CN102104529B - Method and equipment for realizing message transmission in provider bridge transfer (PBT) network - Google Patents

Abstract

The invention discloses a method and equipment for realizing message transmission in a PBT network. There are multiple operator edge equipment PEs in the PBT network; A primary virtual circuit PW corresponding to a service instance supported by the first PE and the second PE, and a standby PW corresponding to the primary PW is configured between the first PE and the third PE, and the third PE also supports the service instance The method includes: the first PE detects the primary PW, and when detecting that the primary PW is abnormal, switches the forwarding of service packets in the service instance corresponding to the primary PW to the primary PW on the corresponding standby PW. The present invention can avoid the problem in the prior art that when the primary ESP detects that the primary ESP is abnormal, the forwarding work of service messages in all service instances carried by the primary ESP is concentrated on the backup ESP.

Description

A method and device for realizing message transmission in a PBT network

technical field

The present invention relates to the field of network technology, in particular to a method and device for realizing message transmission in a provider backbone network transmission (PBT: Provider Bridge Transfer) network.

Background technique

In the PBT network, also known as PBBN-TE, the Ethernet forwarding path (ESP: Ethernet SwitchPath) can realize highly reliable and flexible point-to-point transmission services. Here, the ESP can be identified by <BDMAC, BVLAN), where BDMAC is the destination MAC address of the ESP, and BVLAN is the VLAN to which the ESP belongs.

In order to improve the reliability of ESP forwarding services, multiple ESPs can be configured to the same BDMAC, one of which is used as the primary ESP, and the others are used as backup ESPs; as shown in Figure 1, from the carrier edge equipment (PE) 1 to PE3 There are two mutually backup ESPs, the main ESP and the backup ESP. Usually, one ESP can carry multiple MAC-IN-MAC service instances (referred to as service instances). In the case of normal forwarding, the business packets in the service instance are forwarded along the main ESP. If the main ESP is abnormal during the service packet forwarding process, for example, the service instance has relatively high delay requirements, when the main ESP has relatively little delay When it is determined that the active ESP is abnormal, the active-standby switchover is performed so that the standby ESP replaces the abnormal active ESP. That is, at this time, the service packet forwarding work in all service instances carried by the abnormal active ESP is switched to Prepare the ESP.

However, since one ESP can carry multiple service instances, different service instances have different delay requirements for ESP. For example, service instance A has higher delay requirements. Switch to the standby ESP; while service instance B has low latency requirements and can accept a longer delay. In this way, if the delay of the main ESP does not meet the requirements of the service instance A when the service message in the service instance A is forwarded along the main ESP, it is determined that the main ESP is abnormal, and the main ESP will be executed. Active/standby switchover, in this way, other service instances carried by the active ESP, such as the forwarding of business packets in service instance B, will be concentrated on the standby ESP. In fact, service instance B has low latency requirements, and the service packets in it The forwarding work can also be performed through the main ESP, and there is no need to concentrate on the standby ESP. Those skilled in the art know that the resources of the standby ESP are very valuable. If the forwarding work of service messages that is not necessary to be performed by the standby ESP is concentrated on the standby ESP, this obviously greatly wastes the resources of the standby ESP and increases the burden on the standby ESP. Packet forwarding burden.

Contents of the invention

The present invention provides a method and equipment for realizing message transmission in a PBT network, so as to prevent the forwarding work of service messages in all service instances carried by the main ESP from being centralized to the backup in the prior art when the main ESP is detected to be abnormal. The problems brought on by ESP.

A method for transmitting messages in a PBT network, where there are multiple operator edge devices PEs in the PBT network; pre-created between the first PE and the second PE supported by the first PE and the second PE A primary virtual circuit PW corresponding to a service instance, and creating a standby PW corresponding to the primary PW between the first PE and the third PE, and the third PE also supports the service instance; the method includes:

The first PE detects the primary PW, and when detecting that the primary PW is abnormal, switches the forwarding of service packets in the service instance corresponding to the primary PW to the standby PW corresponding to the primary PW .

