CN116846817A

CN116846817A - A message processing method, communication system and related devices

Info

Publication number: CN116846817A
Application number: CN202210301375.6A
Authority: CN
Inventors: 张文锋
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2023-10-03

Abstract

The application discloses a message processing method, a communication system and a related device, which are applied to a two-layer virtual private network (L2 VPN), wherein the L2VPN comprises a first network and a second network, the first network comprises a first operator edge PE device and a second PE device, the second network comprises a third PE device and a fourth PE device, and the second PE device is in communication connection with a user edge CE device, and the method comprises the following steps: the first PE device determines that all pseudo wires PW between the first PE device and the second PE device have faults; the first PE device sends out a fault indication, the fault indication is used for indicating the third PE device to switch the service flow of the CE device from the first path to the second path, the first path comprises a link between the third PE device and the first PE device, the second path comprises a link between the third PE device and the fourth PE device and a target link between the fourth PE device and the second PE device, and therefore the fault when all PW between the PE device at the user side and the PE device at the network side in the network are unreachable is solved.

Description

Message processing method, communication system and related device

Technical Field

Embodiments of the present application relate to the field of communications technologies, and in particular, to a method for processing a message, a communication system, and a related device.

Background

A single operator's network, when large enough, will divide the network into multiple subnets, each of which manages a certain defined number of network devices.

In order to improve service reliability, two Provider Edge (PE) devices are selected by different networks to transmit a message on a user side, and a Multi-device automatic protection switching (MC-APS) mechanism and a Multi-device link aggregation group (MC-LAG) mechanism are deployed between PE devices from different networks to improve service reliability. Taking two networks as an example, two groups of PE devices with MC-APS mechanism and MC-LAG mechanism are deployed in the two networks, and each group of PE devices is respectively composed of two PE devices from different networks. When one PE device or the communication link of the PE device group fails, the message is transmitted by the other group of interworking PEs.

When a communication link of a working PE device group between two networks is normally reachable, but all Pseudowires (PW) between a network side PE device of a certain network (i.e. a PE device connected to a PE device in a peer network) and a user side PE device (i.e. a PE device connected to a user edge device in the network) fail, the MC-APS mechanism and the MC-LAG mechanism cannot take effect on the failure, and a message between the two networks cannot be transferred.

Disclosure of Invention

The embodiment of the application provides a message processing method, a communication system and a related device, which are used for solving PW faults of a network.

In a first aspect, an embodiment of the present application provides a method for processing a packet, which is applied to a Layer 2VPN (Layer 2Virtual Private Network), where a first network includes a first PE device and a second PE device, and the second network includes a third PE device and a fourth PE device, and the second PE device is communicatively connected to a Customer Edge (CE) device in the first network. In the application, the first PE equipment does not have faults, and the first PE equipment and the third PE equipment can normally communicate with each other, namely, the message of the third PE equipment can be transmitted to the first PE equipment. However, all PWs between the first PE device and the second PE device have failed, so that the message from the second PE device cannot reach the third PE device through forwarding by the first PE device, that is, the third PE device cannot receive the message from the second PE device. However, the third PE device cannot determine the reason why it cannot receive the message from the second PE device, either because a PW failure occurs or because the second PE device does not send a message to the third PE device at all; on the other hand, since the message of the third PE device may be normally transmitted to the first PE device, the third PE device may consider that the PW of the message transmission remains normal. In general, the third PE device cannot perceive that all PWs between the first PE device and the second PE device have failed, regardless of whether it is an upstream messaging service or a downstream messaging service.

All PWs between the first PE device and the second PE device refer to all PWs capable of performing message interworking between the first PE device and the second PE device, including PWs directly connected to the first PE device and the second PE device, and segmented PWs bridged by other network devices between the first PE device and the second PE device.

In the application, the first PE device periodically checks the connectivity of all PW between the first PE device and the second PE device, thereby determining whether each PW between the first PE device and the second PE device has faults. In some possible implementations, the first PE device may detect the PW based on an operation administration and maintenance (operation administration and maintenance, OAM) mechanism of the PW. By way of example, taking the first PE device as the sink device and the second PE device as the source PE device, when the sink device fails to receive the detection message sent by the source device for 3 consecutive periods, the connection state is considered to be Down, and then it can be determined that the PW between the sink device and the source device fails, that is, the traffic between the sink device and the source device is not reachable.

And after the first PE device detects that all PW between the first PE device and the second PE device have faults, notifying a third PE device in the second network, namely the first PE device needs to send out a fault indication. In particular, the first PE device may send out the fault indication in various implementations, which is not limited in the present application.

After the first PE device sends out a fault indication, the third PE device senses the fault, and determines that the service flow between the third PE device and the second PE device cannot be communicated, the third PE device triggers a protection switching mechanism of the MC-LAG to execute switching action, the third PE device switches the message transmission service of the second network to the fourth PE device for transmission, namely the service flow from the first network is transmitted to the second network through a link between the third PE device and the fourth PE device, and the service flow sent out in the second network is transmitted to the first network through a link between the third PE device and the fourth PE device. Thus, the message transmission service between the second network and the first network (i.e., the service traffic taking the CE device in the first network as the source device or the sink device) is switched from the first path to the second path for transmission, where the first path includes a link between the third PE device and the first PE device, and the second path includes a link between the third PE device and the fourth PE device and a target link between the fourth PE device and the second PE device.

In the application, when a communication link between PE devices working between two networks is normally reachable, but all PWs between a network side PE device (namely PE device connected with PE devices in an opposite end network) and a user side PE device (namely PE device connected with CE devices in the network) are unreachable, the network side PE device of the network can sense the fault and trigger the PE devices of the opposite end network to switch, thereby solving the PW fault of the network.

Based on the first aspect, in an optional implementation manner, the first network further includes a fifth PE device, and an MC-LAG is disposed between the first network and the second network, where the MC-LAG includes a first link aggregation group LAG between the first PE device and the third PE device, and a second LAG between the fifth PE device and the fourth PE device. Therefore, the third PE device may transmit the packet between the first network and the second network through the second LAG, that is, the target link after the switching in the present application includes the second LAG.

