Optical Burst Switching networks are considered as an important candidate for the future transport networks. Many analysis models of OBS node with FDLs have been proposed recently.  In this paper, we propose a novel retrial queueing model at OBS core node architecture SPL - feed-forward. Blocking probability will be calculated based on Markov multi-dimensional models. Numerical solution values from the proposed analysis method are compared with simulation, as well as between these models.