Cross-autonomous domain notification method, autonomous system border router, system and medium

Abstract

The present disclosure provides a cross-autonomous domain announcement method, an autonomous system border router, a system and a medium, and relates to the field of communication technology. The method comprises: obtaining unreachable prefix announcement related information from a received first unreachable prefix announcement message according to the internal gateway protocol IGP running in the first autonomous domain where the first autonomous system border router is located, and the unreachable prefix announcement related information includes unreachable prefix information, a first identification value and a second identification value; generating a BGP update message according to the unreachable prefix announcement related information, and the BGP update message includes the unreachable prefix announcement related information; sending a BGP update message to the second autonomous system border router, so that the second autonomous system border router broadcasts the unreachable prefix announcement related information in the second autonomous domain where the second autonomous system border router is located. The present disclosure can completely transmit the information contained in the original unreachable prefix announcement message, and realize the cross-domain transmission of unreachable prefixes.

Description

Background Art

[0002] In the cross-autonomous domain scenario of Border Gateway Protocol (BGP), the Autonomous System Boundary Routers (ASBRs) between different autonomous systems (AS) implement inter-domain advertisements. However, ASBRs do not advertise unreachable prefixes within their own autonomous domains.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0004] The present disclosure provides a cross-autonomous domain announcement method, an autonomous system border router, a system and a medium, which at least to a certain extent overcome the problem that the existing autonomous system border router does not announce the unreachable prefixes in the autonomous domain where it is located.

[0005] Other features and advantages of the present disclosure will become apparent from the following detailed description, or may be learned in part by the practice of the present disclosure.

[0006] According to one aspect of the present disclosure, a cross-autonomous domain announcement method is provided, which is applied to a first autonomous system border router; the method includes: obtaining unreachable prefix announcement related information from a received first unreachable prefix announcement message according to an internal gateway protocol IGP running in a first autonomous domain where the first autonomous system border router is located, the unreachable prefix announcement related information including unreachable prefix information, a first identification value and a second identification value; generating a border gateway protocol BGP update message according to the unreachable prefix announcement related information, wherein the BGP update message includes the unreachable prefix announcement related information; sending the BGP update message to a second autonomous system border router, so that the second autonomous system border router broadcasts the unreachable prefix announcement related information in a second autonomous domain where the second autonomous system border router is located.

[0007] In one embodiment of the present disclosure, the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a revoked route field; the revoked route field includes a first identification bit, a second identification bit and an unreachable prefix field; wherein, generating a Border Gateway Protocol BGP update message based on the unreachable prefix announcement related information includes: setting the sub-address cluster identification field to a value corresponding to the unreachable prefix announcement type; setting the first identification bit to a first identification value; setting the second identification bit to a second identification value, the first identification value indicating that the unreachability is caused by unplanned reasons, and the second identification value indicating that the unreachability is caused by planned reasons; and writing the unreachable prefix information into the unreachable prefix field.

[0008] In one embodiment of the present disclosure, the revocation route field also includes a length field; the method also includes: determining the total length of the unreachable prefix based on the unreachable prefix information, and writing the total length of the unreachable prefix into the length field, wherein the unreachable prefix information includes at least one unreachable prefix.

[0009] In one embodiment of the present disclosure, the internal gateway protocol IGP run by the first autonomous domain and the second autonomous domain includes at least one of the IS-IS protocol and the OSPF protocol.

[0010] According to another aspect of the present disclosure, a first autonomous system border router is provided, including: a first extraction module, used to obtain unreachable prefix announcement related information from a received first unreachable prefix announcement message based on an internal gateway protocol IGP running in a first autonomous domain where the first autonomous system border router is located, the unreachable prefix announcement related information including unreachable prefix information, a first identification value and a second identification value; a message generation module, used to generate a border gateway protocol BGP update message based on the unreachable prefix announcement related information, wherein the BGP update message includes the unreachable prefix announcement related information; a message sending module, used to send the BGP update message to a second autonomous system border router, so that the second autonomous system border router broadcasts the unreachable prefix announcement related information in a second autonomous domain where the second autonomous system border router is located.

[0011] According to another aspect of the present disclosure, a first autonomous system border router is provided, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to execute the cross-autonomous domain announcement method in the above embodiment by executing the executable instructions.

[0012] According to another aspect of the present disclosure, a cross-autonomous domain announcement method is provided, which is applied to a second autonomous system border router; the method includes: receiving a BGP update message sent by a first autonomous system border router, the BGP update message including information related to an unreachable prefix announcement, the unreachable prefix announcement information being obtained by the first autonomous system border router from a received first unreachable prefix announcement message according to an IGP running in a first autonomous domain where the first autonomous system border router is located, the unreachable prefix announcement information including unreachable prefix information, a first identification value and a second identification value; extracting the unreachable prefix announcement information from the BGP update message; generating a second unreachable prefix announcement message according to the IGP protocol running in a second autonomous domain where the second autonomous system border router is located and the unreachable prefix announcement information, and broadcasting it in the second autonomous domain.

[0013] In one embodiment of the present disclosure, the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a revoked route field; the revoked route field includes a first identification bit, a second identification bit and an unreachable prefix field; wherein, extracting the unreachable prefix announcement related information from the BGP update message includes: when the value of the sub-address cluster identification field extracted from the BGP update message is a value corresponding to the unreachable prefix announcement type, determining that the BGP update message is a message of the unreachable prefix announcement type; extracting the first identification bit, the second identification bit and the value of the unreachable prefix field from the BGP update message to obtain a first identification value, a second identification value and the unreachable prefix information, wherein the first identification value represents unreachable due to unplanned reasons, and the second identification value represents unreachable due to planned reasons.

[0014] In one embodiment of the present disclosure, the withdrawn route field also includes a length field; the method also includes: extracting the value of the length field from the BGP update message to determine the total length of the unreachable prefix, wherein the unreachable prefix information includes at least one unreachable prefix.

[0015] In one embodiment of the present disclosure, the internal gateway protocol IGP run by the first autonomous domain and the second autonomous domain includes at least one of the IS-IS protocol and the OSPF protocol.

[0016] According to another aspect of the present disclosure, a second autonomous system border router is provided, including: a message receiving module, used to receive a BGP update message sent by a first autonomous system border router, the BGP update message including unreachable prefix announcement related information, the unreachable prefix announcement related information is obtained by the first autonomous system border router from a first unreachable prefix announcement message received according to an internal gateway protocol IGP running in a first autonomous domain where the first autonomous system border router is located, the unreachable prefix announcement related information including unreachable prefix information, a first identification value and a second identification value; a second extraction module, used to extract the unreachable prefix announcement related information from the BGP update message; a message broadcasting module, used to generate a second unreachable prefix announcement message and broadcast it in the second autonomous domain according to the internal gateway protocol IGP running in the second autonomous domain where the second autonomous system border router is located and the unreachable prefix announcement related information.

[0017] According to another aspect of the present disclosure, a second autonomous system boundary router is provided, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to execute the cross-autonomous domain notification method of the above embodiment by executing the executable instructions.

