2-Step Optimization for Wavelength Assignment in Optical Networks
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Solution Overview
Problem
Current methods for routing and wavelength assignment in multi-cable multi-fiber optical WDM networks fail to efficiently provision survivability through combined dedicated and shared protection mechanisms, leading to suboptimal wavelength utilization and increased connection switching times, especially with variable numbers of 1+1 dedicated and shared connections, and are not scalable for real-time applications.
Innovation Solution
A 2-step optimization procedure that modifies a layered graph to balance network communications, allocates wavelengths for shared routes, and uses a modified Bhandari's procedure to find link-disjoint routes, maximizing wavelength sharing and minimizing new wavelength links, while addressing routing and wavelength assignment sub-problems sequentially.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 1+1 dedicated protection is deployed to ensure survivability, then reliability is improved, but wavelength utilization deteriorates
Solution Approach 1:
The patent combines dedicated protection (1+1) and shared protection mechanisms into a hybrid approach. Backup wavelengths are shared among multiple working connections that are routed on fiber cable-disjoint routes, while maintaining dedicated protection for critical paths. This merging allows the system to achieve both high reliability and improved wavelength utilization by avoiding the exclusive allocation of dedicated backup wavelengths to single connections.
Solution Approach 2:
The patent implements a universal backup wavelength assignment mechanism where a single backup wavelength can serve multiple working connections simultaneously. The shared protection mechanism allows one backup wavelength to be allocated to multiple traffic demands, making the backup resource multi-functional rather than dedicated to a single connection, thereby improving overall wavelength utilization while maintaining survivability.
2Quantity of substance
If shared protection is used to improve wavelength utilization, then wavelength utilization is improved, but connection switching time deteriorates
Solution Approach 1:
The patent segments the protection mechanism into two distinct components: dedicated protection for critical paths requiring fast switching, and shared protection for less critical paths where wavelength sharing is beneficial. This segmentation allows the system to optimize for different performance requirements in different parts of the network, maintaining fast switching where needed while achieving improved utilization where time sensitivity is lower.
Solution Approach 2:
The patent applies different protection strategies to different network paths based on their specific requirements. Critical paths receive 1+1 dedicated protection with dedicated backup wavelengths for minimal switching time, while non-critical paths utilize shared protection where backup wavelengths are shared among multiple connections. This local differentiation of protection quality allows simultaneous optimization of both switching speed and wavelength utilization across the network.
3Reliability
If the number of protection routes is increased to improve survivability, then reliability is improved, but device complexity deteriorates
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and pre-allocating backup wavelengths and routes during normal network operation. The routing and wavelength assignment algorithm proactively identifies suitable backup paths and assigns wavelengths before failures occur, storing this information in advance. This preliminary preparation eliminates the need for complex real-time calculations during failure events, reducing operational complexity while maintaining high survivability.
Solution Approach 2:
The patent implements feedback mechanisms where the network continuously monitors wavelength utilization and failure conditions, using this information to dynamically adjust protection assignments. The algorithm learns from past failures and utilization patterns to optimize future routing and wavelength assignment decisions, reducing the complexity of manual configuration and automated provisioning while improving overall network survivability.
Data Source
AI summary
The inventive 2-step-optimization procedure that addresses the generalized routing and wavelength assignment problem with variable number of combined 1+1 dedicated and shared connections for the first time. The proposed procedure results a solution in time that is polynomial of the input size. Thus, the time complexity of the 2-step-optimization procedure is significantly less than that of existing methods.