Reaching Beyond Windows

Windows NT Server 4.0 Terminal Server Edition is, in its basic form, limited to supporting client devices that are running some version of Microsoft Windows, whether it be Windows for Workgroups, Windows 95/98, Windows NT or Windows CE.

For connectivity from other platforms, we also looked at Citrix Systems Inc.'s new MetaFrame product. This $4,995 add-on, designed to work with Terminal Server, brings support for Citrix's Independent Computing Architecture (ICA) protocol, and with it support for several other client platforms, including DOS, Windows (16- and 32-bit), Macintosh, several flavors of Unix (HP-UX, Sun Solaris, IBM AIX and SGI IRIX), as well as some Web browsers and Java clients.

In our testing of MetaFrame's ability to extend Terminal Server functions to other platforms, we installed MetaFrame on two of our Terminal Server test servers. We then connected to it from a Sun Ultra 60 running Solaris 2.6. Neither the server nor the client portions of the product were at all difficult to install, with the server taking about 5 minutes and the client portion about 10.

The only obvious behavioral difference we found between the Citrix client on Solaris and the Microsoft client on NT had to do with multiple sessions. To access multiple sessions from the Sun platform, we needed to define a separate connection for each session. From the NT platforms using the Microsoft client, we used each defined connection to invoke as many sessions as was desired. Enabling round-robin access to the server required that we disable DNS caching on the Ultra 60 itself.

The ICA protocol used by Citrix also brings a number of other interesting capabilities to the MetaFrame product. Among the benefits is a concept called Application Publishing, through which an administrator defines the specifics of launching a particular application and thus makes that application immediately available from most systems.

MetaFrame also works in combination with Web servers to make published applications available through ICA-capable Web browsers such as Microsoft's Internet Explorer or Netscape's Navigator, with a free plug-in. These applications may be run directly or embedded into standard HTML Web pages, as desired.

On a more fundamental level, MetaFrame adds the capability for client sessions to access resources such as printers and serial ports either from the network or locally. Terminal Server does not yet provide this functionality, though it is planned for a future release. Finally, an add-in to the basic MetaFrame product is a tool for dynamic load balancing among multiple MetaFrame servers.