A seamless bidirectional forwarding detection method and device, a forwarding node and a medium

Abstract

This application provides a seamless bidirectional forwarding detection method, apparatus, forwarding node, and medium, relating to the field of communication technology. The method includes: when the path to be detected is a ring path, the forwarding node initiating SBFD generates a first SBFD message, the first SBFD message including a first remote identifier field, which carries the session local identifier on the forwarding node; and sending the first SBFD message along the ring path. This solution can solve the problems of detection failure and high pressure on forwarding nodes when performing SBFD on a ring path.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a seamless bidirectional forwarding detection method, apparatus, forwarding node, and medium. Background Technology

[0002] In application scenarios such as Segment Routing over IPv6 (SRv6) Service Function Chain (SFC) based on Internet Protocol Version 6 (IPv6), the configured SRv6 policy path is often a ring path. When performing Seamless Bidirectional Forwarding Detection (SBFD) on the ring path, the forwarding node performing the SBFD probe is both the head node and the tail node of the SBFD probe path (i.e., the ring path).

[0003] In this situation, the following two problems will exist: 1) The forwarding node does not support the same SBFD probe for the head node and the tail node, resulting in probe failure; 2) The forwarding node supports the same SBFD probe for the head node and the tail node, which requires the forwarding node to perform the operation of sending and receiving SBFD messages for the head node and the operation of reflecting SBFD messages for the tail node at the same time, which leads to a large pressure on the forwarding node. Summary of the Invention

[0004] The purpose of this application is to provide a seamless bidirectional forwarding detection method, apparatus, forwarding node, and medium to solve the problems of detection failure and high pressure on forwarding nodes when performing SBFD on a ring path. The specific technical solution is as follows:

[0005] In a first aspect, embodiments of this application provide a seamless bidirectional forwarding detection method, applied to a forwarding node initiating SBFD, the method comprising:

[0006] When the path to be detected is a ring path, a first SBFD message is generated. The first SBFD message includes a first remote identifier field, which carries the session local identifier on the forwarding node.

[0007] The first SBFD message is sent along the ring path.

[0008] In some embodiments, the first SBFD message is an SBFD session negotiation message; the SBFD session negotiation message further includes a first local identifier field, the first local identifier field carries the session reflection end identifier on the forwarding node, and the session state in the SBFD session negotiation message is set to the up state.

[0009] In some embodiments, the first SBFD message is an SBFD probe message; the forwarding node configures the remote identifier contained in the SBFD probe message to be the session local identifier on the forwarding node, and the session state in the SBFD probe message is set to UP state.

[0010] In some embodiments, the forwarding node configures the local identifier included in the SBFD probe message to be the session reflection endpoint identifier on the forwarding node;

[0011] The SBFD probe message also includes a second local identifier field, which carries the session reflection identifier on the forwarding node.

[0012] In some embodiments, the step of generating a first SBFD message when the path to be detected is a loop path includes:

[0013] Detect whether the path to be probed is configured with a ring parameter; if the ring parameter is configured, generate a first SBFD message; or,

[0014] Detect whether the tail node of the path to be probed is the forwarding node; if it is the forwarding node, generate the first SBFD message.

[0015] In some embodiments, the method further includes:

[0016] When the path to be detected is a non-circular path, a second SBFD message is generated. The second SBFD message includes a second remote identifier field, which carries the session reflection end identifier on the forwarding node.

[0017] The second SBFD message is sent along the non-circular path.

[0018] Secondly, embodiments of this application provide a seamless bidirectional forwarding detection device, applied to a forwarding node initiating SBFD, the device comprising:

[0019] The message generation module is used to generate a first SBFD message when the path to be detected is a ring path. The first SBFD message includes a first remote identifier field, which carries the session local identifier on the forwarding node.

[0020] The message sending module is used to send the first SBFD message along the ring path.

[0021] In some embodiments, the first SBFD message is an SBFD session negotiation message; the message generation module includes a session negotiation submodule; the session reflection end identifier in the session negotiation submodule is the session reflection end identifier on the forwarding node, and the session local end identifier in the session negotiation submodule is the session local end identifier on the forwarding node.

[0022] The session negotiation submodule is used to generate the SBFD session negotiation message based on the session reflection end identifier and the session local end identifier in the session negotiation submodule when the path to be detected is a ring path. The SBFD session negotiation message also includes a first local end identifier field, which carries the session reflection end identifier in the session negotiation submodule. The first remote end identifier field carries the session local end identifier in the session negotiation submodule. The session state in the SBFD session negotiation message is set to UP state.

[0023] In some embodiments, the first SBFD message is an SBFD probe message; the message generation module includes a session delivery submodule and a session maintenance submodule;

[0024] The session delivery submodule is used to configure the session local identifier on the forwarding node as the session reflection identifier to the session maintenance submodule.

[0025] The session maintenance submodule is used to generate the SBFD probe message based on the session reflection endpoint identifier in the session maintenance submodule. The first remote identifier field carries the session reflection endpoint identifier in the session maintenance submodule, and the session state in the SBFD probe message is set to UP state.

[0026] In some embodiments, the session delivery submodule is further configured to configure the session reflection endpoint identifier on the forwarding node as the session local endpoint identifier to the session maintenance submodule;

[0027] The session maintenance submodule is specifically used to generate the SBFD probe message based on the session reflection end identifier and the session local end identifier in the session maintenance submodule. The SBFD probe message also includes a second local end identifier field, which carries the session local end identifier in the session maintenance submodule.

[0028] In some embodiments, the message generation module includes a session negotiation submodule;

[0029] The session negotiation submodule is specifically used for: detecting whether the path to be probed is configured with a ring parameter; if the ring parameter is configured, generating a first SBFD message; or, detecting whether the tail node of the path to be probed is the forwarding node; if it is the forwarding node, generating a first SBFD message.