The first LAG and the second LAG may be used for message transmission between the first network and the second network, where one LAG is used as a working LAG (for example, a LAG between the first PE device and the third PE device in the present application), the other LAG is used as an alternative LAG (for example, a LAG between the fifth PE device and the fourth PE device in the present application), and after the MC-LAG switching protection is triggered by the working LAG, the message between the first network and the second network is transmitted by the alternative LAG. Further, an MC-APS mechanism is deployed between the first PE device and the fifth PE device in the first network, that is, a dual-node interconnection pseudowire (dual node interconnection PW, DNI-PW) is established between the first PE device and the fifth PE device, and similarly, an MC-APS mechanism is deployed between the third PE device and the fourth PE device in the second network, that is, a DNI-PW is established between the third PE device and the fourth PE device, and after the MC-LAG switching protection is triggered, the first PE device and the fifth PE device perform a negotiation switching action through the DNI-PW, or the third PE device and the fourth PE device perform a negotiation switching action through the DNI-PW.

Based on the first aspect, in an optional implementation manner, the first PE device sets down a link aggregation control (link aggregation control protocol, LACP) protocol corresponding to the first LAG, so that the first LAG is not available. The third PE device at the other end of the first LAG may sense that the LACP protocol of the first LAG has been down, so that the third PE device triggers the protection switching mechanism of the MC-LAG.

Based on the first aspect, in an optional implementation manner, the first PE device turns off all ports corresponding to the first LAG established between the first PE device and the third PE device. In the application, turning off the port corresponding to the LAG means that the port corresponding to the LAG is forbidden to enable to send out the optical signal, the third PE device cannot receive the optical signal from the first PE device, and the third PE device triggers the protection switching mechanism of the MC-LAG.

Based on the first aspect, in an optional implementation manner, since the traffic flow can be exchanged normally between the first PE device and the third PE device, the first PE device may send a failure indication message with the second PE device, where the failure indication message includes first PW information, and the first PW information indicates that all pseudowires PW between the first PE device and the second PE device have failed. After the third PE device receives the fault indication message, the first PW information is obtained through analysis, so that the fault is determined, and a protection switching mechanism of the MC-LAG is triggered.

Based on the first aspect, in an alternative implementation manner, even if all PWs between the first PE device and the second PE device have failed, the first PE device continues to periodically detect the PW between the first PE device and the second PE device through the OAM mechanism. When the first PE device detects that the fault of at least one PW between the first PE device and the second PE device is recovered, the first PE device sends out a fault recovery instruction, after the third PE device receives the fault recovery instruction, the protection switching mechanism is triggered again, the fourth PE device switches the message transmission service to the third PE device again, namely, the service flow between the first network and the second network is transmitted through a first path (namely, a link between the third PE device and the first PE device), and the recovered PW between the first PE device and the second PE device is transmitted.

In the application, the first PE device can continuously detect the connectivity of PW between the first PE device and the second PE device so as to continuously work after the failed PW is recovered, thereby improving the resolving efficiency of PW failure

Based on the first aspect, in an optional implementation manner, in response to a failure of at least one PW between the first PE device and the second PE device being recovered, the first PE device takes a LACP protocol corresponding to the first LAG as a revocation device (i.e., a LACP protocol is set UP), which is used as a third PE device at the other end of the first LAG, so that it can be perceived that the LACP protocol state of the first LAG has been revoked (i.e., set UP), and the third PE device triggers a protection switching mechanism of the MC-LAG.

Based on the first aspect, in an optional implementation manner, in response to a recovery of a fault of at least one PW between the first PE device and the second PE device, the first PE device opens all ports corresponding to the first LAG, that is, the first PE device enables the ports corresponding to the first LAG to emit light, the third PE device may receive an optical signal from the first PE device, and the third PE device triggers a protection switching mechanism of the MC-LAG.

Based on the first aspect, in an optional implementation manner, since the traffic flow can be exchanged between the first PE device and the third PE device normally, when a failure of at least one PW between the first PE device and the second PE device has been recovered, the first PE device may send a failure recovery indication to the second PE device, where the failure recovery indication includes second PW information, and the second PW information indicates that the failure of the at least one PW has been recovered, so as to notify the third PE device to perform protection switching. After receiving the fault recovery instruction, the third PE device analyzes the fault recovery instruction to obtain second PW information, so that it is determined that at least one PW fault is recovered, and a protection switching mechanism of the MC-LAG is triggered.

Based on the first aspect, in an optional implementation manner, since a first LAG is established between the first PE device and the third PE device, the recovery instruction packet may be carried in the LACPDU and transmitted through the first LAG.

Based on the first aspect, in an optional implementation manner, the restoration instruction packet is used to indicate that at least one PW between the first PE device and the second PE device has been restored.

In a second aspect, an embodiment of the present application provides a communication system, where the communication system is applied to a two-layer virtual private network L2VPN, the communication system includes a first provider edge PE device and a second PE device in a first network, and a third PE device and a fourth PE device in the second network, where the second PE device is communicatively connected to a customer edge CE device, and the first PE device is configured to determine that all pseudowires PW between the first PE device and the second PE device have a failure, and send a failure indication, where the failure indication is configured to instruct the third PE device to switch traffic of the CE device from a first path to a second path, where the first path includes a link between the third PE device and the first PE device, and the second path includes a link between the third PE device and the fourth PE device, and a target link between the fourth PE device and the second PE device;

and the third PE equipment is used for switching the service flow from the first path to the second path according to the fault information.

Based on the second aspect, in an optional implementation manner, the first network further includes a fifth PE device, a cross-device link aggregation group MC-LAG is disposed between the first network and the second network, the MC-LAG includes a first link aggregation group LAG between the first PE device and the third PE device, and a second LAG between the fifth PE device and the fourth PE device, and the target link includes the second LAG.

Based on the second aspect, in an optional implementation manner, when the first PE device issues a fault indication, the method is specifically used for: and setting down the link aggregation control LACP protocol corresponding to the first LAG.

Based on the second aspect, in an optional implementation manner, when the first PE device issues a fault indication, the method is specifically used for: and all ports corresponding to the first LAG are turned off.

Based on the second aspect, in an optional implementation manner, when the first PE device issues a fault indication, the method is specifically used for: and sending a fault indication message to the second PE equipment, wherein the fault indication message comprises first PW information, and the first PW information indicates that all pseudo wires PW between the first PE equipment and the second PE equipment have faults.

Based on the second aspect, in an alternative implementation manner, the first PE device is further configured to: when at least one PW between the first PE device and the second PE device is recovered, the first PE device sends out a fault recovery instruction, and the fault recovery instruction is used for indicating the third PE device to transmit the service flow through the first path.

