  The main issue in the optical transmission is switching speed. The optical
packet switching faces many significant challenges in processing and buffering.
The generalized multilevel protocol switching seeks to eliminate the
asynchronous transfer mode and synchronous optical network layer, hence the
implementation of IP over WDM (wave length division multiplexing). Optical
burst switching attempts to minimize the need for processing and buffering by
aggregating flow of data packets in to burst. In this paper there is an
extensive overview on current technologies and techniques concerning optical
switching.
