DWDM Control Plane Path Computation via On-Demand Constraint Validation
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Solution Overview
Problem
In Dense Wave Division Multiplexing (DWDM) network services, existing control plane systems face inefficiencies in routing due to hidden Layer 0 network constraints not being flooded, leading to potential route invalidation, crank back failures, and suboptimal service setup, especially in Layer 0 networks where node-level parameters are not fully propagated.
Innovation Solution
A method where intermediate nodes in a control plane network validate and modify Layer 0 attributes/constraints in setup messages, aggregating rejection causes and additional information to enable informed retry decisions without flooding all constraints, allowing for dynamic path reconfiguration and improved resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all Layer 0 constraints are flooded into the network, then path computation accuracy is improved, but network scalability deteriorates
Solution Approach 1:
The patent extracts only the necessary Layer 0 constraints related to the specific path being computed, rather than flooding all constraints into the network. The path computation element retrieves constraint information on-demand from network elements along the computed path, reducing network overhead while maintaining computation accuracy.
Solution Approach 2:
The patent performs preliminary path computation using available information, then validates and refines the path by querying network elements along the path for specific constraint information. This two-stage approach allows accurate path computation without requiring all constraints to be pre-flooded into the network.
2Reliability
If crank back is used to re-route calls, then route validity is improved, but service setup time increases
Solution Approach 1:
The patent performs preliminary validation of Layer 0 constraints during the path computation stage by querying network elements before call setup. This prevents invalid routes from being selected in the first place, eliminating the need for time-consuming crank back operations later.
Solution Approach 2:
The patent implements a feedback mechanism where the path computation element queries network elements along the computed path to validate constraints before finalizing the route. This feedback loop ensures route validity is confirmed upfront, preventing subsequent crank back failures and reducing service setup time.
3Ease of operation
If centralized approach is used for path computation, then routing decisions are simplified, but adaptability to real-time network conditions deteriorates
Solution Approach 1:
The patent introduces a path computation element as an intermediary between the control plane and network elements. This mediator simplifies routing decisions by centralizing path computation logic while maintaining real-time adaptability by querying network elements for current constraint information on-demand, rather than relying on static centralized databases.
Solution Approach 2:
The patent makes the path computation system dynamic by allowing the path computation element to query network elements for real-time constraint information during path computation. This enables the system to adapt to current network conditions while maintaining the simplicity of centralized routing decision-making.
Data Source
AI summary
A method, in an intermediate node in a control plane network, includes receiving a setup message from an originating node, wherein the setup message is sent towards a terminating node on a computed path in the control plane network, and the setup message indicates associated Layer 0 attributes; validating the associated attributes/constraints based on locally available resources; and performing one of: forwarding the setup message on the path towards the terminating node when validation is successful; forwarding the setup message on the path towards the terminating node with updated information indicating a rejection cause and additional information when the validation is unsuccessful, but a modification of the Layer 0 attributes/constraints is possible; and forwarding a release message on the path back to the originating node with updated information indicating a rejection cause and additional information when the validation is unsuccessful and no modifications of the Layer 0 attributes/constraints are possible.