NFuse itself is actually comprised of three components, as shown in Figure 2.
NFuse component diagram
Citrix XML Service—The XML Service is configured to run on one or more of the MetaFrame servers in the farm and is responsible for brokering communications between the NFuse Java objects on the Web server and the Program Neighborhood service on the MetaFrame servers. Based on the authentication information received from the Java objects, the XML Service returns the appropriate application set information. If secure session tickets are used, then the XML Service must be installed on all servers in the farm that are publishing an application accessible through NFuse. I will talk further about session tickets in the article “Citrix NFuse 1.5 : Part 3 – Security.”
NFuse Java Objects—The Java objects are responsible for processing the user's authentication information by passing it to the Citrix XML Service. In return, they receive the appropriate application set data that is used to generate the HTML page. When the user clicks an application link on the page, these Java objects create the corresponding ICA file. This file contains all the information required for the user's ICA client to connect and launch the desired published application.
Citrix ICA Client/Web Browser—The user actually makes use of two separate applications. The first is the Web browser, which is used to display the appropriate NFuse Web pages. The other is the ICA client, which the browser relies on to process the ICA files associated with the application link on the Web page. I will look at the ICA client's role in an NFuse implementation in the article “Citrix NFuse 1.5:Part 2 The Role of the ICA Client.”