In this paper, two different paradigms to realize a scalable all-optical packet switch with label swapping will be reviewed. The two paradigms are based on wavelength routing switch and space routing switch. All the functions required for switching the packets, namely, the label processor, the label rewriter, and the optical switch, are based on all-optical signal processing with no electronic control. This allows for very fast processing time and potential photonic integration of the systems. We report, for both techniques, experimental results showing the routing operation of the 160-Gb/s packets and beyond. We will discuss and compare both techniques in terms of devices and bit-rate scalability, power consumption, power penalty performance, and cascadability as key parameters for the realization of an all-optical packet switch.