Johns Hopkins University

Yuanyuan Yang

Gerald M Masson

A controller for a nonblocking broadcast switching network comprising an input stage, an output stage, and a middle stage. The input stage has N.sub.1 or n.sub.1 r.sub.1 input ports and r.sub.1 switches, where n.sub.1 .gtoreq.2 and r.sub.1 .gtoreq.1 and are integers. The network also includes an output stage. The output stage has N.sub.2 or n.sub.2 r.sub.2 output ports and r.sub.2 switches, where n.sub.2 .gtoreq.2 and r.sub.1 .gtoreq.1 and are integers. There is also a middle stage. The middle stage has m switches, where ##EQU1## The m switches are in communication with the r.sub.1 switches and r.sub.2 switches. The middle stage of m switches has L inputs, where L.gtoreq.r.sub.1 and is an integer, and J outputs, where J.gtoreq.r.sub.2 and is an integer, corresponding to the n.sub.1 input ports and n.sub.2 output ports, x or fewer of the m switches, where 1.ltoreq.x.ltoreq.m, always available to form a connection between an idle input port and a plurality of idle output ports, but no output port is connected to more than 1 input port. In a preferred embodiment, the controller includes a mechanism for determining which middle stage switches are idle at a given time in the network. The controller also includes a mechanism for choosing middle stage switches from only the idle middle stage switches to form a desired broadcast connection between an idle input port and a plurality of idle output ports. Preferably, the mechanism for choosing chooses the minimum number of idle middle stage switches to form the desired broadcast connection.

Controller for a non-blocking broadcast network

The present invention pertains to a nonblocking broadcast switching network. The network comprises an input stage. The input stage has N.sub.1 or n.sub.1 r.sub.1 input ports and r.sub.1 switches, where n.sub.1 .gtoreq.2 and r.sub.1 .gtoreq.1 and are integers. The network is also comprised of an output stage. The output stage has N.sub.2 or n.sub.2 r.sub.2 output ports and r.sub.2 switches, where n.sub.2 .gtoreq.2 and r.sub.1 .gtoreq.1 and are integers. There is also a middle stage. The middle stage has m switches where m is an integer and, where ##EQU1## The m switches are in communication with the r.sub.1 switches and r.sub.2 switches. The middle stage of m switches has L inputs, where L.gtoreq.r.sub.1 and is an integer, and J outputs, where J.gtoreq.r.sub.2 and is an integer, x or fewer of the m switches, where 1.gtoreq.x.gtoreq.min{n.sub.2 -1, r.sub.2 } and is an integer, always available to form a connection between an idle input port and a plurality of idle output ports, but no output port is connected to more than 1 input port. In a preferred embodiment, the controller is comprised of means for determining which middle stage switches are idle at a given time in the network. The controller is also comprised of means for choosing middle stage switches from only the idle middle stage switches to form a desired broadcast connection between an idle input port and a plurality of idle output ports. Preferably, the choosing means chooses the minimum number of idle middle stage switches to form the desired broadcast connection.

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Baltimore, MD, United States of America

Yuanyuan Yang