A method, device and medium for specifying an sbfd backhaul path in an mpls network

Abstract

The application discloses a method, device and medium for specifying an SBFD backhaul path in an MPLS network, and belongs to the field of communication technologies, to further solve the technical problem that the existing method for specifying an SBFD backhaul path causes communication obstacles between devices of different manufacturers on the basis of solving the problem that traffic cannot be quickly switched to a backup path when a primary LSP fails. The method comprises the following steps: sending an MPLS echo request message to a reflection end, wherein the MPLS echo request message comprises a local descriptor of a transmitting end, a local IP address of the transmitting end, an SBFD backhaul tunnel ID and a primary-backup path flag; after receiving a first reply message corresponding to the MPLS echo request message, if the first reply message is an error-free code message, sending an SBFD detection message to the reflection end. The application realizes that traffic can be quickly switched to a backup path when a primary LSP fails, and realizes communication between devices of different manufacturers, so that there are no communication obstacles between devices of different manufacturers.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication technology, and in particular to a method, device and medium for specifying an SBFD backhaul path in an MPLS network. BACKGROUND

[0002] Compared with the traditional Bidirectional Forwarding Detection (BFD), Seamless Bidirectional Forwarding Detection (SBFD) realizes faster and more reliable path monitoring by simplifying the process and reducing resource consumption. SBFD is divided into a transmitting end and a reflecting end. The transmitting end actively sends SBFD detection packets, and the reflecting end replies to the detection packets sent by the transmitting end after receiving them. In SBFD, only the transmitting end needs to run a state machine, maintain a state, and perform fault alarm, and the reflecting end does not need a state machine, but only needs to receive, process, and feedback packets from the transmitting end.

[0003] SBFD can be applied in a Multi-Protocol Label Switch (MPLS) network. The tunnel from the transmitting end to the reflecting end includes a primary Label Switched Path (LSP) and a backup LSP. When the SBFD detects that the primary LSP in the tunnel has a fault, the transmitting end establishes SBFD for the backup LSP, and switches traffic to the backup path when the backup LSP is detected to be fault-free.

[0004] Since the reflecting end can match multiple sessions initiated by the transmitting end, it cannot uniquely correspond to a path. Therefore, the backhaul of the reflecting end packet is IP routing forwarding, that is, the path through which the transmitting end sends the SBFD detection packet to the reflecting end is the SBFD linkage scene path (LSP), and the path through which the reflecting end replies to the SBFD detection packet from the transmitting end (backhaul path) is the IP routing forwarding path.

[0005] That is, no matter whether the transmitting end establishes the SBFD on the primary LSP or the standby LSP, the backhaul path from the reflecting end to the transmitting end is an IP routing forwarding path. If the IP routing forwarding path from the reflecting end to the transmitting end is the reverse path of the primary LSP, no matter whether the transmitting end establishes the SBFD on the primary LSP or the standby LSP, the backhaul path is the reverse path of the primary LSP. In this way, when the primary LSP fails, the transmitting end establishes the SBFD on the primary LSP, detects the failure and alarms; the transmitting end establishes the SBFD on the standby LSP, and since the backhaul path is the reverse path of the primary LSP, the failure is still detected and alarms; that is, the primary LSP and the standby LSP are both detected as a failure state and alarms. When the IP routing forwarding path from the reflecting end to the transmitting end switches to the reverse path of the standby LSP, the traffic can walk on the standby LSP again, which causes the traffic to be unable to quickly switch to the standby path when the primary LSP path fails, resulting in long-time packet loss of the traffic.

[0006] In the prior art closest to the present application, the solution to the above problem is to specify the SBFD backhaul path. For the SBFD established on the primary LSP, the backhaul path adopts the reverse path of the primary LSP; for the SBFD established on the standby LSP, the backhaul path adopts the reverse path of the standby LSP.

[0007] The specific implementation is that the linkage between the SBFD and the backhaul tunnel is determined and managed according to the binding label allocated by the administrator: the binding label is configured on the forward tunnel from the transmitting end to the reflecting end and the backhaul tunnel from the reflecting end to the transmitting end, and the binding labels of the forward tunnel and the backhaul tunnel are consistent. The SBFD detection packet of the transmitting end carries the binding label of the forward tunnel and the primary / standby path flag, and the reflecting end receives the packet, determines the backhaul tunnel matched with the binding label of the forward tunnel according to the binding label in the packet, and determines whether the backhaul tunnel adopts the reverse path of the primary LSP or the reverse path of the standby LSP according to the primary / standby path flag in the packet.

[0008] The implementation mode has the following technical defects: in a first aspect, the implementation mode needs to configure a binding label for the forward tunnel and the backhaul tunnel in advance, and the SBFD detection packet needs to be adapted to the encapsulation of the binding label of the tunnel, and the SBFD detection packet adapted to the binding label is a non-standard packet, so that the interoperability and compatibility between devices of different manufacturers are poor, and communication barriers exist between devices, and the devices cannot be connected and communicated smoothly. In a second aspect, the primary and backup path flag carried in the SBFD detection packet is consistent with the path of the transmitting end to the reflecting end for sending the SBFD detection packet, that is, the transmitting end uses the primary LSP, and the primary and backup path flag indicates the primary LSP, and the backhaul path of the reflecting end is the reverse path of the primary LSP, the transmitting end uses the backup LSP, and the primary and backup path flag indicates the backup LSP, and the backhaul path of the reflecting end is the reverse path of the backup LSP, and the flexibility of specifying the backhaul path is poor, and is only suitable for symmetric networking, and is not suitable for asymmetric networking. In a third aspect, the SBFD detection packet adapted to the binding label has a high implementation difficulty in determining the backhaul tunnel matched with the binding label through the binding label in the SBFD detection packet at the reflecting end. SUMMARY

[0009] The application provides a method, device and medium for specifying an SBFD backhaul path in an MPLS network, to further solve the technical problem that the existing method for specifying an SBFD backhaul path configures a binding label for a tunnel between a transmitting end and a reflecting end, and a SBFD detection packet adapted to the binding label of the tunnel is a non-standard packet, which causes communication barriers between devices of different manufacturers.

