http://www.microsoft.com/TechNet/analpln/cs/sqnt779t.htm (PC Press Internet CD, 03/1996)
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Solution Goal: Full Integration, Minimal Disruption
Sequent's decision to launch a line of Windows NT-based symmetric multiprocessing (SMP) servers in late 1992 brought with it the goal of integrating Windows into the daily business operations of the company. Sequent has a long-standing commitment to run its business using the products it markets.Until 1993, Sequent ran its business using several of its own multiprocessor UNIX host systems that provided manufacturing, sales, and financial systems to the company's worldwide workforce of more than 1,600 employees. Some regional sales offices and departments at the corporate headquarters had scattered stand-alone PCs, Macintosh® machines, and a few local area networks running a UNIX-compatible version of Novell® Net-Ware®. However, there were no standards for these non-UNIX systems and no concerted effort to integrate them into the primary business systems of the company.
The commitment to adopt the Windows platform into the core of Sequent's operations represented a significant new direction for the company and its employees, both technologically and culturally. Consequently, there were several "musts" that defined this effort. The new platform must integrate with the existing UNIX-based file, print, and e-mail services, be easily scalable in size as Sequent's business grows, be flexible in order to respond to changing business needs, and allow users to automate themselves according to their individual workgroup needs. In addition, users should be able to work from their office, at home, or on the road, with all system features available to them regardless of their location.
According to Matt Miller, the technical leader for this effort at Sequent, the company was looking to the Windows-based solution to provide Sequent with the choice of a wide range of personal productivity applications, such as spreadsheets and word processors. Moreover, Sequent hoped to gain operational advantages by adopting Windows-based workgroup line-of-business applications-for order processing, sales contact management, and more-that were not previously available on the UNIX platform.
While the new Windows-based platform would give the company the freedom to choose from a broad range of such applications, it was imperative that the move minimize changes to the company's existing UNIX infrastructure. There were two reasons for this: to keep the cost of adopting a Windows platform as low as possible and to avoid interruptions to daily business operations.
Solution Architecture
The solution that Sequent devised waxs a standard package of Windows-based software and hardware that can be easily integrated into the existing UNIX infrastructure. This package or "subnetwork" can be duplicated at any Sequent site and scaled to the number of users, from several workstations to hundreds. The integrated solution Sequent developed is a "cookie cutter" model that allows for a gradual roll-out of Windows technology into different parts of the company. Sequent's subnetwork model is centered around one of Sequent's own multiprocessor WinServer systems running the Windows NT™ Advanced Server operating system and linked to single-processor 486-based PCs running Windows for Workgroups.
The services provided to end users by the standard subnetwork configuration include terminal access to the existing UNIX character-based applications; access to Sequent® Symmetry® machines running Novell NetWare for UNIX (for links to Sequent's existing Novell file and print servers); access to Sequent Symmetry machines running Syntax's LM Server (for links to Sequent's existing UNIX-based printer network); access to SQL Server for Windows NT running on the multiprocessor WinServer machine for file and database services; a mail gateway to interconnect Microsoft Mail with Sequent's existing SMTP mail network; a network-attached fax server; a color scanner; and a CD-ROM server. In addition, a dial-in modem server in the subnetwork package allows remote PCs, either home-based or portable, to access all of these services as if they were connected directly to the subnetwork in a particular Sequent office. In addition to the Microsoft Mail and Schedule+ applications included with Windows for Workgroups, each user is also provided with the Microsoft Office family of programs for Windows.
This entire package of Windows-based services can be tied into the company's worldwide ethernet and frame relay network at any Sequent location.
"We selected the four people from IS and relocated them
to a temporary location ...and put them into this new environment
with developers for Windows NT around them ....
They became part of the team here."
Matt Miller, Technical Lead,
Sequent Computer Systems
Development Personnel
Sequent used an in-house staff of six to create and launch the initial Windows NT subnetwork model for the company. This team included two people-Miller and one other developer-from the company's new Windows NT Business Unit. Joining Miller and his associate were four people from Sequent's own UNIX-centered Information Services department.
Miller explains the valuable mix of skills that comprised the project team: "One of the four was Sequent's primary UNIX network architect who designed our worldwide LAN. We needed his expertise to solve the routing and network integration issues. Another member of the team was one of our best and most progressive system administrators. He knew the UNIX mail environment inside and out as well as UNIX administration, so he could help tackle the mail issues," noted Miller. "Another person was a very good generalist with PCs in the existing environment. He knew NetWare, he knew the UNIX host, he knew the Telnet connections and what people did on the UNIX host. So he had the user perspective of our existing environment. And then the fourth individual was the lead in the architecture group in our IS department. He served as the project manager for this effort and was the communicator to the rest of the organization."
