Advantages of hybrid input/output wavelength conversion in optical packet switches

In this paper, we propose a new Optical Packet Switching Architecture referred to as Shared Per Input/ Output Line ( SPIOL) in which Wavelength Converters, used to solve output packet contentions, are shared per input and per output line. In this architecture, packets needing conversion can be wavelength translated by converters placed on output lines or by converters placed on input lines. We introduce and discuss the analytical and simulation models we used to evaluate the performance of the architecture in question when a simple control algorithm, referred to as Random Algorithm, is adopted. The proposed architecture performance is compared to that of two other architectures referred to as Shared Per Input Line ( SPIL) and Shared per Output Line ( SPOL), which share converters per output line only and per input line only, respectively. The comparison is carried out under symmetric and asymmetric traffic scenarios. The obtained results show that in some cases the SPIOL architecture allows for a saving in the order of 20% and 30% with respect to the SPIL and SPOL architectures, respectively.