The Evolution of MetaFrame

The Microsoft Windows NT operating system developed from a single-user operating system architecture and continued, for nearly a decade, only to be limited in certain applications by that fact. Windows NT provided real-time multiprocessing capabilities comparable to those of rival UNIX operating systems, but did not provide functions within its OS kernel to support concurrent multiuser access to applications hosted on NT platforms.

Given the dominant business computing architecture of the late 1980s and early 1990s, which featured increasingly capable desktop computers (so-called fat-client PCs) that provided much of the same processing as client-server applications, it may well be that the need for multiuser computing platforms (similar in concept to mainframe computing environments) was not of primary concern to Microsoft designers. In Microsoft's preferred computing model, information processing was conceived as inherently distributed and individualized: desktop computers were viewed as "peers" of server platforms. In fact, most early server systems were little more than highly configured PCs, typically featuring many of the same hardware components.

At that time, there was an interest in some niche areas for a server platform that would "host" applications and share them among several connected client devices, configured as dumb terminals. One such application was remote access: a technique by which one or more offsite users could access an application located on a corporate local area network (LAN). Ideally, the remote user would be able to perform useful work as though seated at a terminal directly attached to the LAN.

However, the mainstream architecture for business computing did not yet involve shared application use. Instead, the norm was a combination of Windows-based desktop computers, emphasizing locally stored and executed individual applications, and Novell, UNIX, or NT-based servers (or a combination of all of these) interconnected via a LAN, supporting client-server computing.

Multiuser Windows—MultiWin

The idea behind server-based computing on Windows NT can be traced to the X-Window System developed by MIT in 1984. By utilizing powerful UNIX servers, remote X-Window clients can send keyboard and mouse input to server-based applications running on central servers. The X-Window System on the server then tracks output from the applications and updates the appropriate remote client session screen.

The founder of Citrix Systems, Ed Iacobucci, originally conceived the idea of allowing different types of computers to run the same applications, even though they might not have the same operating system or adequate local resources. While working as head of the joint Microsoft/IBM design team on the OS/2 project, he approached both companies with the idea, but neither firm was interested. Iacobucci then formed Citrix Systems in 1989 and the technology behind the current Terminal Services was developed—MultiWin. MultiWin rode on top of the OS/2 kernel and allowed multiple simultaneous OS/2 sessions and desktops in a protected memory area for each individual user.

WinView

In 1993, Citrix shipped its first OS/2-based multiuser operating system, called WinView. WinView used the MultiWin technology and one of the first incarnations of a remote display client called Independent Computing Architecture (ICA). Citrix first worked to deliver multiuser extensions to the OS/2 operating system and subsequently worked on the delivery of applications across Novell and TCP/IP networks. Despite prevailing personal and client-server computing models, developers at Citrix believed that multiuser computing had a future, especially as applications moved off the desktop and "into the network." They convinced Microsoft that a market for multiuser NT could be cultivated and secured a license to add multiuser extensions to the NT operating system.

WinFrame

Whether or not Microsoft shared the Citrix vision of the future, the license agreement was certainly a "win-win" for Microsoft and Citrix. With the multiuser extensions provided by Citrix in the form of WinFrame, Microsoft would be able to answer criticisms from UNIX advocates regarding a purported "deficiency" of its server operating systems: they provided little or no support for multiuser computing requirements. If Citrix visionaries were correct, and a market for multiuser computing platforms could be cultivated, Microsoft would have a solution to offer that market.

Citrix WinFrame is a combination of Microsoft Windows NT 3.51 Server and Citrix MultiWin technology. WinFrame was a major upgrade to the OS/2-based WinView. At the time of its release, Windows 3.1 (and later, Windows 95) had become the desktop standard, and WinFrame surpassed WinView as a tool for installing and executing the standard corporate end-user applications.

Thin-Client Computing

In the mid-1990s, the argument for multiuser NT was reinforced by the findings of analysts such as the Gartner Group regarding the total cost of ownership of Windows PCs. Analysts claimed that fat-client PCs cost organizations between $7000 and $13,000 per PC per year in maintenance and support. This position touched off a firestorm of industry activity, mainly from longtime Microsoft rivals. The so-called SONIA set—an acronym for Sun Microsystems, Oracle Corporation, Netscape Communications, IBM, and Apple Corporation—led the charge to displace Microsoft PCs from corporate desktops, substituting their own "network computer" in their place. Despite the obvious self-interest inherent in the SONIA value proposition, and the subsequent failure of the network computer to take hold in the market, the underlying tenant of the SONIA argument took root. The Citrix concept of thin-client computing was introduced to the lexicon of modern business computing.

Thin-client computing advocates held that, as server capabilities grew, it was only natural for server hosts to become "fatter" and for desktop platforms to become "thinner." Application software, advocates argued, should reside on application servers rather than on individual PCs. Placing applications on a server would make them accessible by means of a variety of inexpensive client devices. The advent of the Internet and World Wide Web at about the same time reinforced this perspective. Many people adopted a view of computing in which all applications would be accessed via a universal, hardware-agnostic client such as a web browser.

