Large fault tolerant packet switch particularly suited for asynchronous transfer mode (ATM) communication

Apparatus for a packet switch comprising:

• "k" substantially identical input modules, wherein each of said input modules provides "n" separate input ports and "m" separate outputs and applies incoming packets from said input ports to said outputs in a first pre-defined fashion, each of said incoming packets having first and second distinct address portions and a data portion therein;
• "k" substantially identical output modules, wherein each of said output modules has "m" separate inputs and provides "n" separate output ports and applies in a second pre-defined fashion data portions of outgoing packets from said inputs to said output ports;
• "m" substantially identical k-by-k cross-point switching circuits (where "k", "m" and "n" are all pre-defined integer values), wherein each of said switching circuits is connected to a corresponding one of the "m" outputs of each of said input modules, all the corresponding outputs having the same numerical ranking, and to a corresponding input to each of said output modules, all of the corresponding inputs having the same numerical ranking, wherein each of said "m" switching circuits comprises:
• means, responsive to the first address portion of each of the incoming packets applied over said corresponding output from any of said "k" input modules, for establishing for said each incoming packet a route through said each switching circuit and over said corresponding output to an addressed one of said "k" output modules;
• and
• wherein each of said "k" output modules comprises means, responsive to, the second address portion contained within a packet applied to said each output module by any of said "m" switching circuits, for applying the data portion contained within said applied packet to an addressed one of the "n" output ports associated therewith.

In a packet switch having a plurality of input modules each providing a plurality of input ports and having a plurality of outputs, a plurality of output modules each having a plurality of inputs and providing a plurality of output ports, and a plurality of cross-point switching circuits each being connected to a corresponding output of each of said input modules and to a corresponding input to each of said output modules, and wherein each of said incoming packets has first and second distinct address portions and a data portion therein, a method for routing packets through said switch comprising the steps of:

• in each input module, applying incoming packets from said input ports thereto to said outputs thereof in a first pre-defined fashion;
• in each output module, applying, in a second pre-defined fashion, data portions of outgoing packets from said inputs thereto to said output ports therefrom;
• in each cross-point switching circuit:
• establishing, in response to the first address portion of each of the incoming packets applied over said corresponding output from any of said input modules, a route for said each incoming packet through said switching circuit and over said corresponding output to an addressed one of said output modules;
• and
• routing a of said each incoming packet over said route as a corresponding one of said outgoing packets to said addressed output module;
• and
• wherein said method further comprises the step, within each of said output modules, of applying, in response to the second address portion contained within said one outgoing packet applied to said each output module by any of said cross-point switching circuits, the data portion contained within said one outgoing packet to an addressed one of the plurality of said output ports associated therewith.

In a packet switch having "k" substantially identical input modules each providing "n" separate input ports and having "m" separate outputs, "k" substantially identical output modules each having "m" separate inputs and providing "n" separate output ports, and "m" substantially identical k-by-k cross-point switching circuits each being connected to a corresponding output of each of said input modules and to a corresponding input to each of said output modules, wherein all the corresponding outputs have the same numerical ranking and all of the corresponding inputs having the same numerical ranking, and wherein each of said incoming packets has first and second distinct address portions and a data portion therein, a method for routing packets through said switch comprising the steps of:

• in each input module, applying incoming packets from said "n" input ports thereto to said "m" outputs thereof in a first pre-defined fashion;
• in each output module, applying, in a second pre-defined fashion, data portions of outgoing packets from said "m" inputs thereto to said "m" output ports therefrom;
• in each cross-point switching circuit:
• establishing, in response to the first address portion of each of the incoming packets applied over said corresponding output from any of said "k" input modules, a route for said each incoming packet through said switching circuit and over said corresponding output to an addressed one of said "k" output modules;
• and
• routing a portion of said each incoming packet over said route as a corresponding one of said outgoing packets to said addressed output module;
• and
• wherein said method further comprises the step, within each of said "k" output modules, of applying, in response to the second address portion contained within said one outgoing packet applied to said each output module by any of said "m" cross-point switching circuits, the data portion contained within said one outgoing packet to an addressed one of the "n" output ports associated therewith.