A packet transmission device in a PBT network, where there are multiple operator edge devices PE in the PBT network; the device includes a detection unit, a main PW control unit, a standby PW control unit, and a switching unit; wherein,

The main PW control unit controls the main PW between the device and a PE in the PBT network, and the main PW corresponds to a service instance supported by the device and the PE;

The standby PW control unit controls a standby PW between the device and another PE in the PBT network, the standby PW corresponds to the primary PW, and the other PE supports the service instance;

The detection unit is used to detect the main PW controlled by the main PW control unit, and when the main PW is detected to be abnormal, send a switching notification to the switching unit;

The switching unit is configured to receive the switching notification, and switch the forwarding of service packets in the service instance corresponding to the primary PW to the standby PW corresponding to the primary PW controlled by the standby PW control unit.

It can be seen from the above technical solutions that in the present invention, by establishing a primary PW corresponding to a service instance, the primary PW is used to forward service packets in the corresponding service instance. When the primary PW is abnormal, only the primary PW is corresponding The forwarding of business packets in the service instance of the service instance is concentrated to the standby PW corresponding to the main PW, and the normal working status of other main PWs that have not experienced abnormalities is maintained. The problem caused by the centralized forwarding of service packets in all service instances carried by the active ESP to the standby ESP.

Furthermore, since the present invention realizes the separate detection and protection of PWs corresponding to different service instances, it can provide users with services of different link qualities according to the user needs of different service instances, and greatly improves the work efficiency of the standby PW. .

Description of drawings

Fig. 1 is the schematic diagram of ESP in the PBT network in the prior art;

Fig. 2 is the basic flowchart provided by the embodiment of the present invention;

FIG. 3 is a detailed flowchart provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of a PBT network provided by an embodiment of the present invention;

Fig. 5 is a device structure diagram provided by an embodiment of the present invention.

Detailed ways

In the embodiment of the present invention, in order to avoid abnormalities in the prior art when the master ESP executes the forwarding of service messages in a service instance, the business message forwarding work of all service instances carried by the master ESP is centralized to the backup ESP. In view of the defects caused, a solution to provide corresponding link protection for different service instances is proposed, which is as follows. In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to FIG. 2, FIG. 2 is a basic flowchart provided by an embodiment of the present invention. In this embodiment, a primary virtual circuit (PW, where PW is two Layer 2 VPN instance such as a two-way connection between PEs), and configure the standby PW corresponding to the primary PW between the first PE and the third PE, the third PE also supports the service instance, after that, as shown in Figure 2 As indicated, the process may include the following steps:

In step 201, the first PE detects the main PW, and when it is detected that the main PW is abnormal, the following step 202 is performed.

Step 202: Switch the forwarding of service packets in the service instance corresponding to the primary PW to the standby PW corresponding to the primary PW.

So far, through the above steps, the process provided by the embodiment of the present invention is realized.

The method provided by the embodiments of the present invention is briefly described above, and the above method will be described in detail below in conjunction with specific embodiments.

Referring to FIG. 3, FIG. 3 is a detailed flowchart provided by an embodiment of the present invention. As shown in Figure 3, this embodiment may include the following steps:

Step 301, create a service instance 1 on PE1, and configure the MAC address of the opposite end (denoted as PE2) involved in the primary PW (denoted as primary PW1) corresponding to the service instance 1.

Here, the service instance 1 can be created according to the actual needs of the user, and the peer end (denoted as PE2) involved in the main PW1 used to transmit the service message in the service instance 1 is determined, and then the determined peer end (denoted as PE2) is determined. ) MAC address is configured on PE1.

In this way, through this step 301, PE1 can determine that there is a primary PW1 corresponding to the service instance 1 between itself and PE2.

It should be noted that in this embodiment, the created service instance 1 may specifically include: an identifier of the service instance (marked as I-SID) and a VLAN identifier specifying the outer encapsulation of the service instance (marked as BVLAN). In practical applications, multiple service instances can be configured on PE1 according to the actual needs of users during PBT networking. Here, only one of the service instances is described, and other situations are similar to those of the service instance.

Step 302, configure the MAC address of the peer end (denoted as PE3) involved in the standby PW1 corresponding to the primary PW1 on PE1.

Here, in step 302, the peer end involved in the standby PW1 corresponding to the primary PW1 (in essence, the standby PW1 also corresponds to the service instance 1) used to transmit service packets in the service instance 1 can be determined according to the actual needs of the user (record PE3), and then configure the MAC address of the determined peer (denoted as PE3) on PE1.

In this way, through this step 302, PE1 can determine the standby PW1 existing between itself and PE3.

