CN110224886B

CN110224886B - Tunnel connectivity detection method and device and network edge equipment

Info

Publication number: CN110224886B
Application number: CN201910474458.3A
Authority: CN
Inventors: 郭威; 王伟
Original assignee: Hangzhou H3C Technologies Co Ltd
Current assignee: Hangzhou H3C Technologies Co Ltd
Priority date: 2019-05-31
Filing date: 2019-05-31
Publication date: 2021-02-09
Anticipated expiration: 2039-05-31
Also published as: CN110224886A

Abstract

The present disclosure provides a tunnel connectivity detection method, device and network edge device, relating to the technical field of network communication, the method includes: if the original topology path does not receive the BFD message sent by the second PE within the preset time, judging whether a virtual topology path of a BFD session is established between the first PE and the second PE; if so, establishing a BFD session for the original topology paths corresponding to the first PE and the second PE in a preset buffer period; and if the BFD session of the original topological path is established in the preset buffer period, forwarding the data message with the destination address of the second PE through the original topological path. The tunnel connectivity detection method, the tunnel connectivity detection device and the network edge equipment effectively avoid resource waste and flow interruption, can avoid redundant loss of flow, and provide reliable guarantee for stability and safety of key links in a network.

Description

Tunnel connectivity detection method and device and network edge equipment

Technical Field

The present disclosure relates to the field of network communication technologies, and in particular, to a method and an apparatus for detecting tunnel connectivity, and a network edge device.

Background

Generally, in order to achieve fast convergence of network failures and shorten flow interruption time caused by failures, a failure between network links must be detected quickly first, and a BFD (Bi-directional Forwarding Detection) Detection mechanism has become a mainstream technology for solving the above problems at present.

The method realizes the quick recovery of the fault IP network on the basis of quick fault detection, and is also important for realizing the high reliability of network services. The main solution to this problem in the industry at present is to calculate a backup route in advance, that is, when a router detects a fault, the router does not immediately diffuse routing information and perform route calculation, but replaces a primary route that has failed due to the fault with the backup route to directly repair the network fault, at this time, a routing protocol re-converges the route according to a new network topology, and the backup route is used to direct the forwarding of a packet until re-convergence is completed, so that the flow interruption time is greatly shortened, that is, the IP FRR technique.

The IP FRR technology is short for IP Fast route, it is proposed for satisfying the high route recovery speed, its basic principle is to establish a backup route for the link to be protected in the IP network, when the main link fails, the flow is switched to the backup link quickly, when the main link fails, the flow is switched back to the main link from the backup link, the application of this technology can reduce the loss of flow message when the network node or network link fails to happen to the maximum extent, and provide reliable guarantee for the stability and safety of the key link in the network.

Generally, for a network device that can form an IRR, when a BFD detection mechanism detects that a corresponding network link is disconnected, the network device can be quickly switched to a standby link through an IP FRR to send a BFD packet without BFD timeout. On the contrary, for a network device without an IP FRR, when a BFD detection mechanism detects a failure of a corresponding link, even if a standby link exists, the switching speed of the link is slow, so that a BFD response message received by a receiving end network device is slow, and the BFD response message is over time, the receiving end network device notifies an upper layer protocol that a PW (Pseudo Wire) state corresponding to the link is DWON, and when the link is switched, the BFD response message reaches the receiving end network device after going through the standby link, the receiving end network device notifies the upper layer protocol that the PW state is UP, and sometimes this repeated process may occur repeatedly many times, which causes a certain degree of network resource waste.

Disclosure of Invention

In view of this, an object of the present disclosure is to provide a method and an apparatus for detecting tunnel connectivity, and a network edge device, so as to improve the utilization rate of network resources.

In a first aspect, an embodiment of the present disclosure provides a method for detecting tunnel connectivity, where the method is applied to a first network edge device PE of a public network tunnel, where the public network tunnel further includes a second PE, and the method includes: if the original topology path does not receive the BFD message sent by the second PE within the preset time, judging whether a virtual topology path of a BFD session is established between the first PE and the second PE; the virtual topological path is created when a fast reroute (FRR) is not formed by a host route from the second PE to the first PE; if so, establishing a BFD session for the original topology paths corresponding to the first PE and the second PE in a preset buffer period; and if the BFD session of the original topological path is established in the preset buffer period, forwarding the data message with the destination address of the second PE through the original topological path.

With reference to the first aspect, an embodiment of the present disclosure provides a first possible implementation manner of the first aspect, where the creating a BFD session for an original topology path corresponding to a first PE and a second PE in a preset buffer period includes: and starting a timing function, and establishing a BFD session for the original topology path corresponding to the first PE and the second PE within the time length of the timing time length being less than the time length corresponding to the preset buffer period.

With reference to the first possible implementation manner of the first aspect, this disclosed implementation manner provides a second possible implementation manner of the first aspect, where the method further includes: if the timing time length reaches the time length corresponding to the set buffer period and the BFD session of the original topological path is not successfully established, stopping the timing of the buffer period; and setting the communication state of the first PE and the second PE as a DOWN state.

With reference to the first aspect, embodiments of the present disclosure provide a third possible implementation manner of the first aspect, where the method further includes: receiving a BFD message sent by the second PE; the BFD message is forwarded by the second PE by applying the original topological path, and carries a preset identifier which is used for representing that the fast reroute FRR is not formed from the second PE to the host route of the first PE; and creating a forwarding table of the virtual topological path corresponding to the first PE and the second PE, and creating a BFD session for the virtual topological path.

