HPC fabric topology

•  ExascaleHPC Fabric Topology

Topologies –Fat Tree Example

Torus Topology

Mesh or 3DTorus

▪Mesh –each node is connected to 4 other nodes: positive and negative X and Y axis

▪3Dmesh –Each node is connected to 6 other nodes: positive and negative X, Y and Z axis

▪2D/3Dtorus –The ends of the 2D/3Dmeshes are connected

Dragonfly+ Topology

What is Dragonfly Topology?

Dragonfly is a hierarchical topology with the following properties:

Several “groups”, connected together using all to all links▪The topology inside each group can be any topology

▪Focus on reducing the number of long links and network diameter to reduce total cost of network

▪Requires Adaptive Routing to enable efficient operation

There are Different Dragonfly Topologies Options

Dragonfly+ Topology

▪Several “groups”, connected using all to all links

▪The topology inside each group can be any topology

▪Reduce total cost of network (fewer long cables)

▪Utilizes Adaptive Routing to for efficient operations ▪Simplifies future system expansion 

Future Expansion of Dragonfly+ Based System

▪Dragonfly+ is the only topology that allows system expansion at zero cost

▪While maintaining bisection bandwidth

▪No port reservation

▪No re-cabling

Dragonfly+ Simplifies Scale Deployment and Cost

http://www.hpcadvisorycouncil.com/events/2019/APAC-AI-HPC/uploads/2018/07/Exascale-HPC-Fabric-Topology.pdf