Comprehensive Comparison of VNE Solutions Based on Different Coordination Approaches

For the evaluation of our experimental results we used the following performance metrics. The acceptance ratio (AR) describes the number of VNRs that could be completely embedded by an embedding algorithm, divided by the total number of processed VNRs. To avoid any overly simplifications we should mention that the statement, the higher the AR the more efficient the embedding strategy, can be proven as rather unidimensional. The cost-revenue measurement (COSTREV) represents the relationship between the proportion of cost spent in the SN and the revenue that has been eventually mapped. However, when multiple sets of VNRs included in the mapping process, failed to be successfully embedded by the algorithms, the embedding cost depicted by the overall spent substrate resources, is going to be substantially low, determining a respectively low COSTREV value. In this context, the COSTREV metric is not a good indicator of the network mapping quality. That’s why this metric can be modified, multiplying it by the percentage of mapped revenue (CR*MR). The number of the embedded virtual nodes to the total number of the residual substrate nodes that actively serve the mapped VNs, is denoted by the active node stress metric (ANSTRESS). The running time (RT) is the time spent by each embedding process in order to achieve a complete and successful VNR mapping.