Virtual network-aware DRS is a new feature that was introduced in vSphere 6.5, where DRS now also considers the network utilization when it generates the migration recommendations. If a host has Transmit (Tx) and Receive (Rx) rates of utilization of the connected physical uplinks that's greater than 80%, the VM won't be placed on that host. Network utilization is an additional check to evaluate whether a specific host is suitable for the VM.