[0030] In some embodiments, the message generation module is further configured to generate a second SBFD message when the path to be detected is a non-ring path, the second SBFD message including a second remote identifier field, the second remote identifier field carrying a session reflection end identifier on the forwarding node;

[0031] The message sending module is also used to send the second SBFD message along the non-circular path.

[0032] Thirdly, embodiments of this application provide a forwarding node, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0033] Memory, used to store computer programs;

[0034] The processor, when executing a program stored in memory, implements any of the methods provided in the first aspect.

[0035] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements any of the methods provided in the first aspect.

[0036] This application also provides a computer program product containing instructions that, when run on a computer, cause the computer to perform any of the methods provided in the first aspect.

[0037] Beneficial effects of the embodiments in this application:

[0038] In the technical solution provided in this application embodiment, when the forwarding node initiating SBFD is located on a ring path and needs to probe the ring path, the value carried by the remote identifier field in the SBFD message generated by the forwarding node is the session local identifier on the forwarding node. When the SBFD message is forwarded along the ring path and returns to the forwarding node, the forwarding node sees that the value carried by the remote identifier field in the SBFD message is the session local identifier on the forwarding node, and then records that it has received the SBFD message corresponding to the session local identifier, ending this SBFD, thus realizing SBFD on the ring path.

[0039] In this embodiment, when performing SBFD, the forwarding node constructs an SBFD message according to the format of the reflecting end (i.e., the tail node), simulates the sending of the SBFD message by the reflecting end, and then performs reception processing on the SBFD message. That is, the forwarding node only needs to perform the operations of sending and receiving SBFD messages, without performing the operation of reflecting SBFD messages. When SBFD is implemented on a ring path, the operations performed by the forwarding node are reduced, thus reducing the pressure on the forwarding node.

[0040] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0042] Figure 1 This is a schematic diagram of an existing SBFD process;

[0043] Figure 2 This is a deployment diagram of SRv6 SFC;

[0044] Figure 3 A flowchart illustrating the seamless bidirectional forwarding detection method provided in this application embodiment;

[0045] Figure 4 This is a schematic diagram of a first structure of the seamless bidirectional forwarding detection device provided in the embodiments of this application;

[0046] Figure 5 This is a second structural schematic diagram of the seamless bidirectional forwarding detection device provided in the embodiments of this application;

[0047] Figure 6 This is a schematic diagram of a third structure of the seamless bidirectional forwarding detection device provided in the embodiments of this application;

[0048] Figure 7 A schematic diagram of the SBFD session negotiation process provided in an embodiment of this application;

[0049] Figure 8 A schematic diagram of the SBFD detection process provided in the embodiments of this application;

[0050] Figure 9 This is a schematic diagram of a forwarding node provided in an embodiment of this application. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0052] SBFD: A protocol for quickly detecting network faults. Compared to traditional Bidirectional Forwarding Detection (BFD), SBFD simplifies the state machine, supporting only two states: UP and DOWN, thus shortening session negotiation time and making it suitable for large-scale detection scenarios. SBFD introduces a reflector mechanism, requiring session maintenance only at one end, making it suitable for situations where only one end needs link state detection. These two characteristics make SBFD suitable for connectivity state detection of SRv6 Policy segment lists (SID lists), and it has become the primary method for segment list detection.

[0053] like Figure 1 The SBFD process shown depicts an SRv6 Policy path of forwarding node R1 → forwarding node R2 → forwarding node R3. Forwarding node R1 is the head node of the SRv6 Policy path, i.e., the initiator of SBFD, and forwarding node R3 is the tail node of the SRv6 Policy path, i.e., the reflector of SBFD. When an SBFD session is established between forwarding node R1 and forwarding node R3, the SBFD detection process for the SRv6 Policy path is as follows:

[0054] (1) Forwarding node R1 sends SBFD probe message 1. The format of SBFD probe message 1 is as follows: the source address (SA) of the outer IPv6 header is the local address (Local Address) 1::1 of forwarding node R1, the destination address (DA) is the segment identifier (SID) of forwarding node R2, and the Segment Routing Header (SRH) encapsulates a list of SIDs (i.e., the SIDs of forwarding node R2 and forwarding node R3, and the local address of forwarding node R3 3::1); the local identifier (My Discriminator (MD) included in the inner SBFD message is the local discriminator (Local Discriminator) 100 on forwarding node R1, the remote identifier (Your Discriminator (YD) included in the inner SBFD message is the remote discriminator (Remote Discriminator) 300 on forwarding node R1, and the session state included in the inner SBFD message is the up state. The session reflection endpoint identifier on forwarding node R1 is the same as the session local endpoint identifier on forwarding node R3.

[0055] (2) Based on the SRH included in SBFD probe packet 1, forwarding node R2 updates the DA of the outer IPv6 header in SBFD probe packet 1 to the SID of forwarding node R3, obtains SBFD probe packet 2, and sends SBFD probe packet 2 to forwarding node R3.

[0056] (3) After SBFD probe packet 2 arrives at forwarding node R3, it is processed by SRv6. The DA in the outer IPv6 header of SBFD probe packet 2 is updated to 3::1, resulting in SBFD probe packet 3. Forwarding node R3 finds that the DA in the outer IPv6 header of SBFD probe packet 3 is 3::1, which is the local address of forwarding node R3. Then, based on the User Datagram Protocol (UDP) port number, it identifies that YD in the inner SBFD packet is the session local identifier 300 on forwarding node R3. SBFD reflection processing is performed, that is, the source address and destination address in the outer IPv6 header of SBFD probe packet 3 are swapped, and the MD and YD included in the inner SBFD packet are swapped, resulting in SBFD probe packet 4. SBFD probe packet 4 is sent to forwarding node R1.