So far, the configuration on PE1 has been completed through the above steps 301 to 302. For specific implementation, take the PBT network shown in Figure 4 as an example. If the MAC address of PE1 is 00-00-00-01-01-01, PE2 The MAC address of PE3 is 00-00-00-02-01-01, and the MAC address of PE3 is 00-00-00-03-01-01, then the configuration operations from step 301 to step 302 can be represented by the following codes:

i-sid 4532create //created service instance ID I-SID is 4532;

i-sid 4532name″60574″ //The name of the device that provides the service instance is "60574";

i-sid 4532b-vlan 300 //Specify the BVLAN encapsulated in the outer layer of the service instance as 300;

i-sid peer 00-00-00-02-01-01master id 1 //Specify the MAC address and identity of the peer involved in the PW corresponding to the I-SID instance. Here, the identity of the PW is master (master) ;

i-sid peer 00-00-00-03-01-01slave id 1 //Specify the MAC address and identity of the peer involved in the PW corresponding to the I-SID instance. Here, the identity of the PW is the standby (slave) .

Preferably, in order to facilitate PE1 to detect the primary PW1 corresponding to service instance 1, step 303 may also be executed in this embodiment.

Step 303, configure the PW detection time interval T corresponding to the primary PW1 on PE1 and the maximum number of times N that the detection message cannot be received;

Here, PE1 can use the connectivity error detection (cfd) detection protocol to realize the detection of the primary PW, wherein, when detecting the primary PW1, it needs to send the peer PE of the primary PW1 every PW detection time interval T corresponding to the primary PW1 (denoted as PE2) sends a detection message, and at the same time receives the detection message sent by the peer PE2 every PW detection time interval T corresponding to the primary PW1 (see the configuration of PE2 for details), where N is that PE1 cannot receive the detection message related to the primary PW1 The maximum number of detection packets sent by the peer PE. When the number N is reached, PE1 can determine that the primary PW1 is abnormal. For details, refer to the description of subsequent steps 307 to 309.

Still taking the network shown in Figure 4 as an example, step 303 can be specifically implemented by the following code:

i-sid peer 00-00-00-02-01-01 cfd enable T N. Wherein, T is the detection time interval, and N is the maximum number of times that PE1 fails to receive detection packets sent by peer PEs involved in the primary PW1.

It should be noted that there is no fixed time sequence from step 301 to step 303, for example, they may be performed at the same time, etc., which are not limited here.

Step 304, create a service instance 1 on PE2, and configure the MAC address of PE1, which is the opposite end involved in the primary PW1.

Here, according to the description of step 301, it can be known that the primary PW1 corresponding to service instance 1 is essentially a link between PE1 and PE2. Therefore, for the convenience of implementation, after completing the configuration of PE1, corresponding configurations need to be performed on PE2, that is, , create service instance 1, and configure the MAC address of the peer involved in the primary PW1 (relative to PE2, the peer involved in the primary PW should be PE1), as shown in the following code:

i-sid 4532create //Create a service instance and specify the I-SID

i-sid 4532name "60574"

i-sid 4532b-vlan 300 //Specify the outer encapsulation BVLAN for the service instance

i-sid peer 00-00-00-01-01-01 //Specify the MAC address of PE1 involved in the PW corresponding to the I-SID instance.

In order to detect the primary PW1 corresponding to the service instance 1, the following step 305 may also be executed on PE2.

Step 305, configure the PW detection time interval T corresponding to the primary PW1 on PE2.

Here, the PW detection time interval T in step 305 can be the same as the PW detection time interval in step 303, which can be specifically implemented by the following code:

i-sid peer 00-00-00-01-01-01 cfd enable T. Among them, 00-00-00-01-01-01 is the peer end, that is, the MAC address of PE1.

So far, through the above steps 304 to 305, the configuration of PE2 can be completed.

Step 306, create service instance 1 on PE3, and configure the MAC address of the peer involved in the standby PW1 corresponding to the service instance 1 (here, relative to PE3, the peer involved in the standby PW1 should be PE1).

Here, this step 306 may be similar to the above step 304 .

So far, through the above steps, the operation of creating a primary PW corresponding to the service instance supported by PE1 and PE2 between PE1 and PE2, and creating a backup PW corresponding to the primary PW between PE1 and PE3 is realized.