Based on the second aspect, in an optional implementation manner, when the first PE device sends a recovery instruction, the method is specifically used for: and setting the LACP protocol corresponding to the first LAG up.

Based on the second aspect, in an optional implementation manner, when the first PE device sends a recovery instruction, the method is specifically used for: and opening all ports corresponding to the first LAG.

Based on the second aspect, in an optional implementation manner, when the first PE device issues a fault recovery instruction, the method is specifically used for: and sending a fault recovery instruction to the second PE equipment, wherein the fault recovery instruction comprises second PW information, and the second PW information indicates that at least one PW has recovered from the fault.

The content of the information interaction and the execution process of the embodiment shown in the present aspect is based on the same concept as the embodiment shown in the first aspect, so the description of the beneficial effects shown in the present aspect is shown in the above first aspect, and details are not repeated here.

In a third aspect, an embodiment of the present application provides a network device, configured to serve as a first provider edge PE device, and applied to a two-layer virtual private network L2VPN, where the L2VPN includes a first network and a second network, the first network includes a first PE device and a second PE device, the second network includes a third PE device and a fourth PE device, and the second PE device is communicatively connected to a customer edge CE device in the first network, where the network device includes:

A determining unit, configured to determine that all pseudowires PW between the first PE device and the second PE device have a failure;

the processing unit is used for sending out a fault indication, and the fault indication is used for indicating the third PE equipment to switch the service flow of the CE equipment from the first path to the second path, wherein the first path comprises a link between the third PE equipment and the first PE equipment, and the second path comprises a link between the third PE equipment and the fourth PE equipment and a target link between the fourth PE equipment and the second PE equipment.

Based on the third aspect, in an optional implementation manner, the first network further includes a fifth PE device, a cross-device link aggregation group MC-LAG is disposed between the first network and the second network, the MC-LAG includes a first link aggregation group LAG between the first PE device and the third PE device, and a second LAG between the fifth PE device and the fourth PE device, and the target link includes the second LAG.

Based on the third aspect, in an optional implementation manner, the processing unit is specifically configured to: and setting down the link aggregation control LACP protocol corresponding to the first LAG.

Based on the third aspect, in an optional implementation manner, the processing unit is specifically configured to: and all ports corresponding to the first LAG are turned off.

Based on the third aspect, in an optional implementation manner, the processing unit is specifically configured to: and sending a fault indication message to the second PE equipment, wherein the fault indication message comprises first PW information, and the first PW information indicates that all pseudo wires PW between the first PE equipment and the second PE equipment have faults.

Based on the third aspect, in an optional implementation manner, the processing unit is further configured to, when at least one PW between the first PE device and the second PE device is recovered, send a fault recovery instruction, where the fault recovery instruction is used to instruct the third PE device to transmit traffic through the first path.

Based on the third aspect, in an optional implementation manner, the processing unit is specifically configured to: and setting the LACP protocol corresponding to the first LAG up.

Based on the third aspect, in an optional implementation manner, the processing unit is specifically configured to: and opening all ports corresponding to the first LAG.

Based on the third aspect, in an optional implementation manner, the processing unit is specifically configured to: and sending a fault recovery instruction to the second PE equipment, wherein the fault recovery instruction comprises second PW information, and the second PW information indicates that at least one PW has recovered from the fault.

In a fourth aspect, an embodiment of the present application provides a network device, configured to serve as a first provider edge PE device, and applied to a two-layer virtual private network L2VPN, where the L2VPN includes a first network and a second network, the first network includes a first PE device and a second PE device, the second network includes a third PE device and a fourth PE device, the second PE device is communicatively connected to a customer edge CE device in the first network, and the network device includes:

a memory for storing a program;

a processor coupled to the memory for executing the program in the memory to cause the network device to perform the method of any of the above aspects.

In a fifth aspect, the present application provides a computer readable storage medium having a computer program stored therein, which when run on a computer causes the computer to perform the method of any of the above aspects.

In a sixth aspect, the present application provides a computer program product or computer program comprising computer instructions which, when run on a computer, cause the computer to perform the method of any of the above aspects.

From the above technical solutions, the embodiment of the present application has the following advantages:

The application discloses a message processing method, a communication system and a related device, wherein the method is applied to an L2VPN, the L2VPN comprises a first network and a second network, the first network comprises a first provider edge PE device and a second PE device, the second network comprises a third PE device and a fourth PE device, the second PE device is in communication connection with a customer edge CE device, the method comprises the following steps: the first PE device determines that all pseudo wires PW between the first PE device and the second PE device have faults; the first PE device sends out a fault indication, and the fault indication is used for indicating the third PE device to switch the service flow of the CE device from a first path to a second path, wherein the first path comprises a link between the third PE device and the first PE device, and the second path comprises a link between the third PE device and the fourth PE device and a target link between the fourth PE device and the second PE device. In the application, when a communication link between PE devices working between two networks is normally reachable, but all PWs between a network side PE device (namely PE device connected with PE devices in an opposite end network) and a user side PE device (namely PE device connected with CE devices in the network) in a certain network are unreachable, the network side PE device of the network can sense the fault and trigger the PE devices of the opposite end network to switch, thereby solving the PW fault of the network and ensuring service connectivity.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present application, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a pseudowire Ethernet line type business model;

FIG. 2 is a schematic diagram of a scenario in which a link aggregation group is deployed between two networks;

FIG. 3 is a schematic diagram of a link failure in a link aggregation group between two networks;

FIG. 4 is a schematic diagram of a failure of PE devices in a link aggregation group;

FIG. 5 is a schematic diagram of a scenario of the MC-APS mechanism and the MC-LAG mechanism;

fig. 6 is a schematic diagram of switching protection under the MC-APS mechanism and the MC-LAG mechanism;

FIG. 7 is a schematic diagram of a fault scenario under the MC-APS mechanism and the MC-LAG mechanism;

FIG. 8 is a flow chart of a message processing method according to an embodiment of the application;

fig. 9 is a schematic diagram of a link switching scenario in an embodiment of the present application;

fig. 10 is a schematic structural diagram of a network device according to an embodiment of the present application;

Fig. 11 is a schematic structural diagram of another network device according to an embodiment of the present application.

