With XenApp 7.5, Citrix adopted the same architecture that was introduced in XenDesktop 5 and refined in XenDesktop 7, namely, FlexCast Management Architecture (FMA).
FMA is primarily made up of Delivery Controllers and agents. Delivery agents are installed on all virtual and/or physical machines that host and publish resources (named worker servers), while the controllers manage users, resources, configurations, and store them in a central SQL server database.
Unlike the previous versions of XenApp, the delivery agent now communicates only with the controllers in the Site and does not need to access the Site's database or license server directly, as illustrated in the following figure:
The main advantage of this architectural change is that now only one underlying infrastructure is used by XenApp and XenDesktop. Therefore, the overall solution might include both published applications and virtual desktops, leveraging the same infrastructure elements.
XenApp administrators who have moved to version 7.5 might be a bit confused; there are no more zones or data collectors. By the end of this chapter, you will find a table that maps concepts and terms from XenApp 6.x to the new ones in XenApp 7.5.