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Spectrum Fragmentation Management Approaches in 1+1 Protected Elastic Optical Networks
Published in Bijoy Chand Chatterjee, Eiji Oki, Elastic Optical Networks: Fundamentals, Design, Control, and Management, 2020
Bijoy Chand Chatterjee, Eiji Oki
Shared protection techniques reduce the spectrum resource used for protection. In [141], the authors considered span restoration in elastic optical networks. They develop integer linear programming (ILP) models to minimize both required spare capacity and maximum used spectrum slots index under different spectrum conversion capabilities. They considered (i) no spectrum conversion, (ii) partial spectrum conversion, and (iii) full spectrum conversion. The authors of [222] considered the p-cycle protection technique, which provides ring-type protection and the speed of restoration of meshes. Similar to [141], they aimed to minimize required spare capacity and the maximum used spectrum slots index and formulated an ILP problem. Both works in [141] and [222] also apply the bandwidth squeezed restoration (BSR) technique [144]. In [223], the authors presented algorithms that provide path protection using p-cycle paths. They claim 100% protection against single and double link failures.
Double-Link Failure Protection Using a Single p-Cycle
Published in IETE Journal of Research, 2022
Pallavi Athe, Yatindra Nath Singh
Pre-configured cycle (p-Cycle) protection has mesh-like efficiency and ring-like speed [12–17]. p-Cycles are ring structures formed using spare capacity available in a mesh network. The links part of the cycle are called on-cycle links. A straddling link is a chord with only their end nodes on the cycle. A p-cycle can protect the working capacity of the on-cycle and the straddling links. An on-cycle link has one, while a straddling link has two paths to reroute its traffic on a p-cycle. Therefore, a single copy of a p-cycle can provide unit capacity protection to an on-cycle link and two-unit capacity protection to the straddling links on it. The ring-like structure provides switching speed to p-cycles, and the ability to protect on-cycle and straddling links makes p-cycles spare capacity efficient.