Scheduling of online traffic in fragmentation aware energy efficient and survivable elastic optical networks

Abstract

Orthogonal frequency division multiplexing (OFDM) based elastic optical network newline(EON) has become one of the most emerging and promising standards for optical networks newlinedue to its immense bandwidth utilization capability of the optical fibre, which is newlineof the order of 50 Terabits/sec. As the optical network can support the continued demands newlinefor communication bandwidth, it has emerged as the backbone technology for newlinelarge bandwidth data transmission using optical signals and is considered a promising newlinetechnology nowadays. Selection of route and allocating the requisite spectrum for a newlineconnection is known as the routing and spectrum allocation (RSA) problem in EONs. newlineWhile serving a connection request in EONs, three constraints (spectrum contiguity newlineconstraint, spectrum continuity constraint, and non-overlapping constraint) need to newlinebe satisfied. newlineThe capacity of fibre links in optical networks is further increased in space division newlinemultiplexing based elastic optical network, also known as SDM-EON, owing to its newlinecapability of accommodating multiple cores in a single fibre link. The process of newlinedetermining the route, spectrum to be allocated, and core(s) to be selected for a newlinecommunication request is named as routing, spectrum and core assignment (RSCA) newlinein SDM-EONs. Due to the presence of spectrum of same frequencies in adjacent newlinecores, inter-core crosstalk generates which distorts the quality of the optical signal, newlineand this crosstalk issue needs to be taken care of while allocating spectrum in the newlineselected paths. In addition to the existing above-mentioned three constraints for newlineEONs, one additional constraint for RSCA in SDM-EONs is the crosstalk constraint newlinewhich demands the value of crosstalk generated to remain below some threshold value. newlineTraffic nature can be broadly classified as follows: Offline and online. Offline newlinetraffic are known in advance, and they are supposed to stay in the network for a newlinelong time. Online traffic is not known earlier, and it arrives in a busy network, and newlinethe requisite spectrum needs to be allocated