A. VECD is a Windows Vista Enterprise Edition licensing model for a virtualized desktop infrastructure in which a virtual server runs many virtual machines (VMs) that each run a client OS instance.

VECD is a nonperpetual, subscription-based model that is instance based, as opposed to installation based.

There are two options to license VECD. Both options require that clients have volume-licensing in either an enterprise agreement or select agreement:

  1. If you already have a full PC license, you purchase an annual PC VECD license, which allows an unlimited number of guest OSs. Each licensed client device can access as many as four virtual guests, which can be on separate virtual servers

  2. If you use a thin client and don't have a separate PC license, you purchase an annual subscription that allows an unlimited number of Vista Enterprise OSs or earlier OSs. Once again, as many as four virtual guests can be concurrently accessed.