[0057] (4) When forwarding node R1 receives SBFD probe message 4, it identifies YD in the inner SBFD message as session local identifier 100 on forwarding node R1. Based on this session local identifier 100, it finds the SBFD session, records the received packet, that is, records the SBFD message corresponding to the session local identifier 100, resets the timeout duration of the SBFD session, and prevents the SBFD session from closing (DOWN) due to timeout.

[0058] To meet users' security and stability requirements, data packets often need to pass through various service functions (SFs) sequentially according to business logic when transmitted in the network, such as firewalls, intrusion prevention systems (IPS), application accelerators, and network address translation (NAT) devices. SRv6 SFC is a technology that guides packets through application layer service nodes sequentially along a specified path by adding SRv6 path information to the original packets, which can conveniently meet the above-mentioned user requirements.

[0059] In the application scenario of computing network security resource pool, the deployment of SRv6 SFC is as follows: Figure 2 As shown, forwarding nodes R1 to R3 are network nodes, the gateway (GW) is the security resource pool gateway, and forwarding nodes SF1 to SF3 are application layer SFs within the security resource pool, providing services such as firewall, IPS, and NAT.

[0060] To facilitate security service orchestration, service paths within the security resource pool are independently orchestrated as SRv6 Policy paths (i.e., SFC paths) and provided to external networks through binding to SIDs (BSIDs). For example... Figure 2 As shown, the service path orchestrated on the GW is: GW→SF1→SF2→SF3→GW, and a BSID (such as GW BSID) is assigned to the GW. The path orchestrated on the external network forwarding node R1 is: R1→R2→GW (using GW BSID)→R3. Therefore, the forwarding path of the data packets is as follows: Figure 2 As shown by the dashed line, after the data packet is forwarded from forwarding node R1 to forwarding node R2, it is sent to GW. Then, based on the SFC path associated with GW BSID, it passes through forwarding nodes SF1 to SF3 in sequence within the security resource pool before returning to GW, and then is forwarded to forwarding node R3.

[0061] To ensure link reliability, the Gateway (GW) needs to probe the validity of the SRv6 Policy paths orchestrated on the GW, such as using SBFD to probe the connectivity of the SRv6 Policy Segment List. However, within the security resource pool, the head and tail nodes of the SRv6 Policy paths are the same, such as... Figure 2 As shown, the head and tail nodes of the SRv6 Policy path are both GWs. In this case, if the existing SBFD is used to probe the SRv6 Policy path, the following problem exists:

[0062] 1) When the SBFD message arrives at the tail node GW of the SRv6 Policy path, after being reflected by the tail node GW, the DA in the outer IPv6 header of the SBFD message is the local address of the tail node GW. The reflecting end (i.e. the tail node GW) cannot handle this situation, resulting in the failure of SBFD detection.

[0063] 2) When an SBFD packet arrives at the tail node GW of the SRv6 Policy path, it undergoes reflection processing. The outer IPv6 header of the SBFD packet contains the local address. The reflecting end (i.e., the tail node GW) can then re-execute the SBFD reception process to find the associated SBFD session and record the received packet. However, at this point, the GW is performing both reflection and packet reception operations simultaneously, doubling the load on the GW compared to the probing device (i.e., the head node) on a non-ring path.

[0064] To address the aforementioned issues, this application provides a seamless bidirectional forwarding detection method, applied to the forwarding node initiating SBFD, such as... Figure 3 As shown, the method includes the following steps:

[0065] Step S301: When the path to be detected is a ring path, a first SBFD message is generated. The first SBFD message includes a remote identifier field, which carries the session local identifier on the forwarding node.

[0066] Step S302: Send the first SBFD message along the loop path.

[0067] In the technical solution provided in this application embodiment, when the forwarding node initiating SBFD is located on a ring path and needs to probe the ring path, the value carried by the remote identifier field in the SBFD message generated by the forwarding node is the session local identifier on the forwarding node. When the SBFD message is forwarded along the ring path and returns to the forwarding node, the forwarding node sees that the value carried by the remote identifier field in the SBFD message is the session local identifier on the forwarding node, and then records that it has received the SBFD message corresponding to the session local identifier, ending this SBFD, thus realizing SBFD on the ring path.

[0068] In this embodiment, when the forwarding node performs SBFD, it constructs an SBFD message according to the format of the reflecting end (i.e., the tail node), simulates the sending of the SBFD message by the reflecting end, and then performs reception processing on the SBFD message. That is, the forwarding node only needs to perform the operations of sending and receiving SBFD messages, without having to perform the operation of reflecting SBFD messages. When SBFD is implemented on a ring path, the number of operations performed by the forwarding node is reduced, thus reducing the pressure on the forwarding node.

[0069] In this embodiment, the forwarding node is the initiator of SBFD, and can be the head node of a ring path, such as... Figure 2 In this context, GW can also be the head node of a non-circular path, such as... Figure 1 The forwarding node R1 in the diagram. For ease of description, the forwarding node that initiates SBFD will be described as the initiating end below.

[0070] In step S301 above, the path to be detected is the SRv6 Policy path that requires SBFD.

[0071] For the path to be probed, the initiating end determines whether the path is a ring path. If it is determined to be a ring path, the initiating end generates an SBFD message, i.e., the first SBFD message. The format of the first SBFD message is as follows: the remote identifier (YD) field carries the session local identifier on the initiating end. Other contents included in the first SBFD message are as described in the prior art. For example, the format of the first SBFD message can be: the SA in the outer IPv6 header is the local address of the initiating end, the DA is the SID of the next-hop node on the ring path, and the SRH encapsulates a list of SIDs (i.e., the SIDs of each node on the ring path and the local address of the tail node); the MD included in the inner SBFD message is not limited and can be the session local identifier on the initiating end, the session reflection identifier, or other values.