According to Miller, a key part of the rapid development of the Windows subnetwork model in a UNIX-dominated culture was not only the quality of the people on the team, but the way they began their work together. "We selected the four people from IS and relocated them to a temporary location in our operation," explains Miller. "We transplanted them from their existing environment, one in which they were familiar, and put them into this new environment with developers for Windows NT around them, so they got indoctrinated into the PC and Windows way of thinking. They lived by this prototype configuration and its constraints. They became part of the team here." Miller points out that this process served a valuable technology transfer role as the "borrowed" IS staff returned to their regular tasks weeks later when the Windows-based solution was rolled out through corporate headquarters.
"These four individuals went back and got more actively involved in the next stage of technology transfer as each one of them conversed with others in their own functional area," says Miller. "It was better for them to reside back in the IS environment and take this new-found knowledge and share it with the people around them."
"Our desire was to solve our routing problem with one protocol. Microsoft's TCP/IP for Windows for Workgroups was the only TCP/IP protocol that we could use and unplug the native NetBEUI protocol ..."
Matt Miller, Technical Lead,
Sequent Computer Systems
The Development Process
Miller and an associate put together the initial rough prototype of the Windows subnetwork in about six weeks, using an early beta release of the Windows NT operating system. This prototype involved approximately 20 users and included a Sequent two-processor WinServer machine running Windows NT Advanced Server, Windows for Workgroups client PCs, the Microsoft Mail SMTP Gateway, and fax and remote access servers. The Windows-based network used the NetBEUI protocol (Microsoft's nonroutable networking protocol) along with a simple terminal connection to the UNIX hosts. Sequent upper management was convinced by this basic proof of concept to give the go-ahead to dedicate the four additional staff to the full integration effort.
Acording to Miller, before the team could declare success and offer a Windows-based network with reliable UNIX integration to the company's workgroups, they had to solve challenges in three key areas: electronic mail, file and print sharing, and remote access. Underlying all of these issues, however, was the challenge of ensuring reliable routing of communications between the numerous subnetworks and the UNIX systems over the wide area network.
For the various subnetworks to communicate with each other and the UNIX services, Miller's team used the built-in TCP/IP protocol support in both Windows NT and Windows for Workgroups. "Our desire was to solve our routing problem with one protocol," explains Miller. "Microsoft's TCP/IP for Windows for Workgroups was the only TCP/IP protocol that we could use and unplug the native NetBEUI protocol. We tried a number of other protocols from other vendors. But it was the only other one that implemented the right kind of TCP/IP standards to allow us to get full Windows for Workgroups functionality with just TCP/IP. The user doesn't know any different, but they are able to browse all the workgroups throughout the campus and all the individuals and their individual drives and whatever people may share. So, even though somebody's three buildings over and I'm hopping across three routers and three different subnetworks, I can still browse their resources, do network DDE (dynamic data exchange), and everything else via the routable TCP/IP." While this routable protocol enabled basic wide-area-network communication and got both Windows and UNIX systems talking in a common language, Miller explains that there remained a "broadcasting" challenge. The network operating system in Windows NT uses a broadcast model that the UNIX systems do not. As Miller explains, for each Windows for Workgroups workstation, the default is to send out a broadcast signal across the entire network to update itself on what servers are active, confirm logins, search for available resources, and other tasks. This could lead to a high level of network "noise" that decreased performance.
"That was easy, putting the gateway in place. Our challenge was managing our mail aliases."
Matt Miller, Technical Lead,
Sequent Computer Systems
Miller points out that if Sequent was using a Windows NT-based client workstation for each user, this would not be a problem because Windows NT maintains a local "host file" or database that tracks the resources across the wide area network and minimizes the need for broadcasting. However, Sequent wished to use Windows for Workgroups on each client machine. The Windows for Workgroups host file, due to MS-DOS® memory limits, currently has a limit of roughly 60 entries, not enough to store adequate information on Sequent's vast network. Consequently, broadcast traffic could be considerable as the number of users grew.
To keep the network from quickly becoming crowded with a high level of noise from all of the broadcasts, Miller's team used a combination of techniques. They "tuned" the routers on their three network backbones in the corporate campus to only broadcast certain types of packets and to filter out, for example, a broadcast looking for active servers. And they carefully set up the server domains so that Windows NT servers around the world would limit general broadcasting primarily to their local subnetworks.
