ASA: Adaptive Spectrum Allocation Schemes to Reduce Spectrum Fragmentation in Elastic Optical Networks

To fulfils the current torrent of high speed and flexible bandwidth internet traffic demand, Elastic Optical Network (EON) played a vital role in data transmission and communication systems. The present work addresses spectrum fragmentation (SF) problem occurs in EONs due to the varied bandwidth requirement and unequal allocation of frequency slots (FSs) to accommodate the connection requests. In this paper, we propose three Adaptive Spectrum Allocation (ASA) schemes namely RSA-ASA1, RSA-ASA2, and RSA-ASA3, each adopting a different spectrum allotment criterion. Each ASA scheme has been evaluated and tested on the standard ARPANET network topology and their performance is compared with the conventional first fit spectrum allocation (SA) policy, termed as RSA-FF, on three different metrics: network spectrum fragmentation (NSF), the number of connections established, and spectrum utilization ratio (SUR). The simulation outcome of the proposed ASA scheme shows improved results as compared to RSA-FF scheme. The NSF value of the proposed RSA-ASA1, RSA-ASA2, RSA-ASA3 schemes reduces 5.13%, 3.34%, and 6%, respectively as compared to the RSA-FF scheme. Similarly, each proposed scheme increases the number of connections established. Among all the schemes RSA-ASA3 scheme outperforms on each evaluating metrics.