Abstract: Aiming at solving the disadvantages in the SDL protocol, we study and modify the protocol mechanism,which enhances the flexibility in carrying the packets of various network layer protocol and improves the ability of error correction.We research the error check and error correction of CRC and the application of using MPLS labels in the SDL protocol. Furthermore, we provide a method of CRC correction and application of using MPLS labels in the SDL protocol.Finally,we present a scheme of realizing the SDL protocol.

Key words: communication protocols, SDL, MPLS, CRC