WO2021143524A1

WO2021143524A1 - Fault detection method, and apparatus

Info

Publication number: WO2021143524A1
Application number: PCT/CN2020/141140
Authority: WO
Inventors: 侯大威; 邓建玺; 李帅; 王彬; 王明谱
Original assignee: 华为技术有限公司
Priority date: 2020-01-15
Filing date: 2020-12-30
Publication date: 2021-07-22
Also published as: CN113132223A

Abstract

Embodiments of the present application disclose a fault detection method and an apparatus. The method comprises: a source node of a first LSP under test sending, via the first LSP, a first packet to a destination node, the first packet carrying path information of the first LSP, and the first LSP comprising multiple sequentially arranged LSRs; the destination node establishing, after receiving the first packet and according to the path information, a second LSP having a direction which is the reverse of that of the first LSP and sharing a common path with the first LSP; and accordingly, the destination node feeding back a first BFD packet to the source node via the second LSP having the reverse direction to and sharing the common path with the first LSP, such that the source node determines a fault condition of the first LSP on the basis of the first BFD packet. In this way, the invention enables a destination node to establish, on the basis of path information, an LSP having a direction which is the reverse of that of an LSP under test and sharing a common path with the LSP under test, and accordingly enables common path transmission of a forward BFD packet and a reverse BFD packet in BFD testing, thereby achieving fast and accurate fault detection of LSPs.

Description

A fault detection method and equipment

This application claims the priority of a Chinese patent application filed with the State Intellectual Property Office of China, the application number is 202010043122.4, and the application name is "a fault detection method and equipment" on January 15, 2020. The entire content is incorporated herein by reference. Applying.

Technical field

This application relates to the field of communication technology, and in particular to a fault detection method and device used in the label switching path (English: Control Route Label Switched Path, abbreviation: Control Route Label Switched Path, abbreviation: In the CR-LSP scenario, a bidirectional link detection (English: Bidirectional Forwarding Detection, referred to as BFD) mechanism is used to detect whether there is a fault on the LSP.

Background technique

In Multiprotocol Label Switching (English: Multiprotocol Label Switching, MPLS for short) TE, the tunnel may include multiple CR-LSPs from a source node (English: Ingress) to a destination node (English: Egress). In order to ensure that the CR-LSP can safely and reliably transmit service streams, BFD, a mechanism that can quickly perform end-to-end detection, is usually used to detect whether the CR-LSP is faulty.

At present, the process of detecting CR-LSP in the BFD mechanism includes: Ingress sends forward detection packets to Egress through LSP, and requires Egress to feed back reverse detection packets to Ingress, so as to determine whether the LSP is faulty. Since the LSP is a one-way path, the reverse detection message can only be determined by the Internet Protocol (English: Internet Protocol, referred to as: IP) routing method to determine its transmission path, and the IP path determined by the IP routing method is probably not After each label switching node in the LSP (English: Label Switching Router, LSR for short), that is, the forward detection packet and the reverse detection packet do not share the same path. In this way, the detection result reflects the determination of the LSP and the IP routing method The overall failure of the IP path cannot accurately reflect whether the LSP fails.

Based on this, it is urgent to provide a fault detection method that not only uses the feature of the BFD mechanism to quickly complete the detection, but also overcomes the bidirectionality of the BFD mechanism and the conflict of one-way LSPs, and achieves more accurate fault detection for LSPs.

Summary of the invention

Based on this, the embodiments of the present application provide a fault detection method and device. By establishing a reverse LSP co-path with the LSP to be detected on the destination node side, the bidirectionality of the BFD mechanism and the conflict of the unidirectional LSP are overcome, and optimization is achieved. The BFD mechanism can perform more accurate fault detection on LSPs.

In the first aspect, the embodiments of the present application provide a fault detection method, which is applied to the first network device of the first LSP to be detected in the CR-LSP scenario (that is, the destination node of the first LSP). The fault detection process can be It includes: the second network device (ie, the source node of the first LSP) sends a first packet to the first network device via the first LSP, wherein the first packet carries path information of the first LSP, and The first LSP includes multiple LSRs arranged in sequence; then, after the first network device receives the first message, it can establish a second LSP from the first network device to the second network device according to the path information. The LSRs included in the two LSPs are the same as the LSRs included in the first LSP, and the sequence of multiple LSRs in the second LSP is opposite to the sequence of the multiple LSRs in the first LSP; based on this, the first network device is The first BFD packet may be fed back to the second network device via the second LSP that is in the reverse common path, so that the second network device can determine the failure condition of the first LSP based on the first BFD packet.

It can be seen that in the embodiment of the present application, the source node informs the destination node of the path information of the LSP to be detected, and the destination node establishes an LSP that shares the reverse path with the LSP to be detected based on the path information, using the forward LSP and the established reverse LSP The common path feature makes it possible to transmit forward BFD packets and reverse BFD packets in the same path in BFD detection. The BFD detection result can accurately reflect the failure of the LSP to be detected, which overcomes the bidirectional and unidirectional BFD mechanism. LSP conflicts, that is, the current BFD detection of forward BFD packets and reverse BFD packets are likely to not share the same path, causing the detection result to fail to accurately reflect the problem of LSP failures, and achieve faster and more accurate fault detection for LSPs.

Among them, the first message may be, for example, an LSP-Ping message, specifically an LSP-Ping request message. Then, the path information of the first LSP may use the extended type length value (English: Type Length) in the LSP-Ping message. Value (abbreviated as: TLV) field carried. The path information of the first LSP may be, for example, the IP address of each label switching node (English: Label Switched Router, LSR for short) through which the first LSP passes. In this way, the first network device receives the first packet carrying the path information of the first LSP, which is equivalent to obtaining the basis for establishing the second LSP that is in the reverse direction with the first LSP, so that the first network device establishes the second LSP. LSP becomes possible.

It is understandable that the second network device can also send a second BFD packet to the first network device through the first LSP to meet the characteristics of the two-way detection of the BFD mechanism, and the first network device can also receive the second BFD packet according to whether it can receive the second BFD packet. The second BFD packet sent by the network device via the first LSP determines the fault condition of the first LSP.

In some possible implementation manners, the embodiment of the present application may also determine at the first network device whether it has the ability to establish a second LSP, and inform the source node of the first LSP (ie, the second network device) of the capability. , So that the second network device determines its specific strategy for fault detection.

As an example, if the first network device determines that it has the ability to establish a second LSP, the first network device can not only apply for and cooperate with the second network device to establish the second LSP, but also send the second LSP to the second network device. A message, the second message carries capability information, and the capability information is used to characterize that the first network device has the ability to establish a second LSP. Then, the second network device can determine that the BFD mechanism is used for fault detection, that is, based on the first LSP and the second LSP, the first network device and the second network device negotiate the configuration parameters of BFD; According to the configuration parameters, the second network device sends a BFD packet to the first network device via the first LSP. After receiving the BFD packet via the first LSP, the first network device also sends the BFD packet based on the configuration parameters determined through negotiation. The second network device feeds back the response message. In this way, the BFD mechanism provided by the embodiment of the present application can realize rapid and accurate fault detection of the first LSP.

As another example, if the first network device determines that it does not have the ability to establish a second LSP, after the first network device receives the first packet sent by the second network device through the first LSP to be detected, the first network device The network device may not perform the process of applying and cooperating with the second network device to establish the second LSP, but may send the second packet to the second network device by way of IP routing, the capability information carried in the second packet, It is used to characterize that the first network device does not have the ability to establish a second LSP; or, after the first network device receives the first packet sent by the second network device through the first LSP to be detected, the second network device may not The first message is sent in response, and the second network device can also determine that the first network device does not have the ability to establish a second LSP when it does not get a response regarding the first message. Then, the second network device can choose not to use the BFD mechanism to perform fault detection on the first LSP, or, if it can tolerate the error in the detection result obtained by the current BFD mechanism to detect CR-LSP, it can also choose to use the current BFD mechanism to perform fault detection on the first LSP. An LSP performs fault detection. In this way, the method provided in the embodiments of the present application can allow the source node to perceive the ability of the destination node to establish the second LSP, so that the source node can configure its mechanism to detect the failure of the first LSP according to requirements, thereby achieving more flexibility for the first LSP Fault detection.