[0072] After receiving the first SBFD message, the initiating end executes step S302, sending the first SBFD message along the ring path. Each node on the ring path forwards the first SBFD message according to the SRH in the first SBFD message, and thus the first SBFD message reaches the initiating end.

[0073] When the first SBFD message is received, the initiating end can record the SBFD message corresponding to the remote identifier in the first SBFD message, reset the timeout duration of the SBFD session corresponding to the session local identifier on the initiating end, prevent the SBFD session from timeout and down, and complete one SBFD.

[0074] If the first SBFD message is not received when the SBFD session times out, the initiator can set the state of the SBFD session to DOWN.

[0075] In this embodiment of the application, when the initiating end performs SBFD of the ring path, it performs the sending and receiving operations of SBFD messages. No additional reflection processing is added due to the SBFD of the ring path, thus ensuring the efficiency of SBFD.

[0076] In some embodiments, the initiator may determine whether the path to be probed is a loop path using any of the following methods.

[0077] Method 1: Detect whether the path to be probed is configured with a ring parameter; if a ring parameter is configured, generate the first SBFD message.

[0078] In Method 1, the user can manually configure ring parameters, i.e., add ring parameters to the ring path. These ring parameters can be 0 or 1, or other symbols. The ring parameter indicates that the probed path is a ring path. The initiating end checks whether the path to be probed has ring parameters configured. If the path to be probed has ring parameters configured, it indicates that the path to be probed is a ring path, and the initiating end generates the first SBFD message, then executes step S302.

[0079] If the path to be probed is not configured with a ring parameter, it indicates that the path to be probed is a non-ring path. The initiating end can use existing technology to generate a second SBFD message. The second SBFD message includes a second remote identifier field, which carries the session reflection endpoint identifier on the initiating end. Other contents included in the second SBFD message are as described in existing technology. For example, the format of the second SBFD message is as follows: the SA in the outer IPv6 header is the local address of the initiating end, the DA is the SID of the next-hop node on the non-ring path, and the SRH encapsulates a list of SIDs (i.e., the SIDs of each node on the non-ring path and the local address of the tail node); the MD included in the inner SBFD message is the session local endpoint identifier on the initiating end, and the YD included in the inner SBFD message is the session reflection endpoint identifier on the initiating end.

[0080] Method 2: Detect whether the tail node of the path to be probed is the initiator; if it is the initiator, generate the first SBFD message.

[0081] In Method 2, the initiating end automatically detects whether the path to be probed is a circular path. That is, the initiating end detects whether the tail node of the path to be probed is the initiating end itself. If the tail node is the initiating end itself, it means that the path to be probed is a circular path, and the initiating end can generate the first SBFD message and then execute step S302.

[0082] If the tail node is not the initiator itself, it indicates that the path to be probed is a non-ring path. The initiator can use existing technology to generate a second SBFD message. The second SBFD message includes a second remote identifier field, which carries the session reflector identifier on the initiator. Other contents included in the second SBFD message are as described in existing technology. For example, the format of the second SBFD message is as follows: the SA in the outer IPv6 header is the local address of the initiator, the DA is the SID of the next-hop node on the non-ring path, and the SRH encapsulates a list of SIDs (i.e., the SIDs of each node on the non-ring path and the local address of the tail node); the MD included in the inner SBFD message is the session local identifier on the initiator, and the YD included in the inner SBFD message is the session reflector identifier on the initiator.

[0083] In some embodiments, the first SBFD message can be an SBFD session negotiation message or an SBFD probe message.

[0084] When the first SBFD message is an SBFD session negotiation message, the SBFD session negotiation message may also include a local identifier field (i.e., the first local identifier field), which carries the session reflection identifier on the initiating end, and the session state in the SBFD session negotiation message is set to UP state.

[0085] Thus, when the initiating end receives the SBFD session negotiation message it sent, it can see that the value of the first remote identifier field in the SBFD session negotiation message is the session local identifier on the initiating end, the value of the first local identifier field is the session reflection identifier on the initiating end, and the session status is set to UP. This indicates that the session negotiation was successful and the SBFD session was established.

[0086] When the first SBFD message is an SBFD probe message, the initiating end configures the remote identifier contained in the SBFD probe message to be the session local identifier on the initiating end, and the session state in the SBFD probe message is set to UP state.

[0087] In this embodiment, the local identifier in the SBFD probe message configured by the initiating end can be the session reflector identifier on the initiating end, or any other arbitrary value. Because, on the ring path, the initiating end only focuses on the remote identifier (YD) field when receiving the reflected SBFD message, configuring the local identifier (MD) in the SBFD probe message to be the session reflector identifier or any other arbitrary value does not affect the SBFD probe process.

[0088] When the initiating end configures the local identifier in the SBFD probe message to be the session reflector identifier on the initiating end, the SBFD probe message may also include a local identifier field (i.e., a second local identifier field), which carries the session reflector identifier on the initiating end.

[0089] In this embodiment, the example is taken where the initiating end configures the local identifier in the SBFD probe message to be the session reflection endpoint identifier on the initiating end. When the first SBFD message is an SBFD probe message, the initiating end directly configures the remote identifier in the SBFD probe message to be the session local endpoint identifier on the initiating end. In this way, for the module that generates the SBFD probe message, it generates and sends the SBFD probe message according to the existing header node method, but actually generates and sends the SBFD probe message according to the tail node (i.e., reflection endpoint) format. This makes SBFD probe transparent to the module that generates the SBFD probe message, avoids modifications to the implementation of the module that generates the SBFD probe message in the scenario of maintaining the session, and reduces the implementation complexity.

[0090] Corresponding to the aforementioned seamless bidirectional forwarding detection method, this application also provides a seamless bidirectional forwarding detection device, such as... Figure 4 As shown, this device, applied to the forwarding node that initiates SBFD, includes a message generation module 410 and a message sending module 420:

[0091] The message generation module 410 is used to generate a first SBFD message when the path to be detected is a ring path. The first SBFD message includes a first remote identifier field, which carries the session local identifier on the forwarding node.

