WO2021018150A1

WO2021018150A1 - Link detection method and apparatus

Info

Publication number: WO2021018150A1
Application number: PCT/CN2020/105265
Authority: WO
Inventors: 张梅刚; 杨冰
Original assignee: 华为技术有限公司
Priority date: 2019-07-29
Filing date: 2020-07-28
Publication date: 2021-02-04
Also published as: CN112311613A

Abstract

A link detection method, comprising: negotiating and establishing a time-out period of a BFD session during the process of upper applications of two network devices establishing a session, and configuring and initiating a timer according to the negotiated time-out period; and during the establishment of the BFD session, if the establishment of the BFD session is not completed by the time the timer expires, interrupting the established application layer session. In this way, if a BFD session is not established for a long time, an application layer session is interrupted, a path between two network devices is converged, and data is not sent to the path, thereby reducing data loss.

Description

Method and device for link detection

This application claims the priority of the Chinese application filed on July 29, 2019, the application number is 201910691227.8, and the invention title is "a method and device for link detection", the entire content of which is incorporated into this application by reference.

Technical field

The present invention relates to the field of network technology, in particular to a method and device for link detection in a network.

Background technique

Border Gateway Protocol (Border Gateway Protocol, BGP) is a dynamic routing protocol used between Autonomous Systems (AS). It achieves reachability between ASs by maintaining IP routing tables or ‘prefix’ tables. When two ASs need to exchange routing information, each AS must designate a node running BGP to exchange routing information with other ASs on behalf of the AS. This node can be a host, but it is usually a router to perform BGP. The routers in the two ASs that use BGP to exchange information are also called Border Gateways or Border Routers. BGP nodes that exchange messages are called peers.

BGP uses Transmission Control Protocol (TCP) as its transport layer protocol. A TCP connection is established between BGP peers first, and after the TCP connection is established, a connection relationship (ie, a BGP session) between the BGP peers is established through an Open message (start message). After that, the BGP node will periodically send Keepalive messages (keep messages) to the peer to maintain the validity of the connection. In other words, BGP can implement the neighbor detection mechanism by periodically sending Keepalive messages. However, under normal circumstances, the sending cycle of Keepalive messages is more than 1 second. Therefore, the detection cycle of this detection mechanism is relatively long. When the data reaches the Gbit/s rate level, the detection time of this mechanism will cause a large amount of data loss .

At present, in order to speed up BGP convergence, the BGP protocol introduces the bidirectional forwarding detection (BFD) and BGP linkage function, and uses the fast detection mechanism of BFD to quickly discover the link failures between BGP peers and report them to the BGP protocol. , So as to achieve rapid convergence of BGP routing. Among them, BFD is a universal and standardized rapid fault detection mechanism that is independent of media and protocol. BFD establishes a session on two network devices to detect the bidirectional forwarding path between the network devices and serve upper-layer applications. BFD itself does not have a neighbor discovery mechanism, but relies on the served upper application to notify its neighbor information to establish a session. After the session is established, BFD packets will be quickly sent periodically. If no BFD packets are received within the detection time, it is considered that the bidirectional forwarding path has failed, and the served upper layer application is notified to perform corresponding processing. When implementing BFD and BGP linkage, after a BGP node establishes a BGP session with a peer, the BGP node establishes a BFD session with the peer based on the peer information, and uses BFD to detect link failures. When a link failure is detected, the BFD session between the BGP node and the peer is interrupted, and the BGP session between the associated BGP node and the peer is interrupted. Because BFD can achieve millisecond level detection, BGP can achieve rapid convergence through linkage.

However, the problem with using the BFD detection mechanism in BGP is that the establishment of the BFD session and the establishment of the BGP session are asynchronous, that is, the establishment of the BFD session starts after the establishment of the BGP session. If link flutter occurs after the BGP session is established and before the BFD session is established, BGP can only rely on Keeplive to detect the status of the peer, which may still cause data loss for a long period of time.

Summary of the invention

The present invention provides a method and a device for dividing an IGP domain in a network to solve the problem of high maintenance overhead during network expansion or adjustment in the prior art.

