Optical data network based on the switchless concept: Analysis and dimensioning

The "switchless" all-optical network aims to provide a future single-layer, advanced transport architecture on a national scale. The single-hop, share d-access network employs time and wavelength agility (a WDMA/TDMA scheme), using fast tuneable transmitters and receivers, to set up individual custom er connections through a single wavelength router, which is suitably replic ated for resilience. While in a recent paper we reported the analysis and d imensioning of a switchless network assuming just the telephone traffic, we provide in this paper a new model, which contains innovative elements, and report original results assuming to deal with data traffic of two differen t types: constant bit rate (CBR) and variable bit rate (VBR). The innovatio n is based on the fact that the model considers more traffic flows with dif ferent traffic requirements (e.g., bandwidth, duration) as input to a group of time-slot connections on the same wavelength between two passive optica l networks (PONs). We obtained analytical expressions of the main traffic c haracteristics (loss probability, throughput and overflowing traffic) both for the primary group of time-slots and for the secondary group of time-slo ts, to which the overflowing traffic streams enters. Moreover, we show that the innovative network structure, i.e., use of a pas sive wavelength router node (PWRN), works also perfectly with more differen t traffic streams. The analytical model presented in this paper has been compared with a simul ation model. The comparison has revealed very good agreement. Relevant netw ork cases are considered, and the dimensioning of the network in such cases is reported, in terms of the key network parameters, loss probability and throughput.