[0010] In a first aspect, the application provides a method for specifying an SBFD backhaul path in an MPLS network, characterized in that the method is applied to a transmitting end, and the method comprises:

[0011] sending an MPLS echo request packet to a reflecting end, wherein the MPLS echo request packet comprises a local descriptor of the transmitting end, a local IP address of the transmitting end, an SBFD backhaul tunnel ID and a primary and backup path flag, and the primary and backup path flag is used to indicate a primary LSP or a backup LSP;

[0012] after receiving a first reply packet corresponding to the MPLS echo request packet, if the first reply packet is an error-free code packet, sending an SBFD detection packet to the reflecting end.

[0013] In a feasible implementation mode, before sending the MPLS echo request packet to the reflecting end, the method further comprises:

[0014] determining the local descriptor of the transmitting end as the value of BFD_TLV in the MPLS echo request message, determining the SBFD backhaul tunnel ID as the value of BFD Reverse Path Tunnel ID SubTLV Type in the MPLS echo request message, and determining the primary-backup path flag as the value of BFD Reverse Path LSP Flag Sub TLV Type in the MPLS echo request message.

[0015] In an available implementation, after sending the MPLS echo request message to the reflecting end, the method further comprises:

[0016] After receiving the first reply message corresponding to the MPLS echo request message, if the first reply message is an error code message, prompting configuration error information, and continuing to send the MPLS echo request message to the reflecting end;

[0017] If the first reply message corresponding to the MPLS echo request message is not received, continuing to send the MPLS echo request message to the reflecting end.

[0018] In a second aspect, the application provides a method for specifying an SBFD backhaul path in an MPLS network, characterized in that the method is applied to a reflecting end, and the method comprises:

[0019] receiving an MPLS echo request message sent by a transmitting end, determining the local descriptor of the transmitting end in the MPLS echo request message as a remote descriptor, determining the local descriptor of the transmitting end in the MPLS echo request message as a target IP address, generating a backhaul table item, and recording the remote descriptor, the target IP address, and the SBFD backhaul tunnel ID and the primary-backup path flag in the MPLS echo request message in the backhaul table item;

[0020] returning a first reply message corresponding to the MPLS echo request message to the transmitting end;

[0021] receiving an SBFD detection message sent by the transmitting end, determining the local IP address in the SBFD detection message as a target IP address of the SBFD session, and determining the local descriptor in the SBFD detection message as a remote descriptor of the SBFD session;

[0022] determining, in the backhaul table entry, an SBFD backhaul tunnel ID and a primary / backup path flag corresponding to the SBFD session according to the target IP address of the SBFD session and the remote descriptor of the SBFD session, and determining a target backhaul path according to the SBFD backhaul tunnel ID and the primary / backup path flag corresponding to the SBFD session;

[0023] returning, to the transmitting end, a second reply message corresponding to the SBFD detection message according to the target backhaul path.

[0024] In an implementation, after the backhaul table entry is generated, the method further includes:

[0025] starting an aging timer corresponding to the MPLS echo request message, the aging timer being used to start timing from returning, to the transmitting end, a first reply message corresponding to the MPLS echo request message, and deleting, after a timing time of the aging timer reaches a preset time length, the remote descriptor, the target IP address, the SBFD backhaul tunnel ID and the primary / backup path flag corresponding to the MPLS echo request message in the backhaul table entry.

[0026] In an implementation, after returning, to the transmitting end, a second reply message corresponding to the SBFD detection message, the method further includes:

[0027] adjusting an aging timer corresponding to the SBFD session to restart timing from returning, to the transmitting end, a second reply message corresponding to the SBFD detection message.

[0028] In an implementation, after determining, in the SBFD detection message, a local IP address as a target IP address of the SBFD session and a local descriptor as a remote descriptor of the SBFD session, the method further includes:

[0029] if the SBFD backhaul tunnel ID and the primary / backup path flag corresponding to the SBFD session do not exist in the backhaul table entry, returning, to the transmitting end, a second reply message corresponding to the SBFD detection message according to a dynamic IP routing path from the reflecting end to the transmitting end.

[0030] In an implementation, after receiving the SBFD detection message sent by the transmitting end, the method further includes returning, to the transmitting end, a second reply message corresponding to the SBFD detection message according to a preset static IP routing path from the reflecting end to the transmitting end.

[0031] In a third aspect, the present application provides a device for specifying an SBFD backhaul path in an MPLS network, the device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method for specifying an SBFD backhaul path in an MPLS network according to any of the above embodiments.

[0032] In a fourth aspect, the present application provides a non-volatile computer storage medium, which is a non-volatile computer readable storage medium storing at least one program, each of the programs comprising instructions that, when executed by a terminal, cause the terminal to perform the method for specifying an SBFD backhaul path in an MPLS network according to any of the above embodiments.

[0033] The method, device and medium for specifying an SBFD backhaul path in an MPLS network provided by the present application have the following beneficial technical effects compared with the prior art:

[0034] (1) In the present application, the reflection end generates a backhaul table item by using the local descriptor of the transmitting end, the local IP address of the transmitting end, the SBFD backhaul tunnel ID and the primary-backup path flag in the MPLS echo request message sent by the transmitting end, and determines the backhaul tunnel ID and the primary-backup path flag corresponding to the SBFD detection message in the backhaul table item by using the remote descriptor and the target IP address after receiving the SBFD detection message, and then determines the target backhaul path by using the backhaul tunnel ID and the primary-backup path flag. The present application realizes that the traffic can be quickly switched to the backup path when the primary LSP fails by using the above method, and the MPLS echo request message and the SBFD detection message used in the present application are both standard messages, which can realize the communication between devices of different manufacturers, so that there is no communication obstacle between devices of different manufacturers, and the interoperability and compatibility can be ensured.

[0035] (2) In the present application, the primary-backup path flag in the MPLS echo request message can be consistent with the path used by the transmitting end to send the SBFD detection message, or can be inconsistent with the path used by the transmitting end to send the SBFD detection message, so that the flexibility of specifying the SBFD backhaul path is high, the adaptability is wide, and the present application is applicable to symmetric networking and asymmetric networking.