To achieve the above objective, the present invention adopts the following technical solutions:

In the first aspect, an embodiment of the present invention provides a link detection method, which is applied in a linkage scenario where the upper layer is applied to BFD. The method includes: the first network device and the second network device negotiate a timeout period for establishing a bidirectional forwarding detection (BFD) session in the process of establishing an application layer session. The first network device sets and starts a timer according to the negotiated timeout time, and establishes a bidirectional forwarding detection (BFD) session with the second network device. If the establishment of the BFD session is not completed before the timer ends, the first network device interrupts the application layer session with the second network device. By implementing the solution of the embodiment of the present invention, if the BFD session is not established for a long time, the application layer session will be interrupted, the path between the two network devices will be converged, and data will not be sent to the path, thereby reducing data loss.

If the establishment of the BFD session has been completed before the timer ends, the first network device performs link detection through the BFD session. In the case that the BFD session is successfully established, the embodiment of the present invention may use BFD to quickly detect the link, thereby accelerating the convergence speed.

In some possible implementation manners, the first network device and the second network device may carry the timeout period defined for the BFD session in the negotiation message for establishing the application layer session. Then, one of the timeout periods defined by the first network device and the second network device is selected as the timeout period of the BFD session. By using the negotiation message of the application layer session to negotiate the timeout period of the BFD session, the changes to the device can be reduced and the implementation of the solution is easier.

In some possible implementation manners, the solutions of the embodiments of the present invention can be applied to the linkage between BGP and BFD. In this case, the first network device and the second network device can be Border Gateway Protocol (BGP) nodes, and the first The network device and the second network device respectively carry the timeout time defined for the BFD session in the negotiation message for establishing the application layer session, including: after the first network device establishes a connection with the second network device , Sending a first start (OPEN) message to the second network device, and receiving a second OPEN message sent by the second network device, in the first OPEN message and the second OPEN message Respectively carry the timeout time defined by the first network device and the second network device for the BFD session. In the scenario of BGP and BFD linkage, the embodiment of the present invention directly uses the OPEN message to implement the negotiation of the timeout time, which not only improves the ease of implementation, but also achieves good compatibility.

In some possible implementations, the first OPEN message and the second OPEN message carry the timeout time defined for the BFD session through a BFD enable field (BFD enable TLV); the BFD The enable TLV includes the type, length, and value, and the timeout period defined for the BFD session is carried in the value of the BFD enable TLV.

In some possible implementation manners, the first network device and the second network device may select a maximum time value from the timeout time defined by the first network device and the second network device as the timeout time of the BFD session.

In the second aspect, the present invention provides a network device. The network device is used to execute the first aspect or the method in any possible implementation manner of the first aspect. Specifically, the network device includes a module for executing the method in the first aspect or any possible implementation of the first aspect, for example, a negotiation unit that performs functions related to negotiation in an application layer session, and performs a BFD session A BFD unit that establishes related functions, and an interrupt unit that performs interrupt processing for judging whether the establishment of a BFD session has timed out and after the timeout.

In a third aspect, the present invention provides a network device, which includes a communication interface, a processor, a memory, and a bus. Among them, the processor is respectively coupled to the communication interface and the memory through the bus. Among them, when the network device needs to be operated, the basic input output system solidified in the memory or the bootloader in the embedded system is used to guide the system to start, and the network device is guided to enter a normal operating state. After the network device enters the normal operating state, the application program and the operating system in the memory are then run, so that the processor executes the first aspect or the method in any possible implementation manner of the first aspect.

In a fourth aspect, the present invention provides a computer-readable medium for storing a computer program, and the computer program includes instructions for executing the first aspect or any possible implementation of the first aspect.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

FIG. 1 is a schematic diagram of a networking of an upper-layer application and BFD linkage provided by an embodiment of the present invention;

Figure 2 is an interaction diagram of a link detection method provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a BGP network provided by an embodiment of the present invention;

Figure 4 is a flowchart of a link detection method provided by an embodiment of the present invention;

FIG. 5 is a schematic diagram of a format of BFD enable TLV provided by an embodiment of the present invention;

Figure 6 is a schematic structural diagram of a network device provided by an embodiment of the present invention;

Fig. 7 is a schematic structural diagram of a network device provided by an embodiment of the present application.

