CN111404813B

CN111404813B - Communication method and device

Info

Publication number: CN111404813B
Application number: CN202010220206.0A
Authority: CN
Inventors: 邢家茂
Original assignee: New H3C Security Technologies Co Ltd
Current assignee: New H3C Security Technologies Co Ltd
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2022-04-01
Anticipated expiration: 2040-03-25
Also published as: CN111404813A

Abstract

The application provides a communication method and a device, which are applied to a main service Provider Edge (PE) device in a two-layer virtual private network (L2 VPN), wherein the L2VPN also comprises a slave PE device, a Bypass virtual link Bypass (Bypass) PW is configured between the main PE device and the slave PE device, and the method comprises the following steps: when determining that any main link fails, the main PE equipment acquires a prestored bidirectional association relationship between main link table entries and a Bypass PW table entry; establishing a bidirectional association relation between a main link table entry except the failed main link and a Bypass PW table entry, and forwarding the received service data by using the established bidirectional association relation; and sending a path switching instruction to the slave PE equipment, so that the slave PE equipment establishes a bidirectional association relationship between a standby link table entry of the failed main link and a Bypass PW table entry, and forwards the service data by using the established bidirectional association relationship between the standby link table entry and the Bypass PW table entry. Therefore, the link is switched rapidly, and the forwarding chip in the PE equipment does not need to be operated frequently.

Description

Communication method and device

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communication method and apparatus.

Background

With the continuous development of networks, the reliability of networking is more and more important. Generally, a virtual link (PW) redundancy technique may be utilized to improve the reliability of the network. In an existing two-Layer Virtual Private Network (L2 VPN), a first Customer Edge (CE) device, a second customer Edge device, a first Provider Edge (PE) device, a second Provider Edge device, and a third Provider Edge device are included, where the second PE device and the third PE device are each a master device and a standby device, a Bypass Virtual link (Bypass PW) is configured between the second PE device and the third PE device, and when the second PE device is a master PE device, the first CE device may sequentially perform service traffic with the first PE device, the second PE device, and the second CE device, where a link between the first PE device and the second PE device may be referred to as a PW link, and a link between the second CE device and the second PE device may be referred to as an AC link. When the PW link or the AC link fails, the traffic between the first CE equipment and the second CE equipment can be realized through the Bypass PW.

However, in the prior art, when a PW link fails or an AC link fails, when performing Bypass PW switching, a manner of deleting and then adding is adopted, and the entry is stored in a forwarding chip of the PE device. When the primary PW fails, the primary PW table entry in the forwarding chip is deleted, and then the primary AC table entry and the Bypass PW table entry are associated and added into the forwarding chip. When the main AC fails, the main AC table entry in the forwarding chip is deleted, and then the main PW table entry and the Bypass PW table entry are associated and added into the forwarding chip, that is, when a link is to be switched each time a failure occurs, the Bypass PW is activated and then can be issued to the forwarding chip, so that hardware table entries in the forwarding chip are frequently operated, time is consumed, and the PW protection switching performance is influenced.

Therefore, how to quickly restore the communication link between CE devices upon PW link failure or AC link failure, and reducing frequent operations on the forwarding chip is one of considerable issues.

Disclosure of Invention

In view of this, the present application provides a communication method and apparatus, which are used to quickly recover a communication link between CE devices when an active link fails, and reduce frequent operations on a forwarding chip.

Specifically, the method is realized through the following technical scheme:

according to a first aspect of the present application, a communication method is provided, where the communication method is applied to a primary provider edge PE device in a L2VPN of a two-layer virtual private network, the L2VPN further includes a secondary provider edge PE device, where a Bypass virtual link Bypass PW is configured between the primary PE device and the secondary PE device, and the method includes:

when determining that any main link fails, the main PE equipment acquires a prestored bidirectional association relationship between main link table entries and a Bypass PW table entry;

establishing a bidirectional association relation between a main link table entry except the failed main link and a Bypass PW table entry, and forwarding the received service data by using the established bidirectional association relation;

and sending a path switching instruction to the slave PE equipment so that the slave PE equipment establishes a bidirectional association relationship between a standby link table entry of the failed main link and a Bypass PW table entry, and forwards service data by using the established bidirectional association relationship between the standby link table entry and the Bypass PW table entry.

According to a second aspect of the present application, there is provided a communication method applied to a secondary provider edge PE device in a L2VPN of a two-layer virtual private network, the L2VPN further includes a primary provider edge PE device, wherein a Bypass virtual link Bypass PW is configured between the primary PE device and the secondary PE device, and the method includes:

receiving a path switching instruction sent by the main PE equipment from the auxiliary PE equipment, and acquiring a prestored bidirectional association relation between standby link table items and a Bypass PW table item, wherein the path switching instruction is sent by the main PE equipment when any main link is determined to be in failure;

establishing a bidirectional association relation between a standby link table entry of the failed main link and a Bypass PW table entry, and forwarding service data by using the established bidirectional association relation between the standby link table entry and the Bypass PW table entry.

According to a third aspect of the present application, there is provided a communication apparatus, which is disposed in a primary provider edge PE device in a layer two virtual private network L2VPN, where the L2VPN further includes a secondary provider edge PE device, and a Bypass virtual link Bypass PW is configured between the primary PE device and the secondary PE device, and the apparatus includes:

the acquisition module is used for acquiring a prestored bidirectional association relation between main link table entries and a Bypass PW table entry when any main link is determined to be in fault;

the incidence relation establishing module is used for establishing a bidirectional incidence relation between the table entry of the main link except the failed main link and the Bypass PW table entry;

the forwarding module is used for forwarding the received service data by utilizing the established bidirectional association relation;

a sending module, configured to send a path switching indication to the slave PE device, so that the slave PE device establishes a bidirectional association relationship between a standby link table entry of a failed main link and a Bypass PW table entry, and forwards service data by using the established bidirectional association relationship between the standby link table entry and the Bypass PW table entry.

According to a fourth aspect of the present application, there is provided a communication apparatus, configured in a secondary provider edge PE device in a L2VPN, the L2VPN further includes a primary provider edge PE device, wherein a Bypass virtual link Bypass PW is configured between the primary PE device and the secondary PE device, and the apparatus includes:

a receiving module, configured to receive a path switching indication sent by the primary PE device, and obtain a prestored bidirectional association relationship between standby link table entries and a Bypass PW table entry, where the path switching indication is sent by the primary PE device when determining that any primary link fails;

the incidence relation establishing module is used for establishing a bidirectional incidence relation between a standby link table item of the main link with the fault and a Bypass PW table item;

and the forwarding module is used for forwarding the service data by utilizing the established bidirectional association relationship between the standby link table entry and the Bypass PW table entry.

