Citrix XenDesktop 4.0

Citrix XenDesktop 4.0 is a set of Citrix technologies which can be used together to dynamically create desktops which can be delivered directly to users computers using streaming or can be accessed remotely from central systems using the Citrix Receiver.

The key components in this solution are:

     •  Citrix Desktop Delivery Controller (Connection Broker)

     •  Citrix Provisioning Server (Provisioning)

Optional components include:

     •  Citrix XenServer (Hypervisor)

     •  Citrix XenApp

Citrix XenServer

Citrix XenServer can provide the hypervisor technology if desktops are to be created in a data centre and then accessed remotely by users. XenServer is based on virtualisation technology acquired from Xen and redeveloped by Citrix.

XenDesktop doesn't need to use XenServer as the hypervisor component, as it's open architecture allows it to be used with other hypervisors from Microsoft (Hyper-V) and VMware (ESX).

Citrix Desktop Delivery Controller

The Citrix Desktop Delivery Controller (DDC) brokers user access to desktops through the integration with existing authentication services such as Microsoft's Active Directory.

The Desktop Delivery Controller monitors the connection state between the users and their desktops and can be configured to select particular desktops or use a 'desktop pool' of similar desktops.

Citrix Provisioning Server

The Citrix Provisioning Server (CPS) allows the creation of multiple desktops from a single desktop image, which can be streamed to a hypervisor such as XenServer or directly to the users computer.

Citrix Desktop Receiver

The Citrix Desktop Receiver is an agent installed on the users computer which provides the ability to display and interact with the virtual desktop environment hosted on the hypervisor, using a remote presentation protocol which is Citrix's Independent Computing Architecture (ICA) protocol.

Desktops which are streamed directly to the users computer don't use the Desktop Receiver but instead boot (PXE) and stream the desktop directly.

Citrix XenApp

Licensing changes made by Citrix allow Citrix XenApp functionality to be available in XenDesktop without the need to purchase additional licenses, with the exception of the VDI edition.

The XenApp functionality is like for like on the edition purchased, so if the XenDesktop Enterprise Edition is purchased then the XenApp functionality is based on XenApp Enterprise Edition.

XenDesktop Licensing

XenDesktop is licensed in either per user or per device mode for all editions, with the VDI edition including an additional concurrent user (CCU) licensing option.

VECD licenses are also required if the desktops delivered to the hypervisor or directly streamed to the user computer are going to based on a Microsoft Windows operating system.

Terminal Services Client Access Licenses (TS CALs) are required if any of the integrated XenApp functionality is going to be used.

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