Path establishment method and apparatus, node, and computer-readable storage medium

Abstract

The application provides a path establishment method and device, node and computer readable storage medium. The path establishment method comprises: obtaining routing information from a first IGP domain, wherein the routing information comprises first algorithm information and first target prefix information corresponding to the first algorithm information; and notifying the second border node of the routing information through a first BGP message, so that the second border node establishes a shortest forwarding path corresponding to the first algorithm information to the first target prefix according to the first algorithm information and the first target prefix information in the routing information. According to the scheme of the embodiment of the application, the algorithm information and the target prefix information corresponding to the algorithm information are notified to the second border node through the BGP message, so that the second border node can establish a shortest forwarding path based on the algorithm information across domains according to the algorithm information and the target prefix information, thereby filling the technical gap of the algorithm-related cross-domain path creation in the related art.

Description

Technical Field

[0001] The embodiments of the present invention relate to, but are not limited to, the field of communication technology, and particularly to a path establishment method and apparatus, node, and computer-readable storage medium thereof. Background Technology

[0002] Among current related technologies, the standard draft-ietf-lsr-flex-algo-13 (IGP Flex-algo for short) proposes a method that allows network elements within an IGP (Interior Gateway Protocol) domain to compute constraint-based paths in a network. Furthermore, it specifies a method for guiding packets along constraint-based paths using the Prefix SID of SR-MPLS (Segment Routing MPLS) and the Locator of SRv6 (Segment Routing IPv6). The standard draft-bonica-lsr-ip-flexalgo-01 proposes a method for applying IGP Flex-algo technology to pure IP networks without deployed segmentation routing, enabling the computation of flexible algorithm paths to ordinary IPv4 or IPv6 addresses. In the standard RFC8402 (which deals with segmented routing architecture), a shortest path calculation algorithm based on Strict-SPF (Strict Shortest Path First) is defined, which ensures that packets are forwarded strictly according to the calculated shortest path, and the shortest forwarding path is not modified by the local policies of each node.

[0003] However, the aforementioned algorithm-based shortest path calculation scheme is only applicable within the IGP domain and cannot support cross-domain scenarios, especially cross-AS (Autonomous System) scenarios. In other words, current related technologies cannot support cross-domain algorithm-based shortest path forwarding. Summary of the Invention

[0004] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0005] This invention provides a path establishment method, apparatus, node, and computer-readable storage medium that can establish a cross-domain algorithm-based shortest forwarding path.

[0006] In a first aspect, embodiments of the present invention provide a path establishment method applied to a first boundary node of a first IGP domain, wherein the first boundary node is connected to a second boundary node of a second IGP domain, the method comprising:

[0007] Obtain routing information from the first IGP domain, wherein the routing information includes first algorithm information and first target prefix information corresponding to the first algorithm information;

[0008] The routing information is announced to the second border node via a first BGP message, so that the second border node establishes the shortest forwarding path to the first target prefix corresponding to the first algorithm information based on the first algorithm information and the first target prefix information in the routing information.

[0009] Secondly, embodiments of the present invention also provide a path establishment apparatus, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the path establishment method described in the first aspect above.

[0010] Thirdly, embodiments of the present invention also provide a node, including the path establishment device described in the second aspect above.

[0011] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions for performing the path establishment method described above.

[0012] This invention includes: acquiring routing information from a first IGP domain, wherein the routing information includes first algorithm information and first target prefix information corresponding to the first algorithm information; and announcing the routing information to a second boundary node via a first BGP message, enabling the second boundary node to establish the shortest forwarding path to the first target prefix corresponding to the first algorithm information based on the first algorithm information and the first target prefix information in the routing information. According to the scheme provided by this invention, when a first boundary node of a first IGP domain acquires routing information including first algorithm information and first target prefix information corresponding to the first algorithm information, it announces the first algorithm information and the first target prefix information to a second boundary node of a second IGP domain via a first BGP message, enabling the first target prefix information corresponding to the first algorithm information from the first IGP domain to be announced to a second IGP domain different from the first IGP domain. This allows the second boundary node to establish the shortest forwarding path to the first target prefix in the first IGP domain based on the first algorithm information and the first target prefix information, and the shortest forwarding path corresponds to the first algorithm information. Therefore, the solution provided by the embodiments of the present invention can realize the establishment of cross-domain algorithm-based shortest forwarding paths, thereby filling the technical gap in the creation of cross-domain paths related to algorithms in related technologies.

[0013] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0014] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0015] Figure 1 This is a schematic diagram of a network topology for performing a path establishment method according to an embodiment of the present invention;

[0016] Figure 2 This is a flowchart of a path establishment method provided in one embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the field structure of the newly added algorithm extension field provided in one embodiment of the present invention;

[0018] Figure 4 This is a flowchart of a path establishment method provided in another embodiment of the present invention;

[0019] Figure 5This is a flowchart of a path establishment method provided in another embodiment of the present invention;

[0020] Figure 6 This is a flowchart of a path establishment method provided in another embodiment of the present invention;

[0021] Figure 7 This is a flowchart of a path establishment method provided in another embodiment of the present invention;

[0022] Figure 8 This is a flowchart of a path establishment method provided in another embodiment of the present invention;

[0023] Figure 9 This is a schematic diagram of a path establishment device provided in one embodiment of the present invention;

[0024] Figure 10 This is a schematic diagram of a node provided in one embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] It should be noted that although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0027] This invention provides a path establishment method, apparatus, node, and computer-readable storage medium. When a first boundary node in a first IGP domain obtains routing information including first algorithm information and first target prefix information corresponding to the first algorithm information, it announces the first algorithm information and the first target prefix information to a second boundary node in a second IGP domain via a first BGP message. This allows the first target prefix information corresponding to the first algorithm information from the first IGP domain to be announced to a second IGP domain different from the first IGP domain. As a result, the second boundary node can establish the shortest forwarding path to the first target prefix in the first IGP domain corresponding to the first algorithm information based on the first algorithm information and the first target prefix information. This achieves the establishment of a cross-domain algorithm-based shortest forwarding path, filling the technical gap in algorithm-related cross-domain path creation in related technologies.