According to a fifth aspect of the present application, there is provided a provider edge PE device, comprising a processor and a machine-readable storage medium, the machine-readable storage medium storing machine-executable instructions capable of being executed by the processor, the processor being caused by the machine-executable instructions to perform the method provided by the first or second aspect of the embodiments of the present application.

According to a sixth aspect of the present application, there is provided a machine-readable storage medium storing machine-executable instructions that, when invoked and executed by a processor, cause the processor to perform the method provided by the first or second aspect of the embodiments of the present application.

The beneficial effects of the embodiment of the application are as follows:

the communication method and apparatus provided in the embodiment of the present application store the bidirectional association relationship between the entries of the primary links and the Bypass PW entries in the forwarding chip of the PE device in advance, so that when the primary PE device determines that any primary link fails, the bidirectional association relationship and the Bypass PW entries are directly read, then the bidirectional association relationship between the primary link entry of the primary link and the Bypass PW entry of the non-failed primary link is re-established, then the service data is forwarded based on the newly established bidirectional association relationship, and in addition, the secondary PE device also needs to establish the bidirectional association relationship between the standby link entry of the failed primary link and the Bypass PW entry, so that the secondary PE device forwards the service data using the newly established bidirectional association relationship, thereby not only realizing the fast switching of paths and the normal forwarding of the service data, but also because the bidirectional association relationship and the Bypass PW entries are stored in the forwarding chip in advance, the forwarding chip of the PE equipment does not need to be frequently operated, so that the pressure of the forwarding chip in the PE equipment is reduced, and meanwhile, the link switching time is also saved.

Drawings

Fig. 1 is a schematic diagram of a layer two virtual private network L2VPN networking according to an exemplary embodiment of the present application;

FIG. 2 is a block diagram of a facilitator edge facility 200, according to an exemplary embodiment of the present disclosure;

FIG. 3 is an interaction flow diagram illustrating a method of communication according to an exemplary embodiment of the present application;

fig. 4a is a schematic diagram illustrating a bidirectional association relationship and a reference of a Bypass PW entry in a single Bypass PW scene according to an exemplary embodiment of the present application;

fig. 4b is a reference schematic diagram of a bidirectional association relationship established when a primary PW link fails in a single Bypass PW scene according to an exemplary embodiment of the present application;

fig. 4c is a reference schematic diagram of a bidirectional association relationship established when a primary AC link fails in a single Bypass PW scene according to an exemplary embodiment of the present application;

fig. 5a is a schematic data flow diagram illustrating a single Bypass PW scenario in which an active link does not fail according to an exemplary embodiment of the present application;

fig. 5b is a schematic diagram illustrating a data flow when a link of an active PW fails in a single Bypass PW scene according to an exemplary embodiment of the present application;

fig. 5c is a schematic diagram illustrating a data flow when a primary AC link fails in a single Bypass PW scenario according to an exemplary embodiment of the present application;

fig. 6a is a schematic diagram illustrating a bidirectional association relationship and a reference of a Bypass PW entry in a dual Bypass PW scene according to an exemplary embodiment of the present application;

fig. 6b is a reference schematic diagram of a bidirectional association relationship established when a primary PW link fails in a dual Bypass PW scene according to an exemplary embodiment of the present application;

fig. 6c is a reference schematic diagram of a bidirectional association relationship established when a primary AC link fails in a dual Bypass PW scenario according to an exemplary embodiment of the present application;

fig. 7a is a schematic data flow diagram illustrating a situation where an active link has no failure in a dual Bypass PW scenario according to an exemplary embodiment of the present application;

fig. 7b is a schematic diagram illustrating a data flow when a link of an active PW fails in a dual Bypass PW scenario according to an exemplary embodiment of the present application;

fig. 7c is a schematic diagram of a data flow when a primary AC link fails in a dual Bypass PW scenario according to an exemplary embodiment of the present application;

FIG. 8 is a flow chart diagram illustrating another method of communication according to an exemplary embodiment of the present application;

FIG. 9 is a flow chart diagram illustrating yet another method of communication according to an exemplary embodiment of the present application;

FIG. 10 is a block diagram of a communication device shown in an exemplary embodiment of the present application;

FIG. 11 is a block diagram of another communication device shown in an exemplary embodiment of the present application;

fig. 12 is a block diagram illustrating a provider edge PE device according to an exemplary embodiment of the present application.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the corresponding listed items.

It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.

In the embodiment of the present application, a failed link or a temporarily unassociated link is schematically shown by a dotted line in the drawing, and an available link is shown by a solid line, for example, referring to fig. 4b, when an active PW link fails, an active PW link entry is schematically shown by a dotted line, and an association relationship between the active PW link entry and an active AC link entry is also shown by a dotted line, which indicates that communication service cannot be provided, and the like.

Referring to fig. 1, a L2VPN networking in a layer two virtual private network provided in an embodiment of the present application includes two selectable transmission links, a primary link and a standby link, where a first CE device may perform inter-service communication with a second CE device through the primary link or the standby link. The active link is a link established between the primary PE device and the first CE device, and the second CE device, and the standby link is a link established between the secondary PE device and the first CE device, and the second CE device. Moreover, at least one Bypass PW pseudo wire is configured between the main PE equipment and the slave PE equipment, and when the main PE equipment determines that any corresponding main link of the main PE equipment fails, the prestored bidirectional association relationship between main link table entries and Bypass PW table entries are obtained; establishing a bidirectional association relation between a main link table entry except the failed main link and a Bypass PW table entry, and forwarding the received service data by using the established bidirectional association relation; meanwhile, a path switching instruction is sent to the slave PE equipment, so that the slave PE equipment establishes a bidirectional association relationship between a standby link table entry of the failed main link and a Bypass PW table entry, and forwards service data by the established bidirectional association relationship between the standby link table entry and the Bypass PW table entry. Because the forwarding chip of the PE device stores the bidirectional association relationship between the items of the main link and the Bypass PW table in advance, when the main link fails, the bidirectional association relationship between the items of the main link except the failed main link and the Bypass PW table can be established in time based on the pre-stored table, so that the forwarding of the service data can be realized based on the established bidirectional association relationship, namely, the communication link between the CE devices can be quickly recovered, and meanwhile, the forwarding chip in the PE device does not need to be operated frequently, thereby solving the problem of larger hardware development caused by frequently operating the forwarding chip in the prior art.

