Architecture (ICA) is a Windows presentation services protocol from Citrix that
provides the foundation for turning any client device-thin or fat-into the
ultimate thin client. The ICA technology includes a server software component, a
network protocol component, and a client software component.
On the server, ICA has the unique ability to separate the application's logic
from the user interface at the server and transport it to the client over
standard network protocols-IPX, SPX, NetBEUI, TCP/IP and PPP-and over popular
network connections-asynchronous, dial-up, ISDN, Frame Relay and ATM. On the
client, users see and work with the application's interface, but 100% of the
application logic executes on the server.
The ICA protocol transports keystrokes, mouse clicks and screen updates over
standard protocols to the client, consuming less than 20 kilobits per second of
ICA is highly efficient-it allows only keystrokes, mouse clicks and screen
updates to travel the network. As a result, applications consume just a fraction
of the network bandwidth usually required. This efficiency enables the latest,
most powerful 32-bit applications to be accessed with exceptional performance
from existing PCs, Windows-based terminals, network computers, and a new
generation of business and personal information appliances.
With over two million ports in use worldwide, Citrix ICA is a mature, reliable
technology and is fast becoming a de facto industry standard for server-based
While all three
computing models have a valid role in today's enterprises, it's important to
note the differences between them. In the traditional client/server
architecture, processing is centered around local execution using fat, powerful
hardware components. In the network computing architecture as defined by Sun,
Oracle, Netscape, IBM and Apple, components are dynamically downloaded from the
network into the client device for execution by the client. But with the Citrix
server-based computing approach, users are able to access business-critical
applications-including the latest 32-bit Windows-based and Java™
applications-without requiring them to be downloaded to the client. This
approach also provides considerable total cost of application ownership savings
since these applications are centrally managed and can be accessed by users
without having to rewrite them.