Core Infrastructure SuitesECI lets you acquire and manage Microsoft’s core infrastructure products under a single agreement. Based on your virtualization needs, you choose whether to license the Core Infrastructure Suite (CIS) Datacenter or Standard Edition, or a mix of both. Either edition offers the same cloud capabilities. The only difference lies in virtualization rights. While each CIS Standard Edition license accommodates the right to manage up to two virtual OSEs (operating system environments), with each Datacenter Edition license the number of virtual OSEs is unlimited