Abstract: A label-switching and control interface for asynchronous fast-packet switching consisting of a set of label-switching and cell-processing units controlled by a suitable control unit. The units operate at each multiplex level in real time thanks to a microprogrammed logic requiring the control processor intervention only at the connection set-up/release. The units implement the low levels of the flow control algorithms necessary to conveniently exploit the advantages of the techniques. The label becomes indicative of a virtual circuit which is allotted only locally to the call, annulling thus the necessity of very extensive labels, while the parameters which characterize the connection which uses a particular label are stored in the unit itself.