In the second aspect, the embodiments of the present application also provide a fault detection method, which is applied to the second network device of the first LSP to be detected in the CR-LSP scenario (ie, the source node of the first LSP), and the process of fault detection It may include: the second network device sends a first packet to the first network device (that is, the destination node of the first LSP) through the first LSP to be detected, where the first packet carries path information of the first LSP , The first LSP includes a plurality of LSRs arranged in sequence; then, the second network device receives the first BFD packet sent by the first network device via the second LSP, where the second LSP is the second network device based on the received The path information is established, the second LSP includes the multiple LSRs, and the sequence of the multiple LSRs in the second LSP is opposite to the sequence of the multiple LSRs in the first LSP; then, the second network The device can then determine the detection result of the first LSP based on the first BFD packet.

It can be seen that in the embodiment of the present application, the source node informs the destination node of the path information of the LSP to be detected, and the destination node establishes an LSP that shares the reverse path with the LSP to be detected based on the path information, using the forward LSP and the established reverse LSP The common path feature makes the forward BFD packets and the reverse BFD packets share the same path in the BFD detection. The BFD detection results can accurately reflect the failure of the LSP to be detected, which overcomes the bidirectionality of the BFD mechanism and the conflict of unidirectional LSPs. That is, in the current BFD detection, the forward BFD packet and the reverse BFD packet are likely not to share the same path, resulting in the problem that the detection result cannot accurately reflect the LSP failure condition, and realizes the faster and more accurate failure detection of the LSP.

The first message may be, for example, an LSP-Ping message, specifically an LSP-Ping request message. Then, the path information of the first LSP may be carried by the extended TLV field in the LSP-Ping message. The path information of the first LSP may be, for example, the IP addresses of each LSR passed by the first LSP. In this way, the second network device sends the first packet carrying the path information of the first LSP, which is equivalent to providing the first network device with a basis for establishing a second LSP that shares the reverse path with the first LSP, so that the first network device It is possible to establish a second LSP.

In some possible implementation manners, the embodiment of the present application may also determine at the first network device whether it has the ability to establish a second LSP, and inform the source node of the first LSP (ie, the second network device) of the capability. , So that the second network device can determine its specific strategy for fault detection.

As an example, if the first network device determines that it has the ability to establish a second LSP, the second network device can not only cooperate with the first network device to establish the second LSP, but also receive the second report sent by the first network device. The second packet carries capability information, and the capability information is used to characterize that the first network device has the ability to establish a second LSP. Then, the second network device can determine that the BFD mechanism is used for fault detection, that is, based on the first LSP and the second LSP, the second network device and the first network device negotiate the BFD configuration parameters; and, based on all the negotiated parameters According to the configuration parameters, the second network device sends a BFD packet to the first network device via the first LSP. After receiving the BFD packet via the first LSP, the first network device also sends the BFD packet based on the configuration parameters determined through negotiation. The second network device feeds back the response message. In this way, the BFD mechanism provided by the embodiment of the present application can realize rapid and accurate fault detection of the first LSP.

As another example, if the first network device determines that it does not have the ability to establish a second LSP, then after the second network device sends the first packet to the first network device through the first LSP to be detected, the second network device The device does not need to cooperate with the first network device to establish the second LSP, then the second network device can choose not to use the BFD mechanism to detect the failure of the first LSP, or, if the current BFD mechanism can tolerate the detection obtained by the CR-LSP If the result is incorrect, you can also choose to use the current BFD mechanism to perform fault detection on the first LSP. In this way, the method provided in the embodiments of the present application can allow the source node to perceive the ability of the destination node to establish the second LSP, so that the source node can configure its mechanism to detect the failure of the first LSP according to requirements, thereby achieving more flexibility for the first LSP Fault detection.

In other possible implementation manners, the embodiment of the present application may further include: the second network device determines the detection result of the first LSP according to the response message.

As an example, as long as the second network device receives the response message corresponding to the BFD message before sending the next BFD message, it determines that the first LSP is not faulty; on the contrary, if the second network device is sending the next BFD message If the response packet corresponding to the BFD packet is not received at the time of writing, it is determined that the first LSP is faulty.

As another example, a preset duration (for example, 10 milliseconds) can also be set, and the preset duration can be used to indicate the maximum time allowed to elapse between sending a BFD message and receiving its corresponding response message. Then, If the second network device receives the response message corresponding to the BFD message within the preset period of time, it is determined that the first LSP is not faulty; on the contrary, if the second network device has not received the BFD message for the preset period of time after sending it The response packet corresponding to the BFD packet determines that the first LSP is faulty.

It is understandable that after determining that the first LSP is faulty, the second network device may also switch the traffic carried by the first LSP to the backup LSP of the first LSP to ensure the normal transmission of traffic in the network; and The second network device can also report an alarm message above, which is used to inform the control user that the first LSP has failed, so that the technicians can detect and repair it as soon as possible. After the first LSP is repaired, the second network device will restore the traffic from the backup. Switch back to the first LSP on the LSP. In this way, reasonable and effective management of CR-LSP is realized, for example: CR-LSP management in MPLS TE tunnel, so that traffic can be safely and reliably transmitted in the network.

In the third aspect, the embodiments of the present application also provide a fault detection method, which is applied to the first network device (that is, the destination node of the first LSP) of the first LSP to be detected in the CR-LSP scenario, and the fault detection process It may include: the second network device (that is, the source node of the first LSP) sends a first packet to the first network device via the first LSP, where the first packet carries path information of the first LSP, The first LSP includes a plurality of LSRs arranged in sequence; at this time, in one case, if the first network device determines that it has the ability to establish a reverse common path second LSP, it executes the establishment of the slave according to the received path information. The second LSP from the second network device to the first network device, so as to subsequently perform BFD detection between the first network device and the second network device based on the first LSP and the second LSP. In another case, if the first network device determines that it does not have the ability to establish a reverse common path second LSP, the first network device can send a second message to the second network device through IP routing to inform the first network device A network device does not have the ability to establish a second LSP, or the first network device does not reply. When the second network device does not receive a reply, it sends the first network device to the first network device every preset time period. Message, when the number of consecutively sending the first message reaches the preset number of times, it is determined that the first network device does not have the ability to establish a second LSP; in this way, the second network device determines that the first network device does not have the ability to establish a second LSP After the ability, you can choose to use the current BFD mechanism to detect the failure of the first LSP according to the actual detection requirements of the user, or choose to no longer use the BFD mechanism to detect the failure of the first LSP. It can be seen that, in the embodiment of the present application, the source node can perceive the destination node to establish the reverse common-path LSP capability, so that the source node can decide the specific method to be used in subsequent failure detection, thereby enabling the failure detection of the LSP in the CR-LSP scenario More flexible.

In the fourth aspect, the embodiments of the present application also provide a fault detection method, which is applied to the second network device of the first LSP to be detected in the CR-LSP scenario (ie, the source node of the first LSP), and the process of fault detection It may include: the second network device sends a first packet to the first network device (that is, the destination node of the first LSP) via the first LSP, where the first packet carries path information of the first LSP, The first LSP includes a plurality of LSRs arranged in sequence; in this case, in one case, the second network device cooperates with the first network device to establish a reverse common-path second LSP, then the first network device and the second network Between devices, BFD detection is performed based on the first LSP and the second LSP. In another case, if the second network device receives the second packet sent by the first network device, it informs the first network device that it does not have the ability to establish a reverse common path second LSP, or the second network device is in advance. Assuming that no reply to the first message is received for the duration, then the first message is sent to the first network device every preset duration. When the number of consecutively sending the first message reaches the preset number of times, the first message is determined The network device does not have the ability to establish the second LSP; in this way, after the second network device determines that the first network device does not have the ability to establish the second LSP, it can choose to use the current BFD mechanism to detect the first LSP according to the actual detection needs of the user. The failure condition of the LSP, or the option to no longer use the BFD mechanism to perform failure detection on the first LSP. It can be seen that, in the embodiment of the present application, by allowing the source node to perceive the ability of the destination node to establish a reverse common-path LSP, the source node can decide the specific method to be used in subsequent failure detection, thereby achieving a more flexible response to the LSP in the CR-LSP scenario. Fault detection.