With reference to the third possible implementation manner of the first aspect, this disclosed implementation manner provides the third possible implementation manner of the first aspect, where the creating a BFD session for a virtual topological path includes: setting the link cost of the original topological path corresponding to the first PE and the second PE as a preset maximum value; and sending the BFD message to the second PE through an output port of the virtual topology path, so that the second PE replies the BFD message through the virtual topology path.

In a second aspect, an embodiment of the present disclosure further provides a method for detecting tunnel connectivity, where the method is applied to a second network edge device PE of a public network tunnel, where the public network tunnel further includes a first PE, and the method includes: when the original topological path is applied to send a BFD message to a first PE, detecting whether a host route from a second PE to the first PE forms a fast reroute (FRR); if not, sending a BFD message carrying a preset identifier to the first PE so that the first PE creates a forwarding table of a virtual topology path corresponding to the first PE and the second PE, and creates a BFD session for the virtual topology path; when the first PE does not receive the BFD message sent by the second PE by applying the original topology path within the preset time, the BFD session is established for the original topology path corresponding to the first PE and the second PE within the preset buffer period, and the data message with the destination address of the second PE is forwarded through the original topology path.

In a third aspect, an embodiment of the present disclosure further provides a device for detecting tunnel connectivity, where the device is applied to a first network edge device PE of a public network tunnel, and the public network tunnel further includes a second PE, and the device includes: the judging module is used for judging whether a virtual topology path of a BFD session is established between the first PE and the second PE if the original topology path does not receive the BFD message sent by the second PE within the preset time; the virtual topological path is created when a fast reroute (FRR) is not formed by a host route from the second PE to the first PE; the first creating module is used for creating a BFD session for the original topology path corresponding to the first PE and the second PE in a preset buffer period when the judgment result of the judging module is yes; and the forwarding module is used for forwarding the data message with the destination address as the second PE through the original topological path if the BFD session of the original topological path is established in a preset buffer period.

With reference to the third aspect, the present disclosure provides a first possible implementation manner of the third aspect, where the first creating module is configured to: and starting a timing function, and establishing a BFD session for the original topology path corresponding to the first PE and the second PE within the time length of the timing time length being less than the time length corresponding to the preset buffer period.

With reference to the first possible implementation manner of the third aspect, the present disclosure provides a second possible implementation manner of the third aspect, where the apparatus further includes: and the setting module is used for setting the communication state between the first PE and the second PE to be a DOWN state if the timing duration reaches the set duration corresponding to the buffer period and the BFD session of the original topological path is not established successfully.

With reference to the third aspect, the present disclosure provides a third possible implementation manner of the third aspect, where the apparatus further includes: the receiving module is used for receiving the BFD message sent by the second PE; the BFD message is forwarded by the second PE by applying the original topological path, and carries a preset identifier which is used for representing that the fast reroute FRR is not formed from the second PE to the host route of the first PE; and the second creating module is used for creating a forwarding table of the virtual topology path corresponding to the first PE and the second PE, and creating a BFD session for the virtual topology path.

With reference to the third possible implementation manner of the third aspect, this disclosed implementation manner provides a fourth possible implementation manner of the third aspect, where the second creating module is further configured to: setting the link cost of the original topological path corresponding to the first PE and the second PE as a preset maximum value; and sending the BFD message to the second PE through an output port of the virtual topology path, so that the second PE replies the BFD message through the virtual topology path.

In a fourth aspect, an embodiment of the present disclosure further provides a device for detecting tunnel connectivity, where the device is applied to a second network edge device PE of a public network tunnel, and the public network tunnel further includes a first PE, and the device includes: the detection module is used for detecting whether a host route from a second PE to a first PE forms a fast reroute (FRR) when the original topological path is applied and BFD messages are sent to the first PE; the first sending module is used for sending a BFD message carrying a preset identifier to the first PE when the detection result of the detection module is negative, so that the first PE creates a forwarding table of a virtual topology path corresponding to the first PE and the second PE, and creates a BFD session for the virtual topology path; and the second sending module is used for creating a BFD session for the original topology path corresponding to the first PE and the second PE in a preset buffer period when the first PE does not receive the BFD message sent by the original topology path applied by the second PE within a preset time, and forwarding the data message with the destination address of the second PE through the original topology path.

In a fifth aspect, the disclosed embodiments also provide a network edge device comprising a processor and a memory, the memory storing machine executable instructions capable of being executed by the processor, the processor executing the machine executable instructions to implement the method of the first aspect or the second aspect.

In a sixth aspect, the disclosed embodiments also provide a machine-readable storage medium having stored thereon machine-executable instructions which, when invoked and executed by a processor, cause the processor to carry out the method of the first or second aspect.

The tunnel connectivity detection method, apparatus and network edge device provided by the embodiments of the present disclosure enable a first network edge device PE in a public network tunnel to determine whether there is a virtual topology path that has created a BFD session with a second PE when an original topology does not receive a BFD packet sent by the second PE within a predetermined time, and create a BFD session for the original topology path corresponding to the first PE and the second PE within a preset buffer period when the virtual topology path exists, and if the BFD session is created completely, continue to forward a data packet having a destination address of the second PE through the original topology path, during the buffer period, the BFD session of the original topology path does not report a delay fault to an upper layer protocol, and can avoid a false alarm phenomenon of a BFD session mechanism to a certain extent, so as to maintain a connection state between the first PE and the second PE to effectively avoid waste of resources and interruption of flow, and the caused redundant loss of the flow provides reliable guarantee for the stability and the safety of a key link in the network.

Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the disclosure. The objectives and other advantages of the disclosure will be realized and attained by the structure particularly pointed out in the written description and drawings.