[0028] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0029] like Figure 1 As shown, Figure 1 This is a schematic diagram of a network topology for performing a path establishment method according to an embodiment of the present invention. Figure 1 In the example, the network topology includes a first node 110, a second node 120, a third node 130, a fourth node 140, a fifth node 150, a sixth node 160, a seventh node 170, and an eighth node 180. Nodes 110, 120, 130, and 140 belong to the first IGP domain, while nodes 150, 160, 170, and 180 belong to the second IGP domain. Node 140 is the first boundary node in the first IGP domain, and node 150 is the second boundary node in the second IGP domain. Nodes 140 and 150 have established a Border Gateway Protocol (BGP) neighbor relationship.

[0030] The second node 120 and the fourth node 140 are connected; the fifth node 150 and the seventh node 170 are connected; the first node 110, the second node 120, the third node 130, and the fourth node 140 are connected end-to-end; and the fifth node 150, the sixth node 160, the seventh node 170, and the eighth node 180 are connected end-to-end. In the first IGP domain, the first node 110, the second node 120, and the fourth node 140 belong to the first flexible algorithm plane; the second node 120, the third node 130, and the fourth node 140 belong to the second flexible algorithm plane. In the second IGP domain, the fifth node 150, the sixth node 160, and the seventh node 170 belong to the third flexible algorithm plane; and the fifth node 150, the seventh node 170, and the eighth node 180 belong to the fourth flexible algorithm plane. The first and third flexible algorithm planes can have the same algorithm information, such as... Figure 1 As shown, both the first and third flexible algorithm planes are Flex-algo 128; while the second and fourth flexible algorithm planes can also have the same algorithm information, such as... Figure 1 As shown, both the second and fourth flexible algorithm planes are Flex-algo 129.

[0031] The first node 110, the second node 120, the third node 130, the fourth node 140, the fifth node 150, the sixth node 160, the seventh node 170, and the eighth node 180 can all be network devices such as routers or switches, capable of forwarding packets.

[0032] In such Figure 1In the network topology shown, the fourth node 140 and the fifth node 150 can send BGP messages to each other, so that the target prefix information from the first IGP domain can be advertised to the second IGP domain through BGP messages, so that the nodes in the second IGP domain can establish the shortest forwarding path to the first IGP domain based on the target prefix information, or so that the target prefix information from the second IGP domain can be advertised to the first IGP domain through BGP messages, so that the nodes in the first IGP domain can establish the shortest forwarding path to the second IGP domain based on the target prefix information.

[0033] The network topologies and application scenarios described in the embodiments of this invention are intended to more clearly illustrate the technical solutions of the embodiments of this invention, and do not constitute a limitation on the technical solutions provided in the embodiments of this invention. As those skilled in the art will know, with the evolution of network topologies and the emergence of new application scenarios, the technical solutions provided in the embodiments of this invention are also applicable to similar technical problems.

[0034] It will be understood by those skilled in the art that Figure 1 The topology shown does not constitute a limitation on the embodiments of the present invention and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0035] Based on the above network topology, various embodiments of the path establishment method of the present invention are proposed.

[0036] like Figure 2 As shown, Figure 2 This is a flowchart of a path establishment method provided in one embodiment of the present invention. This path establishment method can be applied to the first boundary node of a first IGP domain, for example... Figure 1 The fourth node 140 in the network topology shown. The path establishment method includes, but is not limited to, steps S101 and S102.

[0037] Step S101: Obtain routing information from the first IGP domain, wherein the routing information includes first algorithm information and first target prefix information corresponding to the first algorithm information.

[0038] It should be noted that the first algorithm information is the algorithm information defined in IGP Flex-algo. The first algorithm information is used to distinguish virtual topologies created by IGP Flex-algo. Virtual topologies with the same algorithm information can be classified as the same virtual topology, and different virtual topologies have different algorithm information.

[0039] In this step, obtaining routing information from the first IGP domain can be implemented in different ways, and this embodiment does not impose a specific limitation on it. For example, the routing information from the first IGP domain can be routing information sent by other nodes in the first IGP domain, such as... Figure 1 The routing information sent by the first node 110, the second node 120, or the third node 130; it can also be local routes of the first boundary node (such as loopback routes) or routing information generated according to local policies (such as aggregated routes), such as... Figure 1 The fourth node 140 contains local routes (such as loopback routes) or routing information generated according to local policies (such as aggregated routes).

[0040] Step S102: The routing information is advertised to the second boundary node through the first BGP message, so that the second boundary node establishes the shortest forwarding path to the first target prefix corresponding to the first algorithm information based on the first algorithm information and the first target prefix information in the routing information.

[0041] In one embodiment, when a first border node obtains routing information from a first IGP domain, and the routing information includes first algorithm information and first target prefix information corresponding to the first algorithm information, the first border node can construct a first BGP message based on the first algorithm information and the first target prefix information in the routing information, and then announce the routing information to a second border node through the first BGP message. That is, the first border node announces the first algorithm information and the first target prefix information to the second border node through the first BGP message, so that after receiving the first BGP message, the second border node can establish the shortest forwarding path to the first target prefix corresponding to the first algorithm information based on the first algorithm information and the first target prefix information carried in the first BGP message.

[0042] It should be noted that the first target prefix information is the routing reachability information of the first target prefix. Since the first target prefix information comes from the first IGP domain, that is, the first target prefix guided by the first target prefix information belongs to the first IGP domain, this embodiment can establish a cross-domain shortest forwarding path from the second IGP domain to the first IGP domain corresponding to the first algorithm information. That is, it can realize the establishment of cross-domain algorithm-based shortest forwarding path, thereby filling the technical gap in the creation of cross-domain paths related to algorithms in related technologies.

[0043] In one embodiment, the first BGP message is provided with an algorithm extension field, and the algorithm extension field in the first BGP message carries the first algorithm information.

[0044] The following example illustrates the algorithm extension field in the first BGP message.