Citrix Systems Synonymous with Thin

Citrix Systems, with its Independent Computing Architecture (ICA), emerged from the discussion of thin computing as the undisputed leader in a market it had long helped to facilitate. In an ICA-based solution, WinFrame-based application servers could host Windows-compliant applications, while end users, equipped with any of a broad range of client devices (whether network computers or Windows PCs), could access and use the applications over a network connection. Integral to the WinFrame approach was a remote presentation services protocol capable of separating the application's logic from its user interface, so that only keystrokes, mouse-clicks, and screen updates would travel the network. With the ICA protocol, Citrix claimed, the user's experience of the server-hosted application would be comparable in all respects to that of an application executing on the end user's own desktop PC.

Terminal Services and MetaFrame

Increased interest in the WinFrame solution encouraged Microsoft to license MultiWin, the core technology of WinFrame, from Citrix Systems in 1997 and to integrate the technology into its own operating systems soon after. As explained in Chapter 2, Microsoft first implemented MultiWin in a special Terminal Services Edition (TSE) of its NT 4.0 OS. With Microsoft's integration of Terminal Services, Citrix needed to raise the bar for scalability and management. This was accomplished with MetaFrame.

Introduction of MetaFrame 1.0/1.8

Unlike WinFrame, which had been a stand-alone product and a "replacement" operating system for NT, MetaFrame was an add-on to the Microsoft NT 4.0 TSE and Windows 2000 platform. One reason for the MetaFrame product was to continue to meet the needs of WinFrame customers who were interested in migrating their NT 3.51-based WinFrame environments to newer NT 4.0 TSE-based environments but who were afraid of losing application server connections with clients that were not supported by Remote Desktop Protocol (RDP). MetaFrame added ICA client and protocol support back into the Microsoft multiuser operating system offering, since ICA allowed for connectivity from many additional clients than RDP allowed.

MetaFrame XP

MetaFrame XP is the latest version from Citrix. With the release of Feature Release 3 (FR-3), XP is compatible with Microsoft's latest operating system: Windows Server 2003. In addition to the feature updates and changes, another very significant change that Citrix made with MetaFrame XP is the change in licensing; MetaFrame 1.0/1.8 Citrix required a server license for every server with Citrix installed as well as bump packs for additional users, while MetaFrame XP only requires one base license for each server farm (with bump packs for additional concurrent users). This change makes licensing far more flexible and convenient, and in most cases cheaper, as additional servers can be brought online as needed without additional Citrix software license expense (as long as no additional concurrent users are added).

With MetaFrame XP, customers have new version choices, including XPs, XPa, and XPe. All versions of XP are supported on Windows NT 4.0 TSE, Windows 2000 Server, and Windows Server 2003. MetaFrame XP supports full integration with Active Directory in Windows 2000 or Windows Server 2003.

Note

Following the release of Feature Release 1, Citrix stopped adding any additional features or enhancements to MetaFrame XP for Windows NT 4.0 TSE.

XPs is the standard version for Citrix servers for stand-alone point solution implementations with one to five servers. XPs feature highlights include MetaFrame Web Interface for MetaFrame, user shadowing, Secure Gateway, Universal Print Driver II, client time zone support, Novell NDS support, client device support, and full ICA client support.

Although more than one server can be used with XPs, it is rare, as applications cannot be load balanced across servers and any application publishing will have to be done separately on each server with different names.

XPa is the advanced version that includes all of the XPs features, with the addition of Load Management. This upgrade is designed for use in farms with 2 to 100 servers.

As shown in Table 3-2, XPe contains all the features included with XPa, as well as some additional features required for enterprise management. These extended features include Resource Manager, Installation Manager, Web Interface Extension for MetaFrame XP (formerly Enterprise Services for NFuse), a plug-in for Microsoft Operations Manager (MOM), and Network Manager. XPe is designed for 20 or more servers and accommodates multiple Citrix Server farms.