Detailed Description

Embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. The terminology used in the description of the embodiments of the application herein is for the purpose of describing particular embodiments of the application only and is not intended to be limiting of the application. As one of ordinary skill in the art can know, with the development of technology and the appearance of new scenes, the technical scheme provided by the embodiment of the application is also applicable to similar technical problems.

In the present application, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a alone, a and B together, and B alone, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or plural.

The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented, for example, in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

two-Layer (Layer 2, L2) or three-Layer (Layer 3, L3) client side message butt joint is generally adopted when different operators are in service intercommunication, and information in a home terminal network is not transmitted to an opposite terminal network as much as possible. A single operator's network, when large enough, will divide the network into multiple subnets, each of which manages a certain defined number of network devices.

In the two-Layer virtual private network (Layer 2Virtual Private Network,L2VPN), a Pseudo Wire (PW) is a point-to-point connection established between edge routers, through which the original access mode and the existing IP backbone network can be well fused together, thereby reducing repeated construction of the network and saving operation cost. Pseudowire Ethernet Line (E-Line) service is E-Line service from user side to network side of PW load, and is called remote E-Line service of PW load. Referring to fig. 1, fig. 1 is a schematic diagram of PW E-Line service model. As shown in fig. 1, the source and sink of PW E-Line traffic on a packet transport network (packet transport network, PTN) device are the user network interface (user network interface, UNI) and the network-network interface (NNI), respectively. Taking enterprise 1 and enterprise 2 in fig. 1 as examples, both enterprises have branches in network 1, each branch needs to communicate with headquarters, and business needs to be isolated between enterprise 1 and enterprise 2. At this time, the Ethernet private line service from the user side to the network side of PW load can be configured to meet the communication demands between the branches and headquarters of enterprises 1 and 2, and meanwhile, because different PW loads are adopted by different service flows, the mutual isolation of the services between enterprises is also realized. In this case, the enterprise traffic accessed by the user side is encapsulated into PW for delivery.

In the process of interworking two networks with each other, in order to improve the reliability of message transmission, there are two general methods, which are described below.

Mode 1: referring to fig. 2, fig. 2 is a schematic diagram of a scenario in which a link aggregation group is deployed between two networks. As shown in fig. 2, each of the network 1 and the network 2 selects one Provider Edge (PE) device for communication connection, specifically, a link aggregation group (link aggregation group, LAG) is deployed between two PE devices through multiple links to expand bandwidth, and improve reliability of packet transmission. When one of the links fails, the message can be transmitted through the other link.

LAG is a binding technique that binds multiple physical interfaces into one logical interface, referred to as a Trunk interface, and each physical interface bound together is referred to as a member interface. The major advantages of LAG technology are:

increasing bandwidth: the total bandwidth of the Lag interface is the sum of the bandwidths of all member interfaces, and the bandwidth of the interfaces can be increased by times in this way;

reliability is improved: when a physical link connected with a member interface fails, the flow is switched to other available links, so that the reliability of the whole Lag link is improved;

Load sharing: load sharing can be realized through the Lag interface, the Lag interface distributes traffic to different links and finally reaches the same destination, so that network congestion caused by that all traffic walks the same link can be avoided.

Referring to fig. 3, fig. 3 is a schematic diagram illustrating that a link in a link aggregation group between two networks fails. As shown in fig. 3, two links between the PE1 device in the network 1 and the PE2 device in the network 2 may perform communication, and when one of the links between the PE1 device and the PE2 device fails, a message may be transmitted through the other link.

Referring to fig. 4, fig. 4 is a schematic diagram illustrating a failure of a PE device in a link aggregation group. As shown in fig. 4, when a certain PE device (PE 1 device or PE2 device) fails as a whole, the links related to the PE device are not available, and both links in the LAG fail, so that the message cannot be transmitted through the LAG.

Mode 2: on the basis of the LAG technique of the above scheme 1, in order to further improve service reliability, two PE devices are selected by different networks to perform user-side packet transfer, and a Multi-device automatic protection switching (Multi-Chassis Automatic Protection Switched, MC-APS) mechanism and a Multi-device link aggregation group (Multi-chassis Link Aggregation Group, MC-LAG) mechanism are deployed between PE devices from different networks to improve service reliability. Taking two networks as an example, two groups of PE devices with MC-APS mechanism and MC-LAG mechanism are deployed in the two networks, and each group of PE devices is respectively composed of two PE devices from different networks. When PW of one PE device or PE device group fails, the message is transmitted by another group of intercommunication PE devices.

Referring to fig. 5, fig. 5 is a schematic diagram of a scenario of an MC-APS mechanism and an MC-LAG mechanism, where the MC-APS mechanism and the MC-LAG mechanism cooperate with each other to implement dual homing protection for private line service, as shown in fig. 5. Under the MC-APS mechanism and the MC-LAG mechanism, the deployment architecture of the network 1 is similar to that of the PE devices of the network 2.

MC-APS mechanism: as shown in fig. 5, taking network 1 as an example, MC-APS in network 1 includes an operation PW between PE1 and PE3, a protection PW between PE2 and PE3, and a dual-node interconnection pseudowire (dual node interconnection PW, DNI-PW) between PE1 and PE 2. The MC-APS in network 1 detects the status of the working PW, protection PW and DNI-PW through an operations administration maintenance (operation administration and maintenance, OAM) mechanism. The working PW is used as a PW for transmitting messages in the network 1 and the network 2, the protection PW is a standby PW of the working PW, and the DNI-PW is used to implement cross-device state communication, so that switching actions at two ends of the PE1 and the PE2 are coordinated and consistent. Meanwhile, DNI-PW is also used to carry traffic (in some fault situations, the traffic after the dual homing protection is switched will be carried on DNI-PW).

MC-LAG mechanism: as shown in fig. 5, the MC-LAG in the network 1 includes an intra-device LAG deployed in the PE1 device (i.e., LAG1 between the PE1 device and the PE4 device), an intra-device LAG deployed in the PE2 device (i.e., LAG1 between the PE2 device and the PE5 device), and the MC-LAG between the PE1 device and the PE2 device. The PE1 device and the PE2 device perform cross-device synchronous communication through the MC-LAG, periodically mutually announce states of intra-device LAGs (LAG 1 and LAG 2) on the dual-homing node PE1 device and the PE2 device, and meanwhile, negotiates actions of two sides according to fault conditions.

