Routing Information Computation with Adaptive SPF Delay
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Solution Overview
Problem
Existing data communications networks face processing burdens and potential looping issues due to frequent SPF calculations triggered by successive network changes, which can be delayed by exponential back-off algorithms, leading to inadequate response times and network instability.
Innovation Solution
A method that differentiates between 'good news' and 'bad news' network changes to adjust SPF computation delays, allowing quicker computations for critical changes and longer delays for non-critical ones, using a flow diagram to identify change types and apply appropriate delay intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If exponential back-off algorithm is used to delay SPF calculations, then processing burden is reduced, but network responsiveness deteriorates
Solution Approach 1:
The patent applies different delay strategies to different types of network changes: 'good news' changes (link additions, cost reductions) use exponential back-off delays, while 'bad news' changes (link failures, cost increases) trigger immediate SPF calculations. This local differentiation resolves the contradiction by applying delay selectively rather than uniformly, reducing processing burden for non-critical changes while maintaining responsiveness for critical failures.
2Reliability
If SPF calculations are performed frequently to maintain network stability, then network stability improves, but processing burden increases
Solution Approach 1:
The patent changes the parameter of calculation delay based on the type of network change detected. By modifying the delay parameter dynamically - using short delays for bad news and long delays for good news - the system maintains network stability when necessary while reducing processing burden during non-critical updates.
Solution Approach 2:
The patent segments network changes into two categories: 'good news' (non-critical) and 'bad news' (critical). This segmentation allows the system to apply different processing strategies to different types of changes, maintaining stability for critical events while reducing burden for routine updates.
3Ease of operation
If uniform delay interval is applied to all network changes, then implementation simplicity is maintained, but network responsiveness to critical changes deteriorates
Solution Approach 1:
Instead of uniform delay application, the patent implements local quality by detecting the type of network change and applying appropriate delay strategies: immediate calculation for critical 'bad news' changes and delayed calculation for non-critical 'good news' changes. This resolves the contradiction by making the system simple to implement while being responsive to critical events.
Data Source
AI summary
A method is disclosed for computing routing information for a data communications network comprising a plurality of nodes. The method comprises the step performed at a computing node of receiving from a remote node in the network a routing information update representing a change of state of the network. The method further comprises processing the update to identify a change of state type and setting, dependent on the change of state type, a delay interval after which routing information is to be computed from the update.