In a fifth aspect, an embodiment of the present application also provides a first network device, which is applied to a label-switched path CR-LSP scenario of a constrained path. The first network device includes a receiving unit, a sending unit, and a processing unit. The receiving unit is configured to receive a first packet sent by the second network device through the first LSP to be detected, the first packet carries path information of the first LSP, and the source node of the first LSP is the first network device , The destination node of the first LSP is the second network device, and the first LSP includes a plurality of label switching node LSRs arranged in sequence. The processing unit is configured to establish a second LSP from the first network device to the second network device according to the path information. The second LSP includes multiple LSRs, and the sequence of the multiple LSRs in the second LSP is consistent with that of the multiple LSRs. The sequence in the first LSP is reversed. The sending unit is configured to send the first bidirectional link detection BFD packet to the second network device via the second LSP, so that the second network device determines the failure condition of the first LSP based on the first BFD packet.

In some possible implementation manners, the receiving unit in the first network device is further configured to receive the second BFD packet sent by the second network device via the first LSP.

In other possible implementation manners, the sending unit in the first network device is also used to send a second message to the second network device. The second message carries capability information, and the capability information is used to characterize the capability of the first network device. The ability to establish a second LSP.

In still other possible implementation manners, the processing unit in the first network device is further configured to, before sending the first bidirectional link detection BFD message to the second network device via the second LSP, based on the first LSP and the second The LSP negotiates BFD configuration parameters with the second network device; then, the sending unit is specifically configured to send the first BFD packet to the second network device via the second LSP based on the configuration parameters determined through the negotiation.

It can be understood that the first packet is an LSP-Ping packet, and the path information is carried by the extended type length value TLV field in the LSP-Ping packet.

It should be noted that the first network device provided by the fifth aspect is used to perform the related operations mentioned in the first aspect or the third aspect. For the specific implementation and the achieved effects, please refer to the first aspect and the third aspect. The relevant description of the three aspects will not be repeated here.

In a sixth aspect, the embodiments of the present application also provide a second network device, which is applied to a label-switched path CR-LSP scenario of a constrained path. The second network device includes a sending unit, a receiving unit, and a processing unit. The sending unit is configured to send a first packet to the first network device via the first LSP to be detected, the first packet carrying path information of the first LSP, and the source node of the first LSP is the second network device , The destination node is the first network device, and the first LSP includes a plurality of label switching node LSRs arranged in sequence. The receiving unit is configured to receive a first bidirectional link detection BFD message sent by the first network device via a second LSP, where the second LSP is established by the second network device based on path information, and the second LSP includes multiple LSRs, In addition, the sequence of the multiple LSRs in the second LSP is opposite to the sequence of the multiple LSRs in the first LSP. The processing unit is configured to determine the detection result of the first LSP based on the first BFD packet.

In some possible implementation manners, the sending unit in the second network device is further configured to send the second BFD packet to the first network device via the first LSP.

In other possible implementation manners, the receiving unit in the second network device is also used to receive a second packet sent by the first network device, the second packet carries capability information, and the capability information is used to characterize the first network device Have the ability to establish a second LSP.

In still other possible implementation manners, the processing unit in the second network device is further configured to, before receiving the first bidirectional link detection BFD message sent by the first network device via the second LSP, based on the first LSP and the first LSP The second LSP negotiates BFD configuration parameters with the first network device; then, the receiving unit is specifically configured to: receive the first BFD message sent by the first network device via the second LSP based on the negotiated configuration parameters.

In still other possible implementation manners, the processing unit in the second network device is further configured to switch the traffic carried on the first LSP to the third LSP if the detection result indicates that the first LSP is faulty. The source node is the second network device, and the destination node of the third LSP is the first network device.

It should be noted that the second network device provided by the sixth aspect is used to perform the related operations mentioned in the second aspect or the fourth aspect. For the specific implementation and the achieved effects, please refer to the second aspect and the first aspect. The description of the four aspects will not be repeated here.

In a seventh aspect, an embodiment of the present application also provides a first network device, including: a memory and a processor. Among them, the memory is used to store program codes or instructions; the processor is used to run the program codes or instructions, so that the device executes the method provided in the first aspect or the third aspect.

In an eighth aspect, an embodiment of the present application also provides a second network device, including: a memory and a processor. Among them, the memory is used to store program codes or instructions; the processor is used to run the program codes or instructions, so that the device executes the method provided in the above second or fourth aspect.

In the ninth aspect, the embodiments of the present application also provide a network system. The network system includes the first network device provided in the fifth aspect and the second network device provided in the sixth aspect; or, the network system may also include the seventh aspect Provide the first network device and the second network device provided in the eighth aspect.

In a tenth aspect, the embodiments of the present application also provide a computer-readable storage medium. The computer-readable storage medium stores program codes or instructions, which when run on a computer, cause the computer to execute the first and second aspects above. Aspect, the third aspect, or any one of the methods provided in the fourth aspect.

In the eleventh aspect, the embodiments of the present application also provide a computer program product. When the computer program product is run on a network device, the network device can execute the first aspect, the second aspect, the third aspect, or the fourth aspect. The method provided in any one of the possible implementations.

Description of the drawings

FIG. 1 is a schematic diagram of a network system framework involved in an application scenario in an embodiment of this application;

Figure 2 is a signaling flow chart of a method for detecting LSP 1 in an embodiment of this application;

FIG. 3 is a signaling flowchart of another method for detecting LSP 1 in an embodiment of this application;

FIG. 4 is a signaling flowchart of a fault detection method 100 in an embodiment of the application;

FIG. 5 is a schematic diagram of a format of a first message in an embodiment of this application;

FIG. 6a is a schematic diagram of the format of a TLV extended by a first message in an embodiment of this application;

FIG. 6b is a schematic diagram of the format of another TLV extended by the first message in an embodiment of this application;

FIG. 7 is a schematic structural diagram of a first network device 700 in an embodiment of this application;

FIG. 8 is a schematic structural diagram of a second network device 800 in an embodiment of this application;

FIG. 9 is a schematic structural diagram of another first network device 900 in an embodiment of this application;

FIG. 10 is a schematic structural diagram of another second network device 1000 in an embodiment of this application;

FIG. 11 is a schematic structural diagram of a network system 1100 in an embodiment of this application.

Detailed ways

An MPLS TE tunnel usually includes multiple LSPs with the same source node and destination node. In order to ensure that the MPLS TE tunnel can effectively transmit service streams, it is necessary to perform fault detection on the LSPs and switch the service streams carried on the failed LSP. To other fault-free LSPs, the service flow can be effectively transmitted on the fault-free LSPs. BFD is an end-to-end detection mechanism for quickly sending and receiving packets. It can quickly send BFD packets and receive BFD packets from the opposite end, and determine the fault condition of the link through which forward BFD packets and reverse BFD packets pass. . Since the BFD mechanism can realize the sending and receiving of BFD packets in milliseconds between the source node and the destination node, the BFD mechanism can meet the fast requirements for LSP fault detection in the MPLS TE tunnel.

Currently, the process of using the BFD mechanism to detect LSP failures can include: the source node sends forward BFD packets to the destination node through the LSP to be detected, and the destination node sends reverse BFD packets to the source node through IP routing. , The source node determines whether the LSP is faulty based on the received reverse BFD packet. Since the LSP is a unidirectional constrained path, the IP path determined by the IP routing method may not be exactly the same as the LSR of the label switching node that the LSP passes through. In this way, the detection result reflects the IP path determined by the LSP and the IP routing method. The overall failure situation, rather than just reflecting whether the LSP has failed.