[0036] (3) In the present application, the transmitting end analyzes the MPLS echo message and the SBFD detection message to determine the target backhaul path, which has a lower difficulty and is easier to implement. BRIEF DESCRIPTION OF DRAWINGS

[0037] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0038] Figure 1 A schematic diagram of an SBFD session negotiation process in the related art;

[0039] Figure 2 A schematic diagram of an SBFD transmitter state machine in the related art;

[0040] Figure 3 A schematic diagram of an SBFD reflector and transmitter matching in the related art;

[0041] Figure 4 A schematic diagram of a path between an SBFD transmitter and reflector in the related art;

[0042] Figure 5 A schematic diagram of traffic path switching before and after a primary LSP failure in the related art;

[0043] Figure 6 A schematic diagram of an SBFD backhaul path in the related art;

[0044] Figure 7 A flowchart of a method for specifying an SBFD backhaul path in an MPLS network according to the present application;

[0045] Figure 8 A flowchart of another method for specifying an SBFD backhaul path in an MPLS network according to the present application;

[0046] Figure 9 A session diagram of a transmitter and reflector according to the present application;

[0047] Figure 10 A schematic diagram of a device for specifying an SBFD backhaul path in an MPLS network according to an embodiment of the present application. DETAILED DESCRIPTION

[0048] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below with reference to the embodiments thereof and the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0049] Compared with the traditional BFD, the SBFD realizes faster and more reliable path monitoring by simplifying the process and reducing resource consumption. Figure 1 FIG. 1 is a schematic diagram of an SBFD session negotiation process in the related art. Figure 1 As shown in the figure, the SBFD is divided into a transmitting end and a reflecting end, wherein the transmitting end actively sends SBFD detection packets to the reflecting end, and the reflecting end passively replies to the SBFD detection packets after receiving the packets sent by the transmitting end.

[0050] In the SBFD, only the transmitting end needs to run a state machine, maintain a state, and perform fault alarm, and the reflecting end does not need a state machine, and is only responsible for receiving, processing, and feeding back packets from the transmitting end. Figure 2 FIG. 2 is a schematic diagram of an SBFD transmitting end state machine in the related art. Figure 2 As shown in the figure, the SBFD packet is first sent by the transmitting end to the reflecting end, and the initial state of the transmitting end is Down. The transmitting end sets the local state to Up after receiving the Up packet returned by the reflecting end. The transmitting end sets the state to Down after receiving the Admin Down packet returned by the reflecting end. The transmitting end sets the state to Down if the returned packet is not received before the timer expires. If the Up packet returned by the reflecting end is received when the transmitting end is in the Up state, the local state is maintained in the Up state. If the Admin Down packet returned by the reflecting end is received or the returned packet is not received before the timer expires when the transmitting end is in the Down state, the local state is maintained in the Down state.

[0051] The SBFD can be applied to an MPLS network, the tunnel from the transmitting end to the reflecting end includes a primary label switched path (LSP) and a backup LSP, and the transmitting end establishes the SBFD for the primary LSP and the backup LSP. When the SBFD detects that the primary LSP in the tunnel fails, the transmitting end is expected to quickly detect the failure and switch the traffic to the backup LSP.

[0052] Since the reflecting end can match multiple sessions initiated by the transmitting end, it cannot uniquely correspond to a path, and therefore the reflecting end packet return is IP routing forwarding, that is, the path from the transmitting end to the reflecting end for sending the SBFD detection packet is the SBFD linkage scene path (LSP), and the path (return path) from the reflecting end to the transmitting end for replying to the SBFD detection packet is the IP routing forwarding path. Figure 3 FIG. 4 is a matching diagram of the SBFD reflecting end and the transmitting end in the related art. Figure 3As shown, the reflecting endpoint D can match sessions initiated by three transmitters: transmitter A, transmitter B, and transmitter C. The local descriptor of the session from transmitter A to reflecting endpoint D is 8001, and the remote descriptor is 100; the local descriptor of the session from transmitter B to reflecting endpoint D is 8002, and the remote descriptor is 100; the local descriptor of the session from transmitter C to reflecting endpoint D is 8001, and the remote descriptor is 100. On transmitter D, there is only a local descriptor of 100. Since the local descriptor of the reflecting endpoint cannot uniquely correspond to a path, the return path from reflecting endpoint D to transmitters A, B, and C adopts the IP routing forwarding path.

[0053] In other words, regardless of whether the transmitter establishes SBFD on the primary LSP or the backup LSP, the return path from the reflector to the transmitter is always an IP routing forwarding path. If the IP routing forwarding path from the reflector to the transmitter is the reverse path of the primary LSP, the return path will always be the reverse path of the primary LSP, regardless of whether the transmitter establishes SBFD on the primary LSP or the backup LSP. Therefore, when the primary LSP fails, the transmitter will detect the fault and trigger an alarm when establishing SBFD on the primary LSP; similarly, when establishing SBFD on the backup LSP, the transmitter will still detect the fault and trigger an alarm because the return path is the primary LSP's return path. That is, both the primary and backup LSPs are detected as faulty and trigger alarms. Only when the IP routing forwarding path from the reflector to the transmitter switches to the reverse path of the backup LSP can traffic re-pass through the backup LSP. This results in traffic not being able to quickly switch to the backup path when the primary LSP path fails, causing prolonged packet loss.

[0054] For example, Figure 4 This is a schematic diagram of the path between the transmitter and reflector of an SBFD in related technologies, such as... Figure 4 As shown, the primary LSP for the tunnel from transmitter PE1 to reflector PE2 is transmitter PE1 → device P1 → device P2 → transmitter PE2, and the backup LSP is transmitter PE1 → device P4 → device P3 → transmitter PE2. The IP routing path from transmitter PE2 to transmitter PE1 is transmitter PE2 → device P2 → device P1 → transmitter PE1. Transmitter PE1 establishes SBFDs for both the primary and backup LSPs. The forwarding path of the SBFD from transmitter PE1 to reflector PE2 follows the bound LSP, and the return path from reflector PE2 to transmitter PE1 follows the IP routing path.