Referring to fig. 6, fig. 6 is a schematic diagram of switching protection under the MC-APS mechanism and the MC-LAG mechanism. As shown in fig. 6, if the PE1 device itself fails, the service packet cannot be transmitted through the PE1 device, which will cause unavailability of PW between the PE3 device, the PE1 device, and the PE5 device, unavailability of PW between the PE4 device, the PE1 device, and the PE5 device, and unavailability of PW between the PE1 device and the PE2 device. Therefore, the switching of the PE6 equipment is triggered, and messages between the network 1 and the network 2 are transmitted by PW among the PE6 equipment, the PE2 equipment and the PE3 equipment and PW among the PE6 equipment, the PE2 equipment and the PE4 equipment; if the LAG between the PE1 device and the PE5 device fails (for example, a port corresponding to the LAG in the PE1 device fails, or a port corresponding to the LAG in the PE5 device fails), the PE1 device may still be used to transmit a packet, and the packet may be transmitted between the PW of the PE1 device and the PW of the PE2 device, so that the PE5 is triggered to switch the service to the PE6 device, the PW of the PE6 device, the PE2 device, the PW of the PE1 device and the PE3 device is used to transmit a packet between the network 1 and the network 2, and the PW of the PE6 device, the PE2 device, the PW of the PE1 device and the PE4 device is used to transmit a packet between the network 1 and the network 2.

Referring to fig. 7, fig. 7 is a schematic diagram of a fault scenario under the MC-APS mechanism and the MC-LAG mechanism. As shown in fig. 7, no failure occurs in the PE1 device itself, and messages can be communicated between the PE5 device and the PE1 device, while in fig. 7, the PW from the PE1 device to the PE3 fails, and the PW from the PE1 device to the PE2 fails, i.e. all PWs between the PE1 device and the PE3 fail. However, since the PE1 equipment does not have a fault, the message in the PE5 equipment can still be transmitted to the PE1 equipment, so that the PE5 equipment cannot sense the fault and cannot respond to the switching; on the other hand, since the PW of the PE1 device to the PE2 device has a failure, even if the PE1 device senses the failure, the PE2 device cannot be notified of the failure information to trigger switching.

In summary, when the communication link between the two networks of the working PE device group is normally reachable, but all PWs between a certain PE device in the PE device group and a Customer Edge (CE) device of the network where the PE device group is located are not reachable, the MC-APS mechanism and the MC-LAG mechanism cannot take effect on the failure, and then the message between the two networks cannot be transferred.

In view of the above, the present application provides a method for processing a message, which is used for solving PW faults of a network. The method for processing the message is applied to a two-Layer virtual private network (Layer 2Virtual Private Network,L2VPN), the L2VPN comprises a first network and a second network, the first network comprises a first PE device and a second PE device, the second network comprises a third PE device and a fourth PE device, and the second PE device is in communication connection with CE devices in the first network. The second PE device is used for communicating service flow with the CE device. Referring to fig. 8, fig. 8 is a flow chart of a message processing method according to an embodiment of the application, and as shown in fig. 8, the message processing method according to an embodiment of the application includes:

101. the first PE device determines that all PW between the first PE device and the second PE device have faults.

In the application, the first PE equipment does not have faults, and the first PE equipment and the third PE equipment can normally communicate with each other, namely, the message of the third PE equipment can be transmitted to the first PE equipment. However, as shown in fig. 8, all PWs between the first PE device and the second PE device have failed, so that the packet from the second PE device cannot reach the third PE device through forwarding of the first PE device, i.e. the third PE device cannot receive the packet from the second PE device. However, the third PE device cannot determine the reason why it cannot receive the message from the second PE device, either because a PW failure occurs or because the second PE device does not send a message to the third PE device at all; on the other hand, since the message of the third PE device may be normally transmitted to the first PE device, the third PE device may consider that the PW of the message transmission remains normal. In general, the third PE device cannot perceive that all PWs between the first PE device and the second PE device have failed, regardless of whether it is an upstream messaging service or a downstream messaging service.

All PWs between the first PE device and the second PE device refer to all PWs capable of performing packet interworking between the first PE device and the second PE device, including PWs directly connected to the first PE device and the second PE device (e.g., PWs established by PE1 device-PE 3 device shown in fig. 5), and segmented PWs bridged by other network devices between the first PE device and the second PE device (e.g., PWs established by PE1 device-PE 2 device-PE 3 device shown in fig. 5).

In some possible implementations, the first network further includes a fifth PE device, with an MC-LAG disposed between the first network and the second network, the MC-LAG including a first link aggregation group LAG between the first PE device and the third PE device, and a second LAG between the fifth PE device and the fourth PE device. The first LAG and the second LAG may be used for message transmission between the first network and the second network, where one LAG is used as a working LAG (for example, a LAG between the first PE device and the third PE device in the present application), the other LAG is used as an alternative LAG (for example, a LAG between the fifth PE device and the fourth PE device in the present application), and after the MC-LAG switching protection is triggered by the working LAG, the message between the first network and the second network is transmitted by the alternative LAG. Further, an MC-APS mechanism is deployed between the first PE device and the fifth PE device in the first network, that is, a dual-node interconnection pseudowire (dual node interconnection PW, DNI-PW) is established between the first PE device and the fifth PE device, and similarly, an MC-APS mechanism is deployed between the third PE device and the fourth PE device in the second network, that is, a DNI-PW is established between the third PE device and the fourth PE device, and after the MC-LAG switching protection is triggered, the first PE device and the fifth PE device perform a negotiation switching action through the DNI-PW, or the third PE device and the fourth PE device perform a negotiation switching action through the DNI-PW.

In the application, the first PE device periodically checks the connectivity of all PW between the first PE device and the second PE device, thereby determining whether each PW between the first PE device and the second PE device has faults. In some possible implementations, the first PE device may detect the PW based on an operation administration and maintenance (operation administration and maintenance, OAM) mechanism of the PW. By taking the first PE device as the host device and the second PE device as the source device as an example, when the host device cannot receive the detection message sent by the source device for 3 continuous periods, the connection state is considered to be Down, and then it can be determined that the PW between the host device and the source device has a fault, that is, the traffic flow between the host device and the source device cannot reach.

102. The first PE device sends out a fault indication.

In some possible embodiments, the first PE device sets down a link aggregation control (link aggregation control protocol, LACP) protocol corresponding to the first LAG, thereby making the first LAG unavailable. The third PE device at the other end of the first LAG may sense that the LACP protocol of the first LAG has been down, so that the third PE device triggers the protection switching mechanism of the MC-LAG.

