WO2012058930A1

WO2012058930A1 - Method and system for link failure detection

Info

Publication number: WO2012058930A1
Application number: PCT/CN2011/075861
Authority: WO
Inventors: 孙明辉
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-11-02
Filing date: 2011-06-20
Publication date: 2012-05-10
Also published as: CN102457409B; CN102457409A

Abstract

The present invention provides a method and system for link failure detection. The method is applied to the directly-connected scenes of multi-equivalent links. The method includes the following steps: the first device on one end of the links receives Bidirectional Forwarding Detection (BFD) messages sent from the second device on the other end of the links, wherein the first device and the second device are both pre-configured with at least one BFD session bound with their own ports; when judging that the port bound with the BFD session does not receive a BFD message sent from the second device in a detection time, the first device confirms the failure of the link connected with the port occurs. With the present invention, the problem that the link failure is difficult to be discovered in time, which influences the transmission performance of the link, can be resolved.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a link fault detection method and system. BACKGROUND OF THE INVENTION With the development of communication networks, network devices are increasingly required to have the ability to quickly discover network failures between their neighbors. BFD (Bidirectional Forwarding Detection Protocol) is an international standard protocol. It is independent of the transmission medium and can detect the transmission fault of the transmission layer at both ends of the direct link. The bidirectional forwarding detection is performed by transmitting the BFD protocol message on the UDP port of the UDP (User Datagram Protocol) port number, and the neighboring device detects the BFD packet sent by the peer to implement the link and Detection of device forwarding function.

