Multicast connection scheduling in time:space:time switching fabrics

12 Nth 12N th 12N Multicast call blocking is reduced in TST switch fabrics with the aid of an m-entry data structure. Each entry corresponds to one of m timeslots, and has 2n sub-entries corresponding to n input ports and n output ports. An N-cast call X:(y→z, z. . . z) is representable by associating a selected entry's yinput sub-entry with z, z, . . . zof the selected entry's output sub-entries. Upon receipt of a call, the data structure entries are sequentially examined to detect the first entry for which a yinput sub-entry is unused and z, z, . . . zoutput sub-entries are unused. If such an entry is detected, the call is scheduled for transmission in the corresponding timeslot. If there is no such entry and if N=1 the call cannot be scheduled; but, if N>1 the call is divided into two or more calls and an attempt is made to schedule them as above.