Detailed ways

The technical solution in this embodiment will be clearly and completely described below in conjunction with the drawings in this embodiment.

Currently, in order to perform rapid detection, many upper-layer applications have introduced the linkage function with BFD. The linkage function means that upper-layer applications use BFD's rapid detection mechanism to quickly find link failures and report them to the upper-layer applications, so that the upper-layer applications quickly converge. However, in the process of linkage with BFD, the establishment of application layer sessions (that is, the sessions of upper-layer applications) and the establishment of BFD sessions are asynchronous, which leads to link failures during the establishment of the upper-layer application sessions but the BFD session is not established. It is impossible to use BFD to quickly find out, which may result in data loss for a long period of time.

To solve this problem, the embodiment of the present invention negotiates the timeout period for establishing the BFD session during the process of establishing the session by the upper application of the two network devices, and sets and starts the timer according to the negotiated timeout period. When the BFD session is established, If the establishment of the BFD session is not completed at the end of the timer, the established application layer session is interrupted. In this way, if the BFD session is not established for a long time, the application layer session will be interrupted, the path between the two network devices will be converged, and data will not be sent to the path, thereby reducing data loss.

The solution of the embodiment of the present invention can be applied in a scenario where an upper layer application and BFD are linked. As shown in FIG. 1, FIG. 1 is a schematic diagram of a networking of an upper layer application and BFD linkage provided by an embodiment of the present invention. The networking includes network devices 101-104. Among them, the network device can be a host, a router, or a switch. Network devices can be located in the same network or in different networks. The network device 101 establishes an application layer session with the network device 103 and the network device 104 respectively, and establishes a BFD session after the establishment of the application layer session is completed. Assume that the route outbound interface from the network device 101 to the network device 102 is the interface 1, and the network device 103 reaches the network device 102 through the network device 103. When the link between the network device 101 and the network device 103 fails, the BFD first perceives and informs the upper layer application of the network device 103. The network device 103 processes the Down event (that is, interrupts the application layer session), re-calculates the route, and the new route outgoing interface is interface 2, which passes through the network device 104 to the network device 102. The above is the linkage process between upper-layer applications and BFD. The embodiment of the present invention further supplements the above process. In the embodiment of the present invention, when the network device 101 and the network device 103 establish an application layer session, they further negotiate the timeout period for establishing a BFD session. During the process, if it times out, the network device 101 also performs Down event processing to converge the link between the network device 101 and the network device 103, and the new route outgoing interface is interface 2, which passes through the network device 104 to the network device 102. That is to say, in the embodiment of the present invention, the application layer session will be interrupted in the case of link failure and BFD session establishment timeout, so as to avoid long-term data loss.

When the above-mentioned solution is specifically implemented, it mainly involves the use of two network devices (for example, network device 101 and network device 103) that link upper-layer applications with BFD. In the embodiment of the present invention, these two network devices are referred to as a first network device and a second network device, and the first network device and the second network device may be referred to as opposite end network devices. Generally, when the first network device and the second network device establish an application layer session, they perform application layer session negotiation. In the embodiment of the present invention, the negotiation of the timeout period for establishing the BFD session can be added to the negotiation message of the application layer session. The specific implementation process is shown in Figure 2, which is an interaction diagram of the link detection method provided by an embodiment of the present invention. The method includes an application layer session establishment process and a BFD session establishment process.

Among them, the application layer session establishment process includes:

Steps S201-S202: The first network device sends a negotiation message for establishing an application layer session to the second network device, and receives a negotiation message for establishing an application layer session sent by the second network device. Wherein, the first network device and the second network device send the negotiation message to carry the timeout time defined for the BFD session.

The negotiation message may be a message with a negotiation function during the session establishment process, for example, a session creation message or an initial message.

