[Beowulf] Сlos network vs fat tree

[Mikhail Kuzminsky]

Sorry, is it correct to say that fat tree topology is equal to 
*NON-BLOCKING* Clos network w/addition of "uplinks" ? I.e. any 
non-blocking Clos network w/corresponding addition of uplinks gives 
fat tree ?

I read somewhere that exact evidence of "non-blocking" was performed 
for Clos networks with >= 3 levels. But most popular Infiniband fat 
trees has only 2 levels.

(Yes, I know that "non-blocking" for Clos network isn't "absolute" 
:-))

Mikhail