The format of the BFD protocol is as shown in Figure 1. It includes the version, data, test, length, source distinguisher, destination distinguisher, minimum TX interval, minimum RX interval, and minimum reflection RX interval of the BFD protocol. In the device, the BFD processing module assigns the relevant field of the BFD control packet, and then sends the processed BFD control packet to the protocol stack, encapsulates the transport layer, the network layer, and the link layer, and sends the packet to the directly connected device. Similarly, when receiving a BFD packet, it needs to be parsed by the protocol stack, and the BFD control of the application layer is parsed and then submitted to the BFD processing module. When the link between two devices (for example, device A and device B) is multiple equivalent links (such as an aggregation link), the BFD protocol is used to configure the session. The configuration information cannot be distinguished from the equivalent link. For each link, the BFD packet between device A and device B needs to select the physical link according to the load sharing mode used by the two devices. For example, as shown in Figure 2, device A and device B are directly connected through n links, and the n links are aggregated equivalent links. Only one BFD session can be configured between device A and device B. Then, the link selected by the BFD session is indeterminate, and may be any one of Ti to Tn, which is determined by a load sharing strategy used by the device used. In the related art, in the case of link aggregation, the transmission capability of the link is the number of links X and the transmission capability of a single link. If any of the equivalent links fails, because other equivalent links are still connected In this case, the link between the two devices is still connected, so the fault is difficult to be discovered in time. However, the transmission capacity of the entire link has been affected at this time, affecting the transmission performance of the link, and buried. The hidden danger of the entire equivalent link failure. In view of the problem that the link failure in the related art is difficult to be discovered in time, thereby affecting the transmission performance of the link, an effective solution has not been proposed yet. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a link fault detection method and system, which at least solves the problem that the link fault is difficult to be discovered in time, thereby affecting the transmission performance of the link. According to an aspect of the present invention, a link fault detection method is provided, which is applied to a multi-equivalent link direct connection scenario, including: a first device at one end of the link receives a second device sent at the other end of the link The two-way forwarding detection protocol BFD packet, the first device and the second device are pre-configured with at least one BFD session bound to the own port; and when the first device determines the port bound to the BFD session When the BFD packet sent by the second device is not received within the detection time, the link connected to the port is determined to be faulty. After the link fault is determined, the method further includes: discarding the received BFD packet. The method further includes: when the first device determines that the port bound to the BFD session receives the BFD packet sent by the second device within the detection time, determining that the link connected to the port does not fail. . The method further includes: when all the ports of the first device and the second device are bound to the BFD session, and each port of the second device has a BFD packet, if one or more of the first device The port does not receive the BFD packet sent by the second device within the detection time, and determines that the link connected to the port that does not receive the BFD packet sent by the second device is faulty. According to another aspect of the present invention, a link failure detecting apparatus is provided, which is applied to a multi-equivalent link direct connection scenario, including a first device at one end of the link and a second device at the other end of the link: The first device is configured to receive the bidirectional forwarding detection protocol BFD packet sent by the second device, where the first device and the second device are pre-configured with at least one BFD session bound to the own port; The port bound to the BFD session does not receive the BFD sent by the second device within the detection time. The packet is faulty, and the second device is configured to send the BFD packet to the first device. The first device is configured to: after determining that the link connected to the port bound to the BFD session is faulty, discard the received BFD message. The first device is configured to: when it is determined that the port bound to the BFD session receives the BFD packet sent by the second device within the detection time, it is determined that the link connected to the port does not fail. When all the ports of the first device and the second device are bound to the BFD session, the second device is configured to: send a BFD packet on each port; the first device is configured to: If each port sends a BFD packet, if one or more ports of the port do not receive the BFD packet sent by the second device within the detection time, the device does not receive the second device. The link connected to the port of the BFD packet is faulty. The link fault detection method provided by the embodiment of the present invention can quickly determine a link with a link fault in a scenario where multiple equivalent links are directly connected, and can subsequently process the link with the link fault in time to avoid The link communication capability is degraded. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a BFD protocol message format according to the related art; FIG. 2 is a schematic diagram of device A and device B directly connected through n links according to an embodiment of the present invention; FIG. 4 is a schematic diagram of a direct connection between a device and a receiving device through n links according to an embodiment of the present invention; FIG. 5 is a link failure according to an embodiment of the present invention; FIG. 6 is a schematic diagram of a second structure of a link fault detection system according to an embodiment of the present invention; FIG. FIG. 2 is a flowchart of a link failure detecting method implemented by a second link failure detecting system according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. In the related art, if any one of the equivalent links fails, because the other equivalent links are still connected, the link between the two devices is still connected, so that the fault is difficult to be discovered in time, thereby Affecting the transmission performance of the link, the hidden danger of the entire equivalent link failure is buried. To solve the above technical problem, the embodiment of the present invention provides a link fault detection method, which is applied to a multi-equivalent link direct connection scenario. The processing flow is as shown in FIG. 3, and includes: Step 302: A device receives a bidirectional forwarding detection protocol BFD packet sent by the second device at the other end of the link, and the first device and the second device are pre-configured with at least one BFD session bound to the own port; Step 304: When the first device If the port bound to the BFD session does not receive the BFD packet sent by the second device within the detection time, the link connected to the port is determined to be faulty. The link fault detection method provided by the embodiment of the present invention can quickly determine a link with a link fault in a scenario where multiple equivalent links are directly connected, and can subsequently process the link with the link fault in time to avoid The link communication capability is degraded. In the implementation, when the link that is connected to the port that is bound to the BFD session is faulty, the following is also included: Discarding the received BFD 4 message. In the implementation, when the first device determines that the port bound to the BFD session receives the BFD packet sent by the second device within the detection time, it determines that the link connected to the port is not faulty. Since there are multiple equivalent direct links between the first device and the second device, multiple equivalent direct links can be detected by using an equivalent link full port configuration, that is, in the second Each port of the device is bound to a BFD session. In this case, if one or more ports of the first device do not receive BFD packets within the detection time, the link connected to the port that has not received the BFD packet is faulty. . In the above embodiment, the first device and the second device are only configured to distinguish different devices at both ends of the link. In a specific implementation, the first device may receive the BFD message sent by the second device, or send the BFD packet to the device. The second device, that is, the sender and the receiver can be mutually. Detailed descriptions are made from the perspective of the receiver and the sender respectively. For details, please refer to the following. In order to describe the process more clearly, the names of the first device and the second device are not used here, but directly called the transmitting device and the receiving device. Of course, in the following text, both the sending device and the receiving device are corresponding, and the roles can be exchanged.

