CN102833122A - Loopback detection method and system - Google Patents

Abstract

The present invention discloses a loopback detection method and system. The source maintenance end node sends a loopback message to the destination maintenance point, and the loopback message contains the information corresponding to a specific transmission path among multiple equivalent transmission paths to the destination maintenance point. Flow identifier; after the destination maintenance point receives the loopback message, it sends a loopback response message to the source maintenance end node, and the loopback response message contains the flow identifier corresponding to the reverse common path transmission path to the source maintenance end node; the source maintenance end node After the end node receives the loopback response message and the detection is correct, it returns a notification that the loopback detection is successful. The present invention expands the working mechanism of Ethernet loopback detection stipulated in the IEEE802.1ag standard, and can perform loopback detection on a specific path among multiple equal-cost paths, thereby supporting the existence of equal-cost multipaths between two maintenance points. Application scenarios.

Description

A loop detection method and system

technical field

The present invention relates to the technical field of communications, in particular to a loopback detection method and system.

Background technique

In the current Ethernet, the standard organization Institute of Electrical and Electronics Engineers (IEEE) has formulated a set of Ethernet operation, administration and maintenance (OAM) working mechanism, and It was officially released as the 802.1ag standard in 2007.

The IEEE 802.1ag standard defines the OAM functional entity in Ethernet, including Maintenance End Point (MEP) located at both ends of the Ethernet transmission path, and Maintenance Intermediate Point (Maintenance Intermediate Point, MEP) located in the middle of the Ethernet transmission path. referred to as MIP). Among them, the maintenance end node and the maintenance intermediate point are collectively referred to as Maintenance Point (MP for short).

Each switch (Switch, SW for short) on the Ethernet can create MPs based on ports. Loopback detection is one of the Ethernet OAM functions defined by the IEEE 802.1ag standard. This function runs from MEP to MEP or MEP to MIP to detect connection failures of the entire or a section of the Ethernet transmission path.

Figure 1 is a schematic diagram of the loopback detection mechanism defined by the existing IEEE 802.1ag standard, and as shown in Figure 1, the existing Ethernet loopback detection mechanism includes the following main steps:

Step 1: After the loopback detection function is enabled, the MEP sends a LoopBack Message (LBM for short) to a certain MIP or peer MEP, and the message reaches the destination MIP or MEP along a fixed single path.

Step 2: After the destination MIP or MEP receives the loopback message and detects it is correct, it sends a loopback response (LoopBack Reply, LBR for short) to the source MEP that sent the loopback message, and the message arrives at the source MEP along the reverse fixed single path .

Step 3: After the source MEP that sends the loopback message receives the loopback response and detects no errors, it returns a notification that the loopback detection is successful to the operator.

The IEEE 802.1Qbp project is developing the working mechanism of Equal Cost Multi-Path (ECMP for short) in Ethernet to realize load sharing of service traffic on Equal Cost Multi-Path and improve link utilization in Ethernet. The 802.1Qbp project stipulates that for an Ethernet that supports equal-cost multi-path, the network edge switch must add a forwarding label F-tag to the Ethernet frame entering the network. When the F-tag Ethernet frame leaves the network, the network edge The switch will strip the F-tag carried by the Ethernet frame.

Figure 2 describes the specific encapsulation format of the forwarding label F-tag specified by the IEEE 802.1Qbp project. As shown in Figure 2, the forwarding label F-tag includes a 16-bit Tag Protocol ID (TPID for short), a 3-bit Priority Code Point (PCP for short), and a 1-bit discard flag (Drop Eligible, referred to as DE), 6-bit reserved field (Reserved Field, referred to as Rev), 6-bit time to live (Time To Live, referred to as TTL), and 16-bit flow identification (Flow ID). Among them, the 16-bit flow identifier is used to divide the traffic entering the network. Different flow identifiers correspond to different equivalent paths. Each specific flow identifier is used to select the equivalent multipath between the source node and the destination node. a specific path.