In order to make the aforementioned objects, features and advantages of the present disclosure more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic diagram of a networking provided in an embodiment of the present disclosure;

fig. 2 is a flowchart of a tunnel connectivity detection method according to an embodiment of the present disclosure;

fig. 3 is a schematic diagram of another networking provided by the embodiments of the present disclosure;

fig. 4 is a flowchart of another tunnel connectivity detection method provided in the embodiments of the present disclosure;

fig. 5 is a schematic structural diagram of a tunnel connectivity detection apparatus according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of another tunnel connectivity detection apparatus provided in the embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of another tunnel connectivity detection apparatus provided in the embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of a network edge device according to an embodiment of the present disclosure.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the embodiments of the present disclosure will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are some, but not all embodiments of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

Generally, in order to realize rapid detection of network failures, a BFD detection mechanism is mostly adopted, which is a standardized, interface medium-independent, upper-layer protocol-independent, general rapid failure detection technology, and can rapidly detect failures of bidirectional forwarding paths between two devices and provide millisecond detection.

For convenience of understanding, fig. 1 shows a networking schematic diagram, as shown in fig. 1, where CE1 and CE2 are Customer Network side devices (Customer Edge), referred to as CE devices for short, and PE-A, PE-B, PE-C, PE-D are Provider Network side devices (Provider Edge), referred to as PE devices for short, connected to the CE devices for short, and the PE devices are mainly responsible for accessing a VPN (Virtual Private Network) service, and completing mapping and forwarding of a packet from a user Network to a public Network tunnel and from the public Network tunnel to the user Network, where the number in the diagram is an overhead of an IGP (Interior Gateway Protocol).

In actual use, the CE device and the PE device are connected through an AC (access Circuit), and the PE device are connected through a PW, where the AC is a physical Circuit or a Virtual Circuit connecting the CE device and the PE device, such as a DLCI (Data Link Connection Identifier) of a Frame Relay Protocol (Frame Relay Protocol), a VPI (Virtual Path Identifier)/VCI (Virtual Channel Identifier) of an ATM (Asynchronous Transfer Mode), an Ethernet interface (Ethernet interface), a VLAN (Virtual Local Area Network), a PPP (Point to Point Protocol) Connection on a physical interface, and the like. Further, the PW is a virtual bidirectional connection between two PE devices, for example, an MPLS (Multiprotocol Label Switching) PW is composed of a pair of unidirectional LSPs (Label Switched paths) in opposite directions.

It should be understood that the networking form shown in fig. 1 is only a schematic diagram, and only two CE devices and one PE device are shown, and in an actual application, the networking may also have other forms, where a physical circuit or a virtual circuit used in the networking form may also be a device according to an actual use situation, which is not limited in this embodiment of the present invention.

Based on the networking form shown in fig. 1, it is assumed that during the establishment of a Virtual Private Lan Service (VPLS), PE-D and PE-A, PE-B establish a primary PW and a secondary PW, where PE-a is primary, PE-B is secondary, and PE-A, PE-B is a layered VPLS, and a terminal PE-C is connected, that is, for PE-A, PE-B, only one PW is located on the left side of PE-D, and only one PW is located on the right side of PE-C. Thus, the overhead of IGP, labeled numerically in FIG. 1, and the standard of acyclic theory for FRR, PE-D to PE-A host routing cannot form a standard IP FRR, whereas PE-A to PE-D host routing can.

In order to realize fast link switching, in fig. 1, for a public network TUNNEL LSP, BFD is configured, for example, when a PW is established by a Label Distribution Protocol (LDP) method, in some cases, a tunel-based BFD is configured, for example, PE-D to PE-a, and a reverse PE-a to PE-D, and both the tunel BFD are configured, and when the BFD is DOWN, the entire tunel is considered to be unavailable, so as to perform PW switching. In fig. 1, when the link between PE-a and PE-D is disconnected, for PE-a, if the BFD message sent by PE-a to PE-D does not respond, since the PE-a side can form IP FRR, the PE-a to PE-D side switches to the standby link quickly, for PE-D, the received BFD message is normal, no timeout of TUNNEL BFD occurs, but conversely, for PE-D to PE-a side, since IP FRR is not formed before, the switching speed of the link is slower, so that the BFD response message sent by PE-D to PE-a is slower, which results in slow reception of BFD message by PE-a and possibly timeout of detection of message by PE-a side, and if the BFD message by PE-a side times out, the PE-a switches to PW, the current PW state may be made unavailable, however, PE-a has only one PW, which may result in traffic failure. In practice, however, in the networking shown in fig. 1, a backup link is still available, and the handover is slow, and at this time, the upper layer protocol should not be directly notified that the PW is unavailable. Subsequently, when the routing switching is finished, the BFD message goes through the backup link, so that when the PW is UP again, the upper layer protocol is informed that the PW is available, and thus, the repeated process not only consumes resources but also may cause redundant loss of flow.

Based on this, the tunnel connectivity detection method, apparatus and network edge device provided in the embodiments of the present disclosure can effectively alleviate the above problems.

For the convenience of understanding the present embodiment, a detailed description will be first given of a tunnel connectivity detection method provided in the embodiments of the present disclosure.

In a possible embodiment, the present disclosure provides a tunnel connectivity detection method, where the method is applied to a first network edge device PE of a public network tunnel, and in actual use, the public network tunnel further includes a second PE, where the first PE is generally a network edge device that establishes a service and a BFD session with the second PE in networking of the public network tunnel. Specifically, as shown in fig. 2, a flowchart of a tunnel connectivity detection method includes the following steps:

step S202, if the original topology path does not receive the BFD message sent by the second PE within the preset time, judging whether a virtual topology path of a BFD session is established between the first PE and the second PE;

the virtual topological path is created when a fast reroute (FRR) is not formed by a host route from the second PE to the first PE; specifically, the virtual topology path is generally regarded as a virtual topology path, and when there is the virtual topology path of the created BFD session between the first PE and the second PE, it may indicate that there is another path available between the first PE and the second PE, so that the BFD session does not report a delay fault by the upper layer protocol, but continues to execute step S204 to re-create the BFD session for the original topology path.