[0018] According to another aspect of the present disclosure, a communication system is provided, including: a first autonomous domain, wherein the first autonomous system border router of the above embodiment is provided in the first autonomous domain; and a second autonomous domain, wherein the second autonomous domain is provided with the second autonomous system border router of the above embodiment.

[0019] According to another aspect of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the above-mentioned cross-autonomous domain notification method is implemented.

[0020] According to another aspect of the present disclosure, a computer program product is provided, which includes a computer program or computer instructions, and the computer program or the computer instructions are loaded and executed by a processor to enable a computer to implement the above-mentioned cross-autonomous domain notification method.

[0021] In an embodiment of the present disclosure, a first autonomous system border router obtains information related to an unreachable prefix announcement from a received first unreachable prefix announcement message based on an internal gateway protocol IGP running in a first autonomous domain where the first autonomous system border router is located, the information related to the unreachable prefix announcement including unreachable prefix information, a first identification value, and a second identification value; generates a border gateway protocol BGP update message based on the information related to the unreachable prefix announcement, the BGP update message including information related to the unreachable prefix announcement; and sends a BGP update message to a second autonomous system border router, so that the second autonomous system border router broadcasts the information related to the unreachable prefix announcement in a second autonomous domain where the second autonomous system border router is located. The present disclosure extends the BGP protocol so that a first autonomous system border router can encapsulate the received unreachable prefix announcement related information in a BGP message, and a second autonomous system border router that receives the BGP message can completely restore the unreachable prefix announcement related information carried in the original data packet, so as to realize cross-domain transmission of the unreachable prefix announcement information, allow routers located in different autonomous systems to promptly notify each other of the real-time status of links within their respective autonomous systems, and in a large cross-domain network, assist relevant personnel in locating the fault when a fault occurs, reduce the occurrence of routing and traffic black holes, and improve routing convergence efficiency.

[0022] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0024] Figure 1 An architectural diagram of a communication system in an embodiment of the present disclosure is shown.

[0025] Figure 2 An architectural diagram of another communication system in an embodiment of the present disclosure is shown.

[0026] Figure 3 A flow chart of a cross-autonomous domain notification method provided by an embodiment of the present disclosure is shown.

[0027] Figure 4 A schematic diagram of the structure of a first autonomous system border router provided in an embodiment of the present disclosure is shown.

[0028] Figure 5A schematic structural diagram of another first autonomous system border router provided by an embodiment of the present disclosure is shown.

[0029] Figure 6 A flow chart of another cross-autonomous domain notification method provided by an embodiment of the present disclosure is shown.

[0030] Figure 7 A schematic structural diagram of a second autonomous system border router provided by an embodiment of the present disclosure is shown.

[0031] Figure 8 A schematic diagram of the structure of another second autonomous system border router provided by an embodiment of the present disclosure is shown.

[0032] Fig. 9 A schematic diagram of a computer-readable storage medium provided by an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0033] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0034] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0035] For ease of understanding, before introducing the embodiments of the present disclosure, several terms involved in the embodiments of the present disclosure are explained as follows:

[0036] UPA: Unreachable Prefix Announcement, a mechanism for announcing unreachable prefix addresses.

[0037] AS: Autonomous System, or autonomous domain.

[0038] ASBR: Autonomous System Border Router, located between the Open Shortest Path First (OSPF) autonomous system and the non-OSPF network, can run OSPF and another selective protocol, such as RIP, and redistribute other routing protocols to OSPF.

[0039] IGP: Interior Gateway Protocol. It is a protocol for exchanging routing information between gateways (hosts and routers) within an autonomous domain.

[0040] BGP: Border Gateway Protocol. BGP is used to exchange routing information between different autonomous systems.

[0041] AFI: Address Family Identifier. This field, combined with the subsequent SAFI field, identifies a set of network layer protocols to which the address carried in the next hop field must belong, the encoding method of the next hop address, and the semantics of the subsequent network layer reachability information.

[0042] SAFI: Subsequent Address Family Identifier, which is combined with the AFI field to identify a set of network layer protocols to which the address carried in the next hop field must belong, the encoding method of the next hop address, and the semantics of the subsequent network layer reachability information.

[0043] IS-IS: Intermediate System to Intermediate System, an internal network management protocol.

[0044] OSPF, Open Shortest Path First, is a widely used IGP routing protocol.

[0045] IS-IS Bit Values ​​for Predix Attribute Flags Sub-TLV: Sub-TLV of IS-IS bit values ​​for prefix attribute flags.

[0046] Prefix Attributes Sub-TLV: prefix attribute sub-TLV.

[0047] TLV: Tag-length-Value, is a commonly used data serialization format used to encode the payload of a data packet or message.

[0048] Prefix Options: Prefix options.

[0049] Figure 1 FIG. 1 shows an architecture diagram of a communication system provided by an embodiment of the present disclosure. Figure 1 As shown, the communication system includes a first autonomous domain AS1 and a second autonomous domain AS2. The first autonomous domain AS1 includes a first autonomous system border router ASBR1, and the second autonomous domain AS2 includes a second autonomous system border router ASBR2. ASBR1 and ASBR2 exchange routing information between different autonomous systems through the Border Gateway Protocol BGP.

[0050] The first autonomous domain AS1 includes multiple routers, and the multiple routers obtain multiple links according to the network topology relationship; the second autonomous domain AS2 includes multiple routers, and the multiple routers obtain multiple links according to the network topology relationship. Figure 1 AS1 includes 4 routers, namely routers R1~R4, R3-R1 forms one link, R4-R2 forms another link. AS2 includes 4 routers, namely routers T1-T4, T1-T3 forms one link, T2-T4 forms another link.

[0051] exist Figure 2 In the figure, AS1 includes four routers, namely R1~R4. According to the network topology, three links are obtained, including the R4-R1 link in addition to the above two links.

[0052] It should be noted that the number of routers and the number of links in the first autonomous domain AS1 and the second autonomous domain AS2 are determined according to actual needs, and the present disclosure does not make any specific limitations on this.

[0053] In the related technology, in the BGP cross-domain scenario, the autonomous system boundary router ASBR announces the summary route instead of the detailed route between domains. However, for routers located in two different autonomous domains, if one of the links or routers fails and cannot receive any messages, the other router cannot detect the change in the reachability status of the destination in time and still sends messages, which will cause routing and traffic black holes.

[0054] When two routers across domains establish a BGP neighbor relationship, if they cannot detect the reachability status change of the other BGP neighbor in time, the BGP routing convergence rate will be greatly reduced.

[0055] The present disclosure can be applied to Figure 1When the R3-R1 link fails, the unreachable prefix address of the router R3 is sent to ASBR2, so that ASBR2 broadcasts the unreachable prefix address of R3 in AS2.

[0056] The present disclosure can also be applied to Figure 2 When the R3-R1 link and the R4-R1 link fail at the same time, the unreachable prefix addresses of R3 and R4 are sent to ASBR2, so that ASBR2 broadcasts the unreachable prefix addresses of R3 and R4 in AS2.