[0045] In one embodiment, based on standard RFC 4360, an extended community attribute (i.e., an algorithm extension field) can be added to the first BGP message. This newly added algorithm extension field is defined as Algorithm Extended Community and is used to carry first algorithm information when announcing the first BGP message. The structure of this newly added algorithm extension field is as follows: Figure 3 As shown, in Figure 3 The newly added algorithm extension field includes the following field structure:

[0046] Type: Occupies 1 byte. When the value is 0x03, it indicates that the extended field of this algorithm is a transitive extended community attribute.

[0047] Sub-Type: Occupies 1 byte, indicating that the extended field of this algorithm is Algorithm Extended Community.

[0048] Flags: Occupies 1 byte, meaning to be determined, and can be expanded to define corresponding flag bits according to actual use.

[0049] Algorithm: Occupies 1 byte and represents the corresponding algorithm information. A value of 0 indicates that the constraint condition for this algorithm information is the Shortest Path First algorithm based on link metric; a value of 1 indicates that the constraint condition for this algorithm information is the Strict Shortest Path First algorithm based on link metric; and a value between 128 and 255 indicates that this algorithm information is a custom, flexible algorithm.

[0050] Reserved: Occupies 4 bytes, meaning to be determined, and can be expanded to include corresponding content based on actual usage.

[0051] By employing the path establishment method including the aforementioned steps S101 and S102, after obtaining routing information including first algorithm information and first target prefix information corresponding to the first algorithm information, the first boundary node of the first IGP domain can advertise the first algorithm information and the first target prefix information to the second boundary node of the second IGP domain via a first BGP message. This allows the first target prefix information corresponding to the first algorithm information from the first IGP domain to be advertised to a second IGP domain different from the first IGP domain. Consequently, the second boundary node of the second IGP domain can establish the shortest forwarding path to the first target prefix in the first IGP domain based on the first algorithm information and the first target prefix information, and this shortest forwarding path corresponds to the first algorithm information. Therefore, this embodiment can realize the establishment of cross-domain algorithm-based shortest forwarding paths, thereby filling the technical gap in algorithm-related cross-domain path creation in related technologies.

[0052] In one embodiment, such as Figure 4 As shown, the path establishment method may also include, but is not limited to, steps S103 and S104.

[0053] Step S103: Obtain the second BGP message sent by the second boundary node, wherein the second BGP message carries second algorithm information and second target prefix information corresponding to the second algorithm information.

[0054] It should be noted that the second algorithm information is the algorithm information defined in IGP Flex-algo. The second algorithm information is used to distinguish virtual topologies created by IGP Flex-algo. Virtual topologies with the same algorithm information can be classified as the same virtual topology, while different virtual topologies have different algorithm information.

[0055] In this step, since a BGP neighbor relationship is established between the first boundary node of the first IGP domain and the second boundary node of the second IGP domain, when the second boundary node announces a second BGP message carrying second algorithm information and second target prefix information corresponding to the second algorithm information, the first boundary node can obtain the second BGP message so that it can perform relevant path creation processing based on the second algorithm information and second target prefix information carried in the second BGP message in subsequent steps.

[0056] It should be noted that the second algorithm information and second destination prefix information carried in the second BGP message can be local routing information from the second boundary node, or routing information from other nodes in the second IGP domain. This embodiment does not specifically limit this. For example, the second algorithm information and second destination prefix information carried in the second BGP message can be local routing information from the second boundary node, or routing information from other nodes in the second IGP domain. Figure 1 The local routing information of the fifth node 150 (such as loopback routes or aggregated routes), or information from... Figure 1 Routing information for the sixth node 160, the seventh node 170, or the eighth node 180.

[0057] Step S104: Based on the second algorithm information and the second target prefix information, establish the shortest forwarding path to the second target prefix corresponding to the second algorithm information.

[0058] In one embodiment, when a first boundary node receives a second BGP message sent by a second boundary node, and the second BGP message carries second algorithm information and second target prefix information corresponding to the second algorithm information, the first boundary node can establish the shortest forwarding path to the second target prefix corresponding to the second algorithm information based on the second algorithm information and the second target prefix information in the second BGP message.

[0059] It should be noted that the second target prefix information is the routing reachability information of the second target prefix. Since the second target prefix information comes from the second IGP domain, that is, the second target prefix guided by the second target prefix information belongs to the second IGP domain, this embodiment can establish a cross-domain shortest forwarding path corresponding to the second algorithm information from the first IGP domain to the second IGP domain. That is, it can realize the establishment of a cross-domain algorithm-based shortest forwarding path, thereby filling the technical gap in the creation of cross-domain paths related to algorithms in related technologies.

[0060] In one embodiment, the second BGP message is provided with an algorithm extension field, and the algorithm extension field in the second BGP message carries the second algorithm information.

[0061] It should be noted that, based on the standard RFC4360, an extended community attribute (i.e., an algorithm extension field) can be added to the second BGP message to carry second algorithm information when announcing the second BGP message. It is important to note that the specific structure and meaning of the newly added algorithm extension field in the second BGP message are different from those in the standard RFC4360. Figure 3 The structure and meaning of the algorithm extension field added in the first BGP message are consistent with those shown. For an explanation of the structure and meaning of the algorithm extension field added in the second BGP message, please refer to [example...]. Figure 3 The specific structure and meaning of the newly added algorithm extension field in the first BGP message in the illustrated embodiment will not be repeated here.

[0062] In one embodiment, such as Figure 5 As shown, the path establishment method may also include, but is not limited to, steps S105 and S106.

[0063] Step S105: Construct a first IGP message, which carries second algorithm information and second target prefix information.

[0064] In this step, because in such Figure 4 In step S103 of the illustrated embodiment, a second BGP message sent by the second boundary node is obtained, and the second BGP message carries second algorithm information and second target prefix information corresponding to the second algorithm information. Therefore, the first boundary node can construct a first IGP message based on the second algorithm information and the second target prefix information, so that the first IGP message carries the second algorithm information and the second target prefix information, so that subsequent steps can flood the second algorithm information and the second target prefix information in the first IGP domain through the first IGP message.

[0065] It is worth noting that the first IGP message can have different implementations depending on the protocol running in the first IGP domain, and this embodiment does not specifically limit it. For example, the first IGP message can be an ISIS (Intermediate System to Intermediate System) message, or an OSPF (Open Shortest Path First) message, such as an OSPFv2 message based on an IPv4 network or an OSPFv3 message based on an IPv6 network.

