MPLS Link Bundle Local Rerouting for Signaling Reduction
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Solution Overview
Problem
MPLS Traffic Engineering experiences significant signaling traffic and traffic disruption when a single component link fails, as existing rerouting mechanisms require extensive signaling and delay, especially when multiple LSPs are affected.
Innovation Solution
Implementing local rerouting by immediately substituting one or more other component links within the same link bundle at the point of failure without signaling to other nodes, minimizing signaling traffic and quickly restoring LSPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rerouting mechanisms are used when a component link fails, then LSPs can be rerouted to avoid the failed link, but signaling traffic increases significantly and traffic disruption increases
Solution Approach 1:
The patent pre-establishes backup paths and pre-configures rerouting parameters at nodes before a failure occurs. When a component link fails, nodes can immediately switch traffic to pre-prepared alternative paths without waiting for complex signaling procedures, thus reducing signaling traffic while maintaining reliable rerouting capability
Solution Approach 2:
The patent enables local nodes to autonomously detect failures and perform self-rerouting of LSPs without requiring extensive signaling to the head-end or other nodes. Each node maintains local state information about backup paths and can independently execute rerouting decisions, minimizing overall signaling traffic in the network
2Reliability
If head-end rerouting is performed for local repairs within link bundles, then LSPs can be rerouted around failed component links, but signaling traffic and delay increase
Solution Approach 1:
The patent pre-configures backup paths and rerouting parameters at intermediate nodes before failures occur. When a component link fails, nodes can immediately execute pre-prepared rerouting actions without waiting for head-end signaling, significantly reducing rerouting delay while maintaining reliable local repair capability
Solution Approach 2:
The patent enables different nodes to have different levels of awareness and control. Intermediate nodes maintain local state information about backup paths and can autonomously perform local repairs without requiring full network signaling, thus reducing delay while ensuring reliable rerouting
3Loss of time
If Fast Reroute is enabled for LSP protection, then recovery time is reduced, but signaling traffic and complexity increase
Solution Approach 1:
The patent pre-establishes backup paths and pre-configures Fast Reroute parameters at nodes before failures occur. When a component link fails, nodes can immediately switch traffic to pre-prepared backup paths without executing complex signaling procedures, thus achieving fast recovery with reduced signaling traffic and complexity
Solution Approach 2:
The patent enables nodes to autonomously detect failures and execute Fast Reroute actions locally without requiring extensive signaling to the head-end or other nodes. Each node maintains local state information about backup paths and can independently perform Fast Reroute, minimizing overall signaling complexity while maintaining fast recovery capability
Data Source
AI summary
Local rerouting around a failed component link of a link bundle is provided by immediately substituting one or more other component links of the same link bundle. The substitution of component links is performed at the point of failure without signaling to other nodes. This minimizes signaling traffic particularly when large numbers of LSPs are impacted by a single component link failure. Also, since LSP repair can be accomplished very quickly, traffic disruption is minimized.