1) Before the detection, you can configure a BFD session to detect the equivalent link on the sending device and the receiving device, and specify the port number when configuring the BFD session. Specifically, for example, as shown in FIG. 4, the BFD session configured on the device is sent, and the source/destination address is the equivalent link address S of the sending device, the equivalent link address R of the receiving device, and the port number to be detected is specified. P(1<=P<=N, N is the total number of ports); correspondingly, the BFD session configured on the receiving device, the source/destination address is the equivalent link address R of the receiving device/the equivalent link address S of the transmitting device, And specify the port number P to be detected, (1<=P, <=N), where ports P and P are the two ports of the same physical connection.

2) After the configuration is complete, the sending device sends the encapsulated BFD packet from the designated port P. After receiving the packet, the receiving device records the port D that receives the packet. If the port receives the BFD control packet. If the number D' does not match the specified port number P', the 4 files are discarded. The sending device sends the encapsulated BFD packet from the designated port P, and the method includes: the sending device determines the BFD protocol packet information according to the configuration information, and the information format is as shown in FIG. 1 , and the BFD protocol packet is completed by using the encapsulating module. The encapsulation of the text is finally sent out through the detection port P specified in the configuration. The receiving device receives the BFD packet and records the receiving port number. If the port number of the BFD packet does not match the specified port number, the packet is discarded. The following includes: After receiving the packet received by the device, record the port D that receives the packet, and receive the received packet. If the packet is decapsulated and determined to be BFD 4, the BFD session is queried. If no BFD session is specified, the BFD session is discarded. As mentioned above, both the transmitting device and the receiving device are corresponding and can exchange roles. Therefore, the receiving device also initiates the same process to the transmitting device. If both the sending device and the receiving device are in each check During the measurement period, the BFD control with the port number matching the configuration is received, and the session is established and maintained. If one of the ports does not receive a valid BFD message within the detection time, the link corresponding to the designated port is considered to be faulty. Based on the same inventive concept, the embodiment of the present invention provides a link fault detection system. The structure is shown in FIG. 5, and is applied to a multi-equivalent link direct connection scenario, including a first device 501 and a chain at one end of the link. The second device 502 is located at the other end of the path. The first device 501 is configured to receive the bidirectional forwarding detection protocol BFD packet sent by the second device 502. The first device 501 and the second device 502 are pre-configured with at least one port tied to the port. Determining a BFD session; determining that the port bound to the BFD session does not receive the BFD message sent by the second device 502 within the detection time, determining that the link connected to the port is faulty; the second device 502, The BFD packet is sent to the first device 501. In an embodiment, the first device 501 may be configured to: after determining that the link connected to the port bound to the BFD session is faulty, discard the received BFD packet. In an embodiment, the first device 501 may be configured to: when it is determined that the port bound to the BFD session receives the BFD message sent by the second device 502 within the detection time, determine the chain connected to the port. The road has not failed. In an embodiment, when all the ports of the first device 501 and the second device 502 are bound to the BFD session, the second device 502 may be configured to: send a BFD message on each port; the first device 501 may When the BFD packet is sent to each port of the second device 502, if one or more ports of the second device 502 do not receive the BFD packet sent by the second device 502 within the detection time, the device determines that the BFD packet is not received. The link connected to the port of the BFD packet sent by the device 502 is faulty. The device A and the device B are still used as an example. In the specific implementation, the link fault detection system may be as shown in FIG. 6 , and includes the device A and the device B. The device A may include a BFD processing module and a package decapsulation module. And the physical layer transceiver module, and correspondingly, the device B also includes a BFD processing module, a package decapsulation module, and a physical layer transceiver module, and the BFD 4 files are transmitted between the two. When any one of device A or device B is used as a transmitting device, the implementation process of the device includes: BFD processing module: Implements the BFD protocol, configures the parameters of the BFD protocol packet, encapsulates the BFD packet, and determines the sending port specified by the session, and brings the port information specified in the configuration to the encapsulation module. Encapsulation module: BFD provided by the BFD processing module The protocol packet is encapsulated, including the transport layer, the network layer, and the link layer. The port provided by the BFD processing module is designated as the sending port. The sending module: sends the BFD 4 packet through the designated port. When any one of the device A or the device B is used as the sending device, the device includes: receiving the module: receiving the BFD packet, and recording the receiving port number; and parsing the module: decapsulating the packet, and according to UDP The port number is determined to be a BFD packet; the BFD protocol packet and the receiving port number are sent to the BFD processing module.