[0057] Based on this, the solution provided in the embodiment of the present application involves communication and other technologies, and is a software program applied to a computer. The present invention obtains information related to unreachable prefix announcement from a received first unreachable prefix announcement message based on the internal gateway protocol IGP running in the first autonomous domain where the first autonomous system border router is located, and the information related to the unreachable prefix announcement includes unreachable prefix information, a first identification value and a second identification value; generates a border gateway protocol BGP update message based on the information related to the unreachable prefix announcement, and the BGP update message includes information related to the unreachable prefix announcement; sends a BGP update message to the second autonomous system border router, so that the second autonomous system border router broadcasts the information related to the unreachable prefix announcement in the second autonomous domain where the second autonomous system border router is located. The present disclosure extends the BGP protocol, so that the first autonomous system border router can encapsulate the received unreachable prefix announcement related information in the BGP message, and the second autonomous system border router that receives the BGP message can completely restore the unreachable prefix announcement related information carried in the original data packet, so as to realize the cross-domain transmission of the unreachable prefix announcement information, and allow routers located in different autonomous systems to timely notify each other of the real-time status of the links in their respective autonomous systems. In a large cross-domain network, relevant personnel can be assisted in fault location when a fault occurs, the occurrence of routing and traffic black holes can be reduced, and the routing convergence efficiency can be improved. The following embodiments are specifically described:

[0058] The embodiment of the present disclosure provides a cross-autonomous domain announcement method, which can be executed by any system with computing processing capabilities, such as a first autonomous system border router, or a second autonomous system border router, or the first autonomous system border router and the second autonomous system border router interacting to achieve it.

[0059] Figure 3 FIG. 2 shows a flow chart of a method for announcing a message across autonomous domains provided by an embodiment of the present disclosure. Figure 3 As shown, the cross-autonomous domain announcement method provided by the embodiment of the present disclosure is applied to a first autonomous system border router, wherein the method comprises the following steps:

[0060] S302. Obtain unreachable prefix advertisement related information from a received first unreachable prefix advertisement message according to the IGP running in the first autonomous domain where the first autonomous system border router is located. The unreachable prefix advertisement related information includes unreachable prefix information, a first identification value, and a second identification value.

[0061] In one embodiment, when a router or link in the first autonomous domain fails, a router interacting with the first autonomous system border router sends a first unreachable prefix advertisement message to the first autonomous system border router to inform the first autonomous system border router of unreachable prefix information in the first autonomous domain. For example, Figure 1 or Figure 2 The router R1 in the process sends a first unreachable prefix advertisement message to the first autonomous system border router ASBR1.

[0062] In the present disclosure, when the first autonomous system border router receives the first unreachable prefix advertisement message, it obtains the unreachable prefix advertisement related information in a designated field according to the IGP running in the first autonomous domain.

[0063] In one embodiment, the unreachable prefix announcement related message also includes a first identification value and a second identification value. In the first unreachable prefix announcement message, the first autonomous system border router can obtain the first identification value U-Flag and the second identification value UP-Flag from the IS-IS Bit Values ​​for Predix Attribute Flags Sub-TLV field of the prefix attribute flag.

[0064] The first identification value and the second identification value are used to characterize the reason for unreachability. The first identification value and the second identification value are the unreachable prefix notification information in the original message, which can ensure the integrity of the unreachable prefix notification information in the original message during cross-domain transmission.

[0065] The first autonomous system border router can obtain the unreachable prefix from the first unreachable prefix advertisement message, and the unreachable prefix information can be represented by an unreachable prefix list, which is used to record at least one unreachable prefix address in the first autonomous domain. Figure 1 The unreachable prefix address IP3 corresponding to R3 or Figure 2 The unreachable prefix addresses IP3 and IP4 corresponding to R3 and R4.

[0066] S304. Generate a BGP update message according to the unreachable prefix advertisement related information, wherein the BGP update message includes the unreachable prefix advertisement related information.

[0067] The BGP update message, also known as BGP UPDATE, includes a Multi-Protocol Unreachable Network Layer Reachability Information (MP_UNREACH_NLRI) field, where the MP_UNREACH_NLRI field includes an Address Family Identifier (AFI) field, a Subsequent Address Family Identifier (SAFI) field, and a Withdrawn Routes field.

[0068] The undo route field sets the first flag bit U, the second flag bit UP, the reserved field, the length field, and the unreachable prefix Unreachable Prefixes field. The message format of the MP_UNREACH_NLRI field is shown in Table 1.

[0069]

[0070] It should be noted that, in the MP_UNREACH_NLRI message format, when the SAFI field is a specific value, that is, when the value of the SAFI field is the specific value, the message format of the MP_UNREACH_NLRI is the format shown in Table 1.

[0071] When the first flag bit U is 1, it indicates that the first flag value of U-Flag in the original IGP message (or the first unreachable prefix notification message) is 1; when the second flag bit UP is 1, it indicates that the second flag value of UP-Flag in the original IGP message or the first unreachable prefix notification message is 1. If the values ​​of the first flag bit U and the second flag bit UP are both 1 or 0, the receiving device needs to discard the data packet. The Length field indicates the length of the unreachable prefix field.

[0072] In one embodiment, the above-mentioned S304 generates a Border Gateway Protocol BGP update message based on the unreachable prefix announcement related information, including: setting the sub-address cluster identification field to the value corresponding to the unreachable prefix announcement type; setting the first identification bit to the first identification value; setting the second identification bit to the second identification value, the first identification value represents the unreachability caused by unplanned reasons, and the second identification value represents the unreachability caused by planned reasons; writing the unreachable prefix information into the unreachable prefix field.

[0073] When the unreachable prefix information includes multiple unreachable prefixes, the multiple unreachable prefixes can be written into the unreachable prefix field separately, and adjacent unreachable prefixes are connected by connectors such as ","; or multiple unreachable prefixes can be summarized according to preset rules to obtain summarized prefix information, and the summarized prefix information can be written into the unreachable prefix field.

[0074] It should be noted that the value and preset rules corresponding to the unreachable prefix notification type can be determined according to actual needs, and the present disclosure does not make specific limitations on this.

[0075] In one embodiment, the method further includes: determining a total length of unreachable prefixes according to unreachable prefix information, and writing the total length of the unreachable prefixes into a length field, wherein the unreachable prefix information includes at least one unreachable prefix.

[0076] S306: Send a BGP update message to the second autonomous system border router, so that the second autonomous system border router broadcasts the unreachable prefix announcement related information in the second autonomous domain where the second autonomous system border router is located.

[0077] In one embodiment, the IGPs run by the first autonomous domain and the second autonomous domain include at least one of the IS-IS protocol and the OSPF protocol.

