Joint Optimization for Wavelength Assignment in Optical Networks
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Solution Overview
Problem
Current optical WDM networks face challenges in efficiently provisioning survivability through combined dedicated and shared protection mechanisms, leading to suboptimal wavelength utilization and increased channel switching time, especially in multi-cable multi-fiber networks, where existing solutions are either inefficient or not applicable for variable numbers of 1+1 dedicated and shared connections.
Innovation Solution
A joint optimization procedure is introduced that constructs a layered graph to find fiber cable link-disjoint routes, applies routing and wavelength assignment based on maximum sharing factors, and modifies Bhandari's procedure to maximize wavelength sharing, enabling efficient routing and wavelength assignment for variable numbers of dedicated and shared connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 1+1 dedicated protection routes are allocated to ensure survivability, then the survivability of traffic demand increases, but the wavelength utilization decreases
Solution Approach 1:
The patent combines dedicated protection and shared protection mechanisms into a unified protection scheme. Dedicated protection ensures immediate failover for critical connections, while shared protection allows backup wavelengths to be reused across multiple connections, thereby maintaining high survivability while improving wavelength utilization efficiency
Solution Approach 2:
The patent enables backup wavelengths to serve multiple functions: they can be used for dedicated protection when immediate failover is required, and simultaneously serve as shared backup resources for multiple other connections. This multi-functionality resolves the contradiction by making protection resources more versatile
2Loss of energy
If shared protection mechanism is used to improve wavelength utilization, then the wavelength resource utilization improves, but the connection switching time increases
Solution Approach 1:
The patent applies different protection qualities to different connections based on their requirements. Time-critical connections receive dedicated protection with immediate failover capability, while non-time-critical connections use shared protection. This local differentiation allows the system to optimize wavelength utilization without compromising the switching time requirements of critical applications
3Adaptability or versatility
If variable numbers of dedicated and shared connections are provisioned, then the adaptability to different traffic demands increases, but the complexity of routing and wavelength assignment increases
Solution Approach 1:
The patent segments the protection provisioning process into distinct phases: first determining the number of dedicated connections based on time-critical requirements, then allocating shared connections for remaining bandwidth needs. This segmentation transforms the complex joint optimization problem into a structured two-stage process, reducing computational complexity while maintaining flexibility
Data Source
AI summary
A joint-optimization method addresses the generalized routing and wavelength assignment problem with variable number of combined 1+1 dedicated and shared connections. The inventive method enables a solution in time that is polynomial of the input size. Thus, the time complexity of the joint-optimization method is significantly less than that of existing methods.