WSON Topology Abstraction for SDN Path Computation
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Solution Overview
Problem
In software defined networking (SDN) environments, maintaining a network topology for multiple domains, especially heterogeneous ones including packet and optical domains, is prohibitive for a Multi-Domain Service Coordinator (MDSC) due to the sheer amount of data required, making it impractical to calculate end-to-end paths efficiently.
Innovation Solution
An abstraction of the wavelength-switched optical network (WSON) topology is provided to the MDSC, determining maximal optical channel paths and bandwidth equivalent coding, using lambda planes to confine optical topologies and calculate maximal flows, while considering latency thresholds, and reporting available paths through a northbound interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a full network topology is maintained by the MDSC for all network domains, then complete path computation capability is achieved, but system complexity and data storage requirements become prohibitive
Solution Approach 1:
The patent segments the network topology management into two levels: domain-level SDN controllers maintain detailed topologies for their respective domains, while the MDSC maintains an abstracted inter-domain topology. This segmentation allows the MDSC to compute end-to-end paths across domains without storing complete domain-level topology details, thereby reducing complexity while preserving path computation capability.
Solution Approach 2:
The patent introduces domain-level SDN controllers as intermediaries between the MDSC and individual network domains. These intermediaries handle detailed topology management within their domains and provide abstracted topology information to the MDSC, enabling the MDSC to perform end-to-end path computation without directly managing complete network topology data.
2Measurement precision
If detailed optical topology information is provided to the MDSC, then accurate path computation is achieved, but data transmission and processing overhead increases
Solution Approach 1:
The patent extracts only the essential topology information needed for inter-domain path computation and presents it to the MDSC, while leaving detailed domain-level topology information at the domain controllers. This extraction approach maintains path computation accuracy for end-to-end routing while significantly reducing the volume of topology data that must be transmitted and processed by the MDSC.
3Adaptability or versatility
If complete network topology is maintained, then all path options are visible, but computation time and processing resources increase
Solution Approach 1:
The patent segments path computation into two stages: first, domain-level controllers compute paths within their domains using detailed local topology; second, the MDSC computes inter-domain paths using abstracted topology from multiple domains. This segmentation reduces computation time at each stage while maintaining visibility of all necessary path options for end-to-end routing.
Solution Approach 2:
The patent performs preliminary path computation at domain level before inter-domain path computation at the MDSC level. Domain controllers pre-compute and validate paths within their domains, then provide these pre-processed path options to the MDSC for end-to-end assembly. This preliminary action reduces the computational burden on the MDSC and accelerates overall path computation.
Data Source
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AI summary
A method including determining, for each reachable source-destination (S-D) node pair, a maximal number of optical channel (OCh) paths available for source-destination node pair connections and determining, if a preselected latency threshold is specified, for all available OCh paths a maximal number of paths satisfying the preselected latency threshold. The available OCh paths are reported to a Multi-Domain Service coordinator (MDSC).