For example: Take the MPLS TE scenario shown in Figure 1 as an example. This scenario includes network equipment 110, network equipment 120, network equipment 130, network equipment 140, and network equipment 150, where LSP 1 passes through: network equipment 110-> Network equipment 120->network equipment 130; LSP 2 goes through in sequence: network equipment 110->network equipment 150->network equipment 140->network equipment 130. Then, as shown in FIG. 2, in the scenario shown in FIG. 1, the process of performing fault detection on the LSP 1 may specifically include: S11, the network device 110 sends a BFD message 1 to the network device 130 through the LSP 1; S12, Based on the IP routing method, the network device 130 sends the BFD message 2 to the network device 110 through the IP path 1, where the IP path 1 passes through the network device 130->network device 140->network device 150->network device 110 in turn; S13, The network device 110 determines the detection result according to the BFD message 2; S14, if the detection result indicates a failure, it switches the traffic carried on the LSP 1 to the LSP 2. It should be noted that the detection result indicates the failure, which may be caused by the failure of the network equipment or link that LSP 1 passes through, or the link or network equipment that IP path 1 passes through. If IP path 1 passes through the link Or network equipment failure. Since all LSRs included in IP path 1 and LSP 2 are the same, LSP 2 is likely to fail. Then, after S14 is executed, it is likely that traffic will be switched from the normal LSP 1 to the failed LSP 2 by mistake. Therefore, the traffic cannot be effectively transmitted in the MPLS TE tunnel.

Based on this, in the embodiment of the present application, a fault detection method is provided, which is applied in a CR-LSP scenario. For the first LSP to be detected, the source node informs the destination node of the path information of the first LSP to be detected , The destination node establishes a second LSP that is in the reverse direction with the first LSP to be detected based on the path information, so that the reverse BFD packet in the BFD detection can pass through the second LSP and the forward BFD packet in the reverse direction. The transmission of the first LSP overcomes the conflict between the bidirectionality of the BFD mechanism and the unidirectionality of the LSP. That is, in the current BFD detection, the BFD message and the response message are likely to not share the same path, which causes the detection result to fail to accurately reflect the LSP failure situation. Problem, to achieve faster and more accurate fault detection for LSP.

For example, still taking the scenario shown in FIG. 1 as an example, in the embodiment of the present application, referring to FIG. 3, the specific fault detection process may include: S21, the network device 110 sends an LSP-Ping to the network device 130 through the LSP 1 Message, the LSP-Ping message carries path information of LSP 1, for example: the IP address list of each node included in LSP 1, as shown in Figure 1, on the link from network device 110 to network device 120 The IP address corresponding to the device 110 is IP 1, and the IP address corresponding to the network device 120 on the link from the network device 120 to the network device 130 is IP 3. Then, the path information of the LSP 1 includes: IP 1 and IP 3; S22, The network device 130 establishes an LSP 1'according to the path information of the LSP 1, and the LSP 1'passes through: network device 130->network device 120->network device 110, as shown in Figure 1, from network device 130 to network device 120 The IP address corresponding to the network device 130 on the link is IP 4, and the IP address corresponding to the network device 120 on the link from the network device 120 to the network device 110 is IP 2. Then, the path information of the LSP 1'can include: IP 4 and IP 2; S23, the network device 110 and the network device 130 negotiate to determine the configuration parameters of BFD, for example: BFD detection period; S24, the network device 110 sends a BFD packet to the network device 130 through the LSP 1 based on the configuration parameters determined by the negotiation 1; S25, the network device 130 sends a BFD packet 2 to the network device 110 via the LSP 1'based on the configuration parameters; S26, the network device 110 determines the detection result of the LSP 1 based on the BFD packet 2. In this way, the network device 110 informs the network device 130 of the path information of the LSP 1, and the network device 130 can establish an LSP 1'that shares the reverse path with the LSP 1 based on the path information, so that the BFD message and response message in the BFD detection can be Transmission is carried out through the reverse common-path LSP 1 and LSP 1'. After the same LSR, the detection result can accurately reflect the failure detection of LSP 1.

It is understandable that the foregoing scenario is only an example of a scenario provided in an embodiment of the present application, and the embodiment of the present application is not limited to this scenario.

It should be noted that, in the embodiments of this application, network equipment and nodes refer to the same meaning in this application, and can be used interchangeably. In the embodiment of the present application, the network device may specifically include, but is not limited to, a switch, a router, or a firewall.

It should be noted that, in this embodiment of the application, the LSP may be a CR-LSP determined between the source node and the destination node through constraints such as link costs or labels. The CR-LSP is a unidirectional path and includes multiple Orderly arranged label switching node LSR. Adjacent LSRs can be directly connected or connected through a transit node. In the embodiment of this application, for the LSP to be detected and the established LSP in the reverse direction, only the LSRs included in it are concerned. Including transit nodes and whether the transit nodes are consistent will not be considered.

It is understandable that, in the embodiment of the present application, two LSPs are in the reverse common path, which means that all LSRs included in the two LSPs are the same, and the order of the LSRs in one LSP is opposite to the order of the LSRs in the other LSP. For example: the source node in an LSP is the destination node of another LSP, the destination node in an LSP is the source node of another LSP, the second LSR in an LSP is the penultimate LSR of another LSP, and so on .

The specific implementation of a fault detection method in the embodiment of the present application will be described in detail below with reference to the accompanying drawings and embodiments.

FIG. 4 is a signaling flowchart of a fault detection method 100 in an embodiment of the application. Referring to FIG. 4, the method 100 is applied in a CR-LSP scenario, and the embodiment of the present application is introduced with the interaction between the source node and the destination node of the first LSP to be detected. The method 100 may be applied to the network scenario shown in FIG. 1, for example, in an example, the method 100 may be to perform fault detection on the LSP 1 from the network device 110 to the network device 130, where LSP 1 and LSP 1'respectively correspond to The first LSP and the second LSP in the method 100, the network device 110 and the network device 130 respectively correspond to the second network device and the first network device in the method 100; as another example, the method 100 can also be used for the network device 130 Perform fault detection on the LSP 1'of the network device 110, where LSP 1'and LSP 1 respectively correspond to the first LSP and the second LSP in the method 100, and the network device 130 and the network device 110 respectively correspond to the first LSP in the method 100. The second network device and the first network device.

During specific implementation, the method 100 may include the following S101 to S108, for example:

S101: The second network device sends a first packet to the first network device via the first LSP to be detected, where the first packet carries path information of the first LSP, and the source node of the first LSP is the second network device, The destination node of the first LSP is the first network device, and the first LSP includes multiple LSRs arranged in sequence.

S102: The first network device receives a first packet sent by the second network device through the first LSP to be detected.

The first LSP refers to the LSP created by the second network device from the second network device to the first network device. The first LSP may include multiple LSRs. For the created first LSP, the positions of the multiple LSRs in the first LSP are fixed, that is, the first LSP includes multiple LSRs arranged in sequence. For example, assuming that the first LSP is LSP 1 in the scenario shown in FIG. 1, the first LSP includes a plurality of LSRs arranged in sequence, namely: network device 110, network device 120, and network device 130. In addition to the source node (ie, the second network device) and the destination node (ie, the first network device) of the first LSP, the multiple LSRs of the first LSP may also include at least one other LSR, such as: Among the multiple LSRs, the source node is the network device 110, the destination node is the network device 130, and other LSRs only include the network device 120.

As an example, before performing S101, the embodiment of the present application may further include: S31, the second network device applies to establish a CR-LSP from the second network device to the first network device, and establishes the CR-LSP through cooperation with the first network device The first LSP, and save the path information of the first LSP; S32, if the first LSP needs to be detected for failure, the second network device can enable BFD to trigger the establishment of a BFD session, for example: through configuration commands To enable the BFD capability on the second network device.

The path information is used to indicate the LSR experienced by the first LSP and the sequence in which each LSR appears in the first LSP. For example, the path information of the first LSP may be an IP address list composed of the IP addresses of each hop LSR, each The position of the IP address in the IP address list matches the position of the LSR corresponding to the IP address in the first LSP. Assuming that the first LSP is the LSP 1 in the scenario shown in FIG. 1, and the IP address of the network device 110 is IP 1, the IP address of the network device 120 is IP 2, and the IP address of the network device 130 is IP 3. Then, the first The path information of an LSP is as follows: IP 1, IP 2, and IP 3.