[0055] Figure 5 This is a schematic diagram illustrating the traffic path switching before and after a primary LSP failure in related technologies, such as... Figure 5As shown, the traffic goes through the primary LSP before the primary LSP fails; when the primary LSP fails, for example, a link or a P device in the primary LSP fails, the transmitting end PE1 is expected to quickly detect the failure and switch the data traffic to the backup LSP. However, because the SBFD backhaul goes through the IP routing path (the reflecting end PE2->device P2->device P1->transmitting end PE1), that is, the reverse path of the primary LSP, and the primary LSP fails, at this time, the SBFD bound to the primary LSP and the backup LSP will detect the failure, and neither of the two paths is available.

[0056] When the IP routing path from the reflecting end PE2 to the transmitting end PE1 is switched to the reflecting end PE2->device P3->device P4->transmitting end PE1, that is, the backhaul path is the reverse path of the backup LSP, the SBFD bound to the backup LSP disappears, and the traffic goes through the backup LSP again.

[0057] In the prior art, the technical solutions to solve the above problems include:

[0058] (1) Accelerate the routing switching speed from the reflecting end PE2 to the transmitting end PE1, configure the IP BFD between the transmitting end PE1 and the device P1, the device P1 and the device P2, and the device P2 and the reflecting end PE2, and link the BFD, when one of them fails, accelerate the routing convergence.

[0059] (2) The administrator makes the backhaul path on the backup path through the configuration of routing weight or other methods, when the primary LSP is disconnected, the backup LSP passes through the SBFD without failure, and can still be quickly switched.

[0060] (3) Specify the SBFD backhaul path, for the SBFD established on the primary LSP, the backhaul path adopts the reverse path of the primary LSP; for the SBFD established on the backup LSP, the backhaul path adopts the reverse path of the backup LSP.

[0061] Among them, the closest prior art to the present application is to specify the SBFD backhaul path, for the SBFD established on the primary LSP, the backhaul path adopts the reverse path of the primary LSP; for the SBFD established on the backup LSP, the backhaul path adopts the reverse path of the backup LSP.

[0062] The specific implementation is to determine and manage the linkage between the SBFD and the backhaul tunnel according to the binding label allocated by the administrator.

[0063] Exemplarily, Figure 6For a schematic diagram of a related art method of specifying an SBFD backhaul path, a forward tunnel Tunnel 1 from a transmitting end PE1 to a reflecting end PE2 and a backhaul tunnel Tunnel 2 from the reflecting end PE2 to the transmitting end PE1 are respectively configured with a binding label, and the binding labels of the forward tunnel Tunnel 1 and the backhaul tunnel Tunnel 2 are consistent. The SBFD detection packet of the transmitting end PE1 carries the binding label X configured by the forward tunnel Tunnel 1 and a primary-backup path flag. After receiving the packet, the reflecting end PE2 determines the backhaul tunnel Tunnel 2 matched with the binding label X according to the binding label X of the forward tunnel Tunnel 1 in the packet, and determines whether the backhaul tunnel adopts the reverse path of the primary LSP or the reverse path of the backup LSP according to the primary-backup path flag in the packet.

[0064] The above implementation has the following technical defects: First, the implementation needs to pre-configure the binding labels for the forward tunnel and the backhaul tunnel, and the SBFD detection packet needs to be adapted to the encapsulation of the binding label of the tunnel. The SBFD detection packet adapted to the binding label is a non-standard packet, which makes the interoperability and compatibility between devices of different manufacturers poor, resulting in communication obstacles between devices and unable to smoothly connect and communicate. Second, the primary-backup path flag carried in the SBFD detection packet is consistent with the path of the SBFD detection packet sent from the transmitting end to the reflecting end, that is, if the transmitting end adopts the primary LSP, the primary-backup path flag indicates the primary LSP, and the backhaul path of the reflecting end is the reverse path of the primary LSP; if the transmitting end adopts the backup LSP, the primary-backup path flag indicates the backup LSP, and the backhaul path of the reflecting end is the reverse path of the backup LSP. The flexibility of specifying the backhaul path is poor, which is only applicable to symmetric networking and not applicable to asymmetric networking. Third, the implementation of determining the backhaul tunnel matched with the binding label in the reflecting end through the binding label in the SBFD detection packet is difficult.

[0065] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings.

[0066] Figure 7 A flowchart of a method of specifying an SBFD backhaul path in an MPLS network is provided by the present application, and the method is applied to a transmitting end. As shown in the figure, the method comprises the following execution steps: Figure 7

[0067] S701, an MPLS echo request packet is sent to a reflecting end.

[0068] The MPLS echo request packet comprises a local descriptor of the transmitting end, a local IP address of the transmitting end, an SBFD backhaul tunnel ID and a primary-backup path flag.

[0069] ​The transmitting end in the application first sends an MPLS echo request message to the reflecting end before sending the SBFD detection message to the reflecting end. The MPLS echo request message in the application is a standard message, and can also be called an MPLS Ping message.

[0070] The local end descriptor of the transmitting end in the MPLS echo request message refers to the local end descriptor of the transmitting end in the subsequent SBFD session.

[0071] The SBFD backhaul tunnel ID in the MPLS echo request message is an identifier of a backhaul tunnel used in the subsequent SBFD session and specified for the reflecting end by the transmitting end, that is, the reflecting end is instructed to return the reply message corresponding to the SBFD detection message through the tunnel corresponding to the ID in the subsequent SBFD session.

[0072] The primary and backup path flag in the MPLS echo request message is used to indicate a primary LSP or a backup LSP. When it is expected that the reflecting end returns the reply message of the SBFD detection message using the reverse path of the primary LSP in the backhaul tunnel in the subsequent SBFD session, the primary and backup path flag is configured as the primary LSP. When it is expected that the reflecting end returns the reply message of the SBFD detection message using the reverse path of the backup LSP in the backhaul tunnel in the subsequent SBFD session, the primary and backup path flag is configured as the backup LSP.

[0073] As a possible implementation manner, before sending the MPLS echo request message to the reflecting end, the method further comprises: determining the local end descriptor of the transmitting end as the value of BFD_TLV in the MPLS echo request message, determining the SBFD backhaul tunnel ID as the value of BFD Reverse Path Tunnel ID Sub TLV Type in the MPLS echo request message, and determining the primary and backup path flag as the value of BFD Reverse Path LSP Flag Sub TLV Type in the MPLS echo request message.

