication resources. A first network device and a second network device are in communication connection. The method comprises: first, the second network device determines that a route to a media access control (MAC) address is unreachable, the MAC address being a MAC address of a user-side network device or a user host which is connected to the first network device; and second, in response to the determination, the second network device sets instruction information corresponding to the route to the MAC address, the instruction information being used for instructing the second network device, when receiving a message destined for the MAC address, not to forward the message.

Description

Troubleshooting method and device

This application claims the priority of the Chinese patent application with the application number 202011159217.9 and the application name "Fault Handling Method and Device", which was filed with the State Intellectual Property Office on October 26, 2020, the entire contents of which are incorporated into this application by reference.

technical field

The present application relates to the field of communications, and in particular, to a fault handling method and device.

Background technique

Ethernet private virtual network (ethernet virtual private network, EVPN) is a private virtual network (virtual private network, VPN) technology used for Layer 2 network interconnection. As shown in FIG. 1 , it is a schematic diagram of the architecture of an EVPN. EVPN includes multiple provider edge (PE) devices. PE devices within the EVPN are connected to each other. Customer edge (customer edge, CE) devices are connected to PE devices through switches. In Figure 1, the EVPN includes PE devices 1-3, and CE devices 1A and 1B are connected to PE device 1 through switch 1, CE device 2 is connected to PE device 2 through switch 2, and CE device 3 is connected to PE device 3 through switch 3 connect. Each CE device can be connected to one or more user hosts.

In the future fifth generation (5th Generation, 5G) bearer network, EVPN can be used as an important service implementation solution. The Ethernet local area network (E_LAN) under the EVPN network architecture is also widely used in the 5G bearer network. In E_LAN, when a switch fails, the PE device connected to the switch deletes the reachable media access control (MAC) route of the CE device connected to the switch in the local routing table, such as the MAC route to the CE device. and/or the MAC route to the user-side host connected to the CE device, which is referred to as the MAC route of the CE device for short here. After that, the PE device sends a border gateway protocol (BGP) update (update) message to other PE devices, so that the other PE devices delete the MAC route of the CE device in the local routing table. However, the switch connected to the other PE device cannot sense that the switch is faulty in time. Therefore, the switch connected to the other PE device may send a message addressed to the MAC address to the other PE device. After receiving the packet, the other PE device cannot find the MAC route in the local routing table, and triggers unknown unicast flooding in the EVPN, thus causing waste of communication resources.

For example, based on FIG. 1 , assuming that switch 1 fails, PE device 1 deletes the MAC route of CE device 1A and the MAC route of CE device 1B; and sends BGP update messages to PE device 2 and PE device 3 respectively, so that PE device 2 and PE device 3 delete the MAC route of CE device 1A and the MAC route of CE device 1B. However, by adopting the above deletion method, switch 2 and switch 3 cannot sense that switch 1 is faulty in time, and therefore may also send packets destined for CE device 1A. If PE device 2 receives the packet sent by switch 2 and destined for CE device 1A, it cannot find the MAC route of CE device 1A in the local routing table, which triggers unknown unicast flooding in the EVPN.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a fault handling method and device, which help to reduce unknown unicast flooding, can be applied to various possible network scenarios such as EVPN, and help reduce unknown unicast traffic in the network. Flooding, thereby reducing the waste of communication resources.

In order to achieve the above purpose, the application provides the following technical solutions:

In a first aspect, the present application provides a fault handling method, wherein a first network device and a second network device are connected in communication. The method includes: the second network device determines that the route to the MAC address is unreachable, where the MAC address is the MAC address of the user-side network device or the user host connected to the first network device. In response to the determination, the second network device sets indication information corresponding to the routing of the MAC address. The indication information is used to instruct the second network device not to forward the packet when it receives the packet addressed to the MAC address. Since the second network device does not forward the message addressed to the MAC address, it is helpful to reduce the flooding of unknown unicast traffic in the network, thereby reducing the waste of communication resources.

In a possible design, after the second network device sets the indication information corresponding to the route of the MAC address, the method further includes: the second network device deletes the route of the MAC address. In this way, the storage space of the second network device can be released, thereby improving the utilization rate of the storage space.

In a possible design, deleting the route of the MAC address by the second network device includes: the second network device determines that the route to the MAC address is unreachable for a preset time, or determines to set the indication information to meet the preset time In this case, delete the route for the MAC address. That is, the second network device delays deleting the route of the MAC address. In this way, the risk of triggering unknown unicast flooding can be further reduced, thereby further reducing the waste of communication resources.

In a possible design, the second network device determines that the route to the MAC address is unreachable, including: when the third network device fails, or the link between the first network device and the third network device fails, the second network device fails. The network device receives the first message from the first network device, and determines that the route of the MAC address is unreachable according to the first message. The third network device is a user-side network device connected to the first network device. This possible design provides a specific implementation manner for determining that the MAC route is unreachable when the user-side network device is faulty or the link is faulty.

In a possible design, in addition to the first network device, one or more other network devices are also connected to the user-side network device or user host having the MAC address. In this case, the second network device receives the first message from the first network device, and determines that the route of the MAC address is unreachable according to the first message, which may include: the second network device receives the first message from the first network device, and One or more second messages are received from one or more other network devices. Then, the second network device determines that the route of the MAC address is unreachable according to the first message and the one or more second messages. This possible design can be applied to multi-homing scenarios of user-side devices.

In a possible design, the second network device determining that the route to the MAC address is unreachable includes: the second network device determines that the route to the MAC address is unreachable according to determining that the state of the first network device is faulty. This possible design provides a specific implementation manner for determining that the MAC route is unreachable when the network device, especially the device on the network side, fails.

In a possible design, in addition to the first network device, one or more other network devices are also connected to the user-side network device or user host having the MAC address. In this case, the second network device determines that the route of the MAC address is unreachable according to determining that the state of the first network device is faulty. If the status is all faulty, it is determined that the route to the MAC address is unreachable. This possible design can be applied to multi-homing scenarios of user-side devices.

In a possible design, the method further includes: the second network device determines that the state of the first network device is faulty according to the detection message sent to the first network device.

In one possible design, the third network device includes a switch.

