Simple data link (SDL) protocol

摘要

A simple point-to-point data link protocol (SDL) is defined which is based on the use of a length indicator field and an error check field, rather than a flag, for performing packet boundary recovery in a receiver. In an embodiment of the invention, an SDL transmitter transmits SDL packets comprising a header and a variable length payload. The SDL header comprises a length indicator (LI) field, a type field and a cyclic redundancy check (CRC) field. For receiving these transmitted SDL packets, SDL supports the use of a self-synchronization/self-delineation technique in the receiver. The receiver performs self-delineation as a function of the LI field, and performs self-synchronization, or packet recovery, as a function of both the LI field and the header CRC field. In particular, in performing packet recovery, the receiver performs a CRC check over each received SDL packet header and synchronization is declared after N correct checks, e.g., N = 4. The SDL receiver operates in a hunt mode when performing synchronization, and a normal mode when synchronization has been accomplished.