On the effect of spectrum assignment policies in the efficiency of non-disruptive defragmentation techniques

New techniques for defragmenting spectrum on demand without affecting live traffic and not requiring transponder duplication have been recently proposed. However, the efficiency of these techniques is limited by the network state resulting from the planning algorithms used. In this context, we address the comparison between two retuning techniques, push-pull and hop tuning, and their relationship with different planning policies regarding demand ordering and spectrum assignment. The comparison between the push-pull and hop tuning techniques required the development of efficient heuristic algorithms to obtain results quickly over multiple network topologies and initial planning conditions. These algorithms aim to “clean up” the spectral fragments in the network and they can be applied periodically to restore the spectral efficiency of the network. In this paper we present a planning workflow, in order to evaluate the performance of non-disruptive defragmentation techniques for the various network states given by each planning strategy. The results of this analysis highlight the most suitable policy guidelines, suggesting which planning methods are most suitable when non-disruptive defragmentation algorithms are available in the network operation stage.