Evolution of the generalized parallel delta networks towards a photonic switching environment

The nonblocking properties of the generalized parallel delta networks (GPDNs) and their application to the photonic switching environment are discussed. It is demonstrated that the crosstalk due to the switch crossover can be completely avoided by means of a proper dimensioning of the network parameters. A classification of the nonblocking properties is proposed. In particular, a nonblocking condition, called as strong, is defined. It establishes that two paths are not in conflict if they do not share any switching element. The strong nonblocking condition has been considered together with the traditional one. This second condition, called as weak because it is based on the unshareability of the interstage links, is normally applied in the electronic environment. The conditions which have to be satisfied so that a GPDN can be weakly and/or strongly nonblocking are found and demonstrated