[0092] The message sending module 420 is used to send the first SBFD message along the ring path.

[0093] In the technical solution provided in this application embodiment, when the forwarding node initiating SBFD is located on a ring path and needs to probe the ring path, the value carried by the remote identifier field in the SBFD message generated by the forwarding node is the session local identifier on the forwarding node. When the SBFD message is forwarded along the ring path and returns to the forwarding node, the forwarding node sees that the value carried by the remote identifier field in the SBFD message is the session local identifier on the forwarding node, and then records that it has received the SBFD message corresponding to the session local identifier, ending this SBFD, thus realizing SBFD on the ring path.

[0094] In this embodiment, when performing SBFD, the forwarding node constructs an SBFD message according to the format of the reflecting end (i.e., the tail node), simulates the sending of the SBFD message by the reflecting end, and then performs reception processing on the SBFD message. That is, the forwarding node only needs to perform the operations of sending and receiving SBFD messages, without performing the operation of reflecting SBFD messages. When SBFD is implemented on a ring path, the operations performed by the forwarding node are reduced, thus reducing the pressure on the forwarding node.

[0095] For ease of description, the forwarding node that initiates SBFD will be described as the initiator below.

[0096] In some embodiments, the first SBFD message is an SBFD session negotiation message; such as Figure 5 As shown, the message generation module 410 may include a session negotiation submodule 411; the session reflection end identifier in the session negotiation submodule 411 is the session reflection end identifier on the initiating end, and the session local end identifier in the session negotiation submodule 411 is the session local end identifier on the initiating end.

[0097] The session negotiation submodule 411 is used to generate an SBFD session negotiation message based on the session reflection end identifier and the session local end identifier in the session negotiation submodule when the path to be probed is a ring path. The SBFD session negotiation message also includes a first local end identifier field, which carries the session reflection end identifier in the session negotiation submodule. The first remote end identifier field carries the session local end identifier in the session negotiation submodule. The session state in the SBFD session negotiation message is set to UP state.

[0098] In this embodiment, the session negotiation submodule 411 is implemented by the control plane software. When the SBFD session negotiation path is a ring path, the control plane session negotiation submodule 411 performs SBFD session negotiation for the ring path, that is, it sends messages according to the message format of the reflecting end. Specifically, MD in the SBFD session negotiation message is the session reflecting end identifier on the session negotiation submodule 411, YD is the session local end identifier on the session negotiation submodule 411, and the session state is UP (in the prior art, the state in the SBFD session negotiation message sent by the initiating end during SBFD session negotiation is DOWN, and the reflecting end modifies the state to UP). When the SBFD session negotiation message returns to the initiating end along the SRv6 Policy path, the initiating end executes the existing SBFD session negotiation message receiving process, obtains a message state of UP, and the session negotiation is successful.

[0099] In some embodiments, the first SBFD message is an SBFD probe message; such as Figure 6As shown, the message generation module 410 may include a session distribution submodule 412 and a session maintenance submodule 413;

[0100] The session delivery submodule 412 is used to configure the session local identifier on the initiating end as the session reflection end identifier to the session maintenance submodule 413.

[0101] The session maintenance submodule 413 is used to generate an SBFD probe message based on the session reflection end identifier in the session maintenance submodule. The first remote identifier field carries the session reflection end identifier in the session maintenance submodule, and the session state in the SBFD probe message is set to UP state.

[0102] In this embodiment, after successful SBFD session negotiation, the session distribution submodule 412 can distribute session parameters to the session maintenance submodule 413. The session distribution submodule 412 can be implemented in control plane software, and the session maintenance submodule 413 can be implemented in control plane software or in hardware such as a network processor (NP) or a field-programmable gate array (FPGA). Session parameters may include, but are not limited to, parameters such as the session local identifier, the session reflector identifier, the transmission time interval, the reception time interval, the detection time multiplier, and the list of detected SIDs.

[0103] For SBFD on a ring path, when the session sending submodule 412 sends session parameters, it can swap the positions of the session local identifier and the session reflection identifier in the control plane software. The session local identifier on the initiating end is used as the session reflection identifier (i.e., the remote identifier contained in the SBFD probe message) and configured for the session maintenance submodule 413; the session reflection identifier on the initiating end is used as the session local identifier (i.e., the local identifier contained in the SBFD probe message) and configured for the session maintenance submodule 413.

[0104] In this embodiment, the session local identifier configured by the session sending submodule 412 to the session maintenance submodule 413 can also be any value other than the session reflection identifier on the initiating end, which improves the flexibility of the implementation.

[0105] The session maintenance submodule 413 can generate SBFD probe messages based on session parameters such as the session reflector identifier in the session maintenance submodule 413, following the existing header node method, and send them through the message sending module 420. In reality, the SBFD probe messages are generated according to the reflector format and sent through the message sending module 420; that is, the remote identifier included in the SBFD probe message is actually the session local identifier. This makes SBFD probing transparent to the session maintenance submodule 413, avoiding modifications to the implementation of the session maintenance submodule 413 in scenarios involving session maintenance, and reducing implementation complexity.

[0106] In this embodiment of the application, the session maintenance submodule 413 can periodically construct and send SBFD probe messages, or it can pre-construct and save SBFD probe messages, and then periodically read and send SBFD probe messages.

[0107] In addition, in this embodiment of the application, the seamless bidirectional forwarding detection device may also include a message receiving module. The session sending submodule 412 can send session parameters to the session maintenance submodule 413. In these session parameters, the positions of the session local identifier and the session reflection identifier are not swapped. That is, the session local identifier on the initiating end is used as the session local identifier and configured for the message receiving module; the session reflection identifier on the initiating end is used as the session reflection identifier and configured for the message receiving module.

