Optical Network Slot Allocation for GMPLS Scalability
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Solution Overview
Problem
Traditional wavelength assignment strategies in optical networks, such as 'first-fit', do not guarantee efficient network resource utilization, especially in flexible grid scenarios with high frequency slots, leading to scalability issues with the GMPLS protocol.
Innovation Solution
A method and apparatus that allocate consecutive slots in optical networks by selecting the first available slot at a multiple of n and reserving the next n-1 slots, depending on the transmission type, bit-rate, and modulation format, grouping slots to reduce scalability issues and improve GMPLS protocol efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional first-fit wavelength assignment strategy is used, then slot allocation is simple, but network resource utilization efficiency deteriorates
Solution Approach 1:
The patent segments the frequency spectrum into discrete slots of uniform width (e.g., 12.5 GHz or 6.25 GHz slots). Each slot can be independently allocated to different lightpaths, enabling fine-grained resource management. This segmentation allows the system to efficiently pack multiple transmissions into the available spectrum while maintaining simple allocation rules based on slot indices.
2Productivity
If flexible grid with high number of frequency slots is introduced, then spectral efficiency is improved, but scalability of GMPLS protocol deteriorates
Solution Approach 1:
The patent changes the fundamental parameter of frequency slot identification from using absolute frequency values (which would require large Label Set objects in flexible grids) to using relative slot indices within a standardized grid structure. This parameter transformation allows the same GMPLS protocol framework to handle both traditional wavelength-scale networks (40-80 wavelengths) and flexible grid networks (320-640 slots) without protocol extension, as the Label Set object size remains manageable.
3Reliability
If contiguous slots are allocated for each transmission type, then transmission requirements are met, but slot availability information management becomes complex
Solution Approach 1:
The patent performs preliminary grouping of contiguous slots into logical units before allocation. By pre-organizing the slot structure and maintaining availability information in a standardized format, the system simplifies the lightpath setup process. When a lightpath request arrives, the system can quickly determine slot availability without complex real-time calculations, as the slot grouping and availability status are already prepared.
Data Source
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AI summary
Slots (311) for transmission of data of a particular transmission type over an optical network are allocated by selecting a first available slot (313_2) at an ordinal position corresponding to a multiple of n and allocating the selected first available slot and the next n-1 consecutive slots (313_4, 313_5) from the selected first available slot (313_3), if all n-1 consecutive slots (313_4, 313_5) are available, for transmission of data of the particular transmission type. The data is transmitted over an optical network comprising a plurality of nodes (305, 327) interconnected by optical sections (301, 309, 329, 331) the nodes (305, 327) supporting a plurality of transmission types, wherein transmission of data of the particular transmission type requires a predetermined number n of consecutive slots. Alternatively the slots may be divided in groups (333, 335, 337) and slots are allocated to a group in which all slots are available.