In a possible design, the first message is a BGP Update message.

In a possible design, the indication information includes that the next hop of the route of the MAC address is NULL0.

In one possible design, the first network device and the second network device are EVPN neighbors.

In one possible design, the first network device and the second network device are PE devices.

In a second aspect, the present application provides a fault handling device. The fault handling device may be a chip or a network device.

In a possible design, the fault handling device is used to execute any one of the methods provided in the first aspect. According to the method provided in the above-mentioned first aspect, the present application can divide the functional modules of the fault processing device. For example, each function module may be divided corresponding to each function, or two or more functions may be integrated into one processing module. Exemplarily, the present application may divide the fault processing device into a determination unit, a setting unit, a deletion unit, and the like according to functions. For descriptions of possible technical solutions and beneficial effects performed by each of the above-divided functional modules, reference may be made to the corresponding technical solutions in the first aspect, which will not be repeated here.

In another possible design, the fault processing apparatus includes: a processor, configured to implement any one of the methods described in the first aspect above. The apparatus may further include a memory, and the memory is coupled to the processor. When the processor executes the instructions stored in the memory, any one of the methods described in the first aspect can be implemented. The device may also include a communication interface for the device to communicate with other devices, for example, a communication port may be a transceiver, circuit, bus, module, or other type of communication interface. In this application, the instructions in the memory can be stored in advance or downloaded from the Internet and stored when the device is used, and this application does not uniquely limit the source of the instructions in the memory. The coupling in this embodiment of the present application is an indirect coupling or connection between units or modules, which may be in electrical, mechanical or other forms, and is used for information interaction between units or modules.

In a third aspect, the present application provides a computer readable storage medium, such as a computer non-transitory readable storage medium. A computer program (or instruction) is stored thereon, and when the computer program (or instruction) runs on the fault processing apparatus, the fault processing apparatus is made to execute any one of the methods provided in the first aspect above.

In a fourth aspect, the present application provides a computer program product that, when run on a computer, enables any one of the methods provided in the first aspect to be performed.

In a fifth aspect, the present application provides a chip system, including: a processor, where the processor is configured to call and run a computer program stored in the memory from a memory, and execute any one of the methods provided in the first aspect.

In a sixth aspect, the present application provides a fault handling system, including: a first network device and a second network device. The first network device and the second network device are connected in communication. The second network device is configured to execute any one of the methods provided by the first aspect. The system may further include a third network device, where the third network device is a user-side network device connected to the first network device, for example, a switch or a CE device.

It can be understood that any fault processing device, computer storage medium, computer program product or conference system provided above can be applied to the corresponding methods provided above, therefore, the beneficial effects that can be achieved can be referred to. The beneficial effects in the corresponding method will not be repeated here.

In this application, the names of the above-mentioned fault handling apparatuses do not limit the devices or functional modules themselves, and in actual implementation, these devices or functional modules may appear in other names. As long as the functions of each device or functional module are similar to those of the present application, they fall within the scope of the claims of the present application and their equivalents.

These and other aspects of the present application will be more clearly understood from the following description.

Description of drawings

1 is a schematic structural diagram of an EVPN applicable to an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a fault handling system according to an embodiment of the present application;

3 is a schematic structural diagram of another fault handling system provided by an embodiment of the present application;

FIG. 4 is a schematic structural diagram of a communication device according to an embodiment of the present application;

FIG. 5 is a schematic flowchart of a fault handling method provided by an embodiment of the present application;

FIG. 6 is a schematic structural diagram of a second network device according to an embodiment of the present application.

Detailed ways

The terms "first", "second" and "third" in the description and claims of the present application and the above drawings are used to distinguish different objects, rather than to limit a specific order.

In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or illustrations. Any embodiments or designs described in the embodiments of the present application as "exemplary" or "such as" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present the related concepts in a specific manner to facilitate understanding.

In the description of this application, unless otherwise stated, "/" indicates that the object associated with it is an "or" relationship, for example, A/B can indicate A or B; "and/or" in this application is only It is an association relationship that describes an associated object, which means that there can be three kinds of relationships, for example, A and/or B, which can be expressed as: A alone exists, A and B exist at the same time, and B exists alone, among which A, B Can be singular or plural. Also, in the description of the present application, unless stated otherwise, "plurality" means two or more than two. "At least one item(s) below" or similar expressions thereof refer to any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (a) of a, b, or c can represent: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, c may be single or multiple .

In the embodiments of the present application, at least one may also be described as one or more, and the multiple may be two, three, four or more, which is not limited in this application.

As mentioned above, in EVPN, when a switch fails, the PE device connected to the switch is deleted and other PE devices delete the MAC route of the CE device connected to the switch in the local routing table. This will cause the other PE device to trigger an unknown unicast in the EVPN because it cannot find the MAC route of the CE device in the local routing table after receiving the message "The destination MAC address is the MAC address of the CE device". Flood in the middle, resulting in a waste of communication resources.

In view of this, an embodiment of the present application provides a fault handling method. Specifically, when the second network device determines that the route to the MAC address is unreachable, it sets indication information corresponding to the MAC address, where the indication information is used to indicate When the second network device receives the packet addressed to the MAC address, the packet is not forwarded. The MAC address is the MAC address of the user-side network device or the user host connected to the first network device. In this way, even if the second network device cannot find the route of the MAC address in the local routing table when it receives the packet destined for the MAC address, it will not trigger unknown unicast in some application scenarios, such as the EVPN scenario. Compared with the traditional technology, the flooding in the system helps to reduce the waste of communication resources.

As an example of a possible scenario, the technical solutions provided in the embodiments of the present application may be applied to E_LAN, or may also be referred to as: EVPN virtual private LAN service (VPLS) in some scenarios. Understandably, the embodiments of the present application may also be applied to other network scenarios that may cause similar technical problems.

The solutions provided by the embodiments of the present application can be applied to the fault handling system 20 shown in FIG. 2 . As shown in FIG. 2, the message transmission system 20 may include multiple network side network devices (eg, network side network devices 201-204), multiple user side network devices (eg, user side network devices 205-207), and multiple user hosts (eg, user hosts 208-211).