[0078] In one embodiment, the first autonomous system border router sends a BGP update message to the second autonomous system border router according to the BGP protocol. The second autonomous system border router extracts the value of the first identification bit U, the value of the second identification bit UP, the value of the length field, and the value of the unreachable prefix field from the BGP update message to obtain the unreachable prefix information.

[0079] The second autonomous system border router generates a corresponding second unreachable prefix advertisement message according to the IGP protocol running in the second autonomous domain, and broadcasts the second unreachable prefix advertisement message in the second autonomous domain.

[0080] In an embodiment of the present disclosure, information related to an unreachable prefix announcement is obtained from a received first unreachable prefix announcement message according to an IGP running in a first autonomous domain where a first autonomous system border router is located, and the information related to the unreachable prefix announcement includes unreachable prefix information, a first identification value, and a second identification value; a Border Gateway Protocol BGP update message is generated according to the information related to the unreachable prefix announcement, and the BGP update message includes information related to the unreachable prefix announcement; and a BGP update message is sent to a second autonomous system border router, so that the second autonomous system border router broadcasts the information related to the unreachable prefix announcement in a second autonomous domain where the second autonomous system border router is located. The present disclosure extends the BGP protocol so that a first autonomous system border router can encapsulate the received unreachable prefix announcement related information in a BGP message, and a second autonomous system border router that receives the BGP message can completely restore the unreachable prefix announcement related information carried in the original data packet, so as to realize cross-domain transmission of the unreachable prefix announcement information, allow routers located in different autonomous systems to promptly notify each other of the real-time status of links within their respective autonomous systems, and in a large cross-domain network, assist relevant personnel in locating the fault when a fault occurs, reduce the occurrence of routing and traffic black holes, and improve routing convergence efficiency.

[0081] Based on the same inventive concept, the embodiment of the present disclosure also provides a first autonomous system border router, as described in the following embodiment. Since the principle of solving the problem in the router embodiment is similar to that in the above method embodiment, the implementation of the router embodiment can refer to the implementation of the above method embodiment, and the repeated parts will not be repeated.

[0082] Figure 4 FIG. 2 shows a schematic diagram of the structure of a first autonomous system border router provided by an embodiment of the present disclosure. Figure 4 As shown, the first autonomous system border router of this embodiment includes a first extraction module 410, a message generation module 420 and a message sending module 430; wherein:

[0083] A first extraction module 410 is used to obtain unreachable prefix announcement related information from a received first unreachable prefix announcement message according to an internal gateway protocol IGP running in a first autonomous domain where a first autonomous system border router is located, where the unreachable prefix announcement related information includes unreachable prefix information, a first identification value, and a second identification value;

[0084] A message generating module 420, configured to generate a Border Gateway Protocol BGP update message according to the unreachable prefix notification related information, wherein the BGP update message includes the unreachable prefix notification related information;

[0085] The message sending module 430 is configured to send a BGP update message to the second autonomous system border router, so that the second autonomous system border router broadcasts the unreachable prefix announcement related information in the second autonomous domain where the second autonomous system border router is located.

[0086] In one embodiment, the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a revoked route field; the revoked route field includes a first identification bit, a second identification bit and an unreachable prefix field; wherein the message generation module 420 is used to set the sub-address cluster identification field to a value corresponding to the unreachable prefix announcement type; set the first identification bit to a first identification value; set the second identification bit to a second identification value, the first identification value represents unreachable due to unplanned reasons, and the second identification value represents unreachable due to planned reasons; write the unreachable prefix information into the unreachable prefix field.

[0087] In an embodiment, the revocation route field also includes a length field; the message generation module 420 is also used to determine the total length of the unreachable prefixes based on the unreachable prefix information, and write the total length of the unreachable prefixes into the length field, wherein the unreachable prefix information includes at least one unreachable prefix.

[0088] It should be noted that the IGP running in the first autonomous domain and the second autonomous domain includes at least one of the IS-IS protocol and the OSPF protocol.

[0089] Figure 5 FIG. 2 is a schematic diagram showing the structure of another first autonomous system border router provided by an embodiment of the present disclosure. Figure 3 As shown, in one embodiment, the first autonomous system boundary router includes a memory 510 and a processor 520. The memory 510 is used to store executable instructions of the processor 520, the processor 520 is coupled to the memory 510, and the processor 520 is configured to execute the cross-autonomous domain announcement method in the above embodiment by executing the executable instructions.

[0090] like Figure 5 As shown, the first autonomous system border router also includes a communication interface 530, which is used to exchange information with other devices. The first autonomous system border router also includes a bus 540, through which the memory 510, the processor 520, and the communication interface 530 communicate with each other.

[0091] The memory 510 stores program codes, which can be executed by the processor 520, so that the processor 520 executes the steps of various exemplary embodiments of the present invention described in the above “Exemplary Method” section of this specification. For example, the processor 520 can execute the following steps: Figure 3As shown in the figure, the internal gateway protocol IGP running in the first autonomous domain where the first autonomous system border router is located obtains unreachable prefix announcement related information from the received first unreachable prefix announcement message, and the unreachable prefix announcement related information includes unreachable prefix information, a first identification value and a second identification value; generates a border gateway protocol BGP update message according to the unreachable prefix announcement related information, wherein the BGP update message includes the unreachable prefix announcement related information; sends the BGP update message to the second autonomous system border router, so that the second autonomous system border router broadcasts the unreachable prefix announcement related information in the second autonomous domain where the second autonomous system border router is located.

[0092] The memory 510 may include a readable medium in the form of a volatile storage unit, such as a random access memory (RAM) and / or a cache memory, and may further include a read-only memory (ROM).

[0093] Memory 510 may also include a program / utility having a set (at least one) of program modules, such program modules including but not limited to: an operating system, one or more application programs, other program modules, and a number of programs, each of which or some combination may include an implementation of a network environment.

[0094] The processor 520 may be a central processing unit, or may be an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present disclosure.

[0095] Bus 540 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0096] The first autonomous system border router can also communicate with one or more external devices (such as keyboards, pointing devices, Bluetooth devices, etc.), and can also communicate with one or more devices that enable users to interact with the router, and / or communicate with any device (such as routers, modems, etc.) that enables the router to communicate with one or more other computing devices. This communication can be carried out through an input / output (I / O) interface. In addition, the first autonomous system border router ASBR1 can also communicate with one or more networks (such as local area networks (LANs), wide area networks (WANs) and / or public networks, such as the Internet) through a network adapter. The network adapter communicates with other modules of the first autonomous system border router ASBR1 through bus 540. It should be understood that, although not shown in the figure, other hardware and / or software modules can be used in conjunction with the first autonomous system border router ASBR1, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and digital backup storage systems, etc.

[0097] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes a number of instructions to enable a computing device (which can be a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the implementation of the present disclosure.

