Chuong Dang Thanh, Duc Pham Trung, Thang Doan Van AbstractOptical Burst Switching networks are considered as an important candidate for the futuretransport networks. Many analysis models of OBS node with FDLs have been proposedrecently. In this paper, we propose a novel retrial queueing model at OBS core nodearchitecture SPL – feed-forward. Blocking probability will be