It should be noted that one active link may carry multiple active AC links and multiple active PW links, that is, multiple active PW links may be established between the first PE device and the active PE device, and multiple active AC links may be established between the active PE device and the second CE device, so that there is a corresponding relationship between the active AC links and the active PW links, so that a set of corresponding active PW links and active AC links may be used to transmit one type of service data.

Accordingly, one standby link can carry multiple standby AC links and multiple standby PW links, that is, multiple standby PW links can be established between the first PE device and the slave PE device, and multiple standby AC links can be established between the slave PE device and the second CE device, so that there is a corresponding relationship between the standby AC links and the standby PW links, so that a set of corresponding standby PW links and standby AC links can be used to transmit one type of service data.

Fig. 2 is a schematic structural diagram of a provider edge device 200. The provider edge device 200 includes a memory 210, a processor 220, and a communication module 230. The memory 210, the processor 220, and the communication module 230 are electrically connected to each other directly or indirectly to realize data transmission or interaction. For example, the components may be electrically connected to each other via one or more communication buses or signal lines.

The memory 210 is used for storing programs or data. The Memory 210 may be, but is not limited to, a Random Access Memory (RAM), a Read Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable Read-Only Memory (EPROM), an electrically Erasable Read-Only Memory (EEPROM), and the like.

The processor 220 is used to read/write data or programs stored in the memory 210 and perform corresponding functions.

The communication module 230 is configured to establish a communication connection between the provider edge device 200 and another communication terminal through the network, and to receive and transmit data through the network, where taking the provider edge device 200 as a primary PE device as an example for description, the primary PE device may utilize the communication module 230 therein to communicate with the first PE device or the second CE device through the network.

It should be understood that the configuration shown in FIG. 2 is merely a schematic diagram of the configuration of the facilitator edge device 200, and that the facilitator edge device 200 may include more or fewer components than shown in FIG. 2, or have a different configuration than shown in FIG. 2. The components shown in fig. 2 may be implemented in hardware, software, or a combination thereof. The provider edge device 200 may be a master PE device and/or a slave PE device in fig. 1.

The following describes the communication method provided in the embodiments of the present application in detail.

Referring to fig. 3, an interaction flow diagram of a communication method provided in this embodiment of the present application is shown, where the method may be applied to a master PE device and a slave PE device, and an interaction flow of the master PE device and the slave PE device implementing the communication method may be implemented according to the following processes:

s301, when determining that any one main link fails, the main PE device acquires a prestored bidirectional association relationship between main link table entries and a Bypass PW table entry.

In specific implementation, the present embodiment issues the bidirectional association relationship between the entries of the main link and the Bypass virtual link Bypass PW entry to the forwarding chip of the main PE device in advance, so that when the main PE device determines that the main link where the main PE device is located has a fault, the main PE device can directly obtain the bidirectional association relationship and Bypass PW entry from the forwarding chip of the main PE device. Compared with the prior art, the forwarding chip is not required to be operated for many times.

It should be noted that the pre-stored bidirectional association relationship between the primary links is used to implement data interaction when the primary links are not failed, that is, as described with reference to fig. 1, in a case that the primary links are normal, when the first CE device interacts with the second CE device, the first CE device first sends the service data to the first PE device, then the first PE device forwards the service data to the primary PE device through the primary link between the first PE device and the primary PE device, and finally the primary PE device sends the service data to the second CE device through the primary link between the primary PE device and the second CE device, thereby implementing sending of the service data, and similarly, when the second CE device replies reply data to the first CE device, since the association relationship established by the primary PE device is bidirectional, the second CE device can implement reverse transmission from the primary PE device, the first PE device to the first CE device, and further realizing the business transaction between the first CE equipment and the second CE equipment.

S302, the main PE device establishes a bidirectional association relation between the main link table entry except the failed main link and the Bypass PW table entry, and forwards the received service data by using the established bidirectional association relation.

In this step, because the primary links of the primary PE devices fail, that is, the bidirectional association relationship between the primary link table entries formed between the primary links cannot be used, the communication between the first CE device and the second CE device is interrupted. Therefore, in order to quickly implement the path switching, in this embodiment, after the bidirectional association relationship and the Bypass PW table entry are obtained in step S301, the bidirectional association relationship between the primary link table entry and the Bypass PW table entry except for the failed primary link is established, so that the primary PE device can use the non-failed primary link table entry and the Bypass PW table entry to implement the communication between the first CE device and the second CE device, that is, the primary PE device transmits service data to the Bypass PW virtual link based on the non-failed primary link, and then transmits the service data to the secondary PE device through the Bypass PW virtual link; or, the slave PE device transmits the service data to the master PE device through the Bypass PW virtual link, and then the master PE device transmits the service data to the outside through the failure-free master link.

S303, the master PE device sends a path switching instruction to the slave PE device.

Specifically, since the Bypass PW is a communication link between the master PE device and the slave PE device, and needs the slave PE device to participate in communication between the first CE device and the second CE device, the master PE device sends a path switching instruction to the slave PE device to notify that the slave PE device starts to operate, and to notify the slave PE device of link information of the failed master link.

S304, after receiving the path switching instruction sent by the main PE device, the slave PE device obtains the prestored bidirectional association relationship between the standby link table items and the Bypass PW table item.

In this step, in order to implement fast switching of the link, the slave forwarding chip of the PE device also prestores the bidirectional association relationship between the standby link table entries and the Bypass PW table entry, so that the slave PE device also obtains the bidirectional association relationship and the Bypass PW table entry from the forwarding chip of the PE device after receiving the link switching instruction.

S305, establishing a bidirectional association relation between a standby link table item of a failed main link and a Bypass PW table item from the PE equipment;

s306, the slave PE equipment forwards the service data by using the established bidirectional association relationship between the standby link table entry and the Bypass PW table entry.

