Home > Networking Solutions > Converged and Hyperconverged Solutions > VxRail Networking Solutions > Guides > VMware Cloud Foundation on VxRail Multirack Deployment Using BGP EVPN - Part 2 of 2 > Underlay network connections
Figure 14 shows the wiring configuration for the six switches that include the leaf-spine network. The solid colored lines are 100 GbE links, and the light blue dashed lines are two QSFP28-DD 200 GbE cable pairs that are used for the VLT interconnect (VLTi). The use of QSFP28-DD offers a 400 GbE VLTi to handle any potential traffic increases resulting from failed interconnects to the spine layers. As a rule, it is suggested to maintain at minimum a 1:1 ratio between available bandwidth to the spine and bandwidth for the VLTi.
Figure 14. Physical switch topology
Note: All switch configuration commands are provided in the file attachments. See Attachments for instructions on accessing the attachments.