Through the above analysis, it can be found that the loopback detection function defined by the released IEEE 802.1ag standard is only applicable to the situation where there is only one Ethernet transmission path between the two maintenance points running this function, and it is not suitable for two maintenance points. There are equal cost multipaths between nodes. With the establishment of the IEEE 802.1Qbp standard project and the development of related standards, Ethernet will support the ECMP function. Therefore, the existing Ethernet OAM working mechanism needs to be expanded to support the Ethernet OAM requirements in the ECMP scenario.

Contents of the invention

The technical problem solved by the present invention is to provide a loopback detection method and system, which can realize the Ethernet OAM loopback detection function under the ECMP scene.

In order to solve the above-mentioned technical problems, the present invention provides a kind of loop detection method, is applied to the Ethernet that supports equal-cost multipath, and described method comprises:

The source maintenance end node sends a loopback message to the destination maintenance point, and the loopback message includes a flow identifier corresponding to a specific transmission path among multiple equivalent transmission paths to the destination maintenance point;

After the destination maintenance point receives the loopback message, it sends a loopback response message to the source maintenance end node, and the loopback response message includes information about the reverse common path transmission path to the source maintenance end node. the corresponding stream ID;

After the source maintenance end node receives the loopback response message and the detection is correct, it returns a notification that the loopback detection is successful.

Further, the source maintenance end node determines the flow identifier corresponding to the specific transmission path according to one or any combination of the following information input by the operator:

Flow identifier, equivalence tree algorithm identifier, source/destination media access control (MAC) address, source/destination IP address, source/destination port.

Further, after the destination maintenance point receives the loopback message, determines the specific transmission path according to the flow identifier contained therein, and calculates the flow identifier corresponding to the reverse common path transmission path, Send a loopback response message to the source maintenance end node, and include the flow identifier corresponding to the reverse common path transmission path in the loopback response message;

Wherein, the reverse shared transmission path means that the nodes passed by the reverse transmission path are exactly the same as the maintenance points passed by the forward transmission path.

Further, the source maintenance end node includes the flow identifier corresponding to the specific transmission path in the loopback message in the following manner:

The source maintenance end node carries a forwarding label in the loopback message, and the forwarding label includes a flow identifier corresponding to the specific transmission path.

Further, the source maintenance end node receives the loopback response message and detects it correctly, specifically including:

After the maintenance end node receives the loopback response message, it determines the transmission path of the loopback response message according to the flow identifier contained therein, and judges whether the transmission path is the same as the source maintenance end node sending the loopback message. The specific transmission path selected when returning the message is the same path, if yes, it is determined that the detection is correct, otherwise, it is determined that the detection fails, and a loopback detection failure notification is returned.

The present invention also provides a loopback detection system, which is applied to an Ethernet supporting equal-cost multipath, and the system includes: a transmission path determination unit in a source maintenance end node, a loopback message sending unit, and a loopback detection unit; the loopback response unit in the destination maintenance point,

The transmission path determination unit is configured to determine a specific transmission path from multiple equivalent transmission paths to the destination maintenance point;

The loopback message sending unit is configured to send a loopback message to a destination maintenance point, and the loopback message includes a flow identifier corresponding to the specific transmission path;

The loopback response unit is configured to, after receiving the loopback message, send a loopback response message to the source maintenance end node, where the loopback response message includes a reverse consensus to the source maintenance end node. The flow identifier corresponding to the transmission path;

The loopback detection unit is configured to return a notification that the loopback detection is successful after receiving the loopback response message and the detection is correct.

Further, the loopback message sending unit is further configured to determine the stream identifier corresponding to the specific transmission path according to one or any combination of the following information input by the operator, and include the loopback message in the loopback message The flow identifier corresponding to a specific transmission path:

Flow identifier, equivalence tree algorithm identifier, source/destination media access control (MAC) address, source/destination IP address, source/destination port.

Further, the loopback message sending unit is configured to include the flow identifier corresponding to the specific transmission path in the loopback message in the following manner:

A forwarding label is carried in the loopback message, and a flow identifier corresponding to the specific transmission path is included in the forwarding label.

