Two steps toward thinner clients

One of the hottest issues in networking is the emergence of cheap desktop machines running applications on powerful servers. This month, Citrix Systems, Inc. and Microsoft Corp. will ship complementary server-based products that, based on our tests, promise to add more fuel to that fire.

Microsoft, which knows a revenue opportunity when it sees one, has created a product to power the server side of the network computing equation in Windows NT 4.0 Terminal Server Edition (formerly code-named Hydra). Windows NT Terminal Server Edition (TSE) isn't an additional module to NT 4.0; it's more like an alternate version of the operating system, using system code licensed from Citrix. Applications run directly on the TSE server.

Citrix MetaFrame, formerly code-named pICAsso, is an add-on to TSE. MetaFrame provides support for Citrix's Intelligent Console Agent (ICA) protocol and offers features such as support for non-Windows clients. It can also balance the user load across a server farm, and monitor and remotely control user sessions.

We put Beta 2 versions of both products to the test to find out how functional they and the network computing model really are. We the products are appropriate for workgroups of users running multiple applications, as long as the applications are not graphical or compute-intensive in nature. We saw no noticeable delay when editing documents on a word processor or when working on a spreadsheet. TSE is right for groups of as many as 25 Windows users, but with MetaFrame's load-balancing addition, it can scale up to thousands of users on a variety of platforms.

Performance: moderate

While performance is crucial when you consider implementing one of these products, it's also one of the trickiest factors to quantify. There are no accurate standardized benchmarks to gauge factors such as client response time, network response and server load in multiuser installations. In fact, existing benchmarks give the wrong impression of these products because they test only the performance of the application running on the server, which would yield the same results as running the tests on a straight NT system. To test responsiveness, we had to resort to the old-fashioned approach - real people doing real work with actual applications.

We tested the two systems by timing keystrokes and commands typed at the client and measuring how quickly the server responded. We also watched the server with Windows NT Performance Monitor. Neither method is perfect; Performance Monitor is not an exact tool - the load it places on the server affects the results it reports. And for our small test network, the response time after typing at each client's keyboard varied an almost negligible amount - less than a second. It was like watching a movie in which the voices are ever so slightly out of sync with the motion of the characters' lips. Actively moving entire windows around the desktop, on the other hand, was more jerky.

We started with Microsoft Word, then brought up Microsoft Excel at the same time, first using the MetaFrame and TSE client software separately. We then mixed the two, with one client accessing the server through MetaFrame and another accessing the server through TSE. Finally, to toss a wrench in the works, we ran the Pinball game from the Microsoft Plus! Pack, an animated application that demands close to real-time responsiveness. While you probably wouldn't install Pinball on your multiuser system, it served as a stand-in for the kind of complex (and, unfortunately for us, far more expensive) CAD or graphics-intensive applications many organizations use.

Both products essentially work by transferring views of a session screen across the network. This approach means that applications such as Pinball, which display many moving graphics or require active user input, tend to be slow - really slow. With just one instance of Pinball running on one remote client, we were able to slow response time noticeably for all other sessions. Even without Pinball, some Web pages with active graphics displayed slowly, even when cached. On the positive end, common applications such as Microsoft Word, Excel and PowerPoint worked fine in a multiuser environment. Considering the size of these applications, it was surprising to see them working so smoothly.

Another surprise was the good performance we saw for remote users. Dial-up access to the server at 33.6K bit/sec worked just as well as the LAN systems, until we tried to run two or more active applications at a time. When we edited a document while downloading a Web page in two separate active windows, the cursor on the word processor would stop for several seconds while the client tried to catch up with the graphic updates on the browser.

Using MetaFrame's audio capabilities over a dial-up connection is not suggested. Poor remote system response gave us audio that was too choppy to understand. However, audio playback over a LAN sounded very good at CD-quality 44KHz.

There was practically no difference in performance between clients running applications on the server through TSE's and MetaFrame's respective protocols.

The client software for TSE and MetaFrame by default opens a window on the NT desktop that displays remote applications as subwindows. MetaFrame allows you to bypass this desktop view if you just want to launch a single application within what Citrix calls a seamless window. However, we found that this tactic made no difference in performance.

