Stage count - is number of devices I need to pass through in order to get from source to the destination.

Clos fabric is a non-planar graph - there is no way to draw all those connections on a flat plane without crossings.

5-stage fabrics type:

• Fat tree
• Benes
• Butterfly

Over-subscription - is the ratio between total bandwidth offered to workloads and to total available fabric bandwidth.

Total Edge port count = spine ports * over-subscription * break-out ration.