Further, the loopback response unit is configured to, after receiving the loopback message, determine the specific transmission path according to the flow identifier contained therein, and calculate the After the flow identification, send a loopback response message to the source maintenance end node, and include the flow identification corresponding to the reverse common path transmission path in the loopback response message;

Wherein, the reverse shared transmission path means that the nodes passed by the reverse transmission path are exactly the same as the maintenance points passed by the forward transmission path.

Further, the loopback detection unit is configured to, after receiving the loopback response message, determine the transmission path of the loopback response message according to the flow identifier contained therein, and determine whether the transmission path is consistent with the source The specific transmission path selected by the maintenance end node when sending the loopback message is the same path, if yes, it determines that the detection is correct, otherwise, it determines that the detection fails, and returns a loopback detection failure notification.

The present invention expands the Ethernet loopback detection working mechanism stipulated in the IEEE 802.1ag standard, so that this function can be applied to the Ethernet supporting ECMP stipulated in the IEEE 802.1Qbp project, and performs loopback for a specific path among multiple equal-cost paths Detection, so as to support the application scenario of equal-cost multipath between two maintenance points.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Figure 1 is a schematic diagram of the loopback detection process specified in the IEEE 802.1ag standard;

Figure 2 is a diagram of the forwarding label F-tag encapsulation format specified by the IEEE 802.1Qbp project;

Fig. 3 is the overall schematic flow chart of the loopback detection method of the present invention;

4 is a schematic diagram of a loopback detection process in Embodiment 1 of the present invention;

FIG. 5 is a schematic diagram of a loopback detection process in Embodiment 2 of the present invention.

Detailed ways

The main purpose of the present invention is to provide a flow-based loopback detection mechanism in an Ethernet environment supporting ECMP. The basic idea is to propose a flow-based loopback detection mechanism by extending the loopback detection mechanism defined by the IEEE 802.1ag standard The loopback detection method can realize loopback detection for a specific transmission path in ECMP, and overcomes the problem in the prior art that there is no mechanism for loopback detection for a specific path in ECMP.

Specifically, a flow-based loopback detection method of the present invention adopts the following technical solution:

The maintenance end node sends a loopback message to the maintenance intermediate point or the peer maintenance end node, the loopback message carries the forwarding label F-tag, which includes a 16-bit flow identifier corresponding to the selected specific transmission path;

The destination maintenance point (the destination maintenance intermediate point or the destination maintenance end node) receives the loopback message carrying the F-tag, and sends a loopback response to the source end maintenance end node. The loopback response carries the forwarding label F-tag, which contains the corresponding The flow identifier for the reverse common path transmission path;

The source end maintenance end node receives the loopback response carrying the F-tag, checks the 16-bit stream identifier contained in it, and judges whether it corresponds to the reverse common path transmission path, as the basis for whether the loopback detection is successful.

Wherein, after the destination maintenance point receives the loopback message, it determines the selected specific transmission path according to the 16-bit flow identifier contained therein , and calculates the flow identifier corresponding to the reverse common path transmission path to the source end maintenance end node; Then the flow identifier on the reverse common path transmission path is included in the loopback response message sent to the source end maintenance point. The reverse shared transmission path means that the nodes passed by the reverse path are exactly the same as the nodes passed by the forward transmission path.

Based on the above thinking, the present invention proposes a flow-based loopback detection method, as shown in Figure 3, the method mainly includes:

Step 301: The maintenance end node determines the destination maintenance point according to the operator's input and selects one of multiple equivalent transmission paths to the destination maintenance point.

Here, the information input by the operator includes the identification of the destination maintenance point. Since the destination maintenance point is based on the switch port, its identification is generally the Media Access Control (MAC) address of the port where the destination maintenance point is located; the operator The input information also includes the identification of the specific path selected from the multiple equivalent transmission paths to the destination maintenance point. This identification can be a direct flow identification (Flow ID), or an indirect flow identification that can be calculated Other identifiers, including the Equal Cost Tree-Algorithm (ECT-Algorithm for short) identifier (from 00-80-C2-01 to 00-80-C2-10), or information parameters describing the flow (parameter set One or more of "source/destination MAC address, source/destination IP address, source/destination port").