In actual use, the second PE may serve as a receiving end of a BFD packet, so that when receiving the BFD packet sent by the first PE, a response is made; further, the second PE may also be in an active mode, and after the BFD session is established, the BFD packet is actively sent to the first PE, which may be specifically set according to an actual use condition, and this is not limited in this disclosure.

Step S204, if yes, BFD conversation is established for the original topological paths corresponding to the first PE and the second PE in a preset buffer period;

in general, the connection state between the first PE and the second PE is maintained as UP during the preset buffer period, so that the upper layer protocol cannot sense these actions when creating a BFD session for the original topology path corresponding to the first PE and the second PE.

Step S206, if the BFD session of the original topology path is created in the preset buffer period, the data packet with the destination address as the second PE is forwarded through the original topology path.

Generally, according to the existing method, if a BFD message is not received within a preset time, the established BFD session recognizes that a network failure occurs in the link, and notifies the upper layer protocol of the failure of the link, and the upper layer protocol performs failure processing according to the reported failure information, for example, notifies that PW between the first PE and the second PE is DOWN, and so on.

Through the processes of the steps S202 to S206, if the BFD packet sent by the second PE is not received within the preset time, the preset buffer period is started to time, instead of reporting the network fault to the upper layer protocol. At this time, the host routing may be recalculated according to the original topology path, and generate a new BFD packet forwarding link, and when it is detected that a new link is generated in the original topology path within a preset buffer period, a new and stable BFD transceiving relationship may be continuously established, and then the service between the first PE and the second PE may be continuously performed, that is, the tunnel connectivity detected during the entire buffer period is in an UP state, and the unavailability of the service may not be notified.

The tunnel connectivity detection method provided by the embodiment of the present disclosure can determine whether a virtual topology path for creating a BFD session exists between a first network edge device PE and a second PE when a first network edge device PE in a public network tunnel applies an original topology to receive no BFD packet sent by the second PE within a predetermined time, and create a BFD session for the original topology path corresponding to the first PE and the second PE within a preset buffer period when the virtual topology path exists, and if the BFD session is created completely, continue forwarding a data packet with a destination address of the second PE through the original topology path, during the buffer period, the BFD session of the original topology path does not report a delay fault to an upper layer protocol, and can avoid a false alarm phenomenon of a BFD session mechanism to a certain extent, so as to maintain a connection state between the first PE and the second PE to be UP, thereby effectively avoiding waste of resources and interruption of flow, and the caused redundant loss of the flow provides reliable guarantee for the stability and the safety of a key link in the network.

In actual use, in step S204, a timing procedure is started in the procedure of creating the BFD session for the original topology path within a preset buffer period, so as to create the BFD session within the set time, and avoid a situation that the service flow is affected due to the fact that the first PE and the second PE cannot communicate for a long time. Therefore, in step S204, the step of creating a BFD session for the original topology path corresponding to the first PE and the second PE in the preset buffer period includes: and starting a timing function, and establishing a BFD session for the original topology path corresponding to the first PE and the second PE within the time length of the timing time length being less than the time length corresponding to the preset buffer period.

Further, if the timed duration reaches a set duration corresponding to the buffer period and the BFD session of the original topology path is not successfully created, setting the communication state between the first PE and the second PE to be a DOWN state, that is, the preset buffer period may be implemented in a timed manner, and during the timed period, maintaining the communication state between the first PE and the second PE to be an UP; if the BFD session of the original topological path is established in the timing period, continuing to forward the data message with the destination address as the second PE through the original topological path, and stopping timing; if the timing duration reaches the set duration corresponding to the buffer period and the BFD session of the original topological path is not successfully created, reporting a fault to an upper-layer protocol, and simultaneously stopping the timing function. In actual use, the corresponding duration of the buffering period may be configured according to an actual situation, which is not limited in the embodiment of the present disclosure.

In actual use, the virtual topology path is usually pre-established, for example, the virtual topology path may be created at an initial stage of establishing a network where the first PE and the second PE are located, or the virtual topology path may be created at a time of initially establishing a BFD session between the first PE and the second PE. The method can be specifically set according to the actual use condition, and the real-time mode of the disclosure does not limit the method.

In a specific implementation, the process of establishing the virtual topology path may include the following steps:

(1) receiving a BFD message sent by the second PE; the BFD message is forwarded by the second PE by applying an original topological path, and carries a preset identifier which is used for representing that a fast reroute (FRR) is not formed from the second PE to a host route of the first PE;

specifically, when the second PE sends a BFD packet to the first PE, it may be calculated first whether a fast reroute FRR can be formed from the current host route from the second PE to the first PE, and if it cannot be formed, a non-backup identifier, that is, a preset identifier, may be added to the FLAG field of the BFD control message, so that the BFD packet sent to the first PE carries the preset identifier, and the first PE is informed of the fact that the second PE cannot form the FRR.

(2) And creating a forwarding table of the virtual topological path corresponding to the first PE and the second PE, and creating a BFD session for the virtual topological path.

Specifically, the process of creating the forwarding table of the virtual topology path may also indicate that other paths are available between the first PE and the second PE.

