Label-Switched Path Update Mechanism for Loop-Free MPLS Convergence
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Solution Overview
Problem
In MPLS networks, network disruptions due to component failures lead to packet drops and routing loops during convergence, as existing solutions either require administrator configuration or complex tunneling, and there is a lack of support for multi-topology routing, resulting in prolonged disruption and potential routing loops.
Innovation Solution
A method for updating label-switched paths involves an updating node receiving notification of a network change, constructing a post-change path, and after a calculated period, switching to the new path while retaining old information to prevent looping, ensuring all affected nodes update their forwarding tables to avoid loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If normal routing convergence is used after network component failure, then routing information eventually stabilizes, but traffic delivery is disrupted for too long
Solution Approach 1:
The patent pre-calculates and pre-signals repair paths using RSVP methods before network component failures occur. This preliminary preparation of alternative routing paths enables rapid switchover when failures happen, avoiding the need for time-consuming normal convergence procedures and thus maintaining traffic delivery continuity while minimizing convergence time.
2Reliability
If pre-computed repair paths using RSVP methods are used, then traffic delivery continuity is improved, but network administrator configuration complexity increases
Solution Approach 1:
The patent enables computing nodes to automatically compute and determine alternate next-hops without requiring network administrator configuration. The system self-service by autonomously calculating repair paths and updating forwarding information bases, thus maintaining traffic delivery continuity while eliminating the complexity of manual configuration.
3Reliability
If alternate next-hop redirection is implemented, then packet forwarding reliability improves, but the solution is limited to maximum two hops
Solution Approach 1:
The patent segments the routing update process into multiple epochs or phases, allowing progressive propagation of routing changes through the network. This segmentation enables the system to handle failures beyond two hops by breaking down the complex routing update into manageable stages, thus improving both packet forwarding reliability and routing flexibility simultaneously.
4Loss of time
If rapid path switching is implemented upon network change, then convergence time is reduced, but routing loops may occur during transition
Solution Approach 1:
The patent pre-calculates repair paths and pre-sigals routing information before actual network failures occur. This preliminary preparation ensures that when rapid path switching is needed, the alternative paths are already validated and ready, enabling fast convergence without creating routing loops during the transition phase.
Solution Approach 2:
The patent implements a feedback mechanism where computing nodes monitor network conditions and automatically adjust routing decisions based on real-time status. This feedback control ensures that rapid path switching occurs only when appropriate and safe, preventing routing loops while maintaining fast convergence.
Data Source
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AI summary
A method of updating a label switching path for forwarding data in a data communication network in response to a change in the network receiving notification of a network change (step 300), constructing new path (step 304), distributing new path (step 306) and switching to the new path after a predetermined time period (step 310).