A central North American domain server at Sequent corporate headquarters in Beaverton, Oregon, maintains the master user account database for all domestic workers. Servers at each Sequent site around the country are part of that domain and maintain a replica of the master file by automatically receiving updates every 15 minutes. In this way, a user in New York gains network login privileges through her local subnetwork server via Windows for Workgroups. The individual login request is not broadcast across the entire wide area network. A similar domain model, each with a master server, has been established for Sequent's Europe and Asia Pacific regions.
E-Mail Integration Poses Alias Challenge
With the routing issue solved, Miller's team turned to electronic mail integration. "We have a worldwide mail backbone technology already in place-UNIX Mail-and we saw no reason to replace that," notes Miller. "So our challenge was: how do we use the Microsoft Mail client, which is a much nicer, more capable client, on the PC desktop but use the backbone where appropriate?" The answer, according to Miller, was fairly straightforward. They chose the Microsoft Mail SMTP Gateway for UNIX. "That was easy, putting the gateway in place. Our challenge was managing our mail aliases."
"We came up with a scheme where there is basically a virtual gateway name ... The UNIX host just gives the next message to the next available MS-DOS gateway machine."
Matt Miller, Technical Lead,
Sequent Computer Systems
Sequent's UNIX-based e-mail system had more than 5,000 existing mail aliases (shorthand names for groups of mail users) that were used every day as well as an established corporate procedure for creating and administering new aliases. Rather than try to maintain a separate alias system for Windows-based mail, Sequent chose to keep using the UNIX system's alias and address structure. A team member wrote a small custom program that takes the alias file on the UNIX host each night and reformats it and copies it into the Microsoft Mail address list.
According to Miller, the ability of the Microsoft Mail system to embed a document such as a worksheet in a mail message is a strong advantage over the UNIX system. Since only users of Windows can send embedded documents to each other, there needed to be a way of looking at the address list and telling who was on Microsoft Mail. Miller's team came up with a way to identify a Microsoft Mail user by displaying both full name and login name together on the same line. The names of UNIX-only users are displayed as either their full name or their login name, but not both. A user can glance at the address list to see whether a person can receive a message with an embedded document.
With the multiple-system addressing problem solved, and as more and more users moved to Microsoft Mail, the development team for Windows faced a second addressing issue concerning the growing number of gateways between the UNIX hosts and the Microsoft Mail system in use at the corporate headquarters site.
Typically in an Internet / MS-DOS gateway environment, the user's mail address must include the name of the gateway being used. "If we add another mail gateway," explains Miller, "then we've got to change the addresses of the people who are serviced by that second mail gateway. And we-and the users-did not want to be changing addresses regularly."
This wouldn't be a problem at a regional Sequent office where the number of users would never exceed the capacity of the gateway on a single Windows subnetwork. But for the 1,000-plus workers at corporate headquarters, it was inevitable that more gateways would be required as more users adopted Microsoft Mail. "So what we put together is best described as some tricks between the MS-DOS-based mail gateways and the UNIX host that feeds them," notes Miller. "We can take the UNIX host and have it look at a bank of MS-DOS machines as one logical gateway. So that we'll be able to add multiple MS-DOS mail gateway machines thereby adding capacity and not change any of the architecture or implementation at all. And that was crucial."
"... the RLN product was the only one we knew about at the time with which you could access Windows NT servers, a NetWare server, or TCP/IP connected servers simultaneously from a remote PC."
Matt Miller, Technical Lead,
Sequent Computer Systems
A set of custom code running on the UNIX host works out a queuing process between the UNIX host and the gateway machines. "We came up with a scheme where there is basically a virtual gateway name and so you send mail at, for example, "Mmiller@USHQGW.Sequent.Com." And in reality the gateway machines are USHQGW1, GW2, GW3, however many you add on," Miller explains. "The UNIX host just gives the next message to the next available MS-DOS gateway machine." Not surprisingly, this solution drew on Sequent's experience with multiprocessor systems. Says Miller, "It mimics what you would do with multiple processes running on a symmetrical multiple processor machine, except this time with multiple MS-DOS gateway machines."
Preserving the Printer Infrastructure
Another key challenge for Miller's team was to find a way to preserve Sequent's existing worldwide network of laser printers. These printers are connected to UNIX hosts either through ethernet or a direct serial link. Those printers that were "hard-wired" to a host via a serial connection posed the greatest challenge, since the primary option for Windows integration was to set up a separate Windows-based print server on a network connection to that specific printer. "The requirement for this project was that users should be able to connect to a printer via their normal application for Windows," says Miller.