[0074] Among them, BFD Reverse Path Tunnel ID Sub TLV Type and BFD Reverse Path LSP Flag Sub TLV Type are two sub-TLVs in BFD Reverse Path TLV Type.

[0075] In the related art, BFD_TLV (15) has been applied in the BFD dynamic learning descriptor, and draft-ietf-mpls-bfd-directed-19 defines the TLV related content of the BFD dynamic learning descriptor to specify the backhaul. The TLV defined in the present application is not exactly the same as that defined in the above draft.

[0076] Table 1 is an example of an MPLS echo request message provided by the present application. As shown in Table 1, MPLS echo common is a regular part in the MPLS echo request message, and the local IP address of the transmitting end is configured in the regular part.

[0077] The BFD discriminator in the MPLS echo request message is used to indicate the local descriptor of the transmitting end, and is a value (Value) corresponding to Type BFD TLV. In the present example, the local descriptor of the transmitting end is 500.

[0078] The Reverse Path Tunnel ID in the MPLS echo request message is used to indicate the SBFD backhaul tunnel ID, and is a value (Value) corresponding to Type BFD Reverse Path Tunnel ID Sub TLV Type. In the present example, the SBFD backhaul tunnel ID is 2.

[0079] The Reverse Path LSP Primary or Backup Flag in the MPLS echo request message is used to indicate the primary and backup path flag, and is a value (Value) corresponding to Type BFD Reverse Path LSP Flag Sub TLV Type. In the present example, 0 indicates the primary LSP, and 1 indicates the backup LSP.

[0080] Table 1 is an example of an MPLS echo request message provided by the present application. As shown in Table 1, MPLS echo common is a regular part in the MPLS echo request message, and the local IP address of the transmitting end is configured in the regular part.

[0081]

[0082] S702、In the present application, after receiving the first reply message corresponding to the MPLS echo request message, if the first reply message is an error-free code message, an SBFD detection message is sent to the reflecting end.

[0083] In the present application, the SBFD detection message includes an SBFD message and an SBFD-ECHO message.

[0084] In the application, the first reply message corresponding to the MPLS echo request message is received at the transmitting end, and the first reply message is a no-error code message, which indicates that the reflecting end has successfully received the MPLS echo request message, and the local descriptor of the transmitting end, the local IP address of the transmitting end, the SBFD backhaul tunnel ID and the primary-backup path flag in the MPLS echo request message are received. At this time, the SBFD detection message is sent to the transmitting end.

[0085] It should be noted that the SBFD detection message in the application is a standard message, which includes the local IP address of the transmitting end and the local descriptor of the transmitting end.

[0086] As a possible implementation manner, after the MPLS echo request message is sent to the reflecting end, the method further includes: after the first reply message corresponding to the MPLS echo request message is received, if the first reply message is an error code message, the configuration error information is prompted, and the MPLS echo request message is continuously sent to the reflecting end; if the first reply message corresponding to the MPLS echo request message is not received, the MPLS echo request message is continuously sent to the reflecting end.

[0087] In some embodiments, if the transmitting end generates an alarm after sending the SBFD detection message to the reflecting end, the MPLS echo request message is re-sent to the reflecting end.

[0088] Figure 8 A flowchart of another method for specifying an SBFD backhaul path in an MPLS network provided by the application is provided, and the method is applied to a reflecting end. As shown in the figure, the method includes the following execution steps: Figure 8

[0089] S801, receiving the MPLS echo request message sent by the transmitting end, determining the local descriptor of the transmitting end in the MPLS echo request message as a remote descriptor, determining the local IP address of the transmitting end in the MPLS echo request message as a target IP address, and generating a backhaul table item.

[0090] The backhaul table item is used to record the remote descriptor, the target IP address, and the SBFD backhaul tunnel ID and the primary-backup path flag in the MPLS echo request message, and the four have a corresponding relationship.

[0091] ​For example, after receiving the MPLS echo request message shown in Table 1, the reflecting end determines the local descriptor (BFD discriminator) of the transmitting end in the MPLS echo request message as the remote descriptor, that is, it determines 500 as the remote descriptor; the reflecting end determines the local IP address of the transmitting end in the MPLS echo request message (assumed to be 1.1.1.1) as the target IP address, that is, it determines 1.1.1.1 as the target IP address.

[0092] Table 2 is an example of a return entry provided by the present invention. As shown in Table 2, the return entry includes the target IP address (1.1.1.1), the remote descriptor (500), and the SBFD return tunnel ID (2) and primary / backup path flag (primary LSP) corresponding to the target IP address (1.1.1.1) and the remote descriptor (500).

[0093] Table 2. Example of a return trip entry

[0094]

[0095] In some embodiments, if no LSP path exists, the primary path return is used by default; that is, if the primary / backup path flag does not exist, the primary / backup path flag is set to the primary LSP.

[0096] S802. Return the first reply message corresponding to the MPLS echo request message to the transmitter.

[0097] In this invention, after receiving the MPLS echo request message and recording the remote descriptor, target IP address, SBFD backhaul tunnel ID, and primary / backup path flag in the MPLS echo request message in the backhaul table, the reflecting end returns the first reply message corresponding to the MPLS echo request message to the transmitting end so that the transmitting end is aware of the above situation.

[0098] S803. Receive the SBFD detection message sent by the transmitter, determine the local IP address in the SBFD detection message as the target IP address of the SBFD session, and determine the local descriptor in the SBFD detection message as the remote descriptor of the SBFD session.

[0099] In this invention, the SBFD detection message is a standard message, which includes the local IP address of the transmitter and the local descriptor of the transmitter.

[0100] For example, assuming that the local IP address in the SBFD detection packet is 1.1.1.1, the reflection end determines 1.1.1.1 as the target IP address of the SBFD session corresponding to the SBFD detection packet; and assuming that the local descriptor in the SBFD detection packet is 500, the reflection end determines 500 as the remote descriptor of the SBFD session.

[0101] S804, determining the SBFD backhaul tunnel ID and the main / standby path flag corresponding to the SBFD session in the backhaul table item according to the target IP address of the SBFD session and the remote descriptor of the SBFD session, and determining the target backhaul path according to the SBFD backhaul tunnel ID and the main / standby path flag corresponding to the SBFD session.