Step 302: The maintenance end node sends a loopback message to the destination maintenance point, carrying the flow identifier corresponding to the selected transmission path.

According to the information input by the operator, the maintenance end node sends a loopback message to the destination maintenance point. The message is a unicast Ethernet frame. The destination MAC address is the MAC address of the switch port where the destination maintenance point is located, and the source MAC address is the switch where the maintenance end node is located. The MAC address of the port, and the message also carries the forwarding label F-tag, which includes the flow identifier corresponding to the selected transmission path.

Step 303: After receiving the loopback message, the destination maintenance point selects the reverse common path transmission path of the transmission path according to the flow identifier, and calculates the flow identifier corresponding to the reverse common path transmission path.

Specifically, after the destination maintenance point receives the loopback message sent by the maintenance end node, it checks the flow identifier carried in the loopback message, and judges which specific path the loopback message is transmitted along according to the identifier value. The specific judgment method A hash calculation may be performed on multiple parameters including the flow identifier, and the hash result corresponds to the selected specific transmission path. Then, the destination maintenance point calculates the flow identifier of the reverse common path transmission path corresponding to the specific transmission path. A possible calculation method is to perform anti-hash calculation according to the selected reverse common path transmission path.

Step 304: The destination maintenance point replies a loopback response message to the maintenance end node, carrying the calculated flow identifier corresponding to the reverse common path transmission path.

After the destination maintenance point calculates the flow identifier corresponding to the reverse common path transmission path, it replies a loopback response message to the maintenance end node. The message is a unicast Ethernet frame, and the destination MAC address is the MAC address of the switch port where the maintenance end node is located. The MAC address is the MAC address of the switch port where the destination maintenance point is located, and the message also carries a forwarding label F-tag, which includes a flow identifier corresponding to the reverse common path transmission path.

Step 305: After receiving the loopback response message, the maintenance end node detects the flow identifier to determine whether it corresponds to the reverse common path transmission path.

After receiving the loopback response message from the destination maintenance point, the maintenance end node checks the flow identifier carried in the loopback response message, and judges which specific path the loopback response message was transmitted along based on the identifier value, and determines the transmission path Whether it is on the same path as the transmission path selected when the maintenance end node sends the loopback message, and the judgment result is taken as a necessary condition for whether the loopback detection is successful.

In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined arbitrarily with each other.

Embodiment one

In this embodiment, the maintenance end node initiates loopback detection to the maintenance intermediate point.

FIG. 4 is a schematic diagram of a flow-based loopback detection process in this embodiment. As shown in Figure 3 and Figure 4, the process mainly includes the following steps:

Step 401: MEP1 determines the MIP according to the operator's input and selects one of the two equivalent transmission paths (SW1->SW21->SW3 and SW1->SW22->SW3) to reach the MIP.

The information entered by the operator includes the MAC address of the MIP, and also includes the identification of the specific path SW1->SW21->SW3 to the MIP. This identification can be a direct Flow ID1 or an indirect identification that can calculate the Flow ID1 , including ECT-Algorithm identification (from 00-80-C2-01 to 00-80-C2-10), or information parameters describing Flow (parameter set "source/destination MAC address, source/destination IP address, source/destination one or more of Destination Port").

Step 402: MEP1 sends a loopback message to MIP, carrying the flow identifier corresponding to the selected transmission path SW1->SW21->SW3.

According to the information input by the operator, MEP1 sends a flow-based loopback message to MIP. The message is a unicast Ethernet frame, the destination MAC address is the MAC address of MIP, the source MAC address is the MAC address of MEP1, and the message also carries a forwarding label. F-tag, which contains Flow ID1 corresponding to the selected transmission path SW1->SW21->SW3.