In some possible embodiments, the first PE device turns off all ports corresponding to the first LAG established between the first PE device and the third PE device. In the application, turning off the port corresponding to the LAG means that the port corresponding to the LAG is forbidden to enable to send out the optical signal, the third PE device cannot receive the optical signal from the first PE device, and the third PE device triggers the protection switching mechanism of the MC-LAG.

In some possible embodiments, since the traffic flow can be exchanged between the first PE device and the third PE device normally, the first PE device may send a failure indication message to the second PE device, where the failure indication message includes first PW information, and the first PW information indicates that all pseudowires PW between the first PE device and the second PE device have failed. After the third PE device receives the fault indication message, the first PW information is obtained through analysis, so that the fault is determined, and a protection switching mechanism of the MC-LAG is triggered.

In some possible embodiments, since the first LAG is established between the first PE device and the third PE device, the fault indication packet may be carried in a link aggregation control protocol packet (Link Aggregation Control Protocol Data Unit, LACPDU) and transmitted through the first LAG.

It should be noted that, in the present application, the role of the fault indication is to trigger the third PE device to execute the switching action, and switch the message transmission service of the second network to the fourth PE device for transmission. Therefore, the specific content form of the fault indication sent by the first PE device is not specifically limited by the present application.

103. And the third PE device executes the switching action.

In the application, when a communication link between PE devices working between two networks is normally reachable, but all PWs between a network side PE device (namely PE device connected with PE devices in an opposite end network) and a user side PE device (namely PE device connected with CE devices in the network) in a certain network are unreachable, the network side PE device of the network can sense the fault and trigger the PE devices of the opposite end network to switch, thereby solving the PW fault of the network.

As can be seen from the above, the first network further includes a fifth PE device, and a second LAG is established between the fifth PE device and the fourth PE device, so that a message between the first network and the second network can be transferred through the second LAG, that is, the target link after switching in the present application includes the second LAG. And the fifth PE device and the second PE device belong to the first network, and the messages of the first network can be transmitted between the PW of the fifth PE device and the second PE device.

In some possible implementations, the first PE device continues to periodically detect PWs between the first PE device and the second PE device through the OAM mechanism even though all PWs between the first PE device and the second PE device have failed. When the first PE device detects that the fault of at least one PW between the first PE device and the second PE device is recovered, the first PE device sends out a fault recovery instruction, after the third PE device receives the fault recovery instruction, the protection switching mechanism is triggered again, the fourth PE device switches the message transmission service to the third PE device again, namely, the service flow between the first network and the second network is transmitted through a first path (namely, a link between the third PE device and the first PE device), and the recovered PW between the first PE device and the second PE device is transmitted.

Specifically, in some possible embodiments, in response to at least one PW recovery between the first PE device and the second PE device, the first PE device may take the LACP protocol corresponding to the first LAG as a revocation device (i.e., set UP the LACP protocol), as the third PE device at the other end of the first LAG, so that it may be perceived that the LACP protocol state of the first LAG has been revoked (i.e., set UP), and the third PE device triggers the protection switching mechanism of the MC-LAG.

In some possible embodiments, in response to the recovery of the fault of at least one PW between the first PE device and the second PE device, the first PE device opens all ports corresponding to the first LAG, that is, the first PE device enables the ports corresponding to the first LAG to emit light, the third PE device may receive the optical signal from the first PE device, and the third PE device triggers the protection switching mechanism of the MC-LAG.

In some possible embodiments, since the traffic flow may be exchanged between the first PE device and the third PE device normally, when the failure of at least one PW between the first PE device and the second PE device has been recovered, the first PE device may send a failure recovery indication to the second PE device, where the failure recovery indication includes second PW information, and the second PW information indicates that the failure of at least one PW has been recovered, so as to notify the third PE device to perform protection switching. After receiving the fault recovery instruction, the third PE device analyzes the fault recovery instruction to obtain second PW information, so that it is determined that at least one PW fault is recovered, and a protection switching mechanism of the MC-LAG is triggered.

In some possible embodiments, since the first LAG is established between the first PE device and the third PE device, the recovery indication packet may be carried in the LACPDU and transmitted through the first LAG.

In some possible embodiments, the restoration instruction packet is used to indicate that at least one PW between the first PE device and the second PE device has been restored.

In the application, the first PE device can continuously detect the connectivity of the PW between the first PE device and the second PE device so as to continuously work after the failed PW is recovered, thereby improving the solving efficiency of PW failure.

Referring to fig. 9, fig. 9 is a schematic diagram of a link switching scenario in an embodiment of the present application, as shown in fig. 9, a PE3 device sends a service flow to a PE2 device, but a PW in a network fails to simultaneously fail 1 and fail 2, so that a message from the PE2 device to the PE1 device is not reachable, and the service is interrupted. By the message processing method, when the PE2 device detects that all PW leading to the PE1 device is disconnected, the member LAG of the MC-LAG between the PE2 device and the PE3 device is set to DOWN. After the PE3 device detects that the member LAG is Down, the PE3 device triggers the service to switch to the PE5 device and then sends the service to the PE4 device, and the service flow of the network resumes the communication.

In order to better implement the above-described aspects of the embodiments of the present application, the following provides related devices for implementing the above-described aspects. Specifically, referring to fig. 10, fig. 10 is a schematic structural diagram of a network device, provided by an embodiment of the present application, used as a first provider edge PE device, applied to a two-layer virtual private network L2VPN, where the L2VPN includes a first network and a second network, the first network includes a first PE device and a second PE device, the second network includes a third PE device and a fourth PE device, and the second PE device is in communication connection with a customer edge CE device in the first network, where the network device includes:

a determining unit 201, configured to determine that all pseudowires PW between the first PE device and the second PE device have faults;

the processing unit 202 is configured to send out a fault indication, where the fault indication is configured to instruct the third PE device to switch traffic of the CE device from the first path to the second path, and the first path includes a link between the third PE device and the first PE device, and the second path includes a link between the third PE device and the fourth PE device and a target link between the fourth PE device and the second PE device.

In a specific embodiment, the first network further includes a fifth PE device, a cross-device link aggregation group MC-LAG is disposed between the first network and the second network, the MC-LAG includes a first link aggregation group LAG between the first PE device and the third PE device, and a second LAG between the fifth PE device and the fourth PE device, and the target link includes the second LAG.

