The easiest way to measure it is to use the ATA sizing tool. Read this: https://docs.microsoft.com/en-us/advanced-threat-analytics/plan-design/ata-capacity-planning
Basically it is a script that measures the DC for 24 hours and creates an excel spreadsheet. From this spreadsheet you can see in the table in Ata Capacity planning on how much it can take....
From my experience an ESXi host should have more than one phyiscal nic when hosting a lot of vm's. 2-4 nics with 1gb link on each.
Oddvar Moe
https://msitpros.com