[0098] Figure 6 FIG. 2 shows another flow chart of a cross-autonomous domain notification method provided by an embodiment of the present disclosure. Figure 6 As shown, in one embodiment, the cross-autonomous domain notification method of the embodiment of the present disclosure is applied to the second autonomous system border router, and the method mainly includes the following steps:

[0099] S602. Receive a BGP update message sent by the first autonomous system border router, where the BGP update message includes unreachable prefix announcement related information, where the unreachable prefix announcement related information is obtained by the first autonomous system border router from a first unreachable prefix announcement message received according to an IGP running in the first autonomous domain where the first autonomous system border router is located, and the unreachable prefix announcement related information includes unreachable prefix information, a first identification value, and a second identification value;

[0100] S604, extracting unreachable prefix notification related information from the BGP update message;

[0101] S606: Generate a second unreachable prefix advertisement message according to the internal gateway protocol IGP running in the second autonomous domain where the second autonomous system border router is located and the unreachable prefix advertisement related information, and broadcast the message in the second autonomous domain.

[0102] In one embodiment, the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a withdrawn route field; the withdrawn route field includes a first identification bit, a second identification bit and an unreachable prefix field.

[0103] In one embodiment, S604 extracts unreachable prefix announcement related information from a BGP update message, including: when the value of the sub-address cluster identification field extracted from the BGP update message is a value corresponding to the unreachable prefix announcement type, determining that the BGP update message is an unreachable prefix announcement type message; extracting the first identification bit, the second identification bit, and the value of the unreachable prefix field from the BGP update message to obtain a first identification value, a second identification value, and unreachable prefix information, wherein the first identification value indicates that the unreachability is caused by unplanned reasons, and the second identification value indicates that the unreachability is caused by planned reasons.

[0104] In one embodiment, the withdraw route field also includes a length field; the method also includes: extracting a value of the length field from the BGP update message to determine the total length of the unreachable prefix, wherein the unreachable prefix information includes at least one unreachable prefix.

[0105] It should be noted that the IGP running in the first autonomous domain and the second autonomous domain includes at least one of the IS-IS protocol and the OSPF protocol.

[0106] It should be noted that when the value of the sub-address cluster identification field extracted from the BGP update message is a specific value, the BGP update message is determined to be an unreachable prefix announcement type message, and the unreachable prefix announcement related information is extracted. When the value of the sub-address cluster identification field extracted from the BGP update message is not a specific value, it is determined that the BGP update message is not an unreachable prefix announcement type message, and the unreachable prefix announcement related information is no longer extracted.

[0107] Based on the same inventive concept, the embodiment of the present disclosure also provides a second autonomous system border router, as described in the following embodiment. Since the principle of solving the problem in the router embodiment is similar to that in the above method embodiment, the implementation of the router embodiment can refer to the implementation of the above method embodiment, and the repeated parts will not be repeated.

[0108] Figure 7 FIG. 2 is a schematic diagram showing a structure of a second autonomous system border router provided by an embodiment of the present disclosure. Figure 7As shown, the second autonomous system border router of this embodiment includes a message receiving module 710, a second extraction module 720 and a message broadcasting module 730; wherein:

[0109] The message receiving module 710 is used to receive a BGP update message sent by the first autonomous system border router, where the BGP update message includes unreachable prefix announcement related information, where the unreachable prefix announcement related information is obtained by the first autonomous system border router from a first unreachable prefix announcement message received according to an IGP running in the first autonomous domain where the first autonomous system border router is located, where the unreachable prefix announcement related information includes unreachable prefix information, a first identification value, and a second identification value;

[0110] A second extraction module 720 is used to extract unreachable prefix announcement related information from the BGP update message;

[0111] The message broadcast module 730 is used to generate a second unreachable prefix advertisement message and broadcast it in the second autonomous domain according to the internal gateway protocol IGP running in the second autonomous domain where the second autonomous system border router is located and the unreachable prefix advertisement related information.

[0112] In one embodiment, the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a revoked route field; the revoked route field includes a first identification bit, a second identification bit and an unreachable prefix field, wherein the second extraction module 720 is used to determine that the BGP update message is an unreachable prefix announcement type message when the value of the sub-address cluster identification field extracted from the BGP update message is a value corresponding to the unreachable prefix announcement type; extract the first identification bit, the second identification bit and the value of the unreachable prefix field from the BGP update message to obtain a first identification value, a second identification value and unreachable prefix information, wherein the first identification value indicates that the unreachability is caused by unplanned reasons, and the second identification value indicates that the unreachability is caused by planned reasons.

[0113] In one embodiment, the revoke route field also includes a length field; the second extraction module 720 is further used to extract the value of the length field from the BGP update message to determine the total length of the unreachable prefix, wherein the unreachable prefix information includes at least one unreachable prefix.

[0114] It should be noted that the IGP running in the first autonomous domain and the second autonomous domain includes at least one of the IS-IS protocol and the OSPF protocol.

[0115] Figure 8 FIG. 2 shows a schematic diagram of the structure of another second autonomous system border router provided by an embodiment of the present disclosure. Figure 8As shown, the second autonomous system boundary router includes a memory 810 , a processor 820 , a communication interface 830 , and a bus 840 . Figure 8 and Figure 5 The difference is that in Figure 8 In the illustrated embodiment, the processor 820 is configured to execute instructions stored in the memory 810 to implement the following Figure 6 The method described in any embodiment of the present invention will not be repeated herein.

[0116] The present disclosure also provides a communication system. Figure 1-Figure 2 As shown, the communication system includes a first autonomous domain AS1 and a second autonomous domain AS2. The first autonomous domain AS1 is provided with a first autonomous system border router ASBR1, and the second autonomous domain AS2 is provided with a second autonomous border routing system ASBR2. Figure 4 or Figure 5 The first autonomous system border router involved in any embodiment, ASBR2 is Figure 7 or Figure 8 The second autonomous system border router involved in any embodiment.

[0117] like Figure 1 or Figure 2 As shown, after ASBR1 receives the first unreachable prefix announcement message sent by R1, it obtains the unreachable prefix announcement related information in the specified field of the first unreachable prefix announcement message according to the IGP protocol run by AS1. The unreachable prefix announcement related information includes but is not limited to the U-Flag value (i.e., the first identification value), the UP-Flag value (i.e., the second identification value), the unreachable prefix list (i.e., the unreachable prefix information), etc.

[0118] ASBR1 generates a BGP update message (also called a BGPUPDATE message) based on the obtained unreachable prefix advertisement related information. The value of the SAFI field of the attribute MP_UNREACH_NLRI of the BGP update message is the value corresponding to the unreachable prefix advertisement type. The value of the first identification bit U and the value of the second identification bit UP are set according to the first identification value U-Flag and the second identification value UP-Flag. The length field (Length) and the unreachable prefix field (Unreachable Predixes) are set according to the unreachable address prefix information carried in the first unreachable prefix advertisement message. The value of the length field is used to represent the length of the unreachable address list.

[0119] ASBR1 sends the generated BGP update message to ASBR2.

[0120] ASBR2 receives the BGP update message sent by ASBR1, and extracts the value of the U-Flag, the value of the UP-Flag, the value of the unreachable prefix list, and the value of the length field from the BGP update message.

