TRILL SPF Computation Selective Triggering
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Solution Overview
Problem
In TRILL networks, the frequent re-computation of Shortest Path First (SPF) values due to link-state protocol changes can overwhelm network resources, especially as the network grows and traffic increases, leading to inefficient packet traffic management.
Innovation Solution
Implementing a method where SPF computation in a distributed network is performed only when a predetermined event occurs that impacts the link state protocol, using a processor to identify changes and determine if they require SPF recalculation, thereby reducing unnecessary computations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SPF computation is performed for every link-state protocol change in a TRILL network, then routing accuracy is maintained, but network resources are overwhelmed
Solution Approach 1:
The patent applies partial action by selectively triggering SPF computation only when specific link-state changes actually impact the shortest path tree, rather than computing SPF for every link-state protocol change. This filters out unnecessary computations while maintaining routing accuracy for changes that matter.
Solution Approach 2:
The patent changes the parameter of SPF computation frequency from constant (every LSP change) to conditional (only when impacting SPF values). This parameter change optimizes network resource usage while preserving routing reliability by adapting computation frequency to actual network conditions.
2Productivity
If SPF computation is performed frequently to maintain accurate routing tables, then routing efficiency is improved, but computation time increases
Solution Approach 1:
The patent performs SPF computation partially - only when link-state changes impact the shortest path tree. This reduces the frequency of full SPF computations while maintaining routing efficiency for affected paths, thereby reducing overall computation time.
Solution Approach 2:
The system uses the link-state protocol changes themselves to trigger selective SPF computations. The link-state changes provide self-information about when SPF computation is necessary, eliminating the need for continuous or periodic computations.
3Adaptability or versatility
If the network grows larger with more trees and traffic, then network coverage and capacity increase, but SPF computation overhead increases
Solution Approach 1:
The patent applies partial action by computing SPF only for affected trees and paths when link-state changes occur, rather than recomputing SPF for all trees in the network. This scales computation effort with actual network changes rather than total network size.
Solution Approach 2:
The patent segments the SPF computation process by identifying and processing only the specific trees and paths affected by link-state changes, rather than treating the entire network as a single computation unit. This reduces complexity by dividing the problem into smaller, manageable segments.
Data Source
AI summary
A shortest path first (SPF) computation in a distributed network may be performed efficiently by performing the SPF computation in stages. Rather than perform a new SPF computation every time a change occurs affecting a link state within the distributed network, a routing protocol may identify the change and determine if the impact to the link state necessarily needs the new SPF computation. For example, a predetermined list of events may identify changes that may not necessarily impact the SPF value(s) currently associated with the distributed network. Embodiments disclosed may avoid computation of the new SPF for changes to the link state thus managing network system resources more efficiently.