[0102] As described in the above example, the target IP address of the SBFD session is 1.1.1.1, and the remote descriptor of the SBFD session is 500, so that, through the two parameters of the target IP address and the remote descriptor of the SBFD session, the SBFD backhaul tunnel ID corresponding to the SBFD session is determined as 2, and the main / standby path flag is determined as the main LSP in the backhaul table item as shown in Figure 2 According to the SBFD backhaul tunnel ID, the target backhaul path can be determined as the path in the tunnel with the tunnel ID of 2; further, according to the main / standby path flag, the target backhaul path is the main LSP in the tunnel with the tunnel ID of 2, that is, the reverse path of the main LSP in the tunnel from the emission end to the reflection end.

[0103] It should be noted that the main / standby path flag in the MPLS echo request packet of the present application can be set according to actual needs, which can be consistent with the path used when the emission end sends the SBFD detection packet to the reflection end, or can be inconsistent. Specifically, when the emission end sends the SBFD detection packet to the reflection end, the main LSP is used, and the main / standby path flag can be the main LSP, that is, the reflection end can use the reverse path of the main LSP when returning the second reply packet; or the main / standby path flag can be the standby path flag, that is, the reflection end can use the reverse path of the standby LSP when returning the second reply packet.

[0104] In this way, the method for specifying the SBFD backhaul path in the MPLS network provided by the present application is suitable for both symmetric networking and asymmetric networking, and has better flexibility.

[0105] S805, returning the second reply packet corresponding to the SBFD detection packet to the emission end according to the target backhaul path.

[0106] After the target backhaul path is determined, the reflection end uses the target backhaul path determined through the target IP address and the remote descriptor in the backhaul table entry when returning the second reply message corresponding to the SBFD detection message to the transmission end.

[0107] It can be understood that, after receiving the SBFD detection message, the reflection end in the application can exchange IP addresses, descriptors, UDP port numbers, etc. according to the existing technology bag, encapsulate the second reply message corresponding to the SBFD detection message, and determine the target backhaul path according to the above method after encapsulating the second reply message.

[0108] As a possible implementation manner, after the backhaul table entry is generated, the method further includes: starting an aging timer corresponding to the MPLS echo message, the aging timer is used to start timing from returning the first reply message corresponding to the MPLS echo request message to the transmission end, and deleting the remote descriptor, the target IP address, the SBFD backhaul tunnel ID and the primary and backup path flag corresponding to the MPLS echo message in the backhaul table entry after the timing time of the aging timer reaches a preset time length.

[0109] The remote descriptor, the target IP address, the SBFD backhaul tunnel ID and the primary and backup path flag corresponding to the MPLS echo request message in the backhaul table entry are used to determine the tunnel and path used for returning the second reply message corresponding to the SBFD detection message after the corresponding SBFD detection message is received, and if the SBFD detection message corresponding to the MPLS echo request message is not received after a preset time length, it is considered that the remote descriptor, the target IP address, the SBFD backhaul tunnel ID and the primary and backup path flag corresponding to the MPLS echo request message in the backhaul table entry are no longer used. In order to avoid that the above data which is no longer used occupies space, the above data is deleted at this time.

[0110] As a possible implementation manner, after returning the second reply message corresponding to the SBFD detection message to the transmission end, the method further includes:

[0111] Adjusting the aging timer corresponding to the SBFD session to restart timing from returning the second reply message corresponding to the SBFD detection message to the transmission end.

[0112] After the reflection end in the application receives the SBFD detection message corresponding to the SBFD session, the remote descriptor, the target IP address, the SBFD backhaul tunnel ID and the primary and backup path flag corresponding to the SBFD session in the backhaul table entry have been used, at this time, the data is continuously retained, the aging timer corresponding to the SBFD session is refreshed, the timing time of the aging timer corresponding to the SBFD session is cleared, and the timing is restarted.

[0113] That is, after determining the target IP address and remote descriptor of the SBFD session according to the SBFD detection packet, and determining the SBFD backhaul tunnel ID and primary / backup path flag corresponding to the SBFD session in the backhaul table item according to the target IP address and remote descriptor of the SBFD session, the data in the backhaul table item are reserved, and the aging timer corresponding to the data restarts timing.

[0114] After the aging timer corresponding to the SBFD session restarts timing, when the timing duration of the aging timer does not reach a preset duration, the data corresponding to the SBFD session in the backhaul table item are still reserved, and can be used in subsequent SBFD sessions.

[0115] As a possible implementation, after determining the local IP address in the SBFD detection packet as the target IP address of the SBFD session and determining the local descriptor in the SBFD detection packet as the remote descriptor of the SBFD session, the method further comprises: if the SBFD backhaul tunnel ID and the primary / backup path flag corresponding to the SBFD session do not exist in the backhaul table item, returning a second reply packet corresponding to the SBFD detection packet to the transmitting end according to a dynamic IP routing path from the reflecting end to the transmitting end.

[0116] As a possible implementation, in addition to the above method of determining the target backhaul path through the backhaul table item, the application can also specify the backhaul path used by the reflecting end to return the second reply packet corresponding to the SBFD detection packet to the transmitting end through a static IP path. That is, after receiving the SBFD detection packet sent by the transmitting end, returning the second reply packet corresponding to the SBFD detection packet to the transmitting end according to a preset static IP routing path from the reflecting end to the transmitting end.

[0117] For example, the transmitting end is configured with a static SBFD for MPLS TE LSP, the local descriptor is 500, the remote descriptor is a descriptor 16843009 (0x01010101) generated according to the opposite IP address 1.1.1.1, the primary path of the MPLS TE tunnel 1 is bound, and the local IP address is 2.2.2.2, as shown below:

[0118] sbfd local-discriminator 500

[0119] remote-discriminator 1.1.1.1

[0120] enable mpls-te 1 lsp primary

[0121] Reflective egress configuration static route: ip REMOTE_IP_ADDRESS (sbfd | bfd | sbfd-echo) remote-discriminator BFD_DISCRIMINATOR mpls-te TUNNEL_ID lsp (primary | backup)

[0122] For example, for IP packet with destination address 2.2.2.2 and SBFD packet with your-discriminator 500, specify the primary path of MPLS TE tunnel 2: ip 2.2.2.2 sbfd remote-discriminator 500 mpls-te 2 lsp primary.

