Port Wavelength Restriction Encoding in Optical Networks
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Solution Overview
Problem
In wavelength switched optical networks (WSONs), determining the routing and wavelength assignment (RWA) for signals is challenging due to the need to consider port wavelength restrictions at network elements (NEs), which requires accurate encoding and processing of port wavelength restriction information to establish suitable lightpaths without interference.
Innovation Solution
The system encodes port wavelength restriction information in Type-Length-Value (TLV) messages and uses a Path Computation Element (PCE) to process this information, enabling the calculation and establishment of lightpaths that adhere to the wavelength constraints of NEs, employing different TLV types for various restriction types such as simple-wavelength, channel-count, and waveband restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If port wavelength restriction information is encoded and processed at the PCE to determine routing and wavelength assignment, then routing accuracy and wavelength constraint compliance are improved, but network complexity and processing overhead increase
Solution Approach 1:
The patent introduces a Path Computation Element (PCE) as an intermediary that centralizes the processing of port wavelength restriction information. The PCE receives encoded restriction data from network elements, processes this information to determine compliant lightpaths, and returns routing decisions. This mediator approach improves routing accuracy by consolidating complex constraint handling in a dedicated component while maintaining standardized interfaces that limit overall system complexity.
2Loss of information
If multiple TLV types are used to encode different restriction types (simple-wavelength, channel-count, waveband), then encoding precision and information completeness are improved, but message complexity and processing difficulty increase
Solution Approach 1:
The patent segments port wavelength restriction information into distinct Type-Length-Value (TLV) structures, with different TLV types for different restriction categories (simple-wavelength, channel-count, waveband). Each TLV type encodes specific restriction parameters in a standardized format. This segmentation allows complete representation of diverse constraints while maintaining manageable message complexity through consistent encoding rules and type identification mechanisms.
Solution Approach 2:
The patent uses parameter changes within the TLV structure to represent different restriction types. By varying the TLV type identifier and associated parameters (such as wavelength values, channel counts, or waveband definitions), the system can encode multiple restriction categories using a unified message framework. This approach maintains information completeness while avoiding the need for entirely separate message formats for each restriction type.
3Reliability
If port wavelength restriction information is forwarded from PCC to PCE for path computation, then routing reliability and constraint compliance are improved, but communication overhead and processing time increase
Solution Approach 1:
The patent implements preliminary action by having network elements (PCCs) pre-encode their port wavelength restriction information in standardized TLV formats before forwarding to the PCE. This preprocessing ensures that the PCE receives ready-to-process, structurally validated constraint data, improving routing reliability. The encoding is performed in advance based on local port capabilities, eliminating the need for real-time constraint discovery during path computation and reducing overall processing time.
Data Source
AI summary
An apparatus comprising a path computation element (PCE) coupled to a path computation client (PCC) and configured to perform a path computation using port wavelength restriction information for a network element (NE), wherein the port wavelength restriction information is encoded and received in a port wavelength restriction Type-Length-Value (TLV) that comprises a matrix identifier (ID), a restriction type, and the port wavelength restriction information. Also disclosed is a network component comprising at least one processor coupled to a memory and configured to receive a port wavelength restriction information TLV that corresponds to a NE, and obtain a restriction type and port wavelength restriction information based on the restriction type from the port wavelength restriction TLV, and use the port wavelength restriction information to calculate a path for the NE.