The speed is an important aspect of the current generation of Internet users. Currently WDM based optical fiber technology provides a good solution, still it is insufficient for future growth of cloud data centers, social media applications, online gaming, high definition video streaming and broadcasting, etc. The Elastic Optical Networks (EONs) recently added an energetic research field in the fiber-optic network. The EON is next generation of network that can provide flexibly in spectrum, improved service provisioning and accommodate high bandwidth applications in the single channel. In WDM, the Routing and Wavelength Assignment (RWA) is problem, likewise the EON has Routing and Spectrum Assignment (RSA) problem. In RSA problem the frequency slots (FSs) should allocate in continuity and contiguous manner for every demand request. Many research articles are published over the years to find the new feasible solutions for the RSA problem. This paper presents the recent approaches based on routing and spectrum assignment problem and fragmentation schemes which examines and compare the performance, features, and complexity of the approaches. This paper provides merits and demerits of existing approaches in RSA problem and provides more information about the approaches it will help for feature research.
Joint content placement and lightpath routing and spectrum assignment in CDNs over elastic optical network scenarios
