Networking Reference
In-Depth Information
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Figure 4.5: Conventional Butterfly Topology (4-ary 3-fly) with 64 nodes. P represents the processor or
the terminals nodes and R represents the switches or the routers. For simplicity, the network injection
ports (terminal ports) are shown on the left while the network ejection ports are shown on the right.
However, they represent the same physical terminal nodes.
path diversity in the topology as there is only a single path between any source and any destination.
This results in poor throughput for any non-uniform traffic patterns. In addition, a butterfly network
cannot exploit traffic locality as all packets must traverse the diameter of the network.
4.3.3 HIGH-RADIX FOLDED-CLOS
A Clos network [ 14 ] is a multi-stage interconnection network consisting of an odd number of
stages connecting input ports to output ports (Figure 4.6 (a)). The Clos network can be created by
combining two butterfly networks back-to-back with the first stage used for load-balancing (input
network) and the second stage used to route the traffic (output network). A Clos network provides
 
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