In a specific embodiment, the processing unit 202 is specifically configured to: and setting down the link aggregation control LACP protocol corresponding to the first LAG.

In a specific embodiment, the processing unit 202 is specifically configured to: and all ports corresponding to the first LAG are turned off.

In a specific embodiment, the processing unit 202 is specifically configured to: and sending a fault indication message to the second PE equipment, wherein the fault indication message comprises first PW information, and the first PW information indicates that all pseudo wires PW between the first PE equipment and the second PE equipment have faults.

In a specific embodiment, the processing unit 202 is further configured to, when at least one PW between the first PE device and the second PE device fails to recover, send a failure recovery instruction by the first PE device, where the failure recovery instruction is used to instruct the third PE device to transmit traffic through the first path.

In a specific embodiment, the processing unit 202 is specifically configured to: and setting the LACP protocol corresponding to the first LAG up.

In a specific embodiment, the processing unit 202 is specifically configured to: and opening all ports corresponding to the first LAG.

In one possible design, the processing unit 202 is specifically configured to: and sending a fault recovery instruction to the second PE equipment, wherein the fault recovery instruction comprises second PW information, and the second PW information indicates that at least one PW has recovered from the fault.

It should be noted that, content such as information interaction and execution process between each module/unit in the network device, the method embodiment corresponding to fig. 8 in the present application is based on the same concept, and specific content may be referred to the description in the foregoing method embodiment of the present application, which is not repeated herein.

Referring to fig. 11, fig. 11 is a schematic structural diagram of a network device according to an embodiment of the present application, where a first PE device described in the corresponding embodiment of fig. 10 may be disposed on a network device 300, so as to implement the corresponding embodiment of fig. 8, and specifically, the network device 300 may have relatively large differences due to different configurations or performances, and may include one or more central processing units (central processing units, CPU) 322 (for example, one or more processors) and a memory 332, and one or more storage media 330 (for example, one or more mass storage devices) storing application programs 342 or data 344. Wherein the memory 332 and the storage medium 330 may be transitory or persistent. The program stored on the storage medium 330 may include one or more modules (not shown), each of which may include a series of instruction operations in the network device. Still further, the central processor 322 may be configured to communicate with the storage medium 330 to execute a series of instruction operations in the storage medium 330 on the network device 300.

The network device 300 may also include one or more power supplies 326, one or more wired or wireless network interfaces 350, one or more input/output interfaces 358, and/or one or more operating systems 341, such as Windows Server ^TM ，Mac OS X ^TM ，Unix ^TM ，Linux ^TM ，FreeBSD ^TM Etc.

It should be noted that, based on the same concept, the content of information interaction and execution process between each module/unit in the network device, which corresponds to the method embodiment of fig. 8 in the present application, the specific content may be referred to the description in the foregoing method embodiment of the present application, and the description is omitted herein.

Embodiments of the present application also provide a computer program product comprising a program product which, when run on a computer, causes the computer to perform a method as described in the embodiment shown in fig. 8.

There is also provided in an embodiment of the present application a computer-readable storage medium having stored therein a program for performing signal processing, which when run on a computer, causes the computer to perform the method as described in the embodiment shown in fig. 8.

The functions of the network device provided by the embodiment of the application can be integrated into a chip, and the chip comprises: a processing unit, which may be, for example, a processing circuit, and a communication unit, which may be, for example, an input/output interface, a pin or a circuit, etc. The processing unit may execute the computer-executable instructions stored in the storage unit to cause the chip to perform the method described in the embodiment shown in fig. 8. Optionally, the storage unit is a storage unit in the chip, such as a register, a cache, etc., and the storage unit may also be a storage unit in the wireless access device side located outside the chip, such as a read-only memory (ROM) or other type of static storage device that may store static information and instructions, a random access memory (random access memory, RAM), etc.

It should be further noted that the above described embodiments of the apparatus are only schematic, where the units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the embodiment of the device provided by the application, the connection relation between the modules represents that the modules have communication connection, and can be specifically implemented as one or more communication buses or signal lines.

From the above description of the embodiments, it will be apparent to those skilled in the art that the present application may be implemented by means of software plus necessary general purpose hardware, or of course by means of special purpose hardware including application specific integrated circuits, special purpose CPUs, special purpose memories, special purpose components, etc. Generally, functions performed by computer programs can be easily implemented by corresponding hardware, and specific hardware structures for implementing the same functions can be varied, such as analog circuits, digital circuits, or dedicated circuits. However, a software program implementation is a preferred embodiment for many more of the cases of the present application. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a readable storage medium, such as a floppy disk, a usb disk, a removable hard disk, a ROM, a RAM, a magnetic disk or an optical disk of a computer, etc., comprising several instructions for causing a computer device (which may be a personal computer, a training device, a network device, etc.) to perform the method according to the embodiments of the present application.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product.

The computer program product includes one or more computer instructions. When loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center via a wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be stored by a computer or a data storage device such as a training device, a data center, or the like that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy Disk, a hard Disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a Solid State Disk (SSD)), or the like.

Claims

1. The method for processing the message is characterized in that the method is applied to a two-layer virtual private network (L2 VPN), the L2VPN comprises a first network and a second network, the first network comprises a first operator edge PE device and a second PE device, the second network comprises a third PE device and a fourth PE device, and the second PE device is in communication connection with a user edge CE device, and the method comprises:

the first PE device determines that all pseudo wires PW between the first PE device and the second PE device have faults;

the first PE device sends out a fault indication, and the fault indication is used for indicating the third PE device to switch the service flow of the CE device from a first path to a second path, wherein the first path comprises a link between the third PE device and the first PE device, and the second path comprises a link between the third PE device and the fourth PE device and a target link between the fourth PE device and the second PE device.

2. The method of claim 1, wherein the first network further comprises a fifth PE device, wherein a cross-device link aggregation group MC-LAG is disposed between the first network and the second network, wherein the MC-LAG comprises a first link aggregation group LAG between the first PE device and the third PE device, and wherein the target link comprises a second LAG between the fifth PE device and the fourth PE device.

3. The method of claim 2, wherein the first PE device issues a failure indication comprising:

and the first PE device sets down a link aggregation control LACP protocol corresponding to the first LAG.

