This topology was introduced to further reduce the amount of links
while maintaining a high bandwidth for local communications. To model
this in SimGrid, pass a ``topology="DRAGONFLY"`` attribute to your
-cluster.
+cluster. It's based on the implementation of the topology used on
+Cray XC systems, described in paper
+``Cray Cascade: A scalable HPC system based on a Dragonfly network`` :
-.. literalinclude:: ../../examples/platforms/cluster_dragonfly.xml
- :language: xml
+System description follows the format ``topo_parameters=#groups;#chassis;#routers;#nodes``
-.. todo::
+For example, ``3,4 ; 3,2 ; 3,1 ; 2``:
+
+- ``3,4``: There are 3 groups with 4 links between each (blue level).
+ Links to nth group are attached to the nth router of the group
+ on our implementation.
+- ``3,2``: In each group, there are 3 chassis with 2 links between each nth router
+ of each group (black level)
+- ``3,1``: In each chassis, 3 routers are connected together with a single link
+ (green level)
+- ``2``: Each router has two nodes attached (single link)
- Add the image, and the documuentation of the topo_parameters.
+.. image:: ../../examples/platforms/cluster_dragonfly.svg
+ :align: center
+
+.. literalinclude:: ../../examples/platforms/cluster_dragonfly.xml
+ :language: xml
Final Word
..........