In this step, after implementing step S304, the slave PE device may establish a bidirectional association relationship between a backup link table entry of the backup link of the failed active link and the Bypass PW table entry, so that the slave PE device may send the service data received by the Bypass PW virtual link to the backup link of the bidirectional association relationship, and send the service data to the outside through the backup link, thereby reaching the first CE device or the second CE device. By implementing the flow shown in fig. 3, not only is it unnecessary to frequently operate the forwarding chip of the PE device, but also a fast switching of the path is achieved, and meanwhile, a smooth communication between the first CE device and the second CE device is achieved.

Optionally, in this embodiment of the present application, the primary link of the primary PE device includes a primary PW link and a primary AC link; specifically, referring to fig. 1, the active PW link refers to a link established between the first PE device and the primary PE device, and is also referred to as a PW side link, and the active AC link refers to a link established between the primary PE device and the second CE device, and is also referred to as an AC side link. Correspondingly, the bidirectional association relationship between the primary PW link entry and the primary AC link entry stored in the primary PE device is the bidirectional association relationship between the primary PW link entry and the primary AC link entry.

On this basis, in step S301, the pre-stored bidirectional association relationship between the primary link table entry includes a bidirectional association relationship between the primary PW link table entry and the primary AC link table entry, and on this basis, the step S302 establishes a bidirectional association relationship between the primary link table entry and the Bypass PW table entry except for the failed primary link, including:

if the main PW link fails, establishing a bidirectional association relation between the main AC link table entry and the Bypass PW table entry;

if the main AC link fails, establishing a bidirectional association relation between the main PW link table entry and the Bypass PW table entry.

In specific implementation, when the primary PW link fails, that is, when a link between the first PE device and the primary PE device in fig. 1 fails, in order to implement a service transaction between the first CE device and the second CE device, the primary PE device needs to modify the bidirectional association relationship stored in the forwarding chip therein to a bidirectional association relationship between the primary AC link entry of the primary AC link and the Bypass PW entry, so as to establish communication between the primary AC link and the Bypass PW virtual link. And then, combining the communication connection between the standby link of the fault main PW link established by the slave PE equipment and the Bypass PW virtual link, so that the communication between the first CE equipment and the second CE equipment can be realized.

Similarly, when the primary AC link fails, that is, a link between the second CE device and the primary PE device in fig. 1 fails, at this time, in order to enable a service transaction between the first CE device and the second CE device, the primary PE device needs to modify the bidirectional association relationship into the bidirectional association relationship between the primary PW link entry and the Bypass PW entry, so that communication between the primary PW link and the Bypass PW virtual link is established, and then, the communication connection between the standby link of the failed primary AC link and the Bypass PW virtual link, which is established by the secondary PE device, is combined, so that the communication transaction between the first CE device and the second CE device can be implemented.

Optionally, based on any one of the foregoing embodiments, in this embodiment, the standby link of the slave PE device includes a standby PW link and a standby AC link; specifically, referring to fig. 1, the standby PW link refers to a link established between the first PE device and the slave PE device, and is also referred to as a PW side link, and the standby AC link refers to a link established between the slave PE device and the second CE device, and is also referred to as an AC side link. Accordingly, the bidirectional association between the standby link table entries stored in the slave PE device is the bidirectional association between the standby PW link table entry and the standby AC link table entry.

On this basis, in step S304, the pre-stored bidirectional association between the standby link table entries includes a bidirectional association between the standby PW link table entry and the standby AC link table entry, and then the step S305 establishes a bidirectional association between the standby link table entry of the failed active link and the Bypass PW table entry, which includes:

if the main PW link fails, establishing a bidirectional association relation between a standby PW link table entry and a Bypass PW table entry;

if the main AC link fails, establishing a bidirectional association relation between the standby AC link table entry and the Bypass PW table entry.

In specific implementation, also taking fig. 1 as an example for explanation, when a link between a first PE device and a master PE device in fig. 1 fails, after the master PE device executes a link switching operation, the slave PE device also needs to execute a link switching, that is, the slave PE device needs to modify a bidirectional association relationship stored in a forwarding chip thereof into a bidirectional association relationship between a standby PW link entry and a Bypass PW entry, that is, the standby PW link entry and the standby AC link entry in the slave PE device are not available, so that a communication relationship between a Bypass virtual link and a standby PW link is established, and in combination with the communication relationship established by the master PE device when the master PW link fails, the switched communication link is: and the primary AC link, the Bypass PW virtual link and the standby PW link are in bidirectional communication, so that the switching of the links is completed, and the forwarding chips of the primary PE equipment and the secondary PE equipment do not need to be operated frequently.

Similarly, when the primary AC link fails, that is, the link between the primary PE device and the second CE device in fig. 1 fails, the primary PE device also needs to perform link switching after performing the link switching operation, that is, the secondary PE device needs to modify the bidirectional association relationship stored in its forwarding chip into the bidirectional association relationship between the standby AC link table entry and the Bypass PW table entry, that is, the standby PW link table entry and the standby AC link table entry in the secondary PE device are not available, so that the communication relationship between the Bypass virtual link and the standby AC link is established, and in combination with the communication relationship established by the primary PE device when the primary AC link fails, the switched communication link is: and the primary PW link, the Bypass PW virtual link and the standby AC link are in bidirectional communication, so that the switching of the links is completed, and the forwarding chips of the primary PE equipment and the secondary PE equipment do not need to be operated frequently.

Optionally, based on any of the above embodiments, at least one Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device in the embodiment of the present application, and the at least one Bypass PW may protect both an AC side link and a PW side link. When the main link fails, the communication between the main PE equipment and the auxiliary PE equipment can be realized through at least one Bypass PW virtual link.

In a possible embodiment, when a Bypass PW is configured between a master PE device and a slave PE device, the Bypass PW may be referred to as a single Bypass PW, where a bidirectional association relationship and a Bypass PW entry stored in the master PE device and the slave PE device may refer to fig. 4a, where fig. 4a is a schematic diagram of an entry stored in a forwarding chip when a failure occurs in an active link. However, when the active PW link fails, the primary PE device may establish a bidirectional association relationship between the active AC link entry and the Bypass PW entry, please refer to fig. 4b, and similarly, the slave PE device may establish a bidirectional association relationship between the Bypass PW entry and the standby PW link, also refer to fig. 4 b. Similarly, when the primary AC link fails, the primary PE device may establish a bidirectional association relationship between the primary PW link entry and the Bypass PW entry, please refer to fig. 4c, and similarly, the secondary PE device may establish a bidirectional association relationship between the Bypass PW entry and the standby AC link, please refer to fig. 4 c.

