Microsoft release for Windows NT 4.0 a product called Terminal Server Edition (TSE) and later embedded services in Windows 2000 called Terminal Services.  These products were developed by Citrix engineers.  In the agreement between Citrix and Microsoft, Citrix retained the rights to develop and market several other companion products.  Some people call these products “Citrix”, but they are made up of several individual products.  Citrix kept most of the goodies for its self.

• Citrix Presentation Server – Core functionality

• Citrix Installation Management Services (IMS) – Allows of the single installation of a product to multiple servers.  Also ensures a heterogeneous installation between servers.

• Citrix Resource Management Services (RMS) – Allows for the monitoring of multiple servers from one central database.  Also captures snapshots of what users were running what applications every 15 seconds.  All this with less that a 1% utilization of the processor.

• Citrix Load Balancing – A decision making browse to direct the user to the least busy server with the proper resource to service the users application request.  This gives the Citrix Server Cluster (or Farm) a level of fault tolerance.

• Citrix Web Server – Allows the user to launch there applications using an internet browse

Groundwork - Now that we have set the ground work, lets talk about why you should use Citrix products in addition to Microsoft Terminal Server Edition (TSE) or Microsoft Terminal Services.

• The Microsoft TSE or Terminal Services is based only on the RDP protocol.  When you use the Citrix products a more efficient protocol is made available called Independent Computing Architecture (ICA).  ICA has been shown to be 2 to 4 times faster than RDP.

• Using Citrix products you have the option to Cache Bit Maps that can be stored locally on the users computer.  Using this bit map caching the server can simply issue an instruction to redraw the required bit map at a specified location rather than constantly resending the same bit maps over and over again.

• Speed Screen 2 only sends information that changes.

• Seamless desktop integration of applications
   
• Ready Connect Clients – You can create a set of diskettes or a download directory and customize the setting to minimize the users need to configure the connection to your Citrix Servers.
   
• Load Balancing allows the users request to go to the least busy server with the proper resource to handle the request.

• Shortcuts to these applications may be pushed to the users desktop and later pulled back if the user does not have the privileges to execute the application.  The published application list can be managed from the server, which allows you to manage application for the users desktops without visiting the users desktop.
   
• Install an application on multiple servers from a single location.
   
• Deploy applications without rewriting application code.  Installation Management includes its own application installation monitoring utility that lets you replication any application installation without modifying the applications code.
   
• One-Stop application un-installation.
   
• Deploy application upgrade on multiple servers from a single location.
   
• Resource monitoring with less that a 1% utilization of the CPU on most servers.
   
• Single point of monitoring for multiple servers.
   
• Real time monitoring of over 30 essential metrics on servers, disks and network segments.  Visual cues (green, yellow and red) as well as audible cues are available.
   
• Built-in advice facility to recommend a solution to the issue as well as a technical discussion of the issue.
   
• Can create resource billing fees based on CPU usage, Memory usage, and session time.
   
• System History is available that gives detailed information about what was being executing every 15 seconds on a system for the past 12 hours as well as summary information for the past 2 weeks.
   
• Detailed analysis of both application behavior and user behavior.
   
• Heterogeneous computing environments. You can use the 286, 386 486, Pentiums, Windows based terminals, Network computers, Wireless devices, Apple Macintosh’s, Unix based computers, X-based devices, Internet Browser and some PDA’s to access Citrix Servers.  You can also use Windows for Workgroups, Windows 95, Windows 98, Windows ME, Windows NT workstation, Windows 2000, Windows CE, DOS, Unix, OS/2 Warp, Mac OS, and Java to access Citrix Servers.  You can use Standard telephone lines, T1, T3, 56kb, X.25, ISDN, PPTP, IPSEC, VPN, Frame relay, ATM, Wireless and Cellular Digital Packet Data, Internet, and Intranets to access Citrix Servers.  You can use TCP/IP, IPX, SPC, NetBios and Dial-in Async to access Citrix Servers.