Step 403: After receiving the loopback message, the MIP selects the reverse common path transmission path of the transmission path according to the flow identifier, and calculates the flow identifier corresponding to the reverse common path transmission path.

After receiving the flow-based loopback message sent by MEP1, the MIP checks the flow ID carried in the loopback message, judges that the loopback message is transmitted along SW1->SW21->SW3 according to the ID value Flow ID1, and then calculates The flow identifier Flow ID2 corresponding to the reverse common path transmission path SW3->SW21->SW1 of the specific transmission path, Flow ID2 and Flow ID1 may be the same or different.

Step 404: MIP replies a loopback response message to MEP1, carrying the calculated flow identifier corresponding to the reverse common path transmission path.

MIP replies a flow-based loopback response message to MEP1. The message is a unicast Ethernet frame, the destination MAC address is the MAC address of MEP1, and the source MAC address is the MAC address of MIP. The message also carries the forwarding label F-tag, which contains Corresponds to Flow ID2 of the reverse common path SW3->SW21->SW1.

Step 405: After receiving the loopback response message, MEP1 detects the flow identifier to determine whether it corresponds to the reverse common path transmission path.

After receiving the flow-based loopback response message from the MIP, MEP1 checks the flow ID carried in the loopback response message, and judges that the loopback response message is transmitted along SW3->SW21->SW1 according to the ID value Flow ID2. It is in the same path as the transmission path SW1->SW21->SW3 selected when MEP1 sends the loopback message, and this judgment result is a necessary condition for the success of the loopback detection.

Embodiment two

In this embodiment, the maintenance end node initiates a loopback detection to the peer maintenance end node.

FIG. 5 is a schematic diagram of a flow-based loopback detection process in this embodiment. As shown in Figure 3 and Figure 5, the process mainly includes the following steps:

Step 501: MEP1 determines MEP2 according to the operator's input and selects one of the two equivalent transmission paths (SW1->SW21->SW3->SW4 and SW1->SW22->SW3->SW4) to reach MEP2.

The information entered by the operator includes the MAC address of MEP2, and also includes the identification of the specific path SW1->SW22->SW3->SW4 to MEP2. The identification can be a direct Flow ID3 or an indirect Flow ID3 that can be calculated. Other identifications, including ECT-Algorithm identification (from 00-80-C2-01 to 00-80-C2-10), or information parameters describing Flow (parameter set "source/destination MAC address, source/destination IP address , Source/Destination Port" or one or more).

Step 502: MEP1 sends a loopback message to MEP2, carrying the flow identifier corresponding to the selected transmission path SW1->SW22->SW3->SW4.

According to the information input by the operator, MEP1 sends a flow-based loopback message to MEP2. The message is a unicast Ethernet frame, the destination MAC address is the MAC address of MEP2, the source MAC address is the MAC address of MEP1, and the message also carries a forwarding label. F-tag, which contains Flow ID3 corresponding to the selected transmission path SW1->SW22->SW3->SW4.

Step 503: After receiving the loopback message, MEP2 selects the reverse common path transmission path of the transmission path according to the flow identifier, and calculates the flow identifier corresponding to the reverse common path transmission path.

After receiving the flow-based loopback message sent by MEP1, MEP2 checks the flow ID carried in the loopback message, and judges that the loopback message is transmitted along SW1->SW22->SW3->SW4 according to the ID value Flow ID3. Then calculate the flow identifier Flow ID4 of the reverse common path transmission path SW4->SW3->SW22->SW1 corresponding to the specific transmission path. Flow ID4 and Flow ID3 may be the same or different.

Step 504: MEP2 replies a loopback response message to MEP1, carrying the calculated flow identifier corresponding to the reverse common path transmission path.

MEP2 replies a flow-based loopback response message to MEP1. The message is a unicast Ethernet frame, the destination MAC address is the MAC address of MEP1, and the source MAC address is the MAC address of MEP2. The message also carries the forwarding label F-tag, which contains Corresponds to Flow ID4 of the reverse common path SW4->SW3->SW22->SW1.

