Dynamic Routing Updates in Stateful PCE Environments
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Solution Overview
Problem
Stateful Path Computation Elements (PCEs) face challenges such as high signaling churn, state maintenance issues, scaling limitations, and increased instability due to burst signaling requests and network failures, particularly in scenarios where accurate bandwidth booking is critical.
Innovation Solution
A dynamic scheme is implemented to monitor tunnel set-up failure rates, adjusting routing update intervals and bandwidth booking thresholds to minimize call failures and enhance scalability, by extending PCEP messages to include failure rate information and dynamically adjusting threshold sets based on observed failure rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stateful PCE monitors and responds to each tunnel set-up failure with routing updates, then tunnel set-up success rate improves, but signaling churn increases
Solution Approach 1:
The patent implements dynamic adjustment of routing update intervals based on observed tunnel set-up failure rates. When failure rates exceed a threshold, the system shortens the routing update interval to improve accuracy; when failure rates are low, it lengthens the interval to reduce signaling churn. This dynamic adaptation resolves the contradiction by making the system responsive to actual network conditions rather than using fixed update frequencies.
Solution Approach 2:
The system changes the parameter of routing update interval dynamically based on tunnel set-up failure rate observations. By adjusting this temporal parameter in response to performance metrics, the system optimizes the balance between reliability (accurate routing information) and productivity (minimizing signaling overhead).
2Measurement precision
If routing update interval is shortened to improve routing accuracy, then tunnel set-up success rate improves, but signaling requests increase
Solution Approach 1:
The routing update interval is made dynamic rather than static. The system continuously monitors tunnel set-up failure rates and adjusts the update interval accordingly, shortening it only when necessary to improve routing accuracy and maintaining longer intervals during stable conditions to reduce signaling requests.
Solution Approach 2:
The system implements feedback control by monitoring tunnel set-up failure rates and using this information to adjust routing update intervals. This closed-loop approach ensures that routing information accuracy is improved only when the feedback indicates actual problems, rather than continuously updating regardless of network conditions.
3Measurement precision
If stateful PCE maintains detailed tunnel states for accurate bandwidth booking, then bandwidth booking accuracy improves, but device complexity increases
Solution Approach 1:
The patent extracts and monitors only the critical state information needed for bandwidth booking accuracy (tunnel set-up failure rates and routing update patterns) rather than maintaining complete detailed states of all tunnels. This selective state extraction maintains bandwidth booking accuracy while reducing the overall complexity of state management in the PCE.
Data Source
AI summary
In one embodiment, a device (e.g., a path computation element, PCE) monitors a tunnel set-up failure rate within a computer network, and determines whether to adjust an accuracy of routing information based on the tunnel set-up failure rate. For instance, the tunnel set-up failure rate being above a first threshold indicates a need for greater accuracy. In response to the tunnel set-up failure rate being above the first threshold, the device may then instruct one or more routers to shorten their routing update interval in the computer network.