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EP-4740403-A1 - OVERLAY-BASED OAM FOR BGP FAULT DETECTION

EP4740403A1EP 4740403 A1EP4740403 A1EP 4740403A1EP-4740403-A1

Abstract

Techniques for generating and utilizing overlay-based Border Gateway Protocol (BGP) Operations, Administration, and Maintenance (OAM) packets to detect issues with an underlay network. The techniques may include receiving, from a BGP peer device via a control plane path, an OAM probe indicating a forwarding path to be used for sending the traffic to a destination associated with a prefix. The techniques may also include determining, based at least in part on the OAM probe, that a next-hop device is incapable of being utilized to forward the traffic to the destination, the next-hop device determined based on an origination of the prefix. The techniques may further include performing a policy-based action based at least in part on determining that the next-hop device is incapable of being utilized to forward the traffic to the destination.

Inventors

  • MISHRA, Mankamana, Prasad
  • KRATTIGER, LUKAS
  • BROCKNERS, FRANK
  • KUMAR, NITIN

Assignees

  • Cisco Technology, Inc.

Dates

Publication Date
20260513
Application Date
20240702

Claims (20)

  1. 1. A method performed at least partially by a Border Gateway Protocol (BGP) router, the method comprising: storing, in a control plane forwarding table, an identifier associated with a next-hop device that is capable of being utilized by the BGP router to forward traffic to a destination associated with a prefix; receiving, from a BGP peer device via a control plane path, an Operations, Administration, and Maintenance (OAM) probe indicating a forwarding path to be used for sending the traffic to the destination; determining, based at least in part on the OAM probe, that the next-hop device is incapable of being utilized to forward the traffic to the destination; and performing a policy -based action based at least in part on determining that the next-hop device is incapable of being utilized to forw ard the traffic to the destination.
  2. 2. The method of claim 1, wherein the OAM probe was (i) originated by a BGP source router advertising the prefix and (ii) software forwarded to the BGP router along the control plane path.
  3. 3. The method of claim 2, wherein the BGP peer device is one of multiple BGP peer devices disposed along the control plane path between the BGP source router and the BGP router, each one of the multiple BGP peer devices configured to forward the OAM probe from the BGP source router to the BGP router.
  4. 4. The method of any of claims 1 to 3, wherein the policy-based action comprises at least one of causing the BGP peer device to redistribute routes associated with the prefix or updating the control plane forwarding table to remove the identifier associated with the nexthop device for the prefix.
  5. 5. The method of any of claims 1 to 4, wherein the BGP peer device is at least one of a route reflector or another BGP router and the next-hop device is distinguishable from the BGP peer device.
  6. 6. The method of any of claims 1 to 5, further comprising originating, by the BGP router, a new OAM probe that is to be sent in a reverse direction along the control plane path to a BGP source router that originated the prefix.
  7. 7. The method of any of claims 1 to 6, wherein the BGP router is a first BGP router, the next-hop device is second BGP router, and the second BGP router is incapable of being utilized to forward the traffic to the destination based at least in part on a network change between the second BGP router and a third BGP router, the first BGP router and the second BGP router associated with a first autonomous system and the third BGP router associated with a second autonomous system.
  8. 8. The method of any of claims 1 to 7, wherein the OAM probe is an overlay OAM probe and determining that the next-hop device is incapable of being utilized to forward the traffic to the destination comprises: receiving, via a data plane path, an underlay OAM probe that is distinguishable from the overlay OAM probe; and determining, based at least in part on the overlay OAM probe and the underlay OAM probe, a discrepancy betw een the forw arding path and an advertised path for sending the traffic to the destination, the advertised path determined based on an origination of the prefix.
  9. 9. A system associated with a Border Gateway Protocol (BGP) router, the system comprising: one or more processors; and one or more non-transitory computer-readable media storing instructions that, when executed, cause the one or more processors to perform operations comprising: storing, in a control plane forwarding table, an identifier associated with a next-hop device that is capable of being utilized by the BGP router to forw ard traffic to a destination associated with a prefix; receiving, from a BGP peer device via a control plane path, an Operations, Administration, and Maintenance (OAM) probe indicating a forwarding path to be used for sending the traffic to the destination; determining, based at least in part on the OAM probe, that the next-hop device is incapable of being utilized to forward the traffic to the destination; and performing a policy -based action based at least in part on determining that the next-hop device is incapable of being utilized to forward the traffic to the destination.
  10. 10. The system of claim 9, wherein the 0 AM probe was (i) originated by a BGP source router advertising the prefix and (ii) software forwarded to the BGP router along the control plane path.
  11. 1 1 . The system of claim 10, wherein the BGP peer device is one of multiple BGP peer devices disposed along the control plane path between the BGP source router and the BGP router, each one of the multiple BGP peer devices configured to forward the 0 AM probe from the BGP source router to the BGP router.
  12. 12. The system of any of claims 9 to 11, wherein the policy -based action comprises at least one of causing the BGP peer device to redistribute routes associated with the prefix or updating the control plane forwarding table to remove the identifier associated with the nexthop device for the prefix.
  13. 13. The system of any of claims 9 to 12, wherein the BGP peer device is at least one of a route reflector or another BGP router and the next-hop device is distinguishable from the BGP peer device.
  14. 14. The system of any of claims 9 to 13, the operations further comprising originating, by the BGP router, a new' 0AM probe that is to be sent in a reverse direction along the control plane path to a BGP source router that originated the prefix.
  15. 15. The system of any of claims 9 to 14, wherein the BGP router is a first BGP router, the next-hop device is second BGP router, and the second BGP router is incapable of being utilized to forward the traffic to the destination based at least in part on a network change between the second BGP router and a third BGP router, the first BGP router and the second BGP router associated with a first autonomous system and the third BGP router associated with a second autonomous system.
  16. 16. The system of any of claims 9 to 15, wherein the OAM probe is an overlay 0AM probe and determining that the next-hop device is incapable of being utilized to forward the traffic to the destination comprises: receiving, via a data plane path, an underlay OAM probe that is distinguishable from the overlay OAM probe; and determining, based at least in part on the overlay OAM probe and the underlay OAM probe, a discrepancy between the forwarding path and an advertised path for sending the traffic to the destination, the advertised path determined based on an origination of the prefix.
  17. 17. One or more non-transitory computer-readable media storing instructions that, when executed, cause one or more computing devices to perform operations comprising: storing, in a control plane forwarding table, an identifier associated with a next-hop device that is capable of being utilized by a Border Gateway Protocol (BGP) router to forw ard traffic to a destination associated with a prefix; receiving, from a BGP peer device via a control plane path, an Operations, Administration, and Maintenance (OAM) probe indicating a forwarding path to be used for sending the traffic to the destination; determining, based at least in part on the OAM probe, that the next-hop device is incapable of being utilized to forward the traffic to the destination; and performing a policy -based action based at least in part on determining that the next-hop device is incapable of being utilized to forward the traffic to the destination.
  18. 18. The one or more non-transitory computer-readable media of claim 17, wherein the OAM probe was (i) originated by a BGP source router advertising the prefix and (ii) software forwarded to the BGP router along the control plane path.
  19. 19. The one or more non-transitory computer-readable media of claim 18, wherein the BGP peer device is one of multiple BGP peer devices disposed along the control plane path between the BGP source router and the BGP router, each one of the multiple BGP peer devices configured to forward the OAM probe from the BGP source router to the BGP router.
  20. 20. The one or more non-transitory computer-readable media of any of claims 17 to 19, wherein the policy-based action comprises at least one of causing the BGP peer device to redistribute routes associated with the prefix or updating the control plane forw arding table to remove the identifier associated with the next-hop device for the prefix.

Description

OVERLAY-BASED 0AM FOR BGP FAULT DETECTION RELATED CASES [0001] This application claims priority to United States Non-Provisional Application Number 18/372,443 filed September 25, 2023; and United States Provisional Application Number 63/525,238 filed on July 6, 2023, the entire contents of which is incorporated herein by reference in its entirety and for all purposes. TECHNICAL FIELD [0002] The present disclosure relates generally to techniques for, among other things, the generation and utilization of overlay Border Gateway Protocol (BGP) Operations, Administration, and Maintenance (0AM) packets, which are forwarded between BGP peers via a control plane path, to determine if there are issues with an underlay network. BACKGROUND [0003] Border Gateway Protocol (BGP) is a crucial routing protocol used in the Internet and large-scale computer networks, as well as one of the primary protocols used in service provider networks and data centers. BGP enables communication and data exchange between network domains operated by different organizations or Internet Service Providers (ISPs) and plays a fundamental role in ensuring that data packets reach their intended destinations efficiently and securely. The primary function of BGP is to exchange routing information between routers in different network domains and determine the best path for data packets to traverse across multiple netw orks to reach their destination. When multiple paths to a destination are available, BGP uses a set of criteria, known as the BGP best path selection algorithm, to determine the optimal route based on factors like path length and other attnbutes. [0004] In recent years, however, studies have shown various scenarios in which BGP has led to outages. Of these scenarios, one of the most problematic cases leading to outages is when a BGP peer w ithdraw s a route and the route is not actually cleared (e.g., due to an internal software bug). As such, the route is still pointing to an incorrect next hop and these cases can lead to traffic outages for a whole prefix in a region. BRIEF DESCRIPTION OF THE DRAWINGS [0005] The detailed description is set forth below with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items. The systems depicted in the accompanying figures are not to scale and components within the figures may be depicted not to scale with each other. [0006] FIG. 1 is a system diagram illustrating an example architecture which may utilize various aspects of the techniques disclosed herein. [0007] FIG. 2 is a pictorial flow diagram illustrating an example process associated with the techniques described herein. [0008] FIG. 3 is a pictorial flow' diagram illustrating an example workflow associated with processing a BGP 0AM packet according to the techniques described herein. [0009] FIG. 4 is a flow diagram illustrating an example method associated with the techniques described herein. [0010] FIG. 5 is a block diagram illustrating an example packet switching system that can be utilized to implement various aspects of the technologies disclosed herein. [0011] FIG. 6 is a block diagram illustrating certain components of an example node that can be utilized to implement various aspects of the technologies disclosed herein. [0012] FIG. 7 is a computer architecture diagram showing an illustrative computer hardware architecture for implementing a computing device that can be utilized to implement aspects of the various technologies presented herein. DESCRIPTION OF EXAMPLE EMBODIMENTS OVERVIEW [0013] Aspects of the invention are set out in the independent claims and preferred features are set out in the dependent claims. Features of one aspect may be applied to each aspect alone or in combination with other features. [0014] This application is directed to techniques for generating and utilizing overlay BGP 0AM packets, which are forwarded between BGP peers via a control plane path, to determine if there are issues with an underlay network. By way of example, and not limitation, the techniques disclosed herein may include storing, in a control plane forwarding table associated with a BGP router, an identifier associated with a next-hop device that is capable of being utilized by the BGP router to forward traffic to a destination associated with a prefix. In some examples, the techniques may also include receiving, from a BGP peer device via a control plane path, an OAM probe indicating a forwarding path to be used for sending the traffic to the destination. Based at least in part on the OAM probe, a determination may be made that the next-hop device is incapable of being utilized to forward the traffic to the destination. The techniques may also include performing a policy-based action based at least in part on determining that the