BFD session management method and device

Abstract

The invention discloses a BFD session management method and device, and the method comprises the steps: responding to a creation instruction for a first segment list, enabling the first segment list to be matched with a second segment list in a BFD session statistical table, enabling a first endpoint to be matched with a second endpoint in an FD session statistical table, and enabling a first BFD session attribute to be matched with a second BFD session attribute in the FD session statistical table, and subscribing a detection state of a first BFD session for the first segment list. According to the method and the device for detecting the BFD session, the SR policy session list reaching the same endpoint, the same session list and the same BFD session attribute is supported, and the detection result of the same BFD session is multiplexed, so that the resources of the BFD session are saved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a method and device for managing a BFD session. Background Art

[0002] Currently, bidirectional forwarding detection (BFD) supports segment routing (SR) policy detection function. Network devices create BFD sessions based on segment list granularity to detect the reachability of each segment list under the primary candidate path (CP) in the SR policy and the reachability of each segment list under the backup candidate path in the SR policy.

[0003] Currently, when the endpoints, segment list segment ID (SID) stacks, and BFD session attributes are the same, SR policy creates a BFD session for each segment list. This results in the need to create a large number of BFD sessions, wasting BFD session resources. Summary of the invention

[0004] The present application provides a BFD session management method and device, which can save BFD session resources. The technical solution is as follows.

[0005] In a first aspect, a method for managing a BFD session is provided, the method comprising: in response to a creation instruction for a first segment list segment list, a network device obtaining the first segment list, a first endpoint endpoint and a first BFD session attribute, wherein the first endpoint is a destination address of the first segment list, and the first BFD session attribute is a BFD session attribute to be enabled for the first segment list; the network device searches a segment routing policy SRpolicy BFD session statistics table based on the first segment list, the first endpoint and the first BFD session attribute, the SR policy BFD session statistics table comprising a first record, the first record comprising a second segment list, a second endpoint, a second BFD session attribute and a detection status of the first BFD session; in response to the first segment list matching the second segment list, the first endpoint matching the second endpoint and the first BFD session attribute matching the second BFD session attribute, the network device subscribes to the detection status of the first BFD session for the first segment list.

[0006] Based on the method of the first aspect, in the scenario where BFD supports SR policy segment list detection, it supports SR policy segment lists that reach the same endpoint, the same segment list, and the same BFD session attributes, and reuses the detection results of the same BFD session. In other words, multiple segment lists with the same endpoint, the same segment list, and the same BFD attributes of the SR policy share one BFD session, or the number of BFD sessions occupied by the SR policy is less than the number of segment lists currently using BFD for detection, thereby saving BFD session resources.

[0007] For example, for three segment lists that reach the same endpoint, have the same BFD session attributes, and have the same segment lists, only one BFD session needs to be created, thus saving the resources of two BFD sessions.

[0008] Furthermore, since the number of BFD sessions is saved, the processing burden of the CPU of the network device caused by periodically sending a detection message for each BFD session and the occupation of the memory space for maintaining each BFD session are also reduced.

[0009] In a possible implementation, the first record includes an identifier of the first BFD session and a first field, and the network device subscribes to the detection status of the BFD session for the first segment list, including: the network device adds the identifier of the first segment list to the first field in the first record; the network device stores the identifier of the first BFD session under the first segment list.

[0010] In one possible implementation, the method also includes: in response to an update of the detection status of the BFD session, the network device obtains an identifier of the first segment list from the first record; and the network device updates the status of the first segment list based on the updated detection status of the BFD session and the identifier of the first segment list.

[0011] In a possible implementation, the method also includes: in response to a delete instruction for the first segment list, the network device obtains an identifier of the first BFD session stored under the segment list; the network device searches the SR policy BFD session statistics table based on the identifier of the first BFD session; in response to the identifier of the first BFD session hitting the first record, the network device deletes the identifier of the first segment list from the first field in the first record.

[0012] In a possible implementation manner, the first record includes an identifier of the first BFD session and a first field, and the network device subscribes to a detection status of the BFD session for the first segment list, including:

[0013] The network device adds the address pointer of the first segment list to the first field in the first record;

[0014] The network device stores the address pointer of the first record under the first segment list.

[0015] In a possible implementation, the method further includes:

[0016] In response to an update of the detection state of the BFD session, the network device obtains an address pointer of the first segment list from the first record;

[0017] The network device updates the state of the first segment list based on the updated detection state of the BFD session and the address pointer of the first segment list.

[0018] In one possible implementation, the method also includes: in response to a delete instruction for the first segment list, the network device obtains the address pointer of the first record stored under the segment list; the network device searches the SR policy BFD session statistics table based on the address pointer of the first record; in response to the address pointer of the first record pointing to the first record in the SR policy BFD session statistics table, the network device deletes the address pointer of the first segment list from the first field in the first record.

[0019] In one possible implementation, the method also includes: in response to the first segment list, the first endpoint, and the first BFD session attributes not completely matching the segment list, endpoint, and BFD session attributes in each record in the SR policy BFD session statistics table, the network device creates a second BFD session and subscribes to the detection status of the second BFD session for the first segment list.

[0020] In a possible implementation manner, the method further includes: in response to the length of the first field being zero, the network device deletes the first record and deletes the session identifier of the first BFD session.

[0021] In a possible implementation, the network device is a head node of a forwarding path indicated by the first segment list.

[0022] In a possible implementation, the first BFD session attribute includes a first SBFD enable bit, a first single-arm BFD enable bit, a first backhaul in-segment list enable bit, a first non-protected path enable bit, a first minimum sending interval, and a first detection multiplier; the second BFD session attribute includes a second SBFD enable bit, a second single-arm BFD enable bit, a second backhaul in-segment list enable bit, a second non-protected path enable bit, a second minimum sending interval, and a second detection multiplier; in response to the first segment list matching the second segment list, the first endpoint matching the second endpoint, and the first BFD session attribute matching the second BFD session attribute, the network device subscribing to the detection status of the first BFD session for the first segment list includes:

[0023] In response to the first segment list being the same as the second segment list, the first endpoint being the same as the second endpoint, the first SBFD enable bit being the same as the second SBFD enable bit, the first single-arm BFD enable bit being the same as the second single-arm BFD enable bit, the first backhaul in-segment list enable bit being the same as the second backhaul in-segment list enable bit, the first non-protected path enable bit being the same as the second non-protected path enable bit, the first minimum sending interval being the same as the second minimum sending interval, and the first detection multiplier being the same as the second detection multiplier, the network device subscribes to the detection status of the first BFD session for the first segment list.

[0024] In a second aspect, a management device for a bidirectional forwarding detection (BFD) session is provided, the device comprising:

[0025] an acquisition unit, configured to acquire, in response to a creation instruction for a first segment list segment list, the first segment list, a first endpoint endpoint, and a first BFD session attribute, wherein the first endpoint is a destination address of the first segment list, and the first BFD session attribute is a BFD session attribute to be enabled for the first segment list;

[0026] A processing unit, configured to search a segment routing policy SR policy BFD session statistics table based on the first segment list, the first endpoint, and the first BFD session attributes, wherein the SR policy BFD session statistics table includes a first record, wherein the first record includes a second segment list, a second endpoint, a second BFD session attribute, and a detection status of the first BFD session; in response to the first segment list matching the second segment list, the first endpoint matching the second endpoint, and the first BFD session attribute matching the second BFD session attribute, subscribing the detection status of the first BFD session for the first segment list.

[0027] In a possible implementation, the first record includes an identifier of the first BFD session and a first field, and the processing unit is used to add the identifier of the first segment list to the first field in the first record; and store the identifier of the first BFD session under the first segment list.

[0028] In a possible implementation, the processing unit is further used to obtain the identifier of the first segment list from the first record in response to an update of the detection status of the BFD session; and update the status of the first segment list based on the updated detection status of the BFD session and the identifier of the first segment list.

[0029] In a possible implementation, the processing unit is further used to obtain the identifier of the first BFD session stored under the segment list in response to a delete instruction for the first segmentlist; search the SR policy BFD session statistics table based on the identifier of the first BFD session; and delete the identifier of the first segment list from the first field in the first record in response to the identifier of the first BFD session hitting the first record.

[0030] In a possible implementation, the first record includes an identifier of the first BFD session and a first field, and the processing unit is used to add an address pointer of the first segment list to the first field in the first record; and store the address pointer of the first record under the first segment list.

[0031] In a possible implementation, the processing unit is also used to obtain the address pointer of the first segment list from the first record in response to an update of the detection status of the BFD session; and update the status of the first segment list based on the updated detection status of the BFD session and the address pointer of the first segment list.

[0032] In a possible implementation, the processing unit is also used to obtain the address pointer of the first record stored under the segment list in response to a delete instruction for the first segmentlist; search the SR policy BFD session statistics table based on the address pointer of the first record; and in response to the address pointer of the first record pointing to the first record in the SR policy BFD session statistics table, delete the address pointer of the first segment list from the first field in the first record.