The BFD session establishment process includes:

Steps S203-S204, the first network device and the second network device select one of the timeout periods defined by the first network device and the second network device as the timeout period of the BFD session, and the first network device and the second network device negotiate Set the timeout period and start the timer.

When selecting, the first network device and the second network device can be selected according to a uniform rule. For example, the maximum time value can be selected as the timeout time of the BFD session in the timeout time. The timeout time selected according to the uniform rule is the timeout time of the negotiated BFD session.

Step S205: The first network device and the second network device start to establish a BFD session.

Step S206: It is judged whether the establishment of the BFD session is completed before the timer ends.

If the establishment of the BFD session is not completed before the timer ends, the first network device interrupts the application layer session with the second network device. If the establishment of the BFD session is completed before the timer ends, the first network device detects the link with the second network device through the BFD session.

Through the above method, the occurrence of a situation where link detection cannot be performed for a long time is avoided, and data loss can be effectively reduced.

The solution of the embodiment of the present invention can be applied to scenarios where a variety of upper-layer applications and BFD are linked, for example, BFD is linked with Open Shortest Path First (OSPF), and BFD is linked with an intermediate system to an intermediate system (Intermediate System). to Intermediate System (IS-IS) linkage, BFD and BGP linkage, BFD and Virtual Router Redundancy Protocol (VRRP) linkage, etc. In different linkage scenarios, the upper layer application protocols enabled on the first network device and the second network device are different. For example, in the scenario of BFD and OSPF linkage, the first network device and the second network device may be devices with OSPF enabled. In the scenario of BFD and IS-IS linkage, the first network device and the second network device It may be a device with the IS-IS function enabled; in the scenario where BFD and BGP are linked, the first network device and the second network device may be devices with the BGP function enabled. For ease of understanding, the embodiment of the present invention takes the linkage of BFD and BGP as an example for description.

In order to facilitate the understanding of the various embodiments of the present application, firstly, several concepts that may appear in the scenario where BFD and BGP are linked are introduced. It should be understood that the following conceptual explanations may be limited due to the specific circumstances of this application, but it does not mean that this application can only be limited to this specific situation. The following conceptual explanations may also exist with specific circumstances of different embodiments. difference.

There are two roles in BGP message interaction: Speaker and Peer.

Speaker: The device that sends BGP messages is called the BGP speaker. It receives or generates new message information and advertises to other BGP Speakers. The BGP speaker is a BGP-enabled network device. For ease of description, in the embodiment of the present invention, BGP Speaker is referred to as a BGP node.

Peer: Speakers exchanging messages are called peers or neighbors.

BGP is generally applied between ASs, as shown in FIG. 3, which is a schematic structural diagram of a network using BGP according to an embodiment of the present invention. The network includes two autonomous systems, AS1 and AS2. AS1 includes

BGP nodes

101, 102, 103. AS2 includes

BGP nodes

104 and 105. A BGP node is a network device with the BGP function enabled. The network device can be a host, router, switch, etc. Among them, the BGP nodes at both ends shown by the dotted arrows are peers. For example, the BGP node 101 is a peer of the BGP node 102, and the BGP node 102 is also a peer of the BGP node 101. AS1 and AS2 exchange information through the BGP node 102 and the BGP node 104. It should be noted that not any two BGP nodes can interact with each other. Two BGP nodes must form a pair (ie BGP peer) to interact. Two BGP nodes establish a BGP session to form a peer. If the two BGP nodes that form a peer have the BFD capability enabled, the two BGP nodes can further establish a BFD session, and realize rapid detection through the linkage between BGP and BFD. When two BGP nodes realize the linkage between BGP and BFD, the solution of the embodiment shown in FIG. 2 can be implemented to reduce data loss.

The implementation of fast detection in BGP will be described in detail below in conjunction with Figure 4. Fig. 4 is a flowchart of a link detection method provided by an embodiment of the present invention. The method includes:

S401: The first BGP node establishes a TCP connection with the second BGP node.

