Cselt-centro Studi E Laboratori Telecomunicazioni S.p.a.

Telecom Italia

Paolo Mattone

Carlo Demichelis

Massimo Sassi

Paolo Mancini

Alessandro Zappalorto

Laura Apicella

Isabella Melli

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. Each unit switches the label characterizing the connection on the node input multiplex, with that whereby it is characterized on the output multiplex and at the same time associates, with each cell, the information necessary to multiplex switching which is then carried out in a self-routing network. The cells processed in this way by each unit of the set are statistically multiplexed in an asynchronous way and sent to a connection network termination. Such a termination serves a plurality of asynchronous multiplexes, which can be at a different frequency from each other and more particularly it is worth noting that each label-switching unit does not have its own operating frequency, but automatically takes up that of the asynchronous multiplex to which it is connected.

Label-switching and control interface for asynchronous fast-packet

An interface interposed between a PCM data terminal and a processor comprises a bus accessor dialoguing with the processor, input and output circuitry coupled to the terminal, and intervening logic circuits and data stores designed to supply the processor in a time-division mode with preprocessed messages received or to be transmitted over a multiplicity of channels. The interface is operable according to dialogue procedures of HDLC type such as those corresponding to CCITT recommendations X25, X75 and N. 7, with switchover from one protocol to another.

Multichannel interface linking a PCM line with a processor

Growing community of inventors

Turin, Italy

Paolo Mattone