Citrix Gives AS/400 Stamp of Approval

Citrix Systems Inc. gave IBM's AS/400 its stamp of approval last month when the Fort Lauderdale, Fla.-based software company announced its MetaFrame server-based computing software now supports the AS/400 Integrated Netfinity Server.

Using the Integrated Netfinity Server, AS/400 network administrators can now install and run Citrix MetaFrame and Microsoft Windows NT Server 4.0, Terminal Server Edition in their AS/400 environments. In January of this year, Citrix granted IBM the right to embed Citrix's Independent Computing Architecture (ICA) into IBM products, essentially opening the door for IBM to incorporate this thin-client/server protocol into the AS/400's framework.

This latest Citrix announcement indicates the company has turned its attention toward the AS/400 and its Integrated Netfinity Server technology, formerly known as the Integrated PC Server (IPCS), according to Stephen Malkinson, Citrix alliance executive with IBM's Network Computer Division. "Citrix does not go out and test its products on just any system or software. They're very selective in what they do."

Even though Citrix does not have a formal certification program, the company is essentially saying it has taken the time to bring in an AS/400, set it up, learn how it works, test it and document these tests, Malkinson points out. "[Citrix] wanted to satisfy for themselves that this is really a good solution," he says.

The benefits of using MetaFrame on the Integrated Netfinity Server are expected to be numerous. In addition to promoting server consolidation and single-point systems management, Citrix MetaFrame contained within the AS/400 appeals to the AS/400 user's notion of network-centric computing, according to David Manks, senior product manager with Citrix.

"The AS/400 community is very familiar with the computing model created by Citrix and its products," Manks says. "This can be attributed largely to the AS/400 market's familiarity with server-based, network-centric computing, where all the execution takes place on a server and users have a thin client -- or a fixed function device -- on the client side that gains access to the information."

The AS/400 environment is one that has been committed architecturally and culturally to a two-tier system [terminal and central processor], agrees John Girard, a research director and VP in Gartner Group's Network Center (Stamford, Conn.). "AS/400 users may want access to additional packaged applications and new clients, but they don't want to go into a three-tier client/server world," he says. "The Integrated Netfinity Server appeals to these people by making the network configuration appear two-tier."

While there is essentially no difference in performance or logic between an integrated and a separately networked Netfinity server, to the AS/400 network administrator it is more natural to put the additional Netfinity processor inside the AS/400, according to Girard. "This is a way of supplying a Citrix server that architecturally and culturally is a fit with the traditional AS/400 shop."

Using MetaFrame, AS/400 users have access to full client enterprise applications while their network administrators use the Citrix ICA protocol to maintain a two-tier architecture. "The desktop is still just a terminal as far as its relationship with the AS/400," Girard says.

The ICA protocol is made up of three components: a server component that does much of the rendering out to the client; a presentation protocol that works on top of any transport protocol; and a client side program that establishes a connection to the server.

As of June 1998, the Network Station Manager was given the capability to download Citrix's ICA client side program from wherever the Network Station boots, according to IBM's Malkinson. "The ICA client code has been ported to a wide degree of platforms [including Macintosh, Unix, Java, etc.]," he says. "Think of an ICA client as nothing more than a Windows emulator. It does the same things as a 5250 emulator, except it provides for the remote presentation of Windows."

In the Network Station scenario, the client sits on the Network Station and allows the user to gain access to the server, Manks explains. MetaFrame runs on the Integrated Netfinity Server on top of Microsoft Windows NT 4.0 Terminal Server Edition. The user's client runs the ICA client program to enable the connection.

"[Windows NT Terminal Server Edition] does everything the standard NT server does, it just has the multi-user capability," Malkinson says. "A number of users can access Word, for example, at the same time. The NT server sees all of its clients as terminals (regardless of whether they are PCs or thin clients). Citrix MetaFrame provides a value-added software layer on top of Terminal Server Edition that provides the ICA client."

MetaFrame works in conjunction with Terminal Server Edition, extending the terminal server experience in three key areas, Manks points out. First, MetaFrame provides additional enterprise management capabilities to the terminal server, including features such as: load balancing, application publishing, program neighborhood and session shadowing.

Second, Citrix technology extends terminal server by providing heterogeneous capabilities, accommodating Windows clients as well as non-Windows clients, according to Manks. "Our ICA protocol enables the communication between server and client and is optimized for low-bandwidth to high-bandwidth connection," he says.

The third way Citrix extends terminal server is through desktop integration. "This provides the users with the look and feel of server-based computing, as if they're running locally," Marks explains. "Our approach is that the user doesn't know, nor should they have to know, where the application is executing. This is accomplished, in part, through local print support, local drive mapping, local comp support, the ability to drag icons from the Citrix client to the start menu or the desktop."

The MetaFrame product is particularly valuable to large enterprises with heterogeneous desktops, Malkinson points out. "The Citrix ICA is like a universal language," he says.

Gartner's Girard hesitates to categorize the MetaFrame-Integrated Netfinity Server relationship as a universal answer. "If you're an enterprise that really is trying to do a full thin-client rollout for lots of different purposes -- giving users access to different file servers, applications on multiple platforms and the AS/400 server -- maybe this doesn't make sense," he says. "Maybe you want to buy a separate Windows NT box or a cluster of servers and use the cluster management feature within MetaFrame. If really what you wanted to do is general terminal emulation, then I would recommend a Web interface.

Still, Girard continues, "this is a great solution to give you more flexible access using fat clients into that AS/400 world, but still having look and feel and taste like a legacy two-tier access mechanism for a traditional AS/400 user."