
new optical header is inserted (and the old deleted) before the packet exits to the
network. OPS requires the use of more demanding subsystems (than OBS) with
intrinsic intelligence to realize adequate packet processing and routing on the fly.
The main challenges in OPS are the implementation of the optical header proces-
sing mechanism, the development of an intelligent switch controller, the realiza-
tion of ultrafast switching in nanoseconds timescale, and the exploitation of
buffering mechanisms to reduce packet blocking.
A common realization of a switch node is illustrated in Figure 15.17, which
shows a possible switch fabric but does not include ...