Partitioned Switching Arrays

Known switching arrays service subscribers in either a blocking or a totally nonblocking manner. The first part of this paper describes a method of modifying totally nonblocking arrays to service a group of subscribers, some of which will be given nonblocking service while the rest will be given service at a prescribed blocking probability. It is shown that the resultant crosspoint saving compared with the totally nonblocking case is significant when the subgroup receiving nonblocking service is limited. The method used is illustrated for 3- and 5-stage symmetrical arrays and may be extended to arrays having a greater number of stages. It is then demonstrated how any number of subscriber groups can be serviced with different specified blocking probabilities by such arrays, which are called partitioned switching arrays. An example is included for a partitioned array affording three grades of service.