[0108] After the session maintenance submodule 413 sends an SBFD probe message, the message receiving module starts a receive timer to check whether the SBFD session corresponding to the session local identifier on the message receiving module has timed out. The duration of the receive timer can be a multiple of the receive time interval and the detection time. For example, if the corresponding SBFD probe message is not received when the receive timer expires, the corresponding SBFD probe message is the SBFD probe message with the remote identifier being the session local identifier on the message receiving module. In this case, the message receiving module can determine that the SBFD session corresponding to the session local identifier has timed out and set the status of the SBFD session to DOWN. If the corresponding SBFD probe message is received before the receive timer expires, the message receiving module can determine that the SBFD session corresponding to the session local identifier has not timed out and resets the receive timer.

[0109] In some embodiments, the message generation module 410 may include a session negotiation submodule 411; the session negotiation submodule 411 may be specifically used to: detect whether the path to be probed is configured with a ring parameter; if a ring parameter is configured, generate a first SBFD message; or, detect whether the tail node of the path to be probed is the initiator; if it is the initiator, generate a first SBFD message.

[0110] In some embodiments, the message generation module 410 (such as the session negotiation submodule 411 or session maintenance submodule 413 described above) can also be used to generate a second SBFD message when the path to be probed is a non-circular path. The second SBFD message includes a second remote identifier field, which carries the session reflection end identifier on the initiating end.

[0111] The message sending module 420 can also be used to send a second SBFD message along a non-circular path.

[0112] The following is combined Figure 7 The SBFD session negotiation process shown is as follows: Figure 8 The SBFD detection process shown illustrates the seamless bidirectional forwarding detection method provided in the embodiments of this application. Figure 7 and Figure 8 In the example, forwarding node R1 is configured with two SRv6Policy paths: a ring path 1 {forwarding node R1 → forwarding node R2 → forwarding node R3 → forwarding node R1} and a non-ring path 2 {forwarding node R1 → forwarding node R4 → forwarding node R5}. Ring path 1 is configured with ring parameters, while non-ring path 2 is not. Forwarding node R1 is the forwarding node that initiated SBFD, i.e., the initiator.

[0113] In the session negotiation submodule of forwarding node R1, the local address is configured as 1::1; the session local identifier (LD) corresponding to ring path 1 is 100, and the session reflective identifier (RD) corresponding to ring path 1 is 10; the session local identifier corresponding to non-ring path 2 is 200, and the session reflective identifier corresponding to non-ring path 2 is 20. In the session negotiation submodule of forwarding node R5, the local address is configured as 5::5, and the session local identifier corresponding to non-ring path 2 is 20.

[0114] like Figure 7 As shown, during the SBFD session negotiation phase:

[0115] 1) For ring path 1, the session negotiation submodule of forwarding node R1 generates SBFD session negotiation message 1 and sends it. The format of SBFD session negotiation message 1 is as follows: the SA in the outer IPv6 header is the local address 1::1 of forwarding node R1, the DA is the SID of forwarding node R2, and the SRH encapsulates SID list 1 (i.e., the SIDs of forwarding node R2, forwarding node R3, and forwarding node R1, and the local address 1::1 of forwarding node R1); the MD in the inner SBFD message is 10, the YD in the inner SBFD message is 100, and the session state in the inner SBFD message is UP.

[0116] Based on the SRH included in SBFD session negotiation message 1, forwarding node R2 updates the DA in the outer IPv6 header of SBFD session negotiation message 1 to the SID of forwarding node R3, obtains SBFD session negotiation message 2, and sends it.

[0117] Based on the SRH included in SBFD session negotiation message 2, forwarding node R3 updates the DA in the outer IPv6 header of SBFD session negotiation message 2 to the SID of forwarding node R1, obtains SBFD session negotiation message 3, and sends it.

[0118] The message receiving module of forwarding node R1 updates the DA of the outer IPv6 header in SBFD session negotiation message 3 to 1::1 based on the SRH included in SBFD session negotiation message 3, thus obtaining SBFD session negotiation message 4. The message receiving module of forwarding node R1 finds that the DA of the outer IPv6 header in SBFD session negotiation message 4 is 1::1, which is the local address of forwarding node R1. Furthermore, based on the UDP port number, it identifies that YD in the inner SBFD message is the session local identifier 100 of forwarding node R1, and the session state is UP, indicating that the session negotiation was successful.

[0119] 2) For non-ring path 2, the session negotiation submodule of forwarding node R1 generates and sends SBFD session negotiation message 5. The format of this SBFD session negotiation message 5 is as follows: the SA in the outer IPv6 header is the local address 1::1 of forwarding node R1, the DA is the SID of forwarding node R4, and the SRH encapsulates SID list 2 (i.e., the SIDs of forwarding node R4 and forwarding node R5, and the local address 5::5 of forwarding node R5); the MD in the inner SBFD message is 200, the YD in the inner SBFD message is 20, and the session state in the inner SBFD message is DOWN.

[0120] Based on the SRH included in SBFD session negotiation message 5, forwarding node R4 updates the DA in the outer IPv6 header of SBFD session negotiation message 5 to the SID of forwarding node R5, thus obtaining SBFD session negotiation message 6, and sends it.

[0121] Based on the SRH included in SBFD session negotiation message 6, forwarding node R5 updates the DA of the outer IPv6 header in SBFD session negotiation message 6 to 5::5, resulting in SBFD session negotiation message 7. Forwarding node R5 discovers that the DA of the outer IPv6 header in SBFD session negotiation message 7 is 5::5, which is the local address of forwarding node R5. Then, based on the UDP port number, it identifies that YD in the inner SBFD message is the session local identifier 20 of forwarding node R5. It performs SBFD reflection processing, that is, it swaps the source address and destination address in the outer IPv6 header of SBFD session negotiation message 7, swaps the MD and YD included in the inner SBFD message, and sets the session state to UP, resulting in SBFD session negotiation message 8, which is then sent to forwarding node R1.

