ICA is an architecture for server-based computing that competes with and/or complements other architectures such as Microsoft's Remote Desktop Protocol (RDP) and Sun Microsystems/X-Open's X-Window protocol. All of these architectures share in the goal to provide a means to extend resources, simplify application deployment and administration, and decrease the total cost of application ownership.
With all of these server-based computing architectures, applications are deployed, managed, supported, and executed completely on a server. Client devices, whether fat or thin, have access to business-critical applications on the server without application rewrites or downloads.
For everything that ICA, RDP, and the X-Window System have in common, they vary significantly from each other at the component level. Since very little new development is currently being done with the X-
As depicted in Figure 3-1, the ICA presentation services protocol transports only key-strokes, mouse-clicks, and screen updates to the client. The protocol has been demonstrated to
Figure 3-1: ICA presentation services
The ICA protocol was designed with low-bandwidth connections in mind, making it a robust performer on both large- and small-capacity links. Moreover, the ICA protocol responds dynamically to changing network, server, and client operating conditions. It takes advantage of available network and server resources and adapts automatically when conditions are more
Citrix MetaFrame enables us to deploy Windows applications to our students in both a very
cost-effectiveand expeditious manner. This is true whether they are working on a PC or Windows terminal on campus, or working offsite using an Internet connection.
Director of Computing Services,
Stanford Business School
SpeedScreen is a technology for improving the performance of application delivery across ICA links. It
Figure 3-2: How SpeedScreen improves link performance
With some applications, bandwidth consumption may be reduced by as much as 30 percent through the implementation of SpeedScreen, while total packets transmitted may be reduced by 60 percent. The result is lower latency in the network and better application performance for the end user—
With the SpeedScreen Latency Reduction (SLR) manager, the end-user experience can be enhanced in two ways. First, local text echo can be enabled to give immediate feedback by having the local client render the text. The normal way text is transferred when using MetaFrame is by sending the keystroke to the server, which is
A broader range of connectivity options are supported by MetaFrame and ICA than by RDP, so a more diversified set of users can access and utilize hosted applications. Figure 3-3 depicts the connectivity options enabled by ICA, which include dial-up, ISDN, multiple LANs, wireless LANs,
Figure 3-3: ICA's connectivity options
Additionally, using MetaFrame and the ICA protocol breaks the barriers imposed by RDP by extending application access beyond Windows PCs. The ICA protocol supports more than 200
In addition to the contributions of MetaFrame and the ICA protocol to application delivery performance, MetaFrame also enhances the basic multiuser client-server environment. MetaFrame XP embodies numerous innovations designed to facilitate a broad range of hosted application environments. Considerable effort has been invested by MetaFrame XP designers to enable all applications, whether remote or local, to operate and
The MetaFrame ICA desktop is designed to provide a user experience that is on par with a Windows PC running locally installed and executed applications. MetaFrame enables complete access to local system resources, such as full 16-bit stereo audio, local
The mapping of local resources can be performed automatically or by means of administrative utilities. Specialized client capabilities such as modem dial-up are also supported.
Additionally, mapped resources can be shared with the MetaFrame server, if desired. Configuration of these mappings is built into the standard Windows device redirection facilities. The client mappings appear as another network that
Of course, not all MetaFrame XP
Seamless Windows is a shorthand expression referring to the capability of the Citrix ICA Win32 client to support the integration of local and remote applications on the local Windows 95, Windows 98, Windows NT 4.0, Windows 2000, or Windows XP desktop. When configuring a connection to the MetaFrame XP server, an administrator or user can simply select the Seamless Windows option to enable this function.
With Seamless Windows, the user can gain access to hosted applications without having to load a remote desktop environment. While connected in a MetaFrame XP server session, the user can gain access to local applications using the Windows taskbar. Icons for both local and remote applications can be installed on the local Windows desktop, and both local and remote application windows can be cascaded on the local desktop.
The Seamless Windows environment supports the definition of multiple keyboards to facilitate command entry in local and remote application environments. This
Windows Clipboard Seamless Windows supports the use of the Windows Clipboard in conjunction with both local and MetaFrame-hosted applications. Users can cut, copy, and paste information between applications running remotely on the server or locally from the desktop. Rich text format cut-and-paste is fully supported.
The local/remote clipboard is part of MetaFrame XP's overall solution set. It can be used independently of Seamless Windows or Program Neighborhood.
Building on the concept of a Seamless Windows environment, MetaFrame also delivers an easy-to-use method for accessing remotely hosted applications. Similar in concept to the Microsoft Windows Network Neighborhood, MetaFrame pushes links to published applications into a client-based Program Neighborhood facility.
In operation, Program Neighborhood presents application sets to MetaFrame client users. An
is a user's view of the applications published on a given MetaFrame server or server farm, which that user is authorized to access. A single user- authentication operation (usually initiated when the user launches Program Neighborhood or a MetaFrame-hosted application displayed in the Start menu or as an icon on the local desktop) identifies the user to all MetaFrame servers. Based on the user's individual or
Program Neighborhood technology is especially useful as a means to quickly publish hosted applications that are intended for use by groups of users. Users can click the Program Neighborhood icon on their Windows desktop (or click the corresponding entry in their Windows Start menu) to review a list of hosted applications available for use. No special client configuration is required to launch and use these published applications.