The network devices on the network side can communicate through the border gateway protocol (BGP). The network devices on the network side may communicate through tunnels or communicate in other ways. A network-side network device can be connected to one or more user-side network devices, for example, network-side network device 201 is connected to user-side network device 205, and network-side network device 204 is connected to user-side network devices 206-207. The network device on the network side may be a PE device. For example, when the network device on the network side is a PE device, each PE device in the fault handling system 20 may be configured with the same EVPN instance. Each network-side network device includes one or more outgoing interfaces, and each outgoing interface can be connected to a network-side network device or a user-side network device. For example, the network-side network device 204 includes outgoing interfaces 1-5, which are respectively used to connect the user-side network devices 206-207 and the network-side network devices 201-203.

The user-side network device communicates with another user-side network device through one or more network-side network devices. For example, the user-side network device 205 communicates with the user-side network device 206 through the network-side network device 201 and the network-side network device 204 . A user-side network device can be connected to one or more network-side network devices. For example, the user-side network device 206 is connected to the network-side network device 204, that is, a single-homing scenario; the user-side network device 205 is connected to the network-side network device 201- 203 connection, that is, a multi-homing scenario. One user side network device may be connected to one or more user hosts, for example, the user side network device 205 is connected to the user host 208, and the user side network device 206 is connected to the user hosts 209-210. The user-side network device may be a CE device or a switch. The switch may, for example, assume the role of an access server.

The user host communicates with another user host through one or more user side network devices and one or more network side network devices. For example, the user host 208 communicates with the user host 209 through the user side network device 205 , the network side network devices 201 and 204 , and the user side network device 206 .

Each network-side network device can maintain (or manage) a routing table locally, that is, a local routing table. The local routing table can contain one or more routes, namely MAC routes. Each route includes a destination MAC address and the identifier of the next hop node corresponding to the destination MAC address. The identifier of the next-hop node is used to indicate the next-hop node of the packet whose destination address is the destination MAC address.

The destination MAC address included in the route in the local routing table maintained by the network device on the network side includes at least the following:

Case 1: The destination MAC address is the MAC address of the user-side network device to which the network-side network device is connected.

Case 2: The destination MAC address is the MAC address of the user host connected to the network device on the network side. For example, the MAC address of the user host connected to the network device on the network side through the user side network device.

Case 3: The destination MAC address is the MAC address of the user-side network device connected to other network-side network devices.

Case 4: The destination MAC address is the MAC address of the user host connected to other network-side network devices.

For example, based on FIG. 2 , the routing table maintained by the network device 204 on the network side can illustratively include the following routing table entry information:

Table 1

It should be noted that, in an example, each network-side network device may learn the local MAC address, that is, the MAC address of the user-side network device connected to the network-side network device and the MAC address of the user host connected to the network-side network device. MAC address, and create a routing table entry (called a local routing table entry) based on the learned MAC address. Then, the network-side network device may send local routing table entries to other network-side network devices, and receive local routing table entries established by the other network-side network devices sent by the other network-side network devices. Each network-side network device generates a routing table based on the local routing table entries established by itself and the local routing table entries established by the other network-side network devices. For the specific implementation manner, reference may be made to the prior art, which will not be repeated here.

For example, when the network device on the network side is a PE device, the PE devices can exchange their local routing table entry. Subsequently, when a network device on the network side receives the packet, it queries the routing table according to the destination address of the packet to determine the next hop node of the packet and forward the packet to the next hop node.

Optionally, the fault handling system 20 may include multi-level user side network devices. For example, as shown in FIG. 3 , it is an example of a fault handling system 20 including multi-level user side network devices. Specifically, the user host 211 in FIG. 3 accesses the network side network device 204 through the user side network device 212 and the user side network device 207 (ie, two levels of user side network devices). One user-side network device may be connected to one or more user-side network devices. FIG. 3 is drawn based on FIG. 2 . Therefore, for the explanation of other devices in FIG. 3 , reference may be made to the description for FIG. 2 , which will not be repeated here.

Further optionally, the user-side network device directly connected to the user host may be a CE device, and the user-side network device indirectly connected to the user host may be a switch. For example, the user-side network device 212 in FIG. 3 may be a CE device, and the user-side network device 207 may be a switch.

The fault handling system 20 can be used for EVPN. When applied to EVPN, the network device on the network side may specifically be a PE device, and the network device on the user side may specifically be a CE device or a switch. In EVPN, any two PE devices can be connected through an operator's backbone (provider, P) device, and the P device acts as a forwarding device between the two PE devices to forward data packets between the PE devices. The EVPN here may be a single-homing scenario or a multi-homing scenario (eg, a dual-homing scenario). The single-homing scenario refers to a user-side network device (such as a CE device or a switch) accessing the EVPN through a PE device. In the multi-homing scenario, a user-side network device accesses the EVPN through multiple PE devices. The dual-homing scenario refers to a user-side network device accessing the EVPN through two PE devices.

By way of example, with reference to FIG. 1 , the PE device in FIG. 1 may be a specific implementation of the network-side network device in FIG. 2 , and the CE device and switch in FIG. 1 may be a specific implementation of the user-side network device in FIG. 2 . The user host in 1 may be a specific implementation of the user host in FIG. 2 .

In terms of hardware implementation, both the network-side network device and the user-side network device described above may be implemented by a communication device as shown in FIG. 4 . As shown in FIG. 4 , it is a schematic diagram of a hardware structure of a communication device 40 according to an embodiment of the present application. The communication device 40 may be used to implement the functions of the network device on the network side or the network device on the user side.

The communication device 40 shown in FIG. 4 may include: a processor 401 , a memory 402 , a communication interface 403 and a bus 404 . The processor 401 , the memory 402 and the communication interface 403 may be connected through a bus 404 .

The processor 401 is the control center for generating the communication device 40, which may be a general-purpose central processing unit (central processing unit, CPU), or other general-purpose processors. Wherein, the general-purpose processor may be a microprocessor or any conventional processor or the like.

As an example, processor 401 may include one or more CPUs, such as CPU 0 and CPU 1 shown in FIG. 4 .