[0123] For example, for IP packet with destination address 2.2.2.2 and SBFD- ECHO packet with your-discriminator 500, specify the backup path of MPLS TE tunnel 2: ip 2.2.2.2 sbfd-echo remote-discriminator 500 mpls-te 2 lsp backup.

[0124] Figure 9 A session schematic diagram of a transmitting end and a reflecting end provided by the application is shown in the figure, and the session includes the following steps: Figure 9

[0125] S901, the transmitting end configures the SBFD session, and specifies the backhaul tunnel ID and the primary and backup path flags.

[0126] For example, the following configurations are performed:

[0127] mpls

[0128] mpls-te tunnel 1

[0129] #(sbfd | sbfd-echo) (primary | backup) enable reverse-tunnel TE_TUNNEL_ID lsp (primary | backup)

[0130] sbfd primary enable reverse-tunnel 2 lsp primary

[0131] ​After being configured, an SBFD session with a local descriptor of 500 and a remote descriptor of 20 is generated, assuming that the local IP address is 1.1.1.1 and the remote IP address is 2.2.2.2.

[0132] S902, the transmitting end periodically and continuously sends an MPLS echo request message to the reflecting end.

[0133] S903, after receiving the MPLS echo request message, the reflecting end generates a backhaul table item according to the MPLS echo request message and saves the backhaul table item.

[0134] S904, the reflecting end returns an MPLS echo reply message to the transmitting end.

[0135] The MPLS echo reply message is a first reply message corresponding to the MPLS echo request message.

[0136] S905, the transmitting end sends an SBFD detection message to the reflecting end.

[0137] S906, after processing the SBFD detection message, the reflecting end determines a target IP address and a remote descriptor according to the SBFD detection message, determines a corresponding SBFD backhaul tunnel ID and a primary / backup path flag in the backhaul table item according to the target IP address and the remote descriptor, and determines a target backhaul path according to the corresponding SBFD backhaul tunnel ID and the primary / backup path flag.

[0138] S907, the reflecting end returns a second reply message corresponding to the SBFD detection message to the transmitting end according to the target backhaul path.

[0139] S908, if the reflecting end does not receive the SBFD detection message corresponding to the MPLS echo request message within a preset time length, the reflecting end deletes the target IP address, the remote descriptor, the SBFD backhaul tunnel ID, and the primary / backup path flag corresponding to the MPLS echo request message.

[0140] S909, if a link fault occurs, the transmitting end generates an alarm, and the transmitting end re-sends an MPLS echo detection message to the reflecting end.

[0141] Corresponding to the above-mentioned embodiments, the application further provides a device for specifying an SBFD backhaul path in an MPLS network. Figure 10A structural schematic diagram of a device for specifying an SBFD backhaul path in an MPLS network is provided in an embodiment of the present application. The device can include at least one processor, and a memory connected in communication with the at least one processor. The memory stores instructions executable by the at least one processor to enable the at least one processor to perform a method for specifying an SBFD backhaul path in an MPLS network as described in the above embodiment.

[0142] In a possible implementation of the present application, the at least one processor is enabled to perform sending an MPLS echo request packet to the reflection end, the MPLS echo request packet including a local descriptor of the transmitting end, a local IP address of the transmitting end, an SBFD backhaul tunnel ID, and a primary / backup path flag, wherein the primary / backup path flag is used to indicate a primary LSP or a backup LSP; and after receiving a first reply packet corresponding to the MPLS echo request packet, if the first reply packet is an error-free code packet, sending an SBFD detection packet to the reflection end.

[0143] In a possible implementation of the present application, the at least one processor is enabled to perform receiving an MPLS echo request packet sent by the transmitting end, determining a local descriptor of the transmitting end in the MPLS echo request packet as a remote descriptor, determining the local descriptor of the transmitting end in the MPLS echo request packet as a target IP address, generating a backhaul table entry, the backhaul table entry being used to record the remote descriptor, the target IP address, and the SBFD backhaul tunnel ID and the primary / backup path flag in the corresponding MPLS echo request packet; returning a first reply packet corresponding to the MPLS echo request packet to the transmitting end; receiving an SBFD detection packet sent by the transmitting end, determining a local IP address in the SBFD detection packet as a target IP address of an SBFD session, and determining a local descriptor in the SBFD detection packet as a remote descriptor of the SBFD session; determining an SBFD backhaul tunnel ID and a primary / backup path flag corresponding to the SBFD session in the backhaul table entry according to the target IP address of the SBFD session and the remote descriptor of the SBFD session, and determining a target backhaul path according to the SBFD backhaul tunnel ID and the primary / backup path flag corresponding to the SBFD session; and returning a second reply packet corresponding to the SBFD detection packet to the transmitting end according to the target backhaul path.

[0144] In a possible implementation of the present application, the at least one processor is enabled to perform sending an MPLS echo request packet to the reflection end, the MPLS echo request packet including a local descriptor of the transmitting end, a local IP address of the transmitting end, an SBFD backhaul tunnel ID, and a primary / backup path flag, wherein the primary / backup path flag is used to indicate a primary LSP or a backup LSP; and after receiving a first reply packet corresponding to the MPLS echo request packet, if the first reply packet is an error-free code packet, sending an SBFD detection packet to the reflection end.

[0145] In a possible implementation of the present application, the terminal performs the following: sending, to the reflection end, an MPLS echo request message, wherein the MPLS echo request message comprises a local descriptor of the transmitting end, a local IP address of the transmitting end, an SBFD backhaul tunnel ID, and a primary-backup path flag, wherein the primary-backup path flag is used to indicate a primary LSP or a backup LSP; and after receiving a first reply message corresponding to the MPLS echo request message, sending, to the reflection end, an SBFD detection message if the first reply message is an error-free code message.