Step 505: After receiving the loopback response message, MEP1 detects the flow identifier to determine whether it corresponds to the reverse common path transmission path.

After receiving the flow-based loopback response message from MEP2, MEP1 checks the flow identifier carried in the loopback response message, and judges that the loopback response message is transmitted along SW4->SW3->SW22->SW1 according to the identifier value Flow ID4 The incoming ones share the same path as the transmission path SW1->SW22->SW3->SW4 selected when MEP1 sends the loopback message. This judgment result is a necessary condition for the success of the loopback detection.

In addition, an embodiment of the present invention also provides a loopback detection system, which is applied to an Ethernet supporting equal-cost multipath. The system mainly includes: a transmission path determination unit in a source maintenance end node, a loopback message sending unit, and A loopback detection unit; a loopback response unit in the destination maintenance point,

The transmission path determination unit is used to determine a specific transmission path from multiple equivalent transmission paths to the destination maintenance point;

The loopback message sending unit is used to send a loopback message to the destination maintenance point, and the loopback message includes a flow identifier corresponding to a specific transmission path;

The loopback response unit is used to send a loopback response message to the source maintenance end node after receiving the loopback message, and the loopback response message includes the flow identifier corresponding to the reverse common path transmission path to the source maintenance end node;

The loopback detection unit is configured to return a notification that the loopback detection is successful after receiving the loopback response message and the detection is correct.

Further, the loopback message sending unit is further configured to determine the flow identifier corresponding to the specific transmission path according to one or any combination of the following information input by the operator, and include the flow identifier corresponding to the specific transmission path in the loopback message:

Flow identifier, equivalence tree algorithm identifier, source/destination media access control (MAC) address, source/destination IP address, source/destination port.

Further, the loopback message sending unit is configured to include the flow identifier corresponding to the specific transmission path in the loopback message in the following manner:

The forwarding label is carried in the loopback message, and the flow identifier corresponding to the specific transmission path is included in the forwarding label.

Further, the loopback response unit is configured to, after receiving the loopback message, determine a specific transmission path according to the flow identifier contained therein, and after calculating the flow identifier corresponding to the reverse common path transmission path, send the message to the source maintenance end node A loopback response message, and the loopback response message includes the flow identifier corresponding to the reverse common path transmission path;

Wherein, the reverse common path transmission path means that the nodes passed by the reverse transmission path are completely consistent with the maintenance points passed by the forward transmission path.

Further, the loopback detection unit is used to, after receiving the loopback response message, determine the transmission path of the loopback response message according to the flow identifier contained therein, and determine whether the transmission path is the one selected when the source maintenance node sends the loopback message. If the specific transmission path is common, it is determined that the detection is correct; otherwise, it is determined that the detection fails, and a loopback detection failure notification is returned.

The above are only preferred implementation examples of the present invention, and are not intended to limit the present invention. The present invention can also have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can Various corresponding changes and modifications are made in the present invention, but these corresponding changes and modifications should all belong to the protection scope of the appended claims of the present invention.

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned present invention can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed in a network formed by multiple computing devices Alternatively, they may be implemented in program code executable by a computing device so that they may be stored in a storage device to be executed by a computing device, and in some cases in an order different from that shown here The steps shown or described are carried out, or they are separately fabricated into individual integrated circuit modules, or multiple modules or steps among them are fabricated into a single integrated circuit module for implementation. As such, the present invention is not limited to any specific combination of hardware and software.