In actual use, the preset identifier carried by the BFD message sent by the second PE may be carried in the BFD message when the second PE sends the BFD message to the first PE for the first time after the BFD session is established; or when the second PE equipment is restarted, if a BFD session is established, sending a BFD message carrying a preset identifier to the first PE; or, after the BFD session is established, the BFD packet carrying the preset identifier may be periodically sent according to a preset period or duration, and a specific sending form may be set according to an actual use condition, which is not limited in the embodiment of the present disclosure.

Further, the fast reroute FRR, also referred to as an IP FRR, is usually a redundant backup link established for some key links or nodes to be protected under a normal network condition, and when a failure occurs, it is only required to quickly switch the traffic to the backup link, therefore, the IP FRR needs to additionally perform calculation to create a backup route, and meanwhile, a backup next hop needs to be calculated for the link to be protected according to a standard of a theory without a ring during calculation, the next hop needs to be ring-free in the whole network, and the generated route forwarding table entry has both the main next hop and the backup next hop, at this time, the network normally forwards the packet by using the main next hop, when a failure occurs, the traffic is switched to the backup next hop for forwarding, and before the new route completely converges, the traffic is forwarded by using the backup route.

Therefore, for each PE device forming a network, it is capable of knowing the trend of the whole path to a certain destination, i.e. knowing the ability of backup next hop, so that after calculating that an IP FRR can be formed, it can be switched to the backup link quickly after the main link is disconnected. Therefore, when the second PE sends the response BFD packet to the first PE, it may perform a routing calculation to determine whether the FRR can be formed.

Further, the virtual topology path is usually created based on a multi-topology routing technology, and in order to implement network interworking, the multi-topology routing technology may divide a physical topology in a certain networking into a plurality of logical topologies, where the logical topologies may be crossed or overlapped, and different topologies operate respective routing computations, so that an optimal path individually belonging to one destination address in each logical network may be formed, and a respective independent routing table or a forwarding table may be formed.

The virtual topology path is generally a topology path formed by any backup path in a logic network, when a multi-topology routing technology is used in a fast rerouting application, a global topology can be used as an active network, and then after receiving a BFD packet carrying a preset identifier sent by a second PE, a forwarding table of the virtual topology path corresponding to the first PE and the second PE can be created based on the global topology in the current networking.

In specific implementation, a topology path corresponding to a main network is equivalent to an original topology path, a BFD message generated by a BFD session is forwarded through the original topology path under normal conditions, and when the BFD message sent by a second PE based on the original topology path fails to reach the first PE in time, it is determined whether a virtual topology path for creating the BFD session exists between the first PE and the second PE.

Specifically, the step of creating the BFD session for the virtual topology path includes the following steps:

(1) setting the link cost of the original topological path corresponding to the first PE and the second PE to be a preset maximum value;

specifically, the link of the original topology path corresponding to the first PE and the second PE refers to a link in the virtual topology path that is the same as the link corresponding to the original topology path between the first PE and the second PE, for example, based on the networking shown in fig. 1, if the link from PE-D to PE-a in the original topology path is L1, when a BFD session is created for the virtual topology path, the link overhead of the link from PE-D to PE-a in the original topology path L1 is set to a preset maximum value, so as to avoid that when the BFD session is created in the virtual topology path, the sent BFD packet is forwarded again according to the original topology path to form a routing loop, which results in flow interruption.

(2) And sending the BFD message to the second PE through an output port of the virtual topology path, so that the second PE replies the BFD message through the virtual topology path.

Specifically, because the BFD session created in the virtual topology path is also a bidirectional forwarding detection mechanism established between the first PE and the second PE, the BFD packet sent by the first PE to the second PE through the egress port of the virtual topology path will also encapsulate a source address and a destination address, and the source address and the destination address are the same as the source address and the destination address of the BFD packet sent through the original topology path, that is, after the link cost of the original topology path corresponding to the first PE and the second PE is set to the preset maximum value, the BFD packet with the same source and destination protocols is continuously sent through the virtual topology path, and the BFD session is created for the virtual topology path.

In practical use, the first PE is generally a network edge device that can form an FRR, that is, the main link where the first PE is located has a backup link, so that when the main link fails, traffic can be quickly switched to the backup link, and when the main link fails and recovers, traffic can be switched back to the main link from the backup link.

Further, since the original topology path usually corresponds to a main link in the network and is usually an optimal path for a destination address, if the BFD session of the original topology path can be recreated and completed during the buffering period, the data packet with the destination address as the second PE can be continuously forwarded through the original topology path, so as to ensure reliable operation of the service.

In addition, since the virtual topological path is a topological path that can be formed based on any backup network in the logical network, the new link calculated by the original topological path usually coincides with the path of the link corresponding to the virtual topological path; if the BFD message in the original topology path is not received and transmitted on time when the timing duration reaches the duration corresponding to the set buffer period, the buffer period can be forcibly ended and an upper layer protocol is notified, and further the communication state between the first PE and the second PE is set to be a DOWN state.

Specifically, for convenience of understanding, on the basis of the form shown in fig. 1, fig. 3 shows another networking form, as shown in fig. 3, and also taking the example that the networking includes two CE devices and four PE devices, it is described that, specifically, it is assumed that PE-D, PE-A, PE-B is one segment to establish traffic and a BFD session, and PE-A, PE-B, PE-C is another segment to establish traffic and a BFD session, and PE-D, PE-A, PE-B is taken as an example for explanation, and a host route of PE-a is configured with a fast reroute FRR, and a host route of PE-D is not configured with a fast reroute FRR, based on the networking form shown in fig. 3, a process of the tunnel connectivity detection method provided by the embodiment of the present disclosure is as follows:

(1) the PE-A establishes PW TUNNEL BFD to the PE-D, and the PE-D judges that the destination address 1.1.1.1/32 of the return path cannot form FRR when responding to a BFD message, so that the BFD message responded by the PE-D carries a preset identifier to represent that the host route from the PE-D to the PE-A is not configured with a fast reroute FRR;