[0066] Step S106: Flood the second algorithm information and the second target prefix information in the first IGP domain through the first IGP message, so that other nodes in the first IGP domain can establish the shortest forwarding path to the second target prefix corresponding to the second algorithm information based on the second algorithm information and the second target prefix information.

[0067] In this step, since a first IGP packet carrying the second algorithm information and the second target prefix information was constructed in step S105, the first boundary node can flood the first IGP packet in the first IGP domain. That is, by flooding the first IGP packet, the purpose of flooding the second algorithm information and the second target prefix information is achieved. Because the second algorithm information and the second target prefix information can be flooded in the first IGP domain, other nodes in the first IGP domain can obtain the second algorithm information and the second target prefix information. Therefore, any node in the first IGP domain can, according to its local policy, use the second algorithm information and the second target prefix information to establish the shortest forwarding path corresponding to the second algorithm information to the second target prefix, thereby realizing the establishment of cross-domain algorithm-based shortest forwarding paths and filling the technical gap in algorithm-related cross-domain path creation in related technologies.

[0068] In one embodiment, such as Figure 6 As shown, the path establishment method may also include, but is not limited to, steps S107, S108 and S109.

[0069] It should be noted that steps S107 to S109 in this embodiment are the same as those described above. Figure 5 Steps S105 to S106 in the illustrated embodiment are parallel technical solutions.

[0070] Step S107: Obtain the third algorithm information obtained by mapping the second algorithm information.

[0071] In one embodiment, when the flexible algorithm planes to which the first boundary node and the second boundary node belong have different algorithm information, in order to establish a cross-domain shortest forwarding path based on algorithm information, the first boundary node, in such a way... Figure 4 In step S103 of the illustrated embodiment, after obtaining the second BGP message carrying the second algorithm information and the second target prefix information sent by the second boundary node, the first boundary node can perform mapping processing on the second algorithm information to obtain the third algorithm information formed by mapping the second algorithm information, thereby forming a mapping relationship between the two flexible algorithm planes.

[0072] It should be noted that the method of establishing the mapping relationship between the second algorithm information and the third algorithm information is not specifically limited in this embodiment. For example, a mapping relationship similar to "<neighbor domain, algorithm information of neighbor domain> mapping <this domain, algorithm information of this domain>" can be established.

[0073] Step S108: Construct a second IGP message, which carries third algorithm information and second target prefix information.

[0074] In this step, since the third algorithm information corresponding to the flexible algorithm plane to which the first boundary node belongs was obtained in step S107 by mapping the second algorithm information, the first boundary node can construct a second IGP message based on the third algorithm information and the second target prefix information, so that the second IGP message carries the third algorithm information and the second target prefix information, so that subsequent steps can flood the third algorithm information and the second target prefix information in the first IGP domain through the second IGP message.

[0075] It is worth noting that the second IGP message can have different implementations depending on the protocol running in the first IGP domain, and this embodiment does not specifically limit this. For example, the second IGP message can be an ISIS message, an OSPF message, or an OSPFv3 message that supports IPv6.

[0076] Step S109: Flood the third algorithm information and the second target prefix information in the first IGP domain through the second IGP message, so that other nodes in the first IGP domain can establish the shortest forwarding path to the second target prefix corresponding to the third algorithm information based on the third algorithm information and the second target prefix information.

[0077] In this step, since a second IGP packet carrying the third algorithm information and the second target prefix information was constructed in step S108, the first boundary node can flood the second IGP packet in the first IGP domain, that is, flood the second IGP packet to achieve the purpose of flooding the third algorithm information and the second target prefix information. Since the third algorithm information and the second target prefix information can be flooded in the first IGP domain, other nodes in the first IGP domain can obtain the third algorithm information and the second target prefix information. Therefore, any node in the first IGP domain can, according to its local policy, use the third algorithm information and the second target prefix information to establish the shortest forwarding path to the second target prefix corresponding to the third algorithm information. Since the third algorithm information is formed by mapping the second algorithm information, the shortest forwarding path to the second target prefix established by the nodes in the first IGP domain using the third algorithm information and the second target prefix information can correspond to the second algorithm information. In the first boundary node, the path corresponding to the third algorithm information and the path corresponding to the second algorithm information can be concatenated, thereby realizing the establishment of the shortest forwarding path based on the algorithm across domains, filling the technical gap in the creation of cross-domain paths related to algorithms in related technologies.

[0078] In one embodiment, such as Figure 7 As shown, the path establishment method may also include, but is not limited to, steps S110 and S111.

[0079] It should be noted that steps S110 to S111 in this embodiment are the same as those described above. Figure 5 Steps S105 to S106 in the illustrated embodiment, as described above Figure 6 Steps S107 to S109 in the illustrated embodiments are all parallel technical solutions.

[0080] Step S110: Construct a third BGP message, which carries the second algorithm information and the second target prefix information.

[0081] In this step, because in such Figure 4In step S103 of the illustrated embodiment, a second BGP message sent by the second boundary node is obtained. The second BGP message carries second algorithm information and second target prefix information corresponding to the second algorithm information. Therefore, the first boundary node can construct a third BGP message based on the second algorithm information and the second target prefix information, so that the third BGP message carries the second algorithm information and the second target prefix information, so that subsequent steps can announce the third BGP message to other boundary nodes in the first IGP domain to announce the second algorithm information and the second target prefix information.

[0082] It should be noted that, based on the standard RFC4360, an extended community attribute (i.e., an algorithm extension field) can be added to the third BGP message to carry second algorithm information when advertising the third BGP message. It is important to note that the specific structure and meaning of the newly added algorithm extension field in the third BGP message are different from those in other languages. Figure 3 The structure and meaning of the algorithm extension field added in the first BGP message are consistent with those shown. For an explanation of the structure and meaning of the algorithm extension field added in the third BGP message, please refer to... Figure 3 The specific structure and meaning of the newly added algorithm extension field in the first BGP message in the illustrated embodiment will not be repeated here.

