Dynamic Routing Hold Time Based on SPF Calculation Load
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Solution Overview
Problem
Existing routing protocols face challenges in configuring SPF hold time parameters to achieve quick convergence with minimal routing table calculations for all topology change scenarios, often resulting in either excessive calculations or delayed convergence.
Innovation Solution
A method and apparatus that determine a hold time period based on the running time required for shortest path first calculations between routing devices, using a running time database to store values for each path, thereby preventing further routing table calculations during this period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a routing device performs routing table calculation immediately on receiving a new LSA, then the convergence speed is improved, but the CPU becomes busy for extended periods and routing stability deteriorates
Solution Approach 1:
The patent implements dynamic hold time adjustment based on network conditions and topology change frequency. The hold time is not fixed but adapts according to the current state of the network, allowing the system to balance between fast convergence and stability by modifying the delay parameter in real-time based on observed topology change patterns and network load.
2Reliability
If a fixed hold time is used to limit routing table calculations, then routing stability is improved, but convergence speed decreases
Solution Approach 1:
The patent changes the hold time parameter dynamically based on network conditions rather than using a fixed value. The system monitors topology change frequency and network state to adjust the hold time parameter, allowing it to be short when convergence is needed and long when stability is required, thus resolving the contradiction between fixed hold time stability and convergence speed.
3Reliability
If exponential hold time is used to balance convergence and stability, then routing stability is improved, but difficulty in parameter configuration increases
Solution Approach 1:
The patent implements self-service through automatic hold time adjustment based on observed network conditions. The system monitors topology change patterns and automatically configures appropriate hold time values without requiring manual parameter tuning. This eliminates the complexity of configuring exponential hold time parameters while maintaining the balance between convergence and stability that such parameters aim to achieve.
Data Source
AI summary
One of the embodiments of the present invention relates to a method for operating a routing device in a network. The method comprises: receiving, during routing table calculation for a first topology change associated with a first routing device, a message indicative of a second topology change associated with a second routing device; determining a time duration of a hold time period based on a running time required for performing shortest path first calculations for a shortest path between the routing device and the second routing device, wherein the running time is retrieved from a running time database and the running time database is configured to store plural values each of which is indicative of a running time required for performing shortest path first calculations for a shortest path between the routing device and each of other routing devices in the network, wherein during the hold time period, the routing device does not perform any further routing table calculation. The present invention also relates to corresponding routing device.