BGP uses TCP as its transport layer protocol. Before establishing a BGP session, a TCP connection can be established first. The process of establishing the TCP connection can adopt the existing technology, which will not be repeated here.

S402: The first BGP node sends a BGP start message (ie, BGP OPEN message) for establishing a BGP session to the second BGP node, and the BGP OPEN message carries the timeout period for establishing a BFD session defined by the first BGP node.

The Open message (start message) is the first message sent after the TCP connection is established, and is used to establish a connection relationship between BGP peers (ie, a BGP session). This message can negotiate various capabilities when the BGP session is initially established, such as address family capabilities, Refresh capabilities, GR (Graceful Restart) capabilities, and so on. The embodiment of the present invention may use the message to negotiate the BFD capability, and the negotiated BFD capability may include the timeout period for establishing the BFD session.

Specifically, a BFD enable field (BFD enable TLV) can be added to the OPEN message to negotiate BFD capabilities. Type-Length-Value (Type-Length-Value, TLV) is a message format. The BFD enable TLV is used to inform the local BFD capability (that is, whether to support BFD) and negotiate the timeout period for establishing a BFD session. For BFD-enable TLV, refer to FIG. 5, which is a schematic diagram of a format of BFD-enable TLV according to an embodiment of the present invention. Among them, the meaning of each parameter in the message format is as follows:

Type: TLV type (identifies whether BFD is enabled)

Length: Length (2Byte)

Value: Timer (identifies the timer time, this parameter can be used to define the timeout time for establishing a BFD session)

The configurable range of Timer is 1-65534, and the maximum value of 65535 means that the timer is not enabled.

The BGP OPEN message sent by the first BGP node to the second BGP node may carry BFDenable TLV to indicate that the first BGP node has enabled the BFD capability. Among them, the Value in the BFDenable TLV can be set to 10, which means that the timer is set to 10S, that is, the timeout period for establishing a BFD session defined by the first BGP node is 10S.

S403: The second BGP node sends a BGP OPEN message to the first BGP node, and the BGP OPEN message carries the timeout period for establishing a BFD session defined by the second BGP node.

Similarly, the BGP OPEN message sent by the second BGP node to the first BGP node may also carry BFDenable TLV to indicate that the second BGP node has enabled the BFD capability. Among them, the Value in the BFDenable TLV can be set to 20, which means that the timer is set to 20S, that is, the timeout period for establishing a BFD session defined by the second BGP node is 20S.

S404-S405: After receiving the BGP OPEN message sent by the opposite end, the first BGP node and the second BGP node send a Keepalive message to the opposite end for confirmation, and keep the connection.

After receiving the Keepalive message from the peer, the BGP session is established.

S406-S408: After the BGP session is established, the first BGP node and the second BGP node respectively set and start timers according to the received BGP OPEN message, and establish a BFD session.

The first BGP node and the second BGP node negotiate a timer value (that is, the timeout period for establishing a BFD session) according to the BFDenable TLV carried in the BGP OPEN message. Specifically, the larger value (such as 20s) of the timer values defined by the two can be taken as the timer value, the timer is set, and the timer is started.

It should be noted that if the received BGP OPEN message does not carry BFD enable TLV, it means that the other party does not support BFD enable TLV or has no BFD capability. In this case, the timer is not started. In this embodiment, the carrying of BFD-enable TLV is taken as an example for description.

The establishment of the BFD session can be achieved by using the existing technology, which will not be repeated here.

S409: Before the timer expires, the establishment of the BFD session is not completed, and the first network device and the second network device send a BGP notification (Notification) message to each other to interrupt the BGP session with each other.

The BGP Notification message is a message to notify that an error has been detected. After the first network device and the second network device send the BGP Notification message, they will set the peer down at the local end (that is, the BGP session with the peer will be interrupted).

In this embodiment, the establishment of the BFD session is not completed before the timer expires as an example. If the establishment of the BFD session is completed before the timer ends, the first network device and the second network device pass the established Link detection for the BFD session.

The process of link detection by the BFD session can be implemented with reference to the prior art, which will not be repeated here.

