common part convergence sublayer (ATM) (CPCS)

Common Part Convergence Sublayer (CPCS) is one of two AAL sublayers in the ATM layer model.

The CPCS sublayer is service-independent and is divided into the Convergence Sublayer( CS) and the Segmentation and Reassembling Sublayer( SAR). In CPCS, the data is prepared for transport over the ATM network and the 48- byte user data units ( payload) are generated.

When the payload passes through CPCS, the header and trailer are added.