[0033] In one possible implementation, the processing unit is also used to create a second BFD session and subscribe to the detection status of the second BFD session for the first segment list in response to the first segment list, the first endpoint, and the first BFD session attributes not fully matching the segment list, endpoint, and BFD session attributes in each record in the SR policy BFD session statistics table.

[0034] In a possible implementation manner, the processing unit is further configured to, in response to a length of the first field being zero, delete the first record and delete the session identifier of the first BFD session.

[0035] In a possible implementation manner, the device is arranged at a head node of a forwarding path indicated by the first segment list.

[0036] In a possible implementation, the first BFD session attribute includes a first SBFD enable bit, a first single-arm BFD enable bit, a first backhaul in-segment list enable bit, a first non-protected path enable bit, a first minimum sending interval, and a first detection multiplier; the second BFD session attribute includes a second SBFD enable bit, a second single-arm BFD enable bit, a second backhaul in-segment list enable bit, a second non-protected path enable bit, a second minimum sending interval, and a second detection multiplier; in response to the first segment list matching the second segment list, the first endpoint matching the second endpoint, and the first BFD session attribute matching the second BFD session attribute, the processing unit is further configured to, in response to the first segment list being the same as the second segment list, the first endpoint being the same as the second endpoint, the first SBFD enable bit being the same as the second SBFD enable bit, the first single-arm BFD enable bit being the same as the second single-arm BFD enable bit, the first backhaul in-segment list enable bit being the same as the second backhaul in-segment list enable bit. The first segment list enable bit is the same, the first non-protected path enable bit is the same as the second non-protected path enable bit, the first minimum sending interval is the same as the second minimum sending interval, and the first detection multiplier is the same as the second detection multiplier, subscribing the first segment list to the detection status of the first BFD session.

[0037] In a third aspect, a network device is provided, the network device comprising a processor, the processor being coupled to a memory, the memory storing at least one computer program instruction, the at least one computer program instruction being loaded and executed by the processor, so that the network device implements the method provided in the first aspect or any optional manner of the first aspect. The specific details of the network device provided in the third aspect can be found in the first aspect or any optional manner of the first aspect, and will not be repeated here.

[0038] In a fourth aspect, a computer-readable storage medium is provided, wherein at least one instruction is stored in the storage medium. When the instruction is executed on a computer, the computer executes the method provided by the first aspect or any optional manner of the first aspect.

[0039] In a fifth aspect, a computer program product is provided, which includes one or more computer program instructions. When the computer program instructions are loaded and executed by a computer, the computer executes the method provided by the first aspect or any optional manner of the first aspect.

[0040] In a sixth aspect, a chip is provided, comprising a memory and a processor, wherein the memory is used to store computer instructions, and the processor is used to call and run the computer instructions from the memory to execute the method in the above-mentioned first aspect and any possible implementation of the first aspect.

[0041] Based on the implementations provided in the above aspects, this application can also be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic diagram of the SR policy tunnel model provided in an embodiment of the present application;

[0043] Figure 2 It is a flowchart of an SRv6 policy BFD session management method provided in an embodiment of the present application;

[0044] Figure 3 It is a structural diagram of a BFD session management device 300 provided in an embodiment of the present application;

[0045] Figure 4 It is a structural diagram of a network device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0047] The following is an explanation of some terminology concepts involved in the embodiments of the present application.

[0048] (1)BFD

[0049] BFD is used to quickly detect the connectivity of the forwarding path of traffic in the network in both directions. When a forwarding path failure is detected, it quickly notifies the upper-layer application that the forwarding path is in a faulty state. In response to the forwarding path failure, the upper-layer application quickly switches the forwarding path to avoid service interruption.

[0050] (2) Seamless Bidirectional Forwarding Detection (SBFD)

[0051] SBFD technology simplifies BFD. In SBFD technology, the roles of devices are divided into initiators and reflectors. The initiator is used to create SBFD sessions and send SBFD detection messages. The reflector is used to loop back the SBFD detection messages sent by the initiator. When the initiator detects a forwarding path failure, it notifies the upper-layer application that the forwarding path is faulty. In response to the forwarding path failure, the upper-layer application quickly switches the forwarding path to avoid service interruption.

[0052] (3) Single-arm BFD

[0053] In the one-arm BFD technology, the roles of the devices are divided into initiator and reflector. The initiator is used to create a one-arm BFD session and send one-arm BFD detection messages. The source IP address and destination IP address in the IP header of the one-arm BFD detection message are both the Internet Protocol (IP) address of the initiator device. The local identifier (my discriminator, MD) and remote identifier (your discriminator, YD) filled in the one-arm BFD detection message are also the same. After the reflector receives the one-arm BFD detection message, the reflector queries the IP routing table based on the destination IP address of the one-arm BFD detection message and forwards the one-arm BFD detection message back to the initiator. Therefore, in the one-arm BFD technology, the reflector only needs to support IP forwarding, but the initiator and the reflector are required to be in the same network segment.

[0054] (4) SBFD supports SR policy

[0055] The head node of the SR policy is the initiator of SBFD. The tail node of the SR policy is the reflector of SBFD. The head node of the SRpolicy (the initiator of SBFD) creates an SBFD session according to the segment list. The head node of the SR policy generates and sends an SBFD detection message. The SBFD detection message includes a segment list. The head node of the SR policy forwards the SBFD detection message according to the forwarding path indicated by the segment list. The intermediate node of the SR policy forwards the SBFD detection message to the tail node of the SR policy (the reflector of SBFD) according to the forwarding path indicated by the segment list in the SBFD detection message. After the reflector of SBFD generates the return SBFD detection message, it forwards the SBFD detection message back to the initiator of SBFD by IP routing according to the destination IP address of the SBFD detection message.

[0056] (5) One-arm BFD supports SR policy

[0057] SBFD supports SR policy by configuring the mapping relationship between the IP address of the SBFD reflector and the descriptor of the SBFD reflector on the head node of SR policy (the initiator of SBFD). In addition, the same descriptor of the SBFD reflector is configured on the SBFD reflector. When the SBFD reflector does not support SBFD or it is inconvenient to deploy SBFD on the SBFD reflector, you can configure one-arm BFD to support SR policy.

[0058] (6) Return to the segment list

[0059] The return entry segment list is a BFD session attribute. The return entry segment list means that during the BFD detection message return (the BFD reflector sends the BFD detection message to the BFD initiator), the BFD detection message includes the segment list, and the BFD detection message is forwarded from the BFD reflector to the BFD initiator according to the path indicated by the SID in the segment list. BFD (such as SBFD or one-arm BFD) can support the SR policy detection message return entry segment list, thereby solving the BFD detection message return co-path problem.

[0060] Specifically, during the outbound BFD detection message (the initiator of BFD sends the BFD detection message to the reflector of BFD), the BFD detection message may include a segment list, and the initiator of BFD may forward the BFD detection message along the path corresponding to the segment list according to the segment list. After the reflector of BFD receives the BFD detection message, if the return entry segment list method is not adopted, the reflector of BFD and the intermediate node may forward the BFD detection message by IP routing based on the destination IP address of the BFD detection message, resulting in that the BFD detection messages for multiple different segment list paths may pass through the same IP path during the return trip, and when the return path fails, it will cause BFD false alarms. For this scenario, when the BFD detection message is returned, the BFD reflector adds the segment list to the BFD detection message, so that the BFD detection message is forwarded to the initiator of BFD through the path specified by the segment list, thereby reducing the risk of BFD false alarms caused by the common path of the BFD detection message return trip.

[0061] (7) Not passing through the protection path

[0062] Not passing through the protection path is a BFD session attribute. BFD (SBFD or one-arm BFD) can support SR policy detection messages not passing through the protection path. If there is a protection path in the segment list detected by BFD, such as a Topology Independent Loop-Free Alternate (TI-LFA) path or a Traffic Engineering Fast Reroute (TE FRR) path, when there is a fault in the segment list path, the BFD detection message can be forwarded by bypassing the protection path, bypassing the fault point, thereby causing the segment list status to remain up (connected), which may not be consistent with the user's actual expectations. The above problem can be solved by supporting BFD detection messages not passing through the protection path. When there is a fault in the path determined by the segment list, BFD can quickly detect and report it, triggering the service to switch to the backup path.

[0063] (8)SR policy supports independent configuration of BFD detection parameters for the backup candidate path

[0064] When the BFD detection parameters of the primary candidate path of the SR policy are the same as those of the backup candidate path, in the scenario where the BFD detection message return path is shared, the primary candidate path and the backup candidate path of the SR policy are both in the down (disconnected) state due to the return path failure, resulting in service interruption. By increasing the BFD detection parameters of the backup candidate path, the path under the backup candidate path is kept in the up state. When the routing convergence IP is reachable again, the service is still forwarded through the backup candidate path to avoid service interruption.