The foregoing embodiment implements the control over whether the establishment of the BFD session is overtime by extending the OPEN message in the BGP, which greatly reduces the service damage time. Moreover, the method of expanding existing messages makes the changes to existing equipment small and has good compatibility.

The above description is based on the linkage between BFD and BGP as an example. In other scenarios where upper-layer applications are linked with BFD, you can refer to the similar implementation of BFD and BGP linkage, which will not be repeated here.

Fig. 6 schematically shows a network device 600 provided by an embodiment of the present invention. The network device 600 includes a negotiation unit 601, a BFD unit 602, and an interrupt unit 603.

Wherein, the negotiating unit 601 is configured to negotiate a timeout period for establishing a bidirectional forwarding detection (BFD) session with the peer network device in the process of establishing an application layer session. For example, when the network device to which the negotiation unit 601 belongs is the first network device or the first BGP node in the foregoing method embodiment, the peer network device is the second network device or the second BGP node in the foregoing method embodiment. For the specific implementation of the negotiation unit 601, refer to the function of the first network device or the first BGP node and the second network device or the second BGP node in the method embodiments shown in FIG. 2 and FIG. 4 to negotiate a timeout period for establishing a BFD session.

The BFD unit 602 is configured to set and start a timer according to the timeout time negotiated by the negotiation unit 601, and establish a bidirectional forwarding detection (BFD) session with the peer network device. For the specific implementation of the BFD unit 602, refer to the part of the first network device or the first BGP node in the method embodiments shown in FIG. 2 and FIG. 4 for setting a timer and establishing a BFD session.

The interrupting unit 603 is configured to interrupt the application layer session with the peer network device when the BFD unit 602 does not complete the establishment of the BFD session before the timer ends. For the specific implementation of the interrupt unit 603, refer to the part of the first network device or the first BGP node interrupting the application layer session with the second network device or the second BGP node in the method embodiments shown in FIG. 2 and FIG. 4.

The BFD unit 602 may also perform link detection through the established BFD session when the establishment of the BFD session has been completed before the timer ends.

The above-mentioned network equipment can be used in different scenarios to enable different upper-layer application functions. For example, in a scenario where BFD and BGP are linked, the network equipment can enable the BGP function and execute the first method in the method embodiment shown in Figure 4. The function of the BGP node or the second BGP node.

It should be understood that the network device 600 here is embodied in the form of a functional unit. In an optional example, those skilled in the art can understand that the network device 600 may correspond to the network device in the foregoing embodiment. The first network device, the second network device, the first BGP node, and the second BGP node can be used In order to avoid repetition, the various processes and/or steps corresponding to the related equipment in the foregoing method embodiments are not repeated here.

Generally, the network device (for example, the first network device, the second network device, the first BGP node, the second BGP node) implementing the embodiments of the present invention may be a host, a router, or a switch. The hardware structure of the network device in the embodiment of the present invention is introduced below. Figure 7 is a schematic structural diagram of a network device provided by an embodiment of the present invention. As shown in FIG. 7, the network device 700 includes: a communication interface 701, a processor 702, and a memory 703. Optionally, the network device 700 may further include a bus 704. Wherein, the communication interface 701, the processor 702, and the memory 703 may be connected to each other through a bus 704.

Among them, the processor may be composed of one or more general-purpose processors, such as a central processing unit (CPU). The processor can be used to run programs for processing functions in related program codes. That is to say, the program code executed by the processor can realize the functions of the negotiation unit, the BFD unit, and the interrupt unit in the embodiment shown in FIG. 6, or realize the function of the first network device in FIG. 2, and the first BGP in FIG. The function of the node.

The communication interface 701 may be a wired interface (such as an Ethernet interface) or a wireless interface (such as a cellular network interface or using a wireless local area network interface) for communicating with other modules or devices. For example, the communication interface 7011 in the first network device in the embodiment of the present application may be specifically used to receive a message sent by the second network device, or send a message to the second network device.

