Performance analysis of multi-fiber all-optical switches employing fixed-input/tunable-output wavelength converters

Abstract

A Multi-fiber all-optical switch which employs wavelength converters with fixed input wavelength is presented. Being the converters tuned over a fixed input wavelength, each one is shared by channels on the same wavelength, so the resulting architecture is called shared-per-wavelength. Here the space switching matrices are simpler with respect to similar switching architectures proposed in the past (i.e. shared-per-node ones) leading to easier and less costly implementation. Moreover, fixed-input/tunable-output converters are expected to be less costly than tunable-input/tunable-output ones. A scheduling algorithm to forward optical packets in synchronous scenario and an analytical model to evaluate performance of the shared-per-wavelength architecture are presented. The analytical model is validated against simulation and the results show good accuracy in most cases of interest for optical switch design

Packet loss analysis of shared-per-wavelength multi-fiber all-optical switch with parallel scheduling

“…This is due to the negative correlation of the number of conversions needed for the various OIs and this is neglected in the analytical models. Results obtained with the model proposed in Section 4.3 agree better with the simulation than that of the analytical model illustrated in [12], especially for high values of load. This is a consequence of the more accurate evaluation of p W OI;k ðkÞðk ¼ 0; 1; .…”

“…The confidence interval of all simulations is at 95% less than or equal to 5% of the mean. [12]. Note that there is a difference among the simulation and the analytical results in the multi-fiber case and both the analytical models overestimate the PLP obtained by simulation.…”

“…A reduction in the computational complexity is obtained through a parallelized organization of the SA, while a sequential description of the SA can be found in [12]. The SA consists of three phases sequentially executed at each time slot and named: Initialization (INI), output wavelength channel assignment (OWCA), Wavelength TWC Assignment (WTA).…”

“….Þ, being the probabilities of the number of conversions needed by the packets arriving on a generic wavelength k and directed to a generic OI. In fact, conversely to the model proposed in [12], the model in this paper considers that in the multi-fiber case no wavelength conversions are needed for the packets lost due to the lack of output wavelength channels. Also the proposed model is less precise when the negative correla- 0 32 64 96 128 160 192 224 256 288 320 352 384 416 448 tion of the number of conversion requests is relevant (in particular with switch dimensioning with low F and high M) as already shown in [12] for the previous model.…”

“…It is compared with results coming from a previous analysis approach proposed in [12] and with simulation results, showing some improvements in model accuracy.…”