The memory 402 may be read-only memory (ROM) or other type of static storage device that can store static information and instructions, random access memory (RAM) or other type of static storage device that can store information and instructions A dynamic storage device that can also be an electrically erasable programmable read-only memory (EEPROM), a magnetic disk storage medium, or other magnetic storage device, or can be used to carry or store instructions or data structures in the form of desired program code and any other medium that can be accessed by a computer, but is not limited thereto.

In one possible implementation, the memory 402 may exist independently of the processor 401 . The memory 402 may be connected to the processor 401 through a bus 404 for storing data, instructions or program codes. When the processor 401 calls and executes the instructions or program codes stored in the memory 402, the fault handling method provided by the embodiment of the present application can be implemented.

In another possible implementation manner, the memory 402 may also be integrated with the processor 401 .

The communication interface 403 is used to connect the communication device 40 with other devices through a communication network, and the communication network can be an Ethernet, a radio access network (RAN), a wireless local area network (wireless local area networks, WLAN) and the like. The communication interface 403 may include a receiving unit for receiving data, and a transmitting unit for transmitting data.

The bus 404 may be an industry standard architecture (industry standard architecture, ISA) bus, a peripheral component interconnect (peripheral component interconnect, PCI) bus, or an extended industry standard architecture (extended industry standard architecture, EISA) bus or the like. The bus can be divided into address bus, data bus, control bus and so on. For ease of presentation, only one thick line is used in FIG. 4, but it does not mean that there is only one bus or one type of bus.

It should be pointed out that the structure shown in FIG. 4 does not constitute a limitation on the communication device 40. In addition to the components shown in FIG. 4, the communication device 40 may include more or less components than those shown in the figure, or a combination of certain some components, or a different arrangement of components.

As shown in FIG. 5 , it is a schematic flowchart of a fault processing method provided by an embodiment of the present application. The method shown in FIG. 5 can be applied to the fault handling system shown in FIG. 2 or FIG. 3 . The method shown in FIG. 5 is applied to the second network device. The second network device is connected in communication with the first network device. Optionally, the second network device communicates with the first network device through BGP. The second network device may be any one of the network-side network devices in FIG. 2 or FIG. 3 . The first network device may be any one of the network-side network devices in FIG. 2 or FIG. 3 except the second network device.

Optionally, the second network device and the first network device are EVPN neighbors. EVPN neighbor, usually refers to the neighbor relationship between PE devices. EVPN neighbors can also communicate through established tunnels. The type of the tunnel can be, for example, a label distribution protocol (LDP) tunnel, a virtual extensible local area network (VXLAN) protocol tunnel, and the like. Optionally, the second network device and the first network device are PE devices.

The method shown in Figure 5 may include the following steps:

S501: The second network device determines that the route to the MAC address is unreachable, where the MAC address is the MAC address of the user-side network device or the user host connected to the first network device.

For example, referring to FIG. 1, the second network device may be PE device 2, the first network device may be PE device 1, the network side network device may be switch 1, CE device 1A or CE device 2A, and the user host may be CE device 1A Connected user host or CE device 1B connected user host.

For example, referring to FIG. 2 or FIG. 3 , the second network device may be the network-side network device 204 , the first network device may be any one of the network-side network devices 201 to 203 , and the user-side network device may be the network On the side network device 205 , the user host may be the user host 208 . Alternatively, with reference to FIG. 2 or FIG. 3 , the second network device may be the network-side network device 201 , the first network device may be the network-side network device 204 , and the user-side network device may be the network-side network device 206 or the network-side user equipment 207 , the user host can be any one of the user hosts 209-211.

The MAC address is the MAC address of any user-side network device or any user host connected to the first network device. A route to a MAC address, or a route to a MAC address, refers to a route whose destination MAC address is the MAC address. For example, the route to the MAC address may be any route in the local routing table maintained by the second network device.

It should be noted that, for convenience of description below, a route whose destination MAC address is a MAC address is referred to as a route to the MAC address, or a route to the MAC address. The unified description is provided here and will not be described below.

Optionally, S501 can be implemented in the following ways:

Mode 1: When the third network device fails, or the link between the first network device and the third network device fails, the second network device receives the first message from the first network device, and determines the MAC according to the first message. The route for the address is unreachable. The third network device is a user-side network device connected to the first network device.

The third network device may be any user-side network device directly or indirectly connected to the first network device, such as a switch or a CE device. For example, referring to FIG. 1 , if the first network device is PE device 1 , the third network device may be CE device 1A or CE device 1B or switch 1 . For another example, referring to FIG. 2 or FIG. 3 , if the first network device is any one of the network-side network devices 201 to 203 , the third network device may be the user-side network device 205 .

The first message is received by the second network device from the first network device in the state of "the third network device is faulty, or the link between the first network device and the third network device is faulty", and is used to determine the Route unreachable message for the MAC address. This embodiment of the present application does not limit the form of the first message to indicate unreachability, as long as the second network device can determine that the MAC route is unreachable based on the first message.

In an example, the second network device receives a first message sent by the first network device, where the first message is used to indicate an unreachable route, and the unreachable route is determined according to the first message. The unreachable route includes the route in S501. The first network device may send the first message to the second network device when it is determined that the third network device is faulty or the link between the first network device and the third network device is faulty. Wherein, the embodiment of the present application does not uniquely limit which information the first message carries to indicate an unreachable route. In a possible situation, the first message may be MAC withdraw route, such as withdraw type ad-route route.

In another example, the second network device receives a first message sent by the first network device, where the first message is used to indicate a currently reachable route through the first network device. The second network device compares the currently reachable route indicated by the first message with the stored reachable route, so as to determine that the state in the local routing table has actually changed to an unreachable route. The determined unreachable route includes the route in S501. In this example, the first network device may send the first message to the second network device when the third network device fails, or when the link between the first network device and the third network device fails.

In yet another example, the second network device receives a first message sent by the first network device, where the first message is used to indicate a failure of the third network device, or a failure of a link between the first network device and the third network device.