[0065] (9) SR policy tunnel model

[0066] Attached Figure 1is a schematic diagram of the SR policy tunnel model provided in the embodiment of the present application. An SR policy consists of a tuple<headend,color,endpoint> For a specified head node, the SR policy is<color,endpoint> Identification. The headend is used to indicate the node generated by the SRv6 policy. The headend is generally a globally unique IP address. Color is an extended community attribute with a length of 32 bits. Color is used to identify a certain service intent (such as low latency). The end point is the destination address of the SRv6 policy. The endpoint is generally a globally unique IP address. For example, the endpoint is the address of the last SID in the segment list in the SR policy.

[0067] (10) Minimum transmission interval (min-tx-interval)

[0068] The minimum sending interval is used to indicate the time interval for sending BFD probe messages. For example, the minimum sending interval is the minimum value of the time difference between the sending time points of two adjacent BFD probe messages. The smaller the value of the minimum sending interval, the shorter the sending interval between BFD probe messages, and the faster the BFD fault detection speed. Exemplarily, the minimum sending interval is the value of the SBFDmin-tx-interval parameter. Exemplarily, if the value of the minimum sending interval is set to 100 milliseconds, the BFD session initiator will send a BFD probe message to the BFD session reflector every 100 milliseconds.

[0069] (11) Detect-multiplier

[0070] The detection multiple is used to indicate the maximum number of consecutive packet losses that the sender is allowed to send BFD detection messages. The detection multiple specifies the maximum time interval to wait when no response is received from the peer end. The detection multiple determines the timeout period for fault detection. For example, the minimum sending interval is t, and the detection multiple is k times the minimum sending interval, which means that when the time duration for which no BFD detection message is received from the peer end exceeds (t*k), the link is determined to be in a faulty state. Exemplarily, configure the detect-multiplier to 3 and the min-tx-interval to 100 milliseconds, then the path is determined to be in a faulty state when no BFD message is received from the peer end for more than 300 milliseconds.

[0071] (12) BFD session attributes

[0072] The BFD session attributes include at least one of the BFD type, whether the return tunnel is enabled, the enable bit for not passing through the protection path, the minimum sending interval, and the detection multiplier. BFD types include SBFD and single-arm BFD. For example, the BFD session attributes include the SBFD enable bit and the single-arm BFD enable bit. The SBFD enable bit is used to identify whether SBFD is enabled. For example, when the SBFD enable bit is the first value, it indicates that SBFD is enabled, and when the SBFD enable bit is the second value, it indicates that SBFD is not enabled. The single-arm BFD enable bit is used to identify whether single-arm BFD is enabled. For example, when the single-arm BFD enable bit is the first value, it indicates that single-arm BFD is enabled, and when the single-arm BFD enable bit is the second value, it indicates that SBFD is not enabled. Whether the return tunnel is enabled is used to indicate whether the BFD detection message is forwarded through a specific tunnel during the return. For example, whether the return tunnel is enabled is the return in-segment list enable bit. The return entry segment list enable bit is used to identify whether the BFD detection message return entry segment list is enabled. For example, when the return entry segment list enable is the first value, it indicates that the BFD detection message return entry segment list is enabled. When the return entry segment list enable is the second value, it indicates that the BFD detection message return entry segment list is not enabled. The non-protection path enable bit is used to identify whether the BFD detection message is enabled to not pass through the protection path. For example, when the non-protection path enable bit is the first value, it indicates that the BFD detection message is enabled to not pass through the protection path, and when the non-protection path enable bit is the second value, it indicates that the BFD detection message is not enabled to not pass through the protection path. In one possible implementation, the BFD session attributes are recorded through the BFD session statistics table. For example, the BFD session attributes are recorded through the session attribute (session attribute) subtable in the BFD session statistics table.

[0073] (13) BFD session statistics table

[0074] The BFD session statistics table is used to record the detection status of each BFD session that has been created. For example, the BFD session statistics table is the SR policy BFD session statistics table. The SR policy BFD session statistics table is used to record the BFD detection status of the BFD session created for each segment list under each candidate path under the SR policy. For example, a record in the SR policy BFD session statistics table includes the segment list, the endpoint corresponding to the segment list, the BFD session attributes, and the BFD detection status. The BFD session statistics table includes the SR policy BFD session statistics table and the SR-MPLS TE policy BFD session statistics table.

[0075] (14) Reference tree

[0076] The reference tree is used to record the identifiers of the segment lists that subscribe to the BFD session. The data structure of the reference tree is a tree.

[0077] (15) Reference list

[0078] The reference list is used to record the identifier of the segment list that subscribes to the BFD session. The data structure of the reference list is a linked list.

[0079] (16)BFD session ID

[0080] The session ID is used to uniquely identify a BFD session. In a possible implementation, a session ID uniquely corresponds to a record in the BFD session statistics table.

[0081] The following is an example of an application scenario of the embodiment of the present application.

[0082] Currently, BFD supports the SR policy detection function. Network devices create BFD sessions based on the segment list granularity to detect the reachability of each segment list under the primary candidate path in the SR policy and the reachability of each segment list under the backup candidate path in the SR policy. For example, if the SR policy includes the following four segment lists, and each segment list has hot standby enabled, a total of 4 SBFD session resources are required.

[0083]

[0084] Currently, BFD session resources are shared by all features. BFD session resources are in short supply. SR policy currently creates a BFD session for each segment list when the endpoints are the same, the SID stacks of the segment lists are the same, and the BFD session attributes are the same. This wastes BFD session resources and increases the system burden.

[0085] Specifically, whenever a network device creates a BFD session, the network device needs to maintain the state of the BFD session, and the state of the BFD session includes initialization, negotiation, or detection. The network device needs to occupy timer resources and memory space to maintain the state of the BFD session. In addition, whenever a network device creates a BFD session, the network device needs to periodically generate and send a probe message. For example, for a BFD session, the network device generates and sends a probe message every 30 milliseconds, and both generating and sending a probe message consume CPU processing resources, resulting in more CPU processing resources being consumed. As the number of BFD sessions increases, the consumption of CPU resources will also increase.

[0086] It can be seen that if a BFD session is created for each segment list, there will be a large number of BFD sessions, which may easily lead to unnecessary waste of BFD session resources. For example, three segment lists are configured for the same endpoint (equivalent to the same destination address), and the three segment lists are the same, and the BFD session attributes corresponding to the three segment lists are the same (for example, the BFD session attributes corresponding to the three segment lists are all SBFD sessions or single-arm BFD sessions). Currently, three BFD sessions will be created for the three segment lists. These three BFD sessions actually detect the quality of the same forwarding path, and maintaining the three BFD sessions consumes more resources.

[0087] In view of this, an embodiment of the present application provides a method for managing a BFD session. In a scenario where BFD supports SR policy segment list detection, it supports SR policy segment lists that reach the same endpoint, the same segment list, and the same BFD session attributes, and reuses the detection results of the same BFD session. In other words, multiple segment lists with the same endpoint, the same segment list, and the same BFD attributes of the SR policy share one BFD session, or the number of BFD sessions occupied by the SR policy is less than the number of segment lists currently using BFD for detection. For example, for three segment lists that reach the same endpoint, have the same BFD session attributes, and have the same segment list, only one BFD session needs to be created, thereby saving the resources of two BFD sessions.

[0088] The BFD session management method provided in the embodiment of the present application can be applied to network devices, such as network devices such as routers, switches or firewalls. For example, the BFD session management method can be applied to a provider edge device (Provider Edge, PE). For example, the BFD session management method can be applied to the initiator (head node of the SR policy tunnel) of BFD (such as single-arm BFD or SBFD) that supports SR policy.

[0089] The detection result of the BFD session is, for example, the BFD detection state recorded in the BFD session statistics table, and the BFD detection state is, for example, the state of the BFD state machine. The BFD detection state includes but is not limited to the initial state, the up state, and the down state. The state of the BFD session detection is obtained through the state field in the BFD detection message.

[0090] The BFD session management method provided in the embodiment of the present application can be applied to a segment routing (internet protocol version 6for segment routing, SRv6) scenario based on Internet Protocol version 6, and can also be applied to a segment routing multi-protocol for label switching (segment routing multi-protocol for label switching, SRMPLS) scenario.

[0091] In particular, in large-scale scenarios, such as some test scenarios, BFD sessions may be created for many segment lists with the same endpoint and the same BFD attributes, resulting in a large number of BFD sessions, while the number of BFD sessions that a device can maintain is limited. For example, a device can usually only maintain 16,000 BFD sessions. Creating a BFD session for each segment list causes the BFD session resources to be fully occupied, which puts a lot of pressure on the device and also limits the possibility of using BFD session resources for other features other than SR policy segment list detection. Based on the method provided in this embodiment, only one BFD session needs to be created for the same endpoint, the same BFD attribute, and the same segment list. Therefore, a small number of BFD sessions can meet the needs of the test scenario, thereby saving a large number of BFD session resources and reserving more BFD session resources for other features other than SR policy segment list detection.

[0092] The following is an example of an application scenario of the embodiment of the present application.

