Backup LSP for MPLS Double Failure Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
MPLS Fast Reroute systems do not provide adequate protection against double failures, leading to service disruption when both the primary and Bypass LSPs fail, as they only address single failure scenarios.
Innovation Solution
A method is introduced to establish a Backup Label Switched Path (LSP) for an existing Bypass LSP, using a network processor to generate a request for a disjoint path from the Point of Local Repair to the Merge Point, which can signal either a fully or partially disjoint path as a Backup LSP, depending on availability, to ensure continued service in case of dual failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If MPLS Fast Reroute uses a Bypass LSP to protect against single failures, then recovery speed is improved, but the system becomes vulnerable to double failures
Solution Approach 1:
The patent pre-establishes a Backup LSP path alongside the Bypass LSP before any failure occurs. This preliminary configuration ensures that when a failure happens, the system can immediately switch to the Backup LSP without needing to calculate a new path, thus maintaining fast recovery while adding protection against double failures.
Solution Approach 2:
The patent implements a standby protection mechanism that provides an additional layer of redundancy before double failures can occur. By having a Backup LSP ready in advance, the system cushions against the vulnerability of relying solely on a single Bypass LSP, ensuring service continuity even when the Bypass path fails.
2Reliability
If a Backup LSP is established for the Bypass LSP, then protection against double failures is improved, but device complexity increases
Solution Approach 1:
The patent merges the Backup LSP configuration with the existing Bypass LSP setup. Both paths share the same Point of Local Repair (PLR) and Merge Point (MP) endpoints, and the Backup LSP is established using the same path calculation methodology. This merging approach reduces operational complexity while providing enhanced protection.
Solution Approach 2:
The Backup LSP is designed to serve multiple protective functions: it protects against failures in the primary LSP, failures in the Bypass LSP, and can be configured to be disjoint from the Bypass path to handle shared risk scenarios. This multi-functionality reduces the need for separate protection mechanisms for each failure mode.
3Reliability
If a fully disjoint path is required for the Backup LSP, then protection effectiveness is improved, but path availability decreases
Solution Approach 1:
The patent implements a hierarchical approach where fully disjoint paths are preferred but not absolutely required. When a fully disjoint path is unavailable, the system accepts partially disjoint paths that still provide meaningful protection. This flexible approach ensures that protection is established whenever possible without being blocked by the unavailability of perfectly disjoint paths.
Solution Approach 2:
The path calculation process dynamically adjusts the disjointness requirement parameter based on network conditions. The system attempts to find fully disjoint paths first, but can relax the constraint to accept partially disjoint paths when necessary. This parameter adjustment allows the system to adapt to varying network topologies and availability conditions.
Data Source
AI summary
A method for providing a Backup Label Switched Path for a specified Bypass Label Switch Path is disclosed. The method for providing a Backup Label Switched Path for a specified Bypass Label Switch Path includes establishing a Bypass LSP having an end-to-end path; obtaining the nodes traversed by the end-to-end path; generating a request to a path calculator which using the nodes provided on the end-to-end path calculates a path disjoint to those nodes; and signaling the calculated disjoint path as a Backup LSP for the Bypass LSP. The method for providing a Backup Label Switched Path for a specified Bypass Label Switch Path provides protection advantages over systems known in the art by providing capability for handling double failure scenarios.