It should be noted that, in this embodiment of the present invention, multiple primary PWs corresponding to multiple service instances can be created between PE1 and PE2 according to the above-mentioned similar operations, and standby PWs corresponding to each primary PW can be created between PE1 and PE3. Operation, for each primary PW, its specific operation is similar to the operation performed by the primary PW1 in this embodiment, and will not be repeated here.

Step 307: PE1 sends the first detection message with added MAC-in-MAC tunnel header to PE2 every preset PW detection time interval corresponding to primary PW1, and receives PE2 every preset primary PW1 corresponding PW detection time interval The sent second detection packet carrying the MAC-in-MAC tunnel header.

In this embodiment, the MAC-in-MAC tunnel header carried in the first detection message or the second detection message carries I-SID1, BVLAN, source MAC address and destination MAC address, taking the first detection message as an example , then in the MAC-in-MAC tunnel header carried by the first detection message, the destination MAC address is 00-00-00-02-01-01, and the source MAC address is 00-00-00-01-01-01, The I-SID is 4532 and the BVLAN is 300. Here, the reason why the first detection packet or the second detection packet carries I-SID1, BVLAN, source MAC address and destination MAC address is mainly to let the PE receiving the first detection packet or the second detection packet know Therefore, it can be clearly known that the I-SID, BVLAN, source MAC address, and destination MAC address carried in the detection packet are used to identify the primary PW, which can be referred to as Indicates the identification information of the primary PW. For example, when PE1 receives the second detection packet, according to the I-SID1, BVLAN, source MAC address and destination MAC address carried in the second detection packet, it is easy to identify that the second detection packet is used to detect the I-SID1. Primary PW1 corresponding to SID1. Similarly, after receiving the first detection packet, PE2 knows that the detection packet is used to detect the primary PW1 corresponding to I-SID1 according to I-SID1, BVLAN, source MAC address and destination MAC address.

Specifically, in this embodiment, when PE1 forwards the first detection packet in step 307, it can first send the first detection packet to be sent to the intermediate device BCB, and the BCB can transmit the first detection packet according to the MAC-in-MAC tunnel header. Forward the first detection packet with the source MAC address and destination MAC address. The situation that PE2 forwards the second detection packet is similar to the situation that PE1 forwards the first detection packet.

Step 308, if PE1 fails to continuously receive the second detection packets sent by the peer end involved in the primary PW1, that is, PE2, for a configured maximum number of times N, determine that the primary PW1 is abnormal. Afterwards, step 309 is performed.

For example, since PE2 sends the second detection packet to PE1 every PW detection time interval configured corresponding to the primary PW1, PE1 in step 308 cannot continuously receive the second detection packet sent by the peer end involved in the primary PW1, that is, PE2. The number of detection packets reaches the configured maximum number N. In essence, PE1 has not received the second detection packet for N PW detection intervals since it last received the second detection packet sent by PE2. abnormal.

Here, in order to save resources, when it is determined that the primary PW1 is abnormal, the abnormality can be notified to PE2, wherein the abnormality notification carries information about the abnormality of the primary PW1. The status of the primary PW1 is set to invalid or block.

Step 309: Switch the forwarding of service packets in the service instance corresponding to the active PW1 to the standby PW1 corresponding to the active PW1, and the standby PW1 takes over the service forwarding work of the abnormal active PW1.

So far, through the above operations, the process provided by the embodiment of the present invention can be realized. It can be seen that through the above steps, when an abnormality occurs on the primary PW, only the forwarding of service packets in the service instance corresponding to the primary PW is centralized to the standby PW corresponding to the primary PW, and the primary PW corresponding to other service instances PW has nothing to do, that is, maintain the normal working state of the main PW corresponding to other service instances that do not have abnormalities. In this way, the problem caused by the prior art that when the primary ESP is detected to be abnormal, the forwarding of service packets in all service instances carried by the primary ESP is avoided.