[0122] The message receiving module of forwarding node R1 receives SBFD session negotiation message 8, identifies the inner SBFD message, YD is the session local identifier 200 of forwarding node R1, and the session status is UP, indicating that the session negotiation is successful.

[0123] After successful session negotiation, the session distribution submodule of forwarding node R1 distributes session parameter 1 (corresponding to ring path 1) and session parameter 2 (corresponding to non-ring path 2) to the session maintenance submodule, and distributes session parameter 3 (corresponding to ring path 1) and session parameter 4 (corresponding to non-ring path 2) to the message receiving module. Specifically, in session parameter 1, the local session identifier is 10 and the reflecting session identifier is 100; in session parameter 3, the local session identifier is 100 and the reflecting session identifier is 10; and in session parameters 2 and 4, the local session identifier is 200 and the reflecting session identifier is 20.

[0124] like Figure 8 As shown, during the SBFD detection phase:

[0125] 1) For ring path 1, the session maintenance submodule of forwarding node R1 generates SBFD probe packet 1 and sends it. The format of SBFD probe packet 1 is as follows: the SA in the outer IPv6 header is the local address 1::1 of forwarding node R1, the DA is the SID of forwarding node R2, and the SRH encapsulates the SID list 1; the MD in the inner SBFD packet is 10, the YD in the inner SBFD packet is 100, and the session state in the inner SBFD packet is UP.

[0126] Based on the SRH included in SBFD probe packet 1, forwarding node R2 updates the DA in the outer IPv6 header of SBFD probe packet 1 to the SID of forwarding node R3, thus obtaining SBFD probe packet 2, and sends it.

[0127] Based on the SRH included in SBFD probe packet 2, forwarding node R3 updates the DA in the outer IPv6 header of SBFD probe packet 2 to the SID of forwarding node R1, thus obtaining SBFD probe packet 3, and sends it.

[0128] The packet receiving module of forwarding node R1 updates the DA of the outer IPv6 header in SBFD probe packet 3 to 1::1 based on the SRH included in SBFD probe packet 3, thus obtaining SBFD probe packet 4. The packet receiving module of forwarding node R1 discovers that the DA of the outer IPv6 header in SBFD probe packet 4 is 1::1, which is the local address of forwarding node R1. It then identifies the inner SBFD packet based on the UDP port number, where YD is the session local identifier 100 of forwarding node R1, and the session state is UP. It resets the timeout duration of the SBFD session corresponding to session local identifier 100 to prevent the SBFD session from timeout and going down.

[0129] 2) For non-ring path 2, the session maintenance submodule of forwarding node R1 generates SBFD probe packet 5 and sends it. The format of SBFD probe packet 5 is as follows: the SA in the outer IPv6 header is the local address 1::1 of forwarding node R1, the DA is the SID of forwarding node R4, and the SRH encapsulates the SID list 2; the MD in the inner SBFD packet is 200, the YD in the inner SBFD packet is 20, and the session state in the inner SBFD packet is UP.

[0130] Based on the SRH included in SBFD probe packet 5, forwarding node R4 updates the DA in the outer IPv6 header of SBFD probe packet 5 to the SID of forwarding node R5, thus obtaining SBFD probe packet 6, and sends it.

[0131] Based on the SRH included in SBFD probe packet 6, forwarding node R5 updates the DA of the outer IPv6 header in SBFD session negotiation packet 6 to 5::5, resulting in SBFD probe packet 7. Forwarding node R5 discovers that the DA of the outer IPv6 header in SBFD probe packet 7 is 5::5, which is the local address of forwarding node R5. It then identifies the inner SBFD packet based on the UDP port number, where YD is the session local identifier 20 of forwarding node R5. It performs SBFD reflection processing, that is, swapping the source and destination addresses in the outer IPv6 header of SBFD probe packet 7, and swapping the MD and YD included in the inner SBFD packet, resulting in SBFD probe packet 8, which is then sent to forwarding node R1.

[0132] When the message receiving module of forwarding node R1 receives SBFD probe message 8, it identifies the inner SBFD message, YD is the session local identifier 200 of forwarding node R1, and the session status is UP. It then resets the timeout duration of the SBFD session corresponding to session local identifier 200 to prevent the SBFD session from timeout and going down.

[0133] In application scenarios with ring paths, such as network security resource pools, the technical solution provided in this application can overcome the shortcomings of existing SBFD solutions, improve the reliability of service deployment in these scenarios, and ensure the proper implementation of the solution. The technical solution provided in this application can be used in service scenarios with ring networks or ring paths.

[0134] Furthermore, in the technical solution provided in this application embodiment, when the head node of the ring path performs SBFD, it constructs an SBFD message according to the format of the reflecting end (i.e., the tail node), simulates the sending of the SBFD message by the reflecting end, and then performs reception processing on the SBFD message. That is, the head node of the ring path only needs to perform the operation of sending and receiving SBFD messages, without performing the operation of reflecting SBFD messages. With SBFD implemented on the ring path, the operations performed by the forwarding nodes are reduced, and the pressure on the forwarding nodes is reduced. Moreover, after the SBFD session negotiation is successful, when the session distribution submodule sends the session parameters to the session maintenance submodule, it swaps the positions of the session local identifier and the session reflecting end identifier, making the ring path SBFD probing transparent to the session maintenance submodule, and the session maintenance submodule does not need to be modified.

[0135] This application also provides a forwarding node, such as... Figure 9 As shown, it includes a processor 901, a communication interface 902, a memory 903, and a communication bus 904, wherein the processor 901, the communication interface 902, and the memory 903 communicate with each other through the communication bus 904.