In specific implementation, after the above S32 is executed, the second network device can generate a first message based on the configuration information, and send the first message to the first network device to inform the first network device of the first message to be detected. The path information of an LSP provides a data basis for the first network device to establish a second LSP that is in the reverse direction with the first LSP in the subsequent S103.

As an example, the first message may be an LSP-Ping message. The specific format is shown in Figure 5, and it may specifically include a version number (English: Version Number) field, which is used to identify the version number of the MPLS command, for example: The version number field can be 1; the zero (English: Must Be Zero) field must be filled with all 0s, and this field can be ignored when the message is received; the message type (English: Message Type) field is used to identify the MPLS command The type of the message, for example: when Message Type=1, it indicates that the LSP-Ping message is a request message; when Message Type=2, it indicates that the LSP-Ping message is a response message; the reply mode (English: Reply Mode) field, It is used to indicate the reply mode adopted by the node receiving the message. For example, when Reply Mode=1, it means that no reply is required. When Reply Mode=2, it means that the fourth version of the Internet Protocol (English: Internet Protocol version 4, abbreviated as: IPv4) User Datagram Protocol (English: User Datagram Protocol, abbreviated as: UDP) data packet to reply, when Reply Mode=3, it means that the reply is made through the IPv4UDP data packet with router alarm; the return code (English: Return Code) field , The sending end can set the value of this field to 0, and the receiving end can set the value of this field to 0-7. The specific value and the meaning of the characterization can be flexibly set according to requirements, and will not be repeated here; return subcode ( English: Return Subcode) field, a pointer used to identify the end of the processing of the label stack, for example: when Return Subcode = 0, it means that the message does not carry a label and does not need to process the label. When Return Subcode takes other values, it represents the message Carries a label; the sender handle (English: Sender's Handle) field is used to identify a specific MPLS command, and its value can be randomly generated when an MPLS command request is sent; the sequence number (English: Sequence Number) field, the same Used to identify a specific MPLS command, valid in a process; the timestamp (English: Timestamp) field, specifically can use the time format defined by the Network Time Protocol (English: Network Time Protocol, abbreviated as: NTP), which can specifically include the sending time (For example: the field corresponding to the second and the field corresponding to the millisecond) and the receiving time (for example: the field corresponding to the second and the field corresponding to the millisecond); reserved area, the reserved area can be extended with multiple type length values (English: Type Length Value (abbreviation: TLV) field.

In the embodiment of this application, the first message may specifically be the LSP-Ping request message in the LSP-Ping message, that is, in the LSP-Ping message format shown in FIG. 5, Message Type=1, Reply Mode=2, and extend the TLV field in the reserved area to carry path information corresponding to the first LSP. Still taking the LSP 1 shown in Figure 1 as the first LSP as an example, the path information of the first LSP is: IP 1 and IP 3 in order. In one case, the first packet can be extended in the LSP-Ping packet A TLV field carries path information. For example, the format of the extended TLV field can be seen in Figure 6a. In the extended TLV, Type can be 127, which is used to identify that the TLV field carries path information of LSP 1, and the value of Length is equal to the extended TLV. The length of the field; Value can include reserved fields, the number of addresses (English: Hop Num), and specific path information. Specifically, reserved fields can be filled with 0, Hop Num can be 2, and path information can include IP 1 and IP 3. In another case, the first message can also extend multiple TLV fields in the LSP-Ping message, and multiple TLV fields collectively carry the path information, and each TLV field carries an IP address in the path information. For another example, the format of the extended TLV field can be seen in Figure 6b. Two TLVs are extended: TLV 1 and TLV 2, where Type 1 in TLV 1 can be 127, which is used to identify that the TLV 1 field carries LSP Path information of 1, the value of Length 1 is equal to the length of the extended TLV 1 field; Value 1 can include reserved fields (all 0s can be filled in), Hop Num = 1, and IP 1; Type 2 in TLV 2 can be 127, It is used to identify that the TLV 2 field carries the path information of LSP 1, and the value of Length 2 is equal to the length of the extended TLV 2 field; Value 2 can include reserved fields (all 0s can be filled in), Hop Num = 1, and IP 3 . It should be noted that the format of the LSP-Ping message and the meaning of related fields can be found in RFC4379 entitled "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures" dated February 2006, all of which The content is incorporated here by citation, just like all statements, so I won’t repeat it here.

S103: The first network device establishes a second LSP from the first network device to the second network device according to the path information, the second LSP includes the multiple LSRs, and the arrangement of the multiple LSRs in the second LSP The sequence is opposite to the sequence of the multiple LSRs in the first LSP.

It is understandable that, after receiving the first packet carrying the path information of the first LSP, the first network device may first determine whether it has the first packet that carries the path information of the first LSP before performing the following S103. Second, if the LSP has the capability, S103 is executed; if not, S103 to S108 are not executed.

As an example, S103 may specifically include: the first network device determines, according to the path information, the LSRs that the second LSP that needs to be established in turn needs to pass through; the first network device cooperates with the second network device to create the second network device according to the determined LSR. LSP. The second LSP refers to an LSP that is in the reverse direction of the first LSP created by the first network device, and the source node of the second LSP is the first network device, and the destination node is the second network device. Taking LSP 1 shown in Figure 1 as the first LSP and LSP 1'as the second LSP as an example, the path information of the second LSP is: IP 4 and IP 2 in order.

In the embodiment of the present application, after S103, it may further include: the first network device may enable BFD to trigger the establishment of a backhaul BFD session, for example, the BFD capability on the first network device may be enabled through a configuration command.

In addition, in order to let the second network device know that the first network device has the ability to establish a second LSP that is in the reverse common path with the first LSP, the first network device may also send a second packet to the second network device. The second message carries capability information, which is used to characterize that the first network device has the ability to establish a second LSP. It should be noted that the timing for the first network device to send the second message to the second network device can be performed before S103, after S103, or simultaneously with S103, which will not be specified in this embodiment of the application. limited.

For example, the second message may specifically be the LSP-Ping response message in the LSP-Ping message, that is, in the LSP-Ping message format shown in FIG. 5, set Message Type=2 and Return Code=8( That is, it indicates that the first network device has received the path information of the first LSP and supports the establishment of an LSP that shares a reverse path with the first LSP).

It should be noted that if the first network device determines that it does not have the ability to create a second LSP that shares a reverse path with the first LSP, the first network device can perform different operations according to actual needs, for example: the first network The device may send a second packet to the second network device through IP routing. The second packet carries capability information, and the capability information is used to indicate that the first network device does not have the ability to establish a second LSP, then the second The network device can make specific decisions about fault detection. For example, the second message is specifically the LSP-Ping response message in the LSP-Ping message, that is, in the LSP-Ping message format shown in Figure 5, set Message Type=2, Return Code=2 (that is, it indicates that the first network device has received the path information of the first LSP but does not support the establishment of an LSP that shares a reverse path with the first LSP); another example: the first network device may be wrong Reply to the first message, then the second network device can set it to send the first message to the first network device at a preset time interval (for example: 1 second) before it starts to send the BFD message. When the number of first messages reaches the preset number (for example, 3 times), it is determined that the first network device does not have the ability to establish a second LSP.

When the second network device determines that the first network device does not have the ability to establish the second LSP, it can choose not to use the BFD mechanism that cannot accurately detect the failure to perform failure detection on the first LSP according to the actual failure detection requirements of the user; or, You can also choose to use the current BFD mechanism to detect the failure of the first LSP. Wherein, the current BFD mechanism for detecting the failure of the first LSP may include, for example: S41, the second network device sends an LSP-Ping request message to the first network device, which carries the identifier of the second network device; S42, A network device records the identifier of the second network device, carries both its own identifier and the identifier of the second network device in the LSP-Ping response message, and sends it to the second network device; S43, the second network device Record the identifier of the first network device; S44, the second network device negotiates with the first network device to determine BFD configuration parameters; S45, the second network device sends a forward BFD packet to the first network device through the first LSP; S46, the first network device sends a reverse BFD packet to the second network device via IP routing; S47, the second network device determines the fault condition of the first LSP according to the reverse BFD packet.