Wherein, the embodiment of the present application does not uniquely define what information the first message carries to indicate the failure of the third network device, or the failure of the link between the first network device and the third network device. For example, the first message may carry information for notifying the failure of the third network device, or information for notifying the failure of the link between the first network device and the third network device. For another example, in addition to carrying the information used to announce the above-mentioned “information about the failure of the third network device, or the information used to indicate the failure of the link between the first network device and the third network device”, the first message may also carry information through A currently reachable route of the first network device, or a currently unreachable route through the first network device, and the like.

This embodiment of the present application does not uniquely limit the type of the first message. For example, the first message may be a BGP Update message.

Optionally, in addition to the first network device, one or more other network devices are also connected to the user-side network device having the MAC address. At this time, the way 1 may include: when the third network device fails, or when the link between the first network device and the third network device fails, the second network device receives the first message from the first network device, and receives the first message from the first network device. The other one or more network devices respectively receive the corresponding one or more second messages. The second network device determines that the route of the MAC address is unreachable according to the first message and the one or more second messages.

This optional implementation provides a method for determining that the route of the MAC address is unreachable when the fault handling method provided by the embodiment of the present application is applied to a multi-homing scenario. Specifically, the third network device is connected to multiple network-side network devices, and the third network device is multi-homed to access network-side network devices. The plurality of network side network devices include a first network device.

The difference between the second message and the first message here is to distinguish messages sent by different network devices. Therefore, for a specific implementation manner of the second message, reference may be made to the relevant description of the first message above, which will not be repeated here.

In an example, if the third network device is multi-homed to multiple network-side network devices, the second network device may receive the first message sent by each network-side network device in the multiple network-side network devices / In the case of the second message, it is determined that the route in S501 is unreachable.

For example, based on FIG. 2 , assuming that the first network device is the network device 201 on the network side and the second network device is the network device 204 on the network side, the unreachable route in S501 may be the route of the user-side network device 205 or the user host 208 route. Since the user-side network device (ie, the user-side network device 205 ) or the user-side network device (ie, the user-side network device 208 ) with the MAC address is also connected to the network-side network devices 202 and 203 , the user-side network device 205 and the network-side network device When the link between 201 is faulty, the packet to be sent to the user-side network device 205 or the user host 208 may be forwarded via the network-side network device 202 or the network-side network device 203 . For example, in an EVPN multi-homing and multi-active scenario, if a CE device serving as a user-side network device is multi-homed to multiple network-side network devices, the CE device can receive packets through the multiple network-side network devices. Therefore, assuming that the third network device is the user-side network device 205, the network-side network device 204 may only consider that the user-side network device 204 receives the first message or the second message sent by the network-side network devices 201-203, respectively. The route to the MAC address of the side network device 205 is unreachable or the route to the MAC address of the user host 208 is unreachable.

Manner 2: The second network device determines that the route of the MAC address is unreachable according to determining that the state of the first network device is faulty. Manner 2 can be understood as: in the case that the second network device actively determines that the state of the first network device is faulty, it determines that the route of the MAC address is unreachable.

Optionally, the second network device determines that the state of the first network device is faulty according to the detection packet sent to the first network device. Specifically, the second network device may send a detection packet to the first network device, and does not receive a response packet for the detection packet within a preset period of time (eg, a preset period of time from sending the detection packet). When , it is determined that the state of the first network device is faulty. For example, the second network device may send a detection packet to the first network device based on a bidirectional forwarding detection (BFD) protocol or a connection fault management (connectivity fault management, CFM) protocol or the like.

Optionally, in addition to the first network device, one or more other network devices are also connected to the user-side network device or user host with the MAC address. For example, in an EVPN multi-homed multi-active scenario, a CE device is multi-homed to multiple PEs. equipment. At this time, Manner 2 may include: the second network device determines that the route of the MAC address is unreachable according to determining that the states of the first network device and the one or more other network devices are both faulty.

Wherein, for the method for the second network device to determine that the state of one or more other network devices is faulty, reference may be made to the above-mentioned method for determining the state of the first network device to be faulty, which will not be repeated here.

In an example, when multiple network devices are connected to a user-side network device or a user host having the MAC address, the second network device may determine that the MAC address is unreachable when determining that the multiple network devices are all faulty. .

For example, based on FIG. 2 , assuming that the second network device is the network-side network device 204 and the first network device is the network-side network device 201 , the unreachable route in S501 may be the route of the user-side network device 205 , or the user host 208 route. Since the user-side network device (ie, the user-side network device 205 ) or the user host (ie, the user host 208 ) with the MAC address is also connected to the network-side network devices 202 and 203 , the network-side network device 204 can determine the network-side network device 204 When the states of the network devices 201-203 are all faulty, it is determined that the MAC address is unreachable.

S502: In response to the determination in S501, the second network device sets indication information corresponding to the route of the MAC address, where the indication information is used to instruct the second network device not to forward the packet when it receives the message addressed to the MAC address the message. For example, as a possible way of not forwarding the packet, the second network device may discard the packet.

This embodiment of the present application does not limit the specific implementation manner of setting the indication information uniquely, as long as the purpose of instructing the second network device not to forward the message sent to the MAC address can be achieved. The following ways a-c serve as possible examples.

Manner a: Setting the indication information may include: changing the route of the MAC address, so that the second network device does not forward the packet when receiving the packet addressed to the MAC address.

For example, the indication information may be to modify the next hop of the route of the MAC address to NULL0. That is, the identifier of the next hop node included in the route of the MAC address is set to NULL0. For example, based on the above Table 1, assuming that the unreachable route is route 7, the "identification of the next hop corresponding to the destination MAC address" in route 7 is set to NULL0. After this setting, the route can be called a black hole route.

Manner b: Setting the indication information may include: setting an indicator for the route of the MAC address. That is to say, each route in the local routing table corresponds to an indicator, and when the value of the indicator is set to a preset value, based on this, the second network device does not receive a packet addressed to the MAC address. Forward the message. Or, a corresponding indicator is set for at least the MAC address, not necessarily the entire route. When the value of the indicator is set to a preset value, the second network device receives the message sent to the MAC address based on this. The message is not forwarded when the message is sent.

Mode c: Setting the indication information may include: storing the route of the MAC address, or at least the MAC address in an unreachable MAC routing table or a MAC address record table, so that the second network device belongs to the MAC address according to the MAC address. The unreachable MAC routing table or the MAC address record table determines not to forward the packets sent to the MAC address. The indication information may be considered to be the unreachable MAC routing table or the MAC address record table itself.