The memory 703 may include volatile memory (Volatile Memory), such as random access memory (Random Access Memory, RAM); the memory may also include non-volatile memory (Non-Volatile Memory), such as read-only memory (Read-Only Memory). Memory, ROM), Flash Memory (Flash Memory), Hard Disk Drive (HDD), or Solid-State Drive (SSD); the memory 703 may also include a combination of the foregoing types of memories. The memory may be used to store a set of program codes, so that the processor can call the program codes stored in the memory to implement the functions of the communication module and/or processing module involved in the embodiment of the present application, which is not limited in the embodiment of the present application.

The features, functions, and/or methods described in the embodiments of the present application (for example, the method shown in FIG. 2 or FIG. 4) may be implemented in the network device 700. For example, the features, functions, or methods in the embodiments of the present application may be implemented by hardware, firmware, and/or software installed and running on hardware. The network device 700 may be any device (for example, a switch, a router, a bridge, a server, a client, etc.) that transmits data through a network, a system, and/or a domain. In addition, network nodes, network components, network devices, network elements, and/or similar terms can be used interchangeably to describe network devices in general; and unless otherwise specified and/or stated in this application, these terms have no specific meaning. Or special meaning. In an example embodiment, the network device 700 may be a device for implementing the linkage between an upper layer application and BFD to detect a link. It should be noted that FIG. 7 is only a possible implementation of the embodiment of the present application. In practical applications, the network device may also include more or fewer components, which is not limited here. Regarding the content not shown or described in the embodiment of the present application, please refer to the relevant description in the embodiment described in FIG. 2 or FIG. 4, which will not be repeated here.

In other possible embodiments, the network device may also be a virtual network device implemented based on a general physical server and network function virtualization (English: Netwrk Function Virtulization, NFV) technology, and the virtual network device may be a virtual router. The virtual network device may be a virtual machine (Virtual Machine) running to provide an upper-layer application in conjunction with BFD to detect a link, and the virtual machine is deployed on a hardware device (for example, a physical server). Virtual machine refers to a complete computer system with complete hardware system functions that is simulated by software and runs in a completely isolated environment. This virtual network device performs all the functions and operations of the network device 600 or the network device 700.

An embodiment of the present invention also provides a computer non-transitory storage medium, which stores instructions in the computer non-transitory storage medium. When it runs on a processor, the flow of any method described in FIG. 2 or FIG. 4 Achieved.

The embodiment of the present invention also provides a computer program product. When the computer program product runs on a processor, any method flow described in FIG. 2 or FIG. 4 is realized.

The steps of the method or algorithm described in conjunction with the disclosure of the embodiments of the present invention may be implemented in a hardware manner, or may be implemented in a manner that a processor executes software instructions. Software instructions can be composed of corresponding software modules. The software modules can be stored in Random Access Memory (RAM), flash memory, Read Only Memory (ROM), and erasable programmable read-only memory (Random Access Memory, RAM). Erasable Programmable ROM (EPROM), Electrically Erasable Programmable Read-Only Memory (Electrically EPROM, EEPROM), register, hard disk, mobile hard disk, CD-ROM or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium may also be an integral part of the processor. The processor and the storage medium may be located in the ASIC. In addition, the ASIC may be located in the computing device. Of course, the processor and the storage medium may also exist as discrete components in the computing device.

A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing relevant hardware through a computer program. The program can be stored in a computer readable storage medium. When executed, it may include the procedures of the above-mentioned method embodiments. The aforementioned storage media include: ROM, RAM, magnetic disks, or optical disks and other media that can store program codes.

