Online routing, distance-adaptive modulation, and spectrum allocation for dynamic traffic in elastic optical networks

• Published in: Optical fiber technology Vol. 53; p. 102026
• Main Author: Khan, Akhtar Nawaz
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-12-2019
• Subjects: Blocking probability; Contiguity constraint; Continuity constraint; Elastic optical networks; Routing and spectrum allocation; Elastic optical networks; Routing and spectrum allocation; Blocking probability; Continuity constraint; Contiguity constraint
• ISSN: 1068-5200; 1095-9912
• DOI: 10.1016/j.yofte.2019.102026

•A routing algorithm is proposed for elastic optical networks with mixed line rates.•Routing decisions are initially made based on the modulation scheme with high data rates.•A route with maximum idle FS is preferred in case of multiple routes with same modulation.•If a tie occurs further, routing decision is made based on minimum hop count.•The proposed algorithm considers the first-last-mixed-fit spectrum allocation.•The proposed algorithm minimizes fragmentation and increases path contiguity.
In this work, an adaptive routing, modulation, and spectrum allocation (RMSA) scheme is proposed for dynamic traffic in elastic optical networks (EON) which allocates resources based on EON characteristics during the RMSA decision process. The proposed scheme selects a route from the set of available paths which efficiently utilizes available resources on all links during network operation stage. Initially, routes are determined from the set of available paths based on a feasible modulation scheme with higher data rates and requiring minimum contiguous frequency slots (FSs) as well as satisfying optical reach of the modulated signal. During the operation stage, routes between end pairs are determined from these preselected paths based on maximum idle FSs on a path. This increases resources utilization on the underutilized routes with maximum path contiguity and having minimum fragmentation. In case of tie among routes with similar numbers of maximum idle FSs, the proposed algorithm selects a path with minimum numbers of hops. Finally, the proposed routing algorithm is integrated with the proposed first-last-mixed fit spectrum allocation scheme which increases average path contiguity and reduces average path external fragmentation for connection requests with mixed line rates requiring contiguous FSs. Simulation results show that the proposed RMSA scheme efficiently reduces the amount of blocking probability, reduces average path external fragmentation, increases average resources utilization, and increases average path contiguity in different network scenarios compared to the existing minimum hop based routing and k-distance adaptive paths (KDAP) routing schemes.