Requested bandwidth adaptive network state based adaptive routing and spectrum allocation algorithms in Elastic Optical Network

The advent of 5G networks has revolutionized communication technology and offers heterogeneous data rates and low latency. Elastic Optical Networks (EONs) have emerged as a critical enabler for the next generation transport network in 5G, offering dynamic and flexible spectrum allocation to support the high-capacity and heterogeneous traffic requirements. EONs leverage advanced technology such as flexible grid architecture to optimize spectrum utilization. The resource management in these networks is assumed to governed by the software defined networking (SDN) controller which executes the Routing, and Spectrum Allocation (RSA) algorithms. The complexity in the RSA arises due to two critical constraints: spectrum contiguity and spectrum continuity. These constraints along with spectrum non-overlapping constraint need to be followed for accommodating dynamic traffic. The spectrum contiguity problem is solved by the proposed Requested Bandwidth aware Adaptive Routing and Spectrum Allocation (RB-ARSA) algorithm, in which only those links of the network topology participate in the path computation which satisfy the spectrum contiguity constraints for the requested bandwidth. While the spectrum continuity constraint can be resolved by using spectrum constraint-sharing path based RSA algorithm simultaneously along with the RB-ARSA algorithm, known as Requested Bandwidth-aware Spectrum Constraints Sharing Path based Adaptive Routing and Spectrum Allocation (RB-SCSP-ARSA) Algorithm. The algorithms presented in this paper leverage network state information that is aware of the requested bandwidth to enhance overall network performance. This paper emphasizes the significance of computationally sophisticated heuristic algorithms in minimizing bandwidth blocking probability (BBP) while facilitating effective resource allocation. To measure the effectiveness of the proposed algorithms following performance metrics are used: BBP, request blocking probability (RBP), accepted load, fractional spectrum utilization, link fragmentation metric, and entropy based fragmentation metric. The main objective of the proposed algorithms are to provide a network state that adjusts according to the requested bandwidth; consequently, the primary performance metric analyzed in this study is BBP, while the other metrics are considered secondary. The K=1 RSA, K=3 RSA, and RSA-WP function as the benchmark algorithms for this analysis. It is important to note that these benchmark algorithms do not consider the spectrum constraints of the links prior to resource provisioning, whereas our proposed algorithms are specifically designed to take these constraints into account. These benchmarks are utilized to assess the performance differences between spectrum constraint-aware versus spectrum constraint-unaware algorithms. K-RSA operate as a network state-unaware algorithms, in contrast to our proposed algorithms, which are network state-aware. Consequently, the K-RSA benchmark algorithms are used to evaluate the performance of network state-aware versus network state-unaware algorithms. The simulation results indicate that the proposed algorithms achieve a significant reduction in the key performance metric BBP, with reductions of 30.1% for RB-ARSA and 44.5% for RB-SCSP-ARSA when compared to the benchmark algorithms.