Claims

A method for link detection, characterized in that it comprises:

The first network device and the second network device negotiate a timeout period for establishing a bidirectional forwarding detection (BFD) session during the process of establishing an application layer session;

The first network device sets and starts a timer according to the negotiated timeout time, and establishes a bidirectional forwarding detection (BFD) session with the second network device;

If the establishment of the BFD session is not completed before the timer ends, the first network device interrupts the application layer session with the second network device.
The method of claim 1, wherein the method further comprises:

If the establishment of the BFD session has been completed before the timer ends, the first network device performs link detection through the BFD session.
The method according to claim 1 or 2, wherein the first network device and the second network device negotiate a timeout period for establishing a bidirectional forwarding detection (BFD) session during the process of establishing an application layer session, comprising:

The first network device and the second network device respectively carry a timeout period defined for the BFD session in a negotiation message for establishing the application layer session;

One of the timeout periods defined by the first network device and the second network device is selected as the timeout period of the BFD session.
The method of claim 3, wherein the first network device and the second network device are Border Gateway Protocol (BGP) nodes, and the first network device and the second network device are respectively establishing the application The negotiation message of the layer session carries the timeout time each defined for the BFD session, including:

After establishing a connection with the second network device, the first network device sends a first start (OPEN) message to the second network device, and receives a second OPEN message sent by the second network device The first OPEN message and the second OPEN message respectively carry the timeout time defined by the first network device and the second network device for the BFD session.
The method of claim 4, wherein the first OPEN message and the second OPEN message carry the timeout defined for the BFD session through a BFD enable field (BFD enable TLV) Time; the BFD-enable TLV includes a type, a length, and a value, and the timeout period defined for the BFD session is carried in the value of the BFD-enable TLV.
The method according to any one of claims 3-5, wherein the selecting one of the timeout periods defined by the first network device and the second network device as the timeout period of the BFD session comprises: The maximum time value is selected from the timeout time defined by the first network device and the second network device as the timeout time of the BFD session.
A network device, characterized by comprising:

The negotiation unit is used to negotiate the timeout period for establishing a bidirectional forwarding detection (BFD) session with the peer network device in the process of establishing an application layer session;

The BFD unit is configured to set and start a timer according to the timeout time negotiated by the negotiation unit, and establish a bidirectional forwarding detection (BFD) session with the peer network device;

The interrupting unit is configured to interrupt the application layer session with the peer network device when the BFD unit does not complete the establishment of the BFD session before the timer ends.
8. The network device according to claim 7, wherein if the establishment of the BFD session is completed before the timer ends, the BFD unit is further configured to perform link detection through the BFD session.
The network device according to claim 7 or 8, wherein the negotiation unit is specifically configured to send a timeout time defined by the local end for the BFD session to the opposite-end network device, and receive The timeout period defined by the peer network device for the BFD session sent by the device; the timeout period defined by the local end and the peer network device for the BFD session is carried in the negotiation message for establishing the application layer session in;

One of the timeout periods defined by the local end and the opposite end network device is selected as the timeout period of the BFD session.
The network device according to claim 9, wherein the network device and the opposite end network device are Border Gateway Protocol (BGP) nodes, and the negotiation unit is used to send the local end to the opposite end network device The timeout period defined for the BFD session and receiving the timeout period defined by the peer network device for the BFD session sent by the peer network device includes:

After establishing a connection with the opposite network device, the negotiation unit is configured to send a first start (OPEN) message to the opposite network device, and receive a second OPEN message sent by the opposite network device The first OPEN message and the second OPEN message respectively carry the timeout time defined by the network device and the opposite network device for the BFD session.
The network device according to claim 10, wherein the first OPEN message and the second OPEN message carry the definition for the BFD session through a BFD enable field (BFD enable TLV) Timeout period: The BFD-enable TLV includes a type, a length and a value, and the timeout period defined for the BFD session is carried in the value of the BFD-enable TLV.
11. The network device according to claims 9-11, wherein the negotiation unit is configured to select one of the timeout periods defined by the local and peer network devices as the timeout period of the BFD session, comprising: The negotiation unit is configured to select a maximum time value from the timeout time defined by the local end and the opposite end network device as the timeout time of the BFD session.
A network device is applied to a link detection system. The link detection system includes a first network device and a second network device. The network device is the first network device, and is characterized in that the network device includes processing The memory is used to store instructions; the processor is used to call instructions in the memory to execute the method according to any one of claims 1-6.
A computer non-transitory storage medium, wherein the computer non-transitory storage medium stores a computer program, wherein the computer program implements the method according to any one of claims 1 to 6 when the computer program is executed by a computing device.