To enable migration across vCenter Server instances, your system must meet certain requirements.
The source and destination vCenter Server instances and ESXi hosts must be 6.0 or later.
The cross vCenter Server and long distance vMotion features require an Enterprise Plus license. For more information, see http://www.vmware.com/uk/products/vsphere/compare.html.
Both vCenter Server instances must be time-synchronized with each other for correct vCenter Single Sign-On token verification.
For migration of compute resources only, both vCenter Server instances must be connected to the shared virtual machine storage.
When using the vSphere Web Client, both vCenter Server instances must be in Enhanced Linked Mode and must be in the same vCenter Single Sign-On domain so that the source vCenter Server can authenticate to the destination vCenter Server.
For information about installing vCenter Server in Enhanced Linked Mode, see the vSphere Installation and Setup documentation.
If the vCenter Server instances exist in separate vSphere Single Sign-On domains, you can use vSphere APIs/SDK to migrate virtual machines. For more information, see the VirtualMachineRelocateSpec data object in the vSphere Management SDK Guide.