[0083] Step S111: The second algorithm information and the second target prefix information are announced to other boundary nodes in the first IGP domain through the third BGP message, so that the other boundary nodes in the first IGP domain can establish the shortest forwarding path to the second target prefix corresponding to the second algorithm information based on the second algorithm information and the second target prefix information.

[0084] In this step, since a third BGP message carrying the second algorithm information and the second target prefix information is constructed in step S110, the first boundary node can use the third BGP message to announce the second algorithm information and the second target prefix information to other boundary nodes in the first IGP domain. When other boundary nodes in the first IGP domain receive the third BGP message, they can use the second algorithm information and the second target prefix information to establish the shortest forwarding path to the second target prefix corresponding to the second algorithm information according to their local policies. This realizes the establishment of cross-domain algorithm-based shortest forwarding path, filling the technical gap in algorithm-related cross-domain path creation in related technologies.

[0085] It should be noted that when the first border node constructs the third BGP message, it can set the content of the next-hop field in the third BGP message to the address of the first border node. Therefore, when other border nodes in the first IGP domain receive the third BGP message announced by the first border node, they can generate a forwarding table entry to the second target prefix based on the content of the next-hop field, the second algorithm information, and the second target prefix information in the third BGP message. This forwarding table entry will then iterate to the outermost forwarding path corresponding to the second algorithm information with the first border node as the next hop, thereby establishing the algorithm-based shortest forwarding path from other border nodes in the first IGP domain to the second IGP domain.

[0086] In one embodiment, such as Figure 8 As shown, the path establishment method may also include, but is not limited to, steps S112, S113 and S114.

[0087] It should be noted that steps S112 to S114 in this embodiment are the same as those described above. Figure 5 Steps S105 to S106 in the illustrated embodiment, as described above Figure 6 Steps S107 to S109 in the illustrated embodiment, as described above Figure 7 Steps S110 to S111 in the illustrated embodiments are all parallel technical solutions.

[0088] Step S112: Obtain the fourth algorithm information obtained by mapping the second algorithm information.

[0089] In one embodiment, when the flexible algorithm planes to which the first boundary node and the second boundary node belong have different algorithm information, in order to establish a cross-domain shortest forwarding path based on algorithm information, the first boundary node, in such a way... Figure 4 In step S103 of the illustrated embodiment, after obtaining the second BGP message carrying the second algorithm information and the second target prefix information sent by the second boundary node, the first boundary node can perform mapping processing on the second algorithm information to obtain the fourth algorithm information formed by mapping the second algorithm information, thereby forming a mapping relationship between the two flexible algorithm planes.

[0090] It should be noted that the method of establishing the mapping relationship between the second algorithm information and the fourth algorithm information is not specifically limited in this embodiment. For example, a mapping relationship similar to "<neighbor domain, algorithm information of neighbor domain> mapping <this domain, algorithm information of this domain>" can be established.

[0091] Step S113: Construct a fourth BGP message, which carries fourth algorithm information and second target prefix information.

[0092] In this step, since the fourth algorithm information corresponding to the flexible algorithm plane to which the first boundary node belongs was obtained in step S112 by mapping the second algorithm information, the first boundary node can construct a fourth BGP message based on the fourth algorithm information and the second target prefix information, so that the fourth BGP message carries the fourth algorithm information and the second target prefix information, so that subsequent steps can announce the fourth BGP message to other boundary nodes in the first IGP domain to announce the fourth algorithm information and the second target prefix information.

[0093] It should be noted that, based on the standard RFC4360, an extended community attribute (i.e., an algorithm extension field) can be added to the fourth BGP message to carry fourth algorithm information when advertising the fourth BGP message. It is important to note that the specific structure and meaning of the newly added algorithm extension field in the fourth BGP message are different from those in other languages. Figure 3 The structure and meaning of the algorithm extension field added in the first BGP message are consistent with those shown. For an explanation of the structure and meaning of the algorithm extension field added in the fourth BGP message, please refer to [example...]. Figure 3 The specific structure and meaning of the newly added algorithm extension field in the first BGP message in the illustrated embodiment will not be repeated here.

[0094] Step S114: The fourth algorithm information and the second target prefix information are announced to other boundary nodes in the first IGP domain through the fourth BGP message, so that the other boundary nodes in the first IGP domain can establish the shortest forwarding path to the second target prefix corresponding to the fourth algorithm information based on the fourth algorithm information and the second target prefix information.

[0095] In this step, since a fourth BGP message carrying the fourth algorithm information and the second target prefix information is constructed in step S113, the first boundary node can announce the fourth algorithm information and the second target prefix information to other boundary nodes in the first IGP domain through this fourth BGP message. When other boundary nodes in the first IGP domain receive the fourth BGP message, they can establish the shortest forwarding path to the second target prefix corresponding to the fourth algorithm information according to their local policies, using the fourth algorithm information and the second target prefix information. Since the fourth algorithm information is formed by mapping the second algorithm information, the shortest forwarding path to the second target prefix established by other boundary nodes in the first IGP domain using the fourth algorithm information and the second target prefix information can correspond to the second algorithm information. In the first boundary node, the path corresponding to the fourth algorithm information and the path corresponding to the second algorithm information can be concatenated, thereby realizing the establishment of a cross-domain algorithm-based shortest forwarding path, filling the technical gap in algorithm-related cross-domain path creation in related technologies.

[0096] It should be noted that when the first border node constructs the fourth BGP message, it can set the content of the next-hop field in the fourth BGP message to the address of the first border node. Therefore, when other border nodes in the first IGP domain receive the fourth BGP message announced by the first border node, they can generate a forwarding table entry to the second target prefix based on the content of the next-hop field, the fourth algorithm information, and the second target prefix information in the fourth BGP message. This forwarding table entry will then iterate to the outermost forwarding path corresponding to the fourth algorithm information with the first border node as the next hop, thereby establishing the algorithm-based shortest forwarding path from other border nodes in the first IGP domain to the second IGP domain.

[0097] To more clearly illustrate the process of path establishment, a specific example will be provided below.

