Loop-Free Routing Topology via Buttressing Arcs
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Solution Overview
Problem
Existing routing protocols face challenges in quickly responding to link failures without introducing loops, leading to data traffic loss due to computation time required for route recalculation, as seen in Loop Free Alternates (LFA) and Fast Local Rerouting for Handling Transient Link Failures (FIR).
Innovation Solution
The method involves creating a loop-free routing topology using routing arcs and buttressing arcs, where network devices exchange advertisement messages to form a distributed and ad-hoc loop-free routing topology, ensuring instantaneous rerouting without loops by reversing reversible links within the routing arcs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If route recalculation is performed in response to detected failure, then routing accuracy is improved, but response time deteriorates due to computation time required
Solution Approach 1:
The patent pre-calculates and stores multiple candidate paths (primary and secondary paths) before any failure occurs. When a link failure is detected, the system immediately switches to a pre-computed secondary path without performing real-time route recalculation, thus eliminating computation time delay while maintaining accurate routing.
Solution Approach 2:
The system prepares backup routing paths in advance as a cushion against potential failures. These pre-prepared alternative paths ensure that when a failure occurs, there is an immediate fallback option available, preventing service interruption and avoiding the need for time-consuming on-demand route recalculation.
2Speed
If Loop Free Alternates (LFA) is used to accelerate response to failure, then response speed is improved, but routing coverage deteriorates as LFA cannot provide solutions for certain network nodes
Solution Approach 1:
The patent creates a universal routing solution that works for all network nodes regardless of their position in the network topology. By establishing a hierarchical path structure with primary and secondary paths for every node-destination pair, the system achieves universal applicability that overcomes LFA's limitation of only working for certain nodes.
Solution Approach 2:
The routing path is segmented into primary path and secondary path components. This segmentation allows the system to provide specialized optimized paths for different scenarios: primary paths for normal operation and secondary paths for failure recovery, enabling the system to handle diverse routing scenarios across all network nodes.
3Speed
If Fast Local Rerouting for Handling Transient Link Failures (FIR) is implemented, then routing speed is improved, but route accuracy deteriorates due to complete recalculation requirement
Solution Approach 1:
The system performs preliminary route calculations and stores both primary and secondary paths before failures occur. This pre-computation ensures that when failures happen, the system can immediately switch to pre-validated secondary paths without performing complete recalculation, thus maintaining both speed and route accuracy.
Data Source
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AI summary
In one embodiment, a method comprises creating, in a computing network, a loop-free routing topology comprising a plurality of routing arcs for reaching a destination device, each routing arc routing any network traffic along the routing arc toward the destination device via any one of first or second ends of the corresponding routing arc, the creating including forming a buttressing arc having an originating end joined to a first of the routing arcs and a terminating end joined to a second of the routing arcs, the buttressing arc inheriting from the first routing arc a first height to the destination device, the first height of the first routing arc higher than a corresponding second height of the second routing arc; and causing the network traffic to be forwarded, to the destination device, via the buttressing arc and at least one of the first routing arc or the second routing arc.