Switching network

Abstract

A large high capacity switch is provided for a communication network which is constructed from a network of smaller switches. Data is fragmented into fixed sized cells and the cells of a traffic flow are aggregated by grouping cells to form larger yet uniform units of information transfer. The groups are transmitted synchronously and in parallel to increase the effective bandwidth of information transfer.

1 . A method of transporting cells of information of fixed size through a multi-stage Clos network comprising:
 forming groups of cells at a node in any stage of the Clos network except the last stage, each group of size s, and   transmitting the group members through s output ports of the node during a single clock cycle.   
   
   
       2 . The method of  claim 1  wherein a plurality of nodes of the network form groups of cells. 
   
   
       3 . The method of  claim 1  wherein the cells of a group have the same destination. 
   
   
       4 . The method of  claim 3  wherein the destination is a node in the Clos network. 
   
   
       5 . The method of  claim 3  wherein the destination is an egress port of the Clos network. 
   
   
       6 . The method of  claim 1  further comprising holding the cells in a queue until a s number of cells are assembled to create a group. 
   
   
       7 . The method of  claim 1  further comprising transferring the members of a group from one stage of the Clos network to the next substantially simultaneously. 
   
   
       8 . The method of  claim 1  wherein all members of a group pass through a single node in the Clos network and further comprising reassembling the group at said single node. 
   
   
       9 . The method of  claim 8  wherein the group is reassembled with cells of the group placed in the original sequence. 
   
   
       10 . The method of  claim 1  further comprising, when a plurality of cells of a group arrive at a node, enqueuing the cells based on the destination of the cell. 
   
   
       11 . The method of  claim 10  wherein the sequence of the cells' ingress into the network is preserved when the cells are enqueued. 
   
   
       12 . The method of  claim 10  wherein the destination is an egress port of the Clos network. 
   
   
       13 . The method of  claim 10  wherein the destination is another node in the Clos network.