Welcome to Certifiable, your exam prep headquarters. Here you'll find questions about some of the tricky areas that are fair game for the certification exams. Following the questions, you'll find the correct answers and explanatory text. We change the questions weekly.

Questions (February 2, 2001)
Answers (February 2, 2001)

Because I haven't taught the Microsoft course that corresponds to Exam 70-068: Implementing and Supporting Microsoft Windows NT Server 4.0 in the Enterprise in a long time, I looked back at my instructor's manual to find which topics were the hardest for my students to understand. The exercise reminded me that the questions about scaling a domain infrastructure to handle the needs of a large company are much the same now as they were then. Everything boils down to ensuring that users can log on and access resources on the network, sizing the servers to handle the expected load and then monitoring them afterward, preparing for disasters, and configuring connectivity between networks with less-than-ideal communications links.

This week's questions cover some of the planning issues you'll find on the exam. For these questions, it's much more important for you to know WHY the answer is correct than to know the correct answer. If you know why one choice is better than another, you should be able to answer a question about a different, but related topic. In addition, if you look around at your peers, you'll find that the ones who know why one choice is better are the ones who get paid more than the people who just memorized enough to pass the exam.

Only 26 days remain for you to finish the NT 4.0 MCSE, so good luck and study hard!

Questions (February 2, 2001)

Question 1
You are the network administrator for a large company with offices in Chicago, Los Angeles, and New York. The company headquarters in Chicago employs 33,000 people and has 25,000 desktop computers and 3000 laptops. The Los Angeles and New York offices each have 5000 people, 3000 desktop computers, and 1500 laptops. The Los Angeles and New York offices connect to the Chicago office via a dedicated T1 connection.

You want to administer user accounts for the company from the Chicago office, but you want administrators at each local office to manage the local computers, printers, and other resources. All users in the company must be able to access shared files on any computer in the company. Which of the following domain models meets these goals?

  1. Single domain model
  2. Single Master domain model
  3. Multiple Master domain model
  4. Complete Trust model

Question 2
You are the network administrator for a large company with offices in Chicago, Los Angeles, and New York. The company headquarters in Chicago employs 3000 people and has 2000 desktop computers and 1000 laptops. The Los Angeles and New York offices each have 5000 people, 3000 desktop computers, and 1500 laptops. The Los Angeles and New York offices connect to the Chicago office via a dedicated 256Kbps fractional T1 connection.

You administer user accounts for the company from the Chicago office, but administrators at each local office manage the local computers, printers, and other resources. All users in the company have access to shared files on any computer in the company.

Your users complain that logging on, accessing a shared directory for the first time, and browsing for computers at other sites are slow operations. Assuming you implemented the Single Master domain model, which of the following changes to your network infrastructure will improve the performance of those operations?

  1. Placing a BDC for the master domain at each site.
  2. Placing a BDC for each resource domain in Chicago.
  3. Placing a BDC for each remote resource domain at each site.
  4. Placing a WINS server in Los Angeles and New York and configuring them as push-pull partners with a WINS server in Chicago.
  5. Placing a caching-only DNS server in Los Angeles and New York.
  6. Moving the resource domain controllers to faster computers.

Question 3
You are the network administrator for a large company with offices in Chicago, Los Angeles, and New York. The company headquarters in Chicago employs 3000 people and has 2000 desktop computers and 1000 laptops. The Los Angeles and New York offices each have 5000 people, 3000 desktop computers, and 1500 laptops. The Los Angeles and New York offices connect to the Chicago office via a dedicated 256Kbps fractional T1 connection.

When you use Performance Monitor to monitor the PDC located in Chicago, you notice that the Processor: % Processor Time counter is consistently above 80 percent, the Physical Disk: Avg. Disk Queue Length counter is averaging 2.6, and the Memory: Pages/sec counter is averaging 3.2. Which of the following enhancements should yield the most improvement in this server's performance?

  1. Replace the CPU with a faster CPU.
  2. Replace the motherboard with a dual CPU motherboard.
  3. Replace the hard disk controller with a higher performance controller.
  4. Increase the RAM in the system.

Answers (February 2, 2001)

Answer to Question 1
The correct answer is C—Multiple Master domain model. The key fact in this question is that a single location will manage user accounts while administrators at each site will manage the local resources. The Single Master or Multiple Master domain models are the appropriate choices to meet that requirement. Because Windows NT 4.0 domains have a limit of 40,000 accounts each, 43,000 total users forces you to choose the Multiple Master domain model. Without any other constraints, the logical choice is to split the accounts evenly between two master domains. Given the physical locations for the offices, creating a resource domain for each office makes the most sense. Users can access all shared resources on the network if the Chicago, Los Angeles, and New York resource domains trust both master domains.

Answer to Question 2
The correct answer is A—Placing a BDC for the master domain at each site. With a Single Master domain model, user accounts are in the master domain and computer accounts are in the resource domains. Each time a user needs to authenticate, the computers must pass the request to their resource domain's PDC, which passes the request to a domain controller of the master domain. This process is known as Pass-Through Authentication. PDCs manage the trust relationships between domains, but BDCs can authenticate user credentials as well. Placing a BDC for the master domain at each remote site lets the authentication traffic stay on the faster LAN rather than travelling across the slower WAN link to Chicago. Browsing will also be faster because each resource domain will inform the master domain master browser about changes, and each BDC for the master domain will maintain a copy of the browse list for the master domain and the resource domains.

Answer the Question 3
The correct answer is D—Increase the RAM in the system. In Windows NT, all applications share physical memory using a memory management scheme, known as "virtual memory," in which the OS maps pages of virtual memory to pages of physical memory. When an application requests more physical memory than the OS has available, NT copies pages allocated to another application to the hard disk and allocates the memory to the requesting application. This is known as "page swapping."

Windows NT is a preemptive multitasking OS, which means that the OS shares the CPU by letting each application run for only a fixed amount of time. When the system doesn't have enough physical memory to support all the running applications, NT must swap pages of memory from the disk into the pages of physical memory before an application can access the memory. An application that has access to the CPU has precedence over applications that don't; therefore, the cycle of activating and deactivating applications causes the system to copy pages of memory back and forth from RAM to the hard disk.

Hard disk operations require the most time of any operation NT performs; therefore, improving hard disk performance will yield the greatest performance improvement. For this question, however, the best way to improve hard disk performance isn't to use the hard disk at all. You can accomplish that goal by increasing the amount of RAM to the point that NT has enough physical memory to support all the active applications. If a system already has as much RAM as it can support, replacing the hard disk controller and the hard disks with higher performance components will improve performance.