It should be noted that the unsuccessful establishment of the second LSP may be because the first network device does not support the establishment of the second LSP, or it may be due to other reasons, such as insufficient label resources. "The first network device does not have the ability to establish a second LSP" in the embodiments of the present application may mean that the first network device does not support the establishment of the second LSP, or it may refer to a situation where the establishment of the second LSP is unsuccessful due to other reasons.

It can be seen that in the embodiment of the present application, the source node can perceive the destination node to establish the reverse common-path LSP capability, so that the source node can decide the specific method used in subsequent failure detection, so that the failure of the LSP in the CR-LSP scenario Detection is more flexible.

It should be noted that, in the embodiment of the present application, a second LSP that is in the reverse direction of the first LSP to be detected is established, so that when the BFD mechanism is subsequently used to detect the first LSP, the response message of the BFD message and the BFD The message is transmitted through the reverse common-path LSP, thereby accurately detecting the failure of the first LSP, providing an indispensable data foundation.

S104: The second network device sends the first BFD packet to the first network device through the first LSP.

S105: The first network device receives the first BFD packet sent by the second network device via the first LSP.

S106: The first network device sends a second BFD packet to the second network device through the second LSP.

S107: The second network device receives the second BFD packet sent by the first network device via the second LSP.

S108: The second network device determines the detection result of the first LSP based on the second BFD packet.

It is understandable that, in the embodiment of the present application, the process of using the BFD mechanism to detect the failure of the LSP to be detected includes three parts: the first part is to establish an LSP that shares the reverse path with the LSP to be detected; the second part, The configuration parameters for sending and receiving BFD messages are determined through negotiation; the third part, based on the operation results of the first and second parts, performs fault detection on the LSP to be detected through the BFD message and its corresponding response message. Among them, the first part can correspond to the above S101 to S103, and the specific process implemented in the second part can be: between S103 and S104, based on the first LSP and the second LSP, the first network device and the second network device negotiate the configuration of BFD Parameters, the configuration parameters are used to standardize the parameters for subsequent execution of S104-S107, for example: the period of execution of S104 and S107 (for example: 10 seconds). The third part may be: the second network device sends a forward first BFD packet to the first network device via the first LSP based on the configuration parameters determined through negotiation; and the first network device receives the first BFD packet Then, based on the configuration parameters determined through negotiation, a second reverse BFD packet is sent to the second network device via the second LSP; the second network device receives the second BFD packet to determine the detection result of the first LSP.

For the second network device in S108 to determine the detection result of the first LSP based on the second BFD packet, the detection result may be determined according to a configuration parameter manually set or negotiated in advance. As an example, as long as the second network device receives the second BFD packet, it determines that the first LSP is not faulty; on the contrary, if the second network device does not receive the second BFD packet, it determines that the first LSP is faulty. As another example, a preset duration (for example: 30 milliseconds) can also be set, and the preset duration can be manually set, or it can be one of the configuration parameters determined through negotiation to indicate the first network device The longest period allowed to pass the second BFD packet, then, if the second network device receives the next second BFD packet within the preset time interval, it is determined that the first LSP is not faulty; on the contrary, if the second network device If the device does not receive the next second BFD packet within the preset interval, it determines that the first LSP is faulty. Among them, the specific value of the preset duration can be flexibly set according to the actual situation.

For example, in the scenario shown in Figure 1, S104-S108 may specifically include: network device 110 sends BFD packets 1 to network device 130 via LSP 1 every 10 milliseconds; network device 130 sends BFD packets 1 via LSP 1'every 20 milliseconds The network device 110 sends a BFD message 2. In one case, if the network device 110 receives the next BFD message 2 within 60 milliseconds (that is, 3 times of 20 milliseconds, and 3 is a preset multiple) after receiving a BFD message 2, then it determines LSP 1'is fault-free, thus confirming that the common LSP 1 is fault-free; if the network device 110 receives a BFD message 2 after 80 milliseconds before receiving the next BFD message 2, or, after receiving a BFD message If the next BFD message 2 is not received after message 2, it is determined that LSP 1'is faulty, and thus the common LSP 1 is faulty. In another case, if the network device 130 receives the next BFD message 1 within 40 milliseconds (that is, 4 times of 10 milliseconds, 4 being a preset multiple) after receiving a BFD message 1, then, Make sure that the LSP 1 is not faulty; if the network device 130 receives the next BFD packet 1 after 40 milliseconds after receiving a BFD packet 1, or it has not received the next BFD packet 1 Message 1, then it is determined that LSP 1 is faulty. Among them, 10 milliseconds, 20 milliseconds, multiple 3, and multiple 4 may all be the configuration parameters negotiated in the second part.

It should be noted that after determining that the first LSP is faulty, the second network device may also switch the traffic carried by the first LSP to the backup LSP of the first LSP to ensure the normal transmission of traffic in the network; and The second network device can also report an alarm message above, which is used to inform the control user that the first LSP has failed, so that the technicians can detect and repair it as soon as possible. After the first LSP is repaired, the second network device will restore the traffic from the backup. Switch back to the first LSP on the LSP.

In this way, in the embodiment of the present application, the source node can inform the destination node of the path information of the LSP to be detected, and the destination node establishes an LSP that shares the reverse path with the LSP to be detected based on the path information, so that the forward and reverse directions in the BFD detection BFD packets can be transmitted through a common LSP, which overcomes the current BFD mechanism for forward and reverse BFD packets using CR-LSP and IP routing respectively to determine the transmission path transmission, and the transmission determined by the two methods There is a high probability that the paths are not co-routed, resulting in the detection result reflecting the failure of the entire loop (that is, the transmission path determined by the IP routing method and the two parts of the CR-LSP), but cannot accurately reflect the failure of the unidirectional LSP to be detected The problem solves the conflict between the bidirectionality of the BFD mechanism and the unidirectionality of the LSP. It can be seen that the use of the BFD mechanism provided in the embodiments of this application to detect the failure of the LSP not only takes advantage of the feature that the BFD mechanism can quickly complete the detection, but also based on the construction of the reverse common path LSP makes the use of the BFD mechanism to detect the failure of the LSP more accurately . Moreover, the embodiment of the present application also allows the source node to perceive whether the destination node has the ability to establish a reverse common path LSP, so that the source node can decide the specific method to be used in subsequent failure detection, so as to prevent the failure of the LSP in the CR-LSP scenario. Detection is more flexible.

Correspondingly, an embodiment of the present application also provides a first network device 700, as shown in FIG. 7. The first network device 700 is applied to a label-switched path CR-LSP scenario where a path is restricted. The first network device 700 includes a receiving unit 701, a sending unit 702, and a processing unit 703.

The receiving unit 701 is configured to receive a first packet sent by the second network device through the first LSP to be detected, the first packet carrying path information of the first LSP, and the source node of the first LSP is the first network Device, the destination node of the first LSP is the second network device, and the first LSP includes a plurality of label switching node LSRs arranged in sequence.

The processing unit 703 is configured to establish a second LSP from the first network device to the second network device according to the path information. The second LSP includes multiple LSRs, and the arrangement order of the multiple LSRs in the second LSP is consistent with the multiple LSRs. The arrangement order in the first LSP is reversed.

The sending unit 702 is configured to send the first bidirectional link detection BFD packet to the second network device via the second LSP, so that the second network device determines the failure condition of the first LSP based on the first BFD packet.

In some implementation manners, the receiving unit 701 in the first network device 700 is further configured to receive the second BFD packet sent by the second network device via the first LSP.

In other implementations, the sending unit 702 in the first network device 700 is also used to send a second message to the second network device. The second message carries capability information, and the capability information is used to characterize the capability of the first network device. The ability to establish a second LSP.

In still other implementation manners, the processing unit 703 in the first network device 700 is further configured to, before sending the first bidirectional link detection BFD message to the second network device through the second LSP, based on the first LSP and the second The LSP negotiates BFD configuration parameters with the second network device; then, the sending unit 702 is specifically configured to send the first BFD packet to the second network device via the second LSP based on the configuration parameters determined through the negotiation.