Administrative tools

While performance wasn't a distinguishing factor between the two products, the quality of their administration tools was. What we found lacking in TSE was made up for in MetaFrame. In fact, the tools with TSE are very similar to those available with Citrix's older WinFrame product, leading us to believe Microsoft really didn't put much effort into developing a single, cohesive administration tool. The tools have yet to be certified for the Microsoft Management Console.

Microsoft released TSE with a few separate administrative tools that should have been combined into one because they all perform different functions of multiuser administration.

Terminal Server Administration software lets you monitor current connections to the server and the processes it is running. You define the default behavior for the session through the Connection Configuration tool by setting the threshold for when an idle connection times out, defining what to do with broken connections, and determining whether users are allowed to log on automatically to a default account. This tool works for Microsoft's Remote Desktop Protocol and Citrix's ICA protocols. The License Manager and the Component Installer allow you to install user licenses and additional software included in the TSE package, such as Internet Information Server. Finally, NT's standard Performance Monitor tool has been enhanced to let you watch the status of user sessions and system variables associated with them.

MetaFrame's ability to "shadow" another user allows an administrator to view or remotely control a user's session. This is a valuable add-on that TSE does not yet have. It aids greatly in help desk applications and security monitoring.

If you install the load-balancing option for MetaFrame, there is an additional tool to set the parameters that determine the load per server within the farm. This allows a server to automatically reroute incoming logon requests to other servers.

This load balancing depends upon a number of factors - processor usage, memory usage, system pagefile usage, process and thread-swapping activity, and the ratio of total connections to free connections. You can set these criteria individually, or to make things simpler, Citrix gives you an Overall Adjustment slider bar that lets you set the overall calculated load of the server, an average of all the other parameters.

Installation

The installation process for TSE isn't too different from that of NT 4.0 - not surprising because it is NT 4.0 with system files modified for the multiuser features. Setup is simple. It took us about 30 minutes to install it.

MetaFrame's installation was equally quick. MetaFrame asks for the product license numbers and the transport protocols to support - TCP/IP, IPX or NetBEUI. Because you can't have the local client hard drives and the MetaFrame server drives mapped to the same drive letters, the product also asks you to specify how local client drives are to be remapped.

With both products, you should install application software through the Administrator account on the server because the applications' initialization files need to be mapped to a common system directory for all users.

Applications such as Microsoft Office were created for single users. To let you use Office under TSE, Microsoft gives you an application compatibility script you must call from the default startup command file for each user on your server. In the beta version we tested, only a handful of compatibility scripts are included. Without one, multiple users cannot see an application in their program groups and lack the proper environment variable settings.

By default, all users on the server are automatically configured for an application when you execute the application compatibility script. The default user profile executes a logon script that handles these compatibility issues. If you prefer that some users not have access to certain applications, you can create an alternative user profile for them that will run a different logon script.

After installing the server side, we turned to configuring clients for each product. For the TSE and the MetaFrame client, software installation is a no-brainer. The first time around, you have to install each on every client platform from the CD-ROM or through a client software installation diskette you can create with the administration tools. Once installed, both packages allow you to remotely update the client using administration tools.

We installed the 32-bit and 16-bit TSE and MetaFrame clients on our Windows 95 and Windows for Workgroups 3.11 client desktops, respectively. The installation of the software is fairly automatic. You need to configure specific sessions for each client to allow users to connect to servers or specific applications on servers. This can be a tedious process to do separately for each client, so it's best to preconfigure this information into the client software installation diskette. Once the software is installed, you have to configure a user session to the server using the Client Connection Manager. This involves specifying the server name, user information, window size, bandwidth information and the default application, if any, to launch upon logon.

Conclusion

Our bottom line: Don't expect either of these products to provide clients with the kind of performance and response time that an NT 4.0 system on their desktop would.

If you are a current WinFrame customer and are considering upgrading to TSE, you absolutely must have the MetaFrame add-on. It will save you a lot of time upgrading individual clients and will allow you to use non-Windows platforms as clients just as WinFrame does.

RELATED LINKS

Scorecard and NetResults
How we ranked the two in different categories, key findings and vendor info.

Protocols differ
A detailed look at the differences between the protocols used by the two systems.

Planning your TSE installation
What you need to consider first.

Citrix page

Microsoft's TSE overview

Shah has been writing on network topics since 1994. He is an independent consultant in Tucson, Ariz. He can be reached at rawn@rtd.com.