[0093] Figure 1 Schematic diagram of the application scenario provided by the embodiment of the present application. Figure 1 In the scenario shown, Custom Edge routers (CE) 1, R1, R2, R3, and CE2 are deployed. Customer services accessing R1 from CE1 are divided into three categories, namely, Class A security monitoring services, Class B voice services, and Class C data services.

[0094] Deploy SR policy on router R1. SR policy is used to carry customer services. SR policy path reachability is detected through SBFD. Colors can be used to map different service categories. For example, color 1000 maps class A security monitoring services, color 2000 maps class B voice services, and color 3000 maps class C data services.

[0095] The BFD session management method provided in this embodiment can be deployed on the head node R1 of the SR policy. Three SRpolicy tunnels share one SBFD session, thereby saving BFD resources.

[0096]

[0097] The above configuration means that segment list1 defines a segment list, which includes SID (SegmentIdentifier) ​​1. SR policy policy1 specifies the endpoint as R3, the color as 1000, and maps it to Class A services. In addition, candidate path 200 specifies the path selection list as list1. At the same time, the SR policy is associated with sbfdsession1. SR policy policy2 specifies the endpoint as R3, the color as 2000, and maps it to Class B services. In addition, candidate path200 specifies the path selection list as list1. At the same time, the SR policy is associated with sbfdsession1. SR policy policy3 specifies the endpoint as R3, the color as 3000 (mapped to Class C services), and specifies the path selection list as list1 through candidate path 200. At the same time, the SR policy is associated with sbfdsession1.

[0098] The following is an example of the method flow provided in the embodiment of the present application. This embodiment involves a process of matching a newly created segment list with a segment list recorded in a BFD session statistics table. In order to distinguish the description, the following uses "first segment list" to describe the newly created segment list, "first BFD session attribute" to describe the BFD session attribute to be enabled for the newly created segment list, "first endpoint" to describe the endpoint corresponding to the newly created segmentlist, "second segment list" to describe the segmentlist in a record in the BFD session statistics table, "second BFD session attribute" to describe the BFD session attribute corresponding to the segment list in the record in the BFD session statistics table, and "second endpoint" to describe the endpoint corresponding to the segment list in the record in the BFD session statistics table.

[0099] Example 1

[0100] Example 1 is an implementation example of a method for managing a BFD session in an SRv6 policy scenario. Example 1 involves the application of an SRv6policy BFD session statistics table and an SRv6 policy BFD session attribute subtable.

[0101] The SRv6 policy BFD session statistics table is used to record the correspondence between the detection results of the BFD session used by each segment list in the SRv6 policy and the segment list that subscribes to the BFD session. Each record in the SRv6 policy BFD session statistics table includes a key (key or index) field and a value field. The key field includes table key1 and table key2. Table key1 includes endpoint, segment list, and BFD session attribute (session attribute). The network device can uniquely index a record in the SRv6 policy BFD session statistics table based on table key1. Table key2 includes the session identifier (session ID) of the BFD session. The network device can uniquely index a record in the SRv6 policy BFD session statistics table based on the session ID. Table key1 and table key2 can be used either one. The value field in each record in the SRv6 policy BFD session statistics table includes the BFD detection state (BFD state) of a BFD session and one or more segment list IDs that subscribe to the BFD session. Each segment list ID is used to identify a segment list that subscribes to the corresponding BFD session.

[0102] With respect to the data structure carrying the segment list ID in the SRv6 policy BFD session statistics table, in one possible implementation, the SRv6 policy BFD session statistics table includes a reference tree field, and the reference tree field is used to store the segment list IDs of one or more segment lists subscribed to the BFD session. In another possible implementation, the SRv6 policy BFD session statistics table includes a reference list field, and the reference list field is used to store the segment list IDs of one or more segment lists subscribed to the BFD session.

[0103] The BFD session attributes included in table key1 can be defined by the session attribute subtable. The session attribute subtable includes SBFD enable bit, one-arm BFD enable bit, return in-segment list enable bit, no protection path enable bit, minimum transmission interval (e.g., SBFD min-tx-interval value), and detection multiplier (e.g., SBFD detect-multiplier value).

[0104] In a possible implementation, a session ID corresponding to the segment list in the BFD session statistics table is stored under the segment list under the candidate path under the SRv6 policy, and the session ID identifies the BFD session subscribed by the segment list.

[0105] The following describes the processing logic of managing SRv6 policy BFD sessions on network devices in combination with the above SRv6 policy BFD session statistics table. Figure 2 , attached Figure 2 This is a flowchart of an SRv6policy BFD session management method provided in an embodiment of the present application, Figure 2 The method shown includes the following steps.

[0106] Step S210: The network device receives an instruction to create a first segment list, and obtains the first segment list, a first BFD session attribute enabled for the first segment list, and a first endpoint corresponding to the first segment list.

[0107] The creation instruction instructs a candidate path in an SRv6 policy to create a new first segmentlist. The creation instruction may be input through a command line or a web interface. The creation instruction may include the first segmentlist, the first BFD session attribute, and the first endpoint.

[0108] Since the first segment list, the first BFD session attribute, and the first endpoint are obtained in step S210, it is convenient to determine whether the condition for multiplexing the BFD session is met based on the first segment list, the first BFD session attribute, and the first endpoint.

[0109] In a possible implementation, the network device also obtains the state of the BFD switch corresponding to the SRv6 policy. The state of the BFD switch is used to indicate whether BFD is enabled. If the state of the BFD switch is on, the network device performs step S220. If the state of the BFD switch is off, the network device does not need to create a BFD detection session, nor does it need to perform step S220.

[0110] In step S220, the network device uses the combination of the first BFD session attribute, the first segment list, and the first endpoint as a key to search the BFD session statistics table to see whether a corresponding BFD session already exists.

[0111] The combination of the first BFD session attribute, the first segment list and the first endpoint is equivalent to the query condition, and the network device will match the first BFD session attribute, the first segment list and the first endpoint with the table key1 in each record in the BFD session statistics table.

[0112] Taking the matching with the table key1 in the first record in the BFD session statistics table as an example, for example, the first record in the SRv6 policyBFD session statistics table includes a key field and a value field, the key field includes the second endpoint, the second segment list, and the second BFD session attribute, and the value field includes the BFD detection state of the first BFD session. The network device matches the first BFD session attribute with the second BFD session attribute in the first record, matches the first segment list with the second segment list in the first record, and matches the first endpoint with the second endpoint in the first record.

[0113] Step S230: If the first BFD session attribute, the first segment list, the first endpoint and the operation hit the first record in the BFD session statistics table, the network device does not need to create a BFD session, and the network device subscribes to the detection status of the BFD session in the first record hit in the BFD session statistics table for the first segment list.

[0114] A match with the operation means that the three parameters, namely, the BFD session attributes, segment list, and endpoint, match the BFD session attributes, segment list, and endpoint recorded in the BFD session statistics table. Since the SRv6 policy BFD session statistics table records the BFD sessions that have been created for each segmentlist under each candidate path under the SRv6 policy in the historical time period, if the input first segment list matches the second segment list in the first record in the BFD session statistics table, and the input first BFD session attribute matches the second BFD session attribute in the first record, and the input first endpoint matches the second endpoint in the first record, this situation is equivalent to satisfying the condition for multiplexing the BFD session, because a BFD session (first BFD session) that meets the condition has been created before, and the BFD detection state of the BFD session is saved through the first record. The created BFD session can be used to process the newly created segment list. Therefore, the network device does not need to create a new BFD session, and subscribes the BFD detection state of the historically created BFD session (first BFD session) for the first segment list (newly created segment list), thereby avoiding repeated creation of BFD sessions and causing waste of BFD session resources.

[0115] The matching method is, for example, a strict matching method. For example, if the input first segment list is the same as the second segment list in the first record in the BFD session statistics table, and the input first BFD session attribute is the same as the second BFD session attribute in the first record, and the input first endpoint is the same as the second endpoint in the first record, then the first segment list is subscribed to the detection status of the BFD session in the first record.

[0116] The first segment list and the second segment list are the same, for example, the SID of each position in the first segment list is the same as the SID of the corresponding position in the second segment list. In other words, the first segment list and the second segment list have the same SID and the arrangement order of the SID is the same.

[0117] The first BFD session attribute and the second BFD session attribute are, for example, the first BFD session attribute and the second BFD session attribute have the same BFD type (for example, both are single-arm BFD or both are SBFD), and have the same return entry segmentlist enable bit (for example, both enable the return entry segment list or both do not enable the return entry segment list), and have the same non-protection path enable bit (for example, both enable the BFD detection message return to pass through the protection path or both do not enable the BFD detection message to pass through the protection path), and have the same minimum sending interval, and have the same detection multiplier. In other words, when the parameters of each dimension in the two BFD session attributes are the same, it is confirmed that the two BFD session attributes match. For example, when the input BFD session attribute matches each field in the session attribute subtable in the BFD session statistics table, it is confirmed that the two BFD session attributes match.

