vSphere 6.0 introduces Enhanced Linked Mode, which links multiple vCenter Server systems by using one or more Platform Services Controllers. This allows you to view and search the inventories of all linked vCenter Server systems within the vSphere Web Client. In a cross-vCenter NSX environment, Enhanced Linked Mode allows to you manage all NSX Managers from a single vSphere Web Client.

In large deployments where there are multiple vCenter Servers, it might make sense for you to use Cross-vCenter NSX with Enhanced Linked Mode for vCenter. These two features are complementary but separate from each other.

In cross-vCenter NSX, you have a primary NSX Manager and multiple secondary NSX Managers. Each of these NSX Managers is linked to a separate vCenter Server. On the primary NSX Manager, you can create universal NSX components (such as switches and routers) that are viewable from the secondary NSX Managers.

When the individual vCenter Servers are deployed with Enhanced Linked Mode, all of the vCenter Servers can be viewed and managed from a single vCenter Server (sometimes called a single pane of glass).

Thus, when cross-vCenter NSX is combined with Enhanced Linked Mode for vCenter, you can view and manage any of the NSX Managers and all of the universal NSX components from any of the linked vCenter Servers.

Enhanced Linked Mode is not a prerequisite or requirement for cross-vCenter NSX. Without Enhanced Linked Mode, you can still create cross-vCenter universal transport zones, universal switches, universal routers, and universal firewall rules. However, without Enhanced Linked Mode in place, you must log in to the individual vCenter Servers to access each NSX Manager instance.

For more information about vSphere 6.0 and enhanced linked mode, see https://blogs.vmware.com/consulting/2015/03/vsphere-datacenter-design-vcenter-architecture-changes-vsphere-6-0-part-1.html.

If you decide to use Enhanced Linked Mode see the vSphere 6.0 Installation and Setup Guide http://pubs.vmware.com/vsphere-60/topic/com.vmware.vsphere.install.doc/GUID-7C9A1E23-7FCD-4295-9CB1-C932F2423C63.html or the vSphere 6.0 Upgrade Guide http://pubs.vmware.com/vsphere-60/topic/com.vmware.vsphere.upgrade.doc/GUID-18B7B4BB-C24A-49CD-AE76-13285157B29F.html for the latest requirements for vSphere 6.0 and Enhanced Linked Mode.