Switching in core optical networks is currently being performed using high-speed electronic or all-optical circuit switches. Switching with high-speed electronics requires optical-to-electronic (O/E) conversion of the data stream, making the switch a potential bottleneck of the network: any effort (including parallelization) for electronics to approach the optical speeds seems to be already reaching its practical limits. Furthermore, the store-and-forward approach of packet-switching does not seem suitable for all-optical implementation due to the lack of practical optical random-access-memories to buffer and resolve contentions. Circuit switching on the other hand, involves a pre-transmission delay for call setup and requires the aggregation of microlows into circuits, sacriicing the granularity and the control over individual lows, and is ineficient for bursty traf- ic. Optical burst switching (OBS) has been proposed by Qiao and Yoo (1999) to combine the advantages of both packet and circuit switching and is considered a promising technology for the next generation optical internet.