(2) after receiving the BFD packet carrying the preset identifier, PE-a analyzes the packet, creates a virtual topology path corresponding to PE-a and PE-D, and a forwarding table of the virtual topology path, and creates a BFD session for the virtual topology path for forwarding the BFD packet, meanwhile, as shown in fig. 3, in the forwarding table of the virtual topology path, the optimal path to reach the destination address of destination 1.1.1.1/32 is set to the maximum cost value from the cost of next hop L1, so that the BFD packet corresponding to PE-D needs to go through other links, for example, L2 link in fig. 3;

(3) after receiving the BFD packet with the preset identifier, PE-a also sets the overhead of the next hop L1 of the main path to PE-D of 4.4.4.4 to the maximum value, so that the BFD packet goes through the L3 link shown in fig. 3, and finally establishes a BFD session, that is, based on the networking form shown in fig. 3, the virtual topology path is L2+ L3, and the original topology path is L1;

under the normal condition of the link, the PE-A and the PE-D establish the BFD session by using L1, and the virtual topological path of L2+ L3 is equivalent to a virtual topological path which is not enabled when L1 is normal.

(4) When a link of an original networking topology path L1 really fails, a BFD message received by a PE-A end in the original topology path is overtime, and because the BFD in the virtual topology path can be established, a BFD session does not report PW DOWN between the PE-A and the PE-D to an upper layer protocol, considers that the PW is still available at the moment, and enters a buffer period to start a timing function;

(5) during a buffering period, namely, within a time length that is shorter than a preset time length corresponding to the buffering period, in an original topological path, due to a fault of an L1 link, recalculation can be performed according to a route, and due to the fact that a master-slave relationship is established for PE-A and PE-B when networking is established, in the original topological path, an L1 link is switched to an L3 link, and retransmission and receiving of BFD messages are continued, at the moment, the recalculated route in the original extension path is overlapped with the route corresponding to the virtual topological path, and if BFD session establishment is completed in the overlapped path, the buffering period is ended, and the timing of the buffering period is stopped;

(6) if the BFD session in the overlapped path is not successfully established, the BFD session reports a fault to an upper layer protocol, and the upper layer protocol sets the state of the PW at the moment to be a DOWN state.

In the buffer period stage, the BFD session does not report the fault condition by the upper layer protocol, and when the timing duration reaches the corresponding duration of the set buffer period and the BFD session of the original topology path is not successfully created, the fault condition is reported so as to report the fault only when the network is truly unavailable, thereby avoiding BFD oscillation and a large amount of flow break caused by routing switching in some scenes, avoiding redundant loss of flow, and providing reliable guarantee for stability and safety of the key link in the network.

It should be understood that the foregoing embodiment is described in the context of networking shown in fig. 1 or fig. 3, and in actual use, the tunnel connectivity detection method provided by the embodiment of the present disclosure is also applicable to similar tunnel technologies such as L3VPN/EVPN/L2VPN, and may be specifically set according to the actual use, which is not limited by the embodiment of the present disclosure.

In addition, another tunnel connectivity detection method is provided in the embodiments of the present disclosure, where the method is applied to a second network edge device PE of a public network tunnel, where the public network tunnel further includes a first PE, and in actual use, the second network edge device PE is generally a network edge device that establishes a service and a BFD session with the first PE, and specifically, as shown in fig. 4, a flowchart of another tunnel connectivity detection method includes the following steps:

step S402, when the original topological path is applied to send BFD message to the first PE, detecting whether the host route from the second PE to the first PE forms a fast reroute FRR;

the first PE is usually a network edge device corresponding to the second PE, and after the first PE and the second PE establish a BFD session, a BFD packet may be sent between the first PE and the second PE to detect whether a link between the first PE and the second PE fails.

Step S404, if not, sending a BFD message carrying a preset identifier to the first PE, so that the first PE creates a forwarding table of a virtual topology path corresponding to the first PE and the second PE, and creates a BFD session for the virtual topology path;

step S406, when the first PE does not receive the BFD packet sent by the second PE using the original topology path within the preset time, a BFD session is created for the original topology path corresponding to the first PE and the second PE within a preset buffer period, and the data packet with the destination address of the second PE is forwarded through the original topology path.

Specifically, the preset identifier is used to represent that a fast reroute FRR is not formed from a host route from the second PE to the first PE, so that the first PE creates a forwarding table of the virtual topology path after receiving the BFD packet and analyzing the preset identifier.

The tunnel connectivity detection method provided by the embodiment of the disclosure can detect whether the host route of the second PE can form a fast reroute FRR when the second PE sends a BFD packet, and when the FRR is not formed, the BFD message carrying the preset identification is responded to the first PE, and then the first PE creates a forwarding table of the corresponding virtual topology path, when the first PE does not receive the BFD message of the second PE within the preset time, a BFD session is created for the original topological paths corresponding to the first PE and the second PE in a preset buffer period, and the data message with the destination address of the second PE is forwarded through the original topological path, thereby avoiding the fault condition reported to an upper layer protocol when the first PE does not receive the BFD message of the second PE within the preset time, realizing the control from the BFD session, preventing the false report of the BFD session, meanwhile, the redundant loss of the flow can be avoided, and reliable guarantee is provided for the stability and safety of the key link in the network.

