Dispersion aware first random fit spectrum allocation approach in elastic optical network (EON)

Abstract Elastic Optical Network (EON) is gaining a lot of attention these days because of its capability to dynamically utilize the network resources. It is possible to alter data rates in accordance with the required application by adjusting a number of spectrum slots which enhances spectral efficiency. However, it is difficult for new requests to access the usage of spectrum resources during the entire process especially when the spectrum is split into a number of small segments. Another key challenge in EON is to achieve effective routing and spectrum allocation. This entails looking for a specified route and identifying contiguous aligned spectrum slots for allocation to various requests. In this way, EON aims maximizing the connection while using the least amount of available spectrum resources. With this in mind, this research developed a first random fit (FRF) spectrum allocation technique that takes into account dispersion, which is a major physical flaw in optical networks. This scheme includes the effect of dispersion for the spectrum allocation approach. Using a FRF approach, this scheme tends to allocate a greater number of connection requests and spectrum is utilized in more efficient way. Starting with the lowest indexed slot, this scheme uses the First Fit algorithm and the less stable modulation technique like BPSK to search for and assign the spectrum slot. A random fit assignment strategy is used with a more robust modulation technique (QPSK) to exploit the next higher indexed spectrum slot which suffers larger dispersion effect. Longer light path requests are assigned to lower indexed spectrum slot (lower dispersion slots) using BPSK modulation technique, while shorter light path requests are sent to next higher indexed spectrum slot (greater dispersion slots) using QPSK modulation technique capturing the dispersion sensitive technique. The results show that the proposed technique achieves a minimal bandwidth blocking probability (BBP) of 0.048, Eye opening Penalty (EOP) of 45.45 dB and Quality Factor of 3.889 and B.P compared with other First Fit (FF) and Random Fit (RF) spectrum allocation schemes.