Growable packet switch architecture

Abstract

This invention is large N×N packet switch, formed using a plurality of smaller packet switches. The invention comprises an N input, L output interconnect fabric (L>N), and a plurality of J×K smaller packet switches (J>K). Each of the J inputs to each packet switch is connected to a separate one of the L outputs of the interconnect fabric, and each of the K outputs from each packet switch is connected to a destination equipment. In operation, packets are received at the N inputs to the interconnect fabric, and each packet is routed to one of the inputs of the packet switch associated with the destination user equipment for the packet. Simultaneous packets, up to J in number, are routed to separate inputs of a particular packet switch for distribution to their respective destinations, while all other simultaneous packets destined for user equipments associated with the same packet switch are lost, the probability of such a loss being acceptably small.

We claim: .[.1. A packet switching arrangement comprising: 
     
        communications path for each data packet..]. .Iadd.4.  A packet switching arrangement comprising: (i) an interconnect fabric comprising,   a plurality of input ports for receiving data packets,   a plurality of groups of output ports, each group comprising a separate number of one or more output ports, each of said output ports for supplying data packets as an output and each output port of a particular group being assigned to a common destination which is different from a destination assigned to output ports of at least another group, where the separate number of output ports comprised in a group of output ports may be the same as or different from the number of output ports comprised in other groups of output ports, at least one of the groups comprising more than one output port, and   means for mapping each received data packet to a group of output ports and for mapping concurrently received data packets destined for a particular one of said destinations to respective output ports in a particular group assigned to the particular destination, said means for mapping including means for establishing a separate communications path from each separate input port at which each data packet is received to a separate output port of the group of output ports to which the data packet is mapped and for transmitting each data packet over the separate established communications path, (a) a plurality of input modules, each input module comprising (1) at least one input, each input being coupled to a separate interconnect fabric input port, (2) a plurality of outputs and (3) means for selectively connecting any input to any output for forming a first portion of the established communications path for each data packet, (b) a plurality of intermediate modules, each intermediate module comprising (1) a plurality of inputs, each input is coupled to a separate input module output, (2) a plurality of outputs, each output being coupled to a separate interconnect fabric output port of a predetermined number of groups of interconnect fabric output ports, and (3) means for selectively connecting any intermediate module input to any intermediate module output for forming a second portion of the established communications path for each data packet; and   (ii) a plurality of output packets switches, each output packet switch being arranged to receive data packets from a separate group of interconnect fabric output ports and route the data packets to one or more destinations..Iaddend. .Iadd.5. A packet switching arrangement as defined in claim 4 wherein said plurality of interconnect fabric input ports includes a first number of of input ports and said plurality of interconnect fabric output ports includes a second number of output ports   
     
     
        larger than said first number of input ports..Iaddend. .Iadd.6.  A packet switching arrangement as defined in claim 5 wherein said data packets are transported through said interconnect fabric on a circuit switched basis..Iaddend. .Iadd.7. A packet switching arrangement as defined in claim 5 wherein each of said plurality of packet switches includes a plurality of input ports and a plurality of output ports..Iaddend. .Iadd.8. A packet switching arrangement as defined in claim 7 wherein said plurality of packet switch input ports includes a third number of input ports and said plurality of packet switch output ports includes a fourth number of output ports fewer than said third number of input ports..Iaddend. .Iadd.9. A packet switching arrangement as defined in claim 4 wherein said interconnect fabric further includes means for discarding those data packets received during a current time slot and in excess of the separate number of output ports comprised in a particular group of output ports for which those excessive packets are destined..Iaddend. .Iadd.10. A packet switching arrangement as defined in claim 4 wherein said interconnect fabric further includes means for storing until a subsequent time slot, those data packets received during said current time slot and in excess of the separate number of output ports comprised in a particular group of output ports for which those 
     
     
        excessive packets are destined..Iaddend. .Iadd.11.  A packet switching arrangement comprising: (i) an interconnect fabric comprising,   a plurality of input ports for receiving data packets,   a plurality of groups of output ports, each group comprising a separate number of one or more output ports, each of said output ports for supplying data packets as an output and each output port of a particular group being assigned to a common destination which is different from a destination assigned to output ports of at least another group, where the separate number of output ports comprised in a group of output ports may be the same as or different from the number of output ports comprised in other groups of output ports, at least one of the groups comprising more than one output port, and   means for mapping each received data packet to a group of output ports and for mapping concurrently received data packets destined for a particular one of said destinations to respective output ports in a particular group assigned to the particular destination, said means for mapping including means for establishing a separate communications path from each separate input port at which each data packet is received to a separate output of the group of output ports to which the data packet is mapped and for transmitting each data packet over the separate established communications path, said means for establishing and for transmitting including (a) a plurality of input modules, each input module comprising (1) at least one input, each input being coupled to a separate interconnect fabric input port, (2) a plurality of outputs, and (3) means for selectively connecting any input to any output for forming a first portion of the established communications path for each data packet, and (b) a plurality of intermediate modules, each intermediate module comprising (1) a plurality of inputs, where each input is coupled to a separate input module output, (2) a plurality of outputs, each output being coupled to a separate interconnect fabric output port of a predetermined number of groups of interconnect fabric outputs and (3) means for selectively connecting any intermediate module input to any intermediate module output for forming a second portion of the established communications path for each data packet; and   (ii) a plurality of output packets switches, each output packet switch being arranged to receive data packets from a separate group of interconnect fabric output ports and route the data packets to one or more destinations..Iaddend.