[0098] Example 1:

[0099] In such Figure 1 In the network topology shown, the network is a pure IP network. The network deploys a first IGP domain and a second IGP domain. The first IGP domain includes a first node 110, a second node 120, a third node 130, and a fourth node 140. The second IGP domain includes a fifth node 150, a sixth node 160, a seventh node 170, and an eighth node 180. The second node 120 and the fourth node 140 are both boundary nodes of the first IGP domain, and the fifth node 150 and the seventh node 170 are both boundary nodes of the second IGP domain. The network deploys a first flexible algorithm plane, a second flexible algorithm plane, a third flexible algorithm plane, and a fourth flexible algorithm plane. The first and third flexible algorithm planes are both Flex-algo 128, and the second and fourth flexible algorithm planes are both Flex-algo 129. That is, the Flex-algo 128 plane in the first IGP domain and the Flex-algo 128 plane in the second IGP domain constitute an end-to-end cross-domain Flex-algo 128 plane, and the Flex-algo 129 plane in the first IGP domain and the Flex-algo 129 plane in the second IGP domain constitute an end-to-end cross-domain Flex-algo 129 plane.

[0100] Nodes 110, 120, and 140 belong to the Flex-algo 128 plane in the first IGP domain; nodes 150, 160, and 170 belong to the Flex-algo 128 plane in the second IGP domain; nodes 120, 130, and 140 belong to the Flex-algo 129 plane in the first IGP domain; and nodes 150, 170, and 180 belong to the Flex-algo 129 plane in the second IGP domain. BGP neighbor relationships are established between nodes 120 and 140, 140 and 150, and 150 and 170 to advertise public network prefix reachability information.

[0101] Assuming that two loopback routes, loopback-E1 and loopback-E2, are configured on the seventh node 170, and these two loopback routes belong to the Flex-algo 128 plane and the Flex-algo 129 plane respectively, then routes to loopback-E1 will be generated on the fifth node 150, the sixth node 160, and the seventh node 170, while routes to loopback-E2 will be generated on the fifth node 150, the seventh node 170, and the eighth node 180.

[0102] In related technologies, such as the methods for advertising IPv4 and IPv6 prefixes using BGP messages in standards RFC4271 and RFC2545, in order to establish an end-to-end cross-domain route from the second node 120 to the seventh node 170, the fifth node 150 can advertise Prefix loopback-E1 and Prefix loopback-E2 to the fourth node 140 via BGP messages. However, in these related technologies, when advertising Prefix loopback-E1 and Prefix loopback-E2, the algorithm information corresponding to the Flex-algo 128 plane and the Flex-algo 129 plane is lost. As a result, the fourth node 140 does not know which Flex-algo plane in the first IGP domain to import loopback-E1 or loopback-E2 into. To address this issue, in this example, when the fifth node 150 announces Prefix loopback-E1 to the fourth node 140 via BGP, it carries the algorithm information corresponding to the Flex-algo 128 plane; while when it announces Prefix loopback-E2 to the fourth node 140, it carries the algorithm information corresponding to the Flex-algo 129 plane.

[0103] When the fourth node 140 receives a BGP message from the fifth node 150, it can directly import the Prefix loopback-E1 corresponding to the Flex-algo 128 plane carried in the BGP message into the Flex-algo 128 plane of the first IGP domain. That is, when the fourth node 140 continues to advertise Prefix loopback-E1 to the first node 110 and the third node 130, it will directly carry the algorithm information corresponding to the Flex-algo 128 plane, making Prefix loopback-E1 effective only in the Flex-algo 128 plane of the first IGP domain. Similarly, the fourth node 140 will also advertise Prefix loopback-E2 and the algorithm information corresponding to the Flex-algo 129 plane to the first node 110 and the third node 130, making Prefix loopback-E2 effective only in the Flex-algo 129 plane of the first IGP domain.

[0104] After the first node 110 and the third node 130 receive the information announced by the fourth node 140, they will continue to announce the Prefix loopback-E1 corresponding to the Flex-algo 128 plane and the Prefix loopback-E2 corresponding to the Flex-algo 129 plane to the second node 120. Finally, the second node 120 will generate shortest path forwarding table entries to Prefix loopback-E1 corresponding to the Flex-algo 128 plane, and to Prefix loopback-E2 corresponding to the Flex-algo 129 plane, thereby achieving end-to-end algorithm-based cross-domain shortest forwarding path.

[0105] Example 2:

[0106] The network topology in this example is similar to that in Example 1 above, except that the first flexible algorithm plane is Flex-algo 228 and the second flexible algorithm plane is Flex-algo 229.

[0107] In this example, after the fourth node 140 receives the BGP message from the fifth node 150, before importing the Prefix loopback-E1 corresponding to the Flex-algo 128 plane carried in the BGP message into the Flex-algo 228 plane of the first IGP domain, the fourth node 140 first maps the algorithm information corresponding to the Flex-algo 128 plane to the algorithm information corresponding to the Flex-algo 228 plane. Then, it notifies the first node 110 and the third node 130 of Prefix loopback-E1 and Prefix loopback-E2 respectively. Furthermore, when the fourth node 140 notifies the first node 110 and the third node 130 of Prefix loopback-E1 and Prefix loopback-E2 respectively, it carries the algorithm information corresponding to the Flex-algo 228 plane and the algorithm information corresponding to the Flex-algo 229 plane respectively. This ensures that Prefix loopback-E1 only takes effect in the Flex-algo 228 plane of the first IGP domain, while Prefix... loopback-E2 is only effective in the Flex-algo 229 plane in the first IGP domain.

[0108] It should be noted that this example only describes the differences between this example and Example 1 above. For the similarities between this example and Example 1 above, please refer to the relevant descriptions in Example 1 above, which will not be repeated here.

[0109] Example 3:

[0110] The network topology in this example is similar to that in Example 1 above, except that the network in this example is an SRv6 network.

[0111] Assuming that two SRv6 Locator routes, LOC-E1 and LOC-E2, are configured on the seventh node 170, and these two SRv6 Locator routes belong to the Flex-algo 128 plane and the Flex-algo 129 plane respectively, then routes to LOC-E1 will be generated on the fifth node 150, the sixth node 160, and the seventh node 170, while routes to LOC-E2 will be generated on the fifth node 150, the seventh node 170, and the eighth node 180.