Optionally, after performing S502, the method may further include the following S503.

S503: The second network device deletes the route of the MAC address.

After the execution of S502, when the second network device receives the packet addressed to the MAC address, it no longer forwards the packet based on the route. Therefore, the route maintained by the second network device becomes a redundant route. Based on this Above, executing S503 helps to release the storage space of the second network device, thereby improving the utilization rate of the storage space.

Optionally, the second network device determines that the route to the MAC address is unreachable for a preset time, or deletes the route to the MAC address according to the setting of the indication information to meet the preset time.

For example, the second network device deletes the route of the MAC address after a preset time from determining that the route of the MAC address is unreachable.

For another example, the second network device deletes the route of the MAC address after a preset time from the determination of the indication information.

It should be noted that, during specific implementation, the second network device may implement the optional solution by setting a timer. For example, when it is determined that the route of the MAC address is unreachable or when the indication information is determined to be set, the timer starts and the timer is set. When the timing time meets the preset time, the route of the MAC address is deleted. Wherein, the timer can be implemented by software, can also be implemented by hardware, and can also be implemented by software combined with hardware.

In an example, the optional implementation manner can be understood as: the second network device delays deleting the route of the MAC address. The delayed deletion here is mainly a relative concept that is different from the immediate deletion in the background art. Understandably, in practical applications, it takes a certain period of time to perform immediate deletion or delayed deletion.

The following describes several implementations of the preset time, which can be at least applied to implementations such as setting the indication information directly related to the route of the MAC address, such as the situation in which the indication information is set for the MAC route in the above-mentioned manner a or manner b:

Implementation 1: The preset time is greater than or equal to the MAC aging time of the user-side network device connected to the second network device.

Wherein, if the second network device is connected to multiple user-side network devices, and the MAC aging times set on the multiple user-side network devices are all different or not identical, the preset time may be greater than or equal to the time corresponding to the multiple user-side network devices. The longest aging time among multiple MAC aging times of the user-side network device.

When the aging time of a MAC route arrives, the user-side network device may delete the MAC route from the MAC routing table. Therefore, before the aging time of the MAC route arrives, the user-side network device may send a packet to the network-side network device connected to it according to the MAC route. The route is deleted, and the user-side network device will no longer send packets to the network-side network device connected to it according to the MAC route. In the example applied to the background technology, the switch 2 may send a packet to the PE device 2 before the aging time of the MAC address of the CE device 1A, so that the MAC address of the CE device 1A may not be found in the local routing table. route, which triggers unknown unicast flooding in the EVPN. After switch 2 reaches the aging time of the MAC address, PE device 2 will not receive the packets sent by switch 2 according to the route of the MAC address, so it will not cause unknown unicast flooding in the EVPN.

Based on this, when the above indication information is set, if the indication information is the type of indication information related to the routing table entry of the MAC address, after the indication information is set, it does not reach the user-side network device connected to the second network device. Before the set maximum MAC aging time, the MAC route is deleted. Although it can ensure that the unknown unicast will not be flooded in the EVPN before the route is deleted, it cannot guarantee that the unknown unicast will not be caused after the route is deleted. Flood in EVPN. Therefore, it may be considered that the preset time is greater than or equal to the MAC aging time of the user-side network device connected to the second network device.

Implementation Mode 2: The preset time is greater than or equal to the failure detection period of the user-side network device connected to the second network device, and the failure detection period is a period used to detect whether other user-side network devices in the fault handling system are faulty.

Wherein, if the second network device is connected to multiple user-side network devices, and the fault detection periods of different user-side network devices are different or not completely the same, the preset time may be greater than or equal to the multiple user-side network devices. The longest fault detection period in the fault detection period.

The user-side network device can periodically detect whether other user-side network devices in the fault handling system are faulty. Applied to the example in the background art, the switch 2 can periodically detect whether the switch 1 is faulty.

If at the beginning of a failure detection period, one user-side network device determines that another user-side network device is not faulty, then, during the failure detection period, the user-side user equipment may also send a message to the other user-side network device. message. Based on this, before the end of a fault detection period, if the network side network device connected to the other user side network device deletes the local route of the other user side network device, the network side network device will receive the When the packet of the other user-side network device cannot find the corresponding route, unknown unicast flooding in the EVPN occurs. When the next fault detection period comes, the user equipment on the user side can detect the failure of the other user side network equipment, so it will not send packets to the other user side network equipment. The network device on the network side connected to the network device will not receive the packet, so unknown unicast flooding in the EVPN will not occur.

The example applied to the background art, at the beginning of a fault detection period, the switch 2 determines that the switch 1 is not faulty, then before the fault detection period ends, even if the switch 1 is faulty, the switch 2 cannot sense it. Therefore, the switch 2 may also send a message to switch 1. If PE device 2 deletes the local route of switch 1 during the fault detection period, after the packet reaches PE device 2, PE device 2 cannot find the local route of switch 1 in the stored routing table, and Causes unknown unicast to flood in EVPN.

Based on this, after setting the indication information associated with the MAC route, timing can be performed, and the second network device deletes the MAC route only after reaching or exceeding the failure detection period of the user-side network device connected to the second network device. In order to ensure that the unknown unicast traffic flooding caused by the premature deletion of the MAC route will not be caused.

Implementation mode 3: The preset time is greater than or equal to the minimum value between the MAC aging time of the user-side network device connected to the second network device and the failure detection period of the user-side network device connected to the second network device. The period used to detect whether other user-side network devices in the fault handling system are faulty.

Implementation mode 3 refers to the MAC aging time of the user-side network device connected to the second network device and the failure detection period of the user-side network device connected to the second network device. It is not repeated here.

In the fault handling method provided by the embodiment of the present application, the second network device determines that the route to the MAC address is unreachable, and the MAC address may be the MAC address of the user-side network device or user host connected to the first network device; in response to the determination, The second network device sets indication information corresponding to the route of the MAC address, where the indication information is used to instruct the second network device not to forward the message when receiving the message addressed to the MAC address. In this way, compared with the technical solution in the background art, since the second network device does not forward the message addressed to the MAC address, the unknown unicast will not be triggered to flood in the EVPN, thereby reducing the waste of communication resources.