For better understanding of the embodiment of the present application, an application scenario shown in fig. 5a is taken as an example for explanation, where the second PE device is a master PE device, the third PE device is a slave PE device, and the first PE device, the second PE device, and the third PE device are used to implement communication between the first CE device and the second CE device. As shown in fig. 4a, an entry stored in a forwarding chip of the second PE device is, in a fault-free scenario, the first CE device sends service data to the first PE device, and then the first PE device sends the service data to the second PE device through an active PW link between the first PE device and the second PE device.

When the primary PW link between the second PE device and the first PE device fails, please refer to fig. 5b, where the second PE device modifies the stored bidirectional association relationship to the bidirectional association relationship between the primary AC link entry and the Bypass PW entry, and also refer to fig. 4b, so that the link switching operation can be completed, and a process of re-issuing the Bypass PW entry to the forwarding chip is omitted, and similarly, the third PE device also needs to modify the stored bidirectional association relationship to establish BypassThe bidirectional association relationship between the ss PW table entry and the standby PW link table entry is realized, so that the communication link realized after the link switching is as follows: first CE device

First PE equipment

Third PE device

Second PE device

The second CE device, namely the first CE device sends the service data to the first PE device, then the first PE device detects the fault of the main PW link, the service data is sent to the third PE device through the standby PW link, then the third PE device sends the service data to the second PE device through the Bypass PW virtual link, and finally the second PE device sends the service data to the second CE device through the main AC link, and vice versa, so that the link switching of the main PW link can be realized when the fault occurs, and because the bidirectional association relationship and the Bypass PW are stored in the forwarding chip in advance, the forwarding chip does not need to be accessed frequently when the link is switched.

When the primary AC link between the second PE device and the second CE device fails, please refer to fig. 5c, where the second PE device modifies the bidirectional association stored therein to the bidirectional association between the primary PW link entry and the Bypass PW entry, and also refer to fig. 4c, so that the link switching operation can be completed, and a process of re-issuing the Bypass PW entry to the forwarding chip is omitted, and similarly, the third PE device also needs to modify the bidirectional association stored therein, and establishes the bidirectional association between the Bypass PW entry and the standby AC link entry, where a communication link implemented after link switching is: first CE device

First PE equipment

Second PE device

Third PE device

The second CE device, that is, the first CE device sends the service data to the first PE device, then the first PE device sends the service data to the second PE device through the active PW link, then the second PE device sends the service data to the third PE device through the Bypass PW virtual link, and finally the third PE device sends the service data to the second CE device through the standby AC link, and vice versa, thereby enabling the link switching when the active AC link fails to be achieved, and since the bidirectional association relationship and the Bypass PW are stored in the forwarding chip in advance, the forwarding chip does not need to be accessed frequently when the link is switched.

In one possible embodiment, when 2 Bypass PWs are configured between the master PE device and the slave PE device, the two Bypass PWs may be called as a dual Bypass PW, and when two Bypass virtual links Bypass PWs are configured between the master PE device and the slave PE device, a Bypass PW entry of the master PE device includes a PW Bypass PW entry and an AC Bypass PW entry; similarly, the Bypass PW entry of the slave PE device also includes a PW Bypass PW entry and an AC Bypass PW entry; fig. 6a may be referred to as a bidirectional association relationship and a Bypass PW entry stored in the master PE device and the slave PE device, where fig. 6a is a schematic diagram of an entry stored in a forwarding chip when the master link fails.

On this basis, if the primary PW link fails, when the primary PE device establishes a bidirectional association relationship between the primary AC link entry and the Bypass PW entry, the following process may be implemented: fig. 6b shows how to establish the bidirectional association relationship between the primary AC link table entry and the PW Bypass PW table entry. Correspondingly, when the slave PE device fails in the active PW link and establishes the bidirectional association relationship between the standby PW link entry and the Bypass PW entry, the following process may be implemented: establishing a bidirectional association relationship between the standby PW link entry and the AC Bypass PW entry, please refer to fig. 6 b.

If the primary AC link fails, the primary PE device may implement the following process when establishing the bidirectional association relationship between the primary PW link entry and the Bypass PW entry: and establishing a bidirectional association relationship between the main PW link entry and the AC Bypass PW entry, as shown in fig. 6 c. Correspondingly, when the slave PE device establishes a bidirectional association relationship between the standby AC link entry and the Bypass PW entry in the event of a failure of the primary AC link, the following process may be performed: establishing a bidirectional association relationship between the standby AC link entry and the PW Bypass PW entry, please refer to fig. 6 c.

In specific implementation, two Bypass PW virtual links between the master PE device and the slave PE device are configured as a virtual link formed by a PW Bypass PW of the master PE device and an AC Bypass PW of the slave PE device, and a virtual link formed by an AC Bypass PW of the master PE device and a PW Bypass PW of the slave PE device. Therefore, when the primary PW link of the primary PE device fails, in order for the primary PE device to provide communication, the primary PE device needs to modify the previously stored bidirectional association relationship into the bidirectional association relationship between the primary AC link entry and the PW Bypass PW entry, so as to implement bidirectional communication connection between the primary AC link and the PW Bypass PW virtual link; therefore, after the main PE device receives the service data through the main AC link, the service data is sent to the slave PE device through the PW Bypass PW virtual link based on the newly established bidirectional association relationship between the main AC link table entry and the PW Bypass PW table entry, and then the service data is sent outwards by the slave PE device. The method and the device not only realize normal sending of the service data, but also do not need to frequently operate the forwarding chips of the main PE device and the slave PE device, thereby effectively reducing the expense of the forwarding chips in the PE device.

When the main AC link of the main PE device fails, in order for the main PE device to provide communication, the main PE device needs to modify the previously stored bidirectional association relationship into the bidirectional association relationship between the main PW link entry and the AC Bypass PW entry, thereby implementing bidirectional communication connection between the main PW link and the AC Bypass PW virtual link. Therefore, after the main PE device receives the service data through the main PW link, the service data can be sent to the slave PE device through the AC Bypass PW link based on the bidirectional association relationship between the main PW link and the AC Bypass PW virtual link, and then the slave PE device sends the service data outwards. The method and the device not only realize normal sending of the service data, but also do not need to frequently operate the forwarding chips of the main PE device and the slave PE device, thereby effectively reducing the expense of the forwarding chips in the PE device.