[0121] ASBR2 generates a corresponding second unreachable prefix announcement message according to the IGP protocol running in the second autonomous domain AS2, and broadcasts the second unreachable prefix announcement message in the second autonomous domain AS2, so that each router in the second autonomous domain AS2 can promptly understand the real-time status of the link in the first autonomous domain AS1.

[0122] In order to deeply understand the cross-autonomous domain notification method provided by the embodiment of the present disclosure, Figure 1 or Figure 2 A specific example is given below to illustrate.

[0123] In Examples 1 to 4, ASBR1 is a first autonomous system border router, ASBR2 is a second autonomous system border router, AS1 is a first autonomous domain, and AS2 is a second autonomous domain.

[0124] Example 1: The IGP running in AS1 and AS2 is IS-IS

[0125] like Figure 1 As shown, service data is exchanged between R3 and T3. When the link between R3 and R1 is disconnected, R1 generates a first unreachable prefix announcement message (or IGP UPA message) and broadcasts it in AS1.

[0126] When ASBR1 receives the first unreachable prefix advertisement message sent by R1, it performs the following operations:

[0127] 1. ASBR1 checks whether the metric value in the first unreachable prefix notification message is greater than 0xFE000000. If so, ASBR1 obtains the first identification value U-Flag and the second identification value UP-Flag from the IS-IS Bit Values ​​for Prefix Attribute Flags Sub-TLV, and obtains the unreachable prefix from the message. The unreachable prefix here is R3's IP address IP3. Otherwise, the first identification value U-Flag and the second identification value UP-Flag are not obtained.

[0128] 2. ASBR1 generates a BGP update message (BGP UPDATE message) according to the obtained first identification value U-Flag, the second identification value UP-Flag and the unreachable prefix. The value of the SAFI field of the attribute MP_UNREACH_NLRI of the message is the value corresponding to the unreachable prefix announcement type. The values ​​of the first identification bit U and the second identification bit UP are set according to the first identification value U-Flag and the second identification value UP-Flag of the IGP unreachable prefix announcement message. The value of the Length field is the length of IP3, and the value of the Unreachable Prefixes field is IP3.

[0129] 3. ASBR1 sends the generated BGP UPDATE message to ASBR2.

[0130] When ASBR2 receives the BGP UPDATE message, it performs the following operations:

[0131] 1. ASBR2 learns that the message is a BGP unreachable prefix advertisement type message based on the value of the SAFI field in the attribute MP_UNREACH_NLRI of the BGP UPDATE message, which corresponds to the unreachable prefix advertisement type.

[0132] 2. ASBR2 obtains the value of the first identifier U, the value of the second identifier UP, the total length of the unreachable prefixes, and the unreachable prefix list from the BGP UPDATE message.

[0133] 3. ASBR2 generates an IS-IS data packet. The values ​​of U-Flag and UP-Flag in the IS-IS Bit Values ​​for PrefixAttribute Flags Sub-TLV of the IS-IS data packet are set according to the values ​​of the first flag bit U and the second flag bit UP. The value of the unreachable prefix is ​​IP3. The metric value is set to a value greater than 0xFE000000.

[0134] 4. ASBR2 broadcasts the generated IS-IS data packet in AS2.

[0135] It should be noted that the values ​​of U-Flag and UP-Flag are set by R1 according to the reason why R3 is unreachable. When the U bit is 1, it means that R3 is unreachable due to unplanned reasons. When the UP bit is 1, it means that R3 is unreachable due to planned reasons (such as planned maintenance).

[0136] Example 2: The IGP running in AS1 and AS2 is OSPFv2

[0137] like Figure 1As shown, service data is exchanged between R3 and T3. When the link between R3 and R1 is disconnected, R1 generates a first unreachable prefix announcement message (or IGP UPA message) and broadcasts it in AS1.

[0138] When ASBR1 receives the first unreachable prefix advertisement message, it performs the following operations:

[0139] 1. ASBR1 first checks whether the metric value is equal to LSInfinity. If so, ASBR1 obtains the first identification value U-Flag and the second identification value UP-Flag from the Prefix AttributesSub-TLV, and obtains the unreachable prefix from the message. The unreachable prefix here is R3's IP address IP3. Otherwise, the first identification value U-Flag and the second identification value UP-Flag are not obtained.

[0140] 2. ASBR1 generates a BGPUPDATE message based on the first identification value U-Flag, the second identification value UP-Flag and the unreachable prefix. The value of the SAFI field of the attribute MP_UNREACH_NLRI of the message is the value corresponding to the unreachable prefix notification type. The values ​​of the first identification bit U and the second identification bit UP are set according to the first identification value U-Flag and the second identification value UP-Flag in the first unreachable prefix notification message. The value of the Length field is the length of IP3, and the value of the UnreachablePrefixes field is IP3.

[0141] 3. ASBR1 sends the generated BGP UPDATE message to ASBR2.

[0142] When ASBR2 receives the BGP UPDATE message, it performs the following operations:

[0143] 1. ASBR2 learns that the message is a BGP unreachable prefix advertisement type message based on the value of the SAFI field in the attribute MP_UNREACH_NLRI of the BGP UPDATE message, which corresponds to the unreachable prefix advertisement type.

[0144] 2. ASBR2 obtains the value of the first identification bit U, the value of the second identification bit UP, the total length of the unreachable prefixes, and the unreachable prefix list from the BGP UPDATE message.

[0145] 3. ASBR2 generates an OSPFv2 data packet. The values ​​of U-Flag and UP-Flag in the Prefix Attributes Sub-TLV of the data packet are set according to the values ​​of the first identification bit U and the second identification bit UP. The value of the unreachable prefix is ​​IP3. The metric value is set to LSInfinity.

[0146] 4. ASBR2 broadcasts the generated OSPFv2 data packet in AS2.

[0147] Example 3: The IGP running in AS1 and AS2 is OSPFv3

[0148] like Figure 1 As shown, service data is exchanged between R3 and T3. When the link between R3 and R1 is disconnected, R1 generates a first unreachable prefix announcement message (or IGP UPA message) and broadcasts it in AS1.

[0149] When ASBR1 receives the first unreachable prefix advertisement message, it performs the following operations:

[0150] 1. ASBR1 first checks whether the metric value is equal to LSInfinity and the NU bit value in PrefixOptions is 1. If so, ASBR1 obtains the first identification value U-Flag and the second identification value UP-Flag from the Prefix Attributes Sub-TLV, and obtains the unreachable prefix from the message. The unreachable prefix here is R3's IP address IP3. Otherwise, the first identification value U-Flag and the second identification value UP-Flag are not obtained.

[0151] 2. ASBR1 generates a BGPUPDATE message according to the first identification value U-Flag, the second identification value UP-Flag, and the unreachable prefix. The value of the SAFI field of the attribute MP_UNREACH_NLRI of the message is the value corresponding to the unreachable prefix notification type. The values ​​of the first identification bit U and the second identification bit UP are set according to the first identification value U-Flag and the second identification value UP-Flag in the first unreachable prefix notification message. The value of the Length field is the length of IP3, and the value of the UnreachablePrefixes field is IP3.

