Improving signaling recovery in shared mesh optical networks

Current restoration signaling is a two-phase messaging procedure between the sender and the receiver and depends heavily on the message propagation delays during the recovery process and the cross-connect switching times. Offset time (OT) based restoration was proposed in [C. Assi, Y. Ye, S. Dixit, M. Ali. Control and management protocols for survivable optical mesh networks, IEEE Journal of Lightware Technology, November 2003.] to address the impact of these parameters and upper bound (OT-UB) expressions were derived. However, our closer investigation showed that as the network conditions change (e.g. increasing the number of wave-length channels per link) the benefits this restoration paradigm offer rapidly diminish, thereby rendering the argument of avoiding conventional restoration signaling inappropriate. In this paper, we propose a more accurate model to estimate the OT of each failed connection using a time-driven scheduling procedure. We also study the applicability of the proposed recovery protocol under double link failures assumption and we propose extensions to the protocol. We evaluate our proposal through simulation experiments and we show that substantial restoration gain can be achieved under varying network conditions.