<platform version="4.1">
<!-- This is an example for a fat tree cluster.
This is taken from figure 1/ b/ of the paper "D-Mod-K Routing Providing on-Blocking Traffic for Shift Permutations on
- Real Life Fat Trees" available at webee.technion.ac.il/publication-link/index/id/574
+ Real Life Fat Trees" available at http://webee.eedev.technion.ac.il/wp-content/uploads/2014/08/publication_574.pdf
This defines a two levels fat-tree, with 4 leaf switches connected to 4 nodes each and 2 core switches connected to
each leaf switch by two cables -->