[0152] 3. ASBR1 sends the generated BGP UPDATE message to ASBR2.

[0153] When ASBR2 receives the BGP UPDATE message, it performs the following operations:

[0154] 1. ASBR2 knows that the message is of the unreachable prefix advertisement type based on the value of the SAFI field in the attribute MP_UNREACH_NLRI of the message, which corresponds to the unreachable prefix advertisement type.

[0155] 2. ASBR2 obtains the value of the first identification bit U, the value of the second identification bit UP, the total length of the unreachable prefixes, and the unreachable prefix list from the BGP UPDATE message.

[0156] 3. ASBR2 generates an OSPFv3 packet. The NU bit value in the PrefixOptions of the packet is set to 1. The values ​​of U-Flag and UP-Flag in the Prefix Attributes Sub-TLV are set according to the values ​​of the first identification bit U and the second identification bit UP. The value of the unreachable prefix is ​​IP3. The metric value is set to LSInfinity.

[0157] 4. ASBR2 broadcasts the generated OSPFv3 data packet in AS2.

[0158] Example 4: The IGP protocol running in AS1 and AS2 is IS-IS, and there are multiple unreachable prefixes

[0159] like Figure 2 As shown, service data is exchanged between R3, R4 and T3. When the links between R3, R4 and R1 are disconnected, R1 generates a first unreachable prefix announcement message (or IGP UPA message) and broadcasts it in AS1.

[0160] When ASBR1 receives the first unreachable prefix advertisement message, it performs the following operations:

[0161] 1. ASBR1 first checks whether the metric value is greater than 0xFE000000. If so, ASBR1 obtains the first identification value U-Flag and the second identification value UP-Flag from the IS-IS BitValues ​​for Prefix Attribute Flags Sub-TLV, and obtains the unreachable prefix from the message. The unreachable prefix here is the IP addresses IP3 and IP4 of R3 and R4. Otherwise, the first identification value U-Flag and the second identification value UP-Flag are not obtained.

[0162] 2. ASBR1 generates a BGPUPDATE message according to the first identification value U-Flag, the second identification value UP-Flag and multiple unreachable prefixes. The value of the SAFI field of the attribute MP_UNREACH_NLRI of the message is the value corresponding to the unreachable prefix notification type. The values ​​of the first identification bit U and the second identification bit UP are set according to the first identification value U-Flag and the second identification value UP-Flag in the first unreachable prefix notification message. The value of the Length field is the sum of the lengths of IP3 and IP4. The value of the Unreachable Prefixes field is IP3 and IP4.

[0163] 3. ASBR1 sends the generated BGP UPDATE message to ASBR2.

[0164] When ASBR2 receives the BGP UPDATE message, it performs the following operations:

[0165] 1. ASBR2 learns that the message is of the unreachable prefix advertisement type based on the value of the SAFI field in the attribute MP_UNREACH_NLRI of the BGP UPDATE message, which corresponds to the unreachable prefix advertisement type.

[0166] 2. ASBR2 obtains the value of the first identification bit U, the value of the second identification bit UP, the total length of the unreachable prefixes, and the unreachable prefix list from the BGP UPDATE message.

[0167] 3. ASBR2 generates an IS-IS data packet. The values ​​of U-Flag and UP-Flag in the IS-IS Bit Values ​​for PrefixAttribute Flags Sub-TLV of the data packet are set according to the values ​​of the first identification bit U and the second identification bit UP. The values ​​of the unreachable prefix are IP3 and IP4. The metric value is set to a value greater than 0xFE000000.

[0168] 4. ASBR2 broadcasts the generated IS-IS data packet in AS2.

[0169] By implementing the present disclosure, the following beneficial effects can be obtained:

[0170] 1. The mechanisms of the existing IGP and BGP protocols are not modified. Only the existing protocol fields and attributes of the IGP and BGP protocols are used for extension.

[0171] 2. The present invention extends the BGP protocol so that the first autonomous system border router can encapsulate the received first unreachable prefix announcement information in a BGP message, and enables the second autonomous system border router to completely restore the unreachable prefix announcement information carried in the original data packet, so as to realize cross-domain transmission of the unreachable prefix announcement information, and allow routers located in different autonomous systems to promptly notify each other of the real-time status of the links within each autonomous system.

[0172] 3. By implementing the embodiments of the present disclosure, in a large cross-domain network, when a fault occurs, it can assist relevant personnel in locating the fault, reduce the occurrence of routing and traffic black holes, and improve routing convergence efficiency.

[0173] It will be appreciated by those skilled in the art that various aspects of the present invention may be implemented as a system, method or program product. Therefore, various aspects of the present invention may be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software, which may be collectively referred to herein as a "circuit", "module" or "system".

[0174] In particular, according to an embodiment of the present disclosure, the process described with reference to the flowchart above may be implemented as a computer program product, which includes: a computer program, which implements the above cross-autonomous domain notification method when executed by a processor.

[0175] In an exemplary embodiment of the present disclosure, a computer-readable storage medium is further provided, on which a program product capable of implementing the above method of the present specification is stored. Fig. 9 A schematic diagram of a computer-readable storage medium 900 provided by an embodiment of the present disclosure is shown. Fig. 9 As shown, a program product capable of implementing the above method of the present disclosure is stored on the computer-readable storage medium 900. In some possible implementations, various aspects of the present disclosure may also be implemented in the form of a program product, which includes a program code. When the program product is run on a terminal device, the program code is used to enable the terminal device to execute the steps according to various exemplary implementations of the present disclosure described in the above “Exemplary Method” section of this specification.

[0176] A program product for implementing the above method according to an embodiment of the present invention is described, which can adopt a portable compact disk read-only memory (CD-ROM) and include program code, and can be run on a terminal device, such as a personal computer. However, the program product of the present invention is not limited thereto, and in this document, a readable storage medium can be any tangible medium containing or storing a program, which can be used by or in combination with an instruction execution system, an apparatus or a device.

[0177] The program product may be any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination thereof. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0178] Computer readable signal media may include digital signals propagated in baseband or as part of a carrier wave, wherein readable program codes are carried. Such propagated digital signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Readable signal media may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device.

[0179] The program code embodied on the readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the foregoing.

[0180] Program code for performing the operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0181] It should be noted that, although several modules or units of the device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into multiple modules or units to be embodied.

[0182] In addition, although the steps of the method in the present disclosure are described in a specific order in the drawings, this does not require or imply that the steps must be performed in this specific order, or that all the steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps, etc.

[0183] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by combining software with necessary hardware. Therefore, the technical solution according to the implementation of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, a mobile terminal, or a network device, etc.) to execute the method according to the implementation of the present disclosure.