BFD processing module: The source IP address of the BFD session is searched in the BFD session configuration to determine whether the specified port number is the port that receives the packet in the session where the source destination address is configured. If not, Discard the 4 texts. When the link fault detection method is implemented by using the device shown in FIG. 6 , referring to FIG. 7 , the sending end may include the following steps: Step 702: Configure a BFD session for detecting a valid link, and specify a detection port number. Step 704: The BFD processing module sends the BFD session to the encapsulating module when the BFD session is generated. The encapsulating module encapsulates the BFD protocol packet and sends the port specified by the BFD session to the sending port. Step 706: The sending module sends the encapsulated BFD message to the designated port. Correspondingly, as shown in FIG. 7, the receiving end may include the following steps: Step 708: Configure a BFD session for detecting a valid link, and specify a detection port number; Step 710: The receiving module receives the BFD packet, and records The receiving port sends the BFD packet and the port number to the parsing module. The parsing module decapsulates the packet until it resolves to the UDP layer, and determines the BFD packet according to the UDP port number. Step 712: The BFD packet and the receiving port number are transmitted to the BFD processing module. After receiving the BFD packet, the BFD processing module finds whether the specified port number included in the BFD packet configuration includes the BFD packet receiving port number. If the specified port matches the receiving port number of the BFD packet, the packet is discarded; otherwise, a valid BFD session packet is received. From the above description, it can be seen that the present invention achieves the following technical effects: The link fault detection method provided by the embodiment of the present invention can quickly determine the link fault in a scenario where multiple equivalent links are directly connected. The link can be processed in time for the link with link failure to avoid the link communication capability. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A link fault detection method is applied to a multi-equivalent link direct connection scenario, including:

The first device at one end of the link receives the bidirectional forwarding detection protocol BFD packet sent by the second device at the other end of the link, and the first device and the second device are pre-configured with at least one BFD bound to the own port. Conversation;

When the first device determines that the port bound to the BFD session does not receive the BFD packet sent by the second device within the detection time, it determines that the link connected to the port is faulty.

The method according to claim 1, wherein, after the determining that the link connected to the port is faulty, the method further includes: discarding the received BFD packet.

3. The method according to claim 1, further comprising:

When the first device determines that the port bound to the BFD session receives the BFD packet sent by the second device within the detection time, it determines that the link connected to the port does not fail.

The method according to any one of claims 1 to 3, further comprising:

All the ports of the first device and the second device are bound to the BFD session, and each port of the second device has a BFD 4 message, if one or more ports of the first device are detected. The link failure of the BFD packet sent by the second device is not received, and the link connected to the port that does not receive the BFD packet sent by the second device is determined to be faulty.

5. A link fault detection system, which is applied to a multi-equivalent link direct connection scenario, including a first device at one end of the link and a second device at the other end of the link:

The first device is configured to receive a bidirectional forwarding detection protocol BFD packet sent by the second device, where the first device and the second device are pre-configured with at least one BFD session bound to the own port; If the port bound to the BFD session does not receive the BFD packet sent by the second device within the detection time, the link connected to the port is determined to be faulty; the second device is set to the first A device sends the BFD packet. The system according to claim 5, wherein the first device is configured to: after determining that the link connected to the port bound to the BFD session is faulty, discard the received BFD packet. The system according to claim 5, wherein the first device is configured to: when it is determined that the port bound to the BFD session receives the BFD packet sent by the second device within the detection time, The link connected to this port has not failed. The system according to any one of claims 5 to 7, wherein when all the ports of the first device and the second device are bound to the BFD session, the second device is configured to: issue BFD 4 on each port. Obituary

The first device is configured to: when each port of the second device sends a BFD packet, if one or more ports of the second device do not receive the BFD packet sent by the second device within the detection time, And determining a link failure connected to the port that does not receive the BFD 4 message sent by the second device.