Protection lightpath-based hitless spectrum defragmentation for distance adaptive elastic optical networks.

Area of Science:

• Optical Networking
• Telecommunications Engineering
• Network Optimization

Background:

• Elastic Optical Networks (EONs) require efficient spectrum utilization.
• Existing spectrum defragmentation often impacts active network services.
• Protection lightpaths offer a potential avenue for hitless defragmentation.

Purpose of the Study:

• To propose and evaluate a hitless spectrum defragmentation scheme for EONs using protection lightpaths.
• To achieve spectrum defragmentation without affecting working lightpaths and upper-layer services.
• To reduce the bandwidth blocking probability (BBP) in distance-adaptive EONs.

Main Methods:

• Implemented protection lightpath-based hitless spectrum defragmentation.
• Utilized Shared Backup Path Protection (SBPP) for evaluation.
• Proposed two defragmentation triggering mechanisms: defragmentation upon blocking (BTD) and batch defragmentation (BD).
• Developed two defragmentation algorithms: sequentially releasing and re-establishing (SR-D) and jointly releasing and re-establishing (JR-D).

Main Results:

• The proposed scheme effectively reduces BBP compared to no defragmentation.
• The reduction in BBP comes with a trade-off in the average number of reconfigurations (ANR).
• Both BTD and BD triggering mechanisms, coupled with SR-D and JR-D algorithms, demonstrate effectiveness.

Conclusions:

• Protection lightpath-based hitless spectrum defragmentation is a viable strategy for EONs.
• The proposed methods improve spectrum utilization and reduce BBP.
• Careful consideration of the BBP and ANR trade-off is necessary for practical implementation.