This paper presents a new approximate analytical recurrent calculation method of the occupancy distribution and the blocking probability in switching networks which are offered multi-service traffic streams generated by Binomial (Engset) & Poisson (Erlang) & Pascal traffic sources (BPP traffic). The method is based on the concept of
. The proposed calculation algorithm is based on the recurrent calculation of blocking probability in subsequent subsystems of the switching network. These calculations involve determination of occupancy distributions in interstage links as well as in the outgoing links. These distributions are calculated by means of the full-availability group model and the limited-availability group model. The results of analytical calculations of the blocking probabilities are compared with the simulation results of 3-stage and 5-stage switching networks.