Claims (10)

1. a loopback detection method, is characterized in that, is applied to the Ethernet that supports equal-cost multipath, and described method comprises: The source maintenance end node sends a loopback message to the destination maintenance point, and the loopback message includes a flow identifier corresponding to a specific transmission path among multiple equivalent transmission paths to the destination maintenance point; After the destination maintenance point receives the loopback message, it sends a loopback response message to the source maintenance end node, and the loopback response message includes information about the reverse common path transmission path to the source maintenance end node. the corresponding flow ID; After the source maintenance end node receives the loopback response message and the detection is correct, it returns a notification that the loopback detection is successful. 2. The method of claim 1, wherein The source maintenance end node determines the flow identifier corresponding to the specific transmission path according to one or any combination of the following information input by the operator: Flow identifier, equivalence tree algorithm identifier, source/destination media access control (MAC) address, source/destination IP address, source/destination port. 3. The method of claim 1 or 2, wherein, After receiving the loopback message, the destination maintenance point determines the specific transmission path according to the flow identifier contained therein, calculates the flow identifier corresponding to the reverse common path transmission path, and sends the The source maintenance end node sends a loopback response message, and includes the flow identifier corresponding to the reverse common path transmission path in the loopback response message; Wherein, the reverse shared transmission path means that the nodes passed by the reverse transmission path are exactly the same as the maintenance points passed by the forward transmission path. 4. The method of claim 1, wherein, The source maintenance end node includes the flow identifier corresponding to the specific transmission path in the loopback message in the following manner: The source maintenance end node carries a forwarding label in the loopback message, and the forwarding label includes a flow identifier corresponding to the specific transmission path. 5. The method of claim 3, wherein, The source maintenance end node receives the loopback response message and detects it correctly, including: After the maintenance end node receives the loopback response message, it determines the transmission path of the loopback response message according to the flow identifier contained therein, and judges whether the transmission path is the same as the source maintenance end node sending the loopback message. The specific transmission path selected when returning the message is the same path, if yes, it is determined that the detection is correct, otherwise, it is determined that the detection fails, and a loopback detection failure notification is returned. 6. A loopback detection system, characterized in that it is applied to Ethernet supporting equal-cost multipath, said system comprising: a transmission path determination unit, a loopback message sending unit and a loopback detection unit in the source maintenance terminal node ;The loopback response unit in the destination maintenance point, The transmission path determination unit is configured to determine a specific transmission path from multiple equivalent transmission paths to the destination maintenance point; The loopback message sending unit is configured to send a loopback message to a destination maintenance point, and the loopback message includes a flow identifier corresponding to the specific transmission path; The loopback response unit is configured to, after receiving the loopback message, send a loopback response message to the source maintenance end node, where the loopback response message includes a reverse consensus to the source maintenance end node. The flow identifier corresponding to the transmission path; The loopback detection unit is configured to return a notification that the loopback detection is successful after receiving the loopback response message and the detection is correct. 7. The system of claim 6, wherein: The loopback message sending unit is further configured to determine the flow identifier corresponding to the specific transmission path according to one or any combination of the following information input by the operator, and include the specific transmission path in the loopback message Corresponding stream ID: Flow identifier, equivalence tree algorithm identifier, source/destination media access control (MAC) address, source/destination IP address, source/destination port. 8. The system of claim 6 or 7, wherein: The loopback message sending unit is configured to include the flow identifier corresponding to the specific transmission path in the loopback message in the following manner: A forwarding label is carried in the loopback message, and a flow identifier corresponding to the specific transmission path is included in the forwarding label. 9. The system of claim 6 or 7, wherein The loopback response unit is configured to, after receiving the loopback message, determine the specific transmission path according to the flow identifier contained therein, and calculate the flow identifier corresponding to the reverse common path transmission path , sending a loopback response message to the source maintenance end node, and including the flow identifier corresponding to the reverse common path transmission path in the loopback response message; Wherein, the reverse shared transmission path means that the nodes passed by the reverse transmission path are exactly the same as the maintenance points passed by the forward transmission path. 10. The system of claim 9, wherein: The loopback detection unit is used to, after receiving the loopback response message, determine the transmission path of the loopback response message according to the flow identifier contained therein, and determine whether the transmission path is consistent with the source maintenance end node The specific transmission path selected when sending the loopback message is the same path, if yes, it is determined that the detection is correct, otherwise, it is determined that the detection fails, and a loopback detection failure notification is returned.

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