Table 3-2: MetaFrame XP FR-3 Feature Grid

	MetaFrame XPs	MetaFrame XPa	MetaFrame XPe
UNPARALLELED MANAGEABILITY AND SCALE
Advanced Shadowing
Cross-server shadowing	X	X	X
Many-to-one shadowing	X	X	X
One-to-many shadowing	X	X	X
Shadowing indicator	X	X	X
Shadowing taskbar	X	X	X
Application Management
Anonymous user support	X	X	X
Application publishing	X	X	X
Content publishing	X	X	X
Program Neighborhood	X	X	X
TCP-based browsing	X	X	X
Application Packaging and Delivery
Centrally install and uninstall applications			X
Create logical server groups			X
Customizable project details			X
Delivery verification			X
Distribute service packs, updates, and files			X
MSI support			X
Package applications, files, and service packs			X
Package inventory			X
Packager rollback			X
Schedule package delivery			X
Server reboot support			X
Support for unattended installs			X
Centralized Administration
Active Directory support	X	X	X
Novell NDS support	X	X	X
User policies	X	X	X
Administrator toolbar	X	X	X
Centralized Data Store	X	X	X
Citrix administrative accounts	X	X	X
Citrix Management Console	X	X	X
Plug-in for Microsoft Operations Manager (MOM)	X	X	X
Citrix Web Console	X	X	X
Connection control	X	X	X
CPU prioritization	X	X	X
Windows Installer Support	X	X	X
Centralized License Management
Centralized license activation	X	X	X
Enterprisewide license pooling	X	X	X
Plug-and-play licensing	X	X	X
Client Management
Auto client update	X	X	X
Business Recovery	X	X	X
ReadyConnect	X	X	X
Web-based client installation	X	X	X
Network Management
Access CMC from third-party management consoles			X
SNMP monitoring agent			X
Printer Management
MetaFrame Universal Print Driver version II	X	X	X
Support for color and high-resolution printers with Universal Print Driver	X	X	X
Printer auto creation log	X	X	X
Printer driver access control	X	X	X
Printer driver replication	X	X	X
Printing bandwidth control	X	X	X
Resource-Based Load Balancing
Instant load-balancing feedback		X	X
Load balancing reconnect support		X	X
Schedule application availability		X	X
Specify client IP range		X	X
Scalability
Enterprise-class scalability	X	X	X
Cross-subnet administration	X	X	X
System Monitoring and Analysis
Application monitoring			X
Customized reporting			X
Summary database and reporting			X
Perform system capacity planning			X
Real-time graphing and alerting			X
Server farm monitoring			X
Track user access to applications			X
User-definable metrics			X
Watcher window			X
ICA session monitoring			X
TOTAL" NET" LEVERAGE
Web Application Access
Web Interface for MetaFrame	X	X	X
Federal Information Processing Standards (FIPS) 140 security compliance	X	X	X
Support for RSA Secure ID and Secure Computing Premier Access second factor authentication solutions	X	X	X
Multiple server farm support	X	X	X
Application filtering and caching	X	X	X
Support for MetaFrame Secure Access Manager	X	X	X
Web Interface Extension for MetaFrame XP			X
ULTIMATE FLEXIBILITY
Access to Local System Resources
Auto printer creation	X	X	X
Automatic drive redirection	X	X	X
Client drive mapping	X	X	X
Clipboard redirection	X	X	X
COM port redirection	X	X	X
Performance
Instant mouse-click feedback	X	X	X
Persistent bitmap caching	X	X	X
Priority packet tagging	X	X	X
SpeedScreen browser acceleration	X	X	X
SpeedScreen 3	X	X	X
Text-entry prediction	X	X	X
Seamless User Experience
High-/true-color depth and resolution	X	X	X
16-bit audio support	X	X	X
Application save position	X	X	X
Auto client reconnect	X	X	X
Client printer management utility	X	X	X
Client time zone support	X	X	X
Content redirection	X	X	X
Multimonitor support	X	X	X
Panning and scaling	X	X	X
Pass-through authentication	X	X	X
Roaming user reconnect	X	X	X
Seamless windows	X	X	X
Win 16 multi-session support	X	X	X
Universal Connectivity
Universal client access	X	X	X
Support for direct asynch dial-up	X	X	X
Support for TCP/IP, IPX, SPX, and NetBIOS	X	X	X
User Collaboration
User collaboration	X	X	X
END-TO-END SECURITY
Security
MetaFrame Secure Gateway	X	X	X
Delegated administration	X	X	X
SSL 128-bit encryption	X	X	X
TLS encryption	X	X	X
Smart card support	X	X	X
SecureICA 128-bit encryption	X	X	X
SOCKS 4 and 5 Support	X	X	X
Ticketing	X	X	X

The centralized computing using MetaFrame XP provides us with the ability to completely customize which applications are provided to which users. This ensures that all users have access to the necessary resources required for their daily tasks. Software changes and upgrades are performed at the server effective instantaneously for all users. Overall, we have been able to expand and grow our IT projects ahead of estimated schedules with the seamless deployment of applications and minimum maintenance time required for our Citrix Farm.

—Michael P. Miller
Network & Systems Administrator
Primary Care Partners, P.C.

MetaFrame XP is Active Directory compliant. Thus, Active Directory groups may be used to configure permissions and users. Citrix does not change or add to the schema of Active Directory, and MetaFrame allows single sign-on for Active Directory, Novell NDS, and Novell e-Directory environments.

Web interface for MetaFrame is provided by Citrix, with all three MetaFrame XP versions to publish Windows applications to web pages on intranets and the public Internet. This tool also allows customization so that a number of applications can be combined into an "application portal." Additionally, MetaFrame Secure Gateway provides a secure method of application access delivered directly to the end user via a browser, over SSL, providing increased security while reducing problems with Firewall and VPN configurations.

With MetaFrame XP, access to applications can be provided across a variety of networks, including wide area networks, remote access dial-up connections, local area networks, the Internet, and wireless networks. Over 200 types of clients, including Windows PCs, Windows terminals, UNIX workstations, handheld devices, network computers, and numerous others, are supported as ICA clients. These client choices improve dramatically on the RDP client support inherent in Windows NT 4.0 TSE, Windows 2000 Server, and Windows Server 2003.