Evaluation of time-efficiency of disjoint paths calculation schemes

The concept of alternate paths has been shown in the literature to provide fast response of a network to failures of its elements (nodes/links) affecting flows along the primary communication paths. Various approaches have been proposed to reduce the time necessary to redirect the respective flows onto the alternate paths. In this paper, we focus on another important objective, that so far has not received much attention, i.e., reduction of the overall time needed to calculate the set of working and alternate paths. The issue is important e.g., in the case of reactive approaches to survivable routing (if a failure of a network element leads to multiple attempts to determine the respective alternate paths), or when performing the periodic updates of the resilient routing scheme in the global scale. The aim of this paper is to present the analysis of time efficiency of our approach to provide the global set of end-to-end disjoint paths in comparison to the reference Bhandari´s scheme. In particular, after describing the respective examples of our algorithm execution, we show (based on simulations) that it is possible to establish the sets of primary and alternate paths up to 70 times faster, compared to the common existing reference schemes.