It should be noted that the first network device 700 shown in FIG. 7 may be the network device 130 in the example shown in FIG. 3, or the first network device mentioned in the method 100 shown in FIG. 4. Therefore, For various specific embodiments of the first network device 700, reference may be made to the corresponding embodiment of FIG. 3 and the related introduction of the method 100, which will not be repeated in this embodiment.

Correspondingly, an embodiment of the present application also provides a second network device 800, as shown in FIG. 8. The second network device 800 is applied to a CR-LSP scenario of a label-switched path with restricted paths. The second network device 800 includes a sending unit 801, a receiving unit 802, and a processing unit 803.

The sending unit 801 is configured to send a first packet to the first network device via the first LSP to be detected, the first packet carrying path information of the first LSP, and the source node of the first LSP is the second network Device, the destination node is a first network device, and the first LSP includes a plurality of label switching node LSRs arranged in sequence.

The receiving unit 802 is configured to receive a first bidirectional link detection BFD message sent by the first network device via a second LSP, where the second LSP is established by the second network device based on path information, and the second LSP includes multiple LSRs , And the arrangement order of the multiple LSRs in the second LSP is opposite to the arrangement order of the multiple LSRs in the first LSP.

The processing unit 803 is configured to determine the detection result of the first LSP based on the first BFD packet.

In some implementation manners, the sending unit 803 in the second network device 800 is further configured to send the second BFD packet to the first network device via the first LSP.

In other implementation manners, the receiving unit 802 in the second network device 800 is further configured to receive a second packet sent by the first network device. The second packet carries capability information, and the capability information is used to characterize the first network device. Have the ability to establish a second LSP.

In still other implementation manners, the processing unit 803 in the second network device 800 is further configured to, before receiving the first bidirectional link detection BFD message sent by the first network device via the second LSP, based on the first LSP and the first LSP The second LSP negotiates BFD configuration parameters with the first network device; then, the receiving unit 802 is specifically configured to receive the first BFD message sent by the first network device via the second LSP based on the negotiated configuration parameters.

In still other implementation manners, the processing unit 803 in the second network device 800 is further configured to switch the traffic carried on the first LSP to the third LSP if the detection result indicates that the first LSP is faulty. The source node is the second network device, and the destination node of the third LSP is the first network device.

It should be noted that the second network device 800 shown in FIG. 8 may be the network device 110 in the example shown in FIG. 3, or the second network device mentioned in the method 100 shown in FIG. 4. Therefore, For various specific embodiments of the second network device 800, reference may be made to the corresponding embodiment of FIG. 3 and the related introduction of the method 100, which will not be repeated in this embodiment.

Referring to FIG. 9, an embodiment of the present application provides a first network device 900. The first network device 900 may be the destination node in any of the foregoing embodiments, for example, it may be the network device 130 in the embodiment shown in FIG. 3, or may be the first network device in the embodiment shown in FIG. The first network device 900 includes at least one processor 901, a bus system 902, a memory 903, and at least one transceiver 904.

The first network device 900 is a device with a hardware structure, and can be used to implement the functional modules in the first network device 700 shown in FIG. 7. For example, those skilled in the art can imagine that the processing unit 703 in the first network device 700 shown in FIG. 7 can be implemented by calling the code in the memory 903 by the at least one processor 901. The first network device 700 shown in FIG. 7 The receiving unit 701 and the sending unit 702 in can be implemented by the transceiver 904.

Optionally, the first network device 900 may also be used to implement the function of the first network device in any of the foregoing embodiments.

Optionally, the aforementioned processor 901 may be a general-purpose central processing unit (central processing unit, CPU), network processor (NP), microprocessor, application-specific integrated circuit (ASIC) , Or one or more integrated circuits used to control the execution of the program of this application.

The above-mentioned bus system 902 may include a path for transferring information between the above-mentioned components.

The aforementioned transceiver 904 is used to communicate with other devices or a communication network.

The aforementioned memory 903 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, a random access memory (RAM), or other types that can store information and instructions. The type of dynamic storage device can also be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), or other optical disk storage, optical discs Storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or can be used to carry or store desired program codes in the form of instructions or data structures and can be used by Any other medium accessed by the computer, but not limited to this. The memory can exist independently and is connected to the processor through a bus. The memory can also be integrated with the processor.

Among them, the memory 903 is used to store application program codes for executing the solutions of the present application, and the processor 901 controls the execution. The processor 901 is configured to execute the application program code stored in the memory 903, so as to realize the functions in the method of the present patent.

In a specific implementation, as an embodiment, the processor 901 may include one or more CPUs, such as CPU0 and CPU1 in FIG. 9.

In a specific implementation, as an embodiment, the first network device 900 may include multiple processors, such as the processor 901 and the processor 907 in FIG. 9. Each of these processors can be a single-CPU (single-CPU) processor or a multi-core (multi-CPU) processor. The processor here may refer to one or more devices, circuits, and/or processing cores for processing data (for example, computer program instructions).

Referring to FIG. 10, an embodiment of the present application provides a second network device 1000. The second network device 1000 may be the source node in any of the foregoing embodiments, for example, it may be the network device 110 in the embodiment shown in FIG. 3, or may be the second network device in the embodiment shown in FIG. 4 . The second network device 1000 includes at least one processor 1001, a bus system 1002, a memory 1003, and at least one transceiver 1004.

The second network device 1000 is a device with a hardware structure, and can be used to implement the functional modules in the second network device 800 described in FIG. 8. For example, those skilled in the art can imagine that the processing unit 803 in the second network device 800 shown in FIG. 8 can be implemented by calling the code in the memory 1003 by the at least one processor 1001. The second network device 800 shown in FIG. 8 The receiving unit 802 and the sending unit 801 in can be implemented by the transceiver 1004.

Optionally, the second network device 1000 may also be used to implement the function of the second network device in any of the foregoing embodiments.

Optionally, the aforementioned processor 1001 may be a general-purpose central processing unit (central processing unit, CPU), network processor (network processor, NP), microprocessor, application-specific integrated circuit (ASIC) , Or one or more integrated circuits used to control the execution of the program of this application.

The above-mentioned bus system 1002 may include a path for transferring information between the above-mentioned components.

The above transceiver 1004 is used to communicate with other devices or communication networks.

The above-mentioned memory 1003 may be a read-only memory (ROM) or other types of static storage devices that can store static information and instructions, random access memory (RAM), or other types that can store information and instructions. The type of dynamic storage device can also be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), or other optical disk storage, optical discs Storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or can be used to carry or store desired program codes in the form of instructions or data structures and can be used by Any other medium accessed by the computer, but not limited to this. The memory can exist independently and is connected to the processor through a bus. The memory can also be integrated with the processor.

The memory 1003 is used to store application program codes for executing the solutions of the present application, and the processor 1001 controls the execution. The processor 1001 is configured to execute application program codes stored in the memory 1003, so as to realize the functions in the method of the present patent.

In a specific implementation, as an embodiment, the processor 1001 may include one or more CPUs, such as CPU0 and CPU1 in FIG. 10.

In a specific implementation, as an embodiment, the apparatus 1000 may include multiple processors, such as the processor 1001 and the processor 1007 in FIG. 10. Each of these processors can be a single-CPU (single-CPU) processor or a multi-core (multi-CPU) processor. The processor here may refer to one or more devices, circuits, and/or processing cores for processing data (for example, computer program instructions).

Referring to FIG. 11, an embodiment of the present application provides a network system 1100. The network system 1100 includes a first network device 1101 and a second network device 1102. The first network device 1101 may specifically be the first network device 700 shown in FIG. 7 or the first network device 900 shown in FIG. 9; the second network device 1102 may specifically be the second network device 800 shown in FIG. Or the second network device 1000 shown in FIG. 10.

Optionally, the first network device 1101 may be the first network device in the embodiment shown in FIG. 4 or the network device 130 in the embodiment shown in FIG. 3, and the second network device 1102 may be the implementation shown in FIG. 4. The second network device in the example or the network device 110 in the embodiment shown in FIG. 3.

In addition, the embodiment of the present application also provides a computer-readable storage medium. The computer-readable storage medium stores program codes or instructions. When it runs on a computer, the computer executes the implementation shown in Figure 3 or Figure 4 above. The method in any implementation mode in the example.

