Modified Dijkstra Algorithm for Bidirectional Routing in Non-Fully Meshed Optical Networks
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Solution Overview
Problem
Conventional shortest path routing algorithms, such as Dijkstra's Algorithm, fail to effectively find bidirectional paths in non-fully meshed networks, particularly in wavelength division multiplexing (WDM) agile networks with reconfigurable optical add/drop multiplexer (ROADM) sites, as they assume unidirectional connections and lack domain-specific information to achieve fast routing solutions.
Innovation Solution
A modified Dijkstra algorithm is implemented in a constrained manner to determine a shortest, bidirectional path by defining vertices as ingress and egress points, maintaining a set of visited degrees to prevent revisiting, and configuring network elements to receive and transmit signals across bidirectional links, ensuring that each degree is not revisited during path determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Dijkstra's Algorithm is used for routing, then the algorithm is simple to implement, but it cannot find accurate bidirectional paths in non-fully meshed networks
Solution Approach 1:
The patent segments the network graph by creating separate ingress and egress vertex representations for each degree, and maintains a visited degrees set to track progress. This segmentation allows the algorithm to properly handle non-fully meshed networks by distinguishing between different types of vertex connections and preventing invalid path revisits, thereby achieving accurate bidirectional path finding while managing complexity through structured graph representation.
2Ease of operation
If the algorithm assumes unidirectional connections, then the routing computation is simpler, but bidirectional paths cannot be correctly determined
Solution Approach 1:
The patent applies asymmetry by treating ingress and egress connections differently in the graph representation. Each degree has distinct ingress vertices and egress vertices, with directed edges indicating the direction of signal flow. This asymmetric representation allows the algorithm to correctly model bidirectional paths in non-fully meshed networks while maintaining computational efficiency through the constrained Dijkstra approach that respects connection directionality.
3Productivity
If domain-specific information is not used, then the algorithm has broader applicability, but routing speed is reduced
Solution Approach 1:
The patent incorporates local quality by integrating domain-specific knowledge about ROADM behavior directly into the graph representation and algorithm constraints. The visited degrees set and the distinction between ingress and egress vertices reflect local network characteristics of non-fully meshed ROADM sites. This localized incorporation of domain knowledge enables faster routing computation for optical networks while maintaining the algorithm's adaptability to other network types through the generalizable constrained shortest path approach.
Data Source
AI summary
Shortest path routing systems and methods are presented for networks with non-fully meshed vertices or nodes. The systems and methods may include a shortest path routing method in a network with non-fully meshed vertices, a network with non-fully meshed vertices, and a system for implementing the shortest path routing methods. The shortest path routing systems and methods include modifications to the Dijkstra algorithm to more accurately model a network, such as an optical or photonic network. In an exemplary embodiment, the Dijkstra algorithm is modified to represent degrees at a site with an ingress vertex (e.g., a demultiplexer) and an egress vertex (e.g., a multiplexer). In another exemplary embodiment, in addition to representing degrees as ingress and egress vertices, the Dijkstra algorithm is modified to maintain knowledge of previously visited degrees to prevent revisiting a same degree in determining a shortest path.