LSP Preemption Selection by Bandwidth and Priority Sorting
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Solution Overview
Problem
In communication networks, preemption of lower priority Label Switched Paths (LSPs) to accommodate higher priority LSPs often results in bandwidth overshoot and excessive LSP preemption, leading to reduced network efficiency and potential control plane storms due to unnecessary preemption.
Innovation Solution
A method and apparatus that select LSPs for preemption by sorting them based on bandwidth and priority, marking them for preemption until the cumulative bandwidth exceeds the required gap, and configuring the routing engine to preempt only the necessary LSPs, thereby minimizing bandwidth overshoot and the number of preempted LSPs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lower priority LSPs are preempted to accommodate higher priority LSPs, then bandwidth availability for high priority traffic is improved, but bandwidth overshoot and excessive LSP preemption occur reducing network efficiency
Solution Approach 1:
The patent changes the parameter of preemption selection from arbitrary or first-come-first-served to a structured approach based on sorting LSPs by bandwidth and priority. By modifying how preemption candidates are selected (changing the selection parameters), the system achieves reliable bandwidth allocation for high priority traffic while minimizing unnecessary preemptions that would reduce network efficiency
Solution Approach 2:
The patent implements a feedback mechanism where the system monitors bandwidth requirements and selectively preempts only those LSPs whose cumulative bandwidth exceeds the gap needed. This feedback-based selective preemption prevents bandwidth overshoot and excessive preemption, maintaining network efficiency while ensuring high priority traffic receives necessary bandwidth
2Reliability
If more LSPs are preempted to ensure sufficient bandwidth, then bandwidth gap coverage is improved, but the number of preempted LSPs increases causing control plane storms
Solution Approach 1:
The patent applies partial action by preemting only the minimum necessary LSPs required to cover the bandwidth gap, rather than preempting all possible lower priority LSPs. By sorting LSPs by bandwidth and selectively marking them for preemption until the cumulative bandwidth exceeds the gap, the system achieves sufficient bandwidth coverage while minimizing the number of preempted LSPs, thereby preventing control plane storms
3Ease of manufacture
If arbitrary LSPs are selected for preemption, then implementation simplicity is maintained, but bandwidth optimization and network performance deteriorate
Solution Approach 1:
The patent segments the preemption decision process into distinct steps: sorting LSPs by bandwidth and priority, calculating the bandwidth gap, sequentially marking LSPs for preemption based on their position in the sorted list, and stopping when the cumulative bandwidth exceeds the gap. This segmented approach maintains implementation simplicity while achieving optimal bandwidth utilization and network performance through structured decision-making
Data Source
AI summary
Example methods, apparatus and articles of manufacture to select label switched paths (LSPs) for preemption are disclosed. A disclosed example method includes sorting a first list of first label switched paths based on their respective bandwidths and priorities to form a sorted first list, each of the label switched paths having a lower priority than a requested label switched path, sequentially marking the first label switched paths for preemption based on their position in the sorted list until a bandwidth associated with the marked label switched paths exceeds a bandwidth gap, and configuring a routing engine to preempt the marked first label switched paths.