For example, taking the PBT network shown in Figure 4 as an example, if there are multiple service instances on PE1 and PE2, each service instance corresponds to a primary PW, so for each primary PW, the The detection time and accuracy require that the primary PW be detected. For services in service instances with small delays, such as voice and video, the detection accuracy is high, and the detection time of the primary PW corresponding to the service instance is configured to be short. For services with large delays Services in the example, such as emails and text messages, have low detection accuracy and long configuration detection time. In this way, when an abnormality occurs on the primary PW corresponding to one of the service instances, only the service packet forwarding work in the service instance corresponding to the primary PW is switched to the standby PW, and for some primary PWs that do not have abnormalities, the service is still maintained. The normal working state of the primary PW, that is, still forwarding on the primary PW along the original path, realizes the purpose of separate detection and protection of PWs corresponding to different service instances, so as to provide users with different links according to the user needs of different service instances The road quality service also greatly improves the work efficiency of the standby PW.

The method provided by the embodiment of the present invention has been described above, and the device provided by the present invention will be described below in conjunction with specific embodiments.

Referring to FIG. 5, FIG. 5 is a device structure diagram provided by an embodiment of the present invention. As shown in Figure 5, the device includes a main PW control unit 501, a standby PW control unit 502, a detection unit 503, and a switching unit 504;

Wherein, the main PW control unit 501 controls the main PW between the device and a PE in the PBT network, and the main PW corresponds to a service instance supported by the device and the PE;

The standby PW control unit 502 controls a standby PW between the device and another PE in the PBT network, the standby PW corresponds to the primary PW, and the other PE supports the service instance;

The detection unit 503 is configured to detect the main PW controlled by the main PW control unit 501, and when detecting that the main PW is abnormal, send a switching notification to the switching unit 504;

The switching unit 504 is configured to receive the switching notification, and switch the forwarding of service packets in the service instance corresponding to the primary PW to the standby PW corresponding to the primary PW controlled by the standby PW control unit 502 .

Preferably, when there are multiple primary PWs corresponding to multiple service instances between the device and the PE, the detection unit detects each primary PW, and when one of the primary PWs is detected to be abnormal, only the The forwarding of service packets in the service instance corresponding to the abnormal primary PW is switched to the backup PW corresponding to the primary PW, and the normal working status of other primary PWs that are not abnormal is maintained.

Preferably, the detection unit 503 may include:

The sending subunit 5031 is configured to, for each primary PW existing between the device and the PE, send a first detection message to the Peers involved in the primary PW;

The receiving subunit 5032 is configured to receive the second detection message sent by the peer involved in the main PW every PW detection time interval corresponding to the main PW pre-configured on itself;

The determining subunit 5033 is configured to determine that the main PW is abnormal if the receiving subunit 5032 fails to receive the second detection message sent by the opposite end for N consecutive preset PW detection time intervals; otherwise, determine that the main PW PW is normal.

Preferably, the detection unit 503 also includes:

The enabling subunit 5034 is configured to enable the pre-configured detection function of the main PW;

The sending subunit 5032 is configured to send a first detection message to the peer involved in the main PW when the enabling subunit 5034 enables the detection function of the main PW.

Preferably, a MAC-in-MAC tunnel header carrying primary PW identification information is added to the first detection message sent by the sending subunit 5032, wherein the primary PW identification information includes: service instance ID, external Layer encapsulation VLAN identification, source MAC address and destination MAC address.

It can be seen from the above technical solutions that in the present invention, by establishing a primary PW corresponding to a service instance, the primary PW is used to forward service packets in the corresponding service instance. When the primary PW is abnormal, only the primary PW is corresponding The forwarding of service packets in the service instance is centralized to the standby PW corresponding to the main PW, which has nothing to do with other service instances. In this way, all service instances carried by the main ESP when the main ESP is detected to be abnormal in the prior art are avoided. The problems caused by the centralization of the business message forwarding work in the network to the standby ESP.

Furthermore, since the present invention realizes the separate detection and protection of PWs corresponding to different service instances, it can provide users with services of different link qualities according to the user needs of different service instances, and greatly improves the work efficiency of the standby PW. .

