Citrix XenApp

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Citrix XenApp
Developed by Citrix Systems
Latest release 4.5 / February 11, 2008 (2008-02-11); 123 days ago[1]
OS Microsoft Windows Server
Supported by v4.0
HP-UX - Solaris - AIX
Genre Application Virtualization
License Proprietary
Website www.citrix.com

Citrix XenApp (formerly Citrix MetaFrame Server and Citrix Presentation Server) is a remote access/application publishing product that allows people to connect to applications available from central servers. One advantage of publishing applications using XenApp is that it lets people connect to these applications remotely, from their homes, airport Internet kiosks, smart phones, and other devices outside of their corporate networks. From an end-user perspective, users can log in to their corporate network from, for example, an airport kiosk, see all of the applications they would see everyday at work, including Outlook email and any internal applications, and access them from the kiosk in a secure environment. To the user, the application would appear as if it was installed and running on their computer (seamless desktop integration), whereas in reality, the application is running on XenApp, usually hosted in their corporate environment.

Networks that use this software are reminiscent of the mainframe-terminal system, where a central powerful computer does most of the processing work and smaller, much less powerful machines provide the user interface.

Some academic institutions use XenApp to provide their students and faculty with remote access to applications running on campus servers.

Contents

[edit] Technical details and licensing

XenApp is built on the Independent Computing Architecture (ICA), Citrix Systems' thin client protocol. The Microsoft Remote Desktop Protocol, part of Microsoft's Terminal Services, is based on Citrix technology and was licensed from Citrix in 1997. [2] Unlike traditional framebuffered protocols like VNC, ICA transmits high-level window display information, much like the X11 protocol, as opposed to purely graphical information. This is possible because the Citrix Display Driver which is installed in Session Space is capable of capturing high level GDI draw commands, which can be replayed on GDI-capable clients, for example Windows-based clients. Clients are available for several operating systems, including Microsoft Windows (CE, 16-bit, 32-bit and 64-bit platforms), Mac OS, Linux, and other Unix-like systems.

Citrix MetaFrame version 3.x and 4.x servers listen for client connections on TCP port 2598, by default. [3] [4] If the Session Reliability feature is disabled, then the server will listen on port 1494. Older MetaFrame servers (those running MetaFrame version 2.x or earlier) do not have the Session Reliability feature, and therefore always default to port 1494.

The Citrix Developer Network contains a set of software development kits that enable custom development for XenApp. These SDKs include the following:

  • Citrix XenApp SDK
  • Citrix Virtual Channel SDK
  • Citrix ICA Client Object SDK
  • Citrix Web Interface SDK
  • Citrix Simulation API SDK

XenApp resides on a Microsoft Windows computer, which can be either standalone or part of a larger cluster of Citrix servers. It is important to note that in addition to per-user Citrix licensing, there must exist a Terminal Server Client Access License (CAL) and a Windows Server CAL from Microsoft for each client connection. Both products must be adequately licensed for the environment to function correctly.

There is a web-based Citrix client, freely available under the name Web Interface for XenApp. The Web Interface may be used as a secure ICA proxy over HTTPS when combined with Citrix Secure Gateway, both of which are included in the base XenApp product. XenApp also supports three UNIX variants: HP-UX, Solaris, and AIX.

[edit] UNIX version

Presentation Server for UNIX is available for Solaris (SPARC and x86), AIX, and HP-UX. Patches typically come out first for the Solaris version. The product started as MetaFrame for Solaris 1.0 which was released in March of 2000.[5] MetaFrame for UNIX (MFU) 1.1 added support for AIX and HP-UX and came out in the fall of that year and Feature Release 1 came out about a year later. The next version came out in the first half of 2003. It was originally planned as MFU 1.1 Feature Release 2 but was rebranded MetaFrame Presentation Server for UNIX 1.2.[6] However, references to MFU 1.1. FR2 can still be found (e.g. in the license key). Presentation Server for UNIX (PSU) 4.0 was released in the first half of 2005 and was the first version to be bundled with the Presentation Server suite.[7] Existing customers paying for upgrades and new versions (known as Subscription Advantage) can however continue to get just the UNIX version. Existing MFU 1.x installs cannot be upgraded to PSU4; instead a clean install is required.

[edit] Competition

Traditionally Citrix Presentation Server has faced minimal or no competition in the thin client computing space. But with Microsoft's new Terminal Services for Windows Server 2008, Microsoft Terminal Services is emerging as a clear competitor to XenApp at least in the small and medium business market space. Another XenApp competitor is Ericom Software, PowerTerm WebConnect. XenApp is built on top of the Windows Terminal Services platform which was originally developed by Citrix in the early-mid 90s.

[edit] See also

[edit] References

  1. ^ (2007-02-12). Introducing Citrix XenApp. Citrix Systems. Retrieved on 2008-04-12.
  2. ^ Microsoft and Citrix Sign Technology Cross-Licensing and Development Agreement: Microsoft Signs Agreements With Citrix and Prologue Software
  3. ^ CTX104147 - Explaining ICA Session Reliability, Common Gateway Protocol, on TCP Port 2598 - Citrix Knowledge Center
  4. ^ Goodbye 1494, Hello 2598! Citrix Enhances ICA and Changes its Default Port - From BrianMadden.com
  5. ^ C. Thi Nguyen (March 22, 2000). MetaFrame for UNIX Rises with Sun Solaris. WindowsITPro.com. Retrieved on 2007-05-22.
  6. ^ MetaFrame(R) Presentation Server for UNIX(R) 1.1 and 1.2. Citrix. Retrieved on 2007-05-22.
  7. ^ Chris Gilbert (Apr 27, 2005). Presentation Server for Unix 4.0 details. Citrix. Retrieved on 2007-05-22.

[edit] External links

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Remote administration software