Corresponding to the tunnel connectivity detection method shown in fig. 2, an embodiment of the present disclosure further provides a tunnel connectivity detection apparatus, where the apparatus is applied to a first network edge device PE of a public network tunnel, where the public network tunnel further includes a second PE, and as shown in fig. 5, the apparatus includes:

the determining module 50 is configured to determine whether a virtual topology path for creating a BFD session exists between the first PE and the second PE if the original topology path does not receive the BFD packet sent by the second PE within a preset time; the virtual topological path is created when a fast reroute (FRR) is not formed by a host route from the second PE to the first PE;

a first creating module 52, configured to create, when the determination result of the determining module is yes, a BFD session for the original topology path corresponding to the first PE and the second PE in a preset buffer period;

a forwarding module 54, configured to forward, if the BFD session of the original topology path is created in the preset buffer period, the data packet with the destination address as the second PE through the original topology path.

Specifically, the first creating module is configured to: and starting a timing function, and establishing a BFD session for the original topology path corresponding to the first PE and the second PE within the time length of the timing time length being less than the time length corresponding to the preset buffer period.

Based on fig. 5, fig. 6 shows a schematic structural diagram of another tunnel connectivity detection apparatus, which includes, in addition to the structure shown in fig. 5:

and a setting module 56, configured to set a communication state between the first PE and the second PE to be a DOWN state if the timing duration reaches a duration corresponding to the set buffer period and the BFD session of the original topology path is not successfully created.

A receiving module 58, configured to receive a BFD packet sent by the second PE; the BFD message is forwarded by the second PE by applying the original topological path, and carries a preset identifier which is used for representing that the fast reroute FRR is not formed from the second PE to the host route of the first PE;

a second creating module 60, configured to create a forwarding table of the virtual topology path corresponding to the first PE and the second PE, and create a BFD session for the virtual topology path.

Further, the second creating module is further configured to: setting the link cost of the original topological path corresponding to the first PE and the second PE as a preset maximum value; and sending the BFD message to the second PE through an output port of the virtual topology path, so that the second PE replies the BFD message through the virtual topology path.

In addition, corresponding to the tunnel connectivity detection method shown in fig. 4, the embodiment of the present disclosure further provides another tunnel connectivity detection apparatus, where the apparatus is applied to a second network edge device PE of a public network tunnel, where the public network tunnel further includes a first PE, and as shown in fig. 7, the apparatus includes:

a detecting module 70, configured to detect whether a host route from a second PE to a first PE forms a fast reroute FRR when a BFD packet is sent to the first PE by using an original topology route;

a first sending module 72, configured to send a BFD packet carrying a preset identifier to the first PE when the detection result of the detection module is negative, so that the first PE creates a forwarding table of a virtual topology path corresponding to the first PE and the second PE, and creates a BFD session for the virtual topology path;

a second sending module 74, configured to, when the first PE does not receive the BFD packet sent by the second PE by using the original topology path within the preset time, create a BFD session for the original topology path corresponding to the first PE and the second PE within a preset buffer period, and forward the data packet with the destination address of the second PE through the original topology path.

The tunnel connectivity detection device provided by the embodiment of the present disclosure has the same technical features as the tunnel connectivity detection method provided by the above embodiment, so that the same technical problems can be solved, and the same technical effects can be achieved.

The embodiment of the present disclosure further provides a network edge device, which includes a processor and a memory, where the memory stores machine executable instructions capable of being executed by the processor, and the processor executes the machine executable instructions to implement the above tunnel connectivity detection method.

Further, the disclosed embodiments also provide a machine-readable storage medium storing machine-executable instructions, which when called and executed by a processor, cause the processor to implement the above tunnel connectivity detection method.

Referring to fig. 8, an embodiment of the present disclosure further provides a schematic structural diagram of a network edge device, including: a processor 800, a memory 801, a bus 802 and a communication interface 803, the processor 800, the communication interface 803 and the memory 801 being connected by the bus 802; the processor 800 is used to execute executable modules, such as computer programs, stored in the memory 801.

The Memory 801 may include a high-speed Random Access Memory (RAM) and may also include a non-volatile Memory (non-volatile Memory), such as at least one disk Memory. The communication connection between the network element of the system and at least one other network element is realized through at least one communication interface 803 (which may be wired or wireless), and the internet, a wide area network, a local network, a metropolitan area network, and the like can be used.

Bus 802 can be an ISA bus, PCI bus, EISA bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one double-headed arrow is shown in FIG. 8, but that does not indicate only one bus or one type of bus.

The memory 801 is used for storing a program, and the processor 800 executes the program after receiving an execution instruction, and the method executed by the tunnel connectivity detection apparatus disclosed by any of the foregoing embodiments of the present disclosure may be applied to the processor 800, or implemented by the processor 800.

The processor 800 may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 800. The Processor 800 may be a general-purpose Processor, and includes a Central Processing Unit (CPU), a Network Processor (NP), and the like; the device can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components. The various methods, steps, and logic blocks disclosed in the embodiments of the present disclosure may be implemented or performed. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of the method disclosed in connection with the embodiments of the present disclosure may be directly implemented by a hardware decoding processor, or implemented by a combination of hardware and software modules in the decoding processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 801, and the processor 800 reads the information in the memory 801 and completes the steps of the method in combination with the hardware thereof.

The tunnel connectivity detection method, apparatus and computer program product of the network edge device provided in the embodiments of the present disclosure include a computer-readable storage medium storing program codes, where instructions included in the program codes may be used to execute the method described in the foregoing method embodiments, and specific implementation may refer to the method embodiments, and will not be described herein again.

Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Finally, it should be noted that: the above embodiments are merely specific embodiments of the present disclosure, which are intended to illustrate rather than limit the technical solutions of the present disclosure, and the scope of the present disclosure is not limited thereto, and although the present disclosure is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive of the technical solutions described in the foregoing embodiments or equivalent technical features thereof within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present disclosure, and should be construed as being included therein. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A tunnel connectivity detection method is applied to a first network edge (PE) of a public network tunnel, wherein the public network tunnel further comprises a second PE, and the method comprises the following steps:

if the original topology path does not receive the BFD message sent by the second PE within the preset time, judging whether a virtual topology path of a BFD session is established between the first PE and the second PE; wherein the virtual topology path is created when a fast reroute (FRR) is not formed by a host route from the second PE to the first PE;

if so, establishing a BFD session for the original topology path corresponding to the first PE and the second PE in a preset buffer period;

and if the BFD session of the original topological path is established in the preset buffer period, forwarding a data message with a destination address of the second PE through the original topological path.

2. The method according to claim 1, wherein the step of creating a BFD session for the original topology path corresponding to the first PE and the second PE within a preset buffer period comprises:

and starting a timing function, and establishing a BFD session for the original topology path corresponding to the first PE and the second PE within the time length of timing less than the time length corresponding to a preset buffer period.

3. The method of claim 2, further comprising:

and if the timing duration reaches the set duration corresponding to the buffer period and the BFD session of the original topological path is not successfully established, setting the communication state between the first PE and the second PE to be a DOWN state.

4. The method of claim 1, further comprising:

receiving a BFD message sent by the second PE; the BFD message is forwarded by the second PE by applying an original topological path, and carries a preset identifier which is used for representing that a fast reroute (FRR) is not formed from the second PE to a host route of the first PE;

creating a forwarding table of a virtual topology path corresponding to the first PE and the second PE, and creating a BFD session for the virtual topology path.

5. The method of claim 4, wherein the step of creating a BFD session for the virtual topological path comprises:

setting the link cost of the original topological path corresponding to the first PE and the second PE to be a preset maximum value;

and sending a BFD message to the second PE through an output port of the virtual topology path, so that the second PE replies the BFD message through the virtual topology path.

6. A tunnel connectivity detection method is applied to a second network edge device (PE) of a public network tunnel, wherein the public network tunnel further comprises a first PE, and the method comprises the following steps:

when an original topological path is applied to send a BFD message to a first PE, detecting whether a host route from a second PE to the first PE forms a fast reroute (FRR);

if not, sending a BFD message carrying a preset identifier to the first PE so that the first PE creates a forwarding table of a virtual topology path corresponding to the first PE and the second PE, and creates a BFD session for the virtual topology path; the preset identification is used for representing that a fast reroute (FRR) is not formed by host routes from the second PE to the first PE;

and when the first PE does not receive the BFD message sent by the second PE by applying the original topology path within the preset time, judging whether a virtual topology path for creating the BFD session exists between the first PE and the second PE, if so, creating the BFD session for the original topology path corresponding to the first PE and the second PE within a preset buffer period, and forwarding a data message with a destination address of the second PE through the original topology path.

7. A tunnel connectivity detection apparatus, applied to a first network edge device (PE) of a public network tunnel, the public network tunnel further including a second PE, the apparatus comprising:

the judging module is used for judging whether a virtual topology path of a BFD session is established between the first PE and the second PE if the original topology path does not receive a BFD message sent by the second PE within a preset time; wherein the virtual topology path is created when a fast reroute (FRR) is not formed by a host route from the second PE to the first PE;

a first creating module, configured to create, when the determination result of the determining module is yes, a BFD session for the original topology path corresponding to the first PE and the second PE in a preset buffer period;

and the forwarding module is used for forwarding the data message with the destination address as the second PE through the original topological path if the BFD session of the original topological path is established in a preset buffer period.

8. The apparatus of claim 7, wherein the first creation module is configured to:

9. The apparatus of claim 8, further comprising:

and the setting module is used for setting the communication state between the first PE and the second PE to be a DOWN state if the timing duration reaches the set duration corresponding to the buffer period and the BFD session of the original topological path is not successfully established.

10. The apparatus of claim 7, further comprising:

a receiving module, configured to receive a BFD packet sent by the second PE; the BFD message is forwarded by the second PE by applying an original topological path, and carries a preset identifier which is used for representing that a fast reroute (FRR) is not formed from the second PE to a host route of the first PE;

and the second creating module is used for creating a forwarding table of the virtual topology path corresponding to the first PE and the second PE, and creating a BFD session for the virtual topology path.

11. The apparatus of claim 10, wherein the second creation module is further configured to:

12. A tunnel connectivity detection apparatus, applied to a second network edge device (PE) of a public network tunnel, the public network tunnel further including a first PE, the apparatus comprising:

the detection module is used for detecting whether a host route from the second PE to the first PE forms a fast reroute (FRR) when the original topological path is applied and BFD messages are sent to the first PE;

a first sending module, configured to send a BFD packet carrying a preset identifier to the first PE when the detection result of the detection module is negative, so that the first PE creates a forwarding table of a virtual topology path corresponding to the first PE and the second PE, and creates a BFD session for the virtual topology path; the preset identification is used for representing that a fast reroute (FRR) is not formed by host routes from the second PE to the first PE;

a second sending module, configured to, when the first PE does not receive a BFD packet sent by the second PE by using the original topology path within a preset time, determine whether there is a virtual topology path between the first PE and the second PE where a BFD session has been created, if so, create a BFD session for the original topology path corresponding to the first PE and the second PE within a preset buffer period, and forward a data packet with a destination address of the second PE through the original topology path.

13. A network edge device comprising a processor and a memory, the memory storing machine executable instructions executable by the processor, the processor executing the machine executable instructions to implement the method of any one of claims 1 to 6.

14. A machine-readable storage medium having stored thereon machine-executable instructions which, when invoked and executed by a processor, cause the processor to implement the method of any of claims 1 to 6.