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (8)

1. realize the transmission method of message in a kind of PBT network, described PBT network has a plurality of operator edge equipment PE; It is characterized in that, between the first PE and the second PE in advance for described first PE and all The multiple service instances supported by the second PE are respectively configured with corresponding primary virtual circuit PWs, and the primary PWs configured for the multiple service instances between the first PE and the third PE are respectively configured with corresponding standby PWs. The PE also supports said plurality of service instances; the method comprising: When the first PE detects multiple primary PWs, it detects each primary PW according to the PW detection time interval corresponding to each primary PW, and when detecting that the primary PW is abnormal, adds The forwarding of service packets is switched to the standby PW corresponding to the abnormal primary PW, and the normal working status of other primary PWs that are not abnormal is maintained; Wherein, the detection of each primary PW by the first PE according to the PW detection time interval corresponding to each primary PW includes: For each primary PW existing between itself and the second PE, the first PE sends a first detection message to the second PE every PW detection time interval corresponding to the primary PW preconfigured on itself, and receives A second detection message sent by the second PE every PW detection time interval corresponding to the primary PW pre-configured on itself; If the second detection message sent by the second PE is not received for consecutive preset N PW detection time intervals, it is determined that the primary PW is abnormal; otherwise, it is determined that the primary PW is normal. 2. The method according to claim 1, wherein the pre-configuring between the first PE and the second PE corresponds to multiple service instances supported by the first PE and the second PE respectively The main virtual circuit PW, and the main PW configured between the first PE and the third PE for the multiple service instances respectively configure corresponding standby PWs include: Create a service instance on the first PE, and configure the MAC address of the peer second PE involved in the primary PW corresponding to the service instance and the MAC address of the peer third PE involved in the corresponding backup PW; Create the service instance on the second PE, and configure the MAC address of the peer first PE involved in the primary PW corresponding to the service instance; The service instance is created on the third PE, and the MAC address of the peer first PE involved in the standby PW corresponding to the service instance is configured. 3. The method according to claim 1, wherein the first PE sends the first detection message at a preset PW detection time interval when the pre-configured primary PW detection function is enabled to the second PE; The second PE sends a second detection message to the first PE at a preset PW detection time interval when the pre-configured primary PW detection function is enabled. 4. The method according to claim 1, wherein a MAC-in-MAC tunnel header is added in the first detection message sent by the first PE and the second detection message sent by the second PE, and the tunnel The primary PW identification information is carried in the header, so that the PE receiving the first detection message or the second detection message knows which primary PW the received detection message is used to detect. 5 . The method according to claim 4 , wherein the primary PW identification information includes: service instance ID, outer encapsulation VLAN identification of the service instance, source MAC address and destination MAC address. 6. A transmission device for realizing messages in a PBT network, the device is applied to a PBT network with a plurality of operator edge devices PE; it is characterized in that the device includes a detection unit, a main virtual circuit PW control unit, a backup PW control unit and switching unit; wherein, The main PW control unit controls multiple main PWs between the device and a PE in the PBT network, and the multiple main PWs are respectively configured for multiple service instances supported by the device and the PE; The standby PW control unit controls the standby PWs configured respectively corresponding to the primary PWs configured for the multiple service instances between the device and another PE in the PBT network, and the other PE supports the multiple service instances instance; The detection unit is configured to detect each main PW controlled by the main PW control unit according to the PW detection time interval corresponding to each main PW when detecting multiple main PWs, and when the main PW is detected to be abnormal , send a switching notification to the switching unit, and maintain the normal working status of other main PWs that are not abnormal; The switching unit is configured to receive the switching notification, and switch the forwarding of service packets in the service instance corresponding to the abnormal primary PW to the standby PW corresponding to the abnormal primary PW controlled by the standby PW control unit; The detection unit includes: The sending subunit is configured to, for each main PW existing between the device and the PE, send a first detection message to the main PW every PW detection time interval corresponding to the main PW pre-configured on itself The peer involved in the PW; The receiving subunit is configured to receive the second detection message sent by the peer involved in the main PW every PW detection time interval corresponding to the main PW pre-configured on itself; The determining subunit is configured to determine that the main PW is abnormal if the receiving subunit fails to receive the second detection message sent by the opposite end for N consecutive preset PW detection time intervals; otherwise, determine that the main PW is abnormal; PW is normal. 7. The device according to claim 6, wherein the detection unit further comprises: an enabling subunit, configured to enable a pre-configured detection function of the primary PW; The sending subunit is configured to send a first detection message to the peer involved in the main PW when the enabling subunit enables the detection function of the main PW. 8. The device according to claim 6, wherein a MAC-in-MAC tunnel header carrying primary PW identification information is added to the first detection message sent by the sending subunit, wherein the primary PW identification The information includes: service instance ID, outer encapsulation VLAN ID of the service instance, source MAC address and destination MAC address.