Dell Technologies recommends using a dual-switch configuration with VLT, as shown in the figure below.
In a dual-switch topology, each VxRail node has one or more connections to each of the two leaf switches providing redundancy at the NIC and switch levels. When VLT is used, the switches are connected with a VLT interconnect (VLTi).
VLT synchronizes ARP, MAC tables, and IPv6 neighbors between the VLT peers and makes the switch pair appear as one logical unit to connected devices.
VLT provides the following benefits:
- Provides a loop-free topology and eliminates STP-blocked ports
- Optimizes the use of all available uplink bandwidth
- Guarantees fast convergence if either a link or a device fails
- Provides link-level resiliency
- Assures high availability
- Allows a single device to use a LAG across two upstream switches
- Provides Layer 2 multipathing