[0112] When the fifth node 150 announces Prefix LOC-E1 to the fourth node 140 via BGP message, it carries the algorithm information corresponding to the Flex-algo 128 plane. When it announces Prefix LOC-E2 to the fourth node 140, it carries the algorithm information corresponding to the Flex-algo 129 plane.

[0113] When the fourth node 140 receives a BGP message from the fifth node 150, it imports the Prefix LOC-E1 corresponding to the Flex-algo 128 plane carried in the BGP message into the Flex-algo 128 plane of the first IGP domain. That is, when the fourth node 140 continues to advertise Prefix LOC-E1 to the first node 110 and the third node 130, it will directly carry the algorithm information corresponding to the Flex-algo 128 plane, making Prefix LOC-E1 effective only in the Flex-algo 128 plane of the first IGP domain. Similarly, the fourth node 140 will also advertise Prefix LOC-E2 and the algorithm information corresponding to the Flex-algo 129 plane to the first node 110 and the third node 130, making Prefix LOC-E2 effective only in the Flex-algo 129 plane of the first IGP domain.

[0114] After the first node 110 and the third node 130 receive the information announced by the fourth node 140, they will continue to announce the Prefix LOC-E1 corresponding to the Flex-algo 128 plane and the Prefix LOC-E2 corresponding to the Flex-algo 129 plane to the second node 120. Finally, the second node 120 will generate shortest path forwarding table entries to Prefix LOC-E1 corresponding to the Flex-algo 128 plane, and to Prefix LOC-E2 corresponding to the Flex-algo 129 plane, thereby achieving end-to-end algorithm-based cross-domain shortest forwarding path.

[0115] Example 4:

[0116] The network topology in this example is similar to that in Example 1 above, except that the network in this example is an SR-MPLS network.

[0117] Assume that node 7 (170) is configured with two Prefix-SIDs, denoted as SID-E1 and SID-E2. These two Prefix-SIDs belong to the Flex-algo 128 and Flex-algo 129 planes respectively, and are flooded in the second IGP domain along with the loopback route (loopback-E) of node 7 (170). Then, MPLS label forwarding paths to Prefix-SID SID-E1 will be generated on nodes 5 (150), 6 (160), and 7 (170), while MPLS label forwarding paths to Prefix-SID SID-E2 will be generated on nodes 5 (150), 7 (170), and 8 (180).

[0118] When the fifth node 150 announces Prefix loopback-E and its Prefix-SID SID-E1 to the fourth node 140 via BGP message, it carries the algorithm information corresponding to the Flex-algo 128 plane. When it announces Prefix loopback-E and its Prefix-SID SID-E2 to the fourth node 140, it carries the algorithm information corresponding to the Flex-algo 129 plane.

[0119] When the fourth node 140 receives the BGP message from the fifth node 150, the fourth node 140 imports the Prefix-SID SID-E1 corresponding to the Flex-algo 128 plane carried in the BGP message into the Flex-algo 128 plane of the first IGP domain. That is, when the fourth node 140 continues to announce the Prefix loopback-E and its Prefix-SID SID-E1 to the first node 110 and the third node 130, it will directly carry the algorithm information corresponding to the Flex-algo 128 plane, so that the Flex-algo 128 plane in the first IGP domain establishes an MPLS label forwarding table entry to Prefix-SID SID-E1. Similarly, when the fourth node 140 announces Prefix loopback-E and its Prefix-SID SID-E2 to the first node 110 and the third node 130, it will directly carry the algorithm information corresponding to the Flex-algo 129 plane, so that the Flex-algo 129 plane in the first IGP domain establishes an MPLS label forwarding table entry to Prefix-SID SID-E2.

[0120] After receiving the information announced by the fourth node 140, the first node 110 and the third node 130 will continue to announce Prefix loopback-E and its Prefix-SID SID-E1 to the second node 120, carrying the algorithm information corresponding to the Flex-algo 128 plane in the announcement. They will also announce Prefix loopback-E and its Prefix-SID SID-E2 to the second node 120, carrying the algorithm information corresponding to the Flex-algo 129 plane in the announcement. Finally, the second node 120 will generate MPLS label forwarding table entries corresponding to the Flex-algo 128 plane up to Prefix-SID SID-E1, and MPLS label forwarding table entries corresponding to the Flex-algo 129 plane up to Prefix-SID SID-E2, thereby achieving an end-to-end algorithm-based cross-domain shortest forwarding path.

[0121] Example 5:

[0122] The network topology in this example is similar to that in Example 4 above, except that when the fourth node 140 receives a BGP message from the fifth node 150, the fourth node 140 does not import the Prefix-SID SID-E1 corresponding to the Flex-algo 128 plane carried in the BGP message into the Flex-algo 128 plane of the first IGP domain. Instead, it announces the Prefix-SID SID-E1 corresponding to the Flex-algo 128 plane to the second node 120 through a new BGP message.

[0123] When the fourth node 140 receives the BGP message from the fifth node 150, the fourth node 140 first obtains the Prefix-SID SID-E1 corresponding to the Flex-algo 128 plane carried in the BGP message, then constructs a new BGP message carrying the Prefix-SID SID-E1, and sets the content of the next-hop field in the new BGP message to the address information of the fourth node 140 itself, and then announces the Prefix-SID SID-E1 corresponding to the Flex-algo 128 plane to the second node 120 through the new BGP message. When the second node 120 obtains the new BGP packet from the fourth node 140 through the BGP neighbor relationship, the second node 120 will generate an MPLS label forwarding table entry for Prefix-SID SID-E1, and this MPLS label forwarding table entry will continue to iterate to the outermost forwarding path corresponding to the Flex-algo 128 plane with the fourth node 140 as the next hop; in addition, the second node 120 will also generate an MPLS label forwarding table entry for Prefix-SID SID-E2, and this MPLS label forwarding table entry will continue to iterate to the outermost forwarding path corresponding to the Flex-algo 129 plane with the fourth node 140 as the next hop.