To better understand the present embodiment, an application scenario shown in fig. 7a is taken as an example for explanation, where the second PE device is a master PE device, the third PE device is a slave PE device, and the first PE device, the second PE device, and the third PE device are used to implement communication between the first CE device and the second CE device. Fig. 6a shows that the entry stored in the forwarding chip of the second PE device is, in a fault-free scenario, the service data interaction between the first CE device and the second CE device may refer to fig. 5a, and is not described in detail here.

However, when the active PW link between the second PE device and the first PE device fails, please refer to fig. 7b, where the second PE device modifies the stored bidirectional association relationship into the bidirectional association relationship between the active AC link entry of the active AC link and the PW Bypass PW entry, as shown in fig. 6b, so that the link switching operation can be completed, and a process of re-issuing the PW Bypass PW entry to the forwarding chip is omitted, and similarly, the third PE device also needs to change the stored bidirectional association relationship into the bidirectional association relationship between the standby PW link entry of the standby link and the AC Bypass PW entry, where the switched communication link is: first CE device

First PE equipment

Third PE device

Second PE device

The second CE device, namely the first CE device, transmits the service data to the first PE device, and then the first PE device transmits the service data to the third PE device through the standby PW link, then the third PE device sends the service data to the second PE device through the AC Bypass PW virtual link, and the PW Bypass PW of the second PE device and the AC Bypass PW of the third PE device belong to the same virtual link, so that the second PE device receives the service data sent by the third PE device through the PW Bypass PW, and finally the second PE device sends the service data to the second CE device through the active AC link, the traffic data flow is also shown with reference to fig. 7b, and vice versa, thereby implementing link switching when the active PW link fails, and because the bidirectional association relation and the PW Bypass PW are stored in the forwarding chip in advance, the forwarding chip does not need to be frequently accessed during link switching.

When the primary AC link between the second PE device and the second CE device fails, please refer to fig. 7c, where the second PE device modifies the bidirectional association relationship stored therein to the bidirectional association relationship between the primary PW link entry and the AC Bypass PW entry, and also refer to fig. 6c, so that the link switching operation can be completed, and a process of re-issuing the AC Bypass PW entry to the forwarding chip is omitted, and similarly, the third PE device also needs to change the bidirectional association relationship stored therein to the bidirectional association relationship between the PW Bypass PW entry and the standby AC link entry, and thus the communication link implemented after link switching is: first CE device

First PE equipment

Second PE device

Third PE device

The second CE device, i.e. the first CE device, transmits the service data to the first PE device, and then the first PThe E device sends the service data to the second PE device through the active PW link, then the second PE device sends the service data to the third PE device through the AC Bypass PW virtual link, and the PW Bypass PW of the third PE device and the AC Bypass PW of the second PE device belong to the same virtual link, then the third PE device receives the service data sent by the second PE device through the PW Bypass PW, and finally the third PE device sends the service data to the second CE device through the standby AC link, and the flow direction of the service data thereof is also shown in fig. 7c, or vice versa, thereby not only realizing the link switching when the active AC link fails, but also not requiring frequent access to the forwarding chip when the link is switched because the bidirectional association relationship and the AC Bypass PW are stored in advance in the forwarding chip.

Optionally, based on any one of the above embodiments, the communication method provided in the embodiment of the present application further includes:

and deleting the main link table entry of the failed main link.

Specifically, when the primary link of the primary PE device fails, the link switching and the deletion of the failed primary link table entry are operations that need to be performed, so to further optimize the link switching performance, the link switching may be performed first, and then the primary link table entry may be deleted. That is, the communication link is switched again based on steps S301 to S306, and then the primary link table entry of the failed primary link is deleted. For example, when the primary PW link fails, firstly, the communication link is switched according to the method provided by the present application, and then the primary PW link entry is deleted; when the main AC link fails, the communication link is switched according to the method provided by the application, and then the list item of the main AC link is deleted. Therefore, normal sending of the service data is not influenced, the storage pressure of the forwarding chip can be relieved, and the processing performance of the forwarding chip is improved.

By implementing the communication method provided by any of the above embodiments of the present application, the bidirectional association relationship between the entries of the primary links and the Bypass PW entry are stored in advance in the forwarding chip of the PE device, so that when the primary PE device determines that any primary link fails, the bidirectional association relationship and the Bypass PW entry are directly read, then the bidirectional association relationship between the entry of the primary link of the non-failed primary link and the Bypass PW entry is re-established, then the service data is forwarded based on the newly established bidirectional association relationship, and in addition, the secondary PE device also needs to establish the bidirectional association relationship between the entry of the backup link of the failed primary link and the Bypass PW entry, so that the secondary PE device forwards the service data by using the newly established bidirectional association relationship, thus not only realizing the fast switching of paths and the normal forwarding of the service data, but also because the bidirectional association relationship and the Bypass PW entry are stored in advance in the forwarding chip, the forwarding chip of the PE equipment does not need to be operated frequently, and the pressure of the forwarding chip in the PE equipment is further reduced.

Optionally, an embodiment of the present application further provides a communication method, please refer to fig. 8, where the communication method is applied to a master PE device in a L2VPN of a two-layer virtual private network, and the L2VPN further includes a slave provider edge PE device, where a Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device, and then the master PE device may be implemented according to the following steps:

s801, when determining that any one main link fails, the main PE device acquires a prestored bidirectional association relationship between main link table entries and a Bypass PW table entry.

S802, the main PE device establishes a bidirectional association relation between the main link table entry except the failed main link and the Bypass PW table entry, and forwards the received service data by using the established bidirectional association relation.

S803, the primary PE device sends a path switching indication to the secondary PE device, so that the secondary PE device establishes a bidirectional association relationship between the backup link table entry of the failed primary link and the Bypass PW table entry, and forwards the service data by using the established bidirectional association relationship between the backup link table entry and the Bypass PW table entry.

Optionally, the active link includes an active PW link and an active AC link; the pre-stored bidirectional association relationship between the primary PW link table entry and the primary AC link table entry comprises the bidirectional association relationship between the primary PW link table entry and the primary AC link table entry; and

establishing a bidirectional association relation between a main link table entry except the failed main link and a Bypass PW table entry, comprising the following steps: if the main PW link fails, establishing a bidirectional association relation between the main AC link table entry and the Bypass PW table entry; if the main AC link fails, establishing a bidirectional association relation between the main PW link table entry and the Bypass PW table entry.

