Midspan LSP Re-optimization for MPLS Maintenance
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Solution Overview
Problem
Current MPLS protocols lack the ability to instantly influence label switched paths (LSPs) outside of network failure events, making it impractical to proactively re-optimize traffic for maintenance without significant delays or manual intervention across large networks.
Innovation Solution
Implementing mid-span re-optimization techniques that simulate a 'dummy' fast re-route event within the LSP path, allowing network operators to trigger path re-optimization by simulating link failures and re-routing traffic through existing protocols, enabling proactive and efficient re-routing without physical outages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If MPLS protocols are used to establish label switched paths, then packet forwarding becomes more efficient with less delay, but the ability to instantly influence LSPs outside of network failure events is lost
Solution Approach 1:
The patent implements preliminary action by pre-computing alternate paths and preparing re-optimization resources before network maintenance is needed. The system proactively identifies potential LSP optimizations and prepares alternative routing paths in advance, so that when maintenance windows open, traffic can be rapidly switched without waiting for reactive protocol signaling during the actual maintenance event.
Solution Approach 2:
The patent introduces an intermediary mechanism that sits between the control plane and data plane to enable rapid LSP modification. This intermediary component allows operators to trigger re-optimization events that bypass the normal slow MPLS signaling process, enabling instant influence on LSPs by mediating between traditional MPLS protocols and modern rapid rerouting requirements.
2Reliability
If manual re-optimization intervention is performed across large networks, then LSP paths can be optimized for maintenance, but significant delays and operational complexity are introduced
Solution Approach 1:
The patent implements self-service by enabling the network to automatically perform re-optimization operations without extensive manual intervention. The system autonomously monitors LSP performance, identifies optimization opportunities, and executes re-routing operations based on pre-configured policies and maintenance schedules, eliminating the need for operators to manually coordinate re-optimization across numerous LSPs while maintaining high reliability.
Solution Approach 2:
The patent applies parameter changes by dynamically modifying LSP attributes such as bandwidth allocations, priority levels, and routing metrics during re-optimization events. By changing these parameters in response to maintenance schedules and network conditions, the system achieves reliable LSP optimization without manual intervention, allowing rapid adaptation to maintenance requirements while minimizing operational delays.
3Loss of time
If proactive re-optimization is implemented, then maintenance downtime is reduced, but signaling overhead and system complexity increase
Solution Approach 1:
The patent applies partial action by implementing re-optimization selectively for only those LSPs that are scheduled for maintenance or have performance degradation, rather than forcing universal re-optimization of all LSPs. This selective approach reduces signaling overhead and system complexity by focusing computational and signaling resources only on the subset of LSPs that require optimization, while still achieving reduced maintenance downtime for critical paths.
Data Source
AI summary
A technique for mid-span re-optimization of traffic engineered label switched paths within a network that uses a label switching protocol (e.g., MPLS) enables a network operator to move traffic to quickly prepare for link or nodal maintenance. The technique establishes, at an intermediate router, a first label switch path (LSP) along a path between an ingress router and an egress router. The intermediate router forwards traffic via the first LSP and establishes a bypass tunnel to protect against link failure between the intermediate router and a next intermediate router on the first LSP. The intermediate router continues forwarding traffic on the first LSP, instead of the bypass tunnel, based on the receipt of a link failure simulation instruction at the intermediate router from a network administration node. The intermediate router discontinues forwarding the traffic via the first LSP based on the receipt of second signaling.