Modeling impact of ROADM intra-node Add/Drop contention on a single node lightpath blocking performance

We propose an analytical model to evaluate the lightpath blocking performance for a single ROADM node with intra-node add/drop contention, in which the number of lightpaths that can be added/dropped with the same wavelength is limited by the add/ drop contention factor. Different models of traffic load per nodal degree are considered to validate the effectiveness of the analytical model. The simulation results show that the proposed analytical model is effective in predicting the performance for different values of add/drop contention factor C and for variable offered loads at the node. The add/drop contention factor shows an important impact on the lightpath blocking performance and properly raising the contention factor can significantly improve the lightpath blocking performance. When the add/drop contention factor C exceeds a certain level, the performance of a ROADM with intra-node contention is close to that of a contentionless ROADM.