Directionless ROADM Routing Module for Network Failure Rerouting
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Solution Overview
Problem
Existing reconfigurable optical add-drop multiplexer (ROADM) based optical nodes face inflexibility in mesh networks due to dedicated add and drop ports, which limits network flexibility during failures such as fiber and node failures, as they cannot efficiently reroute wavelengths to different transponders.
Innovation Solution
The implementation of at least two reconfigurable optical add-drop multiplexers (ROADMs) and a routing module within an optical node, allowing for the transmission of wavelength division-multiplexed signals onto multiple internode paths and enabling channels of the same wavelength to be directed to different paths, with tunable filters and passive optical couplers centralized within the add-drop routing module rather than the ROADM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If dedicated add/drop ports are assigned to specific transponders, then the ROADM structure is simple and easy to implement, but network flexibility and failure recovery capability deteriorate
Solution Approach 1:
The patent implements directionless add/drop ports that can serve multiple transponders universally. Each add/drop port is no longer dedicated to a single transponder but can dynamically connect to any transponder in the network, enabling a single port to perform multiple functions across different network configurations and failure scenarios.
Solution Approach 2:
The patent introduces dynamic reconfiguration capability where the connections between add/drop ports and transponders can be changed in real-time. The system can dynamically switch connections to reroute signals around failures or optimize network traffic, transforming a static dedicated connection model into a dynamic flexible connection model.
2Ease of manufacture
If dedicated add/drop ports are assigned to specific transponders, then port configuration is simple, but failure recovery capability deteriorates
Solution Approach 1:
The add/drop ports are designed with universal functionality to serve any transponder, enabling automatic failover to alternative transponders when failures occur. This universal design allows the same port to be reassigned to different transponders dynamically, providing built-in redundancy and failure recovery capability.
Solution Approach 2:
The system enables dynamic reconfiguration of port-to-transponder mappings in response to failures. When a failure is detected, the system can automatically switch connections to restore service through alternative paths, providing rapid failure recovery without manual reconfiguration.
3Reliability
If multiple ROADMs are used to transmit WDM signals onto multiple paths, then network resilience improves, but device complexity increases
Solution Approach 1:
The patent merges the functionality of multiple ROADMs into a unified optical node structure with centralized control. Instead of having completely independent ROADMs, the system integrates multiple ROADM functions into a coordinated unit that shares resources and control logic, reducing overall system complexity while maintaining multi-path capability.
Solution Approach 2:
The ROADMs in the system are designed with universal add/drop port capabilities that can serve multiple transponders and network paths. This multi-functionality allows fewer ROADMs to perform the work of what would traditionally require more dedicated devices, reducing the total number of ROADMs needed while maintaining network resilience.
4Productivity
If channels of the same wavelength are directed to different paths, then wavelength blocking is reduced, but routing control complexity increases
Solution Approach 1:
The system implements feedback mechanisms that monitor network conditions and automatically adjust routing decisions. When wavelength blocking is detected or network conditions change, the feedback system triggers reconfiguration to direct channels to alternative paths, optimizing wavelength utilization without requiring complex manual control.
Solution Approach 2:
The routing system performs self-optimization by automatically detecting blocking conditions and reconfiguring paths without external intervention. The system monitors its own state and takes corrective action to prevent wavelength blocking, reducing the need for complex external routing control.
Data Source
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AI summary
In today's reconf?gurable optical add/drop multiplexer (ROADM) based optical node, ROADMs multiplex (and demultiplex) colored optical signals to form wavelength-division multiplexed (WDM) signals. Transponders connected to the ROADMs' add/drop ports convert noncolored optical signals to colored optical signals (and vice versa). Dedicating transponders to given ports degrades the node's ability to route around network failures. Example embodiments of the invention include an optical node and corresponding method for routing optical signals within an optical node that compensate for this inflexibility. The optical node may include two ROADMs to transmit respective WDM signals onto at least two internode network paths and a routing module that can direct channels of the same wavelength along different internode network paths. Advantageously, a transponder may transmit (receive) different signals at the same wavelength to (from) different network node interfaces within the optical node, thereby improving the optical node's ability to route around network failures.