Optionally, at least one Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device in this embodiment of the present application.

Optionally, when two Bypass virtual link Bypass PWs are configured between the master PE device and the slave PE device, the Bypass PWs include a PW Bypass PW and an AC Bypass PW; then

If the primary PW link fails, establishing a bidirectional association relationship between the primary AC link table entry and the Bypass PW table entry, including: establishing a bidirectional association relation between a main AC link table item and a PW Bypass table item;

if the main AC link fails, establishing a bidirectional association relationship between the main PW link table entry and the Bypass PW table entry, including: and establishing a bidirectional association relation between the main PW link table entry and the AC Bypass PW table entry.

Optionally, the communication method provided in the embodiment of the present application further includes: and deleting the main link table entry of the failed main link.

It should be noted that, for the implementation of steps S801 to S803 in this embodiment, reference may be made to the description of the relevant steps of the main PE device in fig. 3 in this embodiment of the application, and details are not repeated here. By implementing the flow shown in fig. 8, since the bidirectional association relationship between the entries of the primary links and the Bypass PW entries are pre-stored in the primary PE device, when any primary link fails, the communication relationship between the primary link except the failed primary link and the Bypass PW virtual link is only established, so that the fast switching of the communication links can be quickly realized, and the forwarding chip of the primary PE device does not need to be frequently operated.

Optionally, an embodiment of the present application further provides a communication method, please refer to fig. 9, where the communication method is applied to a slave PE device in a L2VPN, and the L2VPN further includes a main provider edge PE device, where a Bypass virtual link Bypass PW is configured between the main PE device and the slave PE device, and then the slave PE device may be implemented according to the following steps:

s901, the slave PE equipment receives a path switching instruction sent by the master PE equipment, and acquires a prestored bidirectional association relationship between the standby link table items and a Bypass PW table item.

The path switching indication is sent by the primary PE device when determining that any primary link fails.

S902, the slave PE device establishes a bidirectional association relationship between a standby link table entry of the failed main link and a Bypass PW table entry.

S903, the slave PE equipment forwards the service data by using the established bidirectional association relationship between the standby link table entry and the Bypass PW table entry.

Optionally, the standby link provided in this embodiment includes a standby PW link and a standby AC link; the pre-stored bidirectional association between the standby link table entries comprises a bidirectional association between the standby PW link table entry and the standby AC link table entry; and

establishing a bidirectional association relationship between a standby link table item of a failed main link and a Bypass PW table item, comprising the following steps: if the main PW link fails, establishing a bidirectional association relation between a standby PW link table entry and a Bypass PW table entry; if the main AC link fails, establishing a bidirectional association relation between the standby AC link table entry and the Bypass PW table entry.

Optionally, at least one Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device provided in this embodiment.

Optionally, in this embodiment, when two Bypass virtual link Bypass PWs are configured between the master PE device and the slave PE device, the Bypass PWs include a PW Bypass PW and an AC Bypass PW; then

If the primary PW link fails, establishing a bidirectional association relationship between a standby PW link table entry and a Bypass PW table entry, including: establishing a bidirectional association relation between a standby PW link table item and an AC Bypass PW table item;

if the main AC link fails, establishing a bidirectional association relationship between a standby AC link table entry and a Bypass PW table entry, comprising: and establishing a bidirectional association relation between the standby AC link table entry and the PW Bypass PW table entry.

It should be noted that, in the embodiment of the present invention, the implementation of steps S901 to S903 may refer to the description of the relevant steps of the slave PE device in fig. 3, which is not described in detail herein. By implementing the flow shown in fig. 9, since the bidirectional association relationship between the entries of the standby links and the table entry of the Bypass PW is stored in the slave PE device in advance, when any one of the primary links fails, only the communication relationship between the standby link except the failed primary link and the Bypass PW virtual link needs to be established, so that the fast switching of the communication links can be realized quickly, and the forwarding chip of the PE device does not need to be operated frequently.

Based on the same inventive concept, the application also provides a communication device corresponding to the communication method. The implementation of the communication apparatus may refer to the above description of the communication method, which is not discussed here.

Referring to fig. 10, fig. 10 is a communication apparatus, according to an exemplary embodiment of the present disclosure, which is disposed in a L2VPN of a two-layer virtual private network, where the L2VPN further includes a slave provider edge PE device, a Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device, and the communication apparatus includes:

an obtaining module 1001, configured to obtain a prestored bidirectional association relationship between master link table entries and a Bypass PW table entry when determining that any master link fails;

an association relationship establishing module 1002, configured to establish a bidirectional association relationship between a primary link table entry except for the failed primary link and a Bypass PW table entry;

a forwarding module 1003, configured to forward the received service data using the established bidirectional association relationship;

a sending module 1004, configured to send a path switching indication to the slave PE device, so that the slave PE device establishes a bidirectional association relationship between a standby link entry of the failed primary link and a Bypass PW entry, and forwards service data by using the established bidirectional association relationship between the standby link entry and the Bypass PW entry.

In a possible embodiment, the active link includes an active PW link and an active AC link; the pre-stored bidirectional association relationship between the primary PW link table entry and the primary AC link table entry comprises the bidirectional association relationship between the primary PW link table entry and the primary AC link table entry; and

the association relationship establishing module 1002 is specifically configured to establish a bidirectional association relationship between an entry of the primary AC link and an entry of the Bypass PW if the primary PW link fails; if the main AC link fails, establishing a bidirectional association relation between the main PW link table entry and the Bypass PW table entry.

In a possible embodiment, in this embodiment, at least one Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device.

In a possible embodiment, when two Bypass virtual link Bypass PWs are configured between the master PE device and the slave PE device, a Bypass PW entry of the master PE device includes a PW Bypass PW entry and an AC Bypass PW entry; then

The association relationship establishing module 1002 is specifically configured to establish a bidirectional association relationship between an entry of the primary AC link and an entry of the PW Bypass PW if the primary PW link fails; if the main AC link fails, establishing a bidirectional association relation between the main PW link table entry and the AC Bypass PW table entry.

In a possible embodiment, please refer to fig. 10, which further provides the communication apparatus in this embodiment, the apparatus further includes:

the deleting module 1005 is configured to delete the active link table entry of the failed active link.