In addition, the embodiments of the present application also provide a computer program product, which when running on a computer, causes the computer to execute any one of the aforementioned methods 100.

It should be noted that, in this application, the process of using the BFD mechanism for fault detection and related definitions can be found in the “Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)” dated June 2010. Found in RFC5884, the entire content is incorporated here by reference, just like all statements, so I won’t repeat it here.

The "first" in the names of "first message" and "first LSP" mentioned in the embodiments of the present application is only used for name identification, and does not represent the first in order. This rule also applies to "second" and so on.

From the description of the foregoing implementation manners, it can be understood that those skilled in the art can clearly understand that all or part of the steps in the foregoing embodiment methods can be implemented by means of software and a general hardware platform. Based on this understanding, the technical solution of the present application can be embodied in the form of a software product, and the computer software product can be stored in a storage medium, such as read-only memory (English: read-only memory, ROM)/RAM, magnetic disk, An optical disc, etc., includes a number of instructions to enable a computer device (which may be a personal computer, a server, or a network communication device such as a router) to execute the methods described in the various embodiments or some parts of the embodiments of the present application.

The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the difference from other embodiments. In particular, as for the system embodiment and the device embodiment, since they are basically similar to the method embodiment, the description is relatively simple, and for related parts, please refer to the part of the description of the method embodiment. The above-described device and system embodiments are only illustrative. The modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules, that is, they may be located in One place, or it can be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the objectives of the solutions of the embodiments. Those of ordinary skill in the art can understand and implement without creative work.

The above descriptions are only the preferred embodiments of the present application, and are not used to limit the protection scope of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from this application, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the scope of protection of this application.

Claims

A fault detection method, characterized in that it is applied to a first network device in a CR-LSP scenario of a label-switched path of a restricted path, and the method includes:

Receive a first packet sent by a second network device via a first LSP to be detected, where the first packet carries path information of the first LSP, and the source node of the first LSP is the first network Device, the destination node of the first LSP is the second network device, and the first LSP includes a plurality of label switching node LSRs arranged in sequence;

According to the path information, a second LSP from the first network device to the second network device is established, the second LSP includes the multiple LSRs, and the multiple LSRs are in the second LSP The arrangement order in is opposite to the arrangement order of the multiple LSRs in the first LSP;

Send a first bidirectional link detection BFD packet to the second network device through the second LSP, so that the second network device determines the failure condition of the first LSP based on the first BFD packet.
The method according to claim 1, wherein the method further comprises:

Receiving a second BFD packet sent by the second network device through the first LSP.
The method according to claim 1 or 2, wherein the method further comprises:

Sending a second message to the second network device, the second message carrying capability information, and the capability information is used to characterize that the first network device has the ability to establish the second LSP.
The method according to any one of claims 1-3, wherein before sending a first bidirectional link detection BFD message to the second network device via the second LSP, the method further comprises:

Negotiate BFD configuration parameters with the second network device based on the first LSP and the second LSP;

The sending a first bidirectional link detection BFD message to the second network device through the second LSP is specifically:

Based on the configuration parameters determined through negotiation, the first BFD packet is sent to the second network device through the second LSP.
The method according to any one of claims 1 to 4, wherein the first message is an LSP-Ping message, and the path information uses the type length value TLV extended in the LSP-Ping message Field carry.
A fault detection method, characterized in that it is applied to a second network device in a CR-LSP scenario of a label-switched path of a restricted path, and the method includes:

Send a first packet to the first network device through the first LSP to be detected, the first packet carrying path information of the first LSP, and the source node of the first LSP is the second network device , The destination node is the first network device, and the first LSP includes a plurality of label switching node LSRs arranged in sequence;

Receive a first bidirectional link detection BFD message sent by the first network device via a second LSP, where the second LSP is established by the second network device based on the path information, and the second LSP includes all The multiple LSRs, and the sequence of the multiple LSRs in the second LSP is opposite to the sequence of the multiple LSRs in the first LSP;

Determine the detection result of the first LSP based on the first BFD packet.
The method according to claim 6, wherein the method further comprises:

Sending a second BFD packet to the first network device through the first LSP.
The method according to claim 6 or 7, wherein the method further comprises:

Receiving a second message sent by the first network device, the second message carrying capability information, and the capability information is used to characterize that the first network device is capable of establishing the second LSP.
The method according to any one of claims 6-8, wherein before the receiving the first bidirectional link detection BFD message sent by the first network device via the second LSP, the method further comprises :

Negotiate BFD configuration parameters with the first network device based on the first LSP and the second LSP;

The receiving the first bidirectional link detection BFD message sent by the first network device via the second LSP is specifically:

Receiving the first BFD packet sent by the first network device via the second LSP based on the configuration parameter determined through negotiation.
The method according to any one of claims 6-9, wherein the method further comprises:

If the detection result indicates that the first LSP is faulty, the traffic carried on the first LSP is switched to a third LSP, and the source node of the third LSP is the second network device, and the first LSP is The destination node of the third LSP is the first network device.
A network device, characterized in that it is applied to a label-switched path CR-LSP scenario of a restricted path, the network device is the first network device in the CR-LSP scenario, and the CR-LSP scenario further includes a second Network equipment, the first network equipment includes:

The receiving unit is configured to receive a first packet sent by the second network device via the first LSP to be detected, where the first packet carries path information of the first LSP, and the source of the first LSP The node is the first network device, the destination node of the first LSP is the second network device, and the first LSP includes a plurality of label switching node LSRs arranged in sequence;

A processing unit, configured to establish a second LSP from the first network device to the second network device according to the path information, the second LSP includes the multiple LSRs, and the multiple LSRs are in The arrangement order in the second LSP is opposite to the arrangement order of the multiple LSRs in the first LSP;

A sending unit, configured to send a first bidirectional link detection BFD packet to the second network device via the second LSP, so that the second network device determines the first LSP based on the first BFD packet The failure situation.
The network device according to claim 11, wherein:

The receiving unit is further configured to receive a second BFD packet sent by the second network device via the first LSP.
The network device according to claim 11 or 12, wherein:

The sending unit is further configured to send a second message to the second network device, the second message carrying capability information, and the capability information is used to characterize that the first network device is capable of establishing the second network device. LSP capabilities.
The network device according to any one of claims 11-13, wherein:

The processing unit is further configured to, before sending a first bidirectional link detection BFD message to the second network device via the second LSP, based on the first LSP and the second LSP, and the The second network device negotiates BFD configuration parameters;

Then, the sending unit is specifically used for:

Based on the configuration parameters determined through negotiation, the first BFD packet is sent to the second network device through the second LSP.
A network device, characterized in that it is applied to a label-switched path CR-LSP scenario of a restricted path, the network device is the second network device in the CR-LSP scenario, and the CR-LSP scenario further includes a first Network equipment, the second network equipment includes:

The sending unit is configured to send a first packet to the first network device via the first LSP to be detected, the first packet carrying path information of the first LSP, and the source node of the first LSP Is the second network device, the destination node is the first network device, and the first LSP includes a plurality of label switching node LSRs arranged in sequence;

The receiving unit is configured to receive a first bidirectional link detection BFD message sent by the first network device via a second LSP, the second LSP being established by the second network device based on the path information, the The second LSP includes the multiple LSRs, and the sequence of the multiple LSRs in the second LSP is opposite to the sequence of the multiple LSRs in the first LSP;

The processing unit is configured to determine the detection result of the first LSP based on the first BFD packet.
The network device according to claim 15, wherein:

The processing unit is further configured to switch the traffic carried on the first LSP to a third LSP if the detection result indicates that the first LSP is faulty, and the source node of the third LSP is the For the second network device, the destination node of the third LSP is the first network device.
A network system, characterized in that, the network system comprises the network device according to any one of claims 11-14 and the network device according to claim 15 or 16.
A computer-readable storage medium, wherein the computer-readable storage medium stores program codes or instructions, which when run on a computer, causes the computer to execute any one of the above claims 1-5 The method or the method of any one of claims 6-10.