[0124] Finally, on the second node 120, MPLS label forwarding table entries corresponding to the Flex-algo 128 plane for Prefix-SID SID-E1 and MPLS label forwarding table entries corresponding to the Flex-algo 129 plane for Prefix-SID SID-E2 will be generated, thereby realizing end-to-end algorithm-based shortest forwarding path across domains.

[0125] In addition, such as Figure 9 As shown, one embodiment of the present invention also provides a path establishment apparatus 200, which includes: a memory 201, a processor 202, and a computer program stored in the memory 201 and executable on the processor 202.

[0126] The processor 202 and the memory 201 can be connected via a bus or other means.

[0127] Memory 201, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory 201 may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory 201 may optionally include memory remotely located relative to processor 202, and these remote memories can be connected to processor 202 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0128] It should be noted that the path establishment device 200 in this embodiment can be applied to, for example... Figure 1 The fourth node 140 or the fifth node 150 in the illustrated embodiment can be configured by the path establishment device 200 in this embodiment. Figure 1 The network topology shown in the embodiments is part of the network topology. These embodiments all belong to the same inventive concept, and therefore have the same implementation principle and technical effect, which will not be described in detail here.

[0129] The non-transitory software program and instructions required to implement the path establishment method of the above embodiments are stored in memory. When executed by a processor, the path establishment method in the above embodiments is executed, for example, the method described above is executed. Figure 2 Method steps S101 to S102 in the text Figure 4 Method steps S103 to S104 in the text Figure 5 Method steps S105 to S106 in the text Figure 6 Method steps S107 to S109 in the text Figure 7 Method steps S110 to S111 in the text Figure 8 Method steps S112 to S114.

[0130] In addition, such as Figure 10 As shown, one embodiment of the present invention also provides a node, the node 300 including as follows Figure 9 The path establishment device 200 in the illustrated embodiment.

[0131] It should be noted that node 300 in this embodiment includes, for example, Figure 9 The path establishment device 200 in the illustrated embodiment can be applied as follows: Figure 1 The fourth node 140 or the fifth node 150 in the illustrated embodiment, and the node 300 in this embodiment can constitute Figure 1 The network topology shown in the embodiments is part of the network topology. These embodiments all belong to the same inventive concept, and therefore have the same implementation principle and technical effect, which will not be described in detail here.

[0132] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0133] Furthermore, one embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions that are executed by a processor or controller, for example, by a processor in the above-described device embodiment, causing the processor to perform the path establishment method in the above-described embodiment, for example, performing the above-described... Figure 2 Method steps S101 to S102 in the text Figure 4 Method steps S103 to S104 in the text Figure 5 Method steps S105 to S106 in the text Figure 6 Method steps S107 to S109 in the text Figure 7 Method steps S110 to S111 in the text Figure 8 Method steps S112 to S114.

[0134] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0135] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A path establishment method, applied to a first border node of a first Interior Gateway Protocol (IGP) domain, wherein the first border node is connected to a second border node of a second IGP domain, and a Border Gateway Protocol (BGP) neighbor relationship is established between the first border node and the second border node, the method comprising: Obtain routing information from the first IGP domain, wherein the routing information includes first algorithm information and first target prefix information corresponding to the first algorithm information; The routing information is announced to the second border node via a first border gateway protocol (BGP) message, so that the second border node establishes the shortest forwarding path to the first target prefix corresponding to the first algorithm information based on the first algorithm information and the first target prefix information in the routing information.

2. The method according to claim 1, characterized in that, The method further includes: Obtain the second BGP message sent by the second boundary node, wherein the second BGP message carries second algorithm information and second target prefix information corresponding to the second algorithm information; Based on the second algorithm information and the second target prefix information, the shortest forwarding path to the second target prefix corresponding to the second algorithm information is established.

3. The method according to claim 2, characterized in that, Both the first BGP message and the second BGP message have an algorithm extension field. The algorithm extension field in the first BGP message carries the first algorithm information, and the algorithm extension field in the second BGP message carries the second algorithm information.

4. The method according to claim 2, characterized in that, The method further includes: Construct a first IGP message, the first IGP message carrying the second algorithm information and the second target prefix information; By flooding the second algorithm information and the second target prefix information in the first IGP domain through the first IGP message, other nodes in the first IGP domain can establish the shortest forwarding path to the second target prefix corresponding to the second algorithm information based on the second algorithm information and the second target prefix information.

5. The method according to claim 2, characterized in that, The method further includes: Obtain the third algorithm information obtained by mapping the second algorithm information; Construct a second IGP message, the second IGP message carrying the third algorithm information and the second target prefix information; By flooding the third algorithm information and the second target prefix information in the first IGP domain through the second IGP message, other nodes in the first IGP domain can establish the shortest forwarding path to the second target prefix corresponding to the third algorithm information based on the third algorithm information and the second target prefix information.

6. The method according to claim 2, characterized in that, The method further includes: Construct a third BGP message, the third BGP message carrying the second algorithm information and the second target prefix information; The second algorithm information and the second target prefix information are announced to other boundary nodes in the first IGP domain through the third BGP message, so that the other boundary nodes in the first IGP domain can establish the shortest forwarding path to the second target prefix corresponding to the second algorithm information based on the second algorithm information and the second target prefix information.

7. The method according to claim 2, characterized in that, The method further includes: Obtain the fourth algorithm information obtained by mapping the second algorithm information; A fourth BGP message is constructed, the fourth BGP message carrying the fourth algorithm information and the second target prefix information; The fourth BGP message announces the fourth algorithm information and the second target prefix information to other boundary nodes in the first IGP domain, enabling the other boundary nodes in the first IGP domain to establish the shortest forwarding path to the second target prefix corresponding to the fourth algorithm information based on the fourth algorithm information and the second target prefix information.

8. A path establishment apparatus, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, when the processor executes the computer program, it implements the path establishment method as described in any one of claims 1 to 7.

9. A network node, characterized in that, It includes the path establishment device as described in claim 8.

10. A computer-readable storage medium storing computer-executable instructions for performing the path establishment method according to any one of claims 1 to 7.

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