[0146] In a possible implementation of the present application, the terminal performs the following: receiving an MPLS echo request message sent by the transmitting end, determining a local descriptor of the transmitting end in the MPLS echo request message as a remote descriptor, determining the local descriptor of the transmitting end in the MPLS echo request message as a target IP address, generating a backhaul table item, wherein the backhaul table item is used to record the remote descriptor, the target IP address, and an SBFD backhaul tunnel ID and a primary-backup path flag in the corresponding MPLS echo request message; returning, to the transmitting end, a first reply message corresponding to the MPLS echo request message; receiving an SBFD detection message sent by the transmitting end, determining a local IP address in the SBFD detection message as a target IP address of an SBFD session, and determining a local descriptor in the SBFD detection message as a remote descriptor of the SBFD session; determining, in the backhaul table item, an SBFD backhaul tunnel ID and a primary-backup path flag corresponding to the SBFD session according to the target IP address of the SBFD session and the remote descriptor of the SBFD session, and determining a target backhaul path according to the SBFD backhaul tunnel ID and the primary-backup path flag corresponding to the SBFD session; and returning, to the transmitting end, a second reply message corresponding to the SBFD detection message according to the target backhaul path.

[0147] Each of the embodiments of the present application is described in a progressive manner, and the same or similar parts of each of the embodiments can be referred to each other. Each of the embodiments mainly describes the difference from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the related parts can be referred to the part of the method embodiments.

[0148] It is also to be noted that the terms "comprising", "including", and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0149] The above description is only the preferred embodiment of the application, not intended to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application shall fall within the protection scope of the application.

Claims

1. A method for specifying SBFD backhaul paths in an MPLS network, characterized in that, The method is applied to the transmitting end, and the method includes: Send an MPLS echo request message to the reflecting end. The MPLS echo request message includes the local descriptor of the transmitting end, the local IP address of the transmitting end, the SBFD backhaul tunnel ID, and the primary / backup path flag, wherein the primary / backup path flag is used to indicate the primary LSP or the backup LSP. Upon receiving the first reply message corresponding to the MPLS echo request message, if the first reply message is a message without error codes, an SBFD detection message is sent to the reflecting end.

2. The method for specifying an SBFD backhaul path in an MPLS network according to claim 1, characterized in that, Before sending an MPLS echo request message to the reflecting end, the method further includes: The local descriptor of the transmitting end is determined as the value of BFD_TLV in the MPLS echo request message, the SBFD backhaul tunnel ID is determined as the value of BFD Reverse Path Tunnel ID Sub TLVType in the MPLS echo request message, and the primary / backup path flag is determined as the value of BFD Reverse Path LSPFlag Sub TLV Type in the MPLS echo request message.

3. The method for specifying an SBFD backhaul path in an MPLS network according to claim 1, characterized in that, After sending an MPLS echo request message to the reflecting end, the method further includes: Upon receiving the first reply message corresponding to the MPLS echo request message, if the first reply message is an error code message, a configuration error message is displayed, and the MPLS echo request message is continued to be sent to the reflecting end. If no first reply message corresponding to the MPLS echo request message is received, the MPLS echo request message is sent to the reflecting end.

4. A method for specifying SBFD return paths in an MPLS network, characterized in that, The method is applied to the reflective end, and the method includes: The system receives an MPLS echo request message sent by the transmitter, determines the local descriptor of the transmitter in the MPLS echo request message as the remote descriptor, determines the local IP address of the transmitter in the MPLS echo request message as the target IP address, and generates a return entry. The return entry is used to record the remote descriptor, the target IP address, and the corresponding SBFD return tunnel ID and primary / backup path flag in the MPLS echo request message. Return the first reply message corresponding to the MPLS echo request message to the transmitting end; Receive the SBFD detection message sent by the transmitter, determine the local IP address in the SBFD detection message as the target IP address of the SBFD session, and determine the local descriptor in the SBFD detection message as the remote descriptor of the SBFD session; Based on the target IP address of the SBFD session and the remote descriptor of the SBFD session, the SBFD backhaul tunnel ID and primary / backup path flag corresponding to the SBFD session are determined in the backhaul table entry, and the target backhaul path is determined based on the SBFD backhaul tunnel ID and primary / backup path flag corresponding to the SBFD session. According to the target return path, return the second reply message corresponding to the SBFD detection message to the transmitter.

5. A method for specifying an SBFD backhaul path in an MPLS network according to claim 4, characterized in that, After generating the return trip entry, the method further includes: Start the aging timer corresponding to the MPLS echo request message. The aging timer is used to start counting from the first reply message corresponding to the MPLS echo request message returned to the transmitter. After the aging timer reaches the preset duration, delete the remote descriptor, target IP address, SBFD backhaul tunnel ID and primary / backup path flag corresponding to the MPLS echo request message from the backhaul table entry.

6. A method for specifying an SBFD backhaul path in an MPLS network according to claim 4, characterized in that, After returning the second reply message corresponding to the SBFD detection message to the transmitter, the method further includes: Adjust the aging timer corresponding to the SBFD session to restart the timing from the second reply message corresponding to the SBFD detection message returned to the transmitter.

7. A method for specifying an SBFD backhaul path in an MPLS network according to claim 4, characterized in that, After determining the local IP address in the SBFD detection packet as the target IP address of the SBFD session, and determining the local descriptor in the SBFD detection packet as the remote descriptor of the SBFD session, the method further includes: If the SBFD backhaul tunnel ID and primary / backup path flag corresponding to the SBFD session do not exist in the backhaul table entry, then the second reply message corresponding to the SBFD detection message is returned to the transmitter according to the dynamic IP routing path from the reflector to the transmitter.

8. A method for specifying an SBFD backhaul path in an MPLS network according to claim 4, characterized in that, After receiving the SBFD detection message sent by the transmitter, the method further includes: According to the preset static IP routing path from the reflector to the transmitter, the second reply message corresponding to the SBFD detection message is returned to the transmitter.

9. A device for specifying SBFD backhaul paths in an MPLS network, characterized in that, The device includes: At least one processor; and, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor to enable the at least one processor to perform a method for specifying an SBFD backhaul path in an MPLS network according to any one of claims 1-8.

10. A non-volatile computer storage medium, characterized in that, The storage medium is a non-volatile computer-readable storage medium that stores at least one program, each program including instructions that, when executed by a terminal, cause the terminal to perform a method for specifying an SBFD backhaul path in an MPLS network according to any one of claims 1-8.

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