De-multiplexing the required spectrum in a traffic demand into multiple non-adjacent granular spectrums for dynamic traffic grooming in EON

Abstract

An elastic light-trail, the advanced version of a traditional light-trail, is one of the most recent dynamic traffic grooming technologies in an elastic optical network. In such networks, Orthogonal Frequency Division Multiplexing (OFDM) is a promising technology to execute the RSA (routing and spectrum assignment) algorithm and implement an elastic light-trail as a result. However, the reconfigurable optical add-drop multiplexers (ROADMs) and bandwidth variable Wavelength Selective Switches (WSSs) are required to implement an optically switched and spectrum varying elastic lightpath. In addition to the hardware equipment mentioned above, Add Drop Couplers (ADC) and optical ON/OFF switches (OS) are required to facilitate elastic light-trail in an elastic optical network. Hereafter, deployment of Add Drop Couplers (ADC) and optical ON/OFF switches incurs a significant network cost to facilitate elastic light-trail implementation. Toward the approach for eliminating this costly hardware setup, we have highlighted the fragmentation problem that occurs in spectrum domain in an optical fiber link. In this problem, the entire spectrum range in an elastic optical link is fragmented into several non-contiguous free spectrum slots at an instance during a data transportation session. In this regard, we have proposed “Multiple multi-hop non-contiguous elastic lightpath - MMNCEL” algorithm, where the required spectrum B of a traffic demand r(s, d, B, T) is sliced into n distinct granular spectrums {b1, b2, … bn} according to the current availability and status of fragmented spectrum slots in an elastic optical link. Moreover, to setup an elastic lightpath, the algorithm allocates the same range of spectrum from every optical link in a route to preserve Spectrum Continuity Constraint (SCC), whereas, at each hop in a multi-hop elastic lightpath the algorithm performs opto-electrical conversion. In this paper, our objective is to achieve maximum network throughput in an elastic optical network without deploying ADC and optical ON/OFF switches. However, in this work, we have investigated optical spectrum utilization efficiency for the proposed MMNCEL, existing elastic light-trail (Multi-hop Elastic Light-trail algorithm - MELT) and elastic lightpath (Multi-hop elastic Lightpath algorithm - MEL), and performed comparison measurements preciously.