[0118] Subscribing to the detection status of a BFD session is used to notify the segment list that uses the BFD session when the detection status of the BFD session changes, so that the status of the segment list that uses the BFD session can be updated accordingly with the latest status of the BFD session. An example of subscribing to the detection status of a BFD session for a first segment list is that the network device adds an identifier of the first segment list to a first record. For example, the first record includes a reference tree, and the network device adds an identifier of the first segment list to the reference tree. For another example, the first record includes a reference list, and the network device adds an identifier of the first segment list to the reference list.

[0119] Step S240: When the detection status of the BFD session is updated, the network device notifies the segment list corresponding to the segment list ID to update the status of the segment list based on the segment list ID stored in the SRv6 policy BFD session statistics table.

[0120] The detection state change of the BFD session includes the detection state of the BFD session being updated from up to down and the intermediate state of the BFD session being updated. In a possible implementation, when the detection state of the BFD session is updated, the network device traverses the identifier of each segment list in the reference tree or reference list in the first record, and notifies the segment list corresponding to each traversed segment list identifier that the detection state of the BFD session has been updated.

[0121] The status of the segment list is used to indicate the connectivity of the path corresponding to the segment list. In a possible implementation, if the detection status of the BFD session is updated from up to down, the network device updates the status of the segment list from up to down. If the detection status of the BFD session is updated from down to up, the network device updates the status of the segment list from down to up.

[0122] In a possible implementation, when the detection status of the BFD session in the first record of the SRv6 policy BFD session statistics table is updated, the network device traverses each segment list ID stored in the reference tree in the first record, and for each segment list ID traversed, the network device notifies the segmentlist corresponding to the segment list ID that the status of the segment list is updated. Alternatively, the network device traverses each segment list ID stored in the reference list in the first record, and for each segment list ID traversed, the network device notifies the segmentlist corresponding to the segmentlist ID that the status of the segment list is updated.

[0123] Step S250: If the first BFD session attribute, the first segment list, and the first endpoint do not hit the BFD session statistics table, the network device adds a new record to the BFD session statistics table, and the network device creates a BFD session based on the newly added record.

[0124] For any record in the BFD session statistics table, if any one or two of the three parameters of the first BFD session attribute, the first segmentlist and the first endpoint do not match the corresponding parameters in the record in the BFD session statistics table, it is determined that the record is not hit.

[0125] Step S260: The network device subscribes to the BFD status of the newly added record in the BFD session statistics table for the first segment list.

[0126] The network device can traverse each record in the BFD session statistics table. If the three parameters of the first BFD session attribute, the first segment list and the first endpoint do not hit any record in the BFD session statistics table, or in other words, the first BFD session attribute, the first segment list and the first endpoint do not completely match the BFD session attributes, segment list and endpoint in each record in the BFD session statistics table, the network device can determine that the first BFD session attribute, the first segment list and the first endpoint do not hit the BFD session statistics table.

[0127] For example, the BFD session statistics table includes a first record, and the first record includes a second BFD session attribute, a second segment list, and a second endpoint. If the first BFD session attribute does not match the second BFD session attribute, or the first segment list does not match the second segment list, or the first endpoint does not match the second endpoint, the network device determines that the first segment list, the first endpoint, and the first BFD session attribute do not match the first record.

[0128] The network device adds a new record to the BFD session statistics table to save the detection status of the newly created BFD session through the new record for use when querying the detection status of the BFD session next time.

[0129] In addition, when the detection status of the BFD session is updated after a new record is added, the network device adds a new record based on the SRv6 policyBFD session statistics table and notifies the relevant segment list that has subscribed to the record to update the status of the segment list. The relevant segment list is, for example, the segment list corresponding to the segmentlist ID stored in the reference tree or reference list.

[0130] In step S270, the user inputs a delete instruction for the first segment list under the candidate path in the SRv6 policy. In response to the delete instruction, the network device searches the SRv6 policy BFD session statistics table based on the identifier (session ID) of the first BFD session stored under the first segment list.

[0131] Step S280: If the identifier of the first BFD session matches the first record, the network device deletes the identifier of the first segment list from the first record.

[0132] Specifically, the network device matches the identifier of the first BFD session with the identifier of the BFD session in the first record. In response to the identifier of the first BFD session matching the identifier of the BFD session in the first record, the network device deletes the identifier of the first segment list from the reference tree or reference list of the first record, so that the length of the reference tree or reference list is reduced by one.

[0133] In step S290, when the length of the reference tree or reference list in the first record is 0, it indicates that no segment list uses the first BFD session, which is equivalent to a residual BFD session. The network device can delete the first record and delete the first BFD session, thereby avoiding BFD session leakage caused by the fact that there is no segment list referencing the first BFD session while the first BFD session is still running.

[0134] The method provided in this embodiment subscribes the detection status of the BFD session already recorded in the SRv6 policyBFD session statistics table for the segment list when the newly created segment list, the endpoint corresponding to the segment list, and the BFD session attributes to be enabled respectively match the segmentlist, the endpoint, and the BFD session attributes already recorded in the SRv6 policyBFD session statistics table. Therefore, there is no need to recreate the BFD session for the newly created segment list, but the detection status of the BFD session created historically (the detection status of the BFD session in the matching record in the SRv6 policyBFD session statistics table) can be reused, thereby greatly reducing the number of BFD sessions that need to be established and maintained.

[0135] Furthermore, since the number of BFD sessions that need to be established and maintained is reduced, the processing overhead caused by the CPU generating and sending probe messages for BFD sessions is greatly reduced, which reduces the burden on the CPU and saves timer resources occupied by BFD sessions. It can be seen that the system burden is reduced and competitiveness is enhanced in large-scale scenarios.

[0136] The above describes the implementation process in the SRv6 policy scenario with Example 1. Example 1 is applicable to IPv6 scenarios. The following describes the process of the SR-MPLS TE policy scenario with Example 2. Example 2 is applicable to IPv4 scenarios. The main difference between Example 2 and Example 1 is that each SID in the segment list in Example 2 is an MPLS label, while each SID in the segment list in Example 1 is an IPv6 address. The processing logic of Example 2 is similar to that of Example 1.

[0137] Example 2

[0138] Example 2 is an implementation example of a method for managing a BFD session in an SR-MPLS TE policy scenario. Example 1 involves the application of an SRv6 policy BFD session statistics table and an SRv6 policy BFD session attribute subtable.

[0139] The SR-MPLS TE policy BFD session statistics table is used to record the correspondence between the detection results of the BFD session used by each segmentlist in the SR-MPLS TE policy and the segment list that subscribes to the BFD session. Each record in the SR-MPLS TE policy BFD session statistics table includes a key (key or index) field and a value field. The key field includes table key1 and table key2.

[0140] Table key1 includes endpoint, segment list and BFD session attribute. A table key1 can uniquely index a record. Table key2 includes the session ID of the BFD session.

[0141] The value field includes the BFD detection state (BFD state) and the segment list ID. The segment list ID is used to identify the segment list subscribed to the BFD session. For the data structure carrying the segment list ID in the SRv6 policy BFD session statistics table, in one possible implementation, each record in the SR-MPLS TE policy BFD session statistics table includes a reference tree field, and the reference tree field is used to save the segment list ID subscribed to the corresponding record. In another possible implementation, each record in the SRv6 policy BFD session statistics table includes a reference list field, and the reference list field is used to save the segment list ID subscribed to the corresponding BFD session.

[0142] The session attribute subtable includes an SBFD enable bit, a one-arm BFD enable bit, a backhaul in-segment list enable bit, a non-protection path enable bit, a minimum transmission interval (eg, an SBFD min-tx-interval value), and a detection multiplier (eg, an SBFD detect-multiplier value).

[0143] In a possible implementation, the session ID in the SR-MPLS TE policy BFD session statistics table is stored in the segment list under the candidate path under the SR-MPLS TE policy.

[0144] The following describes the processing logic of managing SR-MPLS TE policy BFD sessions on network devices in combination with the above SR-MPLS TE policy. For more implementation details of steps 1 to 9, see the attached Figure 2 Description.

[0145] Step 1: The user inputs an instruction to create a first segment list under the candidate path under the SR-MPLS TE policy. The network device responds to the instruction to create the first segment list. The network device obtains the first BFD session attribute to be enabled for the first segment list, the first segment list, and the first endpoint corresponding to the first segment list.

[0146] In one possible implementation, the network device also obtains the status of the BFD switch corresponding to the SR-MPLS TE policy. The status of the BFD switch is used to indicate whether BFD is enabled. If the status of the BFD switch is on, the network device performs step 2. If the status of the BFD switch corresponding to the SR-MPLS TE policy is off, the network device does not need to create a BFD detection session and does not need to perform step 2.

[0147] In step 2, the network device uses the combination of the first BFD session attribute, the first segment list, and the first endpoint as a key to search in the BFD session statistics table whether a corresponding BFD session already exists.

[0148] Step three: If the first BFD session attribute, the first segment list, the first endpoint and the operation hit the first record in the BFD session statistics table, the network device does not need to create a BFD session, and the network device subscribes to the detection status of the BFD session in the first record hit in the BFD session statistics table for the first segment list.

