Spectrum Allocation Policy in Elastic Optical Networks

Abstract

Abstract-The considered problem covers routing and spectrum allocation problem (RSA problem) in Elastic Optical Networks while maintaining the spectrum continuity constraints, non-overlapping spectra constraints for adjacent connections on individual links of the network and spectrum contiguity constraints of the connection. In this article the modified version of the First Fit spectrum slot allocation policy for Fixed Alternate Routing in flexible optical networks has been proposed. The Fixed Alternate Routing with proposed spectrum allocation policy rejects fewer requests, provides less bandwidth blocking probability and less spectrum fragmentation than Fixed Alternate Routing with well-known First Fit and Exact Fit spectrum allocation policies. However, the cost of improving these parameters is a higher computational complexity of the proposed allocation policy.

Joint routing, link capacity dimensioning, and switch port optimization for dynamic traffic in optical networks

“…However, it is a greedy algorithm in which some links are shared more frequently than others and is not suited for network design process and resource allocation [ 23 ]. Similarly, alternate routing considers a set of two or three shortest paths between end nodes using the k-shortest path routing scheme; these paths are also found using Dijkstra ' s algorithm [ 21,24,25 ]. In a dynamic network scenario, when resources are not available on the first shortest path, traffic is routed on the second shortest path using an alternate routing scheme that minimizes the congestion in the network.…”

Link Congestion Aware Proactive Routing for Dynamic Traffic in Elastic Optical Networks

“…In dynamic RSA problems, ligthpath requests with finite holding time and variable bandwidth demands arrives randomly and hold resources in the network till departure. The goal of the dynamic RSA problem is to reduce the probability of bandwidth blocking [24], [25] which can be divided into routing subproblem and spectrum allocation subproblem [26], [27]. A global optimizaiton method has been proposed in [28] called cross stratum optimization (CSO) which dynamically allocates resources according to the modulation format and bandwidth requirements in EON.…”

“…An online unsupervised fuzzy clustering algorithm is used for resource allocation in [34] which takes into account physical impairements in EON. Similarly, first-fit, last-fit, random-fit, most-used, and least-used heuristics have been used for spectrum allocation in EON [19], [22], [26], [30]. Fragmentation is a major issue in EON which in large is related to the spectrum allocation techniques.…”