Regeneration Sites Selection and Regenerator Assignment Strategies for Translucent Elastic Optical Networks: Survey and Analysis

Elastic Optical Networks (EONs) form the backbone of the present day Internet. In Translucent EONs (T-EONs), optical signals are propagated beyond their transparent reach and so in order to maintain the desired Quality of Transmission (QoT) level, the signals have to undergo 3R (re-shaping, re-timing and re-amplification) regeneration at some nodes designated as regeneration sites, also called regenerators. So identification of regenerators is an important problem and is known as Regeneration Site Selection (RSS) problem. Once the regenerators are identified, an important problem is the assignment of optical signals to these regenerators to meet various objectives of the network operator such as minimizing total used spectrum, total number of regenerations etc. and is known as the Regenerator Assignment (RA) problem. In this paper we extend two RSS algorithms originally designed for traditional translucent Wavelength Division Multiplexed (WDM) optical networks to make them applicable for Orthogonal Frequency Division Multiplexing (OFDM) based T-EONs. We further study and analyses two RA algorithms. In addition, we present a survey of the various RSS and RA strategies for T-EONs available in the literature and thereby identify the future scope of research.