[0136] Memory 903 is used to store computer programs;

[0137] The processor 901, when executing the program stored in the memory 903, implements any of the above-mentioned seamless bidirectional forwarding detection methods.

[0138] The communication bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0139] The communication interface is used for communication between the aforementioned forwarding nodes and other devices.

[0140] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0141] The processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it 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, or discrete hardware components.

[0142] In another embodiment provided in this application, a computer-readable storage medium is also provided, which stores a computer program that, when executed by a processor, implements any of the above-described seamless bidirectional forwarding detection methods.

[0143] In another embodiment provided in this application, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to perform any of the above-described seamless bidirectional forwarding detection methods.

[0144] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0145] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0146] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments for forwarding nodes, storage media, and program products are basically similar to the method and apparatus embodiments, and therefore the descriptions are relatively simple; relevant parts can be referred to the descriptions of the method and apparatus embodiments.

[0147] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A seamless bidirectional forwarding detection method, characterized in that, The method, applied to a forwarding node initiating SBFD, wherein the session-local identifier and the session-reflecting identifier on the forwarding node are different, includes: When the path to be detected is a ring path, a first SBFD message is generated. The first SBFD message includes a first remote identifier field, which carries the session local identifier on the forwarding node. The first SBFD message is sent along the ring path, causing the first SBFD message to be forwarded along the ring path and return to the forwarding node.

2. The method of claim 1, wherein, The first SBFD message is an SBFD session negotiation message; the SBFD session negotiation message also includes a first local identifier field, which carries the session reflection identifier on the forwarding node, and the session state in the SBFD session negotiation message is set to the UP state.

3. The method of claim 1, wherein, The first SBFD message is an SBFD probe message; the forwarding node configures the remote identifier contained in the SBFD probe message to be the session local identifier on the forwarding node, and the session state in the SBFD probe message is set to UP state.

4. The method of claim 3, wherein, The forwarding node configures the local identifier contained in the SBFD probe message to be the session reflection endpoint identifier on the forwarding node. The SBFD probe message also includes a second local identifier field, which carries the session reflection identifier on the forwarding node.

5. The method according to claim 1, characterized in that, The step of generating the first SBFD message when the path to be detected is a loop path includes: Detect whether the path to be probed is configured with a ring parameter; if the ring parameter is configured, generate a first SBFD message; or, Detect whether the tail node of the path to be probed is the forwarding node; if it is the forwarding node, generate the first SBFD message.

6. The method according to any one of claims 1-5, characterized in that, The method further includes: When the path to be detected is a non-circular path, a second SBFD message is generated. The second SBFD message includes a second remote identifier field, which carries the session reflection end identifier on the forwarding node. The second SBFD message is sent along the non-circular path.

7. A seamless bidirectional forwarding detection apparatus, characterized by, An apparatus for use with a forwarding node initiating SBFD, wherein the session-local identifier and the session-reflecting identifier on the forwarding node are different; the apparatus includes: The message generation module is used to generate a first SBFD message when the path to be detected is a ring path. The first SBFD message includes a first remote identifier field, which carries the session local identifier on the forwarding node. The message sending module is used to send the first SBFD message along the ring path, so that the first SBFD message is forwarded along the ring path and returns to the forwarding node.

8. The apparatus of claim 7, wherein, The first SBFD message is an SBFD session negotiation message; the message generation module includes a session negotiation submodule; the session reflection end identifier in the session negotiation submodule is the session reflection end identifier on the forwarding node, and the session local end identifier in the session negotiation submodule is the session local end identifier on the forwarding node; The session negotiation submodule is used to generate the SBFD session negotiation message based on the session reflection end identifier and the session local end identifier in the session negotiation submodule when the path to be detected is a ring path. The SBFD session negotiation message also includes a first local end identifier field, which carries the session reflection end identifier in the session negotiation submodule. The first remote end identifier field carries the session local end identifier in the session negotiation submodule. The session state in the SBFD session negotiation message is set to UP state.

9. The apparatus of claim 7, wherein, The first SBFD message is an SBFD probe message; the message generation module includes a session delivery submodule and a session maintenance submodule; The session delivery submodule is used to configure the session local identifier on the forwarding node as the session reflection identifier to the session maintenance submodule. The session maintenance submodule is used to generate the SBFD probe message based on the session reflection endpoint identifier in the session maintenance submodule. The first remote identifier field carries the session reflection endpoint identifier in the session maintenance submodule, and the session state in the SBFD probe message is set to UP state.

10. The apparatus of claim 9, wherein, The session delivery submodule is also configured to use the session reflection endpoint identifier on the forwarding node as the session local endpoint identifier and configure it to the session maintenance submodule. The session maintenance submodule is specifically used to generate the SBFD probe message based on the session reflection end identifier and the session local end identifier in the session maintenance submodule. The SBFD probe message also includes a second local end identifier field, which carries the session local end identifier in the session maintenance submodule.

11. The apparatus according to claim 7, characterized in that, The message generation module includes a session negotiation submodule; The session negotiation submodule is specifically used to: detect whether the path to be probed is configured with a ring parameter; if the ring parameter is configured, generate a first SBFD message; or, detect whether the tail node of the path to be probed is the forwarding node. If it is the forwarding node, then a first SBFD message is generated.

12. The apparatus according to any one of claims 7-11, characterized in that, The message generation module is further configured to generate a second SBFD message when the path to be detected is a non-ring path. The second SBFD message includes a second remote identifier field, which carries the session reflection end identifier on the forwarding node. The message sending module is also used to send the second SBFD message along the non-circular path.

13. A forwarding node, characterized by, It includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, when executing a program stored in memory, implements the method of any one of claims 1-6.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method described in any one of claims 1-6.

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