[0149] Step 4: When the detection status of the BFD session is updated, the network device notifies the segment list corresponding to the segment list ID to update the status of the segment list based on the segment list ID stored in the reference tree or reference list in the SR-MPLS TE policy BFD session statistics table.

[0150] Step 5: If the first BFD session attribute, the first segment list, and the first endpoint do not hit the BFD session statistics table, the network device adds a new record to the BFD session statistics table, the network device creates a BFD session based on the newly added record, and then the network device subscribes to the BFD status of the record in the BFD session statistics table.

[0151] Step 6: When the detection status of the BFD session is updated, the network device notifies the segment list that has subscribed to the record to update the status of the segment list based on the SR-MPLS TE policy BFD session statistics table.

[0152] Step 7: When the network device deletes the first segment list under the candidate path in the SR-MPLS TE policy, the network device searches the SR-MPLS TE policy BFD session statistics table based on the identifier of the BFD session stored under the first segment list.

[0153] Step 8: If the identifier of the BFD session matches the first record in the SR-MPLS TE policy BFD session statistics table, the network device deletes the identifier of the segment list from the first record.

[0154] Specifically, the network device matches the identifier of the first BFD session with the identifier of the BFD session in the first record. In response to the identifier of the first BFD session matching the identifier of the BFD session in the first record, the network device deletes the identifier of the first segment list from the reference tree or reference list of the first record, so that the length of the reference tree or reference list is reduced by one.

[0155] Step nine, when the length of the reference tree or the reference list is 0, indicating that no BFD session references the first record, the network device can delete the first record and simultaneously delete the corresponding first BFD session, thereby avoiding BFD session leakage caused by the BFD session still running without the segment list referencing the BFD session.

[0156] Example 3

[0157] Instance 3 is an implementation example of the BFD session management method in the SRv6 policy scenario. The main difference between Instance 3 and Instance 1 is that the SRv6 policy BFD session statistics table in Instance 1 stores the segment list ID subscribed to the BFD session, while the SRv6 policy BFD session statistics table in Instance 3 stores the address pointer of the segment list subscribed to the BFD session, and the address pointer of the segment list points to the segment list. The address pointer of the segment list is used to access and operate the segment list.

[0158] Example 3 involves the definition of the SRv6 policy BFD session statistics table.

[0159] The SRv6 policy BFD session statistics table is used to record the correspondence between the detection results of the BFD session used by each segment list in the SRv6 policy and the segment list that subscribes to the BFD session. Each record in the SRv6 policy BFD session statistics table includes a key (key or index) field and a value field. The key field includes table key1 and table key2. Table key1 includes endpoint, segment list, and BFD session attribute (session attribute). Network devices can uniquely index a record in the SRv6 policy BFD session statistics table based on table key1. Table key2 includes the session identifier (session ID) of the BFD session. Network devices can uniquely index a record in the SRv6 policy BFD session statistics table based on the session ID. Table key1 and table key2 can be used either one. The value field in each record in the SRv6 policy BFD session statistics table includes the BFD detection state (BFD state) and the address pointer of the segment list.

[0160] For example, each record in the SRv6 policy BFD session statistics table includes a reference tree field or a reference list field, and the reference tree field or the reference list field is used to store an address pointer of a segment list subscribed to the corresponding record.

[0161] The session attribute subtable includes an SBFD enable bit, a one-arm BFD enable bit, a backhaul in-segment list enable bit, a non-protection path enable bit, a minimum transmission interval (eg, an SBFD min-tx-interval value), and a detection multiplier (eg, an SBFD detect-multiplier value).

[0162] In a possible implementation, the address pointer of the record corresponding to the segment list in the BFD session statistics table is stored in the segment list under the candidate path under the SRv6 policy.

[0163] The following describes the processing logic of managing SRv6 policyBFD sessions on network devices in combination with the SRv6 policy BFD session statistics table defined above. For more implementation details of steps 1 to 9, see the attached Figure 2 Description.

[0164] Step 1: The user inputs an instruction to create a first segment list under the candidate path under the SRv6 policy. The network device responds to the instruction to create the first segment list. The network device obtains the first segment list, the first BFD session attribute to be enabled for the first segment list, and the first endpoint corresponding to the first segment list.

[0165] In a possible implementation, the network device also obtains the status of the BFD switch corresponding to the SRv6 policy. The status of the BFD switch is used to indicate whether BFD is enabled. If the status of the BFD switch is on, the network device performs step 2. If the status of the BFD switch corresponding to the SRv6 policy is off, the network device does not need to create a BFD detection session and does not need to perform step 2.

[0166] Step 2: If the network device uses the combination of the first BFD session attribute, the first segment list, and the first endpoint as a key, it searches the SRv6 policy BFD session statistics table to see whether a corresponding BFD session already exists.

[0167] Step three: If the first BFD session attribute, the first segment list, the first endpoint and the operation hit the first record in the SRv6 policy BFD session statistics table, the network device does not need to create a BFD session, and the network device subscribes to the detection status of the BFD session in the first record hit in the BFD session statistics table for the first segment list.

[0168] Step 4: When the detection status of the BFD session is updated, the network device notifies the segment list pointed to by the address pointer of the segment list to update the status of the segment list based on the address pointer of the segment list stored in the reference tree or reference list in the SRv6 policy BFD session statistics table.

[0169] Step 5: If the first BFD session attribute, the first segment list, and the first endpoint do not hit the SRv6policy BFD session statistics table, the network device adds a new record to the SRv6 policy BFD session statistics table, creates a BFD session based on the newly added record, and then subscribes to the detection status of the BFD session of the record in the BFD session statistics table.

[0170] Step 6: When the detection status of the BFD session changes, the network device notifies the segmentlist address pointer that has subscribed to the record to update the status of the segment list.

[0171] Step 7: When the network device deletes the first segment list under the candidate path in an SRv6 policy, the network device searches the BFD session statistics table based on the address pointer of the record in the BFD session statistics table stored under the first segment list.

[0172] The address pointer of the record in the BFD session statistics table points to a specific record in the BFD session statistics table, specifically the record where the address pointer of the segment list is located. The reference tree or reference list of the record stores the address pointer of the segment list, which is equivalent to forming a mutual pointer. The network device can search for the corresponding record in the BFD session statistics table based on the address pointer of the record in the BFD session statistics table.

[0173] Step eight: If the address pointer of the record in the BFD session statistics table points to the first record, the network device deletes the address pointer of the first segment list from the reference tree or reference list of the first record.

[0174] Step nine: When the length of the reference tree or the reference list is 0, the network device deletes the first record and simultaneously deletes the BFD session corresponding to the first record.

[0175] The method provided in this embodiment subscribes the detection status of the BFD session already recorded in the SRv6 policyBFD session statistics table for the segment list when the newly created segment list, the endpoint corresponding to the segment list, and the BFD session attributes to be enabled match the segmentlist, the endpoint, and the BFD session attributes already recorded in the SRv6 policyBFD session statistics table, respectively. Therefore, there is no need to recreate the BFD session for the newly created segment list, but the detection status of the BFD session created historically (the detection status of the BFD session in the matching record in the SRv6 policyBFD session statistics table) can be reused. Therefore, the number of BFD sessions that need to be established is greatly reduced, BFD session resources are saved, the system burden is reduced, and the competitiveness in large-scale scenarios is enhanced.

[0176] Example 4

[0177] Instance 4 is an implementation example of the method for managing BFD sessions in the SR-MPLS TE policy scenario. The main difference between Instance 4 and Instance 2 is that the SR-MPLS TE policy BFD session statistics table in Instance 2 stores the segment list ID subscribed to the BFD session, while the SR-MPLS TE policy BFD session statistics table in Instance 4 stores the address pointer of the segment list subscribed to the BFD session, and the address pointer of the segment list points to the segment list. The address pointer of the segment list is used to access and operate the segment list.

[0178] Example 4 involves the definition of the SR-MPLS TE policy BFD session statistics table.

[0179] The SR-MPLS TE policy BFD session statistics table is used to record the correspondence between the detection results of the BFD session used by each segmentlist in the SR-MPLS TE policy and the segment list subscribed to the BFD session. Each record in the SR-MPLS TE policy BFD session statistics table includes a key (key or index) field and a value field. The key field includes table key1 and table key2.

[0180] Table key1 includes endpoint, segment list, and BFD session attribute. The network device can uniquely index a record in the SR-MPLS TE policy BFD session statistics table based on table key1.

[0181] Table key2 includes the session identifier (session ID) of the BFD session. The network device can uniquely index a record in the SR-MPLS TE policy BFD session statistics table based on the session ID. Table key1 and table key2 can be used either one. The value field in each record in the SR-MPLS TE policy BFD session statistics table includes the BFD detection state (BFDstate) and the address pointer of the segment list. For example, each record in the SRv6 policy BFD session statistics table includes a reference tree field or a reference list field, and the reference tree field or the reference list field is used to store the address pointer of the segment list that subscribes to the corresponding record.

