Dimensioning Models of Shared Resources in Optical Packet Switching Architectures

In the paper the comparison of some Optical Packet Switching architectures is carried out. The proposed architectures use the wavelength conversion technique to solve the packet contention problem and all of them share the wavelength converters needed in order to wavelength shift the arriving packets. In particular two architectures are considered: the Shared Per Output Line (SPOL) and the Shared Per Input Line (SPIL) architectures in which the wavelength converters are shared per output and output fiber respectively. The packet loss probability of the proposed architectures is evaluated as a function of the used number of wavelength converters by means of analytical models validated by simulations. The obtained results show that the SPIL architecture allow to obtain a larger saving of wavelength converters with respect to the SPOL architecture. In unbalanced offered traffic condition the SPIL architecture allows to save a number of wavelength converters in the order of 50% more than the SPOL architecture.