\[Editor's Note: This article assumes you understand Windows NT domains and trust relationships. For information on these and related topics, see Volume 2, Chapter 4 of the Microsoft Windows NT Resource Kit for Windows NT 3.51 and the related Windows NT Magazine articles listed in this article.\]
Sam Blunk, Texas Instruments's manager of
information systems and services NT server engineering.
Texas Instruments (TI) is in the business of keeping up on the latest technology and finding ways to leverage that technology in its products. The company produces various products, including consumer electronics, computing devices, semiconductors, avionics, weapons guidance systems, software tools and services, precision-engineered materials, and sensors and control products. TI employs about 59,000 people worldwide, and they work on about 50,000 workstations.
When TI needed to connect its various users worldwide, the company implemented Windows NT Advanced Server 3.1, a new technology at the time, to replace its installed base of OS/2 1.3 LAN Manager servers. In the fourth quarter of 1993, five months after Microsoft released NT 3.1, TI began to deploy this new technology to 17 countries and almost 40,000 users worldwide. Figure 1 shows TI's global enterprise network.
TI uses Windows for Workgroups 3.11 for its DOS-based clients and is extending NT Workstation to its desktop clients and Windows 95 to notebooks until NT incorporates Plug and Play (PnP). NT transformed TI's client/server environment: The company moved from a fragmented environment with many small standalone domains to an NT network in which two-thirds of the company is linked by domain trusts.
From LAN Manager to NT
TI's production environment requires 24 X 7 availability, so the company emphasizes the importance of rapid restarts and gathering good (preferably dynamic) debug information at the time of a system failure. Unfortunately, the Intel-based server environment of the early 1990s wasn't up to this task and suffered in comparison to TI's mature and reliable mainframe systems. At the time, TI's 486/33- and 486/66-based servers ran Microsoft LAN Manager on OS/2 1.3. The rapidly growing popularity of the server environment quickly stretched beyond LAN Manager's capabilities.
The combination of OS/2 1.3 and LAN Manager suffered from several limitations, including
- Limited architecture: Memory addressing and storage capacity were limited and forced TI to use many small servers.
- Limited error recovery and debugging facilities: Troubleshooting system failures required a realtime dialup from Microsoft.
- Duplicate accounts: Users needed a separate user ID and password for each server they accessed outside their logon network. If these user IDs and passwords slipped out of synchronization, the users received an Error 5: Access denied message. TI's biggest Help desk problem was administering and troubleshooting duplicate accounts and passwords.
- Limited support: After the introduction of NT, TI was frustrated by Microsoft's lack of support for LAN Manager. "Complaining to Microsoft was like pushing your finger into the Pillsbury Doughboy," one TI manager said. "It makes a dent at the time, but as soon as you turn away, it pops back out as though nothing had happened."
Despite TI's frustration with Microsoft, NT was the top contender as a successor to TI's LAN Manager systems. Table 1 lists some of the problems TI faced with LAN Manager and TI's NT engineering team's solutions. TI chose NT because administrators and users were familiar with the Microsoft networking environment, and much of this environment remained unchanged from LAN Manager to NT. The Microsoft applications, such as SQL Server, that TI used under LAN Manager were available on NT, and NT's 32-bit addressing and symmetric multiprocessing (SMP) support finally created an opportunity for power and expandability. NT was Microsoft's flagship operating system and had the company's full support. NT had greatly improved system recovery over LAN Manager, and eventually incorporated automatic failure notification, dump, and system restart. NT's domain-trust model, which Microsoft expanded over LAN Manager's, largely eliminated the need for duplicate accounts between domains. Prices for new NT software and upgrades to existing licenses also were very favorable--not an insignificant issue in a company such as TI, which had hundreds of LAN Manager licenses.
The TI NT engineering team's project to deploy NT followed a phased approach, as you see in Figure 2. TI planned its domestic strategy from January to May 1994; domestic deployment began in June 1994 and ended in December that year. Between January and September 1995, TI planned its international strategy for three major regions: Japan, the Asia Pacific rim countries (Singapore, Malaysia, Philippines, Hong Kong, Taiwan, and Australia), and Europe (France, Germany, Italy, and the UK, initially). TI put its international plan into action between July and December 1995. The domestic integration of other master domains to the trusted network has been ongoing since January 1996.
To engineer NT Server 3.1 into TI's production environment, the TI team had to plan the implementation in three areas: server, support, and architecture.
- Server: TI needed to design a generic NT server. Choosing a platform was the first and most important task because all other decisions would be based on the chosen platform. The NT engineering team chose Compaq's ProLiant and ProSignia servers as the standard production NT platform for a large part of the NT trusted network. TI chose those servers instead of faster RISC-based processors because the company's primary concerns were reliability, manageability, and expandability (not just speed). TI also chose the Intel-based servers because of the wide variety of server applications available for the x86 architecture. The team knew that Compaq's hardware is highly regarded in the trade press and is a value leader in its class for management features and expandability.
- Support: The TI project had to include NT Server in the existing TI IS support structure. The NT engineering team had to write full documentation to cover everything from supporting a domain architecture to properly rebooting an NT server. The team selected and recommended NT Server training for all staff involved. This training to show that NT Server had evolved beyond LAN Manager was critical for the project's success. Although preaching NT's benefits to the masses wasn't in TI's plan, some evangelism was necessary.