[0182] The session attribute subtable includes an SBFD enable bit, a one-arm BFD enable bit, a backhaul in-segment list enable bit, a non-protection path enable bit, a minimum transmission interval (eg, an SBFD min-tx-interval value), and a detection multiplier (eg, an SBFD detect-multiplier value).

[0183] Address pointer of the records in the BFD session statistics table stored in the segment list under the candidate path under the SR-MPLS TE policy.

[0184] The following describes the processing logic of managing SR-MPLS TE policy BFD sessions on network devices in combination with the SR-MPLS TE policy BFD session statistics table defined above. Figure 2 Description.

[0185] Step 1: The user inputs an instruction to create the first segmentlist under the candidate path under the SR-MPLS TE policy. The network device responds to the instruction to create the first segmentlist. The network device obtains the first segmentlist, the first BFD session attribute to be enabled for the first segmentlist, and the first endpoint corresponding to the first segmentlist.

[0186] In one possible implementation, the network device also obtains the status of the BFD switch corresponding to the SR-MPLS TE policy. The status of the BFD switch is used to indicate whether BFD is enabled. If the status of the BFD switch is on, the network device performs step 2. If the status of the BFD switch corresponding to the SR-MPLS TE policy is off, the network device does not need to create a BFD detection session and does not need to perform step 2.

[0187] In step 2, the network device uses the combination of the first BFD session attribute, the first segment list, and the first endpoint as a key to search the SR-MPLS TE policy BFD session statistics table to see whether a corresponding BFD session already exists.

[0188] In step three, if the first BFD session attribute, the first segment list, the first endpoint and the operation hit the first record in the SR-MPLS TE policy BFD session statistics table, the network device does not need to create a BFD session, and the network device subscribes to the detection status of the BFD session in the first record hit in the SR-MPLS TE policy BFD session statistics table for the first segment list.

[0189] Step 4: When the detection status of the BFD session is updated, the network device notifies the segment list pointed to by the address pointer of the segment list to update the status of the segment list based on the address pointer of the segment list stored in the reference tree or reference list in the SR-MPLS TE policy BFD session statistics table.

[0190] In step 5, if the first BFD session attribute, the first segment list, and the first endpoint do not hit the SR-MPLS TE policy BFD session statistics table, the network device adds a new record to the BFD session statistics table, creates a BFD session based on the newly added record, and then subscribes to the BFD detection status of the record in the BFD session statistics table.

[0191] Step 6: When the detection status of the BFD session changes, the network device notifies the segmentlist address pointer that has subscribed to the record to update the status of the segment list.

[0192] Step 7: When the network device deletes the first segment list under the candidate path in an SR-MPLS TE policy, the network device searches the BFD session statistics table based on the address pointer of the record in the BFD session statistics table stored under the first segment list.

[0193] Step eight: If the address pointer of the record in the BFD session statistics table points to the first record, the network device deletes the address pointer of the first segment list from the reference tree or reference list of the first record.

[0194] Step nine: When the length of the reference tree or the reference list is 0, the network device deletes the first record and simultaneously deletes the BFD session corresponding to the first record.

[0195] Figure 3 1 is a schematic diagram of a structure of a BFD session management device 300 provided in an embodiment of the present application, wherein the device 300 includes:

[0196] an acquiring unit 310, configured to acquire, in response to a creation instruction for a first segment list segment list, the first segment list, a first endpoint endpoint, and a first BFD session attribute, wherein the first endpoint is a destination address of the first segment list, and the first BFD session attribute is a BFD session attribute to be enabled for the first segment list;

[0197] The processing unit 320 is used to search the segment routing policy SR policy BFD session statistics table based on the first segment list, the first endpoint and the first BFD session attributes, wherein the SR policy BFD session statistics table includes a first record, and the first record includes a second segment list, a second endpoint, a second BFD session attribute and a detection status of the first BFD session; in response to the first segment list matching the second segment list, the first endpoint matching the second endpoint and the first BFD session attribute matching the second BFD session attribute, subscribe to the detection status of the first BFD session for the first segment list.

[0198] In a possible implementation, the first record includes an identifier of the first BFD session and a first field, and the processing unit 320 is used to add the identifier of the first segment list to the first field in the first record; and store the identifier of the first BFD session under the first segment list.

[0199] In a possible implementation, the processing unit 320 is further used to obtain the identifier of the first segment list from the first record in response to an update of the detection status of the BFD session; and update the status of the first segment list based on the updated detection status of the BFD session and the identifier of the first segment list.

[0200] In a possible implementation, the processing unit 320 is further used to obtain the identifier of the first BFD session stored under the segment list in response to a delete instruction for the first segmentlist; search the SR policy BFD session statistics table based on the identifier of the first BFD session; and delete the identifier of the first segment list from the first field in the first record in response to the identifier of the first BFD session hitting the first record.

[0201] In a possible implementation, the first record includes an identifier of the first BFD session and a first field, and the processing unit 320 is used to add an address pointer of the first segment list to the first field in the first record; and store the address pointer of the first record under the first segment list.

[0202] In a possible implementation, the processing unit 320 is further used to obtain the address pointer of the first segment list from the first record in response to an update of the detection status of the BFD session; and update the status of the first segment list based on the updated detection status of the BFD session and the address pointer of the first segment list.

[0203] In a possible implementation, the processing unit 320 is further used to obtain the address pointer of the first record stored under the segment list in response to a delete instruction for the first segmentlist; search the SR policy BFD session statistics table based on the address pointer of the first record; and in response to the address pointer of the first record pointing to the first record in the SR policy BFD session statistics table, delete the address pointer of the first segment list from the first field in the first record.

[0204] In one possible implementation, the processing unit 320 is further used to create a second BFD session and subscribe to the detection status of the second BFD session for the first segment list in response to the first segmentlist, the first endpoint, and the first BFD session attributes not fully matching the segment list, endpoint, and BFD session attributes in each record in the SR policy BFD session statistics table.

[0205] In a possible implementation manner, the processing unit 320 is further configured to delete the first record and the session identifier of the first BFD session in response to the length of the first field being zero.

[0206] In a possible implementation manner, the device is arranged at a head node of a forwarding path indicated by the first segment list.

[0207] In a possible implementation, the first BFD session attribute includes a first SBFD enable bit, a first single-arm BFD enable bit, a first backhaul in-segment list enable bit, a first non-protected path enable bit, a first minimum sending interval, and a first detection multiplier; the second BFD session attribute includes a second SBFD enable bit, a second single-arm BFD enable bit, a second backhaul in-segment list enable bit, a second non-protected path enable bit, a second minimum sending interval, and a second detection multiplier; in response to the first segment list matching the second segment list, the first endpoint matching the second endpoint, and the first BFD session attribute matching the second BFD session attribute, the processing unit 320 is further configured to, in response to the first segment list being the same as the second segment list, the first endpoint being the same as the second endpoint, the first SBFD enable bit being the same as the second SBFD enable bit, the first single-arm BFD enable bit being the same as the second single-arm BFD enable bit, the first backhaul in-segment list enable bit being the same as the second backhaul in-segment list enable bit. The first segment list enable bit is the same, the first non-protected path enable bit is the same as the second non-protected path enable bit, the first minimum sending interval is the same as the second minimum sending interval, and the first detection multiplier is the same as the second detection multiplier, subscribing the first segment list to the detection status of the first BFD session.

[0208] Figure 3 The device embodiments described are merely illustrative. For example, the division of the above units is only a logical functional division. There may be other division methods in actual implementation, such as multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. The functional units in the various embodiments of the present application may be integrated into a processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0209] Each unit in the BFD session management device 300 is implemented entirely or partially by software, hardware, firmware, or any combination thereof.

[0210] In conjunction with the network device 400 described below, some possible implementations of various functional units in the management apparatus 300 for implementing a BFD session using hardware or software are described below.

[0211] In the case of software implementation, for example, the acquisition unit 310 and the processing unit 320 are composed of Figure 4At least one processor 401 in the processor 401 reads the program code stored in the memory 402 and generates a software function unit to implement it.

[0212] Figure 3 The above-mentioned units are implemented by different hardware in the network device, for example, the acquisition unit 310 is implemented by Figure 4 The processing unit 320 is implemented by a part of the processing resources of at least one processor 401 in the multi-core processor (for example, one core or two cores in the multi-core processor), and the processing unit 320 is implemented by Figure 4 The remaining processing resources of at least one processor 401 (such as other cores in a multi-core processor) may be completed by using a field-programmable gate array (FPGA) or a coprocessor or other programmable device. Figure 4 The network interface 403 is implemented in.

[0213] Figure 4 It is a structural diagram of a network device 400 provided in an embodiment of the present application.

[0214] Optionally, in combination with Figure 1 Come and see, Figure 4 The network device 400 shown is Figure 1 Optionally, in combination with Figure 2 According to the method shown, Figure 4 The network device 400 is shown to be used to perform Figure 2 The method flow is shown.