The solutions provided by the embodiments of the present application have been introduced above mainly from the perspective of methods. In order to realize the above-mentioned functions, it includes corresponding hardware structures and/or software modules for executing each function. Those skilled in the art should easily realize that the present application can be implemented in hardware or a combination of hardware and computer software with the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein. Whether a function is performed by hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

In this embodiment of the present application, the fault processing apparatus (such as the second network device) may be divided into functional modules according to the foregoing method examples. For example, each functional module may be divided corresponding to each function, or two or more functions may be integrated in in a processing module. The above-mentioned integrated modules can be implemented in the form of hardware, and can also be implemented in the form of software function modules. It should be noted that, the division of modules in the embodiments of the present application is schematic, and is only a logical function division, and there may be other division manners in actual implementation.

As shown in FIG. 6 , FIG. 6 shows a schematic structural diagram of a second network device 60 provided by an embodiment of the present application. The second network device 60 is configured to execute the above-mentioned fault handling method, for example, execute the fault handling method shown in FIG. 5 . For example, the second network device 60 may include a determining unit 601 and a setting unit 602 .

The determining unit 601 is configured to determine that the route to the MAC address is unreachable, where the MAC address is the MAC address of the user-side network device or the user host connected to the first network device. A setting unit 602 is configured to, in response to the determination, set indication information corresponding to the route of the MAC address. The indication information is used to instruct the second network device not to forward the packet when it receives the packet addressed to the MAC address. For example, in conjunction with FIG. 5 , the determining unit 601 may be used to perform S501, and the setting unit 602 may be used to perform S502.

Optionally, the second network device 60 further includes: a deletion unit 603, configured to delete the route of the MAC address after the setting unit 602 sets the indication information corresponding to the route of the MAC address. For example, in conjunction with FIG. 5, the deletion unit 603 may be used to perform S503.

Optionally, the deleting unit 603 is specifically configured to: determine that the route to the MAC address is unreachable for a preset time, or delete the route of the MAC address according to the condition that the setting instruction information meets the preset time.

Optionally, the second network device 60 further includes: a receiving unit 604, configured to receive the first network device from the first network device when the third network device fails, or when the link between the first network device and the third network device fails. a message. In this case, the determining unit 601 is specifically configured to: determine that the route of the MAC address is unreachable according to the first message. The third network device is a user-side network device connected to the first network device.

Optionally, in addition to the first network device, one or more other network devices are also connected to the user-side network device or user host having the MAC address. In this case, the receiving unit 604 is specifically configured to: receive the first message from the first network device, and receive one or more second messages from the other one or more network devices. The determining unit 601 is specifically configured to: determine that the route of the MAC address is unreachable according to the first message and the one or more second messages.

Optionally, the determining unit 601 is specifically configured to: determine that the route of the MAC address is unreachable according to determining that the state of the first network device is faulty.

Optionally, in addition to the first network device, one or more other network devices are also connected to the user-side network device or user host having the MAC address. In this case, the determining unit 601 is specifically configured to: determine that the route of the MAC address is unreachable according to determining that the states of the first network device and the one or more other network devices are both faulty.

Optionally, the determining unit 601 is further configured to: determine that the state of the first network device is faulty according to the detection packet sent to the first network device.

Optionally, the third network device includes a switch.

Optionally, the first message is a BGP Update message.

Optionally, the indication information includes that the next hop of the route of the MAC address is NULL0.

Optionally, the first network device and the second network device are EVPN neighbors.

Optionally, the first network device and the second network device are PE devices.

For the specific description of the foregoing optional manners, reference may be made to the foregoing method embodiments, which will not be repeated here. In addition, the explanation of any of the second network devices 60 provided above and the description of the beneficial effects may refer to the corresponding method embodiments above, which will not be repeated.

As an example, with reference to FIG. 4 , some or all of the functions implemented in the determining unit 601 , the setting unit 602 and the deleting unit 603 in the second network device 60 may be executed by the processor 401 in FIG. 4 in the memory 402 in FIG. 4 . program code implementation. The receiving unit 604 may be implemented by the receiving unit in the communication interface 403 in FIG. 4 .

An embodiment of the present application further provides a fault processing system, where the fault processing system includes a first network device and a second network device, the second network device may be any of the second network devices 60 provided above, and the first network device 60 A network device may be any PE device shown in FIG. 1 that is not the second network device, or any network-side network device shown in FIG. 2 or FIG. 3 that is not the second network device. The system may further include a third network device, for example, the third network device may be any switch or CE device shown in FIG. 1 , or any user-side network device shown in FIG. 2 or FIG. 3 .

Embodiments of the present application further provide a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program runs on a computer, the computer is made to execute any one of the above-mentioned methods. A method performed by a second network device.

For the explanation and description of the beneficial effects of any fault handling system and computer-readable storage medium provided above, reference may be made to the above-mentioned corresponding embodiments, which will not be repeated here.

The embodiment of the present application also provides a chip. The chip integrates a control circuit and one or more ports for implementing the functions of the second network device 60 described above. Optionally, for the functions supported by the chip, reference may be made to the above, which will not be repeated here. Those of ordinary skill in the art can understand that all or part of the steps for implementing the above embodiments can be completed by instructing relevant hardware through a program. The described program can be stored in a computer-readable storage medium. The above-mentioned storage medium may be a read-only memory, a random access memory, or the like. The above-mentioned processing unit or processor can be a central processing unit, a general-purpose processor, a specific integrated circuit (application specific integrated circuit, ASIC), a microprocessor (digital signal processor, DSP), a field programmable gate array (field programmable gate array, FPGA) or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof.

The embodiments of the present application also provide a computer program product containing instructions, when the instructions are run on a computer, the instructions cause the computer to execute any one of the methods in the foregoing embodiments. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of the present application are generated in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable device. Computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server, or data center over a wire (e.g. coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (eg infrared, wireless, microwave, etc.) means to transmit to another website site, computer, server or data center. Computer-readable storage media can be any available media that can be accessed by a computer or data storage devices including one or more servers, data centers, etc., that can be integrated with the media. Useful media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media (eg, SSDs), and the like.

