Bandwidth Advertisement Update Method for Optical Transport Networks
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Solution Overview
Problem
Conventional bandwidth advertisement systems in optical networks face scalability issues due to excessive messaging during network restoration or reconfiguration, especially in large domains with dense wave division multiplexing links, and fail to accurately represent available capacity for aggregated links with multiple ODUk tributaries.
Innovation Solution
Implementing a bandwidth advertisement update method that sets threshold values for each bandwidth unit, allowing updates only when available bandwidth falls below these thresholds, thereby reducing unnecessary messaging and supporting aggregated links while maintaining compliance with GMPLS and ASON control planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional bandwidth advertisement systems advertise actual capacity for each ODUk rate, then bandwidth information accuracy is improved, but messaging cost and processing complexity increase exponentially during network restoration or reconfiguration
Solution Approach 1:
The patent changes the parameter of bandwidth advertisement from advertising actual capacity to advertising supported capacity (maximum capacity). This parameter change transforms the advertisement from a dynamic value that changes with each bandwidth allocation to a static value that remains constant until the interface becomes incapable of supporting a given ODUk rate, thereby reducing processing complexity during network restoration or reconfiguration
Solution Approach 2:
The patent extracts the distinction between supported capacity and actual capacity. By advertising only supported capacity (the maximum capacity the interface can support) rather than actual capacity (the remaining available bandwidth), the system separates the capability advertisement from the state advertisement, reducing messaging overhead while maintaining necessary information for route selection
2Loss of time
If bandwidth advertisements are sent whenever available bandwidth changes, then bandwidth information freshness is improved, but network messaging overhead increases
Solution Approach 1:
The patent implements periodic action by establishing trigger conditions for bandwidth advertisements. Instead of continuous advertisement upon every bandwidth change, advertisements are sent periodically when specific conditions are met (when the interface becomes incapable of supporting a given ODUk rate), reducing messaging overhead while maintaining information freshness when necessary
Solution Approach 2:
The patent changes the trigger parameter for bandwidth advertisement from any bandwidth change to a threshold-based condition (when supported capacity changes). This parameter change reduces the frequency of advertisements by only triggering when the interface's capability changes, not when temporary bandwidth allocations change
3Productivity
If only supported ODUk rates are advertised (maximum capacity), then messaging efficiency is improved, but accuracy of available capacity information for aggregated LSPs deteriorates
Solution Approach 1:
The patent applies segmentation by treating aggregated LSPs as separate logical entities with their own bandwidth calculations. Each aggregated LSP's available capacity is calculated independently based on the supported capacity advertisement and the LSP's specific bandwidth requirements, allowing accurate capacity information for aggregated LSPs while maintaining messaging efficiency through supported capacity advertisements
4Loss of information
If ISCD messaging is used to advertise bandwidth for each ODUk container size, then comprehensive bandwidth information is provided, but processing cost during network restoration or reconfiguration increases
Solution Approach 1:
The patent changes the parameter of ISCD messaging from advertising actual available bandwidth to advertising supported capacity. This parameter change reduces processing cost during network restoration or reconfiguration because the advertisement content remains static until the interface capability changes, eliminating the need to recalculate and re-advertise bandwidth information with each bandwidth allocation change
Solution Approach 2:
The patent implements preliminary action by pre-calculating and advertising the supported capacity (maximum capacity) for each ODUk rate. This preliminary calculation is performed once when the interface is configured, and the result is advertised and reused until the interface capability changes, avoiding repeated processing during network operations
Data Source
AI summary
A bandwidth advertisement update method in an optical network, an optical network, and a controller provide a configurable mechanism for bandwidth advertisement updates in a control plane providing flexibility and reducing bandwidth advertisements in the control plane while concurrently supporting aggregated connections. The bandwidth advertisement update method includes defining a plurality of bandwidth update threshold values for a plurality of bandwidth units supported on a link in the optical network, responsive to a change in available bandwidth on the link, sending a bandwidth advertisement if the available bandwidth for any of the plurality of bandwidth units is less than the associated bandwidth update threshold value, and responsive to a change in available bandwidth on the link, withholding the bandwidth advertisement if the available bandwidth for all of the plurality of bandwidth units is greater than or equal to the associated bandwidth update threshold value.