[0215] The network device 400 includes at least one processor 401 , a memory 402 , and at least one network interface 403 .

[0216] The processor 401 is, for example, a general-purpose central processing unit (CPU), a network processor (NP), a graphics processing unit (GPU), a neural-network processing unit (NPU), a data processing unit (DPU), a microprocessor, or one or more integrated circuits for implementing the solution of the present application. For example, the processor 401 includes an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD is, for example, a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0217] The memory 402 is, for example, a read-only memory (ROM) or other static storage device that can store static information and instructions, a random access memory (RAM) or other dynamic storage device that can store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. Optionally, the memory 402 exists independently and is connected to the processor 401 through the internal connection 404. Alternatively, the memory 402 and the processor 401 are optionally integrated together.

[0218] The network interface 403 uses any transceiver-like device for communicating with other devices or communication networks. The network interface 403 includes, for example, at least one of a wired network interface or a wireless network interface. The wired network interface is, for example, an Ethernet interface. The Ethernet interface is, for example, an optical interface, an electrical interface, or a combination thereof. The wireless network interface is, for example, a wireless local area network (WLAN) interface, a cellular network interface, or a combination thereof.

[0219] In some embodiments, the processor 401 includes one or more CPUs, such as Figure 4 CPU0 and CPU1 are shown in the figure.

[0220] In some embodiments, the network device 400 optionally includes multiple processors, such as Figure 4 401 and processor 405 are shown in FIG. Each of these processors is, for example, a single-CPU, or a multi-CPU. The processor herein optionally refers to one or more devices, circuits, and / or processing cores for processing data (such as computer program instructions).

[0221] In some embodiments, the network device 400 further includes an internal connection 404. The processor 401, the memory 402, and the at least one network interface 403 are connected via the internal connection 404. The internal connection 404 includes a path to transmit information between the above components. Optionally, the internal connection 404 is a single board or a bus. Optionally, the internal connection 404 is divided into an address bus, a data bus, a control bus, etc.

[0222] In some embodiments, the network device 400 further includes an input / output interface 406. The input / output interface 406 is connected to the internal connection 404.

[0223] Optionally, the processor 401 implements the method in the above embodiment by reading the program code stored in the memory 402, or the processor 401 implements the method in the above embodiment by the program code stored internally. In the case where the processor 401 implements the method in the above embodiment by reading the program code stored in the memory 402, the memory 402 stores the program code 410 that implements the method provided in the embodiment of the present application.

[0224] For more details on how the processor 401 implements the above functions, please refer to the descriptions in the previous method embodiments, which will not be repeated here.

[0225] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0226] A refers to B, which means that A is the same as B or A is a simple variant of B.

[0227] The terms "first" and "second" in the description and claims of the embodiments of the present application are used to distinguish different objects, rather than to describe the specific order of objects, and cannot be understood as indicating or implying relative importance. For example, the first segment list and the second segment list are used to distinguish different segment lists, rather than to describe the specific order of segment lists, and cannot be understood as the first segment list being more important than the second segment list.

[0228] In the embodiments of the present application, unless otherwise specified, "at least one" means one or more, and "a plurality of" means two or more. For example, a plurality of segment lists means two or more segment lists.

[0229] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of 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, the process or function described in accordance with the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk SolidState Disk (SSD)), etc.

[0230] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for managing a bidirectional forwarding detection (BFD) session, characterized in that: The method comprises: In response to a creation instruction for a first segment list segment list, the network device obtains the first segment list, a first endpoint endpoint, and a first BFD session attribute, wherein the first endpoint is a destination address of the first segment list, and the first BFD session attribute is a BFD session attribute to be enabled for the first segment list; The network device searches a segment routing policy SR policy BFD session statistics table based on the first segment list, the first endpoint, and the first BFD session attribute, wherein the SR policy BFD session statistics table includes a first record, and the first record includes a second segment list, a second endpoint, a second BFD session attribute, and a detection status of the first BFD session; In response to the first segment list matching the second segment list, the first endpoint matching the second endpoint, and the first BFD session attribute matching the second BFD session attribute, the network device subscribes to the detection status of the first BFD session for the first segment list.

2. The method according to claim 1, characterized in that The first record includes an identifier of the first BFD session and a first field, and the network device subscribes to a detection status of the BFD session for the first segmentlist, including: The network device adds the identifier of the first segmentlist to the first field in the first record; The network device stores the identifier of the first BFD session under the first segmentlist.

3. The method according to claim 2, characterized in that The method further comprises: In response to an update of the detection state of the BFD session, the network device obtains an identifier of the first segment list from the first record; The network device updates the state of the first segment list based on the updated detection state of the BFD session and the identifier of the first segment list.

4. The method according to claim 2 or 3, characterized in that: The method further comprises: In response to the deletion instruction of the first segment list, the network device obtains the identifier of the first BFD session stored in the segment list; The network device searches the SR policy BFD session statistics table based on the identifier of the first BFD session; In response to the identifier of the first BFD session hitting the first record, the network device deletes the identifier of the first segmentlist from the first field in the first record.

5. The method according to claim 1, characterized in that The first record includes an identifier of the first BFD session and a first field, and the network device subscribes to a detection status of the BFD session for the first segmentlist, including: The network device adds the address pointer of the first segmentlist to the first field in the first record; The network device stores the address pointer of the first record under the first segmentlist.

6. The method according to claim 5, characterized in that The method further comprises: In response to an update of the detection state of the BFD session, the network device obtains an address pointer of the first segment list from the first record; The network device updates the state of the first segment list based on the updated detection state of the BFD session and the address pointer of the first segment list.

7. The method according to claim 5 or 6, characterized in that: The method further comprises: In response to a delete instruction for the first segment list, the network device obtains an address pointer of the first record stored in the segment list; The network device searches the SR policy BFD session statistics table based on the address pointer of the first record; In response to the address pointer of the first record pointing to the first record in the SR policy BFD session statistics table, the network device deletes the address pointer of the first segmentlist from the first field in the first record.

8. The method according to claim 1, characterized in that The method further comprises: In response to the fact that the first segment list, the first endpoint and the first BFD session attributes do not completely match the segment list, endpoint and BFD session attributes in each record in the SR policy BFD session statistics table, the network device creates a second BFD session and subscribes to the detection status of the second BFD session for the first segmentlist.

9. The method according to claim 4 or 7, characterized in that: The method further comprises: In response to the length of the first field being zero, the network device deletes the first record and deletes the session identifier of the first BFD session.

10. The method according to any one of claims 1 to 9, characterized in that The network device is the head node of the forwarding path indicated by the first segment list.

11. The method according to any one of claims 1 to 10, characterized in that The first BFD session attribute includes a first SBFD enable bit, a first single-arm BFD enable bit, a first backhaul in-segment list enable bit, a first non-protected path enable bit, a first minimum sending interval, and a first detection multiplier; the second BFD session attribute includes a second SBFD enable bit, a second single-arm BFD enable bit, a second backhaul in-segment list enable bit, a second non-protected path enable bit, a second minimum sending interval, and a second detection multiplier; in response to the first segment list matching the second segment list, the first endpoint matching the second endpoint, and the first BFD session attribute matching the second BFD session attribute, the network device subscribing to the detection state of the first BFD session for the first segment list, including: In response to the first segment list being the same as the second segment list, the first endpoint being the same as the second endpoint, the first SBFD enable bit being the same as the second SBFD enable bit, the first single-arm BFD enable bit being the same as the second single-arm BFD enable bit, the first backhaul in-segment list enable bit being the same as the second backhaul in-segment list enable bit, the first non-protected path enable bit being the same as the second non-protected path enable bit, the first minimum sending interval being the same as the second minimum sending interval, and the first detection multiplier being the same as the second detection multiplier, the network device subscribes to the detection status of the first BFD session for the first segment list.

12. A management device for a bidirectional forwarding detection (BFD) session, characterized in that: The device comprises: an acquiring unit, configured to acquire, in response to a creation instruction for a first segment list segment list, the first segment list, a first endpoint endpoint, and a first BFD session attribute, wherein the first endpoint is a destination address of the first segment list, and the first BFD session attribute is a BFD session attribute to be enabled for the first segment list; A processing unit, configured to search a segment routing policy SR policy BFD session statistics table based on the first segment list, the first endpoint, and the first BFD session attributes, wherein the SR policy BFD session statistics table includes a first record, wherein the first record includes a second segment list, a second endpoint, a second BFD session attribute, and a detection status of the first BFD session; in response to the first segment list matching the second segment list, the first endpoint matching the second endpoint, and the first BFD session attribute matching the second BFD session attribute, subscribing the detection status of the first BFD session for the first segment list.

13. A network device, characterized in that: The network device comprises: a processor, the processor is coupled to a memory, the memory stores at least one computer program instruction, and the at least one computer program instruction is loaded and executed by the processor so that the network device implements the method described in any one of claims 1-11.

14. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction, and when the instruction is executed on a computer, the computer executes the method according to any one of claims 1 to 11.

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