It should be noted that the above-mentioned devices for storing computer instructions or computer programs provided in the embodiments of the present application, such as but not limited to, the above-mentioned memory, computer-readable storage medium, and communication chip, etc., are all non-transitory (non-transitory) .

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed application, from review of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that these measures cannot be combined to advantage. Although the application has been described in conjunction with specific features and embodiments thereof, various modifications and combinations may be made without departing from the spirit and scope of the application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined by the appended claims, and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of this application.

Claims (24)

1. A fault handling method, characterized in that a first network device and a second network device are connected in communication, the method comprising:

   The second network device determines that the route to the media access control MAC address is unreachable, and the MAC address is the MAC address of the user-side network device or user host connected to the first network device;

   In response to the determination, the second network device sets indication information corresponding to the route of the MAC address, where the indication information is used to indicate that the second network device receives a message sent to the MAC address The message is not forwarded when the message is sent.
2. The method according to claim 1, wherein after the second network device sets the indication information corresponding to the route of the MAC address, the method further comprises:

   The second network device deletes the route of the MAC address.
3. The method according to claim 2, wherein deleting the route of the MAC address by the second network device comprises:

   The second network device determines that the route to the MAC address is unreachable for a preset time, or determines that the setting of the indication information satisfies the preset time, and deletes the route to the MAC address.
4. The method according to any one of claims 1-3, wherein determining, by the second network device, that the route to the MAC address is unreachable, comprising:

   When the third network device fails, or the link between the first network device and the third network device fails, the second network device receives the first message from the first network device, and sends the message according to the The first message determines that the route of the MAC address is unreachable, wherein the third network device is a user-side network device connected to the first network device; or,

   The second network device determines that the route of the MAC address is unreachable according to determining that the state of the first network device is faulty.
5. The method according to claim 4, wherein, in addition to the first network device, one or more other network devices are also connected to the user-side network device or the user host having the MAC address;

   The second network device receives a first message from the first network device, and determines, according to the first message, that the route of the MAC address is unreachable, including:

   the second network device receives a first message from the first network device, and receives one or more second messages from the other one or more network devices;

   The second network device determines, according to the first message and the one or more second messages, that the route of the MAC address is unreachable; or,

   The second network device determines that the route of the MAC address is unreachable according to determining that the state of the first network device is faulty, including:

   The second network device determines that the route of the MAC address is unreachable according to determining that the states of the first network device and the other one or more network devices are both faulty.
6. The method according to claim 4 or 5, wherein the method further comprises:

   The second network device determines that the state of the first network device is faulty according to the detection message sent to the first network device.
7. The method according to any one of claims 4 to 6, wherein the third network device comprises a switch.
8. The method according to any one of claims 4 to 7, wherein the first message is a Border Gateway Protocol update BGP Update message.
9. The method according to any one of claims 1 to 8, wherein the indication information comprises that the next hop of the route of the MAC address is NULL0.
10. The method according to any one of claims 1 to 9, wherein the first network device and the second network device are Ethernet private virtual network EVPN neighbors.
11. The method according to any one of claims 1 to 10, wherein the first network device and the second network device are operator edge PE devices.
12. A second network device, characterized in that the first network device is communicatively connected to the second network device, and the second network device includes:

    a determining unit, configured to determine that the route to the MAC address of the media access control is unreachable, where the MAC address is the MAC address of the user-side network device or user host connected to the first network device;

    a setting unit, configured to, in response to the determination, set indication information corresponding to the route of the MAC address, where the indication information is used to indicate that the second network device is receiving a packet destined for the MAC address the message is not forwarded.
13. The second network device according to claim 12, wherein the second network device further comprises:

    A deletion unit, configured to delete the route of the MAC address after the setting unit sets the indication information corresponding to the route of the MAC address.
14. The second network device according to claim 13, wherein,

    The deletion unit is specifically configured to: determine that the route to the MAC address is unreachable for a preset time, or delete the route of the MAC address when it is determined that the indication information is set to meet the preset time.
15. The second network device according to any one of claims 12-14, wherein,

    The second network device further includes: a receiving unit, configured to receive a message from the first network device when the third network device fails, or when the link between the first network device and the third network device fails. receiving a first message; the determining unit is specifically configured to: determine, according to the first message, that the route of the MAC address is unreachable, wherein the third network device is a user-side network connected to the first network device equipment; or,

    The determining unit is specifically configured to: determine that the route of the MAC address is unreachable according to determining that the state of the first network device is faulty.
16. The second network device according to claim 15, wherein, in addition to the first network device, one or more other network devices are also connected to the user-side network device or the user host having the MAC address;

    The receiving unit is specifically configured to: receive a first message from the first network device, and receive one or more second messages from the other one or more network devices; the determining unit is specifically configured to: according to the the first message and the one or more second messages, it is determined that the route of the MAC address is unreachable; or,

    The determining unit is specifically configured to: determine that the route of the MAC address is unreachable according to determining that the states of the first network device and the other one or more network devices are both faulty.
17. The second network device according to claim 15 or 16, wherein,

    The determining unit is further configured to: determine that the state of the first network device is faulty according to the detection message sent to the first network device.
18. The second network device according to any one of claims 15 to 17, wherein the third network device comprises a switch.
19. The second network device according to any one of claims 15 to 18, wherein the first message is a Border Gateway Protocol Update BGP Update message.
20. The second network device according to any one of claims 12 to 19, wherein the indication information includes that the next hop of the route of the MAC address is NULL0.
21. The second network device according to any one of claims 12 to 20, wherein the first network device and the second network device are Ethernet private virtual network EVPN neighbors.
22. The second network device according to any one of claims 12 to 21, wherein the first network device and the second network device are operator edge PE devices.
23. A fault handling device, comprising: a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call the computer program to execute any one of claims 1-11. method.
24. A computer-readable storage medium, characterized in that, a computer program is stored in the computer-readable storage medium, and when the computer program is executed on a computer, the computer is made to execute any one of claims 1-11. method described.

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