- Architecture: The team's challenge was to design a domain architecture for the entire company and strike a balance between the engineers' desire for independent domains and the need for a cohesive, supportable enterprise network. As part of the company culture, TI's engineers are known for creating their own domains with departmental machines. Unlike users of mainframe technology, TI users with a few hundred dollars in their project account can turn a desktop machine on its side, call it a server, and create a personal NT domain. This ability to create independent domains is not bad; workgroups and departments can have cheap computing power not possible a few years ago. However, the combination of easily created NT domains and TI's innovative company culture complicates the systems architect's job.
TI's NT trusted domain network of almost 40,000 accounts comprises only 10 of the hundreds of domains throughout the company--the rest are standalone domains. Microsoft's domain-trust models work best when a company has at most a few IS organizations. Ironically, because NT Server is a decentralized computing environment, the amount of trouble a company will have designing and deploying NT Server on a large scale is proportional to how decentralized the administration is. Most major sites at TI have their own Help desk and IS administrative staff, so fitting Microsoft's NT domain-trust model into TI's IS infrastructure was a significant challenge.
Because stress testing an NT server with realistic loads was so difficult in 1994, TI initially employed NT on a few servers for internal IS department use only. The company migrated LAN Manager users to NT in groups to build the infrastructure step by step and record performance data.
This approach helped TI gain experience in moving user accounts and data from older systems. When the company was satisfied with the results, it began conversions in earnest.
TI converted about three LAN Manager servers into each NT Server and carefully scripted the process for future conversions. The script covered every contingency, from ensuring a dedicated multiport was available to speed data transfers to guaranteeing the right type of power (with the right plugs) was available in the computer room. Eventually, TI's NT engineering team could hand off the domestic conversions to another group because the process was so carefully laid out.
TI initially created two US master domains. Then the company brought a third domain online to limit each existing domain to 10,000 accounts and to help distribute administration.
|NT was the top contender as a successor to TI's LAN Manager systems.|
To plan for the international NT deployment, TI used different NT architectural models within different regions. Ultimately, the company chose three domain models--multiple master domain, master domain, and single domain. TI's NT domain design across the entire enterprise uses a multiple master domain model with master domains in the US, Japan, Europe, and the Asia Pacific regions. Settling on the multiple-master domain model was easy because it is the only design that can support a potential user base of 40,000 to 45,000 accounts.
TI organized its domains primarily along administrative boundaries, although geography and network topology influenced the decisions. TI Japan is a good example of the single-domain model. Because all of TI Japan uses the same administrative group, a single-domain model was the best choice.
In the Asia Pacific (APR1) and European (EUROPE1) regions, each country had its own administrative organization and security requirements. In planning meetings for these regions, the deployment team agreed to build a resource domain for each country and a master account domain for each region. This organization gave each country's administrators full control over their resource domain and gave two administrators from each country full administrative rights in their master domain.
Shortly after each planning trip, the deployment team returned to its home region to install NT at a major site. The local administrators attended to observe the conversion. They then returned to their sites to convert their servers. TI scheduled the conversions to occur on weekends with no more than one conversion per region on a given weekend so that the engineers could moderate the load on the region's Primary Domain Controller (PDC).
Because of impending network upgrades, TI was unable to employ the Windows Internet Name Service (WINS) concurrently with the international domains--the company installed WINS servers several months after the conversion. TI used lmhosts files instead of WINS to map NetBIOS computer names to IP addresses. This workaround caused many communication and coordination problems. For example, if a regional administrator created a new Backup Domain Controller (BDC) in a master domain and didn't notify the other administrators around the world so they could update all server lmhosts files, or if the BDC was promoted to PDC to make mass account creation easier, the PDC for the master domain seemed to disappear from the network. Notifying regional systems administrators to add the new PDC's IP address to the lmhosts file on their server corrected the problem.
In a truly useful trusted network, NT domains outside the network can connect to it to take advantage of the network's Remote Access Service (RAS) and Systems Management Server (SMS) resources and eliminate the need for duplicate accounts between their domain and the trusted network. In January 1996, TI began a series of integrations to set up two-way trusts with master domains from organizations such as the Systems Group and Materials & Controls Group.
These integrations have complicated the administration of the company's trusted network in several ways. Two of the most significant impacts are in the area of trusts and customer support. Adding master domains and domain controllers to a multiple-master domain NT network significantly increased the number of domain trusts and trust sessions that TI had to monitor and repair. Every new master domain has a support organization, which complicates user support. The users need to know which group to call, and if they call the wrong place, the support organization needs to be able to quickly route the call to the correct group or have rights to fix the problem themselves. TI soon realized that support issues across domains were as important as the technical issues of domain integration. To see how one member of TI's NT engineering team felt about the project, see the sidebar, "An Interview with TI."
Challenge to Manage NT
The biggest tasks now involve NT management issues. The cost of support far outweighs the cost of soft-|ware, and few tools exist for the enterprise in areas such as audit data collection and analysis and storage management. TI is watching the road to NT 5.0 carefully, and positioning the enterprise to take advantage of its much-needed enhancements as they become available.
RELATED ARTICLES IN WINDOWS NT MAGAZINE
|Mark Minasi,||"Domains and Workgroups," April 1996|
|Ed Tittel and Mary Madden,||"Domains, Trust Relationships, and Groups," June 1996|