For more than a decade now, Citrix and Microsoft have been intertwined in the world of remote access. The first release of Citrix WinFrame was in fact a rewritten NT3.51 kernel. Starting with NT4 Terminal Server Edition, Microsoft began licensing portions of Citrix’s technology and in return allowed Citrix to continue developing software for newer versions of Windows. Both companies have come a fair distance since then, with Citrix having had several major and numerous minor software releases, and Microsoft slowly altering and improving Terminal Services in their major OS releases. The latest example of this is the features list announced for Microsoft’s “Longhorn” version. Some rumors even had additional capability being provided by the R2 update for Windows 2003, but this seems to be just a rumor.
The quiet joke I have always heard when talking with Citrix personnel is that given enough time, Microsoft will finally have invented the same technology Citrix released in the late 90s. Certainly Terminal Services seems to have been something of an afterthought for Microsoft. They have never made a serious effort to challenge some of the areas that they clearly are weak in, and seem to be perfectly content with allowing Citrix to have the “extra 20%” space to play in. The reality is that the difference between the two products has been shrinking for some time now, and the “Longhorn” feature release will put serious pressure on Citrix to find new development channels. In fact, looking at the recent history of Citrix acquisitions and product steering it’s obvious they have reached that conclusion as well.
Citrix has always done very well in providing added benefits to users of Terminal Services. They have long filled gaps that made early editions of Terminal Services impractical for most deployment scenarios. They suffer from a fundamental weakness however: they are a third party add-on and that means more cash out of the budget. Citrix isn’t cheap, and they haven’t always been the greatest on delivering their value for Subscription Advantage customers. Their commitment over the last several years to have at least a service pack upgrade every year is commendable but many of us will probably remember that the promise was originally once every 6 months. And prior to XP FR2 or so, re-upping your SA for a year could quite literally be money down the drain.
Microsoft has an obvious edge here. You have to license Terminal Services before you can even begin to buy Citrix licenses, and that really starts to add up. For some organizations the cost really becomes prohibitive, and so more than one I.T. Manager is left asking “Why can’t I just use Terminal Services? Do I really need Citrix?” Well, it’s an interesting question. For some applications, some environments, and some budgets the answer becomes “Maybe not.” Let’s examine the areas where Citrix provides added benefits on top of Microsoft so that you can understand exactly what you will give up if you choose not to utilize Citrix with Windows 2003 Terminal Services.
The Application Experience
At the heart of it, Terminal Services still can’t publish an application. Citrix allows an administrator the choice to publish an application seamlessly to the user’s desktop, while Terminal Services only gives you a desktop session with the server. Those applications can be integrated into the client’s start menu and with Pass-Through authentication users might never realize they aren’t using an application local to their machine. The ICA client utilizes SpeedScreen technology to improve the responsive feel of applications provided through Citrix, and to better utilize available bandwidth you have control over the virtual channels bundled into the protocol. Citrix even provides some good tools to deal with “difficult” applications. The latest version, PS4, introduced the Application Isolation functionality to allow running multiple conflicting applications on the same server. They also extend support for client-side TWAIN devices, ActiveSync, and better local printer integration.
Terminal Services users will obviously be under significant limitations. Access to the application is through an RDP connection with the desktop session. Although the RDP protocol is on par with ICA in terms of general speed, it lacks some of the advanced controls that SpeedScreen and virtual channel control provides. And there are no additional tools provided to deal with multiple application versions or problem apps. That’s not to say it isn’t worth using. Many administrators who want to provide a remote desktop with several applications to their users find that Terminal Services functions just fine. The speed gap between RDP and ICA that used to exist has been reduced or eliminated, and printing support has been improved with Terminal Services so that if carefully managed, you can provide a reasonable print environment for your users. And I have to mention… it’s cheaper than Citrix.
The Management Experience
Another key area that Citrix excels in is management of the overall environment. With Terminal Services, three different tools are required to manage and configure the various pieces of the technology. Citrix incorporates the management of Presentation Server into a single tool, and even provides MMC snap-ins to integrate with Microsoft’s Management Console. Citrix allows published applications to be load-balanced across multiple servers with unique settings on each box, giving you reliability for critical business applications. Administrators can also configure Citrix policies to control user settings when they access Citrix applications, have comprehensive reporting with Resource Management Services, and integrate with other network management tools such as MOM and Unicenter.
Terminal Services does provide a management tool that can be used for multiple servers, but because there is no farm environment it lacks the universal settings that can be applied with Citrix. Without application publishing there is no real load balancing, although you can utilize server clustering in an Active-Active pair to give you some semblance of fault tolerance. There are no separate policies other than the traditional GPOs, and there is no reporting capability with Terminal Services. In the limited scenario mentioned above, the available management tools are adequate. And like I keep harping on… it’s cheaper than Citrix.
And all the Rest…
You have to consider everything that Citrix brings to the table with Presentation Server 4. You have the ability to use a web interface with SSL encrypted communications end to end. Conferencing Manager has now been included in their product without the need for additional licensing. The ICA client is supported on more client devices, and a Java client is provided when an actual client install is not needed or desired. Administrators gain some valuable optimization tools such as CPU Utilization and Memory Utilization management, giving you a granular level of control over some basic aspects of the user session. Terminal Services brings none of that… yet. “Longhorn” promises to bring seamless published applications, centralized management, a gateway service like Citrix provides, and a new RDP client version with improvements in speed and functionality. It continues Microsoft’s trend of chipping away at the core value of Citrix, and what I’ve said before will still hold true… it will still be cheaper than Citrix.
So if you simply look at the litany of reasons to choose Citrix it can get a bit daunting. You might even say “Why would I ever NOT want Citrix?” Hey, if you can afford it you might always want to have it. But if you are satisfied with the level of access you can provide now and are patient for “Longhorn” to bring all of the new improvements, it is possible that a good chunk of the list of weaknesses will simply dry up. I am sure Citrix will find new ways to improve the product and their value as an add-on. Just like I’m sure Microsoft will continue to incorporate many of those ideas into their next version of Terminal Services.