The deployment types to consider are as follows:
New Installation
•
Greenfield—Completely new installation of the Cisco Unified Communications System, using no existing equipment.
•Brownfield—Existing Cisco Unified Communications System, which requires an upgrade and migration from a previous system release to the current system release.
Single-Stage Upgrade
•Using existing hardware—All components in the network start at the base release set and all components can be upgraded to the target release set within a single maintenance window.
•Using new hardware (flash-cut or shrink-and-grow)—A parallel network should be built using new hardware and pre-staged with configuration to support the existing production network.
For more information about deployment types, see System Installation and Upgrade for IP Telephony for Small and Medium Business 
.