[0184] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. A cross-autonomous domain notification method, characterized in that: Applied to a first autonomous system border router; the method comprises: Obtaining unreachable prefix advertisement related information from a received first unreachable prefix advertisement message according to an internal gateway protocol IGP running in a first autonomous domain where the first autonomous system border router is located, wherein the unreachable prefix advertisement related information includes unreachable prefix information, a first identification value, and a second identification value; Generate a Border Gateway Protocol BGP update message according to the unreachable prefix announcement related information, wherein the BGP update message includes the unreachable prefix announcement related information; Sending the BGP update message to the second autonomous system border router so that the second autonomous system border router broadcasts the unreachable prefix notification related information in the second autonomous domain where the second autonomous system border router is located; the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a withdrawal route field; the withdrawal route field includes a first identification bit, a second identification bit and an unreachable prefix field; The step of generating a Border Gateway Protocol (BGP) update message according to the unreachable prefix notification related information includes: Setting the sub-address cluster identification field to a value corresponding to the unreachable prefix notification type; The first identification bit is set to a first identification value; the second identification bit is set to a second identification value, the first identification value indicates that the unreachable device is caused by an unplanned reason, and the second identification value indicates that the unreachable device is caused by a planned reason; The unreachable prefix information is written into the unreachable prefix field.

2. The method according to claim 1, characterized in that The withdraw route field also includes a length field; The method further comprises: The total length of the unreachable prefixes is determined according to the unreachable prefix information, and the total length of the unreachable prefixes is written into the length field, wherein the unreachable prefix information includes at least one unreachable prefix.

3. The method according to claim 1, characterized in that The internal gateway protocol IGP run by the first autonomous domain and the second autonomous domain includes at least one of the IS-IS protocol and the OSPF protocol.

4. A first autonomous system border router, characterized in that: include: A first extraction module is used to obtain unreachable prefix announcement related information from a received first unreachable prefix announcement message according to an internal gateway protocol IGP running in a first autonomous domain where the first autonomous system border router is located, wherein the unreachable prefix announcement related information includes unreachable prefix information, a first identification value, and a second identification value; A message generating module, configured to generate a Border Gateway Protocol (BGP) update message according to the unreachable prefix notification related information, wherein the BGP update message includes the unreachable prefix notification related information; A message sending module, configured to send the BGP update message to the second autonomous system border router, so that the second autonomous system border router broadcasts the unreachable prefix notification related information in the second autonomous domain where the second autonomous system border router is located; the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a revoked route field; the revoked route field includes a first identification bit, a second identification bit and an unreachable prefix field; The message generation module is used to set the sub-address cluster identification field to a value corresponding to the unreachable prefix notification type; set the first identification bit to a first identification value; set the second identification bit to a second identification value, wherein the first identification value indicates that the unreachability is caused by unplanned reasons, and the second identification value indicates that the unreachability is caused by planned reasons; and write the unreachable prefix information into the unreachable prefix field.

5. A first autonomous system border router, characterized in that: include: processor; as well as A memory, configured to store executable instructions of the processor; The processor is configured to execute the cross-autonomous domain notification method as described in any one of claims 1-3 by executing the executable instructions.

6. A cross-autonomous domain notification method, characterized in that: Applied to a second autonomous system border router; the method comprises: Receive a BGP update message sent by a first autonomous system border router, where the BGP update message includes information related to an unreachable prefix announcement, where the information related to the unreachable prefix announcement is obtained by the first autonomous system border router from a received first unreachable prefix announcement message according to an internal gateway protocol IGP running in a first autonomous domain where the first autonomous system border router is located, and the information related to the unreachable prefix announcement includes unreachable prefix information, a first identification value, and a second identification value; Extracting the unreachable prefix announcement related information from the BGP update message; According to the internal gateway protocol IGP running in the second autonomous domain where the second autonomous system border router is located and the unreachable prefix announcement related information, a second unreachable prefix announcement message is generated and broadcasted in the second autonomous domain; the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a withdrawal route field; the withdrawal route field includes a first identification bit, a second identification bit and an unreachable prefix field; The extracting the unreachable prefix announcement related information from the BGP update message includes: When the value of the sub-address cluster identification field extracted from the BGP update message is a value corresponding to the unreachable prefix advertisement type, determining that the BGP update message is a message of the unreachable prefix advertisement type; The first identification bit, the second identification bit and the value of the unreachable prefix field are extracted from the BGP update message to obtain a first identification value, a second identification value and the unreachable prefix information, wherein the first identification value indicates that the unreachability is caused by unplanned reasons, and the second identification value indicates that the unreachability is caused by planned reasons.

7. The method according to claim 6, characterized in that The withdraw route field also includes a length field; The method further comprises: The value of the length field is extracted from the BGP update message to determine the total length of the unreachable prefix, wherein the unreachable prefix information includes at least one unreachable prefix.

8. The method according to claim 6, characterized in that The internal gateway protocol IGP run by the first autonomous domain and the second autonomous domain includes at least one of the IS-IS protocol and the OSPF protocol.

9. A second autonomous system border router, characterized in that: include: a message receiving module, configured to receive a BGP update message sent by a first autonomous system border router, wherein the BGP update message includes information related to an unreachable prefix announcement, wherein the information related to the unreachable prefix announcement is obtained by the first autonomous system border router from a first unreachable prefix announcement message received according to an internal gateway protocol IGP running in a first autonomous domain where the first autonomous system border router is located, and wherein the information related to the unreachable prefix announcement includes unreachable prefix information, a first identification value, and a second identification value; A second extraction module is used to extract the unreachable prefix announcement related information from the BGP update message; A message broadcast module, configured to generate a second unreachable prefix announcement message and broadcast it in the second autonomous domain according to the internal gateway protocol IGP running in the second autonomous domain where the second autonomous system border router is located and the unreachable prefix announcement related information; the multi-protocol unreachable network layer reachability information field of the BGP update message includes a sub-address cluster identification field and a revoked route field; the revoked route field includes a first identification bit, a second identification bit and an unreachable prefix field; The second extraction module is further used to determine that the BGP update message is a message of the unreachable prefix announcement type when the value of the sub-address cluster identification field extracted from the BGP update message is a value corresponding to the unreachable prefix announcement type; The first identification bit, the second identification bit and the value of the unreachable prefix field are extracted from the BGP update message to obtain a first identification value, a second identification value and the unreachable prefix information, wherein the first identification value indicates that the unreachability is caused by unplanned reasons, and the second identification value indicates that the unreachability is caused by planned reasons.

10. A second autonomous system border router, characterized in that: include: processor; and a memory for storing executable instructions for the processor; The processor is configured to execute the cross-autonomous domain notification method as described in any one of claims 6 to 8 by executing the executable instructions.

11. A communication system, characterized in that: include: A first autonomous domain, wherein the first autonomous domain is provided with the first autonomous system border router as claimed in claim 4; A second autonomous domain, wherein the second autonomous system border router as claimed in claim 9 is provided in the second autonomous domain.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it implements the cross-autonomous domain notification method as described in any one of claims 1-3, or implements the cross-autonomous domain notification method as described in any one of claims 6-8.

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