Optical Packet Switching

On the design of asynchronous optical packet switch architectures with shared delay lines and converters

“…-Wavelength Conversion. Wavelength conversion is an effective method for contention resolution without experiencing the latency and packet rescheduling incurred from optical FDLs [1,11,[15][16][17]. In this method, when two or more packets contend for the same output port and wavelength, the wavelengths of contended packet are converted to free wavelengths on the desired output, thus resolving the contention (See Fig.…”

“…Optical buffering using FDLs is the most straightforward method for resolving contention in OPS architectures [11,13,14]. In optical buffering, when contention occurs, one of the contended packets is forwarded to the output port, while the rest of the packets are sent to the appropriate FDLs in the switch.…”

“…Contention occurs when two or more packets arrive on two or more input ports with same wavelength require the same output port at same time. The following summarizes key contention resolution techniques for OPS [1,11]:…”

“…This leads to lower switch utilization and higher switching delays. Three known techniques were proposed to deal with contention in OPS architectures, namely, optical buffering via fiber delay lines (FDLs), wavelength conversion, and space deflection [11]. These techniques can be combined or used in isolation to construct OPS architectures with a trade-off between complexity and performance.…”

“…Generally speaking, optical packet switching networks can be classified into two main types: slotted networks (synchronous) and unslotted networks (asynchronous) [1,11]. In slotted networks, all packets occupy the same time slot.…”