SNCP is commonly used for redundancy in today’s networks. Let’s see what is going on with SNCP and detail it a little bit more.
SNCP (Sub-Network Connection Protection) is a dedicated protection mechanism that can be used
to protect a portion of a path (between two NE) or the full end-to-end path.
Each transmitting signal node is permanently connected (bridge) in the main traffic direction (i.e.
clockwise) and in the protected traffic direction (i.e. counter clockwise). The Tx signal reaches
destination through two different paths, thus enabling the node receiving it to select the best one.
Two types of SNCP are possible:
* SNCP/I (Inherent monitoring) that switches on SSF criteria (AU-AIS or AU-LOP for HVC and
TU-LOP or TU-AIS for LVC).
* SNCP/N (Non-intrusive monitoring) where POH is monitored by the POM enabled before the
matrix. The switches criteria are SSF and one or more of ExBER, TIM, UNEQ, SD.
Two operating modes can be selected for single VC SNCP:
* Revertive (the signal is switched back into the working channel, after recovery of the fault)-In
* The revertive operation the “Wait time to restore” (WTR) is fixed at 5 min.