Referring to fig. 11, fig. 11 is a communication apparatus, according to an exemplary embodiment of the present disclosure, which is disposed in a L2VPN of a two-layer virtual private network, where the L2VPN further includes a primary provider edge PE device, a Bypass virtual link Bypass PW is configured between the primary PE device and the secondary PE device, and the communication apparatus includes:

a receiving module 1101, configured to receive a path switching indication sent by the primary PE device, and obtain a prestored bidirectional association relationship between standby link table entries and a Bypass PW table entry, where the path switching indication is sent by the primary PE device when determining that any primary link fails;

an association relationship establishing module 1102, configured to establish a bidirectional association relationship between a standby link entry of the failed primary link and a Bypass PW entry;

a forwarding module 1103, configured to forward the service data using the established bidirectional association relationship between the standby link table entry and the Bypass PW table entry.

In one possible embodiment, the standby link provided by this embodiment includes a standby PW link and a standby AC link; the pre-stored bidirectional association between the standby link table entries comprises a bidirectional association between the standby PW link table entry and the standby AC link table entry; and

the association relationship establishing module 1102 is specifically configured to establish a bidirectional association relationship between a standby PW link entry and a Bypass PW entry if the primary PW link fails; if the main AC link fails, establishing a bidirectional association relation between the standby AC link table entry and the Bypass PW table entry.

In a possible embodiment, at least one Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device.

In a possible embodiment, when two Bypass virtual link Bypass PWs are configured between a master PE device and a slave PE device, a Bypass PW entry of the slave PE device includes a PW Bypass PW entry and an AC Bypass PW entry; then

The association relationship establishing module 1102 is specifically configured to establish a bidirectional association relationship between a standby PW link entry and an AC Bypass PW entry if the primary PW link fails; if the main AC link fails, establishing a bidirectional association relation between a standby AC link table entry and a PW Bypass PW table entry.

An embodiment of the present application provides a provider edge PE device, which may be a master PE device or a slave PE device, as shown in fig. 12, including a processor 1201 and a machine-readable storage medium 1202, where the machine-readable storage medium 1202 stores machine-executable instructions capable of being executed by the processor 1201, and the processor 1201 is caused by the machine-executable instructions to execute the communication method provided in any embodiment of the present application.

The machine-readable storage medium may include a RAM (Random Access Memory) and a NVM (Non-volatile Memory), such as at least one disk Memory. Alternatively, the machine-readable storage medium may be at least one memory device located remotely from the processor.

The Processor may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but also a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component.

In addition, the embodiment of the application provides a machine-readable storage medium, and the machine-readable storage medium stores machine executable instructions, and when the machine executable instructions are called and executed by a processor, the processor is caused to execute the communication method provided by any embodiment of the application.

As for the PE device and the machine-readable storage medium, the content of the related method is substantially similar to that of the foregoing method embodiment, so that the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment. The implementation process of the functions and actions of each unit in the above device is specifically described in the implementation process of the corresponding step in the above method, and is not described herein again.

For the device embodiments, since they substantially correspond to the method embodiments, reference may be made to the partial description of the method embodiments for relevant points. The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the application. One of ordinary skill in the art can understand and implement it without inventive effort.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A communication method, applied to a primary provider edge PE device in a layer two virtual private network, L2, VPN, the L2VPN further comprising a secondary provider edge PE device, wherein a Bypass virtual link, Bypass PW, is configured between the primary PE device and the secondary PE device, and the method comprises:

2. The method of claim 1, wherein the active link comprises an active PW link and an active AC link; the pre-stored bidirectional association relationship between the primary PW link table entry and the primary AC link table entry comprises the bidirectional association relationship between the primary PW link table entry and the primary AC link table entry; and

establishing a bidirectional association relation between a main link table entry except the failed main link and a Bypass PW table entry, comprising the following steps:

3. The method of claim 2, wherein at least one Bypass virtual link Bypass PW is configured between the master PE device and a slave PE device.

4. The method of claim 3, wherein when two Bypass virtual link Bypass PWs are configured between the master PE device and the slave PE device, the Bypass PW entry of the master PE device comprises a PW Bypass PW entry and an AC Bypass PW entry; then

If the primary PW link fails, establishing a bidirectional association relationship between the primary AC link table entry and the Bypass PW table entry, including:

establishing a bidirectional association relation between a main AC link table item and a PW Bypass table item;

if the main AC link fails, establishing a bidirectional association relationship between the main PW link table entry and the Bypass PW table entry, including:

and establishing a bidirectional association relation between the main PW link table entry and the AC Bypass PW table entry.

5. The method of any one of claims 1 to 4, further comprising:

and deleting the main link table entry of the failed main link.

6. A communication method, wherein the communication method is applied to a secondary provider edge PE device in a L2VPN of a two-layer virtual private network, the L2VPN further includes a primary provider edge PE device, wherein a Bypass virtual link Bypass PW is configured between the primary PE device and the secondary PE device, and the method includes:

7. The method of claim 6, wherein the backup link comprises a backup PW link and a backup AC link; the pre-stored bidirectional association between the standby link table entries comprises a bidirectional association between the standby PW link table entry and the standby AC link table entry; and

establishing a bidirectional association relationship between a standby link table item of a failed main link and a Bypass PW table item, comprising the following steps:

8. The method of claim 7, wherein at least one Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device.

9. The method of claim 8, wherein when two Bypass virtual link Bypass PWs are configured between the master PE device and the slave PE device, the Bypass PW entry of the slave PE device comprises a PW Bypass PW entry and an AC Bypass PW entry; then

If the primary PW link fails, establishing a bidirectional association relationship between a standby PW link table entry and a Bypass PW table entry, including:

establishing a bidirectional association relation between a standby PW link table item and an AC Bypass PW table item;

if the main AC link fails, establishing a bidirectional association relationship between a standby AC link table entry and a Bypass PW table entry, comprising:

and establishing a bidirectional association relation between the standby AC link table entry and the PW Bypass PW table entry.

10. A communication apparatus, characterized in that, a primary provider edge PE device is disposed in a L2VPN, the L2VPN further includes a secondary provider edge PE device, wherein a Bypass virtual link Bypass PW is configured between the primary PE device and the secondary PE device, and the apparatus comprises:

11. A communication apparatus, characterized in that, a slave provider edge PE device is disposed in a layer two virtual private network L2VPN, the L2VPN further includes a master provider edge PE device, wherein a Bypass virtual link Bypass PW is configured between the master PE device and the slave PE device, and the apparatus comprises: