Micro-loop Avoidance via Temporary Tunnels
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Solution Overview
Problem
Current network technologies, such as MPLS, face challenges in minimizing traffic loss due to micro-loops caused by remote link failures during network convergence, as existing solutions like RFC 8333 only address local link failures and involve complex calculations.
Innovation Solution
The proposed solution involves creating a temporary tunnel using a Node Segment Identifier (SID) at the Point of Local Repair (PLR) to divert impacted traffic, leveraging existing loop-free backups, and implementing a delayed routing table update mechanism to ensure convergence without micro-loops, with separately configurable timers for remote nodes and PLR nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RFC 8333 is used for micro-loop avoidance, then local link failure micro-loops are prevented, but remote link failure micro-loops are not addressed
Solution Approach 1:
The patent pre-establishes backup paths and assigns Point of Local Repair (PLR) nodes before failures occur. When a remote link failure is detected, the PLR nodes that were pre-configured can immediately activate their backup paths without requiring complex real-time calculations, thus preventing micro-loops for both local and remote failures.
Solution Approach 2:
The patent introduces PLR nodes as intermediary elements that mediate between the failed link and the backup paths. These PLR nodes receive traffic that would otherwise create micro-loops and redirect it through pre-configured backup paths, extending micro-loop prevention coverage to remote link failures.
2Reliability
If complex P & Q space calculations are used to address remote link faults, then micro-loop prevention is achieved, but computational complexity increases
Solution Approach 1:
The patent performs complex path calculations and PLR assignments in advance during normal operation. When a failure occurs, the pre-computed backup paths are activated immediately without requiring real-time complex calculations, thus maintaining reliability while reducing operational complexity.
Solution Approach 2:
The patent uses simple, lightweight signaling mechanisms and temporary backup path activations rather than continuous complex calculations. The backup paths are activated only when needed (short-lived) and use minimal computational resources, reducing the complexity burden on network devices.
3Reliability
If temporary tunnels are installed for remote link failure, then traffic can be diverted in a loop-free manner, but network overhead increases
Solution Approach 1:
The patent pre-configures backup paths and PLR node assignments before failures occur. This preliminary setup reduces the overhead during actual failure events, as the temporary tunnels activate immediately using pre-computed information rather than requiring complex real-time tunnel establishment procedures.
Data Source
AI summary
Systems and methods for micro-loop avoidance include detecting a remote link failure in a network and identifying an associated Point of Local Repair (PLR); determining destinations in the network that are impacted due to the remote link failure; and installing of a temporary tunnel to the PLR. The steps can further include sending traffic destined for nodes impacted by the remote link failure via the temporary tunnel to the PLR. The temporary tunnel can be implemented by a node Segment Identifier (SID) for the PLR.