4. The method of claim 2, wherein the first PE device issues a failure indication comprising:

and the first PE equipment turns off all ports corresponding to the first LAG.

5. The method according to claim 1 or 2, wherein the first PE device issues a failure indication, comprising:

the first PE device sends a fault indication message to the second PE device, wherein the fault indication message comprises first PW information, and the first PW information indicates that all pseudo wires PW between the first PE device and the second PE device have faults.

6. The method of any one of claims 1 to 5, further comprising:

and responding to at least one PW fault recovery between the first PE equipment and the second PE equipment, wherein the first PE equipment sends out a fault recovery instruction, and the fault recovery instruction is used for instructing the third PE equipment to transmit the service flow through the first path.

7. The method of claim 6, wherein the first PE device issues a failure recovery indication comprising:

and the first PE equipment sets up an LACP protocol corresponding to the first LAG.

8. The method of claim 6, wherein the first PE device issues a resume indication comprising:

and the first PE equipment starts all ports corresponding to the first LAG.

9. The method of claim 6, wherein the first PE device issues a failure recovery indication comprising:

the first PE device sends a fault recovery instruction to the second PE device, wherein the fault recovery instruction comprises second PW information, and the second PW information indicates that the at least one PW fault is recovered.

10. A communication system, wherein the communication system is applied to a two-layer virtual private network L2VPN, the communication system includes a first operator edge PE device and a second PE device in a first network, and a third PE device and a fourth PE device in the second network, the second PE device is communicatively connected to a user edge CE device, the first PE device is configured to determine that all pseudowires PW between the first PE device and the second PE device are faulty, and send a fault indication, where the fault indication is configured to instruct the third PE device to switch traffic of the CE device from a first path to a second path, where the first path includes a link between the third PE device and the first PE device, and the second path includes a link between the third PE device and the fourth PE device and a target link between the fourth PE device and the second PE device;

And the third PE device is used for switching the service flow from the first path to the second path according to the fault information.

11. The communication system of claim 10, wherein the first network further comprises a fifth PE device, wherein a cross-device link aggregation group MC-LAG is disposed between the first network and the second network, wherein the MC-LAG comprises a first link aggregation group LAG between the first PE device and the third PE device, and wherein the target link comprises a second LAG between the fifth PE device and the fourth PE device.

12. The communication system according to claim 11, wherein when the first PE device issues a failure indication, the method is specifically configured to:

and setting down the link aggregation control LACP protocol corresponding to the first LAG.

13. The communication system according to claim 11, wherein when the first PE device issues a failure indication, the method is specifically configured to:

and all ports corresponding to the first LAG are turned off.

14. The communication system according to claim 10 or 11, wherein when the first PE device issues a failure indication, the communication system is specifically configured to:

And sending a fault indication message to the second PE equipment, wherein the fault indication message comprises first PW information, and the first PW information indicates that all pseudo wires PW between the first PE equipment and the second PE equipment have faults.

15. The communication system according to any one of claims 10 to 14, wherein the first PE device is further configured to:

when at least one PW between the first PE device and the second PE device is recovered, the first PE device sends out a fault recovery instruction, and the fault recovery instruction is used for instructing the third PE device to transmit the service flow through the first path.

16. The communication system according to claim 15, wherein when the first PE device issues a recovery instruction, the method is specifically configured to:

and setting the LACP protocol corresponding to the first LAG to up.

17. The communication system according to claim 15, wherein when the first PE device issues a recovery instruction, the method is specifically configured to:

and opening all ports corresponding to the first LAG.

18. The communication system according to claim 15, wherein when the first PE device issues a failure recovery instruction, the method is specifically configured to:

And sending a fault recovery instruction to the second PE equipment, wherein the fault recovery instruction comprises second PW information, and the second PW information indicates that the at least one PW fault is recovered.

19. A network device for use as a first operator edge PE device, wherein the network device is applied to a two-layer virtual private network, L2VPN, the L2VPN comprising a first network and a second network, the first network comprising the first PE device and the second PE device, the second network comprising a third PE device and a fourth PE device, wherein the second PE device is communicatively connected to a customer edge CE device in the first network, the network device comprising:

a determining unit, configured to determine that all pseudowires PW between the first PE device and the second PE device have a fault;

the processing unit is used for sending out fault indication, wherein the fault indication is used for indicating the third PE device to switch the service flow of the CE device from a first path to a second path, the first path comprises a link between the third PE device and the first PE device, and the second path comprises a link between the third PE device and the fourth PE device and a target link between the fourth PE device and the second PE device.

20. The network device of claim 19, wherein the first network further comprises a fifth PE device, wherein a cross-device link aggregation group MC-LAG is disposed between the first network and the second network, wherein the MC-LAG comprises a first link aggregation group LAG between the first PE device and the third PE device, and wherein a second LAG between the fifth PE device and the fourth PE device, wherein the target link comprises the second LAG.

21. The network device of claim 20, wherein the processing unit is specifically configured to:

22. The network device of claim 20, wherein the processing unit is specifically configured to:

and all ports corresponding to the first LAG are turned off.

23. The network device according to claim 19 or 20, wherein the processing unit is specifically configured to:

24. The network device according to any one of claim 19 to 23,

the processing unit is further configured to, when at least one PW between the first PE device and the second PE device is recovered, send a fault recovery instruction by the first PE device, where the fault recovery instruction is used to instruct the third PE device to transmit the traffic through the first path.

25. The network device of claim 24, wherein the processing unit is specifically configured to:

and setting the LACP protocol corresponding to the first LAG to up.

26. The network device of claim 24, wherein the processing unit is specifically configured to:

and opening all ports corresponding to the first LAG.

27. The network device of claim 24, wherein the processing unit is specifically configured to:

28. A network device, for use as a first carrier edge PE device, wherein the network device is configured for use in a two-layer virtual private network, L2VPN, the L2VPN comprising a first network and a second network, the first network comprising the first PE device and the second PE device, the second network comprising a third PE device and a fourth PE device, the second PE device communicatively coupled to a customer edge CE device in the first network, the network device comprising:

A memory for storing a program;

a processor coupled to the memory for executing the program in the memory to cause the network device to perform the method of any of claims 1 to 9.

29. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program which, when executed by a processor, implements the method according to any one of claims 1 to 9.

30. A computer program product having computer readable instructions stored therein, which when executed by a processor, implement the method of any of claims 1 to 9.