To achieve that goal without expensive hardware additions, the development team sought a way to minimize the disruption to the existing architecture and just layer "Windows" capabilities over the existing UNIX environment. The answer came in a third-party product called LM Server from Syntax Corporation. As Miller explains, this is an application that runs simultaneously with other applications on a UNIX host and makes that host appear as a server to Windows-based client PCs. As a result, a Windows for Workgroups user can print a file to any printer on the UNIX network. Although the print command actually goes through the UNIX host, to users of Windows it works as if they printed to a local printer connected to their PC.
Remote Access to UNIX and Windows
The third key area of integration to be tackled was that of providing users with "full-service" remote access to both UNIX and Windows-based systems. The objective was to provide the end users with a common set of services independent of whether the user was in the office directly connected to the network, at home using a desktop PC, or on the road using a portable PC. Miller's team turned to another third-party product, Remote LAN Node, or RLN, from Digital Communication Associates (DCA).
As Miller points out, the justification for remote access services was fairly straightforward: "Our president wanted a portable computer running Microsoft Mail so he could read his mail on the plane." This was part of a much larger goal to give Sequent's several-hundred-member worldwide sales force, as well as all members of the engineering development group, the freedom to use both the new Windows-based services and existing UNIX systems on the road and from home PCs. The fact that Sequent has several legacy systems running a UNIX version of Novell NetWare added another dimension in terms of remote access services. "We had this requirement to also gain access to the NetWare file and print services and the RLN product was the only one we knew about at the time with which you could access Windows NT servers, a NetWare server, or TCP/IP connected servers simultaneously from a remote PC."
In Sequent's network design, each Windows subnetwork has a dedicated PC server running RLN with 14.4K modem lines to support remote access users.
Implementation Costs
Miller estimates that the cost to build the Windows infrastructure at the corporate headquarters and to develop the subnetwork model that can be copied by the regional offices totaled about $200,000. This figure includes both hardware and software for the several-hundred corporate campus users and the gateways, WinServer machines, routers, and upgrades to the wide area network. These infrastructure expenses at the headquarters, Miller notes, are enough to support a worldwide integrated network based on UNIX and Windows for some 5,000 users.
Development Time
The six-person development team moved quickly to address the Windows integration issues noted above. The proof-of-concept model was completed in mid-February of 1993, following six weeks of work by Miller and his associate. Two alpha prototypes followed in March and April, each one working out more of the integration issues while bringing online about 40 users on Sequent's Beaverton, Oregon, corporate campus. In mid-May, the Windows-based network was expanded to 120 beta users spread across five buildings. The final configuration was rolled out in mid-June, when the development team turned over the Windows platform components to Sequent's IS operations for ongoing maintenance and support. Throughout the summer of 1993, other groups on the corporate campus were brought online as they requested the Windows services. The same Windows sub-network model was made available to Sequent's 40-plus offices around the world.
Miller points out that the six-month development time for creating the UNIX-integrated package of Windows services was quite rapid, given that the team was working with Windows NT beta releases during the entire process, and that four of the six team members had little or no experience with Windows.
Ongoing Support and Training
At its corporate campus, Sequent offers regular on-site classes using a local contractor to train the company's growing ranks of new users in the Windows operating system and applications for Windows. In addition, each department or workgroup that requests to be set up with the new package of Windows services is required to assign one person as the workgroup coordinator. The development team trains this coordinator on how to install each user's workstation. The installation is actually quite straightforward. The workgroup coordinator boots up each machine with a floppy disk that guides them though a series of setup questions (such as user account information) and then automatically connects the server and installs and configures the necessary software on the workstation.
Sequent's IS group estimates that as the majority of the company's 1,600 employees begin using the Windows and UNIX services, a total of 14-16 internal staff will be needed to provide users worldwide with support for the Windows-based subnetworks and applications.
For More Information
For more information about Microsoft products, call the Microsoft Sales Information Center at (800) 426-9400. In Canada, call the Microsoft Canada Customer Support Centre at (800) 563-9048. If you require text telephone services (TT/TDD), call (800) 892-5234 in the United States or (905) 568-9641 in Canada. Outside the 50 United States and Canada, please contact your local Microsoft subsidiary.
This case study is for informational purposes only. MICROSOFT
MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS SUMMARY.
© 1993 Microsoft Corporation. All rights reserved. Printed
in the USA.
Microsoft, MS DOS, and MS are registered trademarks and Windows
and Windows NT are trademarks of Microsoft Corporation.
Intel is a registered trademark of Intel Corporation. Macintosh
is a registered trademark of Apple Computer, Inc. NetWare and
Novell are registered trademarks of Novell, Inc. Sequent
and Symmetry are registered trademarks of Sequent Computer Systems,
Inc. UNIX is a registered trademark of UNIX Systems Laboratories,
a wholly owned subsidiary of Novell, Inc.
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