Modelling Standard and Randomized Slimmed Folded Clos Networks

Fat-trees (FTs) are widely known topologies that, among other advantages, provide full bisection bandwidth. However, many implementations of FTs are made slimmed to cheapen the infrastructure, since most applications do not make use of this full bisection bandwidth. In this paper Extended Generalized Random Folded Clos (XGRFC) interconnection networks are introduced as cost-efficient alternatives to Extended Generalized Fat Trees (XGFT), which is a widely used topological description for slimmed FTs. This is proved both by obtaining a theoretical model of the performance and evaluating it using simulation. Among the results, it is